Injection molding die, injection molding method, and vehicular member

Abstract

To injection-mold a resin molded body with a desired shape upon an inner surface of a metal cylindrical part.SOLUTION: A movable mold 3 is inserted into a movable space 5 between a stationary mold 2 closely inserted into the inside of a cylindrical part 1 and an inner surface 1a of the cylindrical part 1. A resin P is injected into an injection space 4 in a state in which the injection space 4 provided continuously to the movable space 5 in a circumferential direction is partitioned by a partitioning portion 6 and a blocking wall portion 9 of the movable mold 3. The movable mold 3 is moved in a circumferential direction to a side separating away from the injection space 4. When an engaging portion 8 of the movable mold 3 fully enters the cutout portion 7 of the stationary mold 2, the movable mold 3 and the stationary mold 2 are pulled out of the cylindrical part 1.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an injection mold, an injection molding method, and a vehicle member.

Background Art

[0002] Patent Document 1 discloses a resin injection method in which a metal cylindrical body (cylindrical portion) is set inside a mold, and resin is injected into the inside of the cylindrical portion through injection holes in the wall portion of the cylindrical portion with both ends of the cylindrical portion closed, and a part of the wall portion of the cylindrical portion is bulged to fit the mold by the injection pressure, thereby fixing the resin inside the cylindrical portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above resin injection method, only the inside of the metal cylindrical body (cylindrical portion) is filled with resin, and a resin molded body having a required shape cannot be molded on the inner surface of the metal cylindrical portion.

Means for Solving the Problems

[0005] According to one aspect of the present invention, there is provided an injection mold including a fixed mold that can be tightly inserted into a metal cylindrical portion, and a movable mold that can be inserted into a movable space formed in the fixed mold, wherein an injection space for injecting resin is formed between the fixed mold and the movable mold and the inner surface of the cylindrical portion. The movable space is continuously formed in the inner circumferential direction of the injection space such that the movable mold can move along the inner surface of the cylindrical portion in the inner circumferential direction of the cylindrical portion with the fixed mold inserted into the cylindrical portion. In the movable space, a notch portion that is recessed toward the side opposite to the injection space side is continuously formed in the inner circumferential direction. In the movable mold, a locking portion that can be inserted into the notch portion with the movable mold inserted into the movable space is continuously formed to protrude in the inner circumferential direction of a partition portion that partitions the injection space and the movable space. Further, at a position on the front side in the insertion direction of the movable mold, a closing wall portion that shields an end portion of the injection space on the front side in the insertion direction in the longitudinal direction of the cylindrical portion is continuously formed to protrude in the inner circumferential direction of the partition portion, and a protruding dimension of the closing wall portion in the inner circumferential direction is smaller than a protruding dimension of the locking portion in the inner circumferential direction.

Effects of the Invention

[0006] According to the present invention, resin is injected into the injection space in a state where the end portion of the injection space on the front side in the insertion direction is shielded by the closing wall portion, the movable mold is moved in the movable space in a direction away from the injection space, and the fixed mold and the movable mold are pulled out from the inside of the cylindrical portion, whereby a resin molded body having a required shape can be molded on the inner surface of the metal cylindrical portion.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Mode for Carrying Out the Invention

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that each drawing is schematic and may be different from the actual one. Further, the embodiments of the present invention shown below are examples of devices and methods for embodying the technical idea of the present invention, and the technical idea of the present invention does not specify the structure, arrangement, etc. of the components as follows. The technical idea of the present invention can be variously modified within the technical scope defined by the claims described in the claims.

[0009] FIG. 1 shows a cross-car beam 50 as an example of a vehicle member in which a resin molded body is injection molded on the inner surface of a cylindrical portion by the injection molding method of this embodiment. Generally, the cross-car beam 50 is disposed inside the instrument panel, and both ends in the vehicle width direction are fixed to pillar members or dash panels on the vehicle body side portion. This cross-car beam 50 supports a steering device, an instrument panel, etc., and since rigidity is required, it is molded from a high-rigidity material such as steel or magnesium. The left part of this cross-car beam 50 in the figure is a cylindrical metal cylindrical portion 1. As an example, a resin rib R (see FIG. 3(d)) is integrally formed on the inner surface 1a of the cylindrical portion 1 by injection molding so that a rectangular parallelepiped-shaped other member 51 connected to the right thereof does not rotate when inserted into the cylindrical portion 1.

