JP7291442B1 - Resin-molded member and manufacturing method thereof - Google Patents

Abstract

Kind Code: A1 In a resin molded member having an undercut portion such as an annular groove on the inner peripheral surface, when joining primary molded products divided by the undercut portion by secondary molding, unnecessary injection pressure and heat in the secondary molding are required. suppress deformation. A resin-molded member (1) is formed by fitting a first tubular portion (10) and a second tubular portion (20), which are primary molded products, and joining them by secondary molding. The molded resin member 1 has a through hole 2 passing through the insides of the first tubular portion 10 and the second tubular portion 20 , and an undercut-shaped annular groove 3 opens on the inner peripheral surface of the through hole 2 . Further, a recessed groove 6 into which a molding material for secondary molding is injected is opened on the outer peripheral surface. The concave groove 6 and the annular groove 3 are formed by facing the end surface of the first cylindrical portion 10 and the end surface of the second cylindrical portion 20 with a gap therebetween. The portion where the first cylindrical portion 10 and the second cylindrical portion 20 are fitted has a shape in which the position of the concave groove 6 is shifted from the annular groove 3 . Do not participate in forming positions. [Selection drawing] Fig. 3

Description

TECHNICAL FIELD The present invention relates to a molded resin member having an undercut shape on its inner peripheral surface and a method for manufacturing the same.

In the drive mechanism of cars, airplanes, ships, drones, etc., the main rotating shaft of the motor and shaft members used for hydraulic brakes are inserted into the through holes of the resin molded members, and oil or lubrication is performed by sealing materials such as O-rings. It has a structure that prevents the outflow of liquids, liquid fuels, and other liquids and gases, and is waterproof and dustproof from the outside. In addition, a structure is employed in which a bearing member is arranged on the inner peripheral surface of the through hole to improve slidability. A resin-molded member used in this type of structure has an annular groove formed on the inner peripheral surface of the through hole for arranging a sealing material and a bearing member.

Conventionally, as a method of forming an undercut shape such as an annular groove on the inner peripheral surface of a through hole, there is a method of inserting a cutter into the prepared hole and cutting the undercut shape. Alternatively, there is a method in which the inner core of the mold for molding is divided, and an undercut shape is formed on the inner peripheral surface of the through hole using a slide core that slides in a direction intersecting the mold opening direction.

In addition, a structure is adopted in which a bearing is attached to the inner peripheral surface of a through-hole into which the rotating main shaft of the motor is inserted to enhance the slidability of the shaft member. This kind of structure has an undercut shape in the space for arranging the bearing. Therefore, conventionally, by dividing the resin molded member at the mounting position of the bearing and molding it, a part without an undercut shape is manufactured. It is manufactured by a method of joining by ultrasonic welding or laser welding.

In Patent Documents 1 and 2, when manufacturing a hollow or cylindrical resin molded member having an undercut shape on the inner peripheral surface, a primary molded product divided into shapes without the undercut shape is manufactured, and the primary molding is performed. A manufacturing method is described for butting and joining articles. In the resin-molded member (hollow assembly) of Patent Document 1, parts such as valves are attached to the undercut-shaped portion. In the manufacturing methods of Patent Literatures 1 and 2, the primary molded products are joined by injecting a molding material in the secondary molding onto the outer peripheral surface of the portion where the two primary molded products are butted together, and hardening the molding material.

JP-A-7-217755 JP-A-2003-326551

When an undercut shape for attaching a sealing material or a bearing is formed by cutting on the inner peripheral surface of the through hole, a machining mark remains. Therefore, the adhesion of the sealing material is lowered, and the airtightness cannot be ensured. Further, when the split core is used to form the undercut shape, a parting line, which is a mark of the split line of the slide core, is formed on the inner surface of the undercut shape. Therefore, the adhesion of the sealing material is lowered, and the airtightness cannot be ensured. Therefore, there is a risk of leakage or intrusion of gases and liquids.

A primary molded product is manufactured by dividing a resin molded member with an undercut shape on the inner peripheral surface of a through hole at the position of the undercut shape, and after inserting a seal material or bearing from the divided surface, the divided surfaces are butted and welded. In this case, there is no problem of deterioration of airtightness due to working marks or parting lines, but there is a possibility that welding burrs may form at the joints. Also, it is difficult to assemble split parts and enclosed parts (such as bearings) with high coaxiality.

In the manufacturing method in which divided primary molded products are joined by secondary molding as in Patent Documents 1 and 2, injection pressure is applied to joints. Therefore, deformation due to injection pressure becomes a problem. In the manufacturing method of Patent Document 1, injection pressure is applied directly to the parts (valve unit) enclosed in the joint. Therefore, there is a risk of deformation of the part due to heat and injection pressure. Further, in Patent Document 2, injection pressure is applied directly to a portion (parting surface) where the primary molded products are abutted. Therefore, there is a risk that the molding material will enter through the gaps between the dividing surfaces and form burrs. In addition, in neither of Patent Documents 1 and 2, the mold for secondary molding does not have a structure capable of supporting the portion that receives the injection pressure from the inside. Therefore, there is a risk that the portion that receives the injection pressure will be deformed by the heat and the injection pressure.

As a method of manufacturing a resin-molded member in which a sealing material and a bearing are attached to the inner peripheral surface of a through hole, there is a method of placing the sealing material and the bearing in a mold and performing insert molding, in addition to the above method. However, insert molding has problems such as deformation of the sealing material due to injection pressure during molding, and resin covering of the sealing material and bearings.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a resin-molded member having an undercut portion on the inner peripheral surface of a through-hole and a method of manufacturing the same so as to prevent machining marks and parting lines from forming in the undercut portion. That's what it is. Another object of the present invention is to prevent resin burrs due to secondary molding, and to avoid deformation of undercut portions due to injection pressure and heat during secondary molding.

In order to solve the above problems, a first aspect of the present invention is a resin-molded member provided with a through hole in which a shaft member is arranged, comprising: a first cylindrical portion; a second cylindrical portion that fits inside and extends coaxially with the first cylindrical portion; and an inner peripheral surface of the through hole that extends axially inside the first cylindrical portion and the second cylindrical portion. An undercut portion that is recessed toward the outer periphery is opened in the first cylindrical portion, and the undercut portion is fitted to the bottom surface of a first annular recess that is recessed in the axial direction from the end surface of the first cylindrical portion and the first annular recess. It is a gap in the axial direction between the end surface of the second cylindrical portion, and a concave groove formed by the end surface of the first cylindrical portion and the second cylindrical portion is formed on the outer peripheral side of the second cylindrical portion in the circumferential direction. and a bonding resin portion for bonding the first cylindrical portion and the second cylindrical portion is arranged in the concave groove.

A second aspect of the present invention is a resin-molded member provided with a through hole in which a shaft member is arranged, the first tubular portion and one end being fitted inside the first tubular portion, the above-mentioned a second cylindrical portion extending coaxially with the first cylindrical portion; a third cylindrical portion extending coaxially with the first cylindrical portion and the second cylindrical portion in which the other end of the second cylindrical portion is fitted; and an undercut portion recessed toward the outer peripheral side opens on the inner peripheral surface of the through hole extending in the axial direction inside the first tubular portion, the second tubular portion, and the third tubular portion, The undercut portion includes a first coupling portion in which the second tubular portion is fitted inside the first tubular portion, and a second coupling portion in which the second tubular portion is fitted inside the third tubular portion. The undercut portions provided in the first coupling portion are provided at two locations of the portion and are formed by the bottom surface of a first annular recess recessed from the end surface of the first cylindrical portion toward one side in the axial direction, and the first annular recess portion. The undercut portion, which is a gap in the axial direction between the end surface of the second cylindrical portion fitted in the recess and is provided on the second coupling portion, extends from the end surface of the third cylindrical portion in the axial direction. The gap in the axial direction between the bottom surface of the second annular recess recessed on the other side of the second annular recess and the end face on the other end side of the second cylindrical portion fitted in the second annular recess, and the outer periphery of the second cylindrical portion A groove formed by the end surface of the first cylindrical portion, the outer peripheral surface of the second cylindrical portion, and the end surface of the third cylindrical portion extends in the circumferential direction on the side, and the groove includes the above-mentioned A bonding resin portion for bonding the first cylindrical portion and the third cylindrical portion is arranged with respect to the second cylindrical portion.

Further, the present invention is a method of manufacturing a resin molded member provided with a through hole in which a shaft member is arranged, comprising: a primary molding step of molding a first tubular portion and a second tubular portion; and a second mold for holding the second cylindrical portion are clamped in the axial direction of the first cylindrical portion and the second cylindrical portion, so that the inner side of the first cylindrical portion One end of the second cylindrical portion is fitted and coaxially coupled, and the first cylindrical portion, the second cylindrical portion, and the mold surface are placed in a mold having the first mold and the second mold. A secondary molding preparation step of forming an enclosed secondary molding cavity on the outer peripheral side of the second cylindrical portion , and injecting a molding material into the secondary molding cavity to form the first cylindrical portion and the second cylindrical portion. and a secondary molding step of molding a bonding resin portion for bonding the portions, and in the secondary molding preparation step, the first annular recess recessed in the axial direction from the end surface of the first cylindrical portion is formed inside the first annular recess. One ends of the two cylindrical portions are fitted, and the axial direction is inserted between the bottom surface of the first annular recess and the end surface of the second cylindrical portion.
An undercut portion recessed toward the outer periphery is formed on the inner peripheral surface of the through hole extending in the axial direction inside the first tubular portion and the second tubular portion by forming a gap in the direction of the and

According to the present invention, the resin molded member is manufactured by assembling the primary molded products (the first cylindrical portion and the second cylindrical portion) divided at the positions of the undercut portions. It can be manufactured using a manufacturing method that does not leave processing marks or parting lines. Therefore, it is possible to eliminate working traces and parting lines from the undercut portion of the finished resin-molded member.

