JP7478411B2 - Mold - Google Patents

Description

The present invention relates to a mold used to mold a sealing member.

2. Description of the Related Art Conventionally, a sealing member is known that is interposed between an inner peripheral surface of an outer peripheral member and an outer peripheral surface of an inner peripheral member that face each other in a radial direction.
For example, the following Patent Document 1 discloses a seal member having a protrusion on the seal lip that creates an oil passage that communicates between the bearing internal space and the external space so that an oil film is formed between the seal sliding surface and the seal lip to reduce torque. When molding such a seal member, it is considered to mold it using a mold that includes a female mold that is provided with an uneven shape corresponding to the protrusion and the oil passage, and a male mold that is provided with a burr groove whose groove opening periphery is unevenly shaped according to the uneven shape of the female mold. In this case, the processing cost of the mold increases, and it is necessary to precisely align the uneven shapes of the female mold and the male mold in the circumferential direction.
The following Patent Document 2 discloses a mold including a female mold having an uneven shape that forms multiple protrusions on a seal lip portion, and a male mold having an inner diameter side burr groove whose radially maximum portion is circular on the inner diameter side peripheral edge of a cavity. This mold is configured such that the diameter of the radially maximum portion of the inner diameter side burr groove is equal to or smaller than the diameter of a circle that is tangent to the tips of the multiple protrusions on the seal lip portion.

Patent No. 6523994 JP 2018-119624 A

However, the mold described in Patent Document 2 above has a tendency for thin burrs to remain between adjacent protrusions at the tip of the seal lip, and further improvement is desired.

The present invention was made in consideration of the above-mentioned circumstances, and aims to provide a mold that can reduce the processing costs of the mold itself while reducing the amount of burrs remaining between the protrusions of the lip portion of the sealing member.

In order to achieve the above object, a mold according to the present invention is a mold used for molding a sealing member, in which a sliding contact portion of an annular lip portion that is in sliding contact with a first surface of an inner peripheral surface of an outer peripheral side member and an outer peripheral surface of an inner peripheral side member that are opposed in the radial direction has a plurality of protrusions provided around the entire circumference at intervals in the circumferential direction so as to define a communication groove that communicates between a sealed space and an external space, and the first mold portion has a concave-convex peripheral wall portion that defines an annular cavity, the concave-convex peripheral wall portion having concave-convex projections and convexities corresponding to the protrusions of the sliding contact portion of the lip portion and the communication grooves that are alternately provided in the circumferential direction; and a second mold adjacent to one radial side of the concave-convex peripheral wall portion of the first mold and having an annular groove extending in the circumferential direction for receiving molding material overflowing from the cavity, wherein a groove opening peripheral portion on the other radial side of the annular groove has a part that is shaped according to the concave-convex peripheral wall portion when viewed in the axial direction and another part that is an arc-shaped portion, and the arc portion of the annular groove is provided so as to be located on the other radial side of an imaginary circle connecting the bottoms of the recesses on the dividing surface side peripheral portion of the concave-convex peripheral wall portion.
In order to achieve the above object, the present invention provides a mold for use in molding a sealing member, in which a sliding contact portion of an annular lip portion that is in sliding contact with a first surface of an inner peripheral surface of an outer peripheral side member and an outer peripheral surface of an inner peripheral side member that are opposed in the radial direction has a plurality of projections provided around the entire circumference at intervals in the circumferential direction so as to define a communication groove that communicates between a sealed space and an external space, the mold comprising: a first mold having an uneven peripheral wall portion that defines an annular cavity, and a second mold adjacent to one radial side of the uneven peripheral wall portion of the first mold and configured to extend from the cavity to the outer space; and a second mold in which an annular groove is provided extending in the circumferential direction to receive overflowing molding material, wherein a groove opening peripheral portion on the other radial side of the annular groove has a part shaped to correspond to the uneven peripheral wall portion when viewed in the axial direction, and another portion is an arc-shaped arc portion, the arc portion of the annular groove is provided to coincide with an imaginary circle connecting the tips of the convex portions of the dividing surface side peripheral portion of the uneven peripheral wall portion or to be located on the other radial side of the imaginary circle, and the portion of the annular groove shaped to correspond to the uneven peripheral wall portion is shaped to correspond to the concave portions of the dividing surface side peripheral portion of the uneven peripheral wall portion.
In order to achieve the above object, the present invention provides a mold for molding a sealing member, in which a sliding contact portion of an annular lip portion that is in sliding contact with a first surface of an inner peripheral surface of an outer peripheral side member and an outer peripheral surface of an inner peripheral side member that are opposed in the radial direction has a plurality of protrusions provided around the entire circumference at intervals in the circumferential direction so as to define a communication groove that communicates a sealed space with an external space, the mold comprising: a first mold having a concave-convex peripheral wall portion that defines an annular cavity, and a cavity adjacent to one radial side of the concave-convex peripheral wall portion of the first mold. and a second mold in which an annular groove is provided extending in the circumferential direction to receive molding material overflowing from a bit, wherein a groove opening peripheral portion on the other radial side of the annular groove has a part shaped to correspond to the uneven peripheral wall portion when viewed in the axial direction, and another portion is an arc-shaped arc portion, the arc portion of the annular groove is provided to be located on one radial side of an imaginary circle connecting the tips of the convex portions of the dividing surface side peripheral portion of the uneven peripheral wall portion, and the portion of the annular groove shaped to correspond to the concave and convex peripheral wall portion is shaped to correspond to the convex portions of the dividing surface side peripheral portion of the uneven peripheral wall portion.

