Sealing device

Abstract

To provide a sealing device capable of being installed in a small space, and having improved sealing performance by a seal lip.SOLUTION: A sealing member 11 is composed of a core material 12 and an elastic member 13, and comprises a plurality of seal lips 13b, 13c composed of the elastic member 13. A slinger 15 comprises a slinger inner diameter side cylindrical part 15a arranged on a base space 5a side, a slinger ring part 15b, and a slinger outer diameter side cylindrical part 15c, and a deep-inside end part 15ca in a sealed space 4 of the slinger outer diameter side cylindrical part 15c is arranged in an additional space 5b. A sealing device 10 is arranged so that the plurality of seal lips 13b, 13c are in contact with an outer peripheral surface 15cb of the slinger outer diameter side cylindrical part 15c.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a sealing device having a seal member and a slinger. [Background technology]

[0002] Conventionally, many sealing devices have been proposed for sealing the sealed space of a bearing device, which have a seal lip formed from an elastic material, and when the shaft rotates, the seal lip slides against a slinger to seal the sealed space (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 7-65621 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, various types of electrically assisted bicycles have been implemented that use a drive unit that integrates the motor and control unit for providing the electric assistance. These bicycle drive units have been made lighter and smaller to improve handling and allow for greater freedom in vehicle body design. For example, the drive unit is disposed in a small space near the pedals.

[0005] Therefore, in this type of drive unit, the bearing device installed inside must naturally be small, and the sealing device that seals the sealed space of the bearing device is also small in size corresponding to the size of the bearing device.

[0006] For example, in a case where the space between the housing that covers the bearing device and the rotating shaft on the axial outside of the bearing device is used as the installation space for the sealing device, the axial dimension of the installation space (thickness direction of the sealing device) is smaller than the radial dimension, and typically the axial dimension of the installation space is about a few mm.

[0007] As described above, the installation space of a sealing device used in a narrow space is limited to a small dimension and shape, and in particular, the axial dimension of the installation space is extremely small, so that hardly any sealing devices having a seal lip for improving sealing performance have been proposed in the past.

[0008] The present invention has been proposed in consideration of the above circumstances, and an object of the present invention is to provide a sealing device which can be installed in a small space and has a seal lip which improves the sealing performance. [Means for solving the problem]

[0009] In order to achieve the above object, the sealing device of the present invention is a sealing device comprising a seal member and a slinger for sealing a space to be sealed between an outer diameter member and an inner diameter member which rotate relative to one another, the space to be sealed including a base space which is a main installation space of the sealing device, and an additional space which communicates with the inner part of the space to be sealed along the axial direction from the base space and narrows in a stepped manner from both ends of the radial direction of the base space, the seal member being made of a core material and an elastic member which is integral with the core material, and comprising a plurality of seal lips made of the elastic member, and a sealing member which is formed between the inner diameter member and the outer diameter member, The slinger is configured to fit into the outer circumferential surface of the inner diameter member on the base space side, and the slinger comprises a slinger inner diameter side cylindrical portion that fits into the outer circumferential surface of the inner diameter member on the base space side, a slinger ring portion extending outward from the end of the slinger inner diameter side cylindrical portion, and a slinger outer diameter side cylindrical portion extending axially from the outer diameter side end of the slinger ring portion toward the rear of the sealed space, and the rear end of the slinger outer diameter side cylindrical portion within the sealed space is arranged in the additional space, and the multiple seal lips are arranged so as to contact the outer circumferential surface of the slinger outer diameter side cylindrical portion. Effect of the Invention

[0010] Since the present invention has the above-mentioned configuration, it can be installed in a small space, and the sealing performance can be improved by the seal lip. [Brief description of the drawings]

[0011] [Figure 1] 2 is a vertical sectional view of a bearing device, which diagrammatically illustrates an installation space of the sealing device according to the embodiment of the present invention. FIG. [Diagram 2] 1 is a longitudinal sectional view of a main part showing an installed state of a sealing device according to a first embodiment. FIG. [Diagram 3] FIG. 11 is a longitudinal sectional view of a main part showing an installed state of a sealing device according to a second embodiment. [Figure 4] FIG. 11 is a longitudinal sectional view of a main part showing an installed state of a sealing device according to a third embodiment. [Diagram 5] FIG. 11 is a longitudinal sectional view of a main part showing an installed state of a sealing device according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Various embodiments of the present invention will now be described with reference to the accompanying drawings. First, the basic configurations of the sealing devices 10, 10A, 10B, and 10C according to these embodiments will be described.

[0013] The sealing devices 10, 10A, 10B, and 10C according to these embodiments include a seal member 11 and a slinger 15 that seal the sealed space 4 between an outer diameter member 1 and an inner diameter member 2 that rotate relative to one another (see Figs. 1 to 5).

[0014] The sealed space 4 includes a base space 5a which is the main arrangement space of the sealing device 10, and an additional space 5b which communicates with the base space 5a along the axial direction B and is tapered in a stepped manner from both ends of the base space 5a in the radial direction A (see Figures 1 to 5 for the above).

[0015] The seal member 11 is made of a core material 12 and an elastic member 13 that is integral with the core material 12 (see Figs. 2 to 5). The seal member 11 also has a plurality of seal lips 13b, 13c that are made of the elastic member 13 (see Figs. 2 to 5). The seal member 11 is configured to fit into the inner circumferential surface 1a of the outer diameter member 1 (see Figs. 2 to 5).

