JP5297279B2 - Insert molding apparatus and insert molding method, rotor, motor, and watch - Google Patents

Description

  The present invention relates to an insert molding device and an insert molding method, a rotor manufactured by the molding method, a motor including the rotor, and a timepiece including the motor.

  Generally, a rotor of a motor mounted on a timepiece includes a disk-shaped magnet and a rotor pinion main body made of a resin material in which the magnet is embedded (see, for example, Patent Document 1). The rotor kana body includes a frame body portion formed so as to cover the periphery of the magnet, a pair of tenon portions formed on both axial end surfaces of the frame body portion and extending on the central axis of the magnet, and a tenon And a kana part (gear part) formed in the part.

The above-described rotor is manufactured by using an insert molding device (hereinafter referred to as a molding device), positioning a magnet in a mold cavity of the molding device, and insert-molding the magnet with a resin material. As a method for positioning the magnet in the cavity, first, a clearance for forming a frame body portion is set between the inner peripheral surface of the cavity and the outer peripheral surface of the magnet, and the magnet is positioned based on this clearance. There is a way.
Second, as shown in FIG. 10, a plurality of slide cores 101 that can reciprocate along the radial direction of the cavity 100 are provided along the circumferential direction of the cavity 100, and are accommodated in the cavity 100 by these slide cores 101 ( There is a method of positioning the inserted magnet 102. Specifically, after the magnet 102 is accommodated in the cavity 100, each slide core 101 is driven toward the radial center of the cavity 100 by driving means such as an air cylinder. Then, when the tip surface of each slide core 101 abuts on the outer peripheral surface of the magnet 102, the magnet 102 is held by the tip surface of each slide core 101, and the magnet 102 is positioned in the cavity 100. .

Japanese Patent Laid-Open No. 62-277057

  By the way, in manufacturing the rotor described above, further improvement in the axial center accuracy (passage accuracy) between the central axis of the magnet and the central axis of the tenon portion is required. If the accuracy of the axial center between the magnet and the tenon is poor, the central axis of the tenon is eccentric with respect to the central axis of the magnet, and the balance during rotation is lost. As a result, the performance of the motor may be reduced.

Among the insert molding methods described above, in the first method, the magnet positioning accuracy is determined by the size of the clearance between the cavity and the magnet. Therefore, if the clearance is set as small as possible, it becomes difficult to supply the magnet into the cavity when the magnet is accommodated. And when supplying a magnet in a cavity, there exists a possibility that the opening edge of a cavity and the corner | angular part of a magnet may contact, and a cavity may be worn out or the corner | angular part of a magnet may be damaged.
On the other hand, if the clearance is set so large that the magnet and the cavity do not reliably come into contact with each other when the magnet is supplied, there is a problem that the positioning accuracy is lowered and the axial center variation between the magnet and the tenon portion is increased.

Further, in the second method, as shown in FIG. 10, a large number of parts such as an air cylinder and its connecting mechanism are required to move the slide core 101, and as a result, the molding apparatus is increased in size. There's a problem. In particular, when manufacturing minute parts such as a timepiece motor, there is a problem that the structure of a molding apparatus becomes excessively complicated with respect to a molded product to be molded.
Further, it is difficult to adjust the movement amount (displacement) of the slide core 101, and accordingly, it is difficult to adjust the pressing force acting on the magnet 102 from the slide core 101. If the pressing force acting on the magnet 102 is too strong, there is a problem that the magnet 102 is damaged or the slide core 101 is heavily worn.

Accordingly, the present invention has been made in view of the above-described problems, and is intended to reduce the size and simplify the configuration and improve positioning accuracy while preventing damage to insert parts and wear of the positioning core. It is an object of the present invention to provide an insert molding apparatus and an insert molding method capable of performing the above.
Another object of the present invention is to provide a rotor manufactured by the molding method that has high axial accuracy and can exhibit stable performance over a long period of time, a motor including the rotor, and a timepiece including the motor. To do.

In order to solve the above-described problems, the present invention provides the following means.
In the insert molding device according to the present invention, a resin material is injected into the cavity in a state where the insert part is accommodated in the cavity of the mold, so that the resin molded part is placed around the insert part. In an insert molding apparatus that integrally molds, a positioning core is provided that is movable in the radial direction of the cavity and holds the insert part in the cavity, and the positioning core has a diameter when the insert part is positioned. A first core that is pressed toward the center in the direction; a second core that is disposed radially inward of the first core and that can contact an outer peripheral surface of the insert part; and the first core And a first elastic member that connects the second core and urges the first core and the second core in a direction in which the first core and the second core are separated from each other. It is characterized in that.

According to this configuration, when the insert part is positioned, the first core is pressed toward the radial center, so that the second core also moves toward the radial center via the first elastic member. . And when the front end surface of the second core is in contact with the outer peripheral surface of the insert part, the insert part is pressed toward the center in the radial direction, and the center axis of the insert part is aligned with the center axis of the cavity. The positioning of the insert part can be performed.
In particular, when the first core is pressed after the tip surface of the second core contacts the outer peripheral surface of the insert part, the first elastic member contracts, so that the displacement of the second core is the first. Smaller than the displacement of the core. Therefore, the displacement of the second core can be finely adjusted compared to the displacement of the first core. Further, even if the first core is pressed while the insert part is held by the second core, the first elastic member contracts, so that an excessive pressing force acts from the second core toward the insert part. The insert part can be pressed without any trouble. As a result, the insert component is positioned in the cavity so that the center axis of the insert component and the center axis of the cavity coincide with each other, and the insert component is held with a desired pressing force in a state where the insert component is positioned. can do. As a result, it is possible to provide a molded product with high axial accuracy between the insert part and the resin molded part.
In addition, the clearance between the cavity and the insert part can be easily managed as compared with the conventional first method described above, and the displacement of the positioning core, that is, the second core is changed to the insert part as compared with the second method. Adjustment of the acting pressing force is facilitated. As a result, damage to the insert parts and wear of the positioning core can be suppressed, so that manufacturing costs can be reduced and manufacturing efficiency can be improved.

