sealing device

Abstract

The present invention provides a sealing device that uses a U-shaped slinger and can achieve both torque reduction and improved sealing performance. [Solution] The core material portion 30A of the sealing device 10 is equipped with a seal lip portion 35 made of an elastic material that rotates relative to the slinger 20A while in contact with it. The slinger 20A is equipped with a first cylindrical portion 22, a disc portion 21, and a second cylindrical portion 23, and has a recessed space 24 with the first cylindrical portion 22, the disc portion 21, and the second cylindrical portion 23 forming the outer frame. At least two continuous surfaces facing the recessed space 24, namely a first surface 25a corresponding to the disc portion and a second surface 25b adjacent to the first surface 25a, are roughened.

Description

Technical Field

[0001] The present invention relates to a sealing device having a seal lip portion made of an elastic material that rotates relative to a slinger while making contact therewith.

Background Art

[0002] Conventionally, in a case where a lip piece of a seal lip portion elastically contacts (slides against) an L-shaped slinger, various techniques have been proposed for roughening the L-shaped inner surface of the slinger where the lip piece may come into contact in order to reduce torque (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, generally, in order to improve the sealing performance of a sealing device, it is considered appropriate to use a U-shaped slinger.

[0005] Therefore, by using a U-shaped slinger and appropriately roughening the lip sliding contact surface of the slinger, it is possible to achieve both reduction of torque and improvement of sealing performance. However, such a sealing device has not been proposed conventionally.

[0006] The present invention has been proposed in view of the above circumstances, and an object thereof is to provide a sealing device that can achieve both reduction of torque and improvement of sealing performance in a sealing device using a U-shaped slinger.

Means for Solving the Problems

[0007] To achieve the above objective, the present invention provides an annular sealing device configured to seal the space between two members, comprising a core material portion fitted and fixed to one of two members that rotate concentrically relative to each other, and a slinger fitted and fixed to the other member, wherein the core material portion includes a seal lip portion made of an elastic material that rotates relative to the slinger while in contact with it, and the slinger comprises a first cylindrical portion for fitting, a disc portion, and a second cylindrical portion, and has a recessed space with the first cylindrical portion, the disc portion, and the second cylindrical portion forming an outer frame, and is characterized in that two continuous surfaces facing the recessed space, namely a first surface corresponding to the disc portion and a second surface adjacent to the first surface, are roughened. [Effects of the Invention]

[0008] Since the sealing device of the present invention has the configuration described above, it is possible to achieve both torque reduction and improved sealing performance in a sealing device using a U-shaped slinger. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic longitudinal cross-sectional view of a bearing device including a sealing device according to an embodiment of the present invention. [Figure 2] Figure 1 is an enlarged view of section X, where (a) and (b) are schematic cross-sectional end views of sealing devices relating to two different usage modes in which slingers of the same shape are used. [Figure 3] (a) and (b) are schematic partial longitudinal cross-sectional views showing two aspects of the projection step of the projection material onto the slinger body. [Figure 4] The figures and tables show the test results of one embodiment of the sealing device of the present invention, where (a) is a schematic cross-section end view of the slinger body, and (b), (c), and (d) are tables showing the test results. [Figure 5] (a) to (c) are schematic cross-sectional end views of a slinger body used in a sealing device according to another embodiment of the present invention. [Figure 6] (a) and (b) are schematic end views of a slinger body used in a sealing device according to another embodiment of the present invention. [Modes for carrying out the invention]

[0010] The sealing device according to an embodiment of the present invention will be described below with reference to Figures 1 to 6 of the attached drawings.

[0011] First, the basic configuration of the bearing device 1 to which the sealing devices 10 and 11 are mounted will be described based on Figure 1. In this specification, as shown in Figure 1, the side facing the wheel (not shown) along the rotation axis L direction (hereinafter abbreviated as the axial direction) (the side facing left in Figure 1) is called the wheel side, and the side facing the vehicle body (not shown) (the side facing right in Figure 1) is called the vehicle body side.

[0012] In the bearing device 1 shown in Figure 1, an outer ring member 2 is fixed to the vehicle body (not shown), two rows of rolling elements 7 are arranged inside it, and further inside these, a hub ring 3b and an inner ring 3a are supported so as to be rotatable around the axis. The hub ring 3b has a hub flange 3c, and a drive wheel (not shown) is attached to the hub flange 3c by bolts 3d and nuts (not shown).

[0013] Furthermore, the drive shaft 4 is coaxially spline-fitted to the hub wheel 3b, and the drive shaft 4 is connected to a drive source (not shown) via a constant velocity joint 5. The drive shaft 4 is integrated with the hub wheel 3b by a nut 4a, preventing the hub wheel 3b from coming off the drive shaft 4.