Further, according to the present invention, when connecting the primary molded products (the first cylindrical portion and the second cylindrical portion), the end surface of the first cylindrical portion that fits on the outer peripheral side of the second cylindrical portion, and the second cylindrical portion Since a recess (groove) surrounded by is formed, the mold can be configured so that this recess serves as a cavity for secondary molding. Therefore, the joining resin portion can be molded by secondary molding to join the first cylindrical portion and the second cylindrical portion. Further, with this structure, the concave groove is arranged at a position shifted in the axial direction from the undercut portion by the insertion length of the second tubular portion into the first tubular portion. Therefore, injection pressure and heat are not applied to the butted portions (parting surfaces) of the primary molded products, so that it is possible to avoid the formation of resin burrs inside the through holes and undercut portions. In addition, since the undercut part is displaced from the position where injection pressure and heat are applied, deformation of the undercut part due to injection pressure and heat of secondary molding and deformation of parts inserted into the undercut part should be avoided. can be done.

In the present invention, the undercut portion is an annular groove extending in the circumferential direction. In this case, the annular groove can be used as an arrangement space for a sealing material or a bearing member interposed between the shaft member and the shaft member. By doing so, the seal material and the bearing member can be continuously incorporated in the inner peripheral surface of the through hole over the entire circumference. Therefore, it is possible to secure the airtightness of the portion through which the shaft member is passed by the sealing material, and to suppress leakage and intrusion of gas and liquid. Alternatively, the bearing member can enhance the slidability of the shaft member.

In the present invention, it is preferable that the concave groove does not overlap the undercut portion when viewed from the radial direction. By completely displacing the recessed groove and the undercut portion in this way, it is possible to avoid deformation of the portion where the thickness is reduced due to the provision of the undercut portion due to the injection pressure and heat of the secondary molding. At the same time, it is possible to avoid deformation of parts arranged in the undercut portion. For example, deformation of the sealing material can be avoided. Further, when the undercut portion is an annular groove, it is possible to suppress a decrease in adhesion of the sealing material due to a decrease in shape accuracy of the annular groove.

For example, in the present invention, a configuration including an O-ring arranged in the annular groove can be adopted. In this case, it is preferable that the inner surface of the annular groove be free of parting lines and machining marks. By doing so, when the O-ring is assembled, it is possible to suppress a decrease in the degree of adhesion due to processing marks and parting lines. Therefore, airtightness can be ensured.

In the present invention, when adopting a configuration including a bearing member arranged in the annular groove,
The slidability of the shaft member can be enhanced. In this case, for example, the bearing member is a bearing that includes a plurality of rolling elements arranged in the annular groove, and a rolling element holding portion that holds the plurality of rolling elements at positions arranged at predetermined intervals in the circumferential direction. Preferably. With this configuration, the rolling elements can be brought into contact with the outer peripheral surface of the shaft member inserted into the through hole. Therefore, the slidability in the axial direction and the slidability in the circumferential direction of the shaft member can be enhanced.

In this case, it is preferable that the rolling element holding portion includes partition walls arranged radially in the annular groove, and the partition walls are formed integrally with the inner surface of the annular groove. By forming the rolling element holding portion integrally with the tubular portion in this manner, the rolling element holding portion (partition wall) is formed before one of the two tubular portions is fitted inside the other. The bearing can be incorporated into the annular groove only by performing the work of dropping the rolling elements between the partition walls adjacent in the circumferential direction to the cylindrical portion on the side where the bearing is formed, and then fitting the two cylindrical portions together. . Therefore, it is possible to construct a bearing that has a small number of parts and is easy to assemble.

Further, when the rolling element holding portion has a partition, the surface of the partition is curved or bent in a shape along the outer peripheral surface of the rolling element arranged between the partitions adjacent in the circumferential direction. can be Alternatively, the rolling element holding portion may be configured to include ribs extending from the inner peripheral side end portion of the partition wall to both sides in the circumferential direction. By doing so, it is possible to prevent the rolling elements from falling inside the through hole. Moreover, the rolling elements can be stably held, and the slidability of the shaft member can be enhanced.

In the present invention, it is preferable that the annular groove has a pair of annular surfaces facing each other in the axial direction, and has a retainer projection protruding in the axial direction from the inner peripheral edge of at least one of the pair of annular surfaces. Alternatively, in the present invention, the annular groove has a pair of annular surfaces facing each other in the axial direction, and at least one of the pair of annular surfaces is spaced from the other of the pair of annular surfaces toward the inner peripheral side. It is preferable to provide an inclined surface that is inclined in a direction in which the width is narrowed. With this configuration, the inclined surface and the retaining projection can prevent the sealing member and the bearing member from coming off. For example, it is possible to prevent O-rings and rolling elements forming a bearing member from coming off.

1st form of this invention WHEREIN: It is preferable that a said 1st cylinder part is provided with the contact surface which contacts the end of a said 2nd cylinder part, and the said axial direction. Alternatively, in the second aspect of the present invention, the first cylindrical portion includes a first contact surface that contacts one end of the second cylindrical portion in the axial direction, and the third cylindrical portion It is preferable to provide a second contact surface that contacts the other end of the portion in the axial direction. By aligning the end faces of the primary molded product and positioning them in this manner, the dimensional accuracy of the opening height of the undercut portion such as the annular groove can be improved.

In the method of manufacturing a resin molded member according to the present invention, in the secondary molding preparation step, a sealing material or a bearing member is placed inside the first annular recess, and then one end of the second cylindrical portion is attached to the first annular recess. It is preferable that the sealing material or the bearing member is held in the annular groove by fitting into the recess. In this way, the sealing material and bearing member can be easily incorporated into the annular groove. Also, the sealing material and the bearing member are less likely to fall out of the annular groove.

In the method for manufacturing a resin molded member of the present invention, in the secondary molding preparation step, the first cylindrical portion and the second cylindrical portion are separated from each other by arranging mold pins inside the first cylindrical portion and the second cylindrical portion. It is preferable that the cylindrical portion is positioned coaxially and the secondary molding cavity is formed at a position that does not overlap with the annular groove when viewed from the radial direction. By doing so, the degree of coaxiality between the first cylindrical portion and the second cylindrical portion can be increased. Also, the injection pressure of the secondary molding can be received by the mold pins. Therefore, it is possible to avoid deformation of the part to which the injection pressure of the secondary molding is applied.

In the method for manufacturing a resin molded member of the present invention, in the secondary molding step, a thermosetting resin as the molding material is filled into the secondary molding cavity and heated to cause a crosslinking reaction of the thermosetting resin. It is preferable that the bonding resin portion is bonded to the first cylindrical portion and the second cylindrical portion by. By doing so, the bonding strength of the bonding resin portion can be increased.

In the method of manufacturing a resin molded member of the present invention, it is preferable that in the secondary molding step, the first mold and the second mold are clamped while injecting the molding material into the secondary molding cavity. By doing so, even if a sink mark is formed on the end surface of the primary molded product, the sink mark can be improved by the injection pressure of the secondary molding.

According to the present invention, the resin-molded member is formed by combining the primary molded products (the first cylindrical portion and the second cylindrical portion) divided at the positions of the undercut portions. Machining traces and parting lines can be eliminated from. In addition, the recessed groove for connecting the primary molded products (the first cylindrical portion and the second cylindrical portion) by secondary molding has a length corresponding to the insertion length of the second cylindrical portion into the first cylindrical portion from the undercut portion. It is arranged in an axially offset position. Therefore, since the injection pressure is not applied directly to the parting surface of the primary molded product, it is possible to avoid the formation of resin burrs inside the through holes and undercut portions. In addition, deformation of the undercut portion due to the injection pressure of the secondary molding and deformation of the parts incorporated in the undercut portion can be avoided.

FIG. 2 is a cross-sectional view showing a usage state of the resin-molded member of Embodiment 1; 3 is a cross-sectional view of a primary molded product used for manufacturing the resin molded member of Embodiment 1. FIG. 4A to 4C are diagrams for explaining a manufacturing process of the resin-molded member of Embodiment 1. FIG. 5 is a cross-sectional view of a resin-molded member of Embodiment 2. FIG. FIG. 11 is a cross-sectional view of a resin-molded member of Embodiment 3; FIG. 10 is a cross-sectional view of a resin-molded member of Embodiment 4; FIG. 11 is a cross-sectional view of a resin-molded member of Embodiment 5; FIG. 12 is a cross-sectional view of a resin-molded member of Embodiment 6; FIG. 10 is a cross-sectional view of a resin-molded member cut at the position of the bearing member of Modification 1; FIG. 11 is a cross-sectional view of a resin molded member cut at the position of the bearing member of Modification 2;

The molded resin member of the present invention is a molded product manufactured by injection molding using a mold. The resin molded member has a through hole in which the shaft member is arranged, and an undercut shape is provided on the inner peripheral surface of the through hole. In the embodiments described below, the undercut shape is an annular groove in which a seal or bearing member is arranged. The resin-molded member according to the present invention can be used, for example, in automobiles, airplanes, ships, drones, etc., by inserting a shaft member used for a rotating main shaft of a motor or a hydraulic brake into a through-hole of the resin-molded member, and attaching an O-ring or the like. Sealing materials are used for structures that prevent outflow of liquids such as oil, lubricating liquids, and liquid fuels, and gases, and are waterproof and dustproof from the outside. Alternatively, it is used in a structure in which a rotating main shaft of a motor, a shaft member used for a hydraulic brake, etc. is inserted into a through hole of a resin molded member, and a bearing member such as a bearing or an oilless bush increases the slidability of the shaft member. It is.

In addition, the present invention is not limited to resin molded members in which the undercut shape (undercut portion) is an annular groove. The undercut shape may be a recess of any shape that opens to the inner peripheral surface of the through hole. For example, the undercut shape may be an arcuate groove formed partially in the circumferential direction. Further, the external shape of the resin-molded member is not limited to a cylindrical shape. For example, it may be prismatic. Also, the configurations of the embodiments and modifications described below can be combined as appropriate. For example, both an annular groove for arranging the seal material and an annular groove for arranging the bearing member may be provided on the inner peripheral surface of the molded resin member.