The molding die is divided into a first die and a second die that is movable relative to the first die in the axial direction. The first die includes: The positioning core is provided, and the second die includes a protruding portion that protrudes in the axial direction toward the first die, and the second die and the first die are arranged along the axial direction. When the relative movement is performed, the projecting portion comes into contact with the first core, and the first core is moved inward in the radial direction.
According to this configuration, at the time of clamping the first mold and the second mold, the positioning core moves toward the radial center in synchronization with the relative movement between the first mold and the second mold. Therefore, as compared with the configuration in which the positioning core is driven by a separate air cylinder or the like as in the conventional second method, the apparatus can be downsized and the configuration can be simplified.

In addition, a plurality of the positioning cores are arranged along the circumferential direction of the cavity.
According to this configuration, since the outer peripheral surface of the insert part is pressed from a plurality of directions by the tip surface of the second core in each positioning core, the magnet can be stably held in the cavity. .
In particular, as described above, when these positioning cores move in synchronization with the relative movement between the first mold and the second mold, the movement timing and movement amount of each positioning core are evenly distributed among the positioning cores. Become. That is, each positioning core presses the insert part toward the center in the radial direction, so that the center axis of the insert part is arranged at the intersection (center axis of the cavity) of the action line (movement direction) of the positioning core. Insert parts move smoothly. As a result, the insert part is positioned in the cavity in a state where the center axis of the insert part and the center axis of the cavity coincide with each other. Thereby, the axial center precision of the center axis | shaft of insert components and the center axis | shaft of a resin molding part can be improved.

The positioning core includes a second elastic member that urges the second core toward the radially outer side.
According to this configuration, since the second core is biased radially outward by the second elastic member, the second elastic member contracts as the second core starts to move. Due to this, an elastic force is generated from the second elastic member toward the second core. That is, before the second core comes into contact with the insert component, an elastic force is generated in the second core in a direction against the moving direction of the positioning core. Thereby, compared with the case where a 2nd elastic member is not employ | adopted, the impact at the time of a 2nd core contact | abutting to insert components can be relieve | moderated. As a result, it is possible to hold the insert part with a desired pressing force and further suppress damage to the insert part and wear of the positioning core.
Further, since the second elastic member is biased radially outward, the second core moves radially outward by releasing the pressing force acting on the first core, and the insert part It will be away from. Therefore, the positioning core releasing operation as a separate process is not necessary, and the molded product can be easily taken out. Further, thereafter, the insert part can be easily supplied into the cavity at the time of the molding process of the next insert part. Thereby, the improvement of manufacturing efficiency can be aimed at.

The positioning core includes a third elastic member that urges the first core toward the radially outer side.
According to this configuration, since the pressing force acting on the first core toward the center in the radial direction is distributed to the first elastic member and the third elastic member, compared to the case where the third elastic member is not employed, The elastic force generated in one elastic member can be reduced. Therefore, the impact when the second core comes into contact with the insert part can be mitigated, and an excessive pressing force does not act on the outer peripheral surface of the insert part.
Further, since the third elastic member is biased radially outward, the first core moves radially outward by releasing the pressing force acting on the first core. Thus, it is separated from the insert part. Therefore, the positioning core releasing operation as a separate process is not necessary, and the molded product can be easily taken out. Further, thereafter, the insert part can be easily supplied into the cavity at the time of the molding process of the next insert part. Thereby, the improvement of manufacturing efficiency can be aimed at.

The insert molding method according to the present invention includes a positioning core that is movable in a radial direction of a cavity in a mold and holds an insert part in the cavity, and the positioning core is used for positioning the insert part. A first core that is pressed toward the center in the radial direction; a second core that is disposed radially inward of the first core and that can contact the outer peripheral surface of the insert part; and the first core An insert molding apparatus comprising: a first elastic member that connects a core and the second core and urges the first core and the second core in a direction to separate the first core and the second core; By injecting a resin material into the cavity in a state in which the insert part is accommodated therein, a resin molded portion is integrated with the insert part around the insert part. An insert molding method for molding, comprising: a housing step of housing the insert component in the cavity; and a positioning step of positioning the insert component in the cavity by the positioning core. By pressing the first core toward the radial center, the second core is moved inward in the radial direction via the first elastic member, and the tip surface of the second core is moved to the insert part. The insert part is held in the cavity in contact with an outer peripheral surface.
According to this configuration, when the first core is pressed toward the radial center in the positioning step, the second core also moves toward the radial center via the first elastic member. And when the front end surface of the second core is in contact with the outer peripheral surface of the insert part, the insert part is pressed toward the center in the radial direction, and the center axis of the insert part is aligned with the center axis of the cavity. The positioning of the insert part can be performed.
In particular, when the first core is pressed after the tip surface of the second core contacts the outer peripheral surface of the insert part, the first elastic member contracts, so that the displacement of the second core is the first. Smaller than the displacement of the core. Therefore, the displacement of the second core can be finely adjusted compared to the displacement of the first core. Further, even if the first core is pressed while the insert part is held by the second core, the first elastic member contracts, so that an excessive pressing force acts from the second core toward the insert part. The insert part can be pressed without any trouble. As a result, the insert component is positioned in the cavity so that the center axis of the insert component and the center axis of the cavity coincide with each other, and the insert component is held with a desired pressing force in a state where the insert component is positioned. can do. As a result, it is possible to provide a molded product with high axial accuracy between the insert part and the resin molded part.
In addition, the clearance between the cavity and the insert part can be easily managed as compared with the conventional first method described above, and the displacement of the positioning core, that is, the second core is changed to the insert part as compared with the second method. Adjustment of the acting pressing force is facilitated. As a result, damage to the insert parts and wear of the positioning core can be suppressed, so that manufacturing costs can be reduced and manufacturing efficiency can be improved.

