Spacer manufacturing method

Abstract

To provide a manufacturing method of a spacer which dispenses with a preform process, and can improve productivity.SOLUTION: In a manufacturing method of a spacer for manufacturing the spacer arranged in a cooling water flow passage which is formed at a cylinder block of an internal combustion engine in a state for surrounding a cylinder bore, and having a support body composed of resin, and having a protrusive bent part, and a porous body 3 attached to a side face including a protrusive bent face of the protrusive bent part of the support body by using a molding mold 10, a plurality of positioning protrusions 11d are formed at the molding mold with a bottom part 11c of a recessed bent part 11b corresponding to an apex of the protrusive bent part of the support body sandwiched therebetween, the sheet-shaped porous body is arranged at the molding mold by locking both-side end edges of the porous body by peripheral edges of the positioning protrusions in a state that the porous body is bent so as to progress along the recessed bent part of the molding mold, and the resin is injected into the molding mold, thus performing insert molding.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method of manufacturing a spacer that is disposed in a cooling water flow passage formed in a cylinder block of an internal combustion engine so as to surround a cylinder bore. [Background technology]

[0002] In the cooling water flow passage of an internal combustion engine, a spacer for regulating the flow rate and flow speed of the cooling water is inserted from an opening and placed therein (see, for example, Patent Document 1). For example, in the spacer disclosed in Patent Document 1, a porous body is attached to the cylinder bore side surface of a support (spacer body) made of a rigid body such as synthetic resin, which expands when it comes into contact with the cooling water and comes into contact with the wall surface of the cylinder bore side of the cooling water flow passage. Since the porous body attached to the spacer body in this way has a thin thickness before expanding, the spacer can be smoothly inserted into the cooling water flow passage with small insertion resistance, and can be expanded after being placed in the cooling water flow passage to regulate the flow of the cooling water.

[0003] The spacer as described above is integrally molded by introducing molten resin into a mold in a state where the porous body is placed in the mold. In such a spacer, the spacer body often has a curved surface portion, and it is required to place the porous body on the curved surface portion as well. For example, when the porous body is placed on the convex curved surface of the spacer body, it is necessary to place the porous body on the concave curved surface of the mold. For example, FIG. 17 of Patent Document 1 discloses a configuration in which the porous body is placed in a recess provided on the concave curved surface of the mold. In addition, in order to prevent the porous body from being displaced when the molten resin is introduced, a configuration is adopted in which a protrusion provided on the mold is fitted with a through hole provided in the porous body. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-128256 A Summary of the Invention [Problem to be solved by the invention]

[0005] When placing a porous body in a recess of a mold as disclosed in Patent Document 1, it is possible to adopt a method of preforming a planar sheet-like porous body into a shape that matches the recess of the mold prior to the step. However, from the viewpoint of improving production throughput, it is preferable not to adopt such a preforming step.

[0006] Therefore, instead of performing the preforming process, it is possible to adopt a configuration in which the above-mentioned protrusions provided on the mold are lengthened, and the porous body is placed in the recess of the mold. With such a configuration, it is possible to prevent the porous body from being separated from the mold, but on the other hand, it will lead to a decrease in production throughput due to an increase in the amount of mold opening. On the other hand, it is possible to prevent the porous body from being separated by setting the tightening margin of the through-hole of the porous body corresponding to the above-mentioned protrusions provided on the mold. However, with such a configuration, the molded product cannot be smoothly removed from the mold after the mold is opened, leading to a decrease in production throughput.

[0007] The present invention has been made in view of the above circumstances, and has an object to provide a method for manufacturing a spacer that does not require a preforming step and can improve productivity. [Means for solving the problem]

[0008] In order to achieve the above object, the method for manufacturing a spacer of the present invention is a method for manufacturing a spacer by using a molding die, the spacer being disposed in a cooling water flow passage formed in a cylinder block of an internal combustion engine so as to surround a cylinder bore, the spacer including a support body made of resin and having a convex curved portion, and a porous body attached to a side of the support body including a convex curved surface of the convex curved portion, the molding die being provided with a plurality of positioning protrusions sandwiching bottoms of concave curved portions corresponding to tops of the convex curved portion of the support body. The protruding length of the plurality of positioning protrusions is set to be greater than the thickness of the porous body sheet and less than the thickness of the support, It is in sheet form. On both sides of the mold, there are no projections or recesses that can be engaged with the mold.The porous body is bent so as to fit the concave curved portion of the mold, and both end edges of the porous body are aligned around the positioning protrusions. surface The insert molding method is characterized in that the mold is placed on the mold while being engaged with a mating member, and resin is injected into the mold to perform insert molding.

