JPH0832156B2 - PM type stepping motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a PM (permanent magnet) type stepping motor with an improved connection structure between a coil end and external wiring.

[Conventional technology]

For example, a PM type stepping motor with a lead screw part for moving the driven body is used as the stepping motor for moving the driven body such as a write / read head that is moved in the radial direction of the rotating floppy disk. The construction is shown in FIGS. 9 to 13.

The stator shown by reference numeral 1 in FIGS. 9 and 10 is formed by housing a pair of coil assemblies 2 having the same structure in a motor frame 3. Each coil assembly 2 is a synthetic resin bobbin 4 in which flange portions 4b are provided at both ends of a tubular body portion 4a as shown in FIGS.
And a conductive pin 6 projecting from the outer peripheral surface of one flange portion 4b in the radial direction by press-fitting on the tip end surface of a pin mounting convex portion 5 integrally formed to be wound around the body portion 4a. At the same time, the coil end 7a is formed with the coil 7 wound around and fixed to the pin 6.

The motor frame 3 is formed, for example, by abutting the opening ends of a pair of first stator yokes 8 made of a magnetic metal plate and welding the portions. The first stator yoke 8 on one side is connected to the motor mounting plate 9
Is formed by bending comb teeth as magnetic poles on the inner peripheral edge of the fixed end surface, and the other first stator yoke 8 is also formed on the inner peripheral edge of the end surface on which the motor frame end plate 10 is fixed. It is formed by bending the teeth.

Further, notches 11 are formed in the outer peripheral surface of each stator yoke 8 used as a motor frame portion from the opening thereof, and these notches 11 are continuous with each other as shown in FIG. . A second stator yoke 12 is associated with each of the first stator yokes 8. The second stator yoke 12 is made of a magnetic metal plate, and is formed by bending comb teeth as magnetic poles which are arranged between the comb teeth of the first stator yoke 8 on the inner peripheral edge thereof.

The pair of coil assemblies 2 are housed in the motor frame 3 with one flange portion 4a provided with the pin mounting convex portion 5 overlapping each other. Each coil assembly 2 is sandwiched between the stator yokes 8 and 12, and the inner peripheral surface thereof is covered with the comb teeth. Then, the superimposed pin mounting projections 5 of each coil assembly 2 are passed through the notches 11 as shown in FIGS. 9 and 11.

Then, outside the motor frame 3, the pin 6 is passed through a connection hole 14 provided in the printed wiring board 13, and the wiring pattern 15 of the board 13 and the pin 6 are connected by soldering. The back surface of the printed wiring board 13 is designed so as to abut against the tip surface of the pin mounting convex portion 5, and an external lead wire (not shown) is connected to the wiring pattern 15.

The motor mounting plate 9 is screwed to a fixing member (not shown), and a slide bearing 16 made of a sintered alloy is mounted on the center of the motor mounting plate 9. A sliding bearing is used as the fixing member.
Bearing means is provided opposite to 16. Further, a preload spring portion 17 cut and raised on the inner surface side is provided at the center of the motor frame end plate 10.

Further, the motor shaft shown by reference numeral 18 in FIG. 9 is rotatably supported by penetrating the intermediate portion into the slide bearing 16. At the same time, the steel ball 19 fixed to one end of the motor shaft 18 is
A steel ball (not shown) that is in contact with 17 and fixed to the other end is pressed against the bearing means by the urging force of the preload spring portion 17, whereby the motor shaft 18 is restrained from axial movement and is rotatable. It is provided in.

A cylindrical rotor magnet 21 is attached to one end of the motor shaft 18 via a mold resin layer 20. The rotor magnet 21 is magnetized in multiple poles alternately in the circumferential direction, and the outer peripheral surface thereof faces a pole tooth of each of the stator yokes 8 and 12 with a slight air gap. In addition,
Motor shaft 18 with steel balls fixed on both ends, mold resin layer 20,
The rotor magnet 21 forms a rotor.

Further, a lead screw portion (not shown) is formed on the other end of the motor shaft 18. A moving body (not shown) is screwed into the screw portion while restraining its rotation, and a fed body such as a read / write head is supported by the moving body. Therefore, the rotation of the rotor allows the lead screw unit to move the moving body along the axial direction of the motor shaft 18.

[Problems to be solved by the invention]

According to the above-mentioned conventional configuration, when the coil end 7a portion entwined with the pin 6 is gathered up to form a ball larger than the connection hole 14, that portion serves as a stopper, as shown in FIG. As shown, the printed wiring board 13 is separated from the tip end surface of the pin mounting convex portion 5, and the printed wiring board 13 is displaced from the standard position. further,
As the printed wiring board 13 is pushed in the direction of arrow A in FIG. 13 and is abutted against the tip end surface of the pin mounting protrusion 5, the tip end side of the coil end 7a is entangled with the pin 6 as shown in FIG. As a result, the coil end 7a, which is completely in the tension state and is directed toward the pin 6, has a connection hole 14 shown in FIG.
Since the hole edge 14a of the above is hit, there is a problem that the coil end 7a may be disconnected due to it.