(Embodiment 1)
FIG. 1 is a cross-sectional view showing how the resin molded member 1 of Embodiment 1 is used. The molded resin member 1 is cylindrical. A shaft member 100 is arranged in the through hole 2 passing through the radial center of the resin molded member 1 . The shaft member 100 is supported so as to be slidable in the axial direction inside the through hole 2 or rotatable around the axis. A seal member 4 is held in an annular groove 3 provided on the inner peripheral surface of the through hole 2 . The seal member 4 is an O-ring, and is radially compressed between the inner peripheral surface of the annular groove 3 and the outer peripheral surface of the shaft member 100 .

In this specification, the direction along the central axis L of the through hole 2 is defined as the axial direction, one side of the axial direction is defined as L1, and the other side of the axial direction is defined as L2. FIG. 1 is a cross-sectional view of the resin molded member 1 and the shaft member 100 taken along a plane including the central axis L. FIG.

The resin molded member 1 includes a first tubular portion 10 and a second tubular portion 20 extending in the axial direction. The molded resin member 1 is obtained by joining a plurality of primary molded products (the first cylindrical portion 10 and the second cylindrical portion 20) by secondary molding. The second cylindrical portion 20 has one end fitted inside the first cylindrical portion 10 and extends coaxially with the first cylindrical portion 10 . The through hole 2 extends axially inside the first tubular portion 10 and the second tubular portion 20 .

The molded resin member 1 includes a coupling portion 5 in which the end portion of the second cylindrical portion 20 on the one side L1 is fitted inside the end portion on the other side L2 of the first cylindrical portion 10 . The molded resin member 1 includes an annular groove 3 located on the inner peripheral side of the coupling portion 5 and a concave groove 6 located on the outer peripheral side of the coupling portion 5 . The first tubular portion 10 and the second tubular portion 20 are joined by the joining resin portion 7 which is filled in the concave groove 6 by secondary molding and hardened. The concave groove 6 is arranged at a position shifted to the other side L2 in the axial direction with respect to the annular groove 3 . In this embodiment, the position of the groove 6 is shifted to a position where the groove 6 and the annular groove 3 do not overlap when viewed in the radial direction. The annular groove 3 is formed at a location where the inner peripheral portion of the end surface of the other side L2 of the first cylindrical portion 10 and the inner peripheral portion of the end surface of the one side L1 of the second cylindrical portion 20 face each other with a gap in the axial direction. is. The recessed groove 6 is formed at a location where the outer peripheral portion of the end surface of the other side L2 of the first cylindrical portion 10 and the outer peripheral portion of the end surface of the one side L1 of the second cylindrical portion 20 face each other with a gap in the axial direction. is.

FIG. 2 is a cross-sectional view of a primary molded product (the first cylindrical portion 10 and the second cylindrical portion 20) used for manufacturing the molded resin member 1 of Embodiment 1. FIG. As shown in FIG. 2, the end portion of the first cylindrical portion 10 on the other side L2 has an annular tip surface 11 and a first annular recess 12 recessed from the inner peripheral edge of the tip surface 11 toward the one side L1 in the axial direction. Prepare. The first annular recessed portion 12 has an inner peripheral surface 13 and an annular bottom surface 14 connected to the end of the inner peripheral surface 13 on one side L1. The inner peripheral surface 13 includes a small-diameter cylindrical surface 15 connected to the bottom surface 14, a large-diameter cylindrical surface 16 arranged on the other side L2 of the small-diameter cylindrical surface 15 and connected to the tip end surface 11, the small-diameter cylindrical surface 15 and the large-diameter cylindrical surface 16. It has an annular step surface 17 that connects with the diametrical cylindrical surface 16 .

The end of the second cylindrical portion 20 on the one side L1 includes an annular tip surface 21 and an annular surface 22 recessed from the tip surface 21 toward the other side L2 in the axial direction on the inner peripheral side of the tip surface 21. , a cylindrical surface 23 connecting the distal surface 21 and the annular surface 22 . The outer peripheral surface of the second tubular portion 20 is provided with a second annular recessed portion 24 that is recessed from the outer peripheral edge of the tip end surface 21 toward the other side L2 in the axial direction. The second annular recessed portion 24 has a side surface 25 extending in the axial direction and an annular bottom surface 26 extending outward from the end of the side surface 25 on the other side L2.

As shown in FIG. 2, at the tip of one side L1 of the second tubular portion 20, a cylindrical rib 27 composed of the tip surface 21, the cylindrical surface 23, and the side surface 25 of the second annular recess 24 is arranged. . As shown in FIG. 1, at the connecting portion 5 between the first tubular portion 10 and the second tubular portion 20, the cylindrical rib 27 is the first
It is fitted inside the large-diameter cylindrical surface 16 of the cylindrical portion 10 . A tip surface 21 of the cylindrical rib 27 abuts the annular stepped surface 17 of the first cylindrical portion 10 in the axial direction. As a result, on the inner peripheral side of the cylindrical rib 27, the annular surface 22 of the second tubular portion 20 and the bottom surface 14 of the first annular concave portion 12 of the first tubular portion 10 face each other with a gap in the axial direction. and this gap forms the annular groove 3 . The cylindrical surface 23 of the second cylindrical portion 20 and the small-diameter cylindrical surface 15 of the first cylindrical portion 10 constitute the inner peripheral surface of the annular groove 3 .

As shown in FIG. 2 , the distal end of the first cylindrical portion 10 on the other side L2 is composed of the distal end surface 11 , the large-diameter cylindrical surface 16 of the first annular recess 12 , and the outer peripheral surface 18 of the first cylindrical portion 10 . cylindrical ribs 19 are arranged. As shown in FIG. 2 , the cylindrical rib 19 is fitted on the outer peripheral side of the second annular concave portion 24 of the second tubular portion 20 . As described above, as a result of axial contact between the distal end surface 21 of the second cylindrical portion 20 and the annular step surface 17 of the first cylindrical portion 10 , the cylindrical rib 19 is formed on the outer peripheral surface of the second cylindrical portion 20 . and the bottom surface 26 of the second annular recess 24 face each other with a predetermined gap in the axial direction, and this gap forms the groove 6 . A side surface 25 of the second annular recessed portion 24 constitutes an inner peripheral surface of the recessed groove 6 .

(Production method)
3A and 3B are diagrams for explaining the manufacturing process of the resin-molded member 1 of the first embodiment. In FIG. 3, ST1 is a primary molding process, ST2 is a secondary molding preparation process, ST3 is a secondary molding process, and ST4 is a mold release process.

First, in the primary molding step ST1, the first tubular portion 10 and the second tubular portion 20, which are primary molded products, are molded. As shown in FIG. 3, the first tubular portion 10 is molded using a primary molding die that includes a first die C10 and a core die C11. The second tubular portion 20 is molded using a primary molding die that includes a second die C20 and a core die C21. The first cylindrical portion 10 and the second cylindrical portion 20 are formed by dividing the molded resin member 1 with a dividing surface that connects the annular groove 3 and the concave groove 6 . Therefore, since both the first cylindrical portion 10 and the second cylindrical portion 20 have a shape in which an undercut portion cannot be formed on the inner peripheral surface of the through hole 2, it is necessary to divide the core molds C11 and C21 for forming the through hole 2. There is no Therefore, no parting line is formed in the through hole 2 and the annular groove 3 .

Next, in the secondary molding preparation step ST2, the first tubular portion 10 is released from the core mold C11, and the second tubular portion 20 is released from the core mold C21. Then, the first cylindrical portion 10 held by the first mold C10 and the second cylindrical portion 20 held by the second mold C20 are coaxially positioned by the mold pins C30. Then, by clamping the first mold C10 and the second mold C20, the first tubular portion 10 and the second tubular portion 20 are fitted. The second cylindrical portion 20 is inserted to a position where the tip end surface 21 of the second cylindrical portion 20 abuts against the annular stepped surface 17 of the first cylindrical portion 10 to form the annular groove 3 in the inner peripheral surface of the through hole 2 . A concave groove 6 is formed on the outer peripheral surface of the cylindrical portion 20 .

In the secondary molding preparation step ST2, before the first mold C10 and the second mold C20 are clamped to fit the first cylinder part 10 and the second cylinder part 20, the first cylinder part 10 of the first cylinder part 10 is formed. A sealing material 4 is dropped into the annular concave portion 12 . As a result, the sealing material 4 is held in the annular groove 3 in the finished resin molded member 1 .

The mold for secondary molding has a mold surface S that closes the opening of the groove 6 . In the secondary molding preparation step ST2, the concave groove 6 and the mold surface S form the secondary molding cavity C. As shown in FIG. In the example of the mold shown in FIG. 3, the secondary molding cavity C is formed by the mold surface S of the first mold C10. The configurations of the mold for primary molding and the mold for secondary molding are not limited to the configurations shown in FIG. For example, the mold surface S that forms the secondary molding cavity C can also be provided on the second mold C20. Alternatively, a slide mold may be arranged between the first mold C10 and the second mold C20, and the secondary molding cavity C may be formed using the mold surface of the slide mold.

Subsequently, in the secondary molding step ST3, a molding material is injected into the secondary molding cavity C from a gate (not shown) and cured to mold the bonding resin portion 7 . The molding material may be a thermoplastic resin or a thermosetting resin. When a thermoplastic resin is used, the heat of the molding material melts the interfaces between the first cylindrical portion 10 and the second cylindrical portion 20 to integrate them with the bonding resin portion 7 . Further, when a thermosetting resin is used, by heating after filling the molding material, a cross-linking reaction proceeds at the interface between the molding material and the first cylindrical portion 10 and the second cylindrical portion 20, and the bonding resin portion 7 and the bonding resin portion 7 are formed. unify. Thereby, the bonding strength of the bonding resin portion 7 can be increased.

In the secondary molding step ST3, the first die C10 and the second die C20 are clamped while injecting the molding material into the cavity C for secondary molding. As described above, in the secondary forming preparation step ST2, the tip surface 21 of the second cylindrical portion 20 abuts against the annular stepped surface 17 of the first cylindrical portion 10, so that the cylindrical rib of the second cylindrical portion 20 27 functions as a mold clamping compression rib. By applying the injection pressure for the secondary molding while clamping the mold, it is possible to improve the sink marks formed on the end face in the axial direction of the primary molded product. For example, an effect of improving sink marks formed on the end surface of the first tubular portion 10 opposite to the second tubular portion 20 can be expected. Finally, in the mold release step ST4, the mold for secondary molding is opened to release the molded resin member 1 from the mold.