[0009] In this method of manufacturing a spacer, the porous body can be positioned in the mold. At this time, the positioning protrusions are provided at positions sandwiching the bottom of the concave curved portion of the mold, so that the porous body can be maintained in a curved state by the positioning protrusions. As a result, a spacer can be manufactured in which the porous body is attached to a position corresponding to the convex curved portion. Effect of the Invention

[0010] According to the present invention, it is possible to provide a spacer manufacturing method that does not require a preforming step and can improve productivity. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view showing an example of a spacer according to an embodiment of the present invention. [Diagram 2] 1 is a cross-sectional view showing a schematic diagram of an example of a spacer according to an embodiment of the present invention. [Diagram 3] 5(a) to 5(d) are cross-sectional views that diagrammatically show an example of a molding process for a spacer according to one embodiment of the present invention. [Figure 4] 1A is an enlarged cross-sectional view showing a schematic diagram of the relationship between a through hole of a porous body of a spacer according to an embodiment of the present invention and a positioning protrusion of a casting mold, and FIG. 1B is a plan view showing an example of a porous body of a spacer according to an embodiment of the present invention. [Diagram 5] 1A is a longitudinal sectional view showing a state where a spacer according to an embodiment of the present invention is used, and FIG. 1B shows a state where the porous body has expanded. [Figure 6]5(a) to 5(c) are diagrams showing schematic diagrams illustrating the positional relationship between a porous body and a positioning protrusion in a molding process of a spacer according to one embodiment of the present invention. [Figure 7] 5(a) to 5(d) are diagrams showing schematic diagrams illustrating the positional relationship between a porous body and a positioning protrusion in a molding process of a spacer according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described in more detail with reference to the drawings. FIG. 1 is a perspective view showing an example of a spacer in one embodiment of the present invention. FIG. 2 is a cross-sectional view showing an example of a spacer in one embodiment of the present invention. FIG. 2 corresponds to a cross-sectional view of the spacer shown in FIG. 1. For the sake of explanation, this embodiment illustrates a spacer arranged in a groove-shaped open deck type cooling water flow path arranged around a cylinder bore in a cylinder block in which two cylinder bores are arranged in series. In addition, in this specification, the direction corresponding to the axial direction of the cylinder bore (depth direction of the cooling water flow path) in the spacer is appropriately referred to as the up-down direction, and the direction corresponding to the arrangement direction of the cylinder bores is appropriately referred to as the left-right direction.

[0013] 1 and 2, the spacer 1 of this embodiment includes a support 2 made of resin, and a porous body 3 attached to the support 2. The support 2 includes two arc sections 21 each constituting a partial cylindrical surface, and a connecting portion 22 connecting the two adjacent arc sections 21. The connecting portion 22 includes a convex curved surface 22a that smoothly connects the concave sides (hereinafter referred to as the concave curved surface 21a) of the two arc sections 21, and the porous body 3 is attached to the side surface including the convex curved surface 22a. Hereinafter, in this specification, the connecting portion 22 including the convex curved surface 22a will be referred to as the convex curved portion 22.

[0014] As described above, the convex curved portion 22 (convex curved surface 22a) is a portion that connects two adjacent arc portions 21 (partial cylindrical surfaces). That is, in the cross section shown in FIG. 2, the convex curved portion 22 (convex curved surface 22a) is an area of ​​the surface of the support 2 that is composed of the concave curved surface 21a and the convex curved surface 22a, where the curvature is different from the curvature of the surface portion that constitutes the partial cylindrical surface. In this specification, the most protruding portion of the convex curved surface 22a is referred to as the apex 22b of the convex curved portion 22. In the spacer 1 of this embodiment, the convex curved portion 22 has the same shape in the vertical direction, so the apex 22b of the convex curved portion 22 is a straight line along the vertical direction.