[0010] The injection mold shown in Fig. 2 has a fixed mold 2 and a movable mold 3. This fixed mold 2 is not a stationary one like the fixed mold in a general mold. Also, the cylindrical portion 1 shown in Fig. 2 is extracted and shown only for the portion into which the mold is inserted. The fixed mold 2 is composed of a metal cylindrical member of a predetermined length that is tightly fitted inside the metal cylindrical portion 1. That is, the outer peripheral surface of this fixed mold 2 has an outer diameter that is approximately the same as or slightly smaller than the inner surface (inner peripheral surface) 1a of the cylindrical portion 1 with a cylindrical shape. In this fixed mold 2, a part of the outer peripheral surface is removed (cut) to the same diameter, and an injection space forming portion 4a and a movable space forming portion 5a are continuously formed in series in the circumferential direction. The injection space forming portion 4a and the movable space forming portion 5a are formed in a square shape when the fixed mold 2 is viewed from the radial direction. In this example, the lower portion of Fig. 2 is the injection space forming portion 4a, and the upper portion is the movable space forming portion 5a. As can be inferred from the figure, when the fixed mold 2 is inserted into the inside of the cylindrical portion 1, an injection space 4 and a movable space 5 that form a part of the wall portion of a concentric cylinder are continuously formed between the inner surface 1a of the cylindrical portion 1. That is, the inner surface (inner peripheral surface) 1a of the cylindrical portion 1 constitutes the outer peripheral surface of the injection space 4 and the movable space 5, and the outer peripheral surface (bottom surface) of the injection space forming portion 4a and the movable space forming portion 5a constitutes the inner peripheral surface of the injection space 4 and the movable space 5. Note that the wall portion of the injection space forming portion 4a formed by recessing the outer peripheral surface of the fixed mold 2 is defined as the injection space wall portion 4b, and similarly, the wall portion of the movable space forming portion 5a is defined as the movable space wall portion 5b.

[0011] The movable mold 3 is composed of a metal member that is a part of a cylindrical body having an outer peripheral surface with a diameter approximately equal to or slightly smaller than the inner surface (inner peripheral surface) 1a of the cylindrical portion 1, and an inner peripheral surface with a diameter approximately equal to or slightly larger than the outer peripheral surfaces (bottom surfaces) of the injection space forming portion 4a and the movable space forming portion 5a. In this example, it has a length equal to the longitudinal dimension of the injection space forming portion 4a and the movable space forming portion 5a. In this movable mold 3, when the movable mold 3 is regarded as a part of the cylindrical body, the central portion in the circumferential direction constitutes a partition portion 6 that separates the injection space 4 and the movable space 5. Therefore, with the movable mold 3 covering the outside of the outer peripheral surface of the movable space forming portion 5a and the fixed mold 2 inserted into the inside of the cylindrical portion 1, the area below the partition portion 6 in the drawing is the injection space 4, and the area above it in the drawing is the movable space 5. Needless to say, the injection space 4 means the space into which the resin P is injected. The injection space 4 in this example is a rectangular space in the shape of a sector in cross-section with a constant dimension (thickness) in the longitudinal direction of the cylindrical portion 1 and in the radial direction. The movable mold 3, which is a part of the cylindrical body covering the outside of the outer peripheral surface of the movable space forming portion 5a, can be moved in the circumferential direction so as to slide along the inner surface (inner peripheral surface) 1a of the cylindrical portion 1 and the outer peripheral surfaces of the injection space forming portion 4a and the movable space forming portion 5a.