The rotor according to the present invention is a rotor manufactured using the insert molding method according to the present invention, wherein the insert part is a magnet, and the resin molded portion is formed so as to surround the magnet. And a pair of shaft portions formed on both end surfaces in the axial direction of the frame portion and extending on the central axis of the magnet, and a gear portion formed on the shaft portion. It is characterized by being.
According to this structure, since it is manufactured by the insert molding method of the present invention, it is possible to manufacture a rotor having excellent axial center accuracy between the magnet and the shaft portion.

A motor according to the present invention includes the rotor according to the present invention.
According to this configuration, since the rotor according to the present invention is provided, the balance during rotation of the rotor is stabilized, and the load acting on the shaft portion can be reduced. Thereby, abrasion and damage of the shaft portion can be suppressed. Therefore, it is possible to provide a high-performance motor that can exhibit stable motor performance over a long period of time.

A timepiece according to the present invention includes the motor according to the present invention.
According to this configuration, since the motor of the present invention is provided, a high-performance timepiece that can be stably operated with low power for a long period of time while suppressing energy loss and mechanical damage is provided. be able to.

According to the insert molding device and the molding method according to the present invention, when the insert part is positioned, the first core is pressed toward the center in the radial direction, whereby the second core is interposed via the first elastic member. Also moves towards the radial center. And when the front end surface of the second core is in contact with the outer peripheral surface of the insert part, the insert part is pressed toward the center in the radial direction, and the center axis of the insert part is aligned with the center axis of the cavity. The positioning of the insert part can be performed.
In particular, when the first core is pressed after the tip surface of the second core contacts the outer peripheral surface of the insert part, the first elastic member contracts, so that the displacement of the second core is the first. Smaller than the displacement of the core. Therefore, the displacement of the second core can be finely adjusted compared to the displacement of the first core. Further, even if the first core is pressed while the insert part is held by the second core, the first elastic member contracts, so that an excessive pressing force acts from the second core toward the insert part. The insert part can be pressed without any trouble. As a result, the insert component is positioned in the cavity so that the center axis of the insert component and the center axis of the cavity coincide with each other, and the insert component is held with a desired pressing force in a state where the insert component is positioned. can do. As a result, it is possible to provide a molded product with high axial accuracy between the insert part and the resin molded part.
In addition, the clearance between the cavity and the insert part can be easily managed as compared with the conventional first method described above, and the displacement of the positioning core, that is, the second core is changed to the insert part as compared with the second method. Adjustment of the acting pressing force is facilitated. As a result, damage to the insert parts and wear of the positioning core can be suppressed, so that manufacturing costs can be reduced and manufacturing efficiency can be improved.
Since the rotor according to the present invention is manufactured by the above-described insert molding method of the present invention, it is possible to provide a rotor having excellent axial center accuracy between the magnet and the shaft portion.
The motor according to the present invention can provide a high-performance motor capable of exhibiting stable motor performance over a long period of time.
According to the timepiece of the present invention, it is possible to provide a high-performance timepiece that can be stably operated with low power for a long period of time while suppressing energy loss and mechanical damage.

It is a schematic block diagram (plan view) of a timepiece. It is a perspective view of a rotor. It is a perspective view of the shaping | molding apparatus which shows the state before the mold clamping of an upper mold | type and a lower mold | type. It is a perspective view of the shaping | molding apparatus which shows the state after mold clamping with an upper mold | type and a lower mold | type. It is sectional drawing which follows the AA line of FIG. It is a top view of a lower mold. It is sectional drawing of the shaping | molding apparatus corresponded in FIG. 5, and has shown the time of mold clamping with an upper mold | type and a lower mold | type. FIG. 6 is a cross-sectional view of the molding apparatus corresponding to FIG. 5, showing a state where clamping of the upper mold and the lower mold is completed. It is a top view of the lower mold | type at the time of completion | finish of mold clamping. It is a top view of the conventional shaping | molding apparatus.

Next, embodiments of the present invention will be described with reference to the drawings.
(clock)
FIG. 1 is a schematic configuration diagram (plan view) of a timepiece.
As shown in FIG. 1, the timepiece 1 includes a base plate 10 that is a circular support in a plan view, a motor 11, a train wheel 12, an external operation member 13, a quartz vibrator (not shown), a circuit block, and the like. The component parts are assembled and configured.

(Rotor)
FIG. 2 is a perspective view of the rotor.
As shown in FIGS. 1 and 2, the motor 11 includes a cylindrical stator (not shown) provided on the main plate body 10 and a rotor 21 that is disposed inside the stator and is rotatably supported by the stator. Yes. As shown in FIG. 2, the rotor 21 includes a magnet 22 and a rotor pinion main body (resin molding portion) 23 as a rotor main body. The magnet 22 has a disk shape and is magnetized along its radial direction.

The rotor kana main body 23 is integrally formed by insert-molding the magnet 22 with a resin material, and includes a frame body portion 31, a pair of tenon portions (shaft portions) 33 and 34, and a kana portion (gear portion). 32.
The frame body portion 31 is a columnar member formed so as to surround the magnet 22, and a plurality of cutout portions 35 are formed at equal intervals along the circumferential direction. These cutout portions 35 are formed in an arc shape from the outer peripheral edge of the frame body portion 31 toward the central portion in the radial direction, and the outer peripheral edge of the magnet 22 is exposed from the cutout portion 35.