The mold according to the present invention has the above-mentioned configuration, which makes it possible to reduce the processing cost of the mold itself while reducing the amount of burrs remaining between the protrusions of the lip portion of the sealing member.

1A and 1B are schematic views of an example of a bearing device incorporating an example of a sealing member molded using an example of a mold according to one embodiment of the present invention, where 1A is a partially cutaway schematic vertical cross-sectional view, and 1B is a partially cutaway schematic vertical cross-sectional view with a portion corresponding to portion Y1 in 1A omitted. 4A and 4B are schematic views showing an example of the same mold, in which FIG. 4A is a partially cutaway schematic vertical sectional view corresponding to the X1-X1 line arrow view in FIG. 3 and FIG. 4A, and FIG. 4B is a partially cutaway schematic vertical sectional view corresponding to the Y2 portion in FIG. FIG. 2 is a schematic plan view, partially cut away, illustrating an example of a first mold included in the mold. 1A is a schematic bottom view, partially cut away, showing an example of a second mold provided in the mold, and FIG. 1B is a schematic bottom view, partially cut away, showing a portion corresponding to the Z1 portion in FIG. 6A and 6B are schematic views showing an example of a mold according to another embodiment of the present invention, in which FIG. 6A is a partially cutaway schematic vertical cross-sectional view corresponding to the X2-X2 line arrow view in FIG. 6A, and FIG. 6B is a partially cutaway schematic vertical cross-sectional view corresponding to the Y3 portion in FIG. 1A is a schematic bottom view, partially cut away, showing an example of a second mold provided in the mold, and FIG. 1B is a schematic bottom view, partially cut away, showing a portion corresponding to the Z2 portion in FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In some drawings, some of the detailed reference numerals used in other drawings are omitted.
In addition, in each of the following embodiments, the radial, circumferential and axial directions of the mold will be described as being the same as the radial, circumferential and axial directions of a bearing device into which a sealing member molded using the mold of each embodiment is incorporated.

1 to 4 are diagrams that show an example of a mold according to a first embodiment, an example of a sealing member molded using the mold, and an example of a bearing device in which the sealing member is incorporated.
As shown in Fig. 1, a mold 1 (see Fig. 2) according to this embodiment is used to mold a sealing member 3 in which a plurality of protrusions 36 are provided around the entire circumference at intervals in the circumferential direction on a sliding contact portion 35 of an annular lip portion 34 that is in sliding contact with a first surface of an inner peripheral surface 4b of an outer peripheral side member 4 and an outer peripheral surface 5b of an inner peripheral side member 5 that are opposed in the radial direction so as to define a communication groove 37 that communicates a sealed space 8 with an external space. Fig. 1(a) shows an example in which this sealing member 3 is incorporated into a bearing device 2 that includes an outer peripheral side member 4 that constitutes an outer ring and an inner peripheral side member 5 that constitutes an inner ring that rotate coaxially relative to each other.