[0012] On the movable space wall portion 5b of the fixed mold 2, a notch forming portion 7a that is recessed toward the side opposite to the injection space forming portion 4a is formed continuously in a series in the circumferential direction with the movable space forming portion 5a. In this example, the notch forming portion 7a is formed, for example, at the front end portion in the insertion direction when the movable portion is inserted into the inside of the cylindrical portion 1 in front of the right hand in FIG. 2. This notch forming portion 7a has an outer peripheral surface with the same diameter as the outer peripheral surface of the movable space forming portion 5a, and is formed by recessing the movable space wall portion 5b of the fixed mold 2 into a rectangular shape when viewed from the radial direction. Therefore, when the fixed mold 2 is inserted into the inside of the cylindrical portion 1, a notch portion 7 is formed in which the movable space wall portion 5b of the fixed mold 2 is recessed into a rectangular cross-section by continuously connecting the end portions on the front side in the insertion direction of the movable mold in the movable space 5 in a series in the circumferential direction.

[0013] On one hand, in the movable mold 3, a locking portion 8 that can be inserted into the notch portion 7 in a state where the movable mold 3 is inserted into the movable space 5 is continuously formed to protrude in the circumferential direction from the partition portion 6. This locking portion 8 is also formed by extending a part of the cylindrical body constituting the partition portion 6 in the circumferential direction. In this example, when the movable mold 3 is regarded as a part of the cylindrical body and viewed from the radial direction, the locking portion 8 has a square cross-sectional shape substantially the same as that of the notch forming portion 7a and is formed at the end portion on the front side in the movable mold insertion direction of the partition portion 6. Further, in the movable mold 3, a closing wall portion 9 is continuously formed to protrude in the circumferential direction from the partition portion 6 toward the injection space 4 side at a position on the front side in the movable mold insertion direction. This closing wall portion 9 is also formed by extending a part of the cylindrical body constituting the partition portion 6 in the circumferential direction. In this example, when the movable mold 3 is regarded as a part of the cylindrical body and viewed from the radial direction, the closing wall portion 9 has a square cross-sectional shape and is formed at the end portion on the front side in the movable mold insertion direction of the partition portion 6. As shown in FIG. 2, this closing wall portion 9 shields the end portion on the front side in the movable mold insertion direction of the injection space 4 in the longitudinal direction of the cylindrical portion 1 in a state where the movable mold 3 is on the injection space 4 side and the closing wall portion 9 is in contact with the injection space wall portion 4b of the fixed mold 2 as shown in FIG. 3a. And the protruding dimension of this closing wall portion 9 in the circumferential direction is set smaller than the protruding dimension of the locking portion 8 in the circumferential direction. Also, the recessed dimension of the notch forming portion 7a (notch portion 7) in the circumferential direction is set larger than the protruding dimension of the locking portion 8 in the circumferential direction. That is, even when the locking portion 8 completely enters the notch portion 7, a gap is formed between the circumferential tip portion of the locking portion 8 and the wall portion (notch wall portion) 7b of the notch forming portion 7a.

[0014] When performing injection molding of resin P using this injection mold, as shown in Fig. 2, with the movable mold 3 covering the outer peripheral surface of the injection space forming portion 4a (or the movable space forming portion 5a) of the fixed mold 2, as shown in Fig. 3(a), the fixed mold 2 and the movable mold 3 are inserted into the inside of the cylindrical portion 1. With the closing wall portion 9 of the movable mold 3 in contact with the injection space wall portion 4b of the fixed mold 2 and the end portion on the forward side in the insertion direction of the movable mold of the injection space 4 being closed, as shown in Fig. 3(b), resin P is injected into the injection space 4 to fill the injection space 4 with resin P (resin P is shown by hatching). At this time, since the protruding dimension of the closing wall portion 9 in the circumferential direction is set smaller than the protruding dimension of the locking portion 8 in the circumferential direction, the forward end portion of the locking portion 8 in the insertion direction of the movable mold is caught by the end portion on the front side in the insertion direction of the movable mold of the notch portion 7. As a result, the movement of the movable mold 3 in the forward direction in the insertion direction of the movable mold in the longitudinal direction of the cylindrical portion 1 is restricted. When the resin P filled in the injection space 4 has hardened, as shown in Fig. 3(c), the movable mold 3 is moved within the movable space 5 toward the movable space wall portion 5b side of the fixed mold 2, that is, in the direction away from the injection space 4. Along with this, the locking portion 8 is moved in the circumferential direction and enters into the notch portion 7. At this time, since the recessed dimension of the notch forming portion 7a in the circumferential direction is set larger than the protruding dimension of the locking portion 8 in the circumferential direction, when the locking portion 8 completely enters the notch portion 7, the closing wall portion 9 separates from the resin P (= rib R) injected and hardened in the injection space 4 in the circumferential direction. When the movement of the movable mold 3 toward the movable space wall portion 5b side is completed in this way, as shown in Fig. 3(d), the movable mold 3 and the fixed mold 2 are pulled out from the inside of the cylindrical portion 1.