The tenon portions 33 and 34 extend from the front and back surfaces of the frame portion 31 onto the central axis C <b> 1 of the magnet 22. Of the tenon portions 33, 34, one end portion of the tenon portion 33 is rotatably supported by the main plate body 10, and the other end portion of the tenon portion 34 is rotatably supported by the train wheel bridge. The rotor 21 is rotatably supported.
The pinion portion 32 is integrally formed on the base end side of the other tenon portion 34, and is formed so as to protrude radially outward over the entire circumference of the tenon portion 34. Note that gear teeth are formed on the outer peripheral surface of the kana portion 32.

  The kana portion 32 is engaged with the wheel train 12 (see FIG. 1) rotatably supported by the train wheel bridge so that the rotational force of the rotor 21 can be transmitted to the wheel train 12. Then, the train wheel 12 is rotated by the rotational force of the rotor 21 so that the time display hand (not shown) of the timepiece 1 is moved.

(Insert molding equipment)
Here, an insert molding apparatus (hereinafter referred to as a molding apparatus) for manufacturing the rotor 21 described above will be described. FIG. 3 is a perspective view of the molding apparatus showing a state before clamping the upper mold and the lower mold, and FIG. 4 is a perspective view of the molding apparatus showing a state after clamping. FIG. 5 is a sectional view taken along the line AA in FIG.
3-5, the shaping | molding apparatus 41 is arrange | positioned coaxially with the central axis C2 of the disk-shaped lower mold | type (1st type | mold) 42 and the lower mold | type 42, and reciprocates along an axial direction. An upper die (second die) 43 that is made possible and a positioning mechanism (positioning core) 44 that is provided on the lower die 42 and holds the magnet 22 that is an insert member.

The lower mold 42 has a disk shape, and has a base 45 formed in the lower part and a reduced diameter part 46 (formed in the upper part and having an outer diameter reduced compared to the base 45 by cutting out the outer peripheral edge. 3). That is, a stepped portion 47 (see FIG. 3) is formed on the radially outer side of the reduced diameter portion 46.
The lower mold 42 includes a lower mold cavity 48 in which the magnet 22 is accommodated in the central portion in the radial direction. The lower die cavity 48 has a circular shape in a plan view formed by the lower die 42 being pierced downward in the axial direction. The lower mold cavity 48 can mold the lower half portion of the rotor pinion main body 23 in the axial direction (for example, the tenon portion 34 side) around the magnet 22 by injecting a resin material around the magnet 22 at the time of molding. It is like that. 3 to 5, the shape of the lower mold cavity 48 and an upper mold cavity 84 to be described later are simplified for easy understanding.

  The positioning mechanism 44 is accommodated in a plurality of (for example, three) guide grooves 49 formed at equal intervals along the circumferential direction of the lower mold cavity 48, and is respectively accommodated in the guide grooves 49. It has a plurality of slide cores 50 (see FIG. 3) configured to be slidable in the direction, and elastic members 62, 66, and 74 described later. That is, the intersection of the action lines (slide direction) of each slide core 50 is arranged on the central axis C <b> 2 of the lower mold 42. Then, the slide core 50 is configured to hold the magnet 22 between the slide cores 50 by pressing the outer peripheral surface of the magnet 22 accommodated in the lower mold cavity 48 from three places in the circumferential direction. Since each guide groove 49 and slide core 50 have the same configuration, only one guide groove 49 and slide core 50 will be described in the following description.

FIG. 6 is a plan view of the lower mold.
As shown in FIGS. 3 to 6, the guide groove 49 is formed so as to communicate with the lower mold cavity 48 from the outer peripheral edge of the lower mold 42, and is gradually formed in the lower mold 42 from the outer peripheral side toward the inner peripheral side. The length (height) in the axial direction is increased. That is, a lower step portion 52, a middle step portion 53, and an upper step portion 54 are sequentially formed on the lower surface of the guide groove 49 from the outer peripheral side toward the inner peripheral side.
Further, the inner peripheral side, the middle step portion 53 and the upper step portion 54 of the lower step portion 52 are formed by cutting along the axial direction from the upper surface of the reduced diameter portion 46, and the outer periphery side of the lower step portion 52 is It is cut in the axial direction from the upper surface of the base 45. That is, on the outer peripheral side of the lower step portion 52, the axial length of the side wall that surrounds the lower step portion 52 is larger than the axial length of the inner peripheral side of the lower step portion 52, the middle step portion 53, and the upper step portion 54. It is formed low. Further, the end portion on the outer peripheral side of the lower step portion 52 is not open to the outer peripheral surface of the base portion 45 and remains at the same height as the base portion 45. This remaining portion is configured as a stopper 60 that restricts the movement of the slide core 50 outward in the radial direction.

As shown in FIGS. 3 and 4, the slide core 50 is divided along the radial direction, and includes a base core (first core) 61 disposed on the outer peripheral side of the lower mold 42, and the lower mold 42. The holding core (second core) 63 is arranged on the inner peripheral side and connected to the tip of the base core 61 via a first elastic member 62.
The base core 61 is bent in an L shape, and includes a foot portion 64 extending along the axial direction and an arm portion 65 extending radially inward from the tip of the foot portion 64. It is integrally formed. The foot portion 64 is formed in a prismatic shape, and its proximal end is accommodated in a guide groove 49 on the outer peripheral side of the lower step portion 52, and is held in the guide groove 49 so as to be slidable on the lower step portion 52 in the radial direction. . Further, a third elastic member 66 is connected between the end surface on the radially inner side of the foot portion 64 and the end surface on the radially outer side of the middle step portion 53, and the base core 61 is attached facing the radially outer side. It is fast. The second elastic member 74 will be described later.

