Soft member mounting structure

Abstract

To provide a mounting structure of a soft member capable of surely preventing the soft member from falling off, facilitating the mounting work of the soft member, suppressing rattling of the soft member in the axial direction, and preventing a gap in the axial direction from being formed between the soft member and a cylinder end part.SOLUTION: The tubular body includes an attachment hole, an inward protrusion, and a lower surface below the inward protrusion. The soft member includes a large-diameter portion, a small-diameter portion, an outward protrusion, and an upper surface above the outward protrusion. The soft member is inserted and attached to the mounting hole by the outward protrusion and the inward protrusion being retained and locked in the axial direction. The opening end of the mounting hole and the lower end of the large-diameter portion are in contact with each other in the axial direction, and an axial gap is provided between the upper surface and the lower surface. At least one of an upper protrusion protruding upward from the upper surface and a lower protrusion protruding downward from the lower surface is formed, and the upper protrusion and the lower protrusion are a plurality of protrusions spaced apart from each other in the circumferential direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a mounting structure for a soft member, and more particularly to a mounting structure for a soft member in which a mounting hole that opens axially upward is provided at the upper end of a cylindrical body such as a barrel or cap of a writing instrument, and a soft member is inserted into the mounting hole. [Background technology]

[0002] Patent Document 1 discloses a mounting structure for a soft member in which a mounting hole that opens axially upward is provided at the upper end of a cylindrical body and a soft member is inserted into the mounting hole, with an inward protrusion formed on the inner surface of the mounting hole and an outward protrusion formed on the outer surface of the soft member, and the outward protrusion riding over the inward protrusion from above to below.

[0003] In the mounting structure for the soft member, the soft member comprises a large-diameter portion that protrudes axially upward from the upper end of the cylindrical body, and a small-diameter portion that is integrally connected downward from the large-diameter portion and is inserted into the mounting hole. When the soft member is inserted into the mounting hole, the opening edge of the mounting hole and the lower end of the large-diameter portion abut in the axial direction, and an axial gap C is provided between the inward protrusion and the outward protrusion. The appropriate range for the axial gap C is 0.05 mm to 1.0 mm (preferably 0.1 mm to 0.5 mm).

[0004] According to this soft member mounting structure, it is possible to reliably prevent the soft member from falling off, and furthermore, it is a soft member mounting structure that makes it easy to mount the soft member. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-144991 Summary of the Invention [Problem to be solved by the invention]

[0006] According to the soft member mounting structure described in Patent Document 1, the provision of the gap C makes it possible to reliably prevent the soft member from falling off and also makes the work of mounting the soft member easier. However, there is a risk that the gap C may cause rattle in the axial direction of the soft member.

[0007] Furthermore, the base described in Patent Document 1 can prevent the large diameter portion from wobbling in the radial direction. However, since the base has an inclined surface (i.e., a conical surface) whose outer diameter gradually increases upward, a force is generated that pulls the soft member upward in the state shown in Figure 3 or Figure 6 of Patent Document 1.

[0008] As a result, the gap C shown in Figure 3 or Figure 6 of Patent Document 1 will disappear, and instead there is a risk that an axial gap will be created between the soft member and the end of the cylindrical body, which is undesirable from an appearance perspective.

[0009] The present invention has been made in light of the above findings, and its object is to provide a mounting structure for a soft member that can reliably prevent the soft member from falling off, facilitates the mounting work of the soft member, suppresses axial rattle of the soft member, and prevents an axial gap from forming between the soft member and the end of the cylindrical body. [Means for solving the problem]

[0010] The present invention provides a mounting structure for a soft member, which is formed by inserting a soft member into a cylindrical body at the end of a writing implement, the cylindrical body comprising a mounting hole that opens upward in the axial direction, an inward protrusion formed on the inner peripheral surface of the mounting hole, and a lower surface formed below the inward protrusion, the soft member comprising a large diameter portion that protrudes upward from the opening end of the mounting hole, a small diameter portion that is integrally connected downward from the large diameter portion and is inserted into the mounting hole, an outward protrusion formed on the outer peripheral surface of the small diameter portion, and an upward protrusion formed above the outward protrusion. and a surface, wherein the soft member is inserted into the mounting hole by the outward protrusion and the inward protrusion being locked in the axial direction to prevent slipping out, the opening end of the mounting hole and the lower end of the large diameter portion are abutted in the axial direction, an axial gap is provided between the upper surface and the lower surface, and at least one of an upper protrusion protruding upward from the upper surface or a lower protrusion protruding downward from the lower surface is formed, and the upper protrusion and the lower protrusion are a plurality of protrusions spaced apart in the circumferential direction.

[0011] According to the present invention, the outward projection and the inward projection each have an upper surface and a lower surface, and at least one of an upper projection that projects upward from the upper surface or a lower projection that projects downward from the lower surface is formed, and the upper projection and the lower projection are a plurality of projections spaced apart in the circumferential direction, which makes it possible to reliably prevent the soft member from falling off, and also makes the installation work of the soft member easier, suppresses axial rattle of the soft member, and prevents the formation of an axial gap between the soft member and the end of the cylindrical body.