This bearing device 2 is configured, for example, such that an outer peripheral member 4 is fitted into a bearing such as a housing, a shaft 9 is inserted into an inner peripheral member 5, and the inner peripheral member 5 rotates together with the shaft 9 relative to the outer peripheral member 4.
The bearing device 2 is a rolling bearing device having rolling elements (balls in the illustrated example) 7 interposed between an outer peripheral member 4 and an inner peripheral member 5. The bearing device 2 may support a shaft 9 of a transmission of various vehicles such as an automobile, or may support a shaft 9 provided as any of various other rotating parts.
Between the outer peripheral member 4 and the inner peripheral member 5, an annular sealed space 8 is formed around the entire circumference.

In the sealed space 8, the raceway 4a of the outer peripheral member 4 and the raceway 5a of the inner peripheral member 5 are interposed so as to be able to roll, with the single row of rolling elements 7 held by a retainer (cage) 6. Lubricating oil is supplied to the sealed space 8 by filling with appropriate grease, splashing oil, spraying oil from a nozzle, an oil bath, or the like. The bearing device 2 may be configured with the rolling elements 7 arranged in double rows between the outer peripheral member 4 and the inner peripheral member 5. The bearing device 2 is not limited to a deep groove ball bearing in which groove-shaped raceways 4a, 5a are provided on the outer peripheral member 4 and the inner peripheral member 5 as shown in the figure, but may also be an angular ball bearing. The bearing device 2 is not limited to a ball bearing in which the rolling elements 7 are balls, but may also be a roller bearing in which the rolling elements 7 are cylindrical rollers, tapered rollers, or the like, and may also be a bearing device 2 in which one of the outer peripheral member 4 and the inner peripheral member 5 has a flange-shaped, hub-shaped, or the like fixed portion.
Further, the sealing members 3, 3 are mounted between the outer peripheral member 4 and the inner peripheral member 5 at both ends in the axial direction of the sealed space 8. Both axial ends of the sealed space 8 are sealed by the sealing members 3, 3 on both axial sides, thereby preventing the intrusion of foreign matter into the sealed space 8 and the leakage of grease filled in the sealed space 8 to the outside. Since the sealing members 3, 3 on both axial sides have the same configuration, the following description will be given taking one of the sealing members 3 as an example. Furthermore, the bearing device 2 into which the sealing member 3 is incorporated is not limited to the configuration described above, and may have various other configurations.

In the illustrated example, the sealing member 3 is configured such that a sliding portion 35 of the lip portion 34 is in sliding contact with an outer peripheral surface 5b constituting a first surface of the inner peripheral side member 5 which is a rotating member. In other words, the sealing member 3 is configured to have the lip portion 34 on the inner diameter (axial center) side which is one radial side.
The sealing member 3 is annular and concentric with the shaft 9, and includes a core 30 and an elastic member 33 fixed to the core 30. The core 30 is made of metal, such as stainless steel or cold-rolled steel (SPCC), and is processed by sheet metal processing. The core 30 includes a core cylindrical portion 31 that constitutes a cylindrical portion that is fitted to an inner peripheral surface 4b of the outer peripheral member 4 that is the fixed member, and a core disk portion 32 that is connected to an end portion on one axial direction (external space) side of the core cylindrical portion 31 and is provided in an annular shape so as to protrude from the end portion toward the inner diameter side. In the illustrated example, the inner peripheral surface 4b of the outer peripheral member 4, into which the cylindrical portion of the sealing member 3 is fitted, is an inner peripheral surface of a step portion that is larger in diameter than the inner peripheral surface on the other axial direction (sealed space 8), but is not limited to this embodiment.

The elastic member 33 is made of a rubber material (elastic material) such as NBR, H-NBR, ACM, AEM, FKM, silicone rubber, or the like, and is integrally fixed to the core metal 30 over its entire periphery using a mold 1 described later.
The elastic member 33 is provided to cover the outer peripheral surface facing the outer diameter (diametrically outward) side, which is the other radial side, of the core metal cylindrical portion 31, and to cover one axial direction (external space) side of the core metal disc portion 32. The illustrated example shows an example in which the elastic member 33 is provided to cover the other axial direction (sealed space 8) end face of the core metal cylindrical portion 31. The illustrated example also shows an example in which the elastic member 33 is provided to cover the axial center side end face of the inner diameter side end of the core metal disc portion 32 and the side face of the sealed space 8.
The lip portion 34 of the elastic member 33 is provided so as to extend from the inner diameter side end portion toward the axial center of the core metal disc portion 32. The lip portion 34 is formed so that a middle portion on the axial center side, which is the tip side, is thinner than a portion near the inner diameter side end portion of the core metal disc portion 32, and the tip portion is shaped so as to bend toward the external space.