  The arm portion 65 has a prismatic shape that is bent at approximately 90 degrees from the tip of the foot portion 64 with respect to the foot portion 64, and is accommodated in the guide groove 49 on the inner peripheral side of the lower step portion 52. In addition, on the radially outer end face of the base core 61, the corner portion formed between the foot portion 64 and the arm portion 65 is formed with an inclined surface 67 that is cut along the direction intersecting the axial direction. ing.

  The holding core 63 is an L-shaped member similar to the base core 61, and includes a foot portion 72 extending along the axial direction and an arm portion 73 extending radially inward from the tip of the foot portion 72. And are integrally formed. The foot portion 72 is formed in a prismatic shape, and its proximal end side is accommodated in the guide groove 49 of the middle step portion 53 and is held in the guide groove 49 so as to be slidable on the middle step portion 53 in the radial direction. Further, a second elastic member 74 is connected between the end surface on the radially inner side of the foot portion 72 and the end surface on the radially outer side of the lower step portion 52, and the pressing core 63 is attached facing the radially outer side. It is fast.

  The arm portion 73 has a prismatic shape that is bent from the tip of the foot portion 72 to the foot portion 72 at approximately 90 degrees, and is accommodated in the guide groove 49 of the middle step portion 53 and the upper step portion 54. Further, the arm portion 73 extends to a position where the distal end side thereof is desired in the lower mold cavity 48, and a concave portion 75 cut out in an arc shape in a plan view is formed on the distal end surface. The recess 75 is configured to be able to come into contact with the outer peripheral surface of the magnet 22 accommodated in the lower mold cavity 48, and has a radius of curvature equal to or larger than that of the outer peripheral surface of the magnet 22. In the initial position of the slide core 50 (before the upper mold 43 and the lower mold 42 are clamped), the slide core 50 is urged radially outward by the elastic members 62, 66 and 74. In this case, when the foot 64 of the base core 61 abuts against the stopper 60, the movement of the slide core 50 outward in the radial direction is restricted, while being accommodated in the recess 75 and the lower mold cavity 48 of the pressing core 63. A predetermined clearance is set between the outer peripheral surface of the magnet 22.

  Here, the base core 61 and the pressing core 63 are connected by the first elastic member 62 described above. The first elastic member 62 is interposed between the distal end surface of the arm portion 65 of the base core 61 and the radially outer end surface of the foot portion 72 of the pressing core 63, and the base core 61 and the pressing core 63 are connected to each other. It is energizing toward the direction which mutually separates. If the spring constants of the first elastic member 62, the second elastic member 74, and the third elastic member 66 are k1, k2, and k3, respectively, these spring constants k1 to k3 can be set arbitrarily. However, it is preferable to set the spring constant of the second elastic member 74 to be larger than the spring constant of the first elastic member 62 (k2> k1).

The upper die 43 is a disk-like member having an outer diameter that is the same as that of the lower die 42, and is configured to be reciprocally movable along the axial direction by a driving means (not shown) such as an air cylinder. The upper die 43 has a central axis C2 arranged coaxially with the central axis C2 of the lower die 42, and a recess 83 surrounded by a peripheral wall (projecting portion) 82 is formed on the lower surface side. The recess 83 is formed so that the axial length (depth) is equal to the axial length of the reduced diameter portion 46 of the lower mold 42 described above, and the inner diameter is slightly larger than the reduced diameter portion 46. ing. In other words, when the lower mold 42 and the upper mold 43 are clamped, the concave portion 83 of the upper mold 43 and the reduced diameter portion 46 of the lower mold 42 are configured to fit together.
In addition, an upper mold cavity 84 is formed in the central portion of the concave portion 83 in the radial direction. The bottom portion of the concave portion 83 is pierced upward in the axial direction. The upper mold cavity 84 has the same shape as the upper half portion in the axial direction of the rotor pinion main body 23 described above, and a resin material is injected around the magnet 22 at the time of molding. The upper half of the kana body 23 in the axial direction can be molded. That is, when the upper mold 43 and the lower mold 42 are clamped, the magnet 22 is inserted into the space formed by the upper mold cavity 84 and the lower mold cavity 48, and the rotor is formed around the magnet 22. The main body 23 is formed.

  The peripheral wall 82 protrudes downward in the axial direction, and an inclined surface 85 formed by cutting the peripheral wall 82 in a direction intersecting the axial direction is formed on the inner peripheral edge thereof. The inclined surface 85 is formed over the entire circumference of the inner peripheral edge of the peripheral wall 82, and is formed so that the thickness of the peripheral wall 82 gradually increases toward the upper side in the axial direction. That is, the inner diameter of the recess 83 surrounded by the peripheral wall 82 is formed so as to gradually decrease from the opening side toward the bottom. The inclined surface 85 is formed so that the angle with respect to the axial direction is equal to the angle with respect to the axial direction of the inclined surface 67 formed on the base core 61, and when the upper mold 43 and the lower mold 42 are clamped. These inclined surfaces 67 and 85 are configured to slide with each other.

(Insert molding method)
Next, an insert molding method for manufacturing a rotor using the above-described molding apparatus will be described.
As shown in FIGS. 3, 5, and 6, first, the magnet 22 is accommodated in the lower mold cavity 48 so that the central axis C <b> 2 of the lower mold 42 and the central axis C <b> 1 of the magnet 22 are at least parallel. Process). In this state, the slide core 50 is urged radially outward by the elastic members 62, 66, and 74, and is held in the initial position.