[0012] The present invention also provides a mounting structure for a soft member, which is formed by inserting a soft member into a cylindrical body at the end of a writing implement, wherein the cylindrical body has a mounting hole opening axially upward, an inward protrusion formed on the inner peripheral surface of the mounting hole, an upper surface formed above the opening end of the mounting hole, and a wall portion protruding upward from the upper surface, the inner diameter of the wall portion being larger than the inner diameter of the opening end of the mounting hole, and the soft member has a large diameter portion protruding upward from the opening end of the mounting hole, and a small diameter portion integrally connected downward from the large diameter portion and inserted into the mounting hole, The soft member is provided with an outward protrusion formed on the outer peripheral surface of the small diameter portion and a lower surface formed below the large diameter portion, and the soft member is inserted into the mounting hole by the outward protrusion and the inward protrusion being axially engaged to prevent slipping out, an axial gap is provided between the upper surface and the lower surface, and at least one of an upper protrusion protruding upward from the upper surface or a lower protrusion protruding downward from the lower surface is formed, and the upper protrusion and the lower protrusion are a plurality of protrusions spaced apart in the circumferential direction.

[0013] According to the present invention, the connector has an upper surface formed above the opening end of the mounting hole, a lower surface formed below the large-diameter portion, and a wall portion projecting upward from the upper surface, and is provided with at least one of an upper protrusion projecting upward from the upper surface and a lower protrusion projecting downward from the lower surface, the upper protrusion and the lower protrusion being a plurality of protrusions spaced apart in the circumferential direction, which makes it possible to reliably prevent the soft member from falling off, facilitates the installation of the soft member, suppresses axial rattle of the soft member, and prevents the formation of an axial gap between the soft member and the end of the cylindrical body. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a mounting structure for a soft member that can reliably prevent the soft member from falling off, and also that facilitates the mounting work of the soft member, suppresses axial rattle of the soft member, and prevents an axial gap from occurring between the soft member and the end of the cylindrical body. [Brief explanation of the drawings]

[0015] [Figure 1]1 is an enlarged longitudinal cross-sectional view of a main part showing a state in which a soft member is inserted into a cylindrical body in a first embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view showing the cylindrical body of FIG. [Figure 3] FIG. 10 is an enlarged longitudinal cross-sectional view of a main part showing a state in which a soft member is inserted into a cylindrical body in a second embodiment of the present invention. [Figure 4] FIG. 4 is a perspective view showing the soft member of FIG. 3. [Figure 5] FIG. 11 is an enlarged longitudinal cross-sectional view of a main part showing a state in which a soft member is inserted into a cylindrical body in a third embodiment of the present invention. [Figure 6] FIG. 6 is a perspective view showing the cylindrical body of FIG. 5. [Figure 7] FIG. 10 is an enlarged longitudinal cross-sectional view of a main part showing a state in which a soft member is inserted into a cylindrical body in a fourth embodiment of the present invention. [Figure 8] FIG. 8 is a perspective view showing the soft member of FIG. 7. DETAILED DESCRIPTION OF THE INVENTION

[0016] Four embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to the following embodiments. In the mounting structure of the soft member 20 of the present embodiment, "upper" refers to the mounting hole 11 side of the cylindrical body 10, and refers to the large diameter portion 23 side of the soft member 20. On the other hand, in the present invention, "lower" refers to the opposite side of the mounting hole 11 of the cylindrical body 10, and refers to the small diameter portion 21 side of the soft member 20.

[0017] First Embodiment The mounting structure for the soft member 20 in this embodiment comprises a cylindrical body 10 having a mounting hole 11 at the upper end, and the soft member 20 inserted into the mounting hole 11 of the cylindrical body 10. Fig. 1 is an enlarged vertical cross-sectional view of a main part of the first embodiment of the present invention, showing the state in which the soft member 20 is inserted into the cylindrical body 10 at the end of the writing implement. Fig. 2 is a perspective view showing the features of the cylindrical body 10 in the first embodiment.

[0018] ·Cylinder body The cylindrical body 10 is obtained by injection molding or extrusion molding of synthetic resin (such as polypropylene, polycarbonate, ABS, etc.). The cylindrical body at the end of the writing instrument refers to, for example, the barrel of the writing instrument or a cap that is detachably attached to the nib side of the barrel.

[0019] 1, an attachment hole 11 that opens axially upward is formed in the upper end of the cylindrical body 10. If the cylindrical body 10 is a cap, the attachment hole 11 is formed on the closed end side of the cap, and if the cylindrical body 10 is a barrel, the attachment hole 11 is formed on the end opposite the nib (the tail end of the barrel).

