Actuator, method for manufacturing actuator housing, and core for manufacturing

Abstract

In the actuator housing, a mounting groove for mounting a mounting part of a protective cover is formed in the inner peripheral surface of an output hole, so that the mounting part can be protected from external impact, and the mounting groove can be formed simultaneously when the actuator housing is molded from resin. A plurality of first protruding walls which protrude inward in the radial direction and are arranged in the circumferential direction of the output hole with a first gap therebetween are formed at the outer end of the output hole, and a plurality of second protruding walls which protrude inward in the radial direction and are arranged in the circumferential direction of the output hole with a second gap therebetween are formed at the inner end of the output hole. The first protruding wall and the second protruding wall are disposed so as not to overlap each other, and a mounting groove for mounting the mounting part of the protective cover is defined on the inner peripheral surface of the output hole by the first protruding wall and the second protruding wall.

Description

Technical Field

[0001] The present invention relates to an actuator, a method for manufacturing the actuator housing, and a core for manufacturing the actuator. For the actuator, an actuator mechanism is housed in a resin actuator housing, and an output component of the actuator mechanism is arranged in a manner that passes through an output hole of the actuator housing, and a protective cover covering the outer portion of the output component protruding outside the output hole is installed on the actuator housing. Background Art

[0002] An actuator as disclosed in Patent Document 1 is known.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: WO2019 / 187362 Summary of the invention

[0006] Technical problem to be solved by the invention

[0007] However, in the actuator described in Patent Document 1, when the protective cover is mounted on the actuator housing, a mounting groove surrounding the output hole is formed on the outer peripheral surface of the annular protruding wall protruding from the outer side surface of the actuator housing, and the mounting portion of the protective cover is mounted on the mounting groove. In this case, since the mounting portion of the protective cover is exposed to the outside of the actuator housing, the mounting portion may be detached from the mounting groove when the mounting portion is subjected to some kind of impact.

[0008] The present invention is completed in view of the above situation, and its purpose is to provide an actuator, a manufacturing method of the actuator housing, and a manufacturing core. For this actuator, a mounting groove for mounting a mounting portion of a protective cover is formed on the inner circumferential surface of the output hole, which can protect the mounting portion from external impact, and the mounting groove can be formed at the same time when the actuator housing is molded using resin.

[0009] Technical solutions for solving technical problems

[0010] In order to achieve the above-mentioned purpose, the present invention provides an actuator according to a first aspect, characterized in that:

[0011] The actuator includes an actuator case made of resin and an actuator mechanism accommodated in the actuator case.

[0012] The output member of the actuator mechanism is arranged in a manner penetrating the output hole of the actuator housing.

[0013] A protective cover is mounted on the actuator housing, and the protective cover covers the outer portion of the output component protruding out of the output hole.

[0014] A plurality of first protruding walls are formed on the outer end side of the output hole, the plurality of first protruding walls protrude radially inward from the inner circumferential surface of the output hole and are arranged with first gaps therebetween in the circumferential direction of the output hole.

[0015] In addition, a plurality of second protruding walls are formed on the inner end side of the output hole, the plurality of second protruding walls protrude radially inward from the inner circumferential surface of the output hole and are arranged with second gaps therebetween in the circumferential direction of the output hole.

[0016] The first protruding wall and the second protruding wall are arranged so as not to overlap each other when the output hole is viewed from above.

[0017] The first protruding wall and the second protruding wall define an installation groove on the inner peripheral surface of the output hole for installing the installation portion of the protection cover.

[0018] It should be noted that the output member corresponds to the output screw 19 in the embodiment of the present invention described later.

[0019] In addition, a second aspect of the present invention is characterized in that, in addition to the first aspect, a width of the first gap between the first protruding walls is set to be larger than a length of the second protruding wall along the circumferential direction of the output hole.

[0020] Furthermore, the third aspect of the present invention is based on the first aspect and is characterized in that the protruding height of the second protrusion is set to be larger than the protruding height of the first protrusion, and the second protrusion supports the mounting part during the installation process of the mounting part into the mounting groove.

[0021] Furthermore, a fourth aspect of the present invention is based on the first aspect, wherein a length of the first protruding wall along the circumferential direction of the output hole is set to be smaller than a length of the second protruding wall along the circumferential direction of the output hole.

[0022] Furthermore, according to a fifth aspect of the present invention, based on any one of the first to fourth aspects, a reinforcing member is embedded in the mounting portion.