1(b), the sliding contact portion 35 provided to face the axial center side of the lip portion 34 is connected to the side surface of the sealed space 8 of the lip portion 34 and has a convex curved surface. An appropriate interference is set in the sealing member 3 so that the sliding contact portion 35 of the lip portion 34 comes into elastic contact with the outer peripheral surface 5b of the inner peripheral member 5.
The protrusions 36 of the sliding contact portion 35 are provided at equal intervals in the circumferential direction and protrude toward the axial center. The protrusions 36 are provided to extend over the entire axial direction of the sliding contact portion 35 provided to face the axial center. The protrusions 36 are provided so that a communication groove 37 that communicates the external space with the sealed space 8 is formed between adjacent protrusions 36, 36 when the sliding contact portion 35 is in elastic contact with the outer circumferential surface 5b of the inner circumferential member 5. The radial protrusion dimension of the protrusions 36 (groove depth dimension of the communication groove 37) and the circumferential dimension between adjacent protrusions 36, 36 (groove width dimension of the communication groove 37) may be appropriately determined so that the communication groove 37 as described above is formed to easily introduce lubricating oil into the communication groove 37, and from the viewpoint of suppressing the intrusion of wear powder of surrounding members into the sealed space 8. In the case where the protrusion dimension of the projection 36 and the groove width dimension of the communicating groove 37 are reduced toward the sealed space 8 as in the illustrated example, the protrusion dimension of the projection 36 and the groove width dimension of the communicating groove 37 at the portion in sliding contact with the outer circumferential surface 5b may be set to appropriate dimensions. Also, the projection 36 may be tapered toward the tip side in the protruding direction as viewed in the axial direction, may be approximately semicircular, or may have various other shapes.

As shown in FIG. 2(a), the mold 1 includes a first mold 10 having a concave-convex peripheral wall portion 15 that defines an annular cavity 19, in which concaves and convexes corresponding to the protrusions 36 and the communication grooves 37 of the sliding contact portion 35 of the lip portion 34 are alternately provided in the circumferential direction. The mold 1 also includes a second mold 20 in which an inner diameter side annular groove 26 that constitutes an annular groove that receives molding material overflowing from the cavity 19 is provided so as to extend in the circumferential direction and is adjacent to the inner diameter side as one radial side of the concave-convex peripheral wall portion 15 of the first mold 10. As shown in FIG. 4(a) and (b), the groove opening peripheral portion on the outer diameter side as the other radial side of the inner diameter side annular groove 26 of the second mold 20 is formed as a concave-convex corresponding portion 28, part of which is shaped according to the concave-convex peripheral wall portion 15 when viewed in the axial direction, and the other portion is formed as an arc-shaped arc portion 27. With this configuration, compared to when the groove opening periphery on the outer diameter side of the inner diameter side annular groove 26 of the second mold 20 is shaped to correspond to the uneven peripheral wall portion 15 of the first mold 10 over the entire circumference, the groove opening periphery on the outer diameter side of the inner diameter side annular groove 26 of the second mold 20 can be made into an arc shape over the majority, which makes it easier to process the mold 1 itself and reduces the cost of the mold 1. In addition, since a part of this groove opening periphery is made into the uneven corresponding portion 28 shaped to correspond to the uneven peripheral wall portion 15 of the first mold 10, burrs can be reduced at the portion made into the uneven corresponding portion 28, and when removing the burrs, the burrs are easily removed starting from that portion along the uneven shape of the tip of the lip portion 34, and the burrs remaining between the protrusions 36, 36 of the lip portion 34 can be reduced.

2(a) and 3, the first mold 10 is configured to have a first recess 11 that constitutes a cavity 19 and is provided in an annular shape. The first recess 11 is shaped according to the sealed space 8 side of the sealing member 3. The first recess 11 is provided with a first annular groove 12 that receives the core metal cylindrical portion 31 and forms the cylindrical portion of the sealing member 3. The first annular groove 12 is defined by a groove bottom surface 12a, an inner peripheral surface 12b facing the inner diameter side, and an outer peripheral surface 12c facing the outer diameter side. The diameter of the outer peripheral surface 12c is shaped according to the inner diameter of the core metal cylindrical portion 31. The first recess 11 is also provided with a mounting surface 13 on which the core metal disc portion 32 is placed, so as to be continuous with the outer peripheral surface 12c. The first recess 11 is also provided with a lip forming surface 14 that forms the sealed space 8 side of the lip portion 34, so as to be continuous with the mounting surface 13. The uneven peripheral wall portion 15 is provided so as to rise from the inner diameter end of the lip molding surface 14 toward the parting surface 18 of the mold 1.