[0016] The slinger 15 includes a slinger inner diameter side cylindrical portion 15a that fits into the outer peripheral surface 2a of the inner diameter member 2 on the base space 5a side, a slinger ring portion 15b that extends outward from ends 15aa, 15ab of the slinger inner diameter side cylindrical portion 15a, and a slinger outer diameter side cylindrical portion 15c that extends from an outer diameter side end portion 15ba of the slinger ring portion 15b along the axial direction B toward the back of the sealed space 4 (see Figs. 2 to 5). The slinger 15 is configured such that an end portion 15ca of the slinger outer diameter side cylindrical portion 15c that is located at the back of the sealed space is disposed in the additional space 5b (see Figs. 2 to 5).

[0017] The seal lips 13b, 13c of the seal member 11 are disposed so as to contact an outer circumferential surface 15cb of the slinger outer diameter side cylindrical portion 15c (see Figs. 2 to 5).

[0018] Next, the detailed configuration of the present sealing devices 10, 10A, 10B and a specific manner of mounting them to the sealed space 4 will be described with reference to FIGS.

[0019] FIG. 1 is a longitudinal sectional view of a bearing device 8, which is a schematic view of an installation space 5 of the sealing devices 10, 10A, 10B, and 10C. The installation space 5 is a part of the sealed space 4, as described below. FIG. 2 is a longitudinal sectional view of a main part showing an installation state of the sealing device 10 according to the first embodiment. FIG. 3 is a longitudinal sectional view of a main part showing an installation state of the sealing device 10A according to the second embodiment. FIG. 4 is a longitudinal sectional view of a main part showing an installation state of the sealing device 10B according to the third embodiment. FIG. 5 is a longitudinal sectional view of a main part showing an installation state of the sealing device 10C according to the fourth embodiment.

[0020] In the four embodiments shown in Figures 2 to 5, the shapes of the base space 5a and the additional space 5b are different from each other, but Figure 1 shows the mounting space 5 corresponding to the sealing device 10 shown in Figure 2 as a common schematic diagram for the four embodiments.

[0021] The bearing device 8 to which the sealing devices 10, 10A, 10B, and 10C are attached is a device disposed in a drive unit (not shown) of an electrically assisted bicycle. The drive unit is a unitized component that includes a motor and a control unit for providing electrically assisted power, and is a unit device disposed in a small space near the pedals of the bicycle, for example.

[0022] The bearing device 8 comprises an outer ring member 8a and an inner ring member 8b which rotate coaxially relative to each other around the axis of the rotating shaft 2b. In the example of Fig. 1, the outer ring member 8a is fitted to the housing 1 in the base space 5a, and the inner ring member 8b is fitted to the rotating shaft 2b in the base space 5a. An in-device space 6 between the outer ring member 8a and the inner ring member 8b is a space to be sealed, and a single row of rolling elements 8c is held in this in-device space 6 by a retainer (not shown). Sealing devices 10, 10A, 10B, and 10C are used to form this in-device space 6 in a sealed state.

[0023] The sealing devices 10, 10A, 10B, 10C are not directly mounted on the bearing device 8, but are mounted in the space between the housing 1 and the rotating shaft 2b outside the bearing device 8, as shown in Fig. 1. More specifically, this mounting space 5 is a space formed by the outer diameter member 1 made of the housing 1, and the inner diameter member 2 made of the rotating shaft 2b and the circlip 2c attached to the rotating shaft 2b, as shown in Fig. 1.

[0024] Before the sealing devices 10, 10A, 10B, and 10C are attached, the attachment space 5 is in communication with the in-apparatus space 6 of the bearing device 8, and the in-apparatus space 6 is sealed by attaching the sealing device 10 to this attachment space 5. That is, the sealed space 4 in this embodiment is configured to include the in-apparatus space 6 in the bearing device 8 and the attachment space 5 outside the bearing device 8.

[0025] In order to seal the internal space 6 of the bearing device 8, it is necessary to block not only one opening 8d of the bearing device 8 shown in FIG. 1, but also the other opening 8e. To do this, sealing devices of the same type as the sealing devices 10, 10A, 10B, and 10C described in this specification may be used, or other sealing devices may be used.

[0026] As shown in FIG. 1, the mounting space 5 is disposed on the outside Ba of the bearing device 8 in the axial direction B, i.e., outside the opening 8d, and includes an external base space 5a and an additional space 5b adjacent to the bearing device 8 and directly connected to the internal space 6 of the device.

[0027] Specifically, a step is formed on the surface of the housing 1 facing the rotating shaft 2b, a step recess 1b is formed on the outer side so that the step widens toward the outside Ba in the axial direction B, and a step protrusion 1c is formed via a step surface 1d at a position close to the bearing device 8. The space between the step recess 1b and the rotating shaft 2b in the radial direction A is the base space 5a, and the space between the step protrusion 1c and the circlip 2c in the radial direction A is the additional space 5b.

[0028] In other words, both the outer diameter member 1 and the inner diameter member 2 have a stepped (stepped) shape in which their opposing surfaces extend outward Ba in the axial direction B, and an installation space 5 is formed between the outer diameter member 1 and the inner diameter member 2, and is composed of a base space 5a and an additional space 5b, the shape of which is determined by the stepped shape.

[0029] Since the two spaces constituting the mounting space 5 are arranged in such positions, as shown in FIG. 1, the additional space 5b is located at a position that narrows in a stepped manner from both ends of the base space 5a in the radial direction A, and the mounting space 5 as a whole has a shape that narrows from the outside Ba to the inside Bb in the axial direction B.

[0030] In the four embodiments (examples shown in Figs. 2 to 5) described below, the base space 5a of these two spaces is a space for fitting the sealing devices 10, 10A, and 10B. That is, in the base space 5a, the seal member 11 fits (fits internally) into the outer diameter member 1, and the slinger 15 fits (fits externally) into the inner diameter member 2. In the embodiment shown in Fig. 5, the seal member 11 fits (fits internally) into the outer diameter member 1 in the additional space 5b, and the slinger 15 fits (fits externally) into the inner diameter member 2 in the base space 5a.