(Main functions and effects of the first embodiment)
As described above, in the method for manufacturing the molded resin member 1 of Embodiment 1, first, the primary molding step ST1 for molding the first cylindrical portion 10 and the second cylindrical portion 20 is performed. Next, a secondary molding preparatory step ST2 is performed. In the secondary molding preparation step ST2, the first mold C10 that holds the first tubular portion 10 and the second mold C20 that holds the second tubular portion 20 are placed in the axial direction of the first tubular portion 10 and the second tubular portion 20. By clamping the molds, one end of the second cylindrical portion 20 is fitted inside the first cylindrical portion 10 to be coaxially coupled, and a secondary molding metal having a first mold C10 and a second mold C20 is provided. A secondary molding cavity C is formed in the mold. The secondary molding cavity C includes a front end surface 11 that is an end surface of the first cylindrical portion 10, a side surface 25 and a bottom surface 26 of a second annular recess 24 provided on the outer peripheral surface of the second cylindrical portion 20, and a side surface 25. It is constituted by die faces S that are diametrically opposed. Subsequently, a secondary molding step ST3 is performed in which a molding material is injected into the secondary molding cavity C to mold the joining resin portion 7 . As a result, the front end surface 11 of the first cylindrical portion 10 and the side surface 25 and the bottom surface 26 of the second cylindrical portion 20 are bonded via the bonding resin portion 7 . In the secondary forming preparation step ST2, the end portion of the one side L1 of the second tubular portion 20 is fitted inside the first annular recessed portion 12 recessed in the axial direction from the tip surface 11 of the first tubular portion 10 . As a result, the bottom surface 14 of the first annular recess 12 and the end surface of the second tubular portion 20 , which is the annular groove, are formed on the inner peripheral surface of the through hole 2 extending in the axial direction inside the first tubular portion 10 and the second tubular portion 20 . An annular groove 3 which is an axial clearance with the surface 22 is formed.

Further, as described above, the resin molded member 1 of Embodiment 1 includes the first tubular portion 10 and the second tubular portion whose one end is fitted inside the first tubular portion 10 and extends coaxially with the first tubular portion 10 . a portion 20; An annular groove 3, which is an undercut portion recessed toward the outer circumference, opens in the inner peripheral surface of the through hole 2 extending in the axial direction inside the first tubular portion 10 and the second tubular portion 20. As shown in FIG. The annular groove 3 (undercut portion) is fitted to the bottom surface 14 of the first annular recess 12 recessed from the inner peripheral edge of the distal end surface 11 of the first tubular portion 10 toward the other side L2 in the axial direction, and the first annular recess 12. This is the gap in the axial direction with the annular surface 22 that is the end surface of the second cylindrical portion 20 . On the outer peripheral side of the second tubular portion 20, a recess formed by the tip surface 11 of the first tubular portion 10 and the side surface 25 and the bottom surface 26 of the second annular recessed portion 24 provided on the outer peripheral surface of the second tubular portion 20. A groove 6 extends in the circumferential direction. A bonding resin portion 7 for bonding the first cylindrical portion 10 and the second cylindrical portion 20 is arranged in the concave groove 6 .

In the first embodiment, the first cylindrical portion, which is a primary molded product, is formed so that the dividing line connecting the groove 6 and the annular groove 3 has the shape of the end surfaces of the first cylindrical portion 10 and the second cylindrical portion 20 . Since the shapes of 10 and the second cylindrical portion 20 are designed, it is possible to manufacture a primary molded product with no working marks or parting lines on the inner peripheral surface. Therefore, if the resin molded member 1 is manufactured by joining these by secondary molding, the annular groove 3 (undercut portion) will not be formed with working marks or parting lines. Therefore, when the sealing material 4 such as an O-ring is arranged in the annular groove 3, the adhesion of the sealing material 4 can be suppressed from being lowered.

Further, in Embodiment 1, since the concave groove 6 is formed at the position of the dividing line of the primary molded product, the primary molded product is formed through the bonding resin portion 7 formed in the concave groove 6 by secondary molding. products can be joined. Further, the concave groove 6 is formed at a position shifted from the position where the primary molded products are butted by the insertion length of the second cylindrical portion 20 into the first cylindrical portion 10 . Therefore, since no injection pressure is applied to the part (parting surface) where the primary molded products are butted together, there is little possibility that the molding material will enter inside from the parting surface, and there will be little possibility that resin burrs will form. Further, since the annular groove 3 (undercut portion) is formed by the tip portion of the second cylindrical portion 20 inserted inside the first cylindrical portion 10, it is formed at a position shifted in the axial direction from the groove 6. . Therefore, the position where the injection pressure and heat of the secondary molding are applied is shifted from the undercut part, so the deformation of the undercut part and the parts placed in the undercut part due to the injection pressure and heat are suppressed. can.

In Embodiment 1, the concave groove 6 is arranged at a position that does not overlap with the annular groove 3 (undercut portion) when viewed in the radial direction. Thus, if the positions of the recessed groove 6 and the annular groove 3 are completely shifted, the injection pressure and heat of the secondary molding are not applied to the annular groove 3, so the provision of the annular groove 3 reduces the wall thickness. Deformation of the bent portion and deformation of the parts arranged in the annular groove 3 can be eliminated. For example, deformation of the sealing material 4 can be eliminated, and deterioration of the degree of adhesion of the sealing material 4 can be suppressed.

In Embodiment 1, the undercut formed on the inner peripheral surface of the through hole 2 is the annular groove 3 extending in the circumferential direction. The annular groove 3 is an arrangement space for the sealing material 4 interposed between the shaft member 100 and the annular groove 3 . By doing so, the seal material 4 can be continuously incorporated in the inner peripheral surface of the through hole 2 over the entire circumference. Therefore, in the resin molded member 1, the sealing material 4 can ensure the airtightness of the portion through which the shaft member 100 is passed, and it is possible to suppress leakage and intrusion of gas and liquid.

In Embodiment 1, the first cylindrical portion 10 includes an annular stepped surface 17 (abutting surface) that abuts on the distal end surface 21 of the second cylindrical portion 20 in the axial direction. By aligning the end faces of the primary molded products and positioning them in this manner, the dimensional accuracy of the opening height of the annular groove 3 can be improved.

In the first embodiment, in the secondary molding preparation step ST2, the first cylindrical portion 10 and the second cylindrical portion 20 are arranged coaxially by arranging the mold pins C30 inside the first cylindrical portion 10 and the second cylindrical portion 20. to position. Therefore, the degree of coaxiality between the first cylindrical portion 10 and the second cylindrical portion 20 can be increased. In addition, since the secondary molding cavity C is arranged at a position that does not overlap with the annular groove 3 when viewed from the radial direction, and the part to which the injection pressure of the secondary molding is applied is supported from the inside by the mold pin C30, The injection pressure for secondary molding can be received by the mold pin C30. Therefore, it is possible to avoid deformation of the part to which the injection pressure of the secondary molding is applied.

In the first embodiment, in the secondary molding preparation step ST2, the sealing material 4 is placed inside the first annular recess 12, and then the end of the second tubular portion 20 is fitted into the first annular recess 12. As shown in FIG. Therefore, the sealing member 4 can be easily incorporated into the annular groove 3. Further, the structure is such that the sealing material 4 is less likely to drop out of the annular groove 3 .

(Embodiment 2)
FIG. 4 is a cross-sectional view of a resin molded member 1A of Embodiment 2. FIG. The resin-molded member 1A has two annular grooves 3A, which are undercut portions, on the inner peripheral surface of the through-hole 2 and are spaced apart in the axial direction. A sealing material 4 such as an O-ring is held in the two annular grooves 3A. The resin molded member 1 of Embodiment 1 has a single-seal structure in which the sealing material 4 is arranged at one place on the inner peripheral surface of the through hole 2, whereas the resin molded member 1A of Embodiment 2 has two seals. A double seal structure in which the sealing material 4 is arranged can be employed.

The resin molded member 1A includes a first tubular portion 10A, a second tubular portion 20A, and a third tubular portion 30A extending in the axial direction. The resin-molded member 1A is obtained by joining a plurality of primary molded products (first tubular portion 10A, second tubular portion 20A, and third tubular portion 30A) by secondary molding. The resin molded member 1 includes a first connecting portion 5A1 formed by fitting the end portion of the second cylindrical portion 20A on the one side L1 to the inside of the end portion on the other side L2 of the first cylindrical portion 10A, and the third cylindrical portion. A second coupling portion 5A2 is provided in which the end portion of the other side L2 of the second tubular portion 20A is fitted inside the end portion of the one side L1 of the tube 30A.