[0015] The shape of the spacer 1 as described above is a shape that matches the cooling water flow path of the cylinder block, and the concave side 21a is disposed in the cooling water flow path facing the cylinder bore. The convex curved surface 22a is disposed in the cooling water flow path facing the cylinder block (inter-cylinder bore area) between the cylinder bores arranged in series in the cylinder block. In this embodiment, two spacers 1 are connected with the concave curved surfaces 21a and the convex curved surfaces 22a of the spacers 1 facing each other, thereby forming a shape that corresponds to the overall shape of the cooling water flow path of the cylinder block. The two connected spacers 1 are disposed in the cooling water flow path of the cylinder block.

[0016] The porous body 3 is configured as a rectangular sheet-like member and has flexibility. As described above, the porous body 3 is attached to the side of the support 2 including the convex curved surface 22a. Although not particularly limited, in this embodiment, the porous body 3 is attached to the support 2 in a state in which it covers a part of the convex curved surface 22a in the vertical direction and both ends in the left-right direction overlap each arc portion 21. In other words, the cylinder bore side surfaces of both ends of the porous body 3 are continuous with the concave curved surface 21a of the arc portion 21 and form part of the concave curved surface 21a. Here, the length of the porous body 3 is smaller than the length of the support 2 in the axial direction (vertical direction) of the partial cylindrical surface that forms the concave curved surface 21a. In this embodiment, the length of the porous body 3 in the vertical direction is about half the length of the support 2 in the vertical direction, and the porous body 3 is disposed approximately in the center of the support 2 in the vertical direction.

[0017] The porous body 3 also includes a through hole 4 penetrating the sheet-like porous body 3 in the thickness direction. As shown in FIG. 1 and FIG. 2, a plurality of through holes 4 are provided with the apex 22b of the convex curved portion 22 sandwiched therebetween. In this embodiment, the porous body 3 includes a pair (two) of through holes 4 provided at an equal distance from the apex 22b of the convex curved portion 22. Each of the through holes 4 is provided at the center in the vertical direction of the porous body 3. Also, the through hole 4 is provided at the end of the convex curved portion 22 in the horizontal direction. That is, in the cross section shown in FIG. 2, each of the through holes 4 is provided at the position of the inflection point closest to the apex 22b of the convex curved portion 22 in the curve corresponding to the surface of the support 2 formed by the concave curved surface 21a and the convex curved surface 22a.

[0018] In the above-mentioned configuration, the material of the resin constituting the support 2 is not particularly limited as long as it can be injection molded. For example, a hard synthetic resin such as a polyamide resin can be used. In addition, the material constituting the porous body 3 is not particularly limited as long as it can regulate the flow path of the cooling water integrally with the support 2 in the above-mentioned cooling water flow path. For example, a material having a characteristic of being maintained in a compressed state and expanding when a predetermined external factor is added, such as a cellulose sponge, a water-swellable sponge, a foamed body or a non-foamed porous body maintained in a compressed state by a water-soluble binder, or a binder that dissolves or melts at a temperature higher than a predetermined temperature, can be used.

[0019] In this embodiment, a cellulose sponge in a compressed state is used as a particularly suitable material for the porous body 3. The cellulose sponge is maintained in a compressed state. When the sponge comes into contact with water, the contact with water becomes an external factor, and the addition of the external factor triggers the sponge to expand to the state before compression. More specifically, the cellulose sponge is a natural material made of cellulose derived from pulp and natural fibers (e.g., cotton, etc.) added as reinforcing fibers. Cellulose has a hydrophilic group (OH) and has a chemical property of being easily compatible with water. The cellulose sponge is a porous material, and when it is dried under pressure, the cellulose molecules form hydrogen bonds between each other to maintain the sponge in a compressed state, while when it is exposed to water from this state, the water molecules dissociate the hydrogen bonds between the cellulose molecules to restore the sponge from the compressed state.

[0020] In the spacer 1 of this embodiment, the porous body 3 is integrated with the support 2 by insert molding. Fig. 3(a) to Fig. 3(d) are cross-sectional views that typically show an example of a molding process for a spacer according to one embodiment of the present invention. Fig. 3(a) is a cross-sectional view that typically shows a mold in which the porous body is placed. Fig. 3(b) is a cross-sectional view that typically shows a step of placing the porous body in the mold. Fig. 3(c) is a cross-sectional view that typically shows a state in which the mold is closed. Fig. 3(d) is a cross-sectional view that typically shows a step of integrally molding the porous body and resin.