[0014] The inner ring member 3 is composed of a hub ring 3b and an inner ring 3a. This inner ring member 3 is capable of relative rotation with respect to the outer ring member 2 around the rotation axis L. Rolling elements 7 are interposed between the inner ring member 3 and the outer ring member 2, held in place by a retainer 7a.

[0015] Thus, the outer ring member 2 and the inner ring member 3 form two members that rotate relative to each other, and an annular space is formed between these two members, which is the space containing the interposed portion of the rolling element 7. This annular space is the bearing space and is designated as the sealed space 6.

[0016] A sealing device 10 is mounted on the body side end in the axial direction of the sealed space 6. Further, another sealing device 11 is mounted on the wheel side end of the sealed space 6. By mounting the sealing devices 10 and 11 on each of both ends in this way, both ends along the axial direction of the sealed space 6 are sealed.

[0017] The sealed space 6 is filled with a lubricant (not shown) such as grease, whereby the rolling of the rolling elements 7 is made smooth. The sealing devices 10 and 11 have a function of preventing external leakage of this lubricant and preventing the intrusion of muddy water and dust etc. from the outside into the sealed space 6, and a function of discharging the intruded muddy water etc.

[0018] Also, an annular magnetic encoder (annular magnet 27) (see FIG. 2) is arranged on the body side surface of the slinger 20A of the sealing device 10 mounted on the body side, and a magnetic sensor 15 is installed on the body at a position facing the annular magnet 27. Note that the slinger 20A may not have the annular magnet 27.

[0019] The annular magnet 27 is an elastic member formed integrally with a slinger 20A (slinger body 20) described later, obtained by kneading magnetic powder into a rubber material, and having a large number of N poles and S poles alternately magnetized along its circumferential direction. The magnetic sensor 15 detects a magnetic change accompanying the rotation of the annular magnet 27. That is, the magnetic sensor 15 and the annular magnet 27 constitute a rotation detection mechanism for the wheel (inner wheel member 3), and an anti-lock braking system is constituted.

[0020] Next, the sealing device 10 (on the body side) according to the present embodiment will be described while referring to FIGS. 2(a) and (b). First, the schematic basic configuration of the sealing device 10 will be described.

[0021] This sealing device 10 includes a core member portion 30A fitted and fixed to one of two members that rotate relatively concentrically, and a slinger 20A fitted and fixed to the other member, and is an annular sealing device 10 configured to seal between the two members.

[0022] The core material portion 30A is equipped with a seal lip portion 35 made of an elastic material that rotates relative to the slinger 20A while in contact with it.

[0023] The slinger 20A comprises a first cylindrical portion 22, a disc portion 21, and a second cylindrical portion 23, and has a recessed space 24 with the first cylindrical portion 22, the disc portion 21, and the second cylindrical portion 23 forming an outer frame. At least two continuous surfaces facing the recessed space 24, namely a first surface 25a corresponding to the disc portion 21 and a second surface 25b adjacent to the first surface 25a, are roughened.

[0024] In the example of this embodiment described below, one of the two members that rotate concentrically relative to the other is the fixed outer ring member 2, and the other is the rotating inner ring member 3.

[0025] Furthermore, the inner surface 25 of the slinger 20A also includes a third surface 25c that faces the recessed space 24 and corresponds to the second cylindrical portion 23.

[0026] Next, we will explain in detail the two examples of sealing devices 10 shown in Figures 2(a) and 2(b). First, we will explain the common features of the sealing devices 10 in Figures 2(a) and 2(b).

[0027] In each of these sealing devices 10, the slinger 20A is fitted and fixed to the inner ring member 3, and the core material 30A is fitted and fixed to the outer ring member 2. Both the slinger 20A and the core material 30A are annular in shape, with the slinger 20A having a U-shaped radial cut end face and the core material 30A having an L-shaped radial cut end face, and these members are mounted in the sealed space 6 of the bearing device 1 so as to face each other.

[0028] The slinger 20A comprises a slinger body 20 made of metal and the aforementioned annular magnet 27 that constitutes the magnetic encoder.

[0029] The slinger body 20 includes a first cylindrical portion 22 that fits onto the inner ring member 3, a disc portion 21 that extends radially outward from the axial outer end of the first cylindrical portion 22, and a second cylindrical portion 23 that extends axially inward from the radial outer end of the disc portion 21.

[0030] The recessed space 24 is an annular space surrounded by the first cylindrical portion 22, the disc portion 21, and the second cylindrical portion 23. The slinger body 20 may be made of a hard synthetic resin material.