2(b) and 3, the concave and convex peripheral wall portion 15 is provided with concave portions 16 corresponding to the protrusions 36 of the sliding contact portion 35 of the lip portion 34 and convex portions 17 corresponding to the communicating grooves 37 of the sliding contact portion 35, which are alternately provided in the circumferential direction. The concave portions 16 are provided so as to open toward the outer diameter side, and the convex portions 17 are provided so as to protrude toward the outer diameter side. In addition, these concave portions 16 and convex portions 17 are provided so as to extend in the axial direction from the inner diameter side end of the lip molding surface 14 to the parting surface 18 of the mold 1. In other words, the concave portions 16 are groove-shaped with one end in the groove longitudinal direction open on the parting surface 18. In the illustrated example, the concave portions 16 are shown as being approximately semicircular groove-shaped when viewed in the groove longitudinal direction (see also FIG. 4(b)). The tip surface of the convex portion 17 facing the outer diameter side is arc-shaped when viewed in the axial direction.

As shown in Fig. 2(a) and Fig. 4(a), the second mold 20 has a configuration in which a second recess 21 constituting the cavity 19 is provided in an annular shape. The second mold 20 also has an outer diameter side annular groove 22 extending in the circumferential direction, adjacent to the outer diameter side as the other radial side of the second recess 21, for receiving molding material overflowing from the cavity 19. The outer diameter side annular groove 22 has a substantially semicircular groove shape when viewed in the circumferential direction. The groove opening peripheral portions on both sides in the groove width direction of the outer diameter side annular groove 22 are provided so as to be continuous with the parting surface.
The second recess 21 is shaped according to the external space side of the sealing member 3. The second recess 21 is provided with a second annular groove 23 that receives the core metal disk portion 32 and molds the disk portion of the sealing member 3. The second annular groove 23 is defined by a groove bottom surface 23a provided to face the mounting surface 13 of the first mold 10, an inner peripheral surface 23b facing the inner diameter side, and an outer peripheral surface 23c facing the outer diameter side. The second recess 21 is provided with lip molding surfaces 24, 25 that face the lip molding surface 14 and the uneven peripheral wall portion 15 of the first mold 10 so as to be continuous with the outer peripheral surface 23c. The second recess 21 is provided with a lip tip molding surface 29 that is provided to be continuous with the lip molding surface 25 that faces the uneven peripheral wall portion 15, molds the tip surface of the lip portion 34 that faces the external space side, and constitutes a dividing surface.

The inner diameter side annular groove 26 of the second die 20 is formed into a substantially semicircular groove shape when viewed in the circumferential direction. The groove opening peripheral portion on the inner diameter side of the inner diameter side annular groove 26 is provided so as to be continuous with the parting surface, and the groove opening peripheral portion on the outer diameter side is provided so as to be continuous with the lip tip molding surface 29.
In this embodiment, as shown in Fig. 4B, the arc portion 27 of the inner diameter side annular groove 26 is provided so as to be located on the outer diameter side of the bottom imaginary circle 16b connecting the peripheral recessed bottoms 16a serving as the bottoms of the recesses 16 on the periphery of the dividing surface 18 side of the concave peripheral wall portion 15. In other words, the diameter D1 of the arc portion 27 is made larger than the diameter D2 of the bottom imaginary circle 16b. With this configuration, the arc portion 27 of the second mold 20 is located on the communicating groove 37 side of the most protruding portion of the projection 36 at the tip of the lip portion 34. Therefore, the burrs remaining between the projections 36, 36 of the lip portion 34 can be effectively reduced.