[0023] In addition, a sixth aspect of the present invention provides a method for manufacturing an actuator housing, characterized in that:

[0024] The actuator housing has:

[0025] An output hole is arranged in a manner for the output component to pass through; a mounting groove is installed on a mounting portion of a protective cover, the protective cover covers the outer portion of the output component protruding outside the output hole, and the mounting groove is divided on the inner circumferential surface of the output hole by a plurality of first protruding walls and a plurality of second protruding walls, the plurality of first protruding walls are protruding inwardly in the radial direction at the outer end of the output hole, and are arranged with a first gap in the circumferential direction of the output hole, and the plurality of second protruding walls are protruding inwardly in the radial direction at the inner end of the output hole, and are arranged with a second gap in the circumferential direction of the output hole,

[0026] The first protruding wall and the second protruding wall are arranged so as not to overlap each other when the output hole is viewed from above.

[0027] In the step of molding the actuator housing with resin,

[0028] A core is provided to form the inner peripheral surface of the output hole, wherein the core is configured so that a first core half located on the outer end side of the output hole and a second core half located on the inner end side of the output hole can be axially separated and fitted together.

[0029] A first recess and a second recess are defined between the first core half and the second core half to form the first protruding wall and the second protruding wall, respectively.

[0030] Resin is injected into a cavity that is defined by the first core half body, the second core half body, and an outer mold that forms an outer surface of the actuator housing and includes the first recessed portion and the second recessed portion.

[0031] Furthermore, the seventh aspect of the present invention provides a core used in the method for manufacturing the actuator housing according to the sixth aspect, characterized in that:

[0032] The first core half body is composed of a hollow cylindrical portion forming the inner peripheral surface of the mounting groove and a top wall portion connected to the outer end of the hollow cylindrical portion.

[0033] The top wall portion is provided with a groove portion corresponding to the first protruding wall,

[0034] The hollow cylindrical portion is provided with a cutout corresponding to the second gap between the second protruding walls.

[0035] The second core half body is composed of a first cylindrical portion that can be inserted and removed into the inner circumferential surface of the hollow cylindrical portion and a second cylindrical portion that is connected to the first cylindrical portion and has a larger diameter than the first cylindrical portion.

[0036] A protrusion is provided on the first cylindrical portion, and the protrusion engages with the cutout and cooperates with the groove to divide the first recessed portion.

[0037] The second recessed portion is defined by the front end surface of the hollow cylindrical portion, the protrusion, and a step portion between the first cylindrical portion and the second cylindrical portion.

[0038] According to the first aspect of the present invention, a plurality of first protrusions are formed at the outer end of the output hole, which protrude inwardly in the radial direction and are arranged with gaps in the circumferential direction of the output hole. In addition, a plurality of second protrusions are formed at the inner end of the output hole, which protrude inwardly in the radial direction and are arranged with gaps in the circumferential direction of the output hole. The first protrusions and the second protrusions are arranged so as not to overlap each other when the output hole is viewed from above, and a mounting portion for mounting a protective cover is divided between the first protrusions and the second protrusions. Therefore, when the actuator housing is formed using resin, the first protrusions and the second protrusions are formed using a core divided in the axial direction in the output hole, thereby dividing the mounting groove. Therefore, after the actuator housing is formed, additional processing for forming the mounting groove is not required, which can help reduce manufacturing costs. In addition, the mounting portion of the protective cover mounted on the mounting groove in the output hole can be protected from external impact and prevented from detaching from the mounting groove.

[0039] According to the second aspect of the present invention, since the width of the first gap between the first protrusions is set to be larger than the circumferential length of the second protrusion along the output hole, when the actuator housing is molded using resin, the first protrusion and the second protrusion can be easily and reliably formed by a core divided axially in the output hole.

[0040] According to the third aspect of the present invention, because the protruding height of the second protrusion is set to be larger than the protruding height of the first protrusion, the mounting part is supported by the second protrusion during the installation of the mounting part into the mounting groove, so the mounting part can be easily pressed into the mounting groove, and the second protrusion can prevent the mounting part from moving forward excessively.

[0041] According to the fourth aspect of the present invention, by setting the length of the first protrusion along the circumference of the output hole to be smaller than the length of the second protrusion along the circumference of the output hole, the installation portion can be pressed into the installation groove more easily. In addition, after the installation, the first protrusion can prevent the installation portion from detaching from the installation groove.