[0031] Furthermore, while there is no particular concern regarding the relative protrusion dimensions of the first cylindrical portion 22 and the second cylindrical portion 23 from the disc portion 21, considering that the first cylindrical portion 22 is a fitting part, that the slinger 20A is combined with the core material portion 30A as shown in Figure 2, and that the surface roughening method described later in Figure 3 is used during the manufacturing stage of the slinger 20A, it is desirable to make the protrusion dimension of the first cylindrical portion 22 larger and the protrusion dimension of the second cylindrical portion 23 smaller, as shown in the example figure.

[0032] Of the inner surface 25 of the slinger 20A, the first surface 25a is the axial inner surface of the disc portion 21, the second surface 25b is the radial outer surface of the first cylindrical portion 22, and the third surface 25c is the radial inner surface of the second cylindrical portion 23, and these three surfaces face the recessed space 24.

[0033] The annular magnet 27 is fixed to the disc portion 21 and the second cylindrical portion 23 so as to cover substantially the entire outer surface (vehicle body side) of both the disc portion 21 and the second cylindrical portion 23. The magnetic sensor 15 is positioned to face the disc portion 21 of the annular magnet 27.

[0034] The core material portion 30A is formed by fixing and integrating a seal lip portion 35 made of an elastic material such as rubber to a core body 30 made of metal. The core body 30 includes a core body cylindrical portion 32 that fits into the outer ring member 2, and a core body disc portion 31 that extends radially inward from the axial inner end of the core body cylindrical portion 32. The core body 30 may be made of a hard synthetic resin material.

[0035] The seal lip portion 35 comprises a seal body portion 35a fixed to the entire surface of the inner corner between the core cylindrical portion 32 and the core disc portion 31, a first lip piece 35b constituting an axial lip, and a second lip piece 35c constituting a radial lip. The seal body portion 35a is fixed to the radial inner end 31a of the core disc portion 31 so as to wrap around to the outer surface (inner surface in the axial direction) of the core disc portion 31, and is also fixed to the radial outer end 32a of the axial outer portion 32 so as to wrap around to the outer surface in the axial direction.

[0036] The first lip piece 35b protrudes inclined toward the first surface 25a from the core disc portion 31 side so that its diameter increases and it is directed outward in the axial direction, while the second lip piece 35c protrudes inclined toward the second surface 25b from the core disc portion 31 side so that its diameter decreases and it is directed inward in the axial direction.

[0037] In Figure 2(a), when the sealing device 10 is installed in the sealed space 6 of the bearing device 1, the first lip piece 35b elastically contacts the first surface 25a, while the second lip piece 35c does not contact the second surface 25b. The diagram of the first lip piece 35b shown by the dashed line is a state diagram before elastic deformation.

[0038] In Figure 2(b), when the sealing device 10 is installed in the sealed space 6 of the bearing device 1, the first lip piece 35b is not in contact with the first surface 25a, while the second lip piece 35c elastically contacts the second surface 25b. The diagram of the second lip piece 35c shown by the dashed line is a state diagram before elastic deformation.

[0039] In this embodiment, in both of these two types of sealing devices 10, the two continuous surfaces, the first surface 25a and the second surface 25b, are roughened. Specifically, substantially the entire surface of these two continuous surfaces, including the first inner corner portion 25d which is the inner corner of both surfaces, is continuously roughened. Furthermore, it is desirable that the second inner corner portion 25e, which is the inner corner of the first surface 25a and the third surface 25c, is also roughened.

[0040] Generally, when lip pieces 35b and 35c slide against the slinger 20A by elastic contact, a higher degree of contact necessitates an increase in the torque required to rotate the rotating member. Therefore, in order to avoid an increase in torque, it is desirable to roughen the first surface 25a and the second surface 25b of the slinger 20A to avoid so-called full contact between the lip pieces 35b and 35c and the slinger 20A, thereby reducing the degree of contact.

[0041] Since the roughened surface is used for this purpose, it is desirable that the roughening is continuous in the circumferential direction on the continuous first surface 25a and second surface 25b. Furthermore, it is desirable that the roughening is continuous in the radial direction on the first surface 25a and continuous in the axial direction on the second surface 25b.

[0042] Furthermore, the roughened surface may be constructed with an uneven pattern such as a pearlescent finish, meaning that the recessed and raised portions may be discontinuous. However, it goes without saying that the areas in contact with the lip pieces 35b and 35c must not be smooth.

[0043] According to the slinger 20A of this embodiment, since the roughened portion of the slinger 20A extends over a wide area on two continuous surfaces, various shapes and specifications of core material portion 30A (especially lip pieces 35b and 35c of the seal lip portion 35) can be combined with the slinger 20A.

[0044] In other words, this slinger 20A can correspond to a core material portion 30A having various lip pieces 35b, 35c, including the two examples shown in Figures 2(a) and 2(b). In such a slinger 20A, the first inner corner portion 25d can also be a contact position for the lip pieces 35b, 35c.