[0020] ·Introverted process 1 or 2, an annular inward protrusion 12 is integrally formed on the inner peripheral surface of the mounting hole 11. The inward protrusion 12 has a guide portion 12a formed of an inclined surface (i.e., a conical surface) whose inner diameter gradually decreases downward. In addition, a minimum inner diameter portion 12b is formed at the lower end of the inward protrusion 12 below the guide portion 12a.

[0021] 1, a downwardly opening recess 12e is formed between the minimum inner diameter portion 12b of the inward protrusion 12 and the inner circumferential surface of the mounting hole 11, causing the minimum inner diameter portion 12b to protrude downward. The recess 12e makes it possible to prevent molding defects such as sink marks from occurring on the outer surface of the cylindrical body 10 where the inward protrusion 12 is located.

[0022] Soft materials In this embodiment, a friction-induced discoloration member that rubs the surface of thermochromic handwriting to thermally discolor it is used as the soft member 20. As shown in Figure 1, the soft member 20 is made of an elastic material and comprises a large-diameter portion 23 that protrudes axially upward from the open end of the mounting hole 11, and a small-diameter portion 21 that is integrally connected downward from the large-diameter portion 23 and inserted into the mounting hole 11.

[0023] The material constituting the soft member 20 is preferably, for example, an elastic synthetic resin (rubber, elastomer), such as silicone resin, SBS resin (styrene-butadiene-styrene copolymer), SEBS resin (styrene-ethylene-butylene-styrene copolymer), fluorine-based resin, chloroprene resin, nitrile resin, polyester-based resin, ethylene propylene diene rubber (EPDM), or a mixture of two or more types of rubber elastic materials, and a mixture of a rubber elastic material and a synthetic resin.

[0024] The elastic synthetic resin constituting the soft member 20 is preferably made of a low-wear elastic material that generates almost no wear debris (eraser debris) when rubbed, rather than a high-wear elastic material (such as an eraser). The soft member 20 may also be an eraser, an input member of an input pen used in a portable information terminal, or the like.

[0025] The upper surface of large diameter portion 23 has a convex curved shape. A shoulder 23c that can axially abut against the open end of mounting hole 11 (specifically, the upper end of cylindrical body 10) is formed at the lower end of large diameter portion 23. The maximum outer diameter of large diameter portion 23 is set to be larger than the inner diameter of mounting hole 11 and smaller than the outer diameter of the upper end of cylindrical body 10.

[0026] ·External process An annular outward protrusion 22 is integrally formed on the outer circumferential surface of the small diameter portion 21. The outward protrusion 22 has a guide portion 22a formed of an inclined surface (i.e., a conical surface) whose outer diameter gradually increases upward. Furthermore, a maximum outer diameter portion 22b is formed above the guide portion 22a.

[0027] The maximum outer diameter of the outward protrusion 22 is set to be larger than the minimum inner diameter of the inward protrusion 12 and smaller than the inner diameter of the mounting hole 11 above the inward protrusion 12. In this embodiment, the maximum outer diameter of the outward protrusion 22 (i.e., the outer diameter of the maximum outer diameter portion 22b) is set to 4.9 mm, and the minimum inner diameter of the inward protrusion 12 (i.e., the inner diameter of the minimum inner diameter portion 12b) is set to 4.1 mm. The difference between the maximum outer diameter of the outward protrusion 22 and the minimum inner diameter of the inward protrusion 12 is preferably in the range of 0.5 mm to 2 mm (preferably 0.5 mm to 1 mm).

[0028] This makes it possible to reliably prevent the soft member 20 from falling off, and also enables the outward protrusions 22 to smoothly move over the inward protrusions 12. In other words, the soft member 20 is locked between the outward protrusions 22 and the inward protrusions 12 in the axial direction so as to be prevented from coming off.

[0029] Inner hole An inner hole 24 extending in the axial direction is formed inside the soft member 20. The lower end of the inner hole 24 opens axially downward. The upper end of the inner hole 24 is located inside the large diameter portion 23. The inner hole 24 forms the soft member 20 into a bottomed cylindrical shape with a closed upper end and an open lower end. In this embodiment, the inner hole 24 is formed at least radially inward of the outward protrusion 22, which facilitates elastic deformation of the outward protrusion 22 radially inward when the outward protrusion 22 rides over the inward protrusion 12.

[0030] Annular space The outer diameter a of the intermediate portion of the small diameter portion 21 (i.e., the portion between the outward protrusion 22 and the shoulder portion 23c) is set to be smaller than the inner diameter b of the portion of the mounting hole 11 above the inward protrusion 12. As a result, when the outward protrusion 22 and the inward protrusion 12 come into contact with each other just before the outward protrusion 22 climbs over the inward protrusion 12, an annular space 30 is formed between the outer peripheral surface of the small diameter portion 21 above the outward protrusion 22 and the inner peripheral surface of the mounting hole 11 above the inward protrusion 12.