Further, in the conventional configuration, the printed wiring board 13 is connected to the pin 6 by soldering, but the pin 6 is only attached to the pin attachment convex portion 5 by press fitting. Therefore, when a strong external force acts on the printed wiring board 13 in the direction of arrow B in FIG. 9 during handling of the motor, the printed wiring board 13 and the pins 6 may come off from the pin mounting protrusions 5. there were.

Moreover, in the conventional configuration, no means is provided for restricting the positions of the pin mounting projections 5 of the pair of coil assemblies 2 that are superposed on each other, so that the axis of the pin mounting projections 5 and the width of the notch 11 are Due to the play based on the dimensional difference, the pin mounting projections 5 individually move, and the positional relationship between the pins 6 protruding from them is not maintained constant. Therefore, the positional relationship between the pins 6 and the connection holes 14 of the printed wiring board 13 may be misaligned, and the work of attaching the printed wiring board 13 to the pins 6 is troublesome.

INDUSTRIAL APPLICABILITY According to the present invention, the printed wiring board can be securely mounted within the management standard position, the coil end can be prevented from being broken, and the printed wiring board can be prevented from being unintentionally detached. The purpose is to obtain a PM stepping motor that can improve the workability of mounting the board.

[Means for solving problems]

The present invention is a bobbin provided with a flange portion on each end of a tubular body, and a conductive pin projecting on a pin mounting projection formed by projecting in a radial direction on an outer surface of one flange portion, With a coil wound around the body and the coil end is wound around the pin and fixed,
A pair of coil assemblies provided by superimposing the one flange portion provided with the pin attachment convex portion are provided, and the pair of coil assemblies are housed in a motor frame, and a notch formed in the frame is provided. It is applied to a PM type stepping motor in which the wiring pattern of the board is soldered to the pin by passing the pin mounting projection through the connection hole provided in the printed wiring board outside the motor frame.

Further, in the PM type stepping motor of the present invention, the printed wiring board can be securely mounted within the management standard position, and in order to prevent disconnection of the coil end, the pin mounting convex portion is provided with a tip side portion to each other. Adjacent recesses and small protrusions are formed, the pins are provided so as to project from the bottom surface of the recesses, and the printed wiring board is butted against the tip end surface of the small protrusions.

Further, in order to prevent the printed wiring board from coming off easily, the engaging claws that face each other in the state in which the one flange portion is overlapped with each other are provided on one side of each of the pin mounting protrusions. Then, both ends of the printed wiring board may be locked to these locking claws.

Further, in order to improve the workability of attaching the printed wiring board to the pins, it is preferable that the overlapping surfaces of the above-mentioned pin attaching convex portions are formed as concave and convex surfaces and these concave and convex surfaces are fitted to each other.

[Action]

In the PM type stepping motor configured as described above, the concave portion formed at the tip end side portion of the pin mounting convex portion accommodates the coil end entwined with the pin protruding on the bottom surface and The portion abuts the front end surface thereof on the back surface of the printed wiring board to prevent the printed wiring board from reaching the inside of the recess, and regulates the mounting position of this board.

Also, the locking claws protruding from one side of each pin mounting projection are locked to both ends of the printed wiring board, and this board is brought into contact with the tip of the small projection of the pin mounting projection. Hold the state.

Furthermore, the overlapping surfaces formed by the concave and convex surfaces of the pin mounting protrusions are fitted to each other to position the pin mounting protrusions relative to each other, and the positional relationship between the pins protruding from the tip surfaces of these pin mounting protrusions is determined. Hold in a predetermined state.

〔Example〕

A first embodiment of the present invention will be described with reference to FIGS. 1 to 4. In the description, the same configurations as those of the conventional example described with reference to FIGS. 9 to 13 are denoted by the same reference numerals as those of the conventional example, and the description thereof will be omitted. Only different configurations will be described below. To do.

In this embodiment, the structure different from the conventional example is the connection structure between the coil end and the external wiring. That is, bobbin 4
In the pin mounting convex portion 31 which is integrally molded with the motor frame 3 and passes through the notch 11 of the motor frame 3, the concave portion 32 and the small convex portion 33 which are adjacent to each other are integrally formed at the tip side portion thereof. A pin 6 is provided on the bottom surface of the recess 32 by press fitting, and a coil end 7a is entwined with the pin 6 and the portion is housed in the recess 32. Also,
As in the conventional case, outside the motor frame 3, the pin 6 is passed through the connection hole 14 provided in the printed wiring board 13 and is connected to the wiring pattern 15 of this board 13 by soldering. The back surface of the printed wiring board 13 is abutted against the tip surface of the small convex portion 33.