[0015] As a result, a rectangular resin rib R with a sector-shaped cross-section, which is the same shape as the injection space 4, is formed on the inner surface 1a of the metal cylindrical portion 1 of the cross-car beam 50, which is a vehicle member. When injecting the resin P onto the inner surface 1a of the metal cylindrical portion 1 to form a resin molded body such as the resin rib R, it is advisable to previously form fine irregularities on the inner surface 1a of at least the portion of the injection space 4 of the resin P by caustic treatment or the like. If the inner surface 1a of the metal cylindrical portion 1 is smooth, the injection-cured resin P is difficult to adhere. Therefore, by previously performing uneven processing on the inner surface 1a of the metal cylindrical portion 1 where at least the resin molded body R is to be formed, the injection-cured resin P is likely to adhere. Also, as described above, the movement of the movable mold 3 in the forward direction of the insertion direction of the movable mold is restricted by the locking portion 8 being caught by the notch portion 7. However, for example, the circumferential movement of the movable mold 3 during resin injection cannot be restricted. Therefore, at least during resin injection, it is necessary to fix the movable mold 3 and the fixed mold 2 with an actuator or the like so that they do not move.

[0016] In the first modification of the injection mold shown in FIG. 4, a plurality of movable spaces 5 in FIG. 3 are formed at a plurality of locations in the circumferential direction of the fixed mold 2, four locations in the example of the figure, and the movable mold 3 is inserted into each movable space 5. Each movable space 5 is accompanied by an injection space 4. Therefore, when injecting the resin P into the metal cylindrical portion 1 of the cross-car beam 50 in FIG. 1 using this injection mold, as shown in FIG. 5, it becomes possible to simultaneously form four resin ribs R in the circumferential direction of the inner surface 1a of the metal cylindrical portion 1. In the illustrated example, the movable spaces 5, that is, the injection spaces 4, are provided at equal intervals in the circumferential direction of the fixed mold 2, but the arrangement of the injection spaces 4 is arbitrary.

[0017] In the second modification example of the injection mold shown in Fig. 6, a plurality of the notch forming portions 7a (notch portions 7) and locking portions 8 in Fig. 2 or Fig. 3 are provided at three locations in the longitudinal direction of the fixed mold 2 with respect to one movable space forming portion 5a (movable space 5) and one movable mold 3. Similar to the above, when injecting the resin P into the injection space 4, all the locking portions 8 are caught by the notch portions 7, and the movement of the movable mold 3 in the forward direction of the movable mold insertion direction (longitudinal direction of the cylindrical portion 1) is restricted. Also, when the movable mold 3 moves in the direction away from the injection space 4, all the locking portions 8 enter the inside of the notch portions 7. In this example, all the notch forming portions 7a (notch portions 7) and the locking portions 8 have the same shape. However, as can be inferred from the above, if the locking portions 8 fit tightly inside the notch portions 7, the notch portions 7 and the locking portions 8 at different locations may have different shapes from those at other locations. Also, in this example, another closing wall portion 9 is provided as an engaging closing wall portion 9a at a position ahead in the movable mold insertion direction of the injection space 4, and in the injection space wall portion 4b of the fixed mold 2, a receiving recess 10 capable of tightly accommodating this engaging closing wall portion 9a is recessed in the circumferential direction continuously with the movable space 5. Therefore, when moving the movable mold 3 toward the injection space 4 side and injecting the resin P into the injection space 4, the engaging closing wall portion 9a fits tightly into the receiving recess 10, and thereby the movement of the movable mold 3 in the forward direction of the movable mold insertion direction (= longitudinal direction of the cylindrical portion 1) is also restricted.