[0045] In short, if substantially the entire surface of the first surface 25a and substantially the entire surface of the second surface 25b are roughened, the contact position of the first lip piece 35b can be made to correspond to any radial position on the first surface 25a, and the contact position of the second lip piece 35c can be made to correspond to any axial position on the second surface 25b.

[0046] Furthermore, in this embodiment, a wider area of ​​the surface is roughened, including the second inner corner portion 25e, so a first lip piece 35b that contacts the second inner corner portion 25e can also be provided.

[0047] Furthermore, if the first surface 25a and the second surface 25b contain areas that are not roughened, this could lead to an increase in torque. However, since almost the entire surface of both the first surface 25a and the second surface 25b is roughened, an increase in torque can be suppressed.

[0048] Furthermore, even when both the first lip piece 35b and the second lip piece 35c are for sliding contact, the roughened surface prevents so-called "smooth contact" with either lip piece 35b or 35c. This also prevents the internal pressure balance from being disrupted, such as the closed space formed by the slinger 20A, the first lip piece 35b, and the second lip piece 35c becoming negatively pressurized.

[0049] The degree of roughening of the first surface 25a and the second surface 25b is preferably such that the arithmetic mean roughness Ra, which is an indicator of surface roughness, is 0.4 or higher and 0.9 or lower, as determined by various tests conducted by the inventors.

[0050] Next, a method for manufacturing a sealing device, including a method for roughening the surface of the slinger 20A, will be described. First, the basic procedure of the manufacturing method according to this embodiment will be described with reference to Figures 3(a) and 3(b).

[0051] This manufacturing method includes at least a surface treatment step involving the impact of a projectile 41 (shown as a dashed line with an arrow in Figures 3(a) and 3(b)) on the slinger 20A (slinger body 20).

[0052] As described above in Figure 2, the sealing device 10 has a core material portion 30A which is equipped with a seal lip portion 35 made of an elastic material that rotates relative to the slinger 20A in contact with or without contact with it, and the slinger 20A is equipped with a first cylindrical portion 22 and a disc portion 21 which are responsible for fitting into either of the two members (outer ring member 2 and inner ring member 3), and is equipped with a recessed space 24 opposite to the core material portion 30A, with the first cylindrical portion 22 and the disc portion 21 forming the outer frame.

[0053] The surface treatment step involves projecting the projection material 41 onto the surface of the slinger 20A on the side of the recessed space 24 at different projection angles.

[0054] Next, the detailed procedure of the surface treatment step in the manufacturing method according to this embodiment will be explained with reference to Figures 3(a)(b) and 4. In the example of Figures 3(a)(b), the procedure is to perform multiple types of projection steps, and two types of projection steps are listed as the first projection step and the second projection step.

[0055] In this surface treatment step, a method for roughening the surface of the slinger 20A (slinger body 20) using the abrasive material 41 is, for example, shot blasting (including shot peening). In this surface roughening method, a projection device 40 is used to project the abrasive material 41 onto the target surface.

[0056] Various materials such as metals and ceramics can be used as the projection material 41, and its shape can be spherical particles or powders, and it can also be of various sizes. Examples of projection devices 40 include mechanical, pneumatic, and wet types. As shown in Figures 3(a) and 3(b), the projection device 40 is capable of projecting the projection material 41 from various directions at a predetermined projection speed.

[0057] The roughening of the slinger body 20 by projecting the projection material 41 is mainly performed on the first surface 25a and the second surface 25b, and the projection device 40 can be installed and used at an appropriate position so that the projection material 41 can be projected in various directions. Needless to say, the area of ​​the target surface that the projection material 41 projected from the projection device 40 collides with will vary depending on the range of the projection angle and the distance from the projection device 40 to the target surface.

[0058] Furthermore, since the roughening is performed mainly on the first surface 25a and the second surface 25b of the slinger body 20, it is desirable that the surface treatment step be performed as shown in Figure 3, with the slinger body 20 placed on the workbench 45 with the outer surface of the disc portion 21 facing downwards and the recessed space 24 facing upwards. Although Figure 3 shows an example of working on the slinger body 20 before the annular magnet 27 is fixed, the work may also be performed on the slinger 20A after the annular magnet 27 has been fixed.

[0059] Furthermore, the surface treatment step (roughening method) is a procedure that combines a first projection step (see Figure 3(a)) and a second projection step (see Figure 3(b)). In this roughening method, as shown in these figures, the projection device 40 is installed in two positions relative to the slinger body 20 (the first surface 25a and the second surface 25b).

