JP7702263B2 - Device equipped with a sealing mechanism - Google Patents

Description

The present invention relates to a device equipped with a sealing mechanism.

Devices equipped with a sealing mechanism that seals between a shaft member and a case are known. For example, Patent Document 1 describes a device equipped with a seal that includes a sealing member and a slinger surrounded by the sealing member. This sealing mechanism includes a slinger provided on the outer peripheral surface of the shaft member, and a sealing member provided between the case and the slinger. The slinger has a flange portion that is located from the cylindrical portion to the inside of the shaft member.

JP 2019-082198 A

The present inventors have come to the following realization regarding an apparatus equipped with a sealing mechanism.
In the seal mechanism, uneven wear of the oil seal lip is considered to be a factor in the deterioration of the sealing function that suppresses leakage of the lubricant. In order to suppress uneven wear of the lip, it is important to improve the press-fitting accuracy and reduce the eccentricity of the slinger after assembly. However, in the seal mechanism described in Patent Document 1, the inside of the slinger is made of an elastic material and there is a large gap between the metal part of the slinger and the shaft member, and in this structure, the seal is assembled in an inclined state, which increases the eccentricity of the slinger after assembly.

The present invention was made in consideration of these circumstances, and one of its objectives is to provide a device equipped with a sealing mechanism that can suppress eccentricity of the slinger after assembly.

In order to solve the above problems, one aspect of the present invention is a device comprising a shaft member, a case that houses at least a portion of the shaft member, and a sealing mechanism that seals between the shaft member and the case, and the sealing mechanism comprises a slinger provided on the outer peripheral surface of the shaft member, and a sealing member provided between the case and the slinger. The slinger comprises a cylindrical portion and a flange portion that protrudes from the cylindrical portion toward the shaft member. An elastic member having a smaller elastic modulus than the flange portion is provided between the cylindrical portion and the shaft member, and the flange portion abuts against the shaft member in the radial direction.

The present invention provides a device equipped with a sealing mechanism that can suppress eccentricity of the slinger after assembly.

1 is a side cross-sectional view that shows a schematic diagram of an apparatus equipped with a sealing mechanism according to a first embodiment. FIG. 2 is an enlarged view of the sealing mechanism of FIG. 1 . FIG. 11 is an enlarged view showing a sealing mechanism according to a second embodiment.

The present invention will be described below based on a preferred embodiment with reference to the drawings. In the embodiments and modified examples, identical or equivalent components and parts are given the same reference numerals, and duplicated explanations will be omitted as appropriate. Furthermore, the dimensions of the parts in each drawing are shown enlarged or reduced as appropriate to facilitate understanding. Furthermore, some parts that are not important for explaining the embodiment are omitted in each drawing.

In addition, terms including ordinal numbers such as first and second are used to describe various components, but these terms are used only for the purpose of distinguishing one component from another and do not limit the components.

[First embodiment]
The configuration of the seal mechanism 4 according to the first embodiment will be described below with reference to the drawings. Fig. 1 is a side cross-sectional view showing an apparatus 100 to which the seal mechanism 4 according to the first embodiment of the present invention is applied. The apparatus 100 includes a shaft member 2, a case 3, a seal mechanism 4, and a bearing 8. The case 3 accommodates at least a portion of the shaft member 2. The case 3 may be formed approximately coaxially with the shaft member 2.

The sealing mechanism 4 seals between the shaft member 2 and the case 3. The sealing mechanism 4 includes a slinger 5 provided on the outer circumferential surface 22 of the shaft member 2, and a sealing member 6 provided between the case 3 and the slinger 5. As an example, the device 100 may be a reducer or an eccentric oscillating reducer. In this case, the shaft member 2 corresponds to the carrier, the case 3 corresponds to a cylindrical casing that covers the outer periphery of the carrier, and the bearing 8 corresponds to the main bearing.