[0031] In these four examples, the core 12 is made of a metal material such as an iron-based material or a synthetic resin material, and the outer diameter member (housing) 1 is made of a non-ferrous metal such as a magnesium alloy or aluminum. To reduce the weight of an electric assisted bicycle, it is desirable to form the housing 1 from such a lightweight material other than iron. The slinger 15 and the inner diameter member 2 (rotating shaft 2b, circlip 2c) are both iron-based members.

[0032] First, a specific example of the arrangement of the sealing device 10 according to the first embodiment in the mounting space 5 will be described with reference to FIG.

[0033] The sealing device 10 has a seal member 11 made of a core material 12 made of an iron-based material and an elastic member 13 formed integrally with the core material 12, and further includes a slinger 15 made of metal.

[0034] The core material 12 comprises a core material outer diameter side cylindrical portion 12a which fits into the inner surface 1a of the outer diameter member 1 which corresponds to the surface of the step recess 1b, a core material disc portion 12b which extends from an end 12aa at the rear side (inner side Bb in the axial direction B) of the core material outer diameter side cylindrical portion 12a toward the inner diameter member 2 along the radial direction A, and a core material inner diameter side cylindrical portion 12c which extends from an end 12ba on the inner diameter side of the core material disc portion 12b toward the inner side Bb in the axial direction B along the surface of the step protrusion 1c.

[0035] The core 12 has an S-shaped crank shape in cross section, the core disk portion 12b is disposed along the step surface 1d, and the core outer diameter side cylindrical portion 12a and the core inner diameter side cylindrical portion 12c are substantially parallel to each other.

[0036] As shown in FIG. 2, when the sealing device 10 of this example is installed, the core outer diameter side cylindrical portion 12a and the core disc portion 12b are arranged in the base space 5a, and the core inner diameter side cylindrical portion 12c is arranged in the additional space 5b.

[0037] The elastic member 13 has an elastic base 13a arranged to cover the outer peripheral surface 12ab of the core material outer diameter side cylindrical portion 12a, the inner peripheral surface 12ac of the core material outer diameter side cylindrical portion 12a, the outer Ba surface 12bb in the axial direction B of the core material disc portion 12b, the inner peripheral surface 12ca of the core material inner diameter side cylindrical portion 12c, and the end face 12cb of the core material inner diameter side cylindrical portion 12c, and two seal lips 13b, 13c protruding from the end of the elastic base 13a on the inner diameter member 2 side.

[0038] The core outer diameter side cylindrical portion 12a is the main portion that is responsible for fitting with the outer diameter member 1. However, in this illustrated example, since the core material 12 and the outer diameter member 1 are made of different materials and have different linear expansion coefficients, and in consideration of the fact that the fitting force changes over time due to the different linear expansion coefficients, a cover portion 13d made of an elastic member 13 that covers the outer peripheral surface 12ab (the outer peripheral surface of the core material 12) of the core outer diameter side cylindrical portion 12a that is close to the inner peripheral surface 1a of the outer diameter member 1 is interposed for the fitting between the seal member 11 and the outer diameter member 1.

[0039] Furthermore, an annular protrusion 13da is provided on the outer circumferential surface of the cover portion 13d to improve the fitting force by elastic contact. In Fig. 2, the state of the protrusion 13da before elastic deformation is shown by a two-dot chain line.

[0040] As described above, the slinger 15 includes the slinger inner diameter side cylindrical portion 15a, the slinger ring portion 15b, and the slinger outer diameter side cylindrical portion 15c. The slinger inner diameter side cylindrical portion 15a is fitted to the outer circumferential surface 2a of the rotating shaft 2b serving as the inner diameter member 2.

[0041] More specifically, the slinger ring portion 15b is disposed so as to connect an end portion 15aa of the slinger inner diameter side cylindrical portion 15a on the outer side Ba in the axial direction B to an end portion 15cc of the slinger outer diameter side cylindrical portion 15c on the outer side Ba in the axial direction B. That is, the slinger 15 has an inverted U-shape in cross section as shown in the figure. The slinger outer diameter side cylindrical portion 15c is longer than the slinger inner diameter side cylindrical portion 15a, and extends to the outer peripheral surface side of the circlip 2c.

[0042] As shown in Figure 2, in this example, the slinger inner diameter side cylindrical portion 15a, the slinger circular ring portion 15b, and a portion of the slinger outer diameter side cylindrical portion 15c are arranged within the base space 5a, and a portion of the inner end 15ca (open end) side of the slinger outer diameter side cylindrical portion 15c within the sealed space is arranged within the additional space 5b.

[0043] 2, when the sealing device 10 is installed in the installation space 5, the seal member 11 and the slinger 15 are in a relationship in which the two seal lips 13b, 13c contact the outer peripheral surface 15cb of the slinger outer diameter side cylindrical portion 15c, and the two seal lips 13b, 13c come into sliding contact with the outer peripheral surface 15cb of the slinger outer diameter side cylindrical portion 15c due to the relative rotation of the outer diameter member 1 and the inner diameter member 2. The seal lips 13b, 13c shown by the two-dot chain line are in a state before elastic deformation.

[0044] In this embodiment, since the outer diameter member 1 and the inner diameter member 2 have the shapes shown in Fig. 2, the base space 5a has a generally rectangular cross-sectional shape as shown in the figure. The additional space 5b is a space that complements the base space 5a, and in the example shown in the figure, has a generally rectangular cross-sectional shape that is narrower than both end positions of the base space 5a.