[0021] As shown in Figures 3(c) and 3(d), the spacer 1 is manufactured by a molding die 10. A lower die 11 and an upper die 13 constituting the molding die 10 of this embodiment are configured to form a cavity 12 corresponding to the shape of the spacer 1 when the die is clamped.

[0022] As shown in FIG. 3(a), the lower mold 11 has a convex curved portion 11a corresponding to each concave curved surface 21a of the spacer 1, and a concave curved portion 11b corresponding to the convex curved surface 22a of the spacer 1. The concave curved portion 11b of the lower mold 11 has a bottom 11c of the concave curved portion 11b corresponding to the top 22b of the convex curved portion 22, and two positioning protrusions 11d are provided with the bottom 11c of the concave curved portion 11b sandwiched between them. As shown in FIG. 3(c), the protruding length of the positioning protrusion 11d (the length from the surface of the lower mold 11) is set to be less than the height of the cavity 12 (the thickness of the support 2), and a gap is formed between the surface of the upper mold 13 and the tip of the positioning protrusion 11d when the molds are closed. In addition, in this embodiment, as a preferred embodiment, the protruding length of the positioning protrusion 11d is set to be greater than the sheet thickness of the porous body 13.

[0023] As shown in FIG. 3(b), in a state where the porous body 3 is bent along the concave curved portion 11b, the positioning protrusion 11d is inserted into the through hole 4 of the porous body 3. This positions the arrangement of the porous body 3 in the lower mold 11. Furthermore, as a result of the porous body 3 being locked by the positioning protrusion 11d, the porous body 3 is prevented from being removed from the lower mold 11. The positioning protrusion 11d is formed in a cylindrical shape whose cross-sectional area cut in a direction perpendicular to the axial direction is slightly larger than the opening shape of the through hole 4. Then, when the positioning protrusion 11d is inserted into the through hole 4, the positioning protrusion 11d pushes the through hole 4 wide, and the opening of the through hole 4 takes a shape following the peripheral surface 11e of the positioning protrusion 11d.

[0024] Here, the details of the configuration for locking the porous body 3 by the positioning protrusion 11d will be described. Fig. 4(a) is an enlarged cross-sectional view showing a schematic relationship between a through hole of a porous body provided in a spacer according to one embodiment of the present invention and a positioning protrusion of a molding die. Fig. 4(b) is a plan view showing an example of a porous body provided in a spacer according to one embodiment of the present invention. Note that Fig. 4(a) shows the porous body in a curved state, whereas Fig. 4(b) shows the porous body in a flat stretched state (uncurved state).

[0025] As described above, when the porous body 3 is placed in the concave curved portion 11b of the lower mold 11, the porous body 3 is curved to conform to the surface shape of the concave curved portion 11b, and the positioning protrusion 11d of the lower mold 11 is inserted into the through hole 4 of the porous body 3 in this state. In the porous body 3 of this embodiment, as shown in FIG. 4(a), the through hole 4 is formed so that the distance L1 of the through hole 4 when the porous body 3 is curved to a shape that matches the surface shape of the concave curved portion 11b of the lower mold 11 is slightly larger than the distance L2 between the corresponding positioning protrusions 11d. As shown in FIG. 4(a), the distance L1 here is the shortest distance (edge-to-edge distance) between the opening edges of the two through holes 4. Also, the distance L2 is the shortest distance (edge-to-edge distance) between the peripheral surfaces of the two positioning protrusions 11d.