Hereinafter, the direction along the central axis La of the shaft member 2 of the device 100 will be referred to as the "axial direction," and the circumferential direction and radial direction of the circle centered on the central axis La will be referred to as the "circumferential direction" and "radial direction," respectively. The central axis La in this example coincides with the rotational axis of the shaft member 2. A bearing 8 is provided between the case 3 and the shaft member 2. The shaft member 2 is disposed within the case 3 and supported so as to be rotatable relative to the case 3.

In this embodiment, at least one of the shaft member 2 and the case 3 rotates around the rotation axis La. For example, the case 3 may be fixed and the shaft member 2 may rotate, or the shaft member 2 may be fixed and the case 3 may rotate.

In this embodiment, the case 3 forms an internal space that houses a part or all of the shaft member 2. The internal space of the case 3 may house various components used as part of the device 100 together with the shaft member 2. As an example, the internal space of the case 3 may house gear parts that can be connected to the shaft member 2, but is not limited to this.

The bearing 8 is disposed on one side and the other side of the axial direction of the case 3 and the shaft member 2. The bearing 8 has a plurality of rolling elements 82 arranged at intervals in the circumferential direction. In the example of FIG. 1, the inner ring side rolling surface 83 of the bearing 8 is formed on the outer peripheral surface of the shaft member 2, and the outer ring side rolling surface 842 is formed on an outer ring 84 fitted into the inner peripheral surface of the case 3. In other words, the outer ring 84 of the bearing 8 is formed separately from the case 3. A lubricant (not shown) is held in the bearing 8.

In the space between the case 3 and the shaft member 2, the area in which the bearings 8 that hold the lubricant are arranged and sealed by the sealing mechanism 4 is called the "lubricant retention space J." In addition, in the axial direction, the direction away from the lubricant retention space J is called the "outside," and the opposite direction is called the "inside." The inner and outer ends of the member are called the "inner end" and "outer end." In addition, in the ventilation path from the lubricant retention space J to the external space of the device 100, the side approaching the lubricant retention space J is called the "inner side," and the opposite side is called the "outer side."

Figure 2 is an enlarged view of the seal mechanism 4 of this embodiment. This figure shows a cross section cut along the radial direction. The seal mechanism 4 includes a seal member 6 that seals the gap formed between the shaft member 2 and the case 3, and a slinger 5. In particular, the seal mechanism 4 seals the gap between the case 3 and the shaft member 2 by the seal member 6 coming into contact with the slinger 5. The slinger 5 may be bonded to the shaft member 2.

The slinger 5 is located between the shaft member 2 and the case 3. In this embodiment, the slinger 5 is inserted into the shaft member 2. The slinger 5 is an annular member located radially outward from the shaft member 2. The slinger 5 will be described later.

The seal member 6 has a lip portion 62 and a lip support portion 63. The lip portion 62 contacts the slinger 5 to form a seal between the case 3 and the slinger 5. The lip support portion 63 is an annular portion that fits into the inner peripheral surface 32 of the case 3 and supports the lip portion 62 on the inner peripheral side of the lip support portion 63. The lip portion 62 extends radially from the lip support portion 63 toward the outer peripheral surface 512 of the slinger 5. In this example, the seal member 6 is removably attached to the case 3 on the axial outside of the slinger 5.

The lip portion 62 may include multiple lip portions that are elastically deformable. In this example, the lip portion 62 includes a main lip 623 for contacting the outer peripheral surface 512 of the slinger 5 and a dust lip 624. The main lip 623 functions as a main lip that can suppress leakage of the lubricant in the lubricant retaining space J to the outside. The dust lip 624 functions as a dust lip that suppresses leakage of the lubricant in the lubricant retaining space J to the outside and suppresses the intrusion of foreign matter into the lubricant retaining space J from the outside.