[0045] In the mounting space 5 shown in the drawings, the thickness (depth) dimension (dimension in the axial direction B) of the base space 5a is sufficiently smaller than the dimension in the radial direction A, and the depth dimension of the additional space 5b is even smaller than the depth dimension of the base space 5a. Moreover, the dimension in the radial direction A of the additional space 5b is smaller than the dimension in the radial direction A of the base space 5a, and it exists only in a portion corresponding to the middle position in the radial direction A of the base space 5a.

[0046] In this way, the mounting space 5 is a distorted space that narrows toward the inside Bb in the axial direction B, which is formed by combining two annular flat and narrow spaces of different sizes, but by configuring the sealing device 10 as shown in the figure, the main parts of the two members can be arranged side by side in the radial direction A of the base space 5a, and the other parts can be arranged in the additional space 5b, which is a complementary space. In particular, the additional space 5b can be used as a part of the sliding contact space of the seal lips 13b, 13c.

[0047] In other words, according to this sealing device 10, even if the mounting space 5 is an uneven space surrounded by the outer diameter member 1, the inner diameter member 2, and the bearing device 8, the seal member 11 and the slinger 15 can be effectively arranged in the mounting space 5, and a sealing structure using a plurality of seal lips 13b, 13c can be achieved. As shown in the figure, the sealing performance can be improved by arranging one of the seal lips 13b, 13c in the additional space 5b.

[0048] Next, a specific example of the arrangement of the sealing device 10A according to the second embodiment in the mounting space 5 will be described with reference to FIG.

[0049] The sealing device 10A has a seal member 11 made of a core material 12 made of an iron-based material and an elastic member 13 formed integrally with the core material 12, and further includes a slinger 15 made of metal.

[0050] The core material 12 includes a core material outer diameter side cylindrical portion 12a that fits into the inner peripheral surface 1a of the outer diameter member 1 corresponding to the surface of the step recess 1b, a core material disk portion 12b that faces the inner diameter member 2 along the radial direction A from an end portion 12aa on the inside Bb in the axial direction B of the core material outer diameter side cylindrical portion 12a, and a core material inner diameter side cylindrical portion 12c that faces the inside Bb in the axial direction B along the surface of the step protrusion 1c from an end portion 12ba on the inside diameter side of the core material disk portion 12b. The core material 12 has an S-shaped crank shape in cross section, the core material disk portion 12b is disposed so as to follow the step surface 1d, and the core material outer diameter side cylindrical portion 12a and the core material inner diameter side cylindrical portion 12c are approximately parallel to each other.

[0051] As shown in FIG. 3, when the sealing device 10A of this example is installed, the core outer diameter side cylindrical portion 12a and the core disc portion 12b are arranged in the base space 5a, and the core inner diameter side cylindrical portion 12c is arranged in the additional space 5b.

[0052] The elastic member 13 has an elastic base 13a arranged to cover the outer peripheral surface 12ab of the core material outer diameter side cylindrical portion 12a, the inner peripheral surface 12ac of the core material outer diameter side cylindrical portion 12a, the outer Ba surface 12bb in the axial direction B of the core material disc portion 12b, the inner peripheral surface 12ca of the core material inner diameter side cylindrical portion 12c, and the end face 12cb (outer peripheral surface of the core material 12) of the core material inner diameter side cylindrical portion 12c, and two seal lips 13b, 13c protruding from the end of the elastic base 13a on the inner diameter member 2 side.

[0053] The core outer diameter side cylindrical portion 12a is the main portion that is responsible for fitting with the outer diameter member 1. However, in this illustrated example, the core material 12 and the outer diameter member 1 are made of different materials and have different linear expansion coefficients, so considering that the fitting force changes over time due to the different linear expansion coefficients, a cover portion 13d made of an elastic member 13 that covers the outer peripheral surface 12ab (the outer peripheral surface of the core material 12) of the core outer diameter side cylindrical portion 12a that is close to the inner peripheral surface 1a of the outer diameter member 1 is interposed for the fitting between the seal member 11 and the outer diameter member 1.

[0054] Furthermore, an annular protrusion 13da is provided on the outer circumferential surface of the cover portion 13d to improve the fitting force by elastic contact. In Fig. 3, the state of the protrusion 13da before elastic deformation is shown by a two-dot chain line.

[0055] As described above, the slinger 15 includes the slinger inner diameter side cylindrical portion 15a, the slinger ring portion 15b, and the slinger outer diameter side cylindrical portion 15c. The slinger inner diameter side cylindrical portion 15a is fitted to the outer circumferential surface 2a of the rotating shaft 2b serving as the inner diameter member 2.

[0056] More specifically, the slinger ring portion 15b is disposed so as to connect an end portion 15ab on the inside Bb in the axial direction B of the slinger inner diameter side cylindrical portion 15a to an end portion 15cc on the outside Ba in the axial direction B of the slinger outer diameter side cylindrical portion 15c. That is, the slinger 15 has an S-shaped crank shape in cross section as shown in the figure. The slinger outer diameter side cylindrical portion 15c extends to the outer peripheral surface side of the circlip 2c.

[0057] As shown in Figure 3, when the sealing device 10A of this example is installed, the slinger inner diameter side cylindrical portion 15a, the slinger circular ring portion 15b, and a portion of the slinger outer diameter side cylindrical portion 15c are arranged within the base space 5a, and a portion of the inner end 15ca (open end) side of the slinger outer diameter side cylindrical portion 15c within the sealed space is arranged within the additional space 5b.