[0026] In the case where such a configuration is adopted, when the curved porous body 3 tries to return to a flat shape, the center side of the porous body 3 on the inner side surface 4a of the through hole 4 is pressed against the peripheral surface 11e of the positioning protrusion 11d facing the inner side surface. As a result, the porous body 3 is locked by the positioning protrusion 11d while maintaining the curved shape. Therefore, by adopting the above-mentioned configuration, even if the porous body 3 is placed on the concave curved portion 11b of the lower mold 11 without performing preforming, the porous body 3 can be prevented from being separated from the lower mold 11. Note that, if the difference between the above-mentioned distance L1 and the distance L2 is large (L1>>L2), when the through hole 4 is fitted into the positioning protrusion 11d, wrinkles and the like will occur in the porous body 3 between the positioning protrusions 11d. On the other hand, if the distance L2 is larger than the distance L1 (L2>L1), a gap will occur between the porous body 3 and the surface of the concave curved portion 11b of the lower mold 11 between the positioning protrusions 11d. If such a gap occurs, the molten resin will flow into the gap during insert molding, degrading the quality of the spacer 1. Therefore, as described above, it is preferable to configure the distance L1 to be slightly larger than the distance L2. In other words, it is preferable to configure the distance L1 to be slightly larger than the distance L2 so as to satisfy the conditions that no wrinkles occur in the porous body 3 between the positioning protrusions 11d, and no gap occurs between the porous body 3 and the surface of the concave curved portion 11b of the lower mold 11 between the positioning protrusions 11d. The relationship between the distance L1 and the distance L2 that satisfies such a condition cannot be generalized because it is appropriately set according to the size and shape of the spacer 1 and the porous body 3, but for example, a configuration can be adopted in which the distance L1 is larger than the distance L2 by about half to one-third of the thickness of the compressed porous body 3.

[0027] In this embodiment, although not particularly limited, the positioning protrusion 11d is cylindrical (perfectly circular cylindrical), and the through hole 4 of the porous body 3 is not circular, but elliptical with its major axis aligned along the direction in which an external force is applied to bend the porous body 3, as shown in FIG. 4(b). By adopting such a configuration, when the porous body 3 is bent into a shape that matches the surface shape of the concavely curved portion 11b, the shape of the through hole 4 as viewed from the axial direction of the positioning protrusion 11d can be made into a perfect circle. This allows the through hole 4 to be fitted into the positioning protrusion 11d more smoothly than when the through hole 4 is made into a perfect circle.

[0028] When the placement of the porous body 3 in the lower die 11 is completed in the above manner, the upper die 13 is clamped to the lower die 11. As shown in Fig. 3(c), in this state, molten resin 14 is injected into the cavity 12 from a gate (not shown) of the molding die 10, and insert molding is performed. At this time, the porous body 3 is insert molded in a state in which it is deformed into a shape that fits the surface of the lower die 11 by the injection pressure of the molten resin 14, as shown in Fig. 3(d).

[0029] In the above insert molding, the porous body 3 is aligned and maintained in position by the engagement between the through hole 4 and the positioning protrusion 11d, so that the porous body 3 does not shift in position due to the flow pressure of the molten resin 14 in the cavity 12. Furthermore, in this embodiment, the porous body 3 is engaged with the multiple positioning protrusions 11d in a curved state, so there is no need to preform the porous body 3 when placing it in the lower mold 11. Therefore, it is possible to improve the productivity of the spacer 1. Furthermore, in this embodiment, the through hole 4 is evenly spaced from the apex 22b of the convex curved portion 22 and is provided in the center of the porous body 3 in the vertical direction, so that when the porous body 3 is positioned in the concave curved portion 11b of the lower mold 11 by the positioning protrusion 11d, the porous body 3 can be maintained in an evenly curved state.

[0030] When the molding of the spacer 1 is completed and the spacer 1 is demolded, the spacer 1 is obtained in which the porous body 3 is reliably integrated with the surface including the convex curved surface 22a of the support 2, as shown in Figs. 1 and 2. In the spacer 1 of this embodiment, as described above, the tip of the positioning protrusion 11d provided on the lower die 11 of the molding die 10 is configured not to contact the upper die 13. Therefore, as shown in Fig. 2, in the spacer 1, the support 2 is formed in a state where it covers the through hole 4 of the porous body 3. Therefore, when it is placed in the above-mentioned cooling water flow path, the cooling water does not flow between the front and back of the spacer 1 through the through hole 4. Therefore, the cooling water toward the cylinder bore side can be maintained at a predetermined amount, and the expected deterioration of the function of the spacer 1 can be suppressed.

[0031] The spacer 1 as described above is inserted into the cooling water flow passage in the cylinder block through its opening. Figures 5(a) and 5(b) are longitudinal sectional views that typically show a state in which the spacer 1 according to one embodiment of the present invention is in use. Note that Figures 5(a) and 5(b) are partial longitudinal sectional views along a plane that includes the central axis of the cylinder bore of the cylinder block and passes through the porous body 3 of the spacer 1.