The lip portion 62 has a spring ring 625. The spring ring 625 is an annular member provided on the outer periphery of the main lip 623. The spring ring 625 surrounds the main lip 623 and applies a force to the main lip 623 toward the center of the shaft member 2. With this configuration, the main lip 623 adheres closely to the outer periphery 512 of the cylindrical portion 51, creating a sealing function between the main lip 623 and the cylindrical portion 51. The dust lip 624 abuts against the outer periphery 512 of the cylindrical portion 51 of the slinger 5.

The lip support part 63 has an elastic part 632 and a rigid part 631. The rigid part 631 functions as a core material that maintains the shape of the elastic part 632 within a certain range. The rigid part 631 can be made of a metal material such as an iron-based metal, a non-metal material such as a hard plastic, or a composite material of these. The rigid part 631 is an annular member with an L-shaped cross section cut along the radial direction. The rigid part 631 has a hollow disc-shaped disc part and a hollow cylindrical part that extends axially inward from the outer periphery of the disc part. The elastic part 632 covers the entire rigid part 631. The elastic part 632 is made of a soft resin material such as rubber. The lip part 62 is integrally formed with the elastic part 632 of the lip support part 63.

(Slinger)
The slinger 5 includes a tubular portion 51 and a flange portion 52 located radially inward of the shaft member 2 from the tubular portion 51. The tubular portion 51 in this example has a cylindrical shape having a substantially coaxial outer circumferential surface 512 and an inner circumferential surface 513. The tubular portion 51 may have any shape.

Between the cylindrical portion 51 and the shaft member 2, an elastic member 56 having a smaller elastic coefficient than the flange portion 52 is provided. In this example, the elastic member 56 has a cylindrical shape having an outer peripheral surface 562 and an inner peripheral surface 563 that are substantially coaxial. The cylindrical portion 51 may have any shape. In a state before being inserted into the slinger 5 (hereinafter referred to as the "uninserted state"), the outer peripheral surface 562 may have the same diameter as or slightly larger than the inner peripheral surface 513 of the cylindrical portion 51. In a state inserted into the slinger 5 (hereinafter referred to as the "inserted state"), the outer peripheral surface 562 may be in close contact with the inner peripheral surface 513. The elastic member 56 may be crushed in the radial direction in the inserted state. The elastic member 56 may be, for example, a sticky adhesive. In this case, the adhesive may be applied to a portion of the area in order to reduce the seepage of the adhesive to areas other than the flange portion 52.

The flange portion 52 abuts against the shaft member 2 in the radial direction. The flange portion 52 and the shaft member 2 may be a tight fit with an interference, a clearance fit with no interference and a small gap, or an intermediate fit. In the case of a clearance fit, the clearance can be set according to the allowable eccentricity of the slinger 5 after assembly. The flange portion 52 has a protruding shape that protrudes radially inward from the inner peripheral surface 513 of the cylindrical portion 51. The radial thickness of the flange portion 52 may be smaller than the radial thickness of the elastic member 56 in the uninserted state. In this case, the elastic member 56 elastically deforms in the radial direction in the inserted state and assumes a shape that conforms to the shape of the outer peripheral surface 22 of the shaft member 2.

When the shaft member 2 is inserted into the slinger 5, the side of the slinger 5 that first comes into contact with the shaft member 2 is called the "insertion side" and the opposite side is called the "anti-insertion side". In other words, the "insertion side" can be said to be the side inside the device (the side closer to the space in which the lubricant is sealed), and the "anti-insertion side" can be said to be the side outside the device. In the example of FIG. 2, the flange portion 52 includes a first flange portion 53 that is disposed on the insertion side of the elastic member 56. In this case, the high-precision flange portion 52 comes into contact with the shaft member 2 before the elastic member 56, and the elastic member 56 comes into contact with the shaft member 2 with both being roughly aligned, so that the elastic member 56 comes into contact roughly evenly in the circumferential direction, and uneven deformation in the circumferential direction can be avoided.