[0018] In the third modification of the injection mold shown in FIG. 7, the injection space forming portion 4a of the stationary mold 2 that forms the injection space 4 is recessed in a direction intersecting the inner surface 1a of the cylindrical portion 1, that is, in the radial direction of the cylindrical stationary mold 2, more than the movable space forming portion 5a that forms the movable space 5. In this example, at the front end portion of the injection space forming portion 4a in the movable mold insertion direction, the injection space forming portion 4a has the same depth as the movable space forming portion 5a in the radial direction of the stationary mold 2, and at the rear end portion in the movable mold insertion direction, it is deeper in the radial direction of the stationary mold 2, and its bottom is uniformly inclined. Therefore, as shown in FIG. 8, the resin rib R formed by injecting the resin P into the injection space 4 formed by this injection mold has a rib with a high front side and a low rear side in the longitudinal direction of the cylindrical portion 1 and an inclined protruding end face. In such a resin rib R with a high front side, for example, the effect of preventing the rotation of other members 51 inserted into the cylindrical portion 1 is improved. As can be inferred from this example, by making the injection space forming portion 4a of the stationary mold 2 more recessed than the movable space forming portion 5a, most of the injection space 4 for forming the resin molded body R can be constituted by the injection space forming portion 4a of the stationary mold 2. In that case, the movable mold 3 can be regarded as closing a part of the rear end portion (front end portion in the movable mold insertion direction) of the injection space 4 and a part of the movable space side end portion.

[0019] In the fourth modification example of the injection mold shown in Fig. 9, as shown in Fig. 9(a), the notch contact surface 7b that contacts the locking portion 8 of the notch forming portion 7a and the locking contact surface 8b of the locking portion 8 that contacts the notch forming portion 7a of the notch forming portion 7a (notch portion 7) on the front side in the movable mold insertion direction are inclined with respect to the longitudinal direction of the fixed mold 2, that is, the longitudinal direction of the cylindrical portion 1 so that the notch forming portion 7a becomes wider. Further, the closing surface 9b on the injection space 4 side of the closing wall portion 9 is inclined with respect to the longitudinal direction of the movable mold 3, that is, the longitudinal direction of the cylindrical portion 1 so that the injection space 4 on the front side in the movable mold insertion direction becomes wider. By inclining the notch forming portion 7a, the locking portion 8, and the closing wall portion 9 with respect to the longitudinal direction of the fixed mold 2, that is, the movable mold insertion direction, so that the front side in the movable mold insertion direction of the notch portion 7 and the injection space 4 becomes wider, by simply pulling the movable mold 3 toward the front side in the insertion direction, as shown in Figs. 9(b) and 9(c), the movable mold 3 is moved to the movable space 5 side (movable space wall portion 5b side), and further, as shown in Fig. 9(d), the movable mold 3 can be pulled out of the movable space 5 as it is.

[0020] Thus, in this embodiment, the resin P is injected into the injection space 4 in a state where the end portion on the front side in the movable mold insertion direction of the injection space 4 of the fixed mold 2 is shielded by the closing wall portion 9 of the movable mold 3, and then the movable mold 3 is moved in the movable space 5 in a direction away from the injection space 4, and the fixed mold 2 and the movable mold 3 are pulled out from the inside of the cylindrical portion 1, whereby a resin molded body R having a required shape can be molded on the inner surface 1a of the metal cylindrical portion 1. At that time, since the protruding dimension of the closing wall portion 9 in the circumferential direction is set smaller than the protruding dimension of the locking portion 8 in the circumferential direction, when the resin P is injected into the injection space 4, the locking portion 8 is caught by the notch portion 7 and the movement of the movable mold 3 toward the front side in the insertion direction, that is, the back side of the cylindrical portion 1 is restricted.