[0031] When the outward protrusion 22 and the inward protrusion 12 are strongly pressed together, even if the small diameter portion 21 above the outward protrusion 22 expands radially outward due to elastic deformation, the annular space 30 is formed, so the outer peripheral surface of the small diameter portion 21 above the outward protrusion 22 is not strongly pressed against the inner peripheral surface of the mounting hole 11, and there is no risk of resistance when inserting the soft member 20. As a result, the outward protrusion 22 and the inward protrusion 12 can smoothly climb over each other. Specifically, the outer diameter a is set to 4.9 mm, and the inner diameter b is set to 5.6 mm.

[0032] Axial clearance As shown in FIG. 1, the axial length A from the lower end of the large diameter portion 23 (shoulder portion 23c of the soft member 20) to the upper end of the outward protrusion 22 (i.e., maximum outer diameter portion 22b) is set to be slightly larger than the axial length B from the upper end of the cylindrical body 10 to the lower end of the inward protrusion 12 of the mounting hole 11 (i.e., minimum inner diameter portion 12b).

[0033] In other words, when the opening end of the mounting hole 11 and the lower end (shoulder portion 23c) of the large diameter portion 23 are brought into axial contact with each other (when the upper end (i.e., maximum outer diameter portion 22b) of the outward protrusion 22 is positioned lower than the lower end (i.e., minimum inner diameter portion 12b) of the inward protrusion 12), an axial gap C is formed between the lower end of the inward protrusion 12 and the upper end of the outward protrusion 22. As a result, when the outward protrusion 22 climbs over the inward protrusion 12, even if the sliding between the outward protrusion 22 and the inward protrusion 12 is poor, the outward protrusion 22 can reliably climb over the inward protrusion 12.

[0034] Specifically, the effective range of the axial gap C is 0.05 mm to 1.0 mm (preferably 0.1 mm to 0.5 mm). The dimension of the axial gap C ensures that the inward protrusions 12 and the outward protrusions 22 can climb over each other when the soft member 20 is inserted. In this embodiment, specifically, the axial length A is set to 8 mm, and the axial length B is set to 7.9 mm.

[0035] ·Soft material insertion process The process of inserting the soft member 20 of this embodiment will be described. First, the lower end of the small diameter portion 21 of the soft member 20 is inserted into the upper opening of the mounting hole 11 of the cylindrical body 10. As the small diameter portion 21 is further inserted into the mounting hole 11, the guide portion 22a of the outward protrusion 22 of the small diameter portion 21 of the soft member 20 comes into contact with the guide portion 12a of the inward protrusion 12 of the mounting hole 11.

[0036] Then, just before the outward projections 22 climb over the inward projections 12, the outer peripheral surface of the small diameter portion 21 bulges outward in the radial direction. At this time, because the annular space 30 described above exists between the inner peripheral surface of the mounting hole 11 and the outer peripheral surface of the small diameter portion 21, the bulging outer peripheral surface of the small diameter portion 21 is not strongly pressed against the inner peripheral surface of the mounting hole 11. This does not interfere with the insertion of the soft member 20, and allows the outward projections 22 and the inward projections 12 to climb over each other smoothly.

[0037] 1, when the outward projections 22 and the inward projections 12 have finished climbing over each other, an axial gap C is formed between the upper end of the outward projections 22 and the lower end of the inward projections 12. This allows the outward projections 22 and the inward projections 12 to reliably climb over each other even if the outward projections 22 and the inward projections 12 do not slide smoothly over each other, without the need to apply a lubricant or the like.

[0038] Here, as shown in the above-mentioned Patent Document 1, the formation of the gap C makes it possible to reliably prevent the soft member 20 from falling off and also makes it easier to attach the soft member 20. However, there is a risk that the gap C will cause rattle in the axial direction of the soft member 20.

[0039] In other words, when a force is applied to the soft member 20 to pull it upward on the cylindrical body 10 (a force to pull out the soft member 20), the soft member 20 moves upward by the amount of gap C, which may create an axial gap between the soft member 20 and the end of the cylindrical body 10, which is undesirable from an appearance perspective.

[0040] Therefore, in the first embodiment of the present invention, the surface at the lower end of the inward projection 12 (below the minimum inner diameter portion 12b) is defined as the lower surface 12c, and the surface at the upper end of the outward projection 22 (above the maximum outer diameter portion 22b) is defined as the upper surface 22c. As shown in Fig. 1 or 2, the cylindrical body 10 includes a downward projection 12d that protrudes downward from the lower surface 12c. It is preferable that the upper surface 22c and the lower surface 12c are surfaces perpendicular to the axis.

[0041] As a result, even when the opening end of the mounting hole 11 and the lower end (shoulder portion 23c) of the large diameter portion 23 abut in the axial direction and an axial gap C is formed between the upper surface 22c and the lower surface 12c, the provision of the downward protrusions 12d can suppress axial rattle. Note that, as shown in FIG. 2, the downward protrusions 12d are four hemispherical protrusions, but they may also be multiple pillars such as square pillars or pyramids such as triangular pyramids. Furthermore, the hemispherical protrusions allow the outward protrusions 22 and the inward protrusions 12 to smoothly climb over each other.