Flange portion 52 also includes a second flange portion 54 that is disposed on the anti-insertion side of elastic member 56. Flange portion 52 may be disposed away from the end of tubular portion 51, but in this example, first flange portion 53 and second flange portion 54 are disposed at the end of tubular portion 51. In other words, first flange portion 53 and second flange portion 54 are disposed at both axial ends of tubular portion 51. In this case, the flange portions abut against shaft member 2 on both axial sides of elastic member 56, so that elastic member 56 contacts shaft member 2 approximately uniformly in the axial direction, and uneven deformation in the axial direction can be avoided.

When inserting the shaft member 2 into the flange portion 52, it is desirable that the two be inserted in a roughly aligned state. For this reason, the flange portion 52 is provided with a guide taper portion 522 that serves as a guide during insertion. In this case, the slinger 5 is aligned with the shaft member 2, so that the eccentricity of the slinger after assembly can be reduced. From the viewpoint of ensuring the alignment function, chamfering (for example, about 0.1 mm) to remove burrs and other imperfections is insufficient. Studies have suggested that the axial size of the taper portion 522 is preferably 0.5 mm or more, and more preferably 0.7 mm or more. In this embodiment, the axial size of the taper portion 522 is set to 0.7 mm to 1.5 mm.

Furthermore, studies have suggested that the inclination of the tapered portion 522 with respect to the central axis La is preferably 45° or less, and more preferably 35° or less. In this embodiment, the inclination of the tapered portion 522 with respect to the central axis La is set to 25° to 35°. In other words, it is preferable that the axial size of the tapered portion 522 is longer than the radial size of the tapered portion 522.

In this embodiment, the tapered portion 522 is provided at the corners on the inner circumference side of both ends of the first flange portion 53 and the second flange portion 54. In this example, the axial size of the tapered portion 522 is larger than the axial size of the other chamfered portions 523 on the inner circumference side of the first flange portion 53 and the second flange portion 54.

For example, the slinger in Patent Document 1 is asymmetric in the axial direction and can only be inserted in one direction, so there is a risk that defective products will be released onto the market due to incorrect insertion. In contrast, the slinger 5 of this embodiment has tapered sections 522 at the outward corners of the first flange section 53 and the second flange section 54, so that the shaft member 2 can be inserted from both the first flange section 53 and the second flange section 54. For this reason, there is almost no risk of defective products being released onto the market due to incorrect insertion. In addition, the insertion work can be performed without worrying about the orientation of the slinger 5, reducing the amount of work required.

It is desirable that the axial position of the slinger 5 relative to the shaft member 2 is constant. Therefore, in this embodiment, the slinger 5 is restricted from moving in the axial direction toward the inside relative to the shaft member 2 by the flange portion 52. In the example of FIG. 2, the shaft member 2 has an abutment wall portion 23 extending radially outward from the outer circumferential surface 22, and the first flange portion 53 of the slinger 5 abuts against the abutment wall portion 23. In this case, the positional accuracy is higher than that of a configuration in which movement is restricted by the elastic member 56, and the radial dimension of the abutment wall portion 23 can be smaller than that of a configuration in which movement is restricted by the cylindrical portion 51. The abutment wall portion 23 may be a wall portion of a radial convex portion or a wall portion of a step portion. The radial outer position of the abutment wall portion 23 may be radially inward from the outer periphery of the flange portion 52. In the example of FIG. 2, the radial outer position of the abutment wall portion 23 is radially outward from the outer periphery of the flange portion 52 and radially inward from the outer periphery chamfer on the insertion side of the cylindrical portion 51.