[0032] FIG. 5(a) shows a state in which the spacer 1 is disposed in the cooling water flow passage 5 of the cylinder block 40. As shown in FIG. 5(a), the spacer 1 is disposed in the cooling water flow passage 5 in a state in which the porous body 3 fixed to the support 2 faces the cylinder bore 41. The spacer 1 is disposed in the cooling water flow passage 5 through the opening 51 of the cooling water flow passage 5. At this time, the porous body 3 is maintained in a compressed state, and the porous body 3 is unlikely to interfere with the inner inner wall portion 5a of the cooling water flow passage 5 on the cylinder bore 41 side, and can be smoothly inserted. Furthermore, in the compressed state of the porous body 3, the surfaces of the porous body 3 on the cylinder bore side at both ends do not protrude from the concave curved surface 21a of the arc portion 21, and are continuous with the concave curved surface 21a of the arc portion 21, so that the porous body 3 is unlikely to interfere with the inner inner wall portion 5a of the cooling water flow passage 5 on the cylinder bore 41 side. Then, as shown in FIG. 5(b), a cylinder head 42 is fastened to the upper surface of the cylinder block 40 via a head gasket 43, and then cooling water 6 is introduced into the cooling water flow path 5 from a cooling water inlet port (not shown).

[0033] As described above, when the cooling water 6 is introduced into the cooling water flow passage 5, the cooling water 6 comes into contact with the porous body 3 made of cellulose sponge, and the porous body 3 expands toward the cylinder bore 41. As the porous body 3 expands, the exposed surface 3a (the surface opposite to the support body 2) comes into contact with the inner wall surface 5a of the cooling water flow passage 5.

[0034] As described above, according to the spacer 1 of this embodiment, when the porous body 3 is attached to the portion of the support 2 corresponding to the convex curved portion 22, the positioning protrusion 11d provided on the mold 10 corresponding to the convex curved portion 22 can be inserted into the through hole 4 provided in the porous body 3 to position the porous body 3 in the mold 10. Furthermore, when the positioning protrusion 11d is inserted into the through hole 4 in a state in which the porous body 3 is curved to a shape that matches the surface shape of the concave curved portion 11b, the porous body 3 is locked by the positioning protrusion 11d. Therefore, when the porous body 3 is attached to the portion of the support 2 corresponding to the convex curved portion 22, a preforming process can be eliminated, and the productivity of the spacer 1 can be improved.

[0035] In the above-described embodiment, the through hole 4 of the porous body 3 is formed at the position of the inflection point closest to the apex 22b of the convex curved portion 22 in the curve corresponding to the surface of the support 2 composed of the concave curved surface 21a and the convex curved surface 22a. In a configuration in which the through hole 4 is disposed near the apex 22b of the convex curved portion 22, when the porous body 3 is attached to the concave curved portion 11b of the lower mold 11, there is a possibility that the through hole 4 will come off the positioning protrusion 11d when a part of the porous body 3 tries to return from a bent state to a flat state. On the other hand, by having the through hole 4 at the position of the above-mentioned inflection point or at a position away from the convex curved portion 22 to the outside of the inflection point, the through hole 4 of the porous body 3 can be more reliably locked by the positioning protrusion 11d even if a part of the porous body 3 tries to return from a bent state to a flat state. In other words, since the porous body 3 can be securely fixed by the molding die 10 due to the force that causes the porous body 3 to return to a flat shape, a gap can be tolerated between the through hole 4 and the positioning protrusion 11d, and the dimensional accuracy of the through hole 4 formed in the porous body 3 can be relaxed.