[0042] According to the fifth aspect of the present invention, by burying the reinforcing member in the mounting portion, the force of press-fitting the mounting portion into the mounting groove can be effectively increased, thereby stabilizing the mounting state of the mounting portion in the mounting groove.

[0043] According to the sixth aspect of the present invention, when molding the actuator housing, the output hole having the mounting groove can be formed using the first core and the second core. Therefore, after molding, an additional process for obtaining the mounting groove is not required, which can help reduce manufacturing costs.

[0044] According to the seventh aspect of the present invention, when the actuator housing is molded, the output hole having the mounting groove can be reliably formed using the first core and the second core. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a longitudinal sectional side view of the actuator according to the embodiment of the present invention.

[0046] Figure 2 yes Figure 1 2 enlarged views of the parts (the output screw is not shown).

[0047] Figure 3 yes Figure 2 3-3 line section view.

[0048] Figure 4 This is a cross-sectional view of a product and a molding die showing a molding method for the periphery of the output hole of the actuator housing.

[0049] Figure 5 It is expressed in decomposed state Figure 4 Cross-sectional view of the product and core.

[0050] Figure 6 and Figure 4 Correspondingly, the cross-sectional area is set as a different cross-sectional view.

[0051] Figure 7 It is expressed in decomposed state Figure 6 Cross-sectional view of the product and core.

[0052] Figure 8 It is a three-dimensional diagram showing the above-mentioned product and core in an exploded state. DETAILED DESCRIPTION

[0053] First, refer to the attached Figure 1 Embodiments of the present invention will be described.

[0054] The actuator A is composed of an actuator case 10 and an actuator mechanism 11 accommodated in the actuator case 10. In the actuator A, the extension direction of an output screw 19 described later from the actuator case 10 is defined as the front direction, and the opposite direction thereof is defined as the rear direction.

[0055] The actuator housing 10 includes a cylindrical motor housing portion 10a, a cylindrical output housing portion 10b arranged parallel to and adjacent to the motor housing portion 10a, and a gear housing portion 10c connecting the rear end portion of the motor housing portion 10a with the middle portion of the output housing portion, and an output hole 15 is provided at the front end portion of the output housing portion 10b.

[0056] The actuator case 10 is divided into a case body 10A at the front half and a case cover 10B at the rear half so as to enable assembly and disassembly of the actuator mechanism 11. The case body 10A and the case cover 10B are injection-molded by resin.

[0057] The actuator mechanism 11 includes a motor 12 housed in a motor housing portion 10a; an output screw 19 configured to protrude from the output housing portion 10b through the output hole 15 to the outside; a reduction gear set 13 housed in a gear housing portion 10c and an output housing portion 10b, which reduces the rotation of a rotor shaft 10a of the motor 12 and transmits it to a final gear 14; and a motion conversion mechanism 16 housed in the output housing portion 10b, which converts the rotational motion of the final gear 14 into an axial motion and transmits it to the output screw 19.

[0058] The motion conversion mechanism 16 includes a rotating nut 18 supported by the output housing portion 10b via a bearing 17 so as to be rotatable and axially immovable, and an external thread 19a of the output screw 19 screwed with the internal thread 18a of the rotating nut 18. The rotating nut 18 is connected to the final gear 14 by a large diameter cylindrical portion 20 integrally provided at the rear end thereof, and can rotate together with the final gear 14, but cannot move in the axial direction. In addition, a key 21 protruding in the diameter direction is formed at the rear end of the output screw 19, and a key groove 22 slidably engaged with the key 21 is provided on the output housing portion 10b. Therefore, the output screw 19 can move in the axial direction thereof, but cannot rotate.

[0059] The front end portion of the output screw 19 that protrudes out of the output hole 15 is connected to a parking brake mechanism (not shown) of a drum brake via a cable 23 .

[0060] A plurality of disc springs 24 which are compressed by the forward movement of the key 21 are accommodated in the large-diameter cylindrical portion 20 of the rotating nut 18 .

[0061] Furthermore, by the operation of the motor 12, the rotational power of the rotor shaft 10a is decelerated and transmitted to the final gear 14 via the gear group 13. When the rotating nut 18 rotates together with the final gear 14, the rotating internal thread 18a of the rotating nut 18 applies a thrust to the output screw 19 via the external thread 19a to make it move forward and backward according to the positive and negative rotation direction. When the output screw 19 is displaced backward by the thrust, the cable 23 is pulled, and the parking brake mechanism (not shown) is put into a braking state. In addition, when the output screw 19 is displaced forward, the cable 23 is relaxed, and the parking brake mechanism is put into a brake release state. In this brake release state, the disc spring 24 is compressed between the rotating nut 18 and the key 21, and the backlash between the internal thread 18a and the external thread 19a is removed by its reaction force.