The outer peripheral surface 22 of the shaft member 2 will be described with reference to Figs. 1 and 2. As described above, this embodiment has a bearing 8 arranged between the shaft member 2 and the case 3. The outer peripheral surface 22 of the shaft member 2 has an inner race rolling surface 83 of the rolling body 82 of the bearing 8, a slinger arrangement surface 24 on which the slinger 5 is arranged, and a connection surface 25 provided between the inner race rolling surface 83 and the slinger arrangement surface 24. In the example of Fig. 2, the outer diameter of the slinger arrangement surface 24 is smaller than the outer diameter of the connection surface 25. In this case, the slinger 5 is prevented from passing over the slinger arrangement surface 24 and entering the connection surface 25. Also, in the example of Fig. 2, the outer diameter of the outer peripheral surface 512 of the cylindrical portion 51 of the slinger 5 is larger than the outer diameter of the connection surface 25. In this case, the gap between the inner peripheral surface 32 of the case 3 and the outer peripheral surface 512 of the cylindrical portion 51 of the slinger 5 can be narrowed to improve sealing performance.

The features of the device 100 of the present embodiment configured as described above will be described. The device 100 includes a shaft member 2, a case 3 that houses at least a portion of the shaft member 2, and a seal mechanism 4 that seals between the shaft member 2 and the case 3. The seal mechanism 4 includes a slinger 5 provided on the outer peripheral surface 22 of the shaft member 2 and a seal member 6 provided between the case 3 and the slinger 5. The slinger 5 includes a cylindrical portion 51 and a flange portion 52 that protrudes from the cylindrical portion 51 toward the shaft member 2. An elastic member 56 having a smaller elastic modulus than the flange portion 52 is provided between the cylindrical portion 51 and the shaft member 2, and the flange portion 52 abuts against the shaft member 2 in the radial direction.

With this configuration, the flange portion 52 abuts against the shaft member 2 in the radial direction, which reduces the inclination of the slinger 5 relative to the shaft member 2 and reduces the eccentricity of the slinger 5 after assembly compared to a configuration in which they do not abut.

[Second embodiment]
Next, a second embodiment of the present invention will be described. In the drawings and description of the second embodiment, the same or equivalent components and members as those of the first embodiment are denoted by the same reference numerals. Explanations that overlap with the first embodiment will be omitted as appropriate, and the description will focus on the configurations that differ from the first embodiment.

The second embodiment of the present invention is also a device equipped with a sealing mechanism. FIG. 3 is an enlarged view of the sealing mechanism according to the second embodiment, and corresponds to FIG. 2. The sealing mechanism 4 according to this embodiment differs from the example of FIG. 2 in that the shape of the slinger 5 is different, and in particular, the flange portion 52 includes a third flange portion 55 that overlaps the lip portion 62 of the sealing member 6 when viewed from the radial direction. In this example, the third flange portion 55 is provided between the first flange portion 53 and the second flange portion 54 in the axial direction, at a position that overlaps the lip portion 62 of the sealing member 6 when viewed from the radial direction. In particular, a part or all of the third flange portion 55 overlaps the main lip 623 when viewed from the radial direction.

The characteristics of the third flange portion 55 are similar to the characteristics of the first flange portion 53 and the second flange portion 54. In this example, the flange portion 52 includes three flange portions, but the number of flange portions is not limited to three, and may be two or less, or four or more.

This embodiment has the same effect as the first embodiment. In addition, because the flange portion 52 overlaps the lip portion 62 of the seal member 6 when viewed from the radial direction, the deflection caused by the contact pressure of the lip portion 62 can be reduced even if the radial thickness of the cylindrical portion 51 is made thin. Furthermore, under conditions where the radial thickness of the cylindrical portion 51 is constant, the contact pressure of the lip portion 62 can be increased to improve the sealing function.

Above, examples of the embodiments of the present invention have been described in detail. All of the above-mentioned embodiments merely show specific examples of how to put the present invention into practice. The contents of the embodiments do not limit the technical scope of the present invention, and many design changes such as changing, adding, or deleting components are possible within the scope of the idea of the invention defined in the claims. In the above-mentioned embodiments, the contents for which such design changes are possible are explained with notations such as "in the embodiment" and "in the embodiment", but this does not mean that design changes are not permitted for contents without such notations. Furthermore, hatching in the drawings does not limit the material of the object to which the hatching is applied.