[0058] 3, when the sealing device 10A is installed in the installation space 5, the seal member 11 and the slinger 15 are in a relationship in which the two seal lips 13b, 13c contact the outer peripheral surface 15cb of the slinger outer diameter side cylindrical portion 15c, and the two seal lips 13b, 13c come into sliding contact with the outer peripheral surface 15cb of the slinger outer diameter side cylindrical portion 15c due to the relative rotation of the outer diameter member 1 and the inner diameter member 2. The seal lips 13b, 13c shown by the two-dot chain line are in a state before elastic deformation.

[0059] In this embodiment, since the outer diameter member 1 and the inner diameter member 2 have the shapes shown in Fig. 3, the base space 5a has a polygonal shape in cross section as shown in the figure. The additional space 5b is a space that complements the base space 5a, and in the example shown in the figure, has a generally trapezoidal shape in cross section that is narrower than both ends of the base space 5a.

[0060] 3, in the mounted state of the sealing device 10A, an end 15aa of the outer side Ba in the axial direction B of the slinger inner diameter side cylindrical portion 15a, which is located at the end of the inner diameter side Ab in the radial direction A, extends longer toward the outer side Ba in the axial direction B than an end of the outer side Ba in the axial direction B of the cover portion 13d covering the outer peripheral surface 12ab of the core outer diameter side cylindrical portion 12a, which is located at the end of the outer diameter side Aa in the radial direction A. Therefore, the surface of the outer side Ba in the axial direction B of the mounting space 5 (base space 5a) is not parallel to the radial direction A, but is a surface that slopes downward from the inner diameter side Ab to the outer diameter side Aa.

[0061] In the mounting space 5 shown in the drawings, the thickness (depth) dimension (dimension in the axial direction B) of the base space 5a is sufficiently smaller than the dimension in the radial direction A, and the depth dimension of the additional space 5b is also approximately the same as the depth dimension of the base space 5a. Moreover, the dimension in the radial direction A of the additional space 5b is smaller than the dimension in the radial direction A of the base space 5a, and it exists only in a portion corresponding to the middle position in the radial direction A of the base space 5a.

[0062] In this way, the mounting space 5 is a distorted space that narrows toward the inside Bb in the axial direction B, formed by combining two annular narrow spaces of different sizes. However, by configuring the sealing device 10 as shown in the example in the figure, the main parts of the two components can be arranged side by side in the radial direction A of the base space 5a, and the other parts can be arranged in the additional space 5b, which is a complementary space.

[0063] In particular, although the depth dimensions of the base space 5a and the additional space 5b are both small, by overlapping them in the axial direction B, the seal lips 13b, 13c can be aligned along the axial direction B, and can be used as a sliding contact space for the seal lips 13b, 13c.

[0064] In other words, according to this sealing device 10A, even if the mounting space 5 is an uneven space surrounded by the outer diameter member 1, the inner diameter member 2, and the bearing device 8, the seal member 11 and the slinger 15 can be effectively arranged in the mounting space 5, and a sealing structure using a plurality of seal lips 13b, 13c can be achieved. As shown in the figure, by arranging one of the seal lips 13b, 13c in the additional space 5b, the sealing performance can be improved.

[0065] Next, a specific example of the arrangement of the sealing device 10B according to the third embodiment in the mounting space 5 will be described with reference to FIG.

[0066] The sealing device 10B has a seal member 11 made of a core material 12 made of an iron-based material and an elastic member 13 formed integrally with the core material 12, and further includes a slinger 15 made of metal.

[0067] The core material 12 has a generally L-shaped cross section and includes a core material disc portion 12b extending from the outer diameter member 1 side toward the inner diameter member 2 side along the step surface 1d, and a core material inner diameter side cylindrical portion 12c extending from an inner diameter side end portion 12ba of the core material disc portion 12b toward the inner side Bb in the axial direction B along the surface of the step protrusion 1c.

[0068] As shown in FIG. 4, in the mounted state of the sealing device 10B of this embodiment, the core disk portion 12b is disposed within the base space 5a, and the core inner diameter side cylindrical portion 12c is disposed within the additional space 5b.

[0069] The elastic member 13 includes an elastic base 13a arranged to cover an end face 12bc facing the outer diameter side Aa of the core material disc portion 12b in the radial direction A, an outer surface 12bb of the core material disc portion 12b in the axial direction B, an inner peripheral surface 12ca of the core material inner diameter side cylindrical portion 12c, and an end face 12cb of the core material inner diameter side cylindrical portion 12c, and two seal lips 13b, 13c protruding from the inner diameter side end of the elastic base 13a.

[0070] In addition, a cover portion 13d made of an elastic member 13 is arranged to cover the end face 12bc (the outer peripheral surface of the core material 12) of the core material disc portion 12b adjacent to the inner peripheral surface 1a of the outer diameter member 1, and a fitting piece 13db is connected to the outer peripheral portion of the cover portion 13d.

[0071] In this embodiment, a fitting recess 1ba is formed in the step recess 1b of the outer diameter member 1, which is further recessed toward the outer diameter side Aa in the radial direction A, and the sealing member 11 is fitted to the outer diameter member 1 by the fitting piece 13db fitting into the fitting recess 1ba and the core disk portion 12b located further toward the inner diameter side Ab in the radial direction A than the fitting piece 13db.

[0072] Moreover, the core material 12 does not have a core material outer diameter side cylindrical portion 12a (see FIG. 3), and the core material disk portion 12b is located inside the cover portion 13d and is responsible for fitting with the outer diameter member 1. In this illustrated example, the core material 12 and the outer diameter member 1 are made of different materials and have different linear expansion coefficients. Therefore, in consideration of the fact that the fitting force changes over time due to the different linear expansion coefficients, a cover portion 13d made of an elastic member 13 that covers the end face 12bc of the core material disk portion 12b is interposed for the fitting between the seal member 11 and the outer diameter member 1.

