JP2002218707A - Structure of electromagnetic actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of molding defects that are caused by deteriorated circulation of molten resin in the injection molding of a rotating body, and to enhance positional accuracy at maximal stroke of a drive shaft. SOLUTION: A passing hole 22 is formed, in which at least two stripes of female screws are tapped on is inside circumferential surface in the direction toward the inside shaft of the rotating body 21 that, made of a synthetic resin, is provided inside an electromagnetic coil 2, in such a way as to rotate freely and that has a permanent magnet 4 encased solidly in its outside circumference. The drive shaft 23, on the outside circumferential surface of which at least two stripes of male screws 12 that are engaged with the female screws are threaded, is passed and arranged inside the through-hole. As the rotating body 21 rotates, the female and male screws are engaged with each other to make the drive shaft perform linear stroke movements. A stripe of spiral clearance grooves 24, on which a stopper pin 27 provided protrusively on the driving shaft slides at stroke movement, is formed on the inside circumferential surface of the through-hole. These spiral clearance grooves allows spiral thickness to be formed on the circumferential wall of the rotating body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an electromagnetic actuator structure in which, when an electromagnetic coil is energized, the permanent magnet is rotated by a male / female screw into linear motion with the rotation of a rotating body, and the drive shaft is moved by a stroke. About.

[0002]

2. Description of the Related Art As a conventional electromagnetic actuator structure of this kind, for example, there is one shown in FIG.

[0003] In brief, an electromagnetic coil 2 provided in a cylindrical solenoid housing 1 whose one end is closed by a front cover 1a;
A rotating body 3 made of a synthetic resin material rotatably provided on the inner periphery of the rotating body 3 and integrally having a cylindrical permanent magnet 4 on the outer periphery, and a through hole 5 formed in the inner axial direction of the rotating body 3. And a drive shaft 6 that is inserted through the drive shaft 6.

[0004] The electromagnetic coil 2 includes a pair of magnetic bobbins 2a and 2b provided at the front and rear, and the magnetic bobbins 2a and 2b.
b, and coils 2c and 2d respectively wound therearound. A control current is supplied to each of the coils 2c and 2d from a control mechanism (not shown) so that the rotating body 3 is controlled to rotate forward and reverse. It has become.

The rotating body 3 is integrally formed by injection molding, and its front and rear ends are rotatably supported by ball bearings 7 and 8, and the bobbins 2a and 2b on the outer peripheral surface.
The permanent magnet 4 is fixed between the front and rear annular projections 3a, 3a at the position where 2a is located. The through hole 5
As shown in FIGS. 7 and 8, at the front end of the inner peripheral surface,
A relatively large-diameter cylindrical relief groove 9 which allows the stopper pin 13 to be moved in the axial direction, which will be described later, is formed, and two internal threads 10 are formed on the inner peripheral surface of the annular portion at the rear end. ing.

The drive shaft 6 is made of metal, and as shown in FIG. 9, a front end portion 6a is cut out from a substantially central position at a lower end of an outer peripheral surface so as to have a substantially semicircular cross section. On the other hand, on the outer peripheral surface of the rear end portion 6b, two external threads 12 which are screwed into the internal thread 10 of the through hole 5 are cut,
Thus, the stroke amount of the drive shaft 6 for one rotation of the rotating body 3 is increased. Further, the stopper pin 13 having a relatively low height is protruded near a boundary position with the rear end portion 6a of the front end portion 6a. An operating section 14 is fixed to the front end of the front end portion 6a of the drive shaft 6.

[0007] Further, at the end of the clearance groove 9, there is integrally provided a restricting portion 11 for restricting the maximum stroke position of the drive shaft 6 by contacting the stopper pin 13.

When power is applied to one of the coils 2c of the electromagnetic coil 2 from the control mechanism, the rotating body 3 rotates in one direction via the permanent magnet 4, and the male screw 12 turns the female screw 10
, The drive shaft 6 is linearly moved to the right, for example, to a position shown in the upper half of FIG. At this time, the stopper pin 13 linearly moves along the rotating relief groove 9 and restricts the further maximum stroke movement of the drive shaft 6 at a position where the stopper pin 13 abuts the restricting portion 11 in the axial direction.

When the other coil 2d is energized,
The rotating body 3 is now rotated in the reverse direction via the permanent magnet 4, and the drive shaft 6 is linearly moved leftward through the male and female screws 10 and 12 as shown in the lower half of FIG. At the position where 13 abuts against the inner surface of the front cover 1a, the maximum leftward stroke movement is restricted.