[0060] Thus, in this surface treatment step, the positional relationship between the slinger body 20 and the projection device 40 changes as the first projection step and the second projection step are executed sequentially.

[0061] Furthermore, since the slinger body 20 is an annular shape, the first surface 25a and the second surface 25b need to be roughened over their entire circumferential surface, and the relative positional relationship between the slinger body 20 and the projection device 40 needs to be variable.

[0062] To achieve this, the projection device 40 may be fixed and the projection material 41 may be projected while the slinger body 20 is rotated around its central axis, or the slinger body 20 may be fixed and the projection device 40 may be rotated around the central axis of the slinger body 20 while the projection material 41 is projected.

[0063] Next, the first projection step and the second projection step, which are substeps in the surface treatment step, will be explained individually.

[0064] In this surface treatment step, it is necessary to perform both the first projection step and the second projection step, but either one may be performed first. Furthermore, after performing both projection steps, it may be decided to perform one or both projection steps again based on the quality of the surface roughening. Alternatively, both projection steps may be performed simultaneously.

[0065] The first projection step, as shown in Figure 3(a), involves projecting the projection material 41 toward the first inner corner 25d and its vicinity (near the first cylindrical portion and the disc portion) from a position opposite the recessed space 24 side of the second surface 25b at an angle of 10 degrees or more and 40 degrees or less with respect to the radial direction of the first surface 25a.

[0066] In other words, the projection device 40 should be installed facing the inner portion of the first cylindrical portion 22 of the slinger body 20, rather than the outer portion, and tilted within the range of the upper and lower limit angles.

[0067] While it is desirable for the projection angle to be within the upper and lower limit angles, it can be determined by considering various conditions, namely the protruding dimensions of the first cylindrical portion 22, the protruding dimensions of the second cylindrical portion 23, the radial dimensions of the disc portion 21, the specifications of the projection device 40, and the installation height of the projection device 40. Therefore, it is permissible for the projection angle to be outside the upper and lower limit angles.

[0068] As mentioned above, as shown in Figure 3(a), the projection dimension of the second cylindrical portion 23 from the disc portion 21 is smaller than the projection dimension of the first cylindrical portion 22. Therefore, the projection device 40 should be installed so that the projection material 41 projected from the projection device 40 passes above the open end of the second cylindrical portion 23. By doing so, collisions between the projection material 41 and the outer surface of the second cylindrical portion 23 can be suppressed, thereby reducing waste of projection material 41.

[0069] In the first projection step, it is desirable to adjust the projection material 41 so that it directly collides with the first inner corner 25d, substantially the entire surface of the second surface 25b, and a portion of the first surface 25a on the side of the first inner corner 25d, taking the above conditions into consideration.

[0070] The second projection step, as shown in Figure 3(b), involves projecting the projection material 41 toward the first surface 25a at an angle of 80 degrees or more and 100 degrees or less with respect to the radial direction of the first surface 25a, preferably approximately 90 degrees. The installation height of the projection device 40 can be adjusted considering the degree of spread of the projection material 41 and the radial length of the disc portion 21 of the projection device 40.

[0071] The projection angle is preferably within the upper and lower limit angles, as in the first projection step. However, it can be determined by considering various conditions, namely the protrusion dimension of the first cylindrical portion 22, the protrusion dimension of the second cylindrical portion 23, the radial length dimension of the disc portion 21, the specifications of the projection device 40, and the installation height of the projection device 40. Therefore, it may be outside the upper and lower limit angles.

[0072] In the second projection step, it is desirable to adjust the projection material 41 so as to collide with substantially the entire surface of the first surface 25a, the first inner corner 25d, at least the lower part of the second surface 25b, the second inner corner 25e, and at least the lower part of the third surface 25c, taking the above conditions into consideration.

[0073] Furthermore, tests have revealed that in both the first and second projection steps, if each projection step is performed for a certain period of time, the projection materials 41 projected at different times may collide with each other. For example, in the same projection step, a projection material 41 that was projected earlier, hit the inner surface 25, and bounced back may collide with a projection material 41 that was projected later, causing the colliding projection materials 41 to change direction and hit various parts. Of course, there is also the possibility that the projection material 41 may bounce back from hitting the inner surface 25 and hit other inner surfaces 25 again.

[0074] Furthermore, in order to achieve an appropriate surface roughness, that is, an arithmetic mean roughness Ra of 0.4 or higher and 0.9 or lower, the projection time and projection speed of the first and second projection steps should be appropriately changed and adjusted so that the arithmetic mean roughness Ra falls within these ranges, thereby determining the projection time and projection speed necessary to obtain a suitable slinger body 20.