The resin molded member 1A is provided with annular grooves 3A at two locations inside the first coupling portion 5A1 and the second coupling portion 5A2. As shown in the partially enlarged view of FIG. 4, the first cylindrical portion 10A includes a first annular recess 12A recessed toward the one side L1 on the inner peripheral side of the distal end surface 11A of the other side L2. The end portion of the one side L1 of the second tubular portion 20A is fitted to the . The inner peripheral surface 13A of the first annular recess 12A includes a small-diameter cylindrical surface 15A extending in the axial direction from the bottom surface 14A of the first annular recess 12A, a large-diameter cylindrical surface 16A larger than the small-diameter cylindrical surface 15A, and a small-diameter cylindrical surface 15A. It has an annular stepped surface 17A connecting the large diameter cylindrical surface 16A. 20 A of 2nd cylinder parts are inserted in 12 A of 1st annular recessed parts to the position where the outer peripheral part of 21 A of front end surfaces of the one side L1 butts|abuts 17 A of annular step surfaces. Therefore, the first cylindrical portion 10A has an annular stepped surface 17A (first contact surface) that axially contacts the distal end surface 21A of the second cylindrical portion 20A. One of the two annular grooves 3A is a location where the inner peripheral portion of the tip surface 21A on the one side L1 of the second tubular portion 20A and the bottom surface 14A of the first annular recessed portion 12A face each other with a gap in the axial direction. It is a recess that can be made at

Similarly, the third cylindrical portion 30A includes a second annular recess 32A that is recessed from the distal end surface 31A of one side L1 toward the other side L2, and the end of the second cylindrical portion 20A on the other side L2 is provided inside the second annular recess 32A. parts are mated. The inner peripheral surface 33A of the second annular recess 32A includes a small-diameter cylindrical surface 35A extending in the axial direction from the bottom surface 34A of the second annular recess 32A, a large-diameter cylindrical surface 36A larger than the small-diameter cylindrical surface 35A, and a small-diameter cylindrical surface 35A. It has an annular stepped surface 37A connecting the large diameter cylindrical surface 36A. The second tubular portion 20A is inserted into the second annular recessed portion 32A until the outer peripheral portion of the distal end surface 22A on the other side L2 hits the annular stepped surface 37A. Therefore, the third cylindrical portion 30A has an annular stepped surface 37A (second contact surface) that axially contacts the distal end surface 22A of the second cylindrical portion 20A. The other of the two annular grooves 3A is a location where the inner peripheral portion of the tip surface 22A of the other side L2 of the second cylindrical portion 20A and the bottom surface 34A of the second annular recess 32A face each other with a gap in the axial direction. It is a recess that can be made at

The resin-molded member 1A is provided with a concave groove 6A at one location on the outer peripheral side of the second tubular portion 20A. The three members, ie, the first tubular portion 10A, the second tubular portion 20A, and the third tubular portion 30A are joined via the joining resin portion 7A arranged in the concave groove 6A. The recessed groove 6A of the resin molded member 1A is a recess formed at a location where the end surface of the first cylindrical portion 10A and the end surface of the third cylindrical portion 30A face each other with a gap in the axial direction on the outer peripheral side of the second cylindrical portion 20A. is. The recessed groove 6A is constituted by a distal end surface 11A on the other side L2 of the first tubular portion 10A, a distal end surface 31A on the one side L1 of the third tubular portion 30A, and an outer peripheral surface 23A of the second tubular portion 20A.

(Main functions and effects of the second embodiment)
As described above, the resin molded member 1A of the second embodiment includes the first tubular portion 10A and the second tubular portion 20A whose one end fits inside the first tubular portion 10A and extends coaxially with the first tubular portion 10A. and a third tubular portion 30A that is fitted inside the other end of the second tubular portion 20A and extends coaxially with the first tubular portion 10A and the second tubular portion 20A. An annular groove 3A, which is an undercut portion recessed toward the outer circumference, opens in the inner peripheral surface of the through hole 2 extending axially inside the first tubular portion 10A, the second tubular portion 20A, and the third tubular portion 30A. ing. The annular groove 3A (undercut portion) includes a first coupling portion 5A1 in which the second tubular portion 20A is fitted inside the first tubular portion 10A, and a second tubular portion 20A in which the second tubular portion 20A is fitted inside the third tubular portion 30A. It is provided at two locations of the second connecting portion 5A2. Annular groove 3A of first coupling portion 5A1
The bottom surface 14A of the first annular recess 12A recessed from the tip surface 11A of the first tubular portion 10A toward one side L1 in the axial direction, and the one side L1 (one end L1) of the second tubular portion 20A fitted into the first annular recess 12A side) with the tip surface 21A in the axial direction. The annular groove 3A of the second coupling portion 5A2 includes a bottom surface 34A of a second annular recess 32A recessed from the tip surface 31A of the third cylindrical portion 30A toward the other side L2 in the axial direction, and a second annular groove 34A fitted into the second annular recess 32A. This is the gap in the axial direction of the tip surface 22A on the other side L2 (the other end side) of the cylindrical portion 20A. On the outer peripheral side of the second cylindrical portion 20A, a recessed groove 6A is formed by the distal end surface 11A of the first cylindrical portion 10A, the outer peripheral surface 23A of the second cylindrical portion 20A, and the distal end surface 31A of the third cylindrical portion 30A. A bonding resin portion 7A for bonding the first cylindrical portion 10A and the third cylindrical portion 30A to the second cylindrical portion 20A is arranged in the concave groove 6A.

In the resin molded member 1A of Embodiment 2, a dividing line connecting the concave groove 6A and the annular groove 3A on the one side L1 and a dividing line connecting the concave groove 6A and the annular groove 3A on the other side L2 are the first cylindrical portions. The shapes of the first cylindrical portion 10A and the third cylindrical portion 30A, which are primary molded products, are determined so as to have the end surface shapes of the first cylindrical portion 10A, the second cylindrical portion 20A, and the third cylindrical portion 30A. Therefore, as in the first embodiment, it is possible to manufacture a primary molded product with no working marks or parting lines on the inner peripheral surface, and by joining these by secondary molding, the through hole 2 and the annular groove 3A (undercut portion ) can produce a resin molded member 1A with no working marks or parting lines. Therefore, when the sealing material 4 such as an O-ring is arranged in the annular groove 3, the degree of adhesion of the sealing material 4 can be suppressed from being lowered.

Further, the resin molded member 1A of Embodiment 2 is configured so that the groove 6A can be formed at the position of the dividing line of the primary molded product, similarly to Embodiment 1, so that the groove 6A is formed by secondary molding. The primary molded product can be joined via the joining resin portion 7A. Further, the concave groove 6A does not overlap with the annular groove 3A when viewed from the radial direction. Therefore, as in the first embodiment, when the mold pins are arranged inside the first cylindrical portion 10A, the second cylindrical portion 20A, and the third cylindrical portion 30A and the secondary molding is performed, the resin pressure of the secondary molding can be received by the mold pin. Therefore, deformation of the annular groove 3A (undercut portion) and deformation of parts such as the sealing material 4 arranged in the annular groove 3A due to the injection pressure and heat of the secondary molding are eliminated, and the degree of adhesion of the sealing material 4 is improved. Decrease can be suppressed.

Furthermore, since the resin molded member 1A of Embodiment 2 has a structure in which three primary molded products can be bonded by the bonding resin portion 7A arranged in one concave groove 6A, the mold for secondary molding is Structure can be simplified. For example, the mold for secondary molding can be provided with a mold surface that faces the outer peripheral surface 23A of the second tubular portion 20A in the radial direction. In this case, in the secondary molding preparation step, the tip surface 11A of the first cylindrical portion 10A, the outer peripheral surface 23A of the second cylindrical portion 20A, the mold surface radially facing the outer peripheral surface 23A, and the third cylindrical portion 30A A cavity for secondary molding is formed by the tip surface 31A, and a molding material can be injected into the cavity for secondary molding to mold the bonding resin portion 7A.

(Embodiment 3)
FIG. 5 is a cross-sectional view of a resin molded member 1B of Embodiment 3. FIG. The resin molded member 1B is provided with annular grooves 3B, which are undercut portions, at three locations spaced apart in the axial direction. Sealing materials 4 such as O-rings are held in the three annular grooves 3B. The resin molded member 1B of Embodiment 3 can have a triple seal structure in which seal members 4 are arranged at three positions when the shaft member is arranged in the through hole 2 .

The molded resin member 1B includes a first tubular portion 10B, a second tubular portion 20B, a third tubular portion 30B, and a fourth tubular portion 40B extending in the axial direction. The molded resin member 1B is obtained by joining a plurality of primary molded products (the first tubular portion 10B, the second tubular portion 20B, the third tubular portion 30B, and the fourth tubular portion 40B) by secondary molding. The resin molded member 1 includes a first connecting portion 5B1 in which the end portion of the second cylindrical portion 20B on the one side L1 is fitted inside the end portion on the other side L2 of the first cylindrical portion 10B, and the second cylindrical portion 20B. A second connecting portion 5B2 in which the end portion of the one side L1 of the third cylindrical portion 30B is fitted inside the end portion of the other side L2, and a second coupling portion 5B2 inside the end portion of the one side L1 of the fourth cylindrical portion 40B. A third coupling portion 5B3 is provided to which the end portion of the other side L2 of the three cylinder portion 30B is fitted.

The resin-molded member 1B has annular grooves 3B at three locations inside the first coupling portion 5B1, the second coupling portion 5B2, and the third coupling portion 5B3. The first joint portion 5B1 and the second joint portion 5B2 have the same structure as the first joint portion 5A1 of the second embodiment, and the third joint portion 5B3 has the same structure as the second joint portion 5A2 of the second embodiment. Therefore, detailed description is omitted.

The resin-molded member 1B has a recessed groove 6B1 on the outer peripheral side of the second cylindrical portion 20B, and a recessed groove 6B2 on the outer peripheral side of the third cylindrical portion 30B. Two members, the first cylindrical portion 10B and the second cylindrical portion 20B, are joined via a bonding resin portion 7B1 disposed in the groove 6B1, and via a bonding resin portion 7B2 disposed in the groove 6B2, Three members of the second tubular portion 20B, the third tubular portion 30B, and the fourth tubular portion 40B are joined. The bonding resin portions 7B1 and 7B2, as in the first and second embodiments, supply the molding material to two secondary molding cavities formed by the mold surface of the secondary molding mold and the concave grooves 6B1 and 6B2. Can be molded by injection.

(Main functions and effects of the third embodiment)
In the resin molded member 1B of Embodiment 3, as in Embodiment 1, the primary molded product is divided at the position of the annular groove 3B (undercut portion), and the primary molded product is free from machining marks and parting lines. Since it can be manufactured by the manufacturing method, it is possible to manufacture the resin molded member 1B that does not have working marks or parting lines in the annular groove 3B (undercut portion). Therefore, when the sealing material 4 such as an O-ring is arranged in the annular groove 3, the degree of adhesion of the sealing material 4 can be suppressed from being lowered.