In assembling the PM type stepping motor having such a structure, the pin 6 protruding from the pin mounting protrusion 31 is provided.
The coil end 7a of the coil is entangled at the root portion of the coil, that is, the portion located in the recess 32. After that, the pins 6 are inserted into the connection holes 14 of the printed wiring board 13, and the back surface of the board 13 is pushed until it comes into contact with the tip end surface of the small convex portion 33. As a result, the printed wiring board 13 can be positioned by the small protrusions 33. Then, while maintaining this state, the pin 6 and the wiring pattern 15 of the printed wiring board 13 are connected by soldering.

Therefore, the printed wiring board 13 can be prevented from reaching the inside of the concave portion 32 by restricting the position of the printed wiring board 13 by the small convex portion 33 as described above, so that the coil end entwined with the pin 6 inside the concave portion 32 can be prevented. 7a does not cause variation in the mounting position of the printed wiring board 13. For this reason,
The printed wiring board 13 can be accurately mounted within the control standard position, and the quality of the motor can be improved. Further, as described above, the printed wiring board 13 does not reach the inside of the recess 32 due to the stopper action of the small convex portion 33, so that the hole edge 14a of the connection hole 14 of the printed wiring board 13 contacts the coil end 7a. I won't be childish. Therefore, disconnection of the coil end 7a can be eliminated.

Next, referring to FIG. 5 and FIG.
Examples will be described.

In this embodiment, a locking claw 35 is integrally projected on the right side of the pin mounting projection 31 arranged on the upper side in FIG.
A groove 36 is formed between this and the tip surface of the small convex portion 33.
Further, a similar locking claw 35 is integrally provided on the left side portion of the pin mounting convex portion 31 arranged on the lower side in FIG. 5, and a groove is provided between this and the tip surface of the small convex portion 33. Forming 36. Each locking claw
35 is flexible and deformable by the elasticity of the molding resin of the bobbin 4, and is opposed to the left and right. The pair of coil assemblies 2 having the same structure are arranged such that one of them is reversed and overlapped with each other, whereby the locking claws 35 are provided so as to face the above-described point-symmetrical arrangement. Then, both ends of the printed wiring board 13 enter the groove 36 and are respectively locked by the pair of locking claws 35, thereby preventing the disengagement in the direction of arrow C in FIG. Also,
The configuration other than the points described above is the same as the configuration of the first embodiment, and therefore the description thereof is omitted.

Therefore, in the second embodiment, in addition to the same effects as the first embodiment, the printed wiring board 13 can be held at the predetermined mounting position by the pair of locking claws 35.
When an external force C acts on this substrate 13, the locking claw 35 causes the external force C to be applied.
It is possible to receive the force and to eliminate the concentration of the external force on the pin 6. Therefore, it is possible to prevent the printed wiring board 13 from being accidentally detached together with the pin 6 by the external force C. Incidentally, in this second embodiment, the locking claw
The 35 may be provided so as to project on the other side facing the recess 32.

In addition, in the third embodiment of the present invention shown in FIGS. 7 and 8, the overlapping surfaces of the pin mounting projections 31 are formed as uneven surfaces as shown in FIG. Are fitted together as shown in FIG. Moreover, a concave portion 32 is provided at the tip of the convex side of the fitting, that is, a portion where the thickness is increased by providing the concave and convex surface, and the pin 6 is projected there. Further, the configuration other than the points described above is the same as the configuration of the first embodiment, and therefore the description thereof is omitted.

In the third embodiment, in addition to the same effects as the first embodiment, the positional relationship between the pin mounting protrusions 31 that are overlapped with each other is determined by fitting the concave and convex surfaces. Therefore, even if the width D of the notch 11 and the width E of the pin mounting convex portion 31 are slightly varied, the pin mounting convex portion 31 is affected by the variation.
The positional relationship between the four pins 6 protruding from the pin mounting convex portion 31 can be kept constant because the positional displacement of the comers does not occur. That is, it is possible to prevent the inconvenience that the pin 6 and the connection hole 14 of the printed wiring board 13 are misaligned and the pin 6 does not enter the connection hole 14 of the printed wiring board 13. Can be facilitated. Moreover, since the wall thickness of the portion where the pin 6 is provided is thick, it is possible to eliminate the possibility that the pin mounting convex portion 31 is deformed by the heat when the pin 6 and the printed wiring board 13 are soldered. it can.