[0021] Further, a plurality of movable spaces 5 are formed at a plurality of locations in the circumferential direction of the fixed mold 2, and the movable mold 3 is inserted into each movable space 5 and used, whereby a plurality of resin molded bodies R can be simultaneously formed on the inner surface 1a of the metal cylindrical portion 1. In addition, by providing a plurality of notches 7 and locking portions 8 for one movable space 5 and one movable mold 3, the forward side in the insertion direction of the movable mold 3 when injecting the resin P into the injection space 4, that is, the movement toward the inner side of the cylindrical portion 1 is more reliably restricted. Further, since a housing recess 10 capable of housing the engagement closing wall portion 9a is continuously recessed in the circumferential direction in the movable space 5 at a position ahead in the insertion direction of the movable mold in the injection space 4, the forward side in the insertion direction of the movable mold 3 when injecting the resin P into the injection space 4, that is, the movement toward the inner side of the cylindrical portion 1 is more reliably restricted, and the forward side in the insertion direction of the injection space 4 can be reliably closed.

[0022] In addition, since the injection space forming portion 4a of the fixed mold 2 forming the injection space 4 is recessed in a direction intersecting with the inner surface 1a of the cylindrical portion 1, that is, in the radial direction of the fixed mold 2, from the movable space forming portion 5a of the fixed mold 2 forming the movable space 5, a resin molded body R having a large height can be formed inside the cylindrical portion 1 without unnecessarily increasing the thickness of the movable mold 3. Further, since the notch contact surface 7b that contacts the locking portion 8 of the notch portion 7 and the locking contact surface 8b that contacts the notch portion 7 of the locking portion 8 are inclined with respect to the longitudinal direction of the cylindrical portion 1 so that the notch portion 7 on the front side in the insertion direction of the movable mold becomes wider, the movable mold 3 is moved to the movable space 5 side (movable space wall portion 5b side) by simply pulling the movable mold 3 forward in the insertion direction. Further, since the closing surface 9b on the injection space 4 side of the closing wall portion 9 is inclined with respect to the longitudinal direction of the cylindrical portion 1 so that the injection space 4 on the front side in the insertion direction of the movable mold becomes wider, after the resin P injected into the injection space 4 is cured, the movable mold 3 is moved to the movable space 5 side (movable space wall portion 5b side) by simply pulling the movable mold 3 forward in the insertion direction.

[0023] In addition, by previously performing uneven processing on the inner surface 1a of the cylindrical portion 1 in the injection space 4, the resin molded body R formed on the inner surface 1a can be reliably fixed. In addition, by forming a resin rib R on the inner surface 1a of the cylindrical portion 1 of the cross beam 50, the rotation of another member 51 inserted into the cylindrical portion 1 can be restricted.

[0024] The injection mold, injection molding method, and vehicle member according to the embodiment have been described above. However, the present invention is not limited to the configurations described in the above embodiment, and various modifications are possible within the scope of the gist of the present invention. For example, in the above embodiment, only the cylindrical tubular portion 1 has been described. However, the cross-sectional shape of the metallic tubular portion 1 that is the subject of the present invention is not limited to this. Since the movable mold 3 needs to be movable along the inner surface 1a of the tubular portion 1 in the injection mold of the present invention, as long as at least the inner surface 1a of the tubular portion 1 where the movable mold 3 moves has an arcuate cross-sectional shape or a planar shape, that is, a shape with a constant cross-sectional curvature, the cross-sectional shape of the remaining portion of the tubular portion 1 can be any shape. Similarly, for the fixed mold 2 and the movable mold 3, it is only necessary that there is no gap through which the resin P injected between the circumferential end of the injection space 4, that is, between the injection space wall portion 4b and the partition portion 6 and the inner surface 1a of the tubular portion 1, can leak. The outer shape of the remaining portion of the fixed mold 2 only needs to be insertable tightly into the inside of the tubular portion 1, and the movable mold 3 only needs to be shaped such that the outer surface of the partition portion 6, particularly the end on the injection space 4 side, is in close contact with the inner surface 1a of the tubular portion 1 by the movable space 5.