[Modification]
The following describes the modified examples. In the drawings and description of the modified examples, the same or equivalent components and members as those in the embodiment are denoted by the same reference numerals. Descriptions that overlap with the embodiment will be omitted as appropriate, and the description will focus on configurations that differ from the embodiment.

In the description of the embodiment, an example was given in which the device 100 is a reducer, but the present invention is not limited to this. The device 100 may be any device having a shaft member, a case, and a sealing mechanism, and may be, for example, a motor, various types of transmissions, or a coupling mechanism. In addition, the shaft member 2 is not limited to a specific shape, and may be, for example, a columnar member, a cylindrical member, or a member with another shape.

In the description of the embodiment, an example was given in which the sealing mechanism 4 is a sealing mechanism for a reducer, but the present invention is not limited to this. The sealing mechanism 4 is not limited to a specific device, but can be applied to any device equipped with a rotating member.

In the description of the embodiment, an example has been shown in which the sealing mechanism 4 is provided on one side of the device 100 in the axial direction, but the sealing mechanism 4 may be provided on both sides of the device 100 in the axial direction.

In the description of the embodiment, an example was shown in which the inner ring side rolling surface 83 is formed on the outer circumferential surface of the shaft member 2, but an inner ring separate from the shaft member 2 may also be provided, and the inner ring side rolling surface may be formed on the inner ring.

Each of the above-mentioned modified examples provides the same effects and advantages as the embodiment.

Any combination of the above-described embodiments and modifications is also useful as an embodiment of the present invention. The new embodiment resulting from the combination has the combined effects of each of the combined embodiments and modifications.

2 Shaft member, 3 Case, 4 Sealing mechanism, 5 Slinger, 6 Sealing member, 8 Bearing, 51 Cylindrical portion, 52 Flange portion, 53 First flange portion, 54 Second flange portion, 55 Third flange portion, 56 Elastic member, 62 Lip portion, 522 Guide taper portion, 100 Device.

Claims (8)

A shaft member;
a case that accommodates at least a portion of the shaft member;
a seal mechanism for sealing between the shaft member and the case,
The sealing mechanism includes a slinger provided on an outer circumferential surface of the shaft member, and a sealing member provided between the case and the slinger,
The slinger includes a cylindrical portion and a flange portion protruding from the cylindrical portion toward the shaft member,
The seal member includes a lip portion that is in radial contact with the cylindrical portion of the slinger, and a lip support portion that supports the lip portion.
an elastic member having an elastic modulus smaller than that of the flange portion is provided between the cylindrical portion and the shaft member;
The flange portion abuts against the shaft member in a radial direction,
The device is characterized in that the shaft member has a wall portion located radially outward from the arrangement surface of the shaft member on which the slinger is arranged, and which restricts axial movement of the slinger via the flange portion . The device according to claim 1, characterized in that the flange portion is positioned on the insertion side of the elastic member. The device according to claim 1 or 2, characterized in that the flange portion is disposed at both axial ends of the cylindrical portion. The device according to any one of claims 1 to 3, characterized in that the slinger is restricted from moving axially inward relative to the shaft member by the flange portion. The device according to any one of claims 1 to 4, characterized in that the flange portion is provided with a guide tapered portion that serves as a guide when inserted into the shaft member. The device according to any one of claims 1 to 5, characterized in that, when viewed from the radial direction, the flange portion overlaps the lip portion of the seal member. a bearing disposed between the shaft member and the case;
The outer peripheral surface of the shaft member has an inner ring side rolling surface of the rolling body of the bearing, a slinger arrangement surface on which the slinger is arranged, and a connection surface provided between the inner ring side rolling surface and the slinger arrangement surface,
7. The apparatus of claim 1, wherein an outer diameter of the slinger mounting surface is smaller than an outer diameter of the connecting surface. The device according to claim 7, wherein the outer diameter of the tubular portion of the slinger is greater than the outer diameter of the connection surface.

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