In this embodiment, the arc portion 27 is provided so as to coincide with the tip virtual circle 17b connecting the peripheral convex tip 17a as the tip of the convex portion 17 on the periphery of the dividing surface 18 side of the uneven peripheral wall portion 15, or to be located on the outer diameter side of the tip virtual circle 17b. In other words, the diameter D1 of the arc portion 27 is set to be equal to or larger than the diameter D3 of the tip virtual circle 17b. With this configuration, the arc portion 27 of the second mold 20 coincides with the groove bottom of the communicating groove 37 at the tip of the lip portion 34, or is located on the outer diameter side of the groove bottom. Therefore, there is almost no burr remaining between the protrusions 36, 36 of the lip portion 34. In this case, there is a concern that burrs will remain on one axial side of the tip of the lip portion 34, but since it is on the axial side and not the sliding surface side, it is a configuration that is unlikely to affect the performance of the sealing member 3. In the illustrated example, the diameter D1 of the arc portion 27 is slightly larger than the diameter D3 of the tip virtual circle 17b, but the diameter D1 of the arc portion 27 and the diameter D3 of the tip virtual circle 17b may be the same diameter.

The unevenness corresponding portion 28, which is shaped according to the uneven peripheral wall portion 15, is shaped according to the recess 16 on the dividing surface 18 side periphery of the uneven peripheral wall portion 15. With this configuration, burrs remaining around the unevenness corresponding portion 28 can be effectively reduced. The unevenness corresponding portion 28 is provided so as to block the opening of the recess 16 of the uneven peripheral wall portion 15 on the dividing surface 18 side and to protrude from the arc portion 27 toward the inner diameter side when viewed in the axial direction. That is, the unevenness corresponding portion 28 is substantially semicircular when viewed in the axial direction (when viewed from the bottom). In the illustrated example, the outer diameter of the unevenness corresponding portion 28 is slightly smaller than the inner diameter of the recess 16 on the dividing surface 18 side periphery, but this is not limited to this embodiment. In the illustrated example, the unevenness corresponding portion 28 is provided as a protruding stripe extending toward the groove bottom of the inner diameter side annular groove 26, but this is not limited to this embodiment, and may be, for example, a protruding piece.
In this embodiment, as shown in Fig. 4(a), the unevenness corresponding portions 28 are provided at multiple locations spaced apart in the circumferential direction. In the illustrated example, four unevenness corresponding portions 28 are provided at equal intervals. The arc portions 27 between these unevenness corresponding portions 28 are provided on the same circumference. The number and pitch of the unevenness corresponding portions 28 may be appropriate from the viewpoint of reducing the processing cost of the mold 1 and burrs, and may be at least one, or may be two or more.

When molding the sealing member 3 using the mold 1 as described above, the following procedure may be used.
For example, the core metal 30 is arranged so as to be aligned with the outer peripheral surface 12c of the first annular groove 12 and the mounting surface 13 of the first mold 10 installed on the lower side so that the first recess 11 opens upward (see the two-dot chain line in FIG. 2(a)). Then, a molding material such as a rubber sheet is placed on the core metal 30, and the second mold 20 installed on the upper side so that the second recess 21 opens downward is moved relative to the first mold 10 to bring the parting surfaces 18 into contact with each other, and the mold 1 is clamped, pressurized, and heated. By such compression molding, the elastic member 33 is fixed and integrated with the core metal 30, and the excess molding material overflows into the outer diameter side annular groove 22 and the inner diameter side annular groove 26. Then, the mold 1 is opened, and the parts overflowing into the outer diameter side annular groove 22 and the inner diameter side annular groove 26 and molded together with burrs are removed, and the sealing member 3 may be molded. The method of molding the sealing member 3 using the mold 1 is not limited to the above-described configuration, and various other modifications are possible.

Next, another embodiment of the mold according to the present invention will be described with reference to the drawings.
In the following embodiment, differences from the previously described embodiment will be mainly described, and the same components will be denoted by the same reference numerals and their description will be omitted or briefly described. Also, the description of the effects achieved similarly to the previously described embodiment will be omitted or briefly described.

5 and 6 are diagrams that diagrammatically show an example of a mold 1A according to the second embodiment.
The mold 1A according to this embodiment differs from the first embodiment in the configuration of an inner diameter side annular groove 26A of a second mold 20A.
In this embodiment, as shown in FIG. 6B, the arc portion 27A of the inner diameter side annular groove 26A is provided so as to be located on the inner diameter side of the tip imaginary circle 17b connecting the peripheral convex tips 17a of the concave-convex peripheral wall portion 15. In other words, the diameter D1 of the arc portion 27A is smaller than the diameter D3 of the tip imaginary circle 17b. With this configuration, the arc portion 27A of the second mold 20A is located on the inner diameter side of the groove bottom of the communicating groove 37 at the tip of the lip portion 34. Therefore, the part that is continuous with the part that overflows into the inner diameter side annular groove 26A in the part corresponding to the arc portion 27A of the protrusion 36 at the tip of the lip portion 34 can be effectively reduced, and it is possible to make it difficult for the protrusion 36 at the tip of the lip portion 34 to be damaged or insufficiently removed, which may occur during burr removal.