Description of Reference Numerals

[0025] 1... Tubular portion, 1a... Inner surface (inner circumferential surface), 2... Fixed mold, 3... Movable mold, 4... Injection space, 4a... Injection space forming portion, 5... Movable space, 5a... Movable space forming portion, 6... Partition portion, 7... Notch portion, 7b... Notch contact surface, 8... Locking portion, 8b... Locking contact surface, 9... Closing wall portion, 9a... Engaging closing wall portion, 9b... Closing surface, 10... Accommodating recess, 50... Cross beam, P... Resin, R... Rib (resin molded body)

Claims

1. An injection mold comprising a fixed mold that can be tightly inserted into the inside of a metal cylindrical part, and a movable mold that can be inserted into a movable space formed in the fixed mold, wherein an injection space for injecting resin is formed between the fixed mold and the movable mold and the inner surface of the cylindrical part, the movable space is continuously formed in the inner circumferential direction of the injection space so that the movable mold can move in the inner circumferential direction of the cylindrical part along the inner surface of the cylindrical part with the fixed mold inserted into the inside of the cylindrical part, a notch portion that is recessed toward the side opposite to the injection space side is continuously formed in the inner circumferential direction in the movable space, in the movable mold, a locking portion that can be inserted into the notch portion in a state of being inserted into the movable space is continuously formed to protrude in the inner circumferential direction of a partition portion that partitions the injection space and the movable space, and at a position on the front side in the insertion direction of the movable mold, a closing wall portion that shields an end portion on the front side in the insertion direction of the injection space in the longitudinal direction of the cylindrical part is continuously formed to protrude in the inner circumferential direction of the partition portion, The injection mold is characterized in that a protruding dimension of the closing wall portion in the inner circumferential direction is smaller than a protruding dimension of the locking portion in the inner circumferential direction.

2. The injection mold according to claim 1, wherein the movable spaces are formed at a plurality of locations in the inner circumferential direction of the fixed mold, and the movable mold is inserted into each movable space.

3. The injection mold according to claim 1, wherein a plurality of the notch portions and the locking portions are provided for one movable space and one movable mold.

4. The injection mold according to claim 1, wherein a housing recess for housing the closing wall portion is continuously recessed in the inner circumferential direction in the movable space at a position on the front side in the insertion direction of the injection space.

5. The injection mold according to claim 1, wherein an injection space forming portion of the fixed mold that forms the injection space is recessed in a direction intersecting with the inner surface of the cylindrical part more than a movable space forming portion of the fixed mold that forms the movable space.

6. The injection mold according to claim 1, wherein a notch contact surface of the notch portion that contacts the locking portion and a locking contact surface of the locking portion that contacts the notch portion of the notch portion are inclined with respect to the longitudinal direction of the cylindrical part so that the notch portion on the front side in the insertion direction becomes wider.

7. The injection mold according to claim 1, wherein a closing surface of the closing wall portion on the injection space side is inclined with respect to the longitudinal direction of the cylindrical portion so that the injection space on the front side in the insertion direction becomes wider.

8. An injection molding method using the injection mold according to any one of claims 1 to 7, wherein resin is injected into the injection space in a state where an end portion on the front side in the insertion direction of the injection space is shielded by the closing wall portion, the movable mold is moved in the movable space in a direction away from the injection space, and the fixed mold and the movable mold are pulled out from inside the cylindrical portion.

9. The injection molding method according to claim 8, wherein uneven processing is previously performed on the inner surface of the cylindrical portion in the injection space.

10. A vehicle member, wherein a resin rib is formed on the inner surface of a cylindrical portion of a cross beam by the injection molding method according to claim 8.

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