[0042] In this embodiment, the downward protrusions 12d are provided on the lower surface 12c of the cylindrical body 10 and are therefore made of a hard material. The downward protrusions 12d are a plurality of protrusions spaced apart in the circumferential direction. As a result, after the soft member 20 is inserted into the cylindrical body 10, the downward protrusions 12d partially deform the upper surface 22c. Specifically, the downward protrusions 12d deform only the portion of the upper surface 22c that faces the downward protrusions 12d in the axial direction. In other words, the downward protrusions 12d are sunk (pressed) into the portion of the upper surface 22c with which they abut.

[0043] Therefore, in this embodiment, the formation of the downward protrusion 12d does not interfere with the fitting (axial locking) when attaching the cylindrical body 10 and the soft member 20. As described above, the configuration of this embodiment makes it possible to reliably prevent the soft member 20 from falling off, and also makes the attachment work of the soft member 20 easier, suppresses axial rattle of the soft member 20, and prevents the formation of a gap in the axial direction between the soft member 20 and the end of the cylindrical body 10.

[0044] In this embodiment, the gap C is equal to or less than the axial height of the downward protrusion 12d, which reliably suppresses axial wobble of the soft member 20 and prevents an axial gap from forming between the soft member 20 and the upper end of the cylindrical body 10, providing a configuration that is also excellent in terms of design (aesthetics).

[0045] Second Embodiment A second embodiment of the present invention is shown in Figures 3 and 4. Figure 3 is an enlarged vertical cross-sectional view of a main part showing a state in which a soft member 20 is inserted into a cylindrical body 10 of a writing implement in the second embodiment of the present invention. Figure 4 is a perspective view showing the features of the soft member 20 in Figure 3.

[0046] The second embodiment of the present invention differs from the first embodiment in that the second embodiment does not have the downward protrusion of the cylindrical body 10 provided in the first embodiment, but instead has an upward protrusion 22d that protrudes upward from the upper surface 22c of the soft member 20. The other configurations of the second embodiment are substantially the same as those of the first embodiment, and therefore detailed description thereof will be omitted.

[0047] In the second embodiment of the present invention, similarly to the first embodiment, the surface at the lower end (below the minimum inner diameter portion 12b) of the inward projection 12 is defined as the lower surface 12c, and the surface at the upper end (above the maximum outer diameter portion 22b) of the outward projection 22 is defined as the upper surface 22c. As shown in Fig. 3 or 4, the soft member 20 has an upper projection 22d that protrudes above the upper surface 22c.

[0048] As a result, even when the opening end of the mounting hole 11 and the lower end (shoulder portion 23c) of the large diameter portion 23 abut in the axial direction and an axial gap C is formed between the upper surface 22c and the lower surface 12c, the provision of the upper protrusions 22d can suppress axial rattle. As shown in FIG. 4, the upper protrusions 22d are four substantially hemispherical protrusions with rounded chamfers on their surfaces, but they may also be multiple hemispherical, prisms such as square prisms, or pyramids such as triangular pyramids. Furthermore, the protrusions with rounded chamfers on their surfaces allow the outward protrusions 22 and the inward protrusions 12 to smoothly climb over each other.

[0049] In this embodiment, the upper protrusions 22d are provided on the upper surface 22c of the soft member 20 and are therefore made of a soft material. The upper protrusions 22d are a plurality of protrusions spaced apart in the circumferential direction. As a result, after the soft member 20 is inserted into the cylindrical body 10, the upper protrusions 22d come into contact with the lower surface 12c and are deformed (compressed) in the axial direction.

[0050] Therefore, in this embodiment, the formation of the upper protrusion 22d does not interfere with the fitting (axial locking) when attaching the cylindrical body 10 and the soft member 20. As described above, the configuration of this embodiment makes it possible to reliably prevent the soft member 20 from falling off, and also makes the attachment work of the soft member 20 easier, suppresses axial rattle of the soft member 20, and prevents the formation of a gap in the axial direction between the soft member 20 and the end of the cylindrical body 10.

[0051] Furthermore, in this embodiment, the gap C is equal to or less than the axial height of the upper protrusion 22d, which reliably suppresses axial wobble of the soft member 20 and prevents an axial gap from forming between the soft member 20 and the upper end of the cylindrical body 10, thereby providing a configuration that is also excellent in terms of design (aesthetics).