[0073] Particularly in this embodiment, the fitting piece 13db of the elastic member 13 is press-fitted into the fitting recess 1ba of the outer diameter member 1, thereby enhancing the fitting force of the seal member 11 to the outer diameter member 1.

[0074] As described above, the slinger 15 includes the slinger inner diameter side cylindrical portion 15a, the slinger ring portion 15b, and the slinger outer diameter side cylindrical portion 15c. The slinger inner diameter side cylindrical portion 15a is fitted to the outer circumferential surface 2a of the rotating shaft 2b serving as the inner diameter member 2.

[0075] More specifically, the slinger ring portion 15b is disposed so as to connect an end portion 15aa of the slinger inner diameter side cylindrical portion 15a on the outside Ba in the axial direction B to an end portion 15cc of the slinger outer diameter side cylindrical portion 15c on the outside Ba in the axial direction B. That is, the slinger 15 is in an inverted U-shape as shown in the figure. The slinger outer diameter side cylindrical portion 15c is longer than the slinger inner diameter side cylindrical portion 15a, and extends to the outer peripheral surface side of the circlip 2c.

[0076] As shown in Figure 4, when the sealing device 10B of this example is installed, the slinger inner diameter side cylindrical portion 15a, the slinger circular ring portion 15b, and a portion of the slinger outer diameter side cylindrical portion 15c are arranged within the base space 5a, and a portion of the inner end 15ca (open end) side of the slinger outer diameter side cylindrical portion 15c within the sealed space is arranged within the additional space 5b.

[0077] As shown in Figure 4, when the sealing device 10B is installed in the installation space 5, the sealing member 11 and the slinger 15 are in a relationship in which the two seal lips 13b, 13c are in contact with the outer peripheral surface 15cb of the slinger outer diameter side cylindrical portion 15c, and due to relative rotation of the outer diameter member 1 and the inner diameter member 2, the two seal lips 13b, 13c are in sliding contact with the outer peripheral surface 15cb of the slinger outer diameter side cylindrical portion 15c.

[0078] In this embodiment, since the outer diameter member 1 and the inner diameter member 2 have the shapes shown in Fig. 4, the base space 5a has a generally rectangular shape (strictly speaking, a polygonal shape) in cross section as shown in the figure. The additional space 5b is a space that complements the base space 5a, and in the example shown in the figure, has a generally parallelogram shape in cross section.

[0079] In the mounting space 5 shown in the drawings, the thickness (depth) dimension (dimension in the axial direction B) of the base space 5a is sufficiently smaller than the dimension in the radial direction A, and the depth dimension of the additional space 5b is even smaller than the depth dimension of the base space 5a. Moreover, the dimension in the radial direction A of the additional space 5b is smaller than the dimension in the radial direction A of the base space 5a, and it exists only in a portion corresponding to the middle position in the radial direction A of the base space 5a.

[0080] In this way, the mounting space 5 is a distorted space that is narrowed toward the inside Bb in the axial direction B by combining two annular flat and narrow spaces of different sizes, but by configuring the sealing device 10B as shown in the figure, the main parts of the two members can be arranged side by side in the radial direction A of the base space 5a, and the other parts can be arranged in the additional space 5b, which is a complementary space. In particular, the additional space 5b can be used as a part of the sliding contact space of the seal lips 13b, 13c.

[0081] In other words, according to this sealing device 10B, even if the mounting space 5 is an uneven space surrounded by the outer diameter member 1, the inner diameter member 2, and the bearing device 8, the seal member 11 and the slinger 15 can be effectively arranged in the mounting space 5, and a sealing structure using a plurality of seal lips 13b, 13c can be achieved. As shown in the figure, by arranging one of the seal lips 13b, 13c in the additional space 5b, the sealing performance can be improved.

[0082] Next, a specific example of the arrangement of the sealing device 10C according to the fourth embodiment in the mounting space 5 will be described with reference to FIG.

[0083] The sealing device 10C has a seal member 11 made of a core material 12 made of an iron-based material and an elastic member 13 formed integrally with the core material 12, and further includes a slinger 15 made of metal.

[0084] The core 12 is generally L-shaped in cross section and includes a core disk portion 12b extending from the outer diameter member 1 side toward the inner diameter member 2 side along the step surface 1d, and a core inner diameter side cylindrical portion 12c extending from an inner diameter side end portion 12ba of the core disk portion 12b toward the inside Bb in the axial direction B along the surface of the step protrusion 1c. This core inner diameter side cylindrical portion 12c fits into the inner circumferential surface 1a of the outer diameter member 1, which corresponds to the surface of the step protrusion 1c.

[0085] As shown in FIG. 5, in the mounted state of the sealing device 10C of this embodiment, the core disk portion 12b is disposed within the base space 5a, and the core inner diameter side cylindrical portion 12c is disposed within the additional space 5b.

[0086] The elastic member 13 includes an elastic base 13a arranged to cover an end face 12bc facing the outer diameter side Aa of the core material disc portion 12b in the radial direction A, an outer surface 12bb of the core material disc portion 12b in the axial direction B, an inner peripheral surface 12ca of the core material inner diameter side cylindrical portion 12c, and an end face 12cb of the core material inner diameter side cylindrical portion 12c, and two seal lips 13b, 13c protruding from the inner diameter side end of the elastic base 13a.