[0075] By combining the first and second projection steps in this manner, the inner surface 25 of the slinger 20A, where the lip pieces 35b and 35c slide against each other, can be roughened over a wide area. Regardless of the shape and specifications of the seal lip portion 35 of the core material portion 30A combined with the slinger 20A, a wide area of ​​the inner surface 25 of the slinger 20A can be roughened, thus improving the design flexibility of the sealing device 10.

[0076] While three or more types of projection steps may be combined, it is desirable to include at least one projection step such as a first projection step in which the projection device 40 is tilted to project the projection material 41 diagonally toward the vicinity of the first inner corner 25d. Furthermore, a projection step in which projection occurs from the radially inner side toward the second inner corner 25e on the outer side may also be included.

[0077] Furthermore, it has been found that this surface roughening method roughens a wide area of ​​the inner surface 25 of the slinger 20A fairly uniformly. This uniformity also facilitates the flexible design of the sealing device 10.

[0078] Furthermore, this surface roughening method allows for uniform roughening of a wider surface area simply by combining the first and second projection steps. This suppresses the need for further various processes to achieve uniformity, thereby enabling the efficient manufacture of the slinger 20A.

[0079] Furthermore, even if the contact positions of the lip pieces 35b and 35c with respect to the slinger body 20 are not as expected when mounting the sealing device 10 to the bearing device 1, if the roughening of the inner surface 25 of the slinger body 20 is uniform, the possibility of the unexpected contact position causing a change in rotational torque is low. Therefore, adjustments during the mounting of the sealing device 10 and replacement of the slinger 20A can be suppressed, enabling efficient work.

[0080] Furthermore, even if the slinger 20A is U-shaped, as in the sealing device 10 of this embodiment, the first and second projection steps can be carried out without any problems. Since the first projection step is carried out with the projection device 40 tilted, there is a possibility that the projection material 41 will not collide with a part of the first surface 25a, but since the second projection step is also carried out, the parts that are not roughened in the first projection step can be supplemented by the second projection step.

[0081] In particular, tests have shown that the outer portion of the first surface 25a and the vicinity of the second inner corner 25e of the inner surface 25 of the slinger 20A, which were previously considered the most difficult to roughen, can now be roughened to the same extent as the inner and central portions of the first surface 25a.

[0082] Regarding broad surface roughening and its uniformity, the inventors performed a combination of the first and second projection steps as an example, and measured the surface roughness (arithmetic mean roughness Ra) of the first surface 25a and the second surface 25b of the roughened inner surface 25 of the slinger body 20 using a surface roughness measuring instrument (not shown). Comparative tests were also conducted on comparative examples to the example, and the arithmetic mean roughness Ra was measured.

[0083] Specifically, the number of test subjects (number of Slinger 83 sheets) for both the example and comparative example was set to 30, and tests were conducted on the first surface 25a and the second surface 25b at the following projection angles, and the average value of the arithmetic mean roughness Ra was calculated. <Projection angle> Example: Projection at a 90-degree projection angle (second projection step) and projection at a 30-degree projection angle (first projection step) were performed. Comparative example: Two projections were performed at a projection angle of 45 degrees.

[0084] In both the examples and comparative examples, the arithmetic mean roughness Ra was measured on the first surface 25a and the second surface 25b of the roughened slinger body 20 by operating the inspection needle of a measuring instrument (Surface Recorder SE3500, manufactured by Kosaka Research Institute Co., Ltd.) under the following measurement conditions. The direction of operation of the inspection needle was circumferential for both the first surface 25a and the second surface 25b. <Measurement method / conditions> The measurement method and conditions conformed to the standard "JIS B 0601:2001" for evaluating surface roughness. The specific conditions are: Measurement length for arithmetic mean roughness Ra: 2.4 mm (approximately 10% of the circumferential length) Measurement speed of the test needle: 0.1 mm / sec It is said that... The test and measurement results will be explained with reference to Figures 4(a) to 4(d).

[0085] For circumferential measurements of the first surface 25a, appropriate measurement points were selected from the inner A, central B, and outer C regions shown in Figure 4(a) within a suitable arc in the circumferential direction. At these measurement points, the inspection needle was moved linearly, generally following the circumferential direction.

[0086] The inner part A, central part B, and outer part C shown in Figure 4(a) are three virtual regions formed by dividing the radial length dimension of the first surface 25a into three substantially equal parts. The central part B and outer part C are the main regions that the first lip piece 35b may contact or come into close proximity with in the sealing device 10 shown in Figures 2(a) and 2(b).

[0087] Furthermore, for the circumferential inspection of the second surface 25b, an appropriate measurement point was selected in a suitable arc section in the circumferential direction (which may be the same arc section as the first surface 25a), and the inspection needle was moved to generally follow the circumferential direction at that measurement point. The measurement points in this test were selected from the axial region D, which is the area in contact with or adjacent to the second lip piece 35c (see Figure 4(a)).