[0052] From the above first and second embodiments, the present invention provides a mounting structure for a soft member, which is formed by inserting a soft member into a cylindrical body at the end of a writing implement, wherein the cylindrical body comprises a mounting hole that opens upward in the axial direction, an inward protrusion formed on the inner peripheral surface of the mounting hole, and a lower surface formed below the inward protrusion, and the soft member comprises a large diameter portion that protrudes upward from the opening end of the mounting hole, a small diameter portion that is integrally connected downward from the large diameter portion and is inserted into the mounting hole, an outward protrusion formed on the outer peripheral surface of the small diameter portion, and a lower surface above the outward protrusion and an upper surface formed toward the mounting hole, wherein the soft member is inserted into the mounting hole by the outward protrusion and the inward protrusion being axially engaged to prevent slippage, the opening end of the mounting hole and the lower end of the large diameter portion are in axial contact, an axial gap is provided between the upper surface and the lower surface, and at least one of an upper protrusion protruding upward from the upper surface or a lower protrusion protruding downward from the lower surface is formed, and the upper protrusion and the lower protrusion are a plurality of protrusions spaced apart in the circumferential direction.

[0053] According to the present invention, the outward projection and the inward projection each have an upper surface and a lower surface, and at least one of an upper projection that projects upward from the upper surface or a lower projection that projects downward from the lower surface is formed, and the upper projection and the lower projection are a plurality of projections spaced apart in the circumferential direction, which makes it possible to reliably prevent the soft member from falling off, and also makes the installation work of the soft member easier, suppresses axial rattle of the soft member, and prevents the formation of an axial gap between the soft member and the end of the cylindrical body.

[0054] <Third embodiment> A third embodiment of the present invention is shown in Figures 5 and 6. Figure 5 is an enlarged longitudinal cross-sectional view of a main part of a writing implement according to the third embodiment of the present invention, showing a state in which a soft member 20 is inserted into a cylindrical body 10. Figure 6 is a perspective view showing the features of the cylindrical body 10 of Figure 5.

[0055] The third embodiment of the present invention differs from the first embodiment in that the cylindrical body 10 does not have the downward protrusion provided in the first embodiment, and instead has an upper surface 11a formed above the open end of the mounting hole 11, an upper protrusion 11b protruding upward from the upper surface 11a, and a wall portion 13 protruding upward from the upper surface 11a. The other configurations of the third embodiment are substantially the same as those of the first embodiment, so detailed description thereof will be omitted.

[0056] ·Soft material insertion process 5, when the outward protrusion 22 and the inward protrusion 12 have finished climbing over each other, an axial gap C is formed between the surface of the opening end of the mounting hole 11 (the upper surface 11a described below) and the surface of the lower end of the shoulder portion 23c of the soft member 20 (the lower surface 23a described below). This allows the outward protrusion 22 and the inward protrusion 12 to reliably climb over each other even if the sliding between the outward protrusion 22 and the inward protrusion 12 is poor.

[0057] Here, as shown in the above-mentioned Patent Document 1, the formation of the gap C makes it possible to reliably prevent the soft member 20 from falling off and also makes it easier to attach the soft member 20. However, there is a risk that the gap C will cause rattle in the axial direction of the soft member 20.

[0058] Therefore, in the third embodiment of the present invention, the surface of the lower end of shoulder portion 23c of soft member 20 is defined as lower surface 23a, and the surface of the opening end of mounting hole 11 of cylindrical body 10 is defined as upper surface 11a. As shown in Fig. 5 or 6, cylindrical body 10 has an upper protrusion 11b that protrudes upward from upper surface 11a. Note that upper surface 11a and lower surface 23a are preferably surfaces perpendicular to the axis.

[0059] The cylindrical body 10 also has an annular wall portion 13 that protrudes upward from the upper surface 11a. The wall portion 13 is formed integrally with the cylindrical body 10. The inner diameter of the wall portion 13 is larger than the inner diameter of the opening end of the mounting hole 11 and smaller than the outer diameter of the maximum outer diameter portion 22b (shoulder portion 23c) of the large diameter portion 23.

[0060] As a result, even if an axial gap C is formed between the upper surface 11a and the lower surface 23a when the outward protrusions 22 and the inward protrusions 12 have finished climbing over each other, the provision of the upper protrusions 11b makes it possible to suppress rattling in the axial direction. As shown in FIG. 6, the upper protrusions 11b are four substantially hemispherical protrusions with rounded chamfers on their surfaces, but they may also be multiple hemispherical protrusions, prisms such as square prisms, or pyramids such as triangular pyramids. Furthermore, the protrusions with rounded chamfers on their surfaces enable the outward protrusions 22 and the inward protrusions 12 to climb over each other smoothly.

[0061] In this embodiment, the upper protrusions 11b are provided on the upper surface 11a of the cylindrical body 10 and are therefore made of a hard material. The upper protrusions 11b are a plurality of protrusions spaced apart in the circumferential direction. As a result, after the soft member 20 is inserted into the cylindrical body 10, the upper protrusions 11b partially deform the lower surface 23a. Specifically, the upper protrusions 11b deform only the portion of the lower surface 23a that faces the upper protrusions 11b in the axial direction. In other words, the upper protrusions 11b are sunk (pressed) into the portion of the lower surface 23a with which they abut.