Further, as in the first embodiment, since the concave grooves 6B1 and 6B2 are formed at the positions of the dividing lines of the primary molded product, the bonding resin portion 7B1 formed into the concave grooves 6B1 and 6B2 by secondary molding. , 7B2. Further, the concave grooves 6B1 and 6B2 do not overlap the annular groove 3B when viewed from the radial direction. Therefore, as in the first embodiment, when secondary molding is performed by arranging mold pins inside the first cylindrical portion 10B, the second cylindrical portion 20B, the third cylindrical portion 30B, and the fourth cylindrical portion 40B, The mold pin can receive the resin pressure of the secondary molding. Therefore, deformation of the annular groove 3B (undercut portion) and deformation of parts such as the sealing material 4 arranged in the annular groove 3B due to the injection pressure and heat of the secondary molding are eliminated, and the degree of adhesion of the sealing material 4 is improved. Decrease can be suppressed.

(Embodiment 4)
FIG. 6 is a cross-sectional view of a resin molded member 1C of Embodiment 4. FIG. Similar to the third embodiment, the resin molded member 1C has annular grooves 3C, which are undercut portions, at three locations separated in the axial direction, and has a triple seal structure in which seal members 4 are arranged at three locations.

The resin molded member 1C is obtained by joining a plurality of primary molded products (first tubular portion 10C, second tubular portion 20C, third tubular portion 30C, and fourth tubular portion 40C) by secondary molding. The resin molded member 1 includes a first connecting portion 5C1 and a second cylindrical portion 20C, which are formed by fitting the end portion of the second cylindrical portion 20C on the one side L1 to the inner side of the end portion on the other side L2 of the first cylindrical portion 10C. A second coupling portion 5C2 in which the end portion of the one side L1 of the third cylindrical portion 30C is fitted inside the end portion of the other side L2, and a second coupling portion 5C2 inside the end portion of the one side L1 of the fourth cylindrical portion 40C. A third coupling portion 5C3 is provided to which the end portion of the other side L2 of the third cylindrical portion 30C is fitted.

The resin molded member 1C is provided with annular grooves 3C at three locations inside the first coupling portion 5C1, the second coupling portion 5C2, and the third coupling portion 5C3. As shown in the partially enlarged view of FIG. 6, the annular groove 3C of the first coupling portion 5C1 is a first groove recessed toward the one side L1 in the axial direction on the inner peripheral side of the distal end surface 11C of the other side L2 of the first cylindrical portion 10C. It is the gap in the axial direction between the bottom surface 14C of the annular recess 12C and the tip surface 21C on the one side L1 of the second cylindrical portion 20C fitted in the first annular recess 12C.

The annular groove 3C of the first coupling portion 5C1 is a groove having a pair of annular surfaces (tip surface 21C and bottom surface 14C) facing each other in the axial direction and an inner peripheral surface 13C connecting the outer peripheral edges of the pair of annular surfaces. . A pair of annular surfaces (tip surface 21C and bottom surface 14C) have radially inner ends formed with retaining projections 81 protruding in the axial direction. Therefore, the opening height of the annular groove 3C on the inner peripheral surface of the through hole 2 is narrowed by the protrusion height of the retainer protrusion 81 .

The tip portion of the second cylindrical portion 20C is fitted inside the inner peripheral surface 13C of the first annular recess 12C. 20 C of 2nd cylinder parts are provided with the 2nd annular recessed part 24C which dents the outer peripheral side of the front end surface 21C of the one side L1 to the other side L2. The tip portion of the first tubular portion 10C is fitted to the outer peripheral side of the side surface 25C of the second annular recessed portion 24C. The first cylindrical portion 10C and the second cylindrical portion 20C are positioned in the axial direction by abutting the tip surface 11C of the first cylindrical portion 10C against the bottom surface 26C of the second annular recess 24C.

An annular recess 15C recessed toward the one side L1 from the outer peripheral edge of the tip end surface 11C is formed on the end surface of the first cylindrical portion 10C on the other side L2. Therefore, the bottom surface 17C of the recess 15C and the bottom surface 26C of the second annular recess 24C face each other with a gap in the axial direction. The concave groove 6C1 is a groove formed by the bottom surface 17C and the side surface 16C of the concave portion 15C and the bottom surface 26C of the second annular concave portion 24C in the second tubular portion 20C.

The second coupling portion 5C2 and the third coupling portion 5C3 of the resin molded member 1C are the same as the first coupling portion 5A1 and the second coupling portion 5A1 of the second embodiment, except that the retaining protrusion 81 is formed at the edge of the annular groove 3C. It has the same structure as the connecting portion 5A2, and the second connecting portion 5B2 and the third connecting portion 5B3 of the third embodiment. Therefore, detailed description is omitted.

The resin molded member 1C includes a groove 6C1 on the outer peripheral side of the second tubular portion 20C and a groove 6C2 on the outer peripheral side of the third tubular portion 30C. Two members, ie, the first tubular portion 10C and the second tubular portion 20C are joined via a joining resin portion 7C1 arranged in the concave groove 6C1. Also, the three members of the second tubular portion 20C, the third tubular portion 30C, and the fourth tubular portion 40C are joined via the joining resin portion 7C2 arranged in the concave groove 6C2. The bonding resin portions 7C1 and 7C2 inject the molding material into two secondary molding cavities formed by the mold surface of the secondary molding mold and the concave grooves 6C1 and 6C2, as in the third embodiment. can be molded by

(Main functions and effects of the fourth embodiment)
The resin molded member 1C of Embodiment 4 can be manufactured by a manufacturing method that does not cause working marks or parting lines in the primary molded product, as in Embodiment 1. Therefore, the annular groove 3C (undercut portion) has working marks or parting lines. The resin molded member 1C can be manufactured without lines. Therefore, when arranging the sealing material 4 such as an O-ring in the annular groove 3C, it is possible to suppress a decrease in the degree of adhesion of the sealing material 4 .

Further, as in the first embodiment, since the concave grooves 6C1 and 6C2 are formed at the positions of the dividing lines of the primary molded product, the bonding resin portion 7C1 formed into the concave grooves 6C1 and 6C2 by secondary molding is formed. , 7C2. Further, the concave grooves 6C1 and 6C2 do not overlap the annular groove 3C (undercut portion) when viewed from the radial direction. Therefore, as in the first embodiment, when secondary molding is performed by arranging mold pins inside the first cylindrical portion 10C, the second cylindrical portion 20C, the third cylindrical portion 30C, and the fourth cylindrical portion 40C, The mold pin can receive the resin pressure of the secondary molding. Therefore, deformation of the annular groove 3C due to the injection pressure and heat of the secondary molding and deformation of parts such as the sealing material 4 arranged in the annular groove 3C can be eliminated, and a decrease in the degree of adhesion of the sealing material 4 can be suppressed.

Furthermore, the resin molded member 1C of the fourth embodiment is axially aligned along the radially inner edges of the pair of annular surfaces forming the annular groove 3C (that is, the opening edge of the annular groove 3C on the inner peripheral surface of the through hole 2). A protruding retaining projection 81 is formed. Therefore, it is possible to prevent parts such as the sealing material 4 mounted in the annular groove 3C from coming off. In addition, the retainer protrusion 81 may be provided on at least one of the pair of annular surfaces forming the annular groove 3C. For example, in the case of the annular groove 3C of the first coupling portion 5C1, the retaining protrusion 81 is provided on the inner peripheral edge of either the tip surface 21C or the bottom surface 14C, and the retaining protrusion 81 is not provided on the other inner peripheral edge. It may be a structure. Further, the retaining projections 81 may not be provided on the entire circumference, and a plurality of retaining projections 81 may be arranged circumferentially at predetermined intervals.

(Embodiment 5)
FIG. 7 is a cross-sectional view of a resin molded member 1D of Embodiment 5. FIG. Similar to Embodiments 3 and 4, the resin molded member 1D has annular grooves 3D, which are undercut portions, at three locations apart from each other in the axial direction, and has a triple seal structure in which seal members 4 are arranged at three locations. .

The molded resin member 1D is obtained by joining a plurality of primary molded products (first tubular portion 10D, second tubular portion 20D, third tubular portion 30D, and fourth tubular portion 40D) by secondary molding. The resin molded member 1D includes a first connecting portion 5D1 formed by fitting an end portion of one side L1 of the second cylindrical portion 20D to an inner side of an end portion of the other side L2 of the first cylindrical portion 10D, and a second cylindrical portion 20D. A second connecting portion 5D2 in which the end portion of the one side L1 of the third cylindrical portion 30D is fitted inside the end portion of the other side L2, and a second connecting portion 5D2 inside the end portion of the one side L1 of the fourth cylindrical portion 40D. A third connecting portion 5D3 is provided to which the end portion of the other side L2 of the three cylindrical portion 30D is fitted.

The resin-molded member 1D has annular grooves 3D at three locations inside the first coupling portion 5D1, the second coupling portion 5D2, and the third coupling portion 5D3. The annular groove 3D is a groove having a pair of annular surfaces facing each other in the axial direction and an inner peripheral surface connecting the outer peripheral edges of the pair of annular surfaces. In the fifth embodiment, the pair of opposing annular surfaces are inclined surfaces 82 that are inclined in a direction in which the distance between the opposing surfaces decreases toward the inner peripheral side. The fifth embodiment has the same structure as that of the fourth embodiment, except that an inclined surface 82 is provided instead of the retaining projection 81 .

(Main actions and effects of Embodiment 5)
As in Embodiment 1, the resin molded member 1D of Embodiment 5 can be manufactured by a manufacturing method that does not leave working marks or parting lines on the primary molded product. A resin-molded member 1D without a line can be manufactured. Therefore, when the sealing material 4 such as an O-ring is arranged in the annular groove 3D, it is possible to suppress a decrease in the degree of adhesion of the sealing material 4 .

Further, as in the first embodiment, since the grooves 6D1 and 6D2 are formed at the positions of the division lines of the primary molded product, the bonding resin portion 7D1 formed into the grooves 6D1 and 6D2 by secondary molding is formed. , 7D2. Further, the concave grooves 6D1 and 6D2 are arranged at positions that do not overlap with the annular groove 3D when viewed from the radial direction. Therefore, as in the first embodiment, when secondary molding is performed by arranging mold pins inside the first cylindrical portion 10D, the second cylindrical portion 20D, the third cylindrical portion 30D, and the fourth cylindrical portion 40D, The mold pin can receive the resin pressure of the secondary molding. Therefore, since deformation due to injection pressure and heat in secondary molding can be avoided, deformation of the annular groove 3D and deformation of the parts (sealing material 4) arranged in the annular groove 3D can be eliminated. A decrease in adhesion can be suppressed.