[0088] In both the examples and comparative examples, the arithmetic mean roughness Ra was measured at three locations on the first surface 25a and one location on the second surface 25b. This was repeated for n sheets (30 sheets), and the average value for the n sheets was calculated.

[0089] Next, we calculated the ratio (relative value) of the arithmetic mean roughness Ra of each part (inner part A, central part B, outer part C, region D) to the arithmetic mean roughness Ra of central part B. In other words, we calculated (arithmetic mean roughness Ra of each part) / (arithmetic mean roughness Ra of central part B).

[0090] In short, regarding surface roughening in the examples, instead of comparing the absolute values ​​of the arithmetic mean roughness Ra, the relative values ​​of the arithmetic mean roughness Ra of each part were calculated, with the arithmetic mean roughness Ra of the central part B set as the baseline value of 1.0. Various comparisons were then made to evaluate and judge the results.

[0091] The table in Figure 4(b) shows the relative values ​​for each part in an example where the surface treatment was performed in the order of a second projection step (90 degrees) followed by a first projection step (30 degrees). The table in Figure 4(c) shows the relative values ​​for each part in a comparative example where the surface treatment was performed by two projections at 45 degrees.

[0092] In the example, the relative values ​​for each part were a minimum of 0.91 (inner part A) and a maximum of 1.04 (outer part C, area D), while in the comparative example, the relative values ​​for each part were a minimum of 0.69 (outer part C) and a maximum of 1 (central part B) (see Figures 4(b) and 4(c)). As can be seen from these relative values, the example is judged and evaluated as having achieved greater uniformity compared to the comparative example.

[0093] In particular, the outer part C and region D show significant improvement compared to the conventional surface roughening method (comparative example), as is clear from the values ​​in Figure 4(d). Figure 4(d) shows the ratio of the example to the comparative example for the arithmetic mean roughness Ra in each part, i.e., the example / comparative example ratio. As can be seen from this relative value table, the relative value for the outer part C is 1.30, indicating an improvement in the degree of surface roughening of the outer part C, and the relative value for region D is 1.25, indicating an improvement in the degree of surface roughening of region D.

[0094] The inventors also noted that the relative value of the outer part C, which was previously considered difficult to roughen, was greater than the relative value of the inner part A (see Figure 4(b)), and determined that a difference of 0.25 or less was the acceptable criterion for roughening the outer part C. If the difference exceeded 0.25, it was deemed inadequate for uniformity and was rejected.

[0095] The inventors also determined that the relative value of region D (second surface 25b) being greater than the relative value of inner portion A is a criterion for acceptance regarding the roughening of region D (second surface 25b). In particular, it is desirable that the relative value of region D be between 0.85 and 1.15.

[0096] As can be seen from the above test results, it was determined that combining the first projection step and the second projection step is an appropriate method for roughening the inner surface 25 of the slinger 20A.

[0097] Next, examples of applying other shapes of slinger 20A (slinger body 20) to the manufacturing method of the sealing device according to this embodiment will be described with reference to Figures 5 and 6. In the figures, D1 is the projection direction of the projection material 41 in the first projection step, and D2 is the projection direction of the projection material 41 in the second projection step.

[0098] The slinger body 20 shown in Figure 5(a) has a shape in which the first inner corner portion 25d is not curved, but slopes upward in a planar manner from the disc portion 21 toward the first cylindrical portion 22. The second cylindrical portion 23 has a smaller degree of protrusion than the first cylindrical portion 22.

[0099] The slinger body 20 shown in Figure 5(b) has a first inner corner portion 25d that is curved at a larger radius than the first inner corner portion 25d of the slinger 20A shown in Figure 2. The second cylindrical portion 23 has a smaller degree of protrusion than the first cylindrical portion 22.

[0100] The slinger 20A shown in Figure 5(c) has a first inner corner portion 25d that is not curved, but rather slopes upward from the disc portion 21 toward the first cylindrical portion 22. The second cylindrical portion 23 has a smaller protrusion than the first cylindrical portion 22 and is inclined to tilt toward the opposite side from the recessed space 24.

[0101] With these slinger bodies 20 as well, a wide area of ​​the surface facing the recessed space 24 of the slinger body 20 can be roughened by combining the first projection step and the second projection step. In particular, in the case of Figure 5(c), the second cylindrical portion 23 has an inclined shape and the recessed space 24 widens radially upward, making it easier to project the projection material 41 in the first projection step.

[0102] Furthermore, in the slinger body 20 shown in Figure 6(a), the degree of protrusion of the second cylindrical portion 23 is greater than that of the first cylindrical portion 22. With this shape, the projection area of ​​the projection material 41 in the first projection step becomes smaller, but the second projection step can compensate for the widening of the roughening area and the uniformity of the roughening.