[0062] Therefore, in this embodiment, the formation of the upper protrusion 11b does not interfere with the fitting (axial locking) when attaching the cylindrical body 10 and the soft member 20. As described above, the configuration of this embodiment makes it possible to reliably prevent the soft member 20 from falling off, and also makes the attachment work of the soft member 20 easier, suppresses axial rattle of the soft member 20, and prevents the formation of a gap in the axial direction between the soft member 20 and the end of the cylindrical body 10.

[0063] In this embodiment, the gap C is equal to or smaller than the axial height of the upper protrusion 11b, which makes it possible to reliably prevent the soft member 20 from wobbling in the axial direction.

[0064] The cylindrical body 10 also has an annular wall portion 13 that protrudes upward from the upper surface 11a. The wall portion 13 is formed integrally with the cylindrical body 10. As shown in Fig. 5, in this embodiment, an axial gap corresponding to gap C is created between the open end of the mounting hole 11 and the lower end (shoulder portion 23c) of the large diameter portion 23. However, the configuration including the wall portion 13 can cover the gap so that it cannot be seen from the outside, thereby providing a configuration that is also excellent in terms of design (aesthetics).

[0065] The inner diameter of wall portion 13 is larger than the inner diameter of the opening end of mounting hole 11 and smaller than the outer diameter of maximum outer diameter portion 22b (shoulder portion 23c) of large diameter portion 23. The height of wall portion 13 (the axial protrusion height from upper surface 11a) is preferably larger than the axial height of upper protrusion 11b. This ensures that the gap is completely covered, making it completely invisible from the outside, and providing a form that is excellent in design (aesthetics).

[0066] The wall portion 13 of this embodiment can provide a form that is similarly excellent in terms of design (beauty) even when provided in the first and second embodiments described above.

[0067] <Fourth embodiment> A fourth embodiment of the present invention is shown in Figures 7 and 8. Figure 7 is an enlarged vertical cross-sectional view of a main part showing a state in which a soft member 20 is inserted into a cylindrical body 10 of a writing implement in the fourth embodiment of the present invention. Figure 8 is a perspective view showing the features of the soft member 20 in Figure 7.

[0068] The fourth embodiment of the present invention differs from the third embodiment in that it does not have the upward protrusion of the cylindrical body 10 provided in the third embodiment, but instead has a downward protrusion 23b that protrudes downward from the lower surface 23a of the soft member 20. The other configurations of the fourth embodiment are substantially the same as those of the first and third embodiments, and therefore detailed description thereof will be omitted.

[0069] In the fourth embodiment of the present invention, similarly to the third embodiment, the surface of the lower end of the shoulder portion 23c of the soft member 20 is defined as the lower surface 23a, and the surface of the opening end of the mounting hole 11 of the cylindrical body 10 is defined as the upper surface 11a. As shown in Fig. 7 or 8, the soft member 20 has a downward protrusion 23b that protrudes downward from the lower surface 23a. It is preferable that the upper surface 11a and the lower surface 23a are surfaces perpendicular to the axis.

[0070] As a result, even if an axial gap C is formed between the upper surface 11a and the lower surface 23a when the outward protrusions 22 and the inward protrusions 12 have finished climbing over each other, the provision of the lower protrusions 23b can suppress axial rattle. As shown in FIG. 8, the lower protrusions 23b are four substantially hemispherical protrusions with rounded chamfers on their surfaces, but they may also be multiple hemispherical protrusions, prisms such as square prisms, or pyramids such as triangular pyramids. Furthermore, the protrusions with rounded chamfers on their surfaces enable the outward protrusions 22 and the inward protrusions 12 to climb over each other smoothly.

[0071] In this embodiment, the lower protrusions 23b are provided on the lower surface 23a of the soft member 20 and are therefore made of a soft material. The lower protrusions 23b are a plurality of protrusions spaced apart in the circumferential direction. As a result, after the soft member 20 is inserted into the cylindrical body 10, the lower protrusions 23b come into contact with the upper surface 11a and are deformed (compressed) in the axial direction.

[0072] Therefore, in this embodiment, the formation of the downward protrusion 23b does not interfere with the fitting (axial locking) when attaching the cylindrical body 10 and the soft member 20. As described above, the configuration of this embodiment makes it possible to reliably prevent the soft member 20 from falling off, and also makes the attachment work of the soft member 20 easier, suppresses axial rattle of the soft member 20, and prevents the formation of a gap in the axial direction between the soft member 20 and the end of the cylindrical body 10.

[0073] In this embodiment, the gap C is equal to or less than the axial height of the downward protrusion 23b, which makes it possible to reliably prevent the soft member 20 from wobbling in the axial direction.

[0074] The inner diameter of the wall portion 13 is larger than the inner diameter of the opening end of the mounting hole 11 and smaller than the outer diameter of the maximum outer diameter portion 22b (shoulder portion 23c) of the large diameter portion 23. The height of the wall portion 13 (the height of the wall portion 13 projecting in the axial direction from the upper surface 11a) is preferably larger than the axial height of the downward projection 23b. This ensures that the gap is completely covered, making it completely invisible from the outside, and providing a form that is excellent in terms of design (aesthetics).