[0010]

In the above-described conventional electromagnetic actuator structure, the movement position of the drive shaft 6 at the maximum rightward stroke is regulated by the position where the stopper pin 13 abuts on the regulation portion 11. However, if the collision of the stopper pin 13 with the restricting portion 11 is continuously performed, the restricting portion 11 is worn and the maximum stroke position of the drive shaft 6 changes, and the maximum positional accuracy is reduced. There is a possibility that it will.

Therefore, it is conceivable to prevent the occurrence of abrasion by increasing the axial length of the stopper pin 13 to reduce the surface pressure in contact with the restricting portion 11. However, if the axial length of the stopper pin 13 is increased, Inevitably the escape groove 9
The entire inner diameter also needs to be made larger accordingly. Then, when the main body of the rotating body 3 is injection-molded, the peripheral wall of the clearance groove 9 must be formed sufficiently thin. In this case, however, the entire peripheral wall of the clearance groove 9 during injection molding is formed. There is a possibility that the molten resin is not sufficiently rotated, and molding defects, which are so-called short molds, are likely to occur.

[0012] In addition, 2 cut into the inner peripheral surface of the through hole 5.
The internal thread 10 of the thread also has two internal thread grooves (2
Position), and when assembling the components, if the two ends of the external thread 12 of the drive shaft 6 are screwed together with the two internal thread grooves of the internal thread 10, it may correspond. There is a possibility that the stopper pin 13 abuts on the restricting portion 11 in the axial direction near the maximum stroke position of the drive shaft 6 in the right direction. There is a possibility that an error occurs in the maximum stroke amount.

The present invention has been devised in view of the technical problems of the above-mentioned conventional electromagnetic actuator structure, and has a structure in which a sufficient axial length of a stopper pin can be obtained while securing the thickness of the peripheral wall of a rotating body. Is provided.

[0014]

According to a first aspect of the present invention, there is provided a rotating body made of a synthetic resin, which is rotatably provided inside an electromagnetic coil and has a permanent magnet integrally formed on the outer periphery thereof, and an inside of the rotating body. A through-hole formed in the axial direction and having an internal thread cut into an internal peripheral surface, a drive shaft inserted through the through-hole and having at least two external threads threaded to the internal thread on the external peripheral surface, A stopper pin that protrudes radially on a predetermined outer peripheral surface of the drive shaft and abuts on a restricting portion provided at a predetermined position of the through hole to restrict a maximum stroke position in one direction of the drive shaft; In an electromagnetic actuator structure in which the rotating body is rotated forward and reverse by energizing control of a coil, and a drive shaft is moved in a linear direction by screwing rotation of the female screw to a male screw, the drive shaft is provided on an inner peripheral surface of the through hole. It is characterized in that the stopper pins during the stroke movement to form a helical relief groove Paragraph moving.

Therefore, according to the present invention, the escape groove is formed not in a columnar shape on the inner peripheral surface of the through hole but in a spiral shape, so that the thickness of the peripheral wall at this portion is reduced to thereby reduce the stopper. The axial length of the pin can be increased, and the thickness of the spiral peripheral wall at the side of the escape groove can be increased. Therefore, the occurrence of a short mold at the time of injection molding can be prevented.

[0016] According to a second aspect of the present invention, the restricting portion includes:
The stopper pin is formed so as to contact the terminal position of the clearance groove from the rotation direction of the rotating body.

According to the present invention, when the drive shaft is inserted into the through-hole and assembled, the stopper shaft is engaged with the helical escape groove so that the drive shaft is inserted into the through-hole in the rotational direction. Positioning can be performed. For this reason, when the one male screw side of the two male threads is screwed into one female screw of the through-hole to perform positioning in the rotational direction as in the related art, a restriction portion at the time of the maximum stroke movement of the drive shaft is likely to occur. The occurrence of an error in the contact position of the stopper pin with respect to the above can be prevented.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the electromagnetic actuator structure according to the present invention will be described in detail with reference to the drawings.

That is, this electromagnetic actuator structure comprises a cylindrical solenoid housing 1 whose one end is closed by a front cover 1a, a cylindrical electromagnetic coil 2 provided in the solenoid housing 1, A rotating body 21 made of synthetic resin, which is rotatably provided on the inner circumference of the body and has a cylindrical permanent magnet 4 integrally on the outer circumference.
And a through hole 22 formed in the inner axial direction of the rotating body 21.
And a drive shaft 23 inserted through the through hole 22.