[0103] Furthermore, since the slinger body 20 in Figure 6(b) is L-shaped and does not have a second cylindrical portion 23, the first surface 25a, the second surface 25b, and the first inner corner portion 25d can be easily roughened by the first and second projection steps. Because there is no second cylindrical portion 23, the projection angle of the first projection step can be as low as 10 degrees.

[0104] Of the five examples in Figures 5 and 6, Figures 5(a) to (c) and 6(a) have a U-shaped slinger body 20, and therefore can be applied to the sealing device 10 in Figure 2, which uses a U-shaped slinger body 20.

[0105] The above describes the sealing device 10 on the vehicle body side, but the above configuration of the sealing device 10 can also be applied to the other sealing device 11 on the wheel side. Furthermore, it goes without saying that the above manufacturing method (surface roughening method) can also be applied to both the vehicle body side and the wheel side sealing devices 10 and 11.

[0106] In the embodiments described above, sealing devices 10 and 11 were illustrated in which the fixed member 2 is an outer ring member and the rotating member 3 is an inner ring member. However, the present invention can also be applied to sealing devices in which the fixed member 2 is an inner ring member and the rotating member 3 is an outer ring member.

[0107] The sealing device 10 described above is merely an example, and other designs are also acceptable. Furthermore, it goes without saying that the overall shape of the sealing device 10 can be modified as appropriate from a design perspective.

[0108] Furthermore, the method of manufacturing the sealing device according to this embodiment is merely an example, and other methods are also acceptable. Various structures of the projection device 40 can also be applied. [Explanation of symbols]

[0109] 1. Bearing device 2. Fixing member (outer ring member) 3. Rotating member (inner ring member) 3a Inner ring 3b Hub wheel 6. Sealed space 10 Sealing device 11. Sealing devices (other sealing devices) 20A Slinger 20 Slinger main unit 21 Disc section 22 First cylindrical section 23 Second cylindrical section 24 Recessed space 25 Inner self 25a 1st page 25b 2nd side 25c 3rd page 25d First inner corner 25e Second corner 30A Core material section 30 Core body 31 Core disc section 32 Core cylindrical section 35 Seal lip section 35a Seal body 35b First lip piece 35c Second lip piece 40 Projection device 41 Projection material A (Inner part of the first surface) B (The central part of the first page) C (Outer part of the first surface) Area D (where the second lip piece on the second surface is in contact with or close to)

Claims

1. An annular sealing device comprising a core portion fitted and fixed to one of two members that rotate concentrically relative to each other, and a slinger fitted and fixed to the other member, configured to seal the space between the two members, The core material portion includes a seal lip portion made of an elastic material that rotates relative to the slinger while in contact with it. The slinger comprises a first cylindrical portion for fitting, a disc portion, and a second cylindrical portion, and has a recessed space with the first cylindrical portion, the disc portion, and the second cylindrical portion forming an outer frame. A sealing device characterized in that at least two continuous surfaces, a first surface corresponding to the disc portion and a second surface adjacent to the first surface, which face the recessed space, are roughened.

2. In claim 1, A sealing device characterized in that substantially the entire surface of the two continuous surfaces is continuously roughened, including the inner corners of both surfaces.

3. In claim 1, The second surface is the surface corresponding to the first cylindrical portion. The seal lip portion comprises a first lip piece corresponding to the first surface and a second lip piece corresponding to the second surface. A sealing device characterized in that, during the relative rotational movement, at least one of the first lip piece and the second lip piece elastically contacts the target surface.

4. In claim 1, A sealing device characterized in that the arithmetic mean roughness of the first surface and the second surface, respectively, is 0.4 or more and 0.9 or less.

5. In claim 1, The first surface consists of three regions: an inner portion, a central portion, and an outer portion, which are virtually divided along the radial direction into approximately equal radial lengths. A sealing device characterized in that the ratio of the arithmetic mean roughness of the outer portion to the arithmetic mean roughness of the central portion is greater than the ratio of the arithmetic mean roughness of the inner portion to the arithmetic mean roughness of the central portion, and the difference is 0.25 or less.

6. In claim 1, The first surface consists of three regions: an inner portion, a central portion, and an outer portion, which are virtually divided along the radial direction into approximately equal radial lengths. A sealing device characterized in that the ratio of the arithmetic mean roughness of the second surface to the arithmetic mean roughness of the central portion is greater than the ratio of the arithmetic mean roughness of the inner portion to the arithmetic mean roughness of the central portion.

7. In claim 1, A sealing device characterized in that the inner corner between the first surface and the third surface corresponding to the second cylindrical portion is roughened.

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