FIG. 7 is a cross-sectional view of the molding apparatus corresponding to FIG. 5 and shows a state in which the upper mold and the lower mold are clamped.
Next, the lower mold 42 and the upper mold 43 are clamped by a predetermined clamping force, and the magnet 22 is positioned in the lower mold cavity 48 (positioning step). Specifically, as shown in FIG. 7, when the driving means is operated to lower the upper mold 43 along the axial direction of the lower mold 42, first, an inclined surface 85 formed on the peripheral wall 82 of the upper mold 43 and The inclined surface 67 formed on each base core 61 comes into contact. When the inclined surfaces 67 and 85 come into contact with each other, the upper die 43 is lowered while the inclined surface 85 of the upper die 43 is in sliding contact with the inclined surface 67 of each base core 61.

At this time, a clamping force acts on the base core 61 from the upper mold 43 along the axial direction. Then, the component force of this clamping force is transmitted to each slide core 50 as a pressing force F acting toward the center in the radial direction via the inclined surface 67 of each base core 61. With this pressing force F, each base core 61 is pressed toward the center in the radial direction, and each base core 61 begins to slide in the guide groove 49 toward the center in the radial direction all at once. Thereby, the clearance between the concave portion 75 of the pressing core 63 and the outer peripheral surface of the magnet 22 is gradually reduced.
When the base core 61 slides toward the center in the radial direction, the second and third elastic members 66 and 74 are contracted following this, and elastic forces F2 and F3 are generated in the second and third elastic members 66 and 74, respectively. . Further, the elastic force F <b> 2 acts from the second elastic member 74 toward the pressing core 63, whereby the first elastic member 62 contracts. Thereby, the elastic force F <b> 1 is also generated in the first elastic member 62.

  Then, as the upper mold 43 is further lowered, the inclined surface 85 of the upper mold 43 slides on the inclined surface 67 of the base core 61, and the slide cores 50 are further centered in the radial direction following this. Slide towards you. As a result, the recess 75 of each pressing core 63 simultaneously contacts the outer peripheral surface of the magnet 22 and presses the magnet 22 toward the radial center.

FIG. 8 is a cross-sectional view of the molding apparatus corresponding to FIG. 5 and shows the time when the upper mold and the lower mold are clamped. FIG. 9 is a plan view of the lower mold when the mold clamping is completed.
Here, as shown in FIGS. 7 to 9, when the base core 61 is pressed against the upper mold 43 after the recess 75 of the base core 61 contacts the outer peripheral surface of the magnet 22, the first and third elastic members 62, 66 further contracts. At this time, the displacement L2 of the pressing core 63 is smaller than the displacement L1 of the base core 61. Specifically, if the displacement of the base core 61 is L1 and the displacement of the holding core 63 is L2, the elastic force F1 generated in the first elastic member 62 is F1 = k1 (L1-L2) (Equation 1) Become. Further, the elastic force F2 generated in the second elastic member 74 is F2 = k2L2 (Expression 2). Since F1 = F2 when the concave portion 75 of the base core 61 is in contact with the outer peripheral surface of the magnet 22, k2L2 = k1 (L1-L2) (Equation 3), and the second elastic member from (Equation 3). The displacement L2 of 74 is L2 = (k1L1) / (k1 + k2) (Expression 4).
In this case, since k1> 0 and k2> 0, the displacement L2 of the second elastic member 74 is necessarily smaller than the displacement L1 of the first elastic member 62 (L1> L2).

  Thereby, the magnet 22 gradually moves in the lower mold cavity 48 to a position where the central axis C1 coincides with the central axis C2 of the lower mold 42 while being pressed by the pressing core 63. As a result, the magnet 22 is positioned at the center in the lower mold cavity 48. When the upper die 43 is further lowered after the magnet 22 is positioned, the base core 61 moves toward the center in the radial direction, but the first and third elastic members 62 and 66 are contracted. Excessive pressure does not work.

After that, as shown in FIGS. 8 and 9, the boundary portion 90 on the upper side in the axial direction of the inclined surface 85 of the upper mold 43 gets over the boundary portion 91 on the lower side of the inclined surface 67 of the base core 61. The reduced diameter portion 46 of the lower mold 42 is accommodated in the concave portion 83 of the lower mold 42, and the pressing force F directed from the upper mold 43 toward the center in the radial direction is constant. At this time, since the reduced diameter portion 46 of the lower die 42 and the recess 83 of the upper die 43 are inlay-fitted, the radially outer end surface of the base core 61 contacts the inner peripheral surface of the peripheral wall 82 of the upper die 43. Will do. Therefore, the movement of the base core 61 outward in the radial direction is restricted. And the movement of the upper mold | type 43 stops because the end surface of the surrounding wall 82 of the upper mold | type 43 abuts on the level | step-difference part 47 of the lower mold | type 42. FIG. Thus, in this embodiment, when the lower mold | type 42 and the upper mold | type 43 collide, desired pressing force is provided to the magnet 22 from the pressing core 63, and it sets so that positioning may be completed. Therefore, each magnet 22 can be positioned at the same position and with the same pressing force at the time of positioning each time.
Thus, the clamping of the upper mold 43 and the lower mold 42 is completed.

  After mold clamping, the resin material is injection-molded by filling the melted resin material into the cavities 48 and 84 and cooling the molding device 41. This injection molding can be performed by a known method.

Subsequently, after the resin material is cured, the upper mold 43 and the lower mold 42 are opened. Specifically, the driving means is driven to raise the upper mold 43 along the axial direction. When the boundary portion 90 of the inclined surface 85 in the upper mold 43 gets over the boundary portion 91 of the inclined surface 67 of the base core 61, the slide core 50 moves inside the guide groove 49 by the restoring force of each elastic member 62, 66, 74. Slide gradually toward the outside in the radial direction. In this case, the inclined surfaces 67 and 85 slide at a constant speed by raising the upper mold 43 at a constant speed. Therefore, each slide core 50 is separated from the molded product (rotor 21) at an equal speed. Thereby, when the mold is opened, contact between the slide core 50 and the molded product can prevent wear of the slide core 50 or damage to the molded product.
As described above, the rotor 21 is completed by the molding apparatus 40.