In the illustrated example, the diameter D1 of the arc portion 27A is the same as the diameter D2 of the bottom virtual circle 16b. With this configuration, it is possible to substantially eliminate the portion of the projection 36 at the tip of the lip portion 34 that is continuous with the portion that overflows into the inner diameter side annular groove 26A in the portion that corresponds to the arc portion 27A.
The unevenness corresponding portion 28A, which is shaped according to the uneven peripheral wall portion 15, is shaped according to the convex portion 17 on the peripheral edge of the divided surface 18 side of the uneven peripheral wall portion 15. With this configuration, burrs are not substantially generated between the protrusions 36, 36 of the lip portion 34 at the unevenness corresponding portion 28A, and burrs around the unevenness corresponding portion 28A can be effectively reduced. The unevenness corresponding portion 28A is shaped to receive the convex portion 17 on the peripheral edge of the divided surface 18 side of the uneven peripheral wall portion 15 when viewed in the axial direction, and is shaped to be recessed toward the outer diameter side from the arc portion 27. In the illustrated example, the unevenness corresponding portion 28A is a substantially rectangular recess when viewed in the axial direction (when viewed from the bottom), and is a groove-like shape that extends toward the groove bottom of the inner diameter side annular groove 26A. Also, as in the above, an example is shown in which four unevenness corresponding portions 28A are provided at equal intervals in the circumferential direction.
When this mold 1A is used, the sealing member 3 can be molded in the same manner as described above.

In each of the above embodiments, the outer diameter side annular groove 22 and the inner diameter side annular grooves 26, 26A are shown as examples having a substantially semicircular groove shape when viewed in the circumferential direction, but are not limited to this shape and may have various other shapes.
In addition, in each of the above-mentioned embodiments, an example is shown in which the inner peripheral side member 5 is rotated with respect to the outer peripheral side member 4, but instead of such a configuration, the outer peripheral side member 4 to which the sealing member 3 is fitted may be rotated. In addition, in each of the above-mentioned embodiments, the mold 1, 1A for molding the sealing member 3 having the outer peripheral surface 5b of the inner peripheral side member 5 as the first surface and the lip portion 34 that slides against this surface is illustrated, but instead of such a configuration, the mold 1, 1A for molding the sealing member 3 having the inner peripheral surface 4b of the outer peripheral side member 4 as the first surface and the lip portion 34 that slides against this surface may be used. In other words, the mold 1, 1A may be used to mold the sealing member 3 in which the lip portion 34 is provided so as to extend toward the outer diameter side. In this case, it is sufficient to grasp that one radial side of the above-mentioned mold 1, 1A is the outer diameter side, and the other radial side is the inner diameter side. In other words, the above-mentioned arc portion or uneven corresponding portion may be provided on the groove opening periphery on the inner diameter side of the outer diameter side annular groove 22 adjacent to the outer diameter side of the uneven peripheral wall portion 15 of the first mold 10. The configurations of the components constituting the molds 1, 1A according to the above-mentioned embodiments are not limited to the examples described above, and various other modifications are possible.

Reference Signs List 1, 1A Mold 10 First mold 15 Concave peripheral wall portion 16 Recess 16a Peripheral recessed bottom portion (bottom portion of recess on peripheral portion on parting surface side)
16b Bottom virtual circle (virtual circle connecting the peripheral concave bottoms)
17 Convex portion 17a Peripheral convex tip (tip of the convex portion on the peripheral edge on the dividing surface side)
17b Tip virtual circle (virtual circle connecting the peripheral convex tips)
18 Parting surface 19 Cavity 20, 20A Second mold 26, 26A Inner diameter side annular groove (annular groove)
27, 27A: Arc portion 28, 28A: Concave-convex corresponding portion (portion shaped to correspond to the concave-convex peripheral wall portion)
3 Sealing member 34 Lip portion 35 Sliding contact portion 36 Protrusion 37 Communication groove 4 Outer peripheral member 4b Inner peripheral surface 5 Inner peripheral member 5b Outer peripheral surface (first surface)
8. Sealed Space