[0087] In this embodiment, the core inner diameter side cylindrical portion 12c is the main member that is responsible for fitting with the outer diameter member 1. However, in this illustrated example, the core 12 and the outer diameter member 1 are made of different materials and have different linear expansion coefficients, so considering that the fitting force changes over time due to the different linear expansion coefficients, a cover portion 13d made of an elastic member 13 that covers the outer peripheral surface 12cc (the outer peripheral surface of the core 12) of the core inner diameter side cylindrical portion 12c that is close to the inner peripheral surface 1a of the outer diameter member 1 is interposed for the fitting between the seal member 11 and the outer diameter member 1.

[0088] Furthermore, an annular protrusion 13da is provided on the outer circumferential surface of the cover portion 13d to improve the fitting force by elastic contact. In Fig. 5, the state of the protrusion 13da before elastic deformation is shown by a two-dot chain line.

[0089] As described above, in this embodiment, unlike the first to third embodiments, the seal member 11 fits onto the inner circumferential surface 1a of the outer diameter member 1 in the additional space 5b.

[0090] As described above, the slinger 15 includes the slinger inner diameter side cylindrical portion 15a, the slinger ring portion 15b, and the slinger outer diameter side cylindrical portion 15c. The slinger inner diameter side cylindrical portion 15a is fitted to the outer circumferential surface 2a of the rotating shaft 2b serving as the inner diameter member 2.

[0091] More specifically, the slinger ring portion 15b is disposed so as to connect an end portion 15aa of the slinger inner diameter side cylindrical portion 15a on the outer side Ba in the axial direction B to an end portion 15cc of the slinger outer diameter side cylindrical portion 15c on the outer side Ba in the axial direction B. That is, the slinger 15 has an inverted U-shape in cross section as shown in the figure. The slinger outer diameter side cylindrical portion 15c is longer than the slinger inner diameter side cylindrical portion 15a, and extends to the outer peripheral surface side of the circlip 2c.

[0092] As shown in Figure 5, in this example, the slinger inner diameter side cylindrical portion 15a, the slinger circular ring portion 15b, and a portion of the slinger outer diameter side cylindrical portion 15c are arranged within the base space 5a, and a portion of the inner end 15ca (open end) side of the slinger outer diameter side cylindrical portion 15c within the sealed space is arranged within the additional space 5b.

[0093] 5, when the sealing device 10 is installed in the installation space 5, the seal member 11 and the slinger 15 are in a relationship in which the two seal lips 13b, 13c contact the outer peripheral surface 15cb of the slinger outer diameter side cylindrical portion 15c, and the two seal lips 13b, 13c come into sliding contact with the outer peripheral surface 15cb of the slinger outer diameter side cylindrical portion 15c due to the relative rotation of the outer diameter member 1 and the inner diameter member 2. The seal lips 13b, 13c shown by the two-dot chain line are in a state before elastic deformation.

[0094] In this embodiment, since the outer diameter member 1 and the inner diameter member 2 have the shapes shown in Fig. 5, the base space 5a has a generally rectangular cross-sectional shape as shown in the figure. The additional space 5b is a space that complements the base space 5a, and in the example shown in the figure, has a generally trapezoidal cross-sectional shape that is narrower than both ends of the base space 5a.

[0095] In the mounting space 5 shown in the drawings, the thickness (depth) dimension (dimension in the axial direction B) of the base space 5a is sufficiently smaller than the dimension in the radial direction A, and the depth dimension of the additional space 5b is also approximately the same as the depth dimension of the base space 5a. Moreover, the dimension in the radial direction A of the additional space 5b is smaller than the dimension in the radial direction A of the base space 5a, and it exists only in a portion corresponding to the middle position in the radial direction A of the base space 5a.

[0096] In this way, the mounting space 5 is a distorted space narrowed toward the inside Bb in the axial direction B by combining two annular narrow spaces of different sizes, but by configuring the sealing device 10 as shown in the figure, the main parts of the two members can be arranged side by side in the radial direction A of the base space 5a, and the other parts can be arranged in the additional space 5b, which is a complementary space. In particular, the additional space 5b can be used as a part of the sliding contact space of the seal lips 13b, 13c.

[0097] In other words, according to this sealing device 10C, even if the mounting space 5 is an uneven space surrounded by the outer diameter member 1, the inner diameter member 2, and the bearing device 8, the seal member 11 and the slinger 15 can be effectively arranged in the mounting space 5, and a sealing structure using a plurality of seal lips 13b, 13c can be achieved. As shown in the figure, by arranging one of the seal lips 13b, 13c in the additional space 5b, the sealing performance can be improved.

[0098] As described above, in each of the sealing devices 10, 10A, 10B, and 10C of the four embodiments, the sealing structure is formed by the seal lips 13b and 13c by adding the additional space 5b, which is a small space, to the base space 5a.

[0099] To achieve such a sealing structure, in all of the sealing devices 10, 10A, 10B, and 10C of the embodiments, the slinger outer diameter side cylindrical portion 15c is lengthened and extended to the depth of the sealed space 4, and the seal lips 13b, 13c are also disposed deep within the sealed space 4 so as to match the extended slinger outer diameter side cylindrical portion 15c. In this way, the sliding structure of the seal lips 13b, 13c can be disposed in the narrow additional space 5b.

[0100] Both of the two seal lips 13b, 13c may be disposed in the additional space 5b, or only the seal lip 13c located on the inner side Bb in the axial direction B may be disposed in the additional space 5b.

[0101] Furthermore, in the four embodiments, a cover portion 13d made of an elastic material (elastic member 13) is used as the fitting contact portion of the sealing member 11 with the housing 1, thereby preventing direct contact between the housing 1 and the core material 12, thereby preventing the fitting force from changing over time due to different linear expansion coefficients.