[0062] In order to seal the output hole 15 of the output housing portion 10 b to prevent dust and water, a bellows-type protective cover 25 made of elastic material is attached to the output housing portion 10 b so as to cover the outer portion of the output screw 19 .

[0063] In detail, Figure 1 and Figure 2 As shown, the protective cover 25 has a first mounting portion 26 with a large diameter at one end thereof, and a second mounting portion 27 with a small diameter at the other end. A metal reinforcement member 28 is embedded in the first mounting portion 26 with a large diameter, and the first mounting portion 26 is press-fitted and mounted in a mounting groove 30 formed on the inner peripheral surface of the output hole 15, and the second mounting portion 27 with a small diameter is mounted in an outer peripheral groove 31 at the front end of the output screw 19. The first mounting portion 26 is an example of a mounting portion of the present invention.

[0064] according to Figure 2 , Figure 3 , Figure 5 and Figure 8 , the structure of the above-mentioned mounting groove 30 is described.

[0065] First, on the inner circumferential surface of the output hole 15, a plurality of (four in the example shown) first protruding walls 33 are formed on the outer end side along the circumferential direction of the output hole 15 with first gaps 35 therebetween, and second protruding walls 34 of the same number as the first protruding walls 33 are formed on the inner end side along the circumferential direction of the output hole 15 with second gaps 36 therebetween. At this time, these first and second protruding walls 33 and 34 are arranged so as not to overlap each other when the output hole 15 is viewed from above (see FIG. 1 ). Figure 3 ). Furthermore, the first and second protruding walls 33 and 34 are used to define the mounting groove 30 on the inner circumferential surface of the output hole 15 .

[0066] The width of the first gap 35 between the first protruding walls 33 is set to be larger than the length s2 of the second protruding wall 34 along the circumferential direction of the output hole 15. This means that the width of the second gap 36 between the second protruding walls 34 is set to be larger than the length s1 of the first protruding wall 33 along the circumferential direction of the output hole 15.

[0067] Furthermore, the protrusion height t2 of each second protrusion wall 34 from the inner circumferential surface of the output hole 15 (i.e., the bottom surface of the mounting groove 30) is set to be larger than the protrusion height t1 of each first protrusion wall 33 from the inner circumferential surface of the output hole 15. In other words, the diameter of the imaginary circle in contact with the front end surfaces of all the second protrusion walls 34 is set to be larger than the diameter of the imaginary circle in contact with the front end surfaces of all the first protrusion walls 33.

[0068] Furthermore, a length s1 of each first protruding wall 33 along the circumferential direction of the output hole 15 is set to be smaller than a length s2 of each second protruding wall 34 along the circumferential direction of the output hole 15 .

[0069] In addition, the inner diameter D2 of the mounting groove 30 is set to be slightly smaller than the outer diameter D1 of the first mounting portion 26 .

[0070] A tapered press-fitting guide surface 40 is formed at the outer edge of the output hole 15 so as to be continuous with the outer end surface of the first protruding wall 33 .

[0071] Next, the operation of this embodiment will be described.

[0072] In order to install the first mounting portion 26 of the protective cover 25 in the mounting groove 30 of the output housing portion 10b, when the first mounting portion 26 is pressed toward the tapered press-in guide surface 40 of the output housing portion 10b, the first mounting portion 26 enters the mounting groove 30 while being compressed in the diameter-reducing direction by the first protruding wall 33, and is supported by the second protruding wall 34 to limit excessive forward movement, and is prevented from escaping from the mounting groove 30 by the first protruding wall 33. In addition, since the first mounting portion 26 is provided with a set load in the diameter-reducing direction through its bottom surface in the mounting groove 30, it is in a stable mounting state without shaking. In particular, since the reinforcing member 28 is embedded in the first mounting portion 26, the press-in reaction force of the first mounting portion 26 into the mounting groove 30 can be effectively increased, and the mounting state of the first mounting portion 26 into the mounting groove 30 can be made more stable.