Claims (4)

A mold used for molding a sealing member, in which a plurality of protrusions are provided around an entire circumference at intervals in the circumferential direction on a sliding contact portion of an annular lip portion that is in sliding contact with a first surface of an inner circumferential surface of an outer circumferential surface side member and an outer circumferential surface of an inner circumferential surface side member that are opposed in a radial direction, so as to define a communication groove that communicates a sealed space with an external space,
a first mold having a concave-convex peripheral wall portion which defines an annular cavity and in which concave-convex projections corresponding to the projections of the sliding contact portion of the lip portion and the communicating grooves are alternately provided in the circumferential direction; and a second mold adjacent to one radial side of the concave-convex peripheral wall portion of the first mold, and having an annular groove extending in the circumferential direction for receiving molding material overflowing from the cavity,
a groove opening peripheral portion on the other radial side of the annular groove has a part shaped according to the concave-convex peripheral wall portion as viewed in the axial direction, and another part is an arc-shaped portion;
A mold characterized in that the arc portion of the annular groove is provided so as to be located radially on the other side of an imaginary circle connecting the bottoms of the recesses on the dividing surface side peripheral edge of the concave-convex peripheral wall portion . A mold used for molding a sealing member, in which a plurality of protrusions are provided around an entire circumference at intervals in the circumferential direction on a sliding contact portion of an annular lip portion that is in sliding contact with a first surface of an inner circumferential surface of an outer circumferential surface side member and an outer circumferential surface of an inner circumferential surface side member that are opposed in a radial direction, so as to define a communication groove that communicates a sealed space with an external space,
a first mold having a concave-convex peripheral wall portion which defines an annular cavity and in which concave-convex projections corresponding to the projections of the sliding contact portion of the lip portion and the communicating grooves are alternately provided in the circumferential direction; and a second mold adjacent to one radial side of the concave-convex peripheral wall portion of the first mold, and having an annular groove extending in the circumferential direction for receiving molding material overflowing from the cavity,
a groove opening peripheral portion on the other radial side of the annular groove has a part shaped according to the concave-convex peripheral wall portion as viewed in the axial direction, and another part is an arc-shaped portion;
the arc portion of the annular groove is provided so as to coincide with an imaginary circle connecting tips of the convex portions of the dividing surface side peripheral edge of the concave-convex peripheral wall portion or to be located on the other radial side of the imaginary circle,
A mold characterized in that the portion of the annular groove shaped to correspond to the uneven peripheral wall portion is shaped to correspond to a recess on the dividing surface side peripheral edge of the uneven peripheral wall portion. A mold used for molding a sealing member, in which a plurality of protrusions are provided around an entire circumference at intervals in the circumferential direction on a sliding contact portion of an annular lip portion that is in sliding contact with a first surface of an inner circumferential surface of an outer circumferential surface side member and an outer circumferential surface of an inner circumferential surface side member that are opposed in a radial direction, so as to define a communication groove that communicates a sealed space with an external space,
a first mold having a concave-convex peripheral wall portion which defines an annular cavity and in which concave-convex projections corresponding to the projections of the sliding contact portion of the lip portion and the communicating grooves are alternately provided in the circumferential direction; and a second mold adjacent to one radial side of the concave-convex peripheral wall portion of the first mold, and having an annular groove extending in the circumferential direction for receiving molding material overflowing from the cavity,
a groove opening peripheral portion on the other radial side of the annular groove has a part shaped according to the concave-convex peripheral wall portion as viewed in the axial direction, and another part is an arc-shaped portion;
the arc portion of the annular groove is provided so as to be located on one radial side of an imaginary circle connecting tips of the convex portions of the dividing surface side peripheral edge of the concave-convex peripheral wall portion,
A mold characterized in that the portion of the annular groove shaped to correspond to the uneven peripheral wall portion is shaped to correspond to the convex portion of the dividing surface side peripheral edge of the uneven peripheral wall portion. In claim 2 or 3 ,
A mold characterized in that the arc portion of the annular groove is provided so as to be located radially on the other side of an imaginary circle connecting the bottoms of the recesses on the dividing surface side peripheral edge of the concave-convex peripheral wall portion.

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