Although each of the above embodiments is configured as described above, the present invention is not limited to these embodiments. For example, the technical idea of the third embodiment may be adopted in the second embodiment. Further, the motor frame may be one having a bottomed cylindrical shape whose open end is closed by the motor mounting plate (in this case, the first and second stator yokes are both the above-mentioned second one). The same structure as the stator yoke 12 is used and the coil assembly housed in the motor frame is sandwiched. Further, the printed wiring board 13 is a board-shaped one in which the wiring pattern 15 is provided on the hard resin substrate in each of the above embodiments, but instead of this, a flexible resin substrate is provided with the wiring pattern. A so-called flexible printed wiring board may be adopted. When this substrate is adopted, the external lead wire can be omitted and the number of soldering points can be reduced, so that the occurrence rate of defective electrical connection can be reduced. Further, it is needless to say that the present invention can be applied to a PM type stepping motor used for purposes other than head driving.

〔The invention's effect〕

Since the present invention is configured as described above, it has the following effects.

In the PM type stepping motor according to claim 1, a concave portion and a small convex portion which are adjacent to each other are formed on the tip side portion of the pin mounting convex portion, and the pin is provided on the bottom surface of the concave portion, and the tip surface of the small convex portion is formed. Since the printed wiring board is brought into contact with the printed wiring board, the printed wiring board can be securely mounted within the management standard position, and disconnection of the coil end can be prevented.

Further, in the stepping motor according to a second aspect of the present invention, the locking claws that face each other in the state where the flange portions are overlapped with each other are provided so as to project from one side part of each pin mounting convex part, and the locking claws are printed. Since both ends of the wiring board are locked, the printed wiring board can be prevented from being accidentally detached.

Furthermore, in the PM type stepping motor according to claim 3, since the overlapping surfaces of the pin mounting projections are formed into uneven surfaces and these uneven surfaces are fitted together, the workability of mounting the printed wiring board on the pins is improved. Can be improved.

[Brief description of drawings]

1 to 4 show a first embodiment of the present invention, FIG. 1 is an exploded perspective view of a main portion, FIG. 2 is a vertical sectional view of the whole, and FIG. 3 is a perspective view of a coil assembly. FIG. 4 is a plan view showing a partial cross section of the main part. 5 and 6 show a second embodiment of the present invention, and FIG. 5 is an exploded perspective view of a main part, FIG.
The figure is a plan view of the main part. 7 and 8 show a third embodiment of the present invention, FIG. 7 is a perspective view of a coil assembly, and FIG. 8 is a front view of a main part. Figures 9 to 13
FIG. 9 shows a conventional example, FIG. 9 is an overall longitudinal sectional view, FIG. 10 is a partial exploded perspective view, FIG. 11 is a perspective view of a coil assembly, and FIGS. 12 and 13 show a printed wiring board. It is a top view which partially cross-sections and shows different examples of attachment failure. 2 ... Coil assembly, 3 ... Motor frame, 4 ... Bobbin, 4a ... Body part, 4b ... Flange part, 6 ... Pin, 7 ... Coil, 7a ... Coil end, 11 ... Notch, 13 ... Printed wiring board, 14 ... Connection Hole, 15 ... Wiring pattern, 31 ... Pin mounting projection, 32 ... Recess, 33 ... Small projection, 35 ... Locking claw.

Claims (3)

[Claims] 1. A bobbin in which flange portions are provided at both ends of a tubular body portion, and a conductive pin projecting from a pin mounting protrusion formed by radially projecting on the outer surface of one flange portion. A pair of coil assemblies that are wound around the body portion and have a coil end that is wound around and fixed to the pin, and that are provided by superimposing the one flange portion provided with the pin attachment convex portion. The pair of coil assemblies are housed in the motor frame, the pin mounting protrusion is passed through the notch formed in the frame, and the pin is provided in a connection hole provided on the printed wiring board outside the motor frame. In the PM type stepping motor in which the wiring pattern of this board and the pins are soldered, It is characterized in that a concave portion and a small convex portion adjacent to each other are formed on the end side portion, the pin is projectingly provided on the bottom surface of the concave portion, and the printed wiring board is abutted on the tip end surface of the small convex portion. PM type stepping motor. 2. A locking claw facing each other in the state where the one flange portion is overlapped with each other is provided by projecting on one side of each of the pin mounting projections, and the printed wiring is connected to these locking claws. The both ends of the substrate are locked.
The PM type stepping motor described. 3. The PM type stepping motor according to claim 1 or 2, wherein an overlapping surface of each of the pin mounting projections is formed as an uneven surface, and these uneven surfaces are fitted to each other.