[0036] Next, based on Fig. 6(a) to (c) and Fig. 7(a) to (d), examples of the positional relationship between the porous body and the positioning protrusion that can be adopted in the molding process of the spacer according to the present invention will be described. Fig. 6(a) to (c) and Fig. 7(a) to (d) are views of the porous body 3 viewed from above (the side opposite to the side where the lower mold 11 is arranged) in the positional relationship between the porous body 3 and the lower mold 11 shown in Fig. 4(a). In each figure, the outer shape of the porous body is shown by a solid line, and the position of the positioning protrusion provided on the lower mold 11 is shown by a black circle. Moreover, the center of the porous body in the left-right direction corresponds to the apex 22b of the convex curved portion 22 of the support 2 (the bottom 11c of the concave curved portion 11b). In each figure, the position of the apex 22b (bottom 11c) is shown by a dashed line. Moreover, in the porous body, a through hole that fits with the positioning protrusion is provided at a position corresponding to the positioning protrusion. That is, in each figure, the through-holes of the porous body overlap with the black dots at the positions where the porous body overlaps. The same reference numerals are used for porous bodies having different shapes but similar functions to the porous body 3 of the spacer 1 described above. Similarly, the same reference numerals are used for through-holes and positioning protrusions having different arrangements but similar functions to the through-holes of the porous body and the positioning protrusions 11d of the lower mold 11 described above.

[0037] In the above embodiment, the number of the positioning protrusions 11d is two, but the number of the positioning protrusions 11d is not particularly limited as long as the positioning protrusions 11d are provided in a plurality of positions sandwiching the apex 22b of the convex curved portion 22 of the support 2. For example, as shown in FIG. 6(a), the positioning protrusions 11d may be arranged at positions corresponding to the four corners of the porous body 3 having a rectangular shape when viewed from the front. Also, as shown in FIG. 6(b), in addition to the two positioning protrusions 11d described in the above embodiment, a positioning protrusion 11d may be further arranged at the intermediate position between the two positioning protrusions 11d (the center of the porous body 3). Even with these configurations, the porous body 3 can be held at the position aligned by the positioning protrusions 11d during insert molding, as in the configuration described in the above embodiment. In the examples shown in FIG. 6(a) and FIG. 6(b), the positioning protrusions 11d are arranged at positions overlapping the porous body 3, and therefore the through holes 4 are provided at the positions in the porous body 3 corresponding to the positioning protrusions 11d.

[0038] In addition, the positioning protrusion 11d may be arranged at a position where it does not overlap with the porous body 3 as long as it can hold the porous body 3 bent along the surface shape of the concave curved portion 11b. For example, in the example shown in FIG. 6(c), one of the positioning protrusions 11d described in the above embodiment is arranged at a position where it does not overlap with the porous body 3, and the edge 31 of the porous body 3 is locked by the peripheral surface 11e of the one positioning protrusion 11d. Even with this configuration, the porous body 3 can be held at the position aligned by the positioning protrusion 11d during insert molding, as in the configuration described in the above embodiment. Note that, in the example shown in FIG. 6(c), for the positioning protrusion 11d arranged at a position where it overlaps with the porous body 3, a through hole 4 is provided at the position of the porous body 3 corresponding to the positioning protrusion 11d.

[0039] Furthermore, in the above examples, the porous body 3 has at least one through hole 4. However, as shown in Fig. 7(a) to Fig. 7(d), a configuration without a through hole 4 may be adopted. That is, as long as the positioning protrusion 11d is positioned in the direction in which an external force is applied to bend the porous body 3, a configuration in which the edges 31 and 32 on both sides of the porous body 3 are engaged with the peripheral surface 11e of the positioning protrusion 11d may be adopted. For example, in the example shown in Fig. 7(a), the positioning protrusions 11d are disposed at positions corresponding to the center of the porous body 3 in the vertical direction, and the edges 31 and 32 on both sides of the porous body 3 are engaged with the peripheral surface 11e of the positioning protrusion 11d. In addition, in the example shown in Fig. 7(b), two positioning protrusions 11d are disposed near the edges 31 and 32 on both sides of the porous body 3 along the vertical direction of the porous body 3, and the edges 31 and 32 on both sides of the porous body 3 are engaged with the peripheral surface 11e of the two positioning protrusions 11d. Furthermore, in the example shown in Figure 7(c), the positioning protrusions 11f are formed in a rectangular shape and are arranged one on each side at positions corresponding to the vertical center of the porous body 3, and the edges 31, 32 on both sides of the porous body 3 are engaged with the peripheral surface 11g of the positioning protrusions 11f.

[0040] Unlike the configuration having the through holes 4, these configurations cannot provide a positioning effect in the vertical direction, i.e., in the direction perpendicular to the direction in which an external force is applied to curve the porous body 3. However, in the molding process in which the resin is insert-molded as described above, a preform is not required for the porous body 3 placed in the molding die 10, and similarly to the spacer 1, the effect of improving the productivity of the spacer can be obtained.