[0102] In other words, in order to construct a lightweight electric assisted bicycle, such a fitting structure allows the housing 1 to be made of lighter non-ferrous metals such as alloy magnesium and aluminum, or synthetic resins. In any embodiment, the cover portion 13d is formed with the protrusion 13da or the fitting piece 13db, so that a strong fitting force due to the elastic contact force can be obtained even in the extremely thin and narrow base space 5a or additional space 5b. In particular, in the case of FIG. 4, the fitting between the fitting piece 13db and the fitting recess 1ba plays a part of the fitting between the seal member 11 and the outer diameter member 1, so that the sealing device 10C can be attached more firmly.

[0103] In addition, the arrangement of the sealing devices 10, 10A, 10B, and 10C relative to the base space 5a and the additional space 5b is not limited to the four examples shown in the drawings, and various arrangements are possible. It is sufficient that the additional space 5b is at least a part of the area in which the seal lips 13b and 13c slide against the slinger 15.

[0104] It is needless to say that the sealing devices 10, 10A, 10B, and 10C according to the embodiments described above are merely examples, and that the configurations and shapes can be appropriately changed to those of the examples shown in the drawings. The fitting structure of the seal member 11 of the sealing devices 10, 10A, 10B, and 10C may be a fitting structure on either the base space 5a side or the additional space 5b side, as in the above embodiment.

[0105] Furthermore, the sealing devices 10, 10A, 10B, and 10C described above are mounted on the bearing device 8 that is installed inside the drive unit of an electrically assisted bicycle, but are not limited to this and can be applied to various types of bearing devices 8.

[0106] Furthermore, the mounting space 5 in which the sealing devices 10, 10A, 10B, and 10C are mounted is not limited to the space outside the bearing device 8 as in the above embodiment, but may be a space provided in the internal space 6 of the bearing device 8, and may be a stepped space formed at least by the base space 5a and the additional space 5b. [Explanation of symbols]

[0107] 1 Outer diameter member (housing) 1a Inner surface 1b Step recess 1ba Recessed portion for mating 1c Step convex part 1d step surface 2 Inner diameter member 2a Outer surface 2b Rotation axis 2c Circlip 4 Sealed Space 5. Installation space 5a Base Space 5b Additional space 6 Space inside the device 8 Bearing device 8a Outer ring member 8b Inner ring member 8c Rolling elements 8d, 8e aperture 10, 10A, 10B, 10C Sealing device 11 Sealing material 12 Core material 12a: Core outer diameter side cylindrical part 12aa: Axial inner end of the cylindrical portion on the outer diameter side of the core material 12ab Outer circumferential surface of the cylindrical portion on the outer diameter side of the core material 12ac: Inner surface of the cylindrical part on the outer diameter side of the core material 12b Core disc section 12ba Inner diameter side end of core disc 12bb: Axial outer surface of the core disc 12bc Radial end face of the core disc 12c Inner diameter cylindrical part of core 12ca Inner surface of the cylindrical part on the inner diameter side of the core 12cb End face of the cylindrical part on the inner diameter side of the core material 13 Elastic member 13a Elastic base 13b, 13c Seal lip 13d Cover 13da protrusion 13db mating piece 15 Slinger 15a Slinger inner diameter side cylindrical part 15aa Axial outer end of the cylindrical portion of the slinger 15ab Axial inner end of the cylindrical portion of the slinger 15b Slinger ring part 15ba End of the outer diameter side of the slinger ring 15c Slinger outer diameter cylindrical part 15ca The inner end of the sealed space of the cylindrical outer diameter side of the slinger 15cb Outer surface of the cylindrical part on the outer diameter side of the slinger 15cc Slinger outer diameter cylindrical part axial outer end A Radial direction Aa Radial outer side Ab Radial inner side B Axial direction Ba: Outer axial direction Bb Axial inner side

Claims

1. A sealing device that seals a space between an outer diameter member and an inner diameter member that rotate relative to each other, the sealing device comprising a seal member and a slinger, the sealed space includes a base space that is a main arrangement space of the sealing device, and an additional space that communicates with the base space along the axial direction toward the back of the sealed space and narrows in a stepped manner from both ends of the base space in the radial direction, the seal member is made of a core material and an elastic member integrally provided with the core material, and includes a plurality of seal lips made of the elastic member, and is configured to fit into an inner peripheral surface of the outer diameter member, the slinger comprises a slinger inner diameter side cylindrical portion which fits onto the outer peripheral surface of the inner diameter member on the base space side, a slinger ring portion which extends from an end of the slinger inner diameter side cylindrical portion to the outer diameter side, and a slinger outer diameter side cylindrical portion which extends from an end of the slinger ring portion to the depth of the sealed space along the axial direction, and the depth end of the slinger outer diameter side cylindrical portion within the sealed space is disposed in the additional space, A sealing device characterized in that the plurality of seal lips are arranged so as to contact an outer peripheral surface of the outer diameter side cylindrical portion of the slinger.

2. In claim 1, A sealing device, characterized in that at least one of the plurality of seal lips is disposed in the additional space.

3. In claim 1, A sealing device characterized in that the slinger is shaped so that the axial length dimension of the slinger outer diameter side cylindrical portion is greater than the axial length dimension of the slinger inner diameter side cylindrical portion.

4. In claim 1, The core member and the outer diameter member are formed of different materials, the sealing member includes a cover portion that covers an outer peripheral surface of the core material adjacent to the inner peripheral surface of the outer diameter member with the elastic member, A sealing device characterized in that the cover portion fits and contacts the outer diameter member in the base space or the additional space.

5. In claim 4, A sealing device characterized in that a fitting recess is formed on the inner peripheral surface of the outer diameter member, and a fitting piece that fits into the fitting recess is formed on the cover portion.

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