Thus, in the present embodiment, the base core 61 and the pressing core 63 are connected via the first elastic member 62.
According to this configuration, when the magnet 22 is positioned, the slide core 50 moves toward the radial center by pressing the base core 61 toward the radial center. The concave portion 75 of the pressing core 63 comes into contact with the outer peripheral surface of the magnet 22 so that the magnet 22 is pressed toward the center in the radial direction so that the central axis C1 of the magnet 22 and the central axis C2 of the lower mold cavity 48 coincide with each other. In this state, the magnet 22 can be positioned.
In particular, since the base core 61 and the pressing core 63 are coupled via the first elastic member 62 as described above, the displacement L2 of the pressing core 63 is smaller than the displacement L1 of the base core 61. Therefore, the displacement L2 of the pressing core 63 can be finely adjusted compared to the displacement L1 of the base core 61. Even if the base core 61 is pressed while the magnet 22 is held by the pressing core 63, the first elastic member 62 contracts, so that excessive pressing force does not act from the pressing core 63 toward the magnet 22. The magnet 22 can be pressed. As a result, the magnet 22 is positioned in the cavities 48 and 84 in a state where the magnet 22 is positioned in the lower mold cavity 48 so that the center axis C1 of the magnet 22 and the center axis C2 of the lower mold cavity 48 coincide. Can be held with a desired pressing force. As a result, in the rotor 21 which is a molded product, the axial center accuracy between the central axis C1 of the magnet 22 and the tenon portions 33 and 34 of the rotor pinion main body 23 can be improved.
Further, the clearance between the lower mold cavity 48 and the magnet 22 can be easily managed as compared with the above-described conventional first method, and the displacement of the slide core 50, that is, the pressing core 63 is compared with the second method. It is easy to adjust the pressing force. Therefore, since damage to the magnet 22 and wear of the slide core 50 can be suppressed, manufacturing cost can be reduced and manufacturing efficiency can be improved.

In addition, since the second elastic member 74 is interposed between the pressing core 63 and the upper step portion 54, the second elastic member 74 contracts as the pressing core 63 starts to move. The elastic force F <b> 2 can be applied to the pressing core 63 in a direction against the pressing force F applied from the base core 61. That is, the elastic force F <b> 2 acts on the pressing core 63 in a direction against the pressing force F before the pressing core 63 contacts the magnet 22.
In addition, since the third elastic member 66 is interposed between the base core 61 and the middle step portion 53, the pressing force F acting on the base core 61 is applied to the first elastic member 62 and the third elastic member 66. The first elastic force F <b> 1 that is dispersed and generated in the first elastic member 62 can be reduced.
Therefore, compared with the case where the second and third elastic members 74 and 66 are not employed, the pressing force of the magnet 22 by the slide core 50 can be reduced, and the impact when the pressing core 63 contacts the magnet 22 is reduced. be able to. As a result, it is possible to hold the magnet 22 with a desired pressing force while further suppressing breakage of the magnet 22 and wear of the slide core 50.

  Further, in this embodiment, when clamping the upper mold 43 and the lower mold 42, the clamping force acting along the axial direction from the upper mold 43 is applied to the center in the radial direction via the inclined surface 67 of the base core 61. Can be made to act toward. That is, since the slide core 50 slides in the guide groove 49 in synchronization with the movement of the upper die 43, the slide core 101 is driven by a separate air cylinder or the like provided in the radial direction of the lower die 42 as in the prior art. Compared to the configuration, the apparatus can be downsized and the configuration can be simplified.

  In addition, since the positioning mechanism 44 of the present embodiment is provided with a plurality of slide cores 50 at equal intervals along the circumferential direction of the lower mold cavity 48, the outer periphery of the magnet 22 is formed by the recesses 75 of these pressing cores 63. The surface is pressed from a plurality of directions. Thereby, the magnet 22 can be stably held in the lower mold cavity 48. Particularly, since these slide cores 50 slide in the guide grooves 49 in synchronization with the movement of the upper mold 43, the movement timing and movement amount of each slide core 50 are equalized among the slide cores 50. That is, after each slide core 50 simultaneously contacts the outer peripheral surface of the magnet 22, the magnet 22 smoothly moves so that the center axis C 1 of the magnet 22 coincides with the center axis C 2 of the lower mold 42 by the movement of each slide core 50. Moving. As a result, it is possible to position the magnet 22 at a desired position in the lower mold cavity 48 while further improving the axial accuracy of the center axis C1 of the magnet 22 and the center axis C2 of the lower mold 42.

Further, since the second and third elastic members 66 and 74 are urged outward in the radial direction, the slide cores 50 are simultaneously slid outward in the radial direction and separated from the magnet 22 as the mold is opened. become. Therefore, the release operation of the slide core 50 as a separate process becomes unnecessary, and the molded product can be easily taken out. Further, thereafter, the magnet 22 can be easily supplied into the lower mold cavity 48 during the next molding step.
As a result, the manufacturing efficiency can be improved.

Thus, in this embodiment, since the positioning accuracy of the magnet 22 with respect to the molding apparatus 41 (respective cavities 48 and 84) can be improved as described above, the axial center accuracy between the magnet 22 and the tenon portions 33 and 34 is improved. The rotor 21 having a high height can be manufactured.
And since the motor 11 of this embodiment is provided with the rotor 21 with high axial center precision, the balance at the time of rotation of the rotor 21 is stabilized, and the load which acts on the tenon parts 33 and 34 can be reduced. Thereby, abrasion and damage of the tenon portions 33 and 34 can be suppressed. Therefore, it is possible to provide a high-performance motor 11 capable of exhibiting stable motor performance over a long period of time.
Further, even in the timepiece 1 equipped with the motor 11, the high-performance timepiece 1 in which the timepiece 1 is stably operated at low power for a long period of time while suppressing energy loss and mechanical damage. Can be provided.