Furthermore, in the resin molded member 1D of Embodiment 5, the pair of annular surfaces forming the annular groove 3D are provided with inclined surfaces 82, and the opening height of the annular groove 3D is shaped such that the opening height of the annular groove 3D becomes narrower toward the inner peripheral side. . Therefore, it is possible to prevent parts such as the sealing material 4 mounted in the annular groove 3D from coming off. In the embodiment shown in FIG. 7, the pair of annular surfaces are entirely inclined surfaces, but at least a part of the pair of annular surfaces may be inclined surfaces. For example, only the inner peripheral portions of the pair of annular surfaces may be inclined surfaces. Also, only one of the pair of annular surfaces may be an inclined surface.

(Embodiment 6)
8A and 8B are cross-sectional views of a resin molded member 1E of Embodiment 6, FIG. 8A is a cross-sectional view cut along a plane including the central axis L, and FIG. It is sectional drawing cut|disconnected by A position. In Embodiment 1-5, the annular groove is provided as the undercut portion, and the sealing material 4 is arranged in the annular groove. A bearing member 9 is arranged. The bearing member 9 is a bearing that includes a rolling element 91 and a rolling element holding portion 92 that holds the rolling element 91 so that it can roll.

The resin-molded member 1E includes a connecting portion 5E in which the end portion of the second cylindrical portion 20E on the one side L1 is fitted inside the end portion on the other side L2 of the first cylindrical portion 10E extending in the axial direction. The first cylindrical portion 10E includes a first annular recessed portion 12E recessed toward the one side L1 from the inner peripheral side of the distal end surface 11E on the other side L2. The annular groove 3E is an axial gap between the bottom surface 14E of the first annular recess 12E and the tip surface 21E of the second cylindrical portion 20E fitted inside the first annular recess 12E. Further, the molded resin member 1E includes a recessed groove 6E formed on the outer peripheral surface of the coupling portion 5E in the same manner as the recessed groove 6C1 of the fourth embodiment. A bonding resin portion 7E is arranged in the concave groove 6E.

The rolling elements 91 are spherical bodies made of metal, ceramic, graphite, or the like. A cylindrical roller can also be used as the rolling element 91 . The rolling element holding portions 92 are partition walls arranged radially in the annular groove 3E. In the example shown in FIG. 8, one rolling element 91 is held between partition walls (rolling element holding portions 92) adjacent in the circumferential direction. Therefore, the rolling elements 91 are held side by side at regular intervals in the circumferential direction on the inner peripheral surface of the through hole 2 , and the rolling elements 91 slide on the surface of the shaft member arranged in the through hole 2 .

The rolling element holding portion 92 is formed integrally with the inner surface of the annular groove 3E. In the form shown in FIG. 8, the rolling element holding portion 92 (partition wall) protrudes from the inner peripheral surface 13E of the first annular recessed portion 12E to the inner peripheral side. A structure in which the rolling element holding portion 92 protrudes from the bottom surface 14E of the first annular concave portion 12E or the tip end surface 21E of the second cylindrical portion 20E may be employed. Alternatively, the rolling element holding portion 92 may be a separate member from the first tubular portion 10E and the first tubular portion 10E.

(Main functions and effects of Embodiment 6)
As in Embodiment 1, the resin molded member 1E of Embodiment 6 can be manufactured by a manufacturing method that does not leave working marks or parting lines on the primary molded product. A resin molded member 1B without a line can be manufactured. By providing the annular groove 3</b>E, it is possible to secure a space for incorporating the bearing member 9 continuously over the entire circumference of the inner peripheral surface of the through hole 2 . Therefore, the bearing member 9 can enhance the slidability of the shaft member.

Further, as in the first embodiment, since the groove 6E is formed at the position of the dividing line of the primary molded product, the primary molding is formed through the bonding resin portion 7E formed in the groove 6E by secondary molding. Molded products can be joined. Further, the concave groove 6E is arranged at a position not overlapping with the annular groove 3E when viewed from the radial direction. Therefore, as in the first embodiment, since the injection pressure and heat of the secondary molding are not applied to the position of the annular groove 3E, deformation of the annular groove 3E and deterioration of the part (bearing member 9) arranged in the annular groove 3E deformation can be avoided.

In the bearing member 9 of Embodiment 6, the rolling element holding portion 92 is formed integrally with the first cylindrical portion 10E. Therefore, before fitting the second cylindrical portion 20E to the first cylindrical portion 10E, the work of dropping the rolling elements 91 between the partition walls (rolling element holding portions 92) is performed, and then the first cylindrical portion 10E and the second cylindrical portion 10E are separated from each other. The bearing can be incorporated into the annular groove 3 only by fitting the cylindrical portion 20E. Therefore, it is possible to construct a bearing that has a small number of parts and is easy to assemble.

Note that the bearing member arranged in the annular groove is not limited to the form shown in FIG. For example, an oilless bush may be arranged as the bearing member. A bearing in which rolling elements such as spheres are arranged between the inner ring and the outer ring can also be used. In this case, the shaft member may be provided with a press-fitting portion that is press-fitted into the inner ring of the bearing, and the inner ring and the shaft member can be coupled by press-fitting.

(Modification of bearing member)
FIG. 9 is a cross-sectional view of the resin molded member 1F cut at the position of the bearing member 9F of Modification 1. As shown in FIG. A resin-molded member 1F shown in FIG. 9 has an annular groove 3F formed on the inner circumference of a portion where a first tubular portion 10F and a second tubular portion (not shown) are joined. The resin molded member 1F has the same configuration as the resin molded member 1E of Embodiment 6, except for the configuration of the bearing member 9F arranged in the annular groove 3F.

As shown in FIG. 9, the bearing member 9F of Modification 1 is a bearing provided with a rolling element 91F and a rolling element holding portion 92F arranged in the annular groove 3F. A bearing member 9F of Modification 1 includes a partition wall having a surface curved in an R shape as a rolling element holding portion 92F. The rolling element holding portions 92F (partition walls) protrude radially inward from the inner peripheral surface 13F forming the annular groove 3G, and are arranged radially at regular intervals in the circumferential direction. Between the rolling element holding portions 92F (partition walls) adjacent in the circumferential direction, one rolling element 91F is held in a rollable state. When the annular groove 3F is viewed from the inner peripheral side, the rolling elements 91F are exposed to the inner peripheral side from the openings between the rolling element holding portions 92F (partition walls) adjacent in the circumferential direction.

As shown in the partially enlarged view of FIG. 9, a surface 921 on one side in the circumferential direction and a surface 922 on the other side in the circumferential direction of the rolling element holding portion 92F (partition wall) of Modification 1 are the outer peripheral surfaces of the rolling elements 91F. It is curved in a shape that follows the In the example shown in FIG. 9, the rolling element 91F is spherical or columnar. Therefore, a surface 921 on one side in the circumferential direction and a surface 922 on the other side in the circumferential direction of the rolling element holding portion 92F (partition wall) are arc-shaped curved surfaces.

FIG. 10 is a cross-sectional view of a resin molded member 1G cut at the position of the rolling element holding portion 93 of Modification 2. As shown in FIG. A resin-molded member 1G shown in FIG. 10 has an annular groove 3G formed on the inner periphery of a portion where a first tubular portion 10G and a second tubular portion (not shown) are joined. The resin molded member 1G has the same configuration as the resin molded member 1E of Embodiment 6, except for the configuration of the bearing member 9G arranged in the annular groove 3G.

As shown in FIG. 10, a bearing member 9G of Modification 1 is a bearing provided with a rolling element 91G and a rolling element holding portion 92G arranged in an annular groove 3G. A bearing member 9G of Modification 2 includes, as a rolling element holding portion 92G, a partition wall 93 whose surface is curved in an R shape, and ribs 94 that protrude from the inner peripheral end of the partition wall 93 to both sides in the circumferential direction. The partition walls 93 protrude radially inward from the inner peripheral surface 13G forming the annular groove 3G, and are radially arranged at regular intervals in the circumferential direction. Between the partition walls 93 adjacent in the circumferential direction, one rolling element 91G is held in a rollable state. The rib 94 extends in an arc shape along the inner peripheral surface of the resin molded member 1G. When the annular groove 3G is viewed from the inner peripheral side, the rolling elements 91G are exposed to the inner peripheral side from the openings between the ribs 94 adjacent in the circumferential direction.

As shown in the partially enlarged view of FIG. 10 , the rolling element holding portion 92G of Modification 2 has a surface 931 on one side in the circumferential direction of the partition wall 93 and a surface 932 on the other side in the circumferential direction of the partition wall 93 as in the case of Modification 1. is curved along the outer peripheral surface of the rolling element 91G. In the example shown in FIG. 10, the rolling element 91G is spherical or columnar. Therefore, a surface 931 on one side in the circumferential direction of the partition wall 93 and a surface 932 on the other side in the circumferential direction are arc-shaped curved surfaces.

(Main functions and effects of Modifications 1 and 2)
As described above, the surfaces of the rolling element holding portions 92F and 92G of Modifications 1 and 2 on both sides in the circumferential direction are arranged between the rolling element holding portions 92F and 92G (partition walls) adjacent in the circumferential direction. It is curved along the outer peripheral surfaces of the rolling elements 91F and 91G. As a result, it is possible to reduce the circumferential width of the openings exposing the rolling elements 91F, 91G on the inner peripheral surfaces of the cylindrical resin molded members 1F, 1G. It is possible to hold the rolling elements 91F and 91G stably so as not to fall off. In addition, since the rolling element holding portion 92G of Modification Example 2 includes ribs extending from the inner peripheral end of the partition wall 93 to both sides in the circumferential direction, the opening exposing the rolling element 91G extends in the circumferential direction. The opening width can be made even smaller. Therefore, it is possible to more reliably prevent the rolling elements 91G from coming off.