[0041] 7(a) to 7(c), for example, as shown in Fig. 7(d), the edges 33, 34 of the porous body 3 that come into contact with the peripheral surface 11e of the positioning protrusion 11d may be configured as concave curves, and the porous body 3 may be locked to the peripheral surface 11e of the positioning protrusion 11d at the apex of the concave curve. With this configuration, like the configuration with the through hole 4, it is also possible to obtain a positioning effect in the up-down direction, i.e., in the direction perpendicular to the direction in which an external force is applied to curve the porous body 3.

[0042] As described above, according to the present invention, it is possible to provide a spacer and a method for manufacturing a spacer that can eliminate the need for a preforming step and improve productivity.

[0043] The above-mentioned embodiment does not limit the technical scope of the present invention, and various modifications and applications are possible within the scope of the present invention, even if they are not already described. For example, the above-mentioned cellulose sponge may be a fine-grained product with very small bubbles, a small-grained product with small bubbles, or a medium-grained product with medium bubbles. The cellulose sponge is preferably made of cellulose and reinforcing fibers, but is not limited to this and may be made of cellulose alone. The cellulose sponge may be selected from sponges made of cellulose itself, cellulose derivatives in which hydroxyl groups of cellulose remain to an extent that the compressed state can be maintained, such as sponges made of cellulose ethers and cellulose esters, or sponges made of mixtures of these. Furthermore, the porous body 3 may be made of materials other than those mentioned above, as long as it is made of a porous body.

[0044] Furthermore, the form of the engagement portion between the porous body and the positioning protrusion is not limited to that exemplified in the above embodiment, and other configurations can be adopted. Also, a configuration may be adopted in which a through hole is provided in the support body 2 at a location that overlaps with the through hole 4 of the porous body 3, and the through hole communicates with the through hole 4 of the porous body 3. In this case, a recess is provided in a location of the upper mold 13 facing the positioning protrusion 11d, and the positioning protrusion 11d is inserted into the recess when the mold is closed. Also, although a spacer applied to a two-cylinder internal combustion engine has been exemplified as the spacer of the present invention, the present invention is not limited to this and can be applied to internal combustion engines with other numbers of cylinders. [Explanation of symbols]

[0045] 1 Spacer 2 Support 3. Porous bodies 4 Through holes 5 Cooling water flow path 10 mold 11 Lower mold 11b Concave bend 11c bottom 11d Positioning protrusion 21 Arc section 22 Convex curved part (connection part) 22a Convex curved surface 22b Top 40 Cylinder block 41 Cylinder bore

Claims

1. A method for producing a spacer using a molding die, the spacer being disposed in a cooling water flow path formed in a cylinder block of an internal combustion engine so as to surround a cylinder bore, the spacer including a support body made of resin and having a convex curved portion and a porous body attached to a side of the support body including a convex curved surface of the convex curved portion, the mold is provided with a plurality of positioning protrusions sandwiching a bottom portion of a concave curved portion corresponding to a top portion of the convex curved portion of the support; The protrusion length of the positioning protrusion is set to be greater than the thickness of the porous sheet and less than the thickness of the support, A method for manufacturing a spacer, characterized in that the porous body is in a sheet shape, and has no irregularities on either side thereof that can engage with the molding die, and is bent to fit the concave curved portion of the molding die, and then the porous body is placed in the molding die with both end edges of the porous body engaged with the peripheral surfaces of the positioning protrusions, and resin is injected into the molding die to perform insert molding.

2. 2. The method for manufacturing a spacer according to claim 1, A method for manufacturing a spacer, characterized in that the multiple positioning protrusions are provided equally spaced apart from the bottom of the concave curved portion.

3. 3. The method for manufacturing a spacer according to claim 1, further comprising the steps of: A method for manufacturing a spacer, comprising the steps of: placing the porous body in the mold so that the center of the porous body coincides with the bottom of the concave curved portion;

4. The method for manufacturing a spacer according to any one of claims 1 to 3, A method for manufacturing a spacer, characterized in that the positioning protrusions are formed so as to engage with central portions of the edges on both sides of the porous body.

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