[0073] However, the plurality of first protruding walls and the plurality of second protruding walls 33 and 34 that define the mounting groove 30 on the inner circumferential surface of the output hole 15 are arranged so as not to overlap each other when the output hole 15 is viewed from above, so that when the housing body 10A is formed as described later, it is possible to use a core that is divided into two parts in the axial direction to form the housing body 10A, and no special additional process is required to form the mounting groove 30, which can help reduce manufacturing costs. In addition, the first mounting portion 26 mounted on the mounting groove 30 in the output hole 15 can be protected from external impacts and prevented from being detached from the mounting groove 30.

[0074] Next, through Figures 4 to 8 A method of injection molding the case body 10A, particularly the front portion of the output case portion 10 b having the output hole 15 , the first and second protruding walls 33 , 34 , and the mounting groove 30 , using resin will be described.

[0075] When the housing body 10A is formed, an outer mold 41 (see Figure 4 ) and the core 42 forming the inner peripheral surface of the output hole 15 (refer to Figure 5 , Figure 7 , Figure 8 ).

[0076] The outer mold 41 is composed of a first outer mold half 41a and a second outer mold half 41b which are overlapped and can be separated by a parting surface 43 passing through the central axis Y of the output hole 15. In addition, the core 42 is configured so that the first core half 42a located on the outer end side of the output hole 15 and the second core half 42b located on the inner end side of the output hole 15 can be axially separated and fitted. The first and second recessed portions 45 and 46 forming the first and second projecting walls 33 and 34 are defined between the first and second core half 42a and 42b as follows.

[0077] The first core half body 42a is composed of a hollow cylindrical portion 47 forming the inner peripheral surface of the mounting groove 30 and a top wall portion 48 connected to the outer end of the hollow cylindrical portion 47. The top wall portion 48 is provided with a groove portion 49 corresponding to the first protruding wall 33 (see Figure 5 ). In addition, the outer end of the top wall portion 48 is provided with a flange 50 having a triangular cross section forming the above-mentioned press-fitting guide surface 40. On the other hand, the hollow cylindrical portion 47 is provided with a cutout 51 corresponding to the second gap 36 between the above-mentioned second protruding walls 34.

[0078] The second core half 42b is composed of a first cylindrical portion 52 that can be inserted and removed into the inner circumference of the hollow cylindrical portion 47 and a second cylindrical portion 53 that is connected to the first cylindrical portion 52 and has a larger diameter than the first cylindrical portion 52. In addition, a protrusion 54 is provided on the first cylindrical portion 52 (see Figure 8 ), the protrusion 54 engages with the cutout 51 and cooperates with the groove 49 to divide the first recess 45. Furthermore, the second recess 46 is divided by the front end surface of the hollow cylindrical portion 47, the protrusion 54, and the step 55 between the first cylindrical portion and the second cylindrical portion 52, 53.

[0079] Furthermore, when the first outer mold half and the second outer mold half 41a, 41b are overlapped and molded at the parting surface 43, and the first core half and the second core half 42a, 42b are fitted together inside, a cavity 56 including the first and second recesses 45, 46 is defined between the first outer mold half and the second outer mold half 41a, 41b and the first and second core half 42a, 42b, and a resin is injected into the cavity 56, so that the first and second protruding walls 33, 34 defining the mounting groove 30 and the press-fitting guide surface 40 can be formed simultaneously with the molding of the case body 10A. Therefore, after the case body 10A is molded, an additional process for forming the mounting groove 30 is not required, thereby reducing the manufacturing cost.

[0080] As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, Various design changes can be made without departing from this invention described in a claim.

[0081] This application claims the benefit of priority based on Japanese Patent Application No. 2022-114949 filed on July 19, 2022. The entire disclosure of Japanese Patent Application No. 2022-114949 filed on July 19, 2022 including specification, claims, drawings, and abstract is incorporated herein by reference in its entirety.

[0082] Description of Reference Numerals

[0083] A...Actuator

[0084] s1・・・The length of the first protruding wall

[0085] s2・・・The length of the second protruding wall

[0086] t1・・・Height of the first protruding wall

[0087] t2・・・The height of the second protruding wall

[0088] 10・・・Actuator housing

[0089] 11・・・Actuator mechanism

[0090] 15. Output port

[0091] 19. Output parts (output screw)