In addition, when providing a partition as a rolling element holding|maintenance part, the surface of a partition may be the curved surface bent in the shape along the outer peripheral surface of a rolling element. In addition, the rolling element holding portion 92G of Modification 2 has curved surfaces 931 and 932 of the partition wall 93 and has ribs 94 provided at the inner peripheral end portions. A rib projecting in the circumferential direction may be provided at the end portion on the inner peripheral side of the rolling element holding portion 92 (partition wall) having a uniform thickness.

Reference Signs List 1, 1A, 1B, 1C, 1D, 1E, 1F, 1G... Resin molded member 2... Through hole 3, 3A, 3B, 3C, 3D, 3E, 3F, 3G... Annular groove 4... Seal material 5 , 5E... coupling portion, 5A1, 5B1, 5C1, 5D1... first coupling portion, 5A2, 5B2, 5C2, 5D2... second coupling portion, 5B3, 5C3, 5D3... third coupling portion, 6, 6A, 6B1, 6B2 , 6C1, 6C2, 6D1, 6D2, 6E... concave grooves, 7, 7A, 7B1, 7B2, 7C1, 7C2, 7D1, 7D2, 7E... bonding resin portions, 9, 9F, 9G... bearing members, 10, 10A, 10B, 10C, 10D, 10E, 10F, 10G... first cylindrical portion, 11, 11A, 11C, 11E... tip end face, 12, 12A, 12C, 12E... first annular concave portion, 13, 13A, 13C, 13E, 13F , 13G... inner peripheral surface, 14, 14A, 14C, 14E... bottom surface, 15, 15A... small diameter cylindrical surface, 15C... concave portion, 16, 16A... large diameter cylindrical surface, 16C... side surface, 17, 17A... annular stepped surface, 17C...bottom surface 18...peripheral surface 19...cylindrical rib 20, 20A, 20B, 20C, 20D, 20E...second cylindrical portion 21, 21A, 21C, 21E...tip surface 22...annular surface 22A... Tip surface 23 Cylindrical surface 23A Peripheral surface 24, 24C Second annular concave portion 25, 25C Side surface 26 Bottom surface 27 Cylindrical rib 30A, 30B, 30C, 30D Third cylindrical portion , 31A... Tip end face 32A... Second annular concave part 33A... Inner peripheral surface 34A... Bottom surface 35A... Small diameter cylindrical surface 36A... Large diameter cylindrical surface 37A... Annular stepped surface 40B, 40C, 40D... Fourth Cylindrical portion 81 Retaining convex portion 82 Inclined surface 91, 91F, 91G Rolling element 92, 92F, 92G Rolling element holding portion 93 Partition wall 94 Rib 100 Shaft member 921, 931...Surface on one side in the circumferential direction, 922, 932...Surface on the other side in the circumferential direction, C...Secondary molding cavity, C10...First mold, C11...Core mold, C20...Second mold, C21...Core Mold, C30... second mold pin, L... central axis, L1... one side in axial direction, L2... other side in axial direction, S... mold surface

Claims (22)

A resin molded member provided with a through hole in which a shaft member is arranged,
a first cylindrical portion; and a second cylindrical portion having one end fitted inside the first cylindrical portion and extending coaxially with the first cylindrical portion;
An undercut portion recessed toward the outer periphery opens in the inner peripheral surface of the through hole extending in the axial direction inside the first tubular portion and the second tubular portion,
The undercut portion is a gap in the axial direction between a bottom surface of a first annular recess recessed in the axial direction from an end surface of the first tubular portion and an end surface of the second tubular portion fitted in the first annular recess. and
A concave groove formed by the end surface of the first cylindrical portion and the second cylindrical portion extends in the circumferential direction on the outer peripheral side of the second cylindrical portion,
A molded resin member, wherein a bonding resin portion for bonding the first cylindrical portion and the second cylindrical portion is disposed in the concave groove. A resin molded member provided with a through hole in which a shaft member is arranged,
a first tubular portion, a second tubular portion having one end fitted inside the first tubular portion and extending coaxially with the first tubular portion, and a second tubular portion having the other end fitted inside the second tubular portion. a third cylindrical portion extending coaxially with the first cylindrical portion and the second cylindrical portion;
An undercut portion recessed toward the outer circumference opens in the inner peripheral surface of the through hole extending in the axial direction inside the first tubular portion, the second tubular portion, and the third tubular portion,
The undercut portion includes a first coupling portion in which the second tubular portion is fitted inside the first tubular portion, and a second coupling portion in which the second tubular portion is fitted inside the third tubular portion. It is provided in two places of the part,
The undercut portion provided in the first coupling portion includes a bottom surface of a first annular recess recessed from the end surface of the first tubular portion toward one side in the axial direction, and the second annular recess fitted into the first annular recess. A gap in the axial direction between the end surface of the cylindrical portion on one end side,
The undercut portion provided in the second coupling portion includes a bottom surface of a second annular recess recessed from the end face of the third cylindrical portion toward the other side in the axial direction, and the second annular recess fitted into the second annular recess. A gap in the axial direction between the end surface of the cylindrical portion on the other end side,
A concave groove formed by the end surface of the first cylindrical portion, the outer peripheral surface of the second cylindrical portion, and the end surface of the third cylindrical portion extends in the circumferential direction on the outer peripheral side of the second cylindrical portion,
A molded resin member, wherein a bonding resin portion for bonding the first cylindrical portion and the third cylindrical portion to the second cylindrical portion is arranged in the concave groove. In claim 1 or 2,
The molded resin member, wherein the undercut portion is an annular groove extending in a circumferential direction. In claim 1,
A molded resin member, wherein the concave groove does not overlap with the undercut portion when viewed in a radial direction. In claim 3,
The resin-molded member, wherein the annular groove is an arrangement space for a sealing material or a bearing member interposed between the shaft member and the annular groove. In claim 3,
A molded resin member comprising an O-ring arranged in the annular groove. In claim 6,
A resin-molded member, wherein the inner surface of the annular groove is free of parting lines and processing marks. In claim 3,
A molded resin member comprising a bearing member arranged in the annular groove. In claim 8,
The bearing member is a bearing that includes a plurality of rolling elements arranged in the annular groove and a rolling element holding portion that holds the plurality of rolling elements at positions arranged at predetermined intervals in a circumferential direction. resin molded member. In claim 9,
The rolling element holding portion includes partition walls arranged radially in the annular groove,
The molded resin member, wherein the partition wall is formed integrally with the inner surface of the annular groove. In claim 10,
The molded resin member, wherein the surface of the partition wall is curved or bent in a shape along the outer peripheral surface of the rolling element arranged between the partition walls adjacent in the circumferential direction. In claim 10,
The resin-molded member, wherein the rolling element holding portion includes a rib extending from an inner peripheral side end portion of the partition wall to both sides in a circumferential direction. In claim 3,
The annular groove comprises a pair of annular surfaces facing each other in the axial direction,
A molded resin member, comprising: a retainer projection projecting in the axial direction from an inner peripheral edge of at least one of the pair of annular surfaces. In claim 3,
The annular groove comprises a pair of annular surfaces facing each other in the axial direction,
A molded resin member, wherein at least one of the pair of annular surfaces has an inclined surface that is inclined in a direction in which a distance from the other of the pair of annular surfaces narrows toward the inner peripheral side. In claim 1,
The molded resin member, wherein the first cylindrical portion has a contact surface that contacts one end of the second cylindrical portion in the axial direction. In claim 2,
The first cylindrical portion has a first contact surface that contacts one end of the second cylindrical portion in the axial direction,
The molded resin member, wherein the third cylindrical portion has a second contact surface that contacts the other end of the second cylindrical portion in the axial direction. A method for manufacturing a resin-molded member provided with a through-hole in which a shaft member is arranged, comprising:
a primary molding step of molding the first cylindrical portion and the second cylindrical portion;
By clamping a first mold holding the first cylindrical portion and a second mold holding the second cylindrical portion in the axial direction of the first cylindrical portion and the second cylindrical portion, the first One end of the second cylindrical portion is fitted inside the cylindrical portion to be coaxially coupled, and the first cylindrical portion, the second cylindrical portion, and a secondary molding preparation step of forming a secondary molding cavity surrounded by the mold surface on the outer peripheral side of the second cylindrical portion ;
a secondary molding step of injecting a molding material into the secondary molding cavity to mold a bonding resin portion that bonds the first cylindrical portion and the second cylindrical portion;
In the secondary molding preparation step,
One end of the second cylindrical portion is fitted to the inner side of the first annular recess recessed in the axial direction from the end surface of the first cylindrical portion, and a gap between the bottom surface of the first annular recess and the end surface of the second cylindrical portion is provided. By forming the gap in the axial direction in the inner peripheral surface of the through hole extending in the axial direction inside the first cylindrical portion and the second cylindrical portion, an undercut portion recessed toward the outer peripheral side is formed in the inner peripheral surface of the through hole. A method of manufacturing a resin-molded member, characterized by: In claim 17,
A method of manufacturing a resin molded member, wherein the undercut portion is an annular groove extending in a circumferential direction. In claim 18,
In the secondary molding preparation step,
After disposing a sealing material or a bearing member inside the first annular recess, one end of the second cylindrical portion is fitted into the first annular recess, thereby inserting the sealing material or the bearing member into the annular groove. A method of manufacturing a resin molded member, characterized by holding In claim 18,
In the secondary molding preparation step,
coaxially positioning the first cylindrical portion and the second cylindrical portion by arranging mold pins inside the first cylindrical portion and the second cylindrical portion;
A method of manufacturing a resin-molded member, wherein the secondary molding cavity is formed at a position that does not overlap with the annular groove when viewed in a radial direction. In claim 17,
In the secondary molding step, a thermosetting resin as the molding material is filled into the secondary molding cavity and heated, whereby the bonding resin portion is formed into the first cylinder by a cross-linking reaction of the thermosetting resin. A method of manufacturing a resin-molded member, characterized in that the resin-molded member is joined to the part and the second tubular part. In claim 17,
In the secondary molding step, the first mold and the second mold are clamped while injecting the molding material into the secondary molding cavity.

Images