[0075] From the third and fourth embodiments described above, the present invention provides a mounting structure for a soft member, which is formed by inserting a soft member into a cylindrical body at the end of a writing implement, wherein the cylindrical body comprises a mounting hole that opens upward in the axial direction, an inward protrusion formed on the inner peripheral surface of the mounting hole, an upper surface formed above the opening end of the mounting hole, and a wall portion that protrudes upward from the upper surface, the inner diameter of the wall portion being larger than the inner diameter of the opening end of the mounting hole, and the soft member comprises a large diameter portion that protrudes upward from the opening end of the mounting hole, and a large diameter portion that is integrally connected downward from the large diameter portion and is inserted into the mounting hole. the soft member is inserted into the mounting hole by the outward protrusion and the inward protrusion being axially locked to prevent slipping out, an axial gap is provided between the upper surface and the lower surface, and at least one of an upper protrusion protruding upward from the upper surface or a lower protrusion protruding downward from the lower surface is formed, and the upper protrusion and the lower protrusion are a plurality of protrusions spaced apart in the circumferential direction.

[0076] According to the present invention, the connector has an upper surface formed above the opening end of the mounting hole, a lower surface formed below the large-diameter portion, and a wall portion projecting upward from the upper surface, and is provided with at least one of an upper protrusion projecting upward from the upper surface and a lower protrusion projecting downward from the lower surface, the upper protrusion and the lower protrusion being a plurality of protrusions spaced apart in the circumferential direction, which makes it possible to reliably prevent the soft member from falling off, facilitates the installation of the soft member, suppresses axial rattle of the soft member, and prevents the formation of an axial gap between the soft member and the end of the cylindrical body. [Explanation of symbols]

[0077] 10 Cylinder 11 Mounting hole 11a Upper side 11b Superior process 12 Introvert process 12a Guide part 12b Minimum inner diameter 12c lower side 12d downward process 12e Recess 13 Wall 20 Soft materials 21 Small diameter section 22 External process 22a Guide part 22b Maximum outer diameter 22c upper side 22d superior process 23 Large diameter section 23a Bottom 23b Lower process 23c Shoulder 24 inner hole 30 Annular Space A: The axial length from the bottom end of the large diameter part to the top end of the outward projection B: Axial length from the top of the cylinder to the bottom of the inward projection C-axis clearance a Outer diameter of the middle part of the small diameter section b Inner diameter of the part above the inward protrusion of the mounting hole

Claims

1. A soft member mounting structure in which a soft member is inserted into a cylindrical body at the end of a writing implement, the cylindrical body includes a mounting hole that opens axially upward, an inward protrusion formed on an inner peripheral surface of the mounting hole, and a lower surface formed below the inward protrusion, the soft member comprises a large diameter portion protruding upward from the opening end of the mounting hole, a small diameter portion integrally connected downward from the large diameter portion and inserted into the mounting hole, an outward protrusion formed on the outer circumferential surface of the small diameter portion, and an upper surface formed above the outward protrusion, the soft member is inserted into the mounting hole by the outward protrusion and the inward protrusion being axially retained and locked, the opening end of the mounting hole and the lower end of the large diameter portion are in axial contact with each other, and an axial gap is provided between the upper surface and the lower surface, At least one of an upper protrusion protruding upward from the upper surface and a lower protrusion protruding downward from the lower surface is formed, The upper and lower protrusions are a plurality of protrusions spaced apart in the circumferential direction.

2. A soft member mounting structure in which a soft member is inserted into a cylindrical body at the end of a writing implement, the cylindrical body includes a mounting hole that opens upward in the axial direction, an inward protrusion formed on the inner peripheral surface of the mounting hole, an upper surface formed above an opening end of the mounting hole, and a wall portion that protrudes upward from the upper surface, the inner diameter of the wall portion being larger than the inner diameter of the opening end of the mounting hole; the soft member comprises a large diameter portion protruding upward from an opening end of the mounting hole, a small diameter portion integrally connected downward from the large diameter portion and inserted into the mounting hole, an outward projection formed on an outer peripheral surface of the small diameter portion, and a lower surface formed below the large diameter portion, the soft member is inserted into the mounting hole by the outward protrusion and the inward protrusion being axially retained and locked, and an axial gap is provided between the upper surface and the lower surface, At least one of an upper protrusion protruding upward from the upper surface and a lower protrusion protruding downward from the lower surface is formed, The upper and lower protrusions are a plurality of protrusions spaced apart in the circumferential direction.

3. 3. The soft member mounting structure according to claim 2, wherein the height of the wall portion projecting from the upper surface in the axial direction is greater than the height of the upper protrusion or the lower protrusion in the axial direction.

4. 4. The soft member mounting structure according to claim 1, wherein the gap is equal to or smaller than the axial height of the upper protrusion and the lower protrusion.

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