The electromagnetic coil 2 includes a pair of magnetic bobbins 2a and 2b provided in front and back, and the magnetic bobbins 2a and 2b.
b, and coils 2c and 2d respectively wound therearound, and a control current is supplied to each of the coils 2c and 2d from a control mechanism (not shown), thereby controlling the rotating body 3 to rotate forward or reverse. It is supposed to.

The rotary body 21 is formed by injection molding, and its front and rear ends are rotatably supported by ball bearings 7 and 8, and the bobbins 2a and 2b on the outer peripheral surface are located as shown in FIG. Annular protrusion 21 at front and rear position
a, 21a are provided integrally with each other.
The permanent magnet 4 is fixed between 21a.

As shown in FIG. 3, the through hole 22 has a clearance groove 2 formed in the front end of the inner peripheral surface thereof to allow a stopper pin 27, which will be described later, to move in the axial direction with the rotation of the rotating body 21.
4 are formed, and two female threads 10 are cut on the inner peripheral surface of the annular portion 25 at the rear end.

The relief groove 24 is formed by cutting out a single spiral and extending from one end opening of the through hole 22 to the annular portion 2.
5, the inner diameter d of which is slightly larger than the inner diameter of the conventional clearance groove, and changes the thickness of the rotating body 21. That is, the through hole 22 has an inner diameter d1 on the front end side thereof originally set to be smaller than the inner diameter of the conventional escape groove, and the wall thickness of the peripheral wall thereof is set relatively large. Although the thickness of the peripheral wall of the portion 21b where the groove is formed is thin,
The thickness of the peripheral wall of the portion 21c between them is formed to be larger than the thickness of the conventional peripheral wall of the escape groove. Further, at the rear end of the clearance groove 9, a regulating portion 26 with which a stopper pin 27 abuts from the rotation direction is integrally provided.

The drive shaft 23 is made of metal.
As shown in the figure, the front end portion 23a is formed in a substantially semicircular cross section by cutting out the lower end portion of the outer peripheral surface from the substantially center position, while the through hole 22 is formed in the outer peripheral surface of the rear end portion 23b.
The two external threads 12 that are screwed into the internal threads 10 are cut. Further, a stopper pin 27 is protrudingly provided near a boundary position between the front end portion 23a and the rear end portion 23b.
The stopper pin 27 has a shaft shape, and the shaft length L is set longer than the conventional shaft length. The operating section 14 is fixed to the tip of the front end portion 23a.

When power is supplied from the control mechanism to the coil 2b on one side via the terminal 29 of the connector, the rotating body 21 rotates in one direction via the permanent magnet 4, and the male screw 12 is connected to the female screw 10. By rotating while screwing,
For example, the drive shaft 23 is linearly moved to the right as shown in the upper half of FIG. At this time, the stopper pin 27 moves linearly along the helical shape of the clearance groove 24 that rotates with the rotation of the rotating body 21, and at a position where the stopper pin 27 abuts on the restricting portion 26 in the rotation direction, the drive shaft further increases. 23
The maximum rightward stroke movement is restricted.

When the coil 2b on the other side is energized, the rotating body 21 rotates in the reverse direction via the permanent magnet 4 this time, and drives the drive shaft 23 via the male and female screws 10 and 12 in the lower half of FIG. As shown in (5), the stroke is linearly moved to the left, and the maximum leftward stroke is restricted at the position where the stopper pin 27 abuts against the inner surface of the front cover 1a.

Therefore, in particular, the two male and female threads 10, 1
2 allows the stroke of the drive shaft 23 per rotation of the rotating body 21 to be increased, and of course, by forming the escape groove 24 in a spiral shape,
Can be sufficiently reduced during the injection molding.

That is, as described above, the thickness of the peripheral wall of the rotating body 21 is relatively thick at the spiral part 21c on the side 21b where the relief groove 24 is formed, so that the molten resin during injection molding is relatively thick. Of the entire cavity is good, so that the occurrence of molding defects can be sufficiently prevented. In particular, since the relief groove 24 is spiral, the molten resin injected from the front end side of the rotating body 21 is guided spirally and flows quickly, so that the resin around each part is rotated. It will be even better. As a result, the occurrence of molding defects can be more effectively prevented.