[0092] 25・・・Protective cover

[0093] 26・・・As the first mounting part

[0094] 28・・・Reinforcement parts

[0095] 30・・・Mounting slot

[0096] 33. First protruding wall

[0097] 34・・・Second protruding wall

[0098] 35・・・First gap

[0099] 36・・・The second gap

[0100] 41・・・External model

[0101] 41a・・・First outer mold half

[0102] 41b・・・Second outer mold half

[0103] 42・・・Core

[0104] 42a・・・First core half

[0105] 42b・・・Second core half

[0106] 45・・・First recess

[0107] 46・・・Second recess

[0108] 47...Hollow cylindrical part

[0109] 48・・・Top wall part

[0110] 49・・・Groove

[0111] 51・・・Incision

[0112] 52・・・First cylindrical part

[0113] 53・・・Second cylindrical part

[0114] 54・・・Protrusion

[0115] 55・・・Stairs

[0116] 56・・・Mold cavity

Claims

1. An actuator, characterized in that: The actuator includes an actuator case made of resin and an actuator mechanism accommodated in the actuator case. The output member of the actuator mechanism is arranged in a manner penetrating the output hole of the actuator housing. A protective cover is mounted on the actuator housing, and the protective cover covers the outer portion of the output component protruding out of the output hole. A plurality of first protruding walls are formed on the outer end side of the output hole, the plurality of first protruding walls protrude radially inward from the inner circumference of the output hole and are arranged with first gaps therebetween in the circumferential direction of the output hole. In addition, a plurality of second protruding walls are formed on the inner end side of the output hole, the plurality of second protruding walls protrude radially inward from the inner circumferential surface of the output hole and are arranged with second gaps therebetween in the circumferential direction of the output hole. The first protruding wall and the second protruding wall are arranged so as not to overlap each other when the output hole is viewed from above. The first protruding wall and the second protruding wall define an installation groove on the inner peripheral surface of the output hole for installing the installation portion of the protection cover.

2. The actuator according to claim 1, characterized in that A width of a first gap between the first protruding walls is set to be larger than a length of the second protruding wall along a circumferential direction of the output hole.

3. The actuator according to claim 1, characterized in that The protruding height of the second protruding wall is set to be greater than the protruding height of the first protruding wall, and the second protruding wall supports the mounting portion during the mounting process of the mounting portion in the mounting groove.

4. The actuator according to claim 1, characterized in that A length of the first protruding wall along the circumferential direction of the output hole is set to be smaller than a length of the second protruding wall along the circumferential direction of the output hole.

5. The actuator according to any one of claims 1 to 4, characterized in that: A reinforcement member is embedded in the mounting portion.

6. A method for manufacturing an actuator housing, characterized in that: The actuator housing has: An output hole, which is arranged in a manner for the output component to pass through; The mounting groove is provided with a mounting portion for mounting a protective cover, wherein the protective cover covers an outer portion of the output component protruding out of the output hole, The mounting groove is divided on the inner circumferential surface of the output hole by a plurality of first protruding walls and a plurality of second protruding walls, wherein the plurality of first protruding walls are protruding inwardly in the radial direction at the outer end of the output hole and are arranged with a first gap in between along the circumferential direction of the output hole, and the plurality of second protruding walls are protruding inwardly in the radial direction at the inner end of the output hole and are arranged with a second gap in between along the circumferential direction of the output hole, The first protruding wall and the second protruding wall are arranged so as not to overlap each other when the output hole is viewed from above. In the step of molding the actuator housing with resin, A core is provided to form the inner peripheral surface of the output hole, wherein the core is configured so that a first core half located on the outer end side of the output hole and a second core half located on the inner end side of the output hole can be axially separated and fitted together. A first recess and a second recess are defined between the first core half and the second core half to form the first protruding wall and the second protruding wall, respectively. Resin is injected into a cavity that is defined by the first core half body, the second core half body, and an outer mold that forms an outer surface of the actuator housing and includes the first recessed portion and the second recessed portion.

7. A core used in the method for manufacturing an actuator housing according to claim 6, characterized in that: The first core half body is composed of a hollow cylindrical portion forming the inner peripheral surface of the mounting groove and a top wall portion connected to the outer end of the hollow cylindrical portion. The top wall portion is provided with a groove portion corresponding to the first protruding wall, The hollow cylindrical portion is provided with a cutout corresponding to the second gap between the second protruding walls. The second core half body is composed of a first cylindrical portion that can be inserted and removed into the inner circumferential surface of the hollow cylindrical portion and a second cylindrical portion that is connected to the first cylindrical portion and has a larger diameter than the first cylindrical portion. The first cylindrical portion is provided with a protrusion, and the protrusion engages with the cutout and cooperates with the groove to divide the first recessed portion. The second recessed portion is defined by the front end surface of the hollow cylindrical portion, the protrusion, and a step portion between the first cylindrical portion and the second cylindrical portion.

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