The technical scope of the present invention is not limited to the above-described embodiment, and includes various modifications made to the above-described embodiment without departing from the spirit of the present invention. That is, the specific structure and shape described in the embodiment are merely examples, and can be changed as appropriate.
In the above-described embodiment, the case where all the slide cores 50 are configured to be slidable in the guide groove 49 has been described. However, the present invention is not limited to this, and at least one of the slide cores 50 is a movable positioning core as in this embodiment. The other positioning cores may be fixed.
The number and layout of the slide cores 50 can be appropriately changed in design.
Further, in the above-described embodiment, the configuration in which the inclined surfaces 67 and 85 are formed on both the base core 61 and the peripheral wall 82 has been described. However, the inclined surface is formed on only one of them, and the other is formed on the corner. It doesn't matter. That is, the design can be changed as appropriate as long as the base core 61 is pressed toward the radial center in synchronization with the movement of the upper mold 43.
Further, at the time of mold clamping, the upper mold 43 may be fixed and the lower mold 42 may be moved relative to the upper mold 43, or the lower mold 42 and the upper mold 43 may be moved together.

Further, the elastic members 62, 66, 74 are not limited to coil springs, and leaf springs, rubbers, or the like may be used.
Further, the elastic members 62, 66, 74 may be integrated with the slide core 50.
The inclined surface 85 of the upper mold 43 and the inclined surface 67 of the base core 61 may each be configured in a tapered shape. That is, the inclined surface 85 of the upper mold 43 is linearly inclined from the inner peripheral edge of the peripheral wall 82 to the bottom, and the inclined surface 67 of the base core 61 is linearly inclined from the upper surface to the lower surface of the foot 64. It doesn't matter.

  In the above-described embodiment, the case where the present invention is applied to the manufacture of the rotor 21 has been described. That is, the present invention can be applied not only to the production of minute parts such as the watch rotor 21 but also to the production of relatively large parts.

DESCRIPTION OF SYMBOLS 1 ... Clock 21 ... Rotor 22 ... Magnet (insert part) 23 ... Rotor kana main body (resin molding part) 41 ... Molding apparatus (insert molding apparatus) 42 ... Lower mold (1st mold) 43 ... Upper mold (1st Mold) 44 ... Positioning mechanism 50 ... Slide core (positioning core) 48 ... Lower mold cavity 61 ... Base core (first core) 62 ... First elastic member 63 ... Holding core (first core) 66 ... Third elasticity Member 67, 85 ... Inclined surface 74 ... Second elastic member 82 ... Peripheral wall (projection) 84 ... Upper mold cavity

Claims (9)

An insert molding device that integrally molds a resin molding portion around the insert part with the insert part by injecting a resin material into the cavity while the insert part is accommodated in the cavity of the molding die In
A positioning core that is movable in a radial direction of the cavity and holds the insert part in the cavity;
The positioning core is a first core that is pressed toward the radial center during positioning of the insert component;
A second core disposed radially inward of the first core and capable of contacting the outer peripheral surface of the insert component;
A first elastic member that connects the first core and the second core and biases the first core and the second core in a direction in which the first core and the second core are separated from each other is provided. Insert molding equipment. The mold is divided into a first mold and a second mold that is movable relative to the first mold in the axial direction.
The first mold is provided with the positioning core;
The second mold includes a protruding portion that protrudes in the axial direction toward the first mold,
When the second mold and the first mold are relatively moved along the axial direction, the protrusion comes into contact with the first core and moves the first core inward in the radial direction. The insert molding apparatus according to claim 1, wherein the apparatus is configured as described above.   The insert molding apparatus according to claim 1, wherein a plurality of the positioning cores are arranged along a circumferential direction of the cavity.   The insert molding according to any one of claims 1 to 3, wherein the positioning core includes a second elastic member that urges the second core toward a radially outer side. apparatus.   The insert molding according to any one of claims 1 to 4, wherein the positioning core includes a third elastic member that urges the first core toward a radially outer side. apparatus. It is movable in the radial direction of the cavity in the mold, and includes a positioning core that holds the insert part in the cavity.
The positioning core is a first core that is pressed toward the radial center during positioning of the insert component;
A second core disposed radially inward of the first core and capable of contacting the outer peripheral surface of the insert component;
An insert molding apparatus comprising: a first elastic member that connects the first core and the second core and biases the first core and the second core in a direction in which the first core and the second core are separated from each other. Use
An insert molding method in which a resin molding part is integrally molded with the insert part around the insert part by injecting a resin material into the cavity in a state where the insert part is accommodated in the cavity. ,
A housing step of housing the insert part in the cavity;
A positioning step of positioning the insert part in the cavity by the positioning core;
In the positioning step, by pressing the first core toward the radial center, the second core is moved radially inward via the first elastic member, and the tip of the second core An insert molding method, wherein a surface is brought into contact with an outer peripheral surface of the insert part to hold the insert part in the cavity. A rotor manufactured using the insert molding method according to claim 6,
The insert part is a magnet;
The resin molded part is a frame part formed so as to surround the magnet,
A pair of shaft portions respectively formed on both axial end surfaces of the frame body portion and extending on a central axis of the magnet;
A rotor comprising: a gear portion formed on the shaft portion.   A motor comprising the rotor according to claim 7.   A timepiece having the motor according to claim 8.

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