Further, when the drive shaft 23 is inserted into the through hole 22 and assembled, first, the stopper pin 27 is engaged with the end of the spiral relief groove 24, and the spiral shape of the relief groove 24 is maintained as it is. When the drive shaft 23 is inserted while being rotated along the axis, the drive shaft 23 can be positioned in the through hole 22 in the rotational direction. For this reason, the restricting portion which is likely to be generated in the conventional erroneous assembly, that is, when the one male thread 12 of the two male threads 12 is screwed into the one female thread 10 of the through hole 22 to perform the positioning in the rotational direction, is used. An error in the contact position of the stopper pin 27 with respect to the stopper pin 25 can be prevented beforehand. Therefore, it is possible to prevent an error from occurring at the left and right maximum stroke positions of the drive shaft 23.

The depth of the clearance groove 24 can be set sufficiently large as described above, so that the axial length L of the stopper pin 27 can be increased. The surface pressure at the time of contact with the regulating portion 26 can be reduced. For this reason, the occurrence of wear of the regulating portion 26 can be prevented, and from this point also, the maximum stroke position accuracy of the drive shaft 23 can be increased.

The present invention is not limited to the configuration of the above-described embodiment. For example, the shape and size of the stopper pin 27 can be changed.
The width of the escape groove can be freely changed according to the outer diameter of the stopper pin 27.

[0032]

As is apparent from the above description, claim 1
According to the invention described in the above, instead of forming the escape groove in a cylindrical shape on the inner peripheral surface of the through hole, by forming a spiral shape,
By reducing the thickness of the peripheral wall at this portion, the axial length of the stopper pin can be increased, and the spiral peripheral wall at the side of the clearance groove can be formed to have a large thickness. For this reason, it is possible to prevent the occurrence of molding defects during injection molding due to the fact that substantially the entire peripheral wall becomes thinner as in the related art. In particular, since the relief groove is formed in a spiral shape, the molten resin at the time of injection molding passes through the spiral passage other than the relief groove, so that the spiral flow smoothly flows and the resin circumference becomes good as a whole. . As a result, occurrence of molding failure can be more effectively prevented.

According to the second aspect of the present invention, when the drive shaft is inserted into the through hole and assembled, first, the drive shaft is rotated into the through hole by engaging a stopper pin with the spiral groove. Direction can be determined,
It is possible to prevent occurrence of an error in the stopper pin contact position with respect to the restricting portion at the time of the maximum stroke movement of the drive shaft as in the related art.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of one embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a longitudinal sectional view of a rotating body provided in the embodiment.

FIG. 4 is a view taken in the direction of arrow B in FIG. 3;

FIG. 5 is a front view of a drive shaft provided in the embodiment.

FIG. 6 is a longitudinal sectional view of a conventional electromagnetic actuator structure.

FIG. 7 is a sectional view taken along line CC of FIG. 6;

FIG. 8 is a longitudinal sectional view showing a conventional rotating body.

FIG. 9 is a front view showing a conventional drive shaft.

[Explanation of symbols]

 2 Electromagnetic coil 4 Permanent magnet 10 Female screw 12 Male screw 21 Rotator 22 Through hole 23 Drive shaft 24 Escape groove 26 Restrictor 27 Stopper pin

Claims (2)

[Claims] 1. A rotating body made of synthetic resin which is rotatably provided inside an electromagnetic coil and has a permanent magnet integrally formed on an outer periphery thereof, and a rotating body formed in an inner axial direction of the rotating body and having at least two lines on an inner circumferential surface thereof. A female screw threaded through-hole, a drive shaft inserted through the through-hole and having at least two external threads threaded to the female screw on the outer peripheral surface, and a predetermined outer peripheral surface of the drive shaft. A stopper pin that protrudes in the direction, abuts a regulating portion provided at a predetermined position of the through hole, and regulates a maximum stroke position in one direction of the drive shaft. In an electromagnetic actuator structure for rotating the drive shaft in a linear direction by forward and reverse rotation and screwing the female screw to the male screw, the inner peripheral surface of the through hole has a Electromagnetic actuator structure, wherein the stopper pin to form a helical relief groove Paragraph moving. 2. The electromagnetic actuator structure according to claim 1, wherein said restricting portion is formed such that said stopper pin comes into contact with a terminal position of said clearance groove from a rotating direction of a rotating body.