JPH0130380B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a stepping motor, and more particularly to a hybrid stepping motor that effectively prevents magnetic flux leakage.

(Prior Art) In general, a hybrid stepping motor has a structure in which a coil is wound around a pole protruding from the inside of each of the four sides of a rectangular stator core, and a rotor is disposed in a space surrounded by the coil. was.

(Problems to be Solved by the Invention) In the stepping motor of the conventional structure described above, magnetic saturation occurs in the pole portions formed inside the four sides of the stator core, and in particular, magnetic flux leakage occurs in the axial direction. This has the problem of having a negative magnetic effect on equipment in which the motor is incorporated.

The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a stepping motor that can effectively prevent magnetic flux leakage due to magnetic saturation occurring at the pole portions of the stator core.

[Structure of the invention]

(Means for Solving the Problems) The present invention is a stepping motor having a stator core, four coils, a rotor, upper and lower frames, and a shield plate.

The stator core has a substantially rectangular shape, with a space formed in the center and four sides around the periphery, and a pole is formed at the inner center of each of the four sides.

Further, the rotating body has a rotating shaft.

Further, the shield plate is substantially rectangular and includes a base plate portion and a protruding piece portion, and the protruding piece portions are bent from the outside of each side of the base plate portion.

Each of the four coils is fitted into each pole of the stator core and arranged along each inner side of the four sides of the stator core, and the rotor is arranged in a space of the stator core and is connected to the upper and lower frames. are respectively fitted to the upper and lower surfaces of the stator core, the output shaft portion of the rotating shaft is made to protrude from the one frame, and the substrate portion of the shield plate is in contact with the outer surface of the one frame,
The present invention is characterized in that projecting pieces are respectively disposed on the outside of the stator core corresponding to the positions of the respective poles, and each of the projecting pieces is engaged with the other frame.

(Function) In the stepping motor of the present invention, the outside corresponding to the poles of the stator core is covered by the shield plate, and leakage magnetic flux generated at the pole portion is short-circuited.
The leakage magnetic flux concentrated on the output shaft side of the rotating shaft due to magnetic saturation generated at each pole of the stator core is prevented from leaking outward by the base plate portion of the shield plate and each protrusion portion.

(Embodiment) A stepping motor according to an embodiment of the present invention has a four-phase configuration, a step angle θ of 3 3/14 degrees, and a rotor with 28 convex portions formed at equal intervals on the circumferential surface. I will explain about it.

20 is a laminated or integrally molded stator core,
It is formed into a substantially square shape, with a space in the center and four sides 21, 21, 21, 21 formed around the periphery. At the center of the inner edge 22 of each of the four sides 21, 21, 21, 21 are poles 23, 2, respectively.
4, 25, and 26 are protruded. The height h of each of the poles 23, 24, 25, 26 is set to 0.24 to 0.5 times the outer diameter D of the rotor 27, which will be described later. , 29, 30, and 31 are each formed into a tooth shape. This first pole 23 has four convex parts 2
8, 29, 30, and 31 are evenly formed in the center of the edge 22 so as to be symmetrical with respect to the vertical center line _l1 - _l1 . Also, the second and third on the left and right
The poles 24 and 25 are arranged symmetrically with each other from the vertical center line l ₁ -l ₁ of the stator core 20.
Three convex portions 28, 29, 30, 31 are formed, and these convex portions 28, 29, 30, 31 are connected to the stator core 2.
0 by a step angle θ _° in a direction closer to the first pole 23 _side . Further, the fourth pole 26 facing the first pole 23 has four convex portions 28, 29,
30 and 31 are the third pole 2 at an angle of 2θ° which is twice the step angle θ° from the vertical center line l ₁ −l ₁
It is deviated to the 5th side. And each pole 2
3, 24, 25, 26 convex parts 28, 29, 30,
31 is formed toward the center of the stator core 20.

Next, numerals 33, 34, 35, and 36 are bobbins each having a coil 37 wound thereon, which are fitted into the respective poles 23, 24, 25, and 26 of the core 20. This first and fourth pole 2
The A-phase and phase coils 37 are wound by bi-filer winding on the bobbins 33 and 36 attached to the second and third poles 24 and 26, and the bobbins 34 and 35 attached to the second and third poles 24 and 25 are bi-filer wound. B-phase and phase coils 37 are wound in the winding. The thickness a of each bobbin 33, 34, 35, 36 is the distance between the vertical line from the tip of the opposing pole and the adjacent side edge of the pole adjacent to this pole, for example, the distance from the tip of the second pole 24. The distance b between the vertical line and the fourth pole 26 adjacent to this second pole 24 and the side edge 38 on the second pole 24 side is approximately equal, and the width c of the bobbins 33, 34, 35, and 36 is approximately equal. The inner edge 2 of each edge 21 of the stator core 20
2 from the distance d between bobbins 33, 34, 35, 36
The thickness should be approximately equal to the value obtained by subtracting twice the thickness a.

Next, the rotor 27
The rotor 27 is disposed in a space 29 surrounded by coils 37 wound around the coils 5 and 26, and the rotor 27 consists of a conical magnetic body 4 provided with a disk-shaped permanent magnet 40 sandwiched therebetween.
1, 42, and these magnetic bodies 41, 42
28 protrusions 43 are formed at equal intervals on the outer circumferential surface of the upper and lower magnetic bodies 41 and 42.
It is offset in the circumferential direction by one-half, that is, one-half of the step angle θ°.

Further, the upper side of each bobbin 33, 34, 35, 36 is provided with a bobbin 33, 34, 35, 36, respectively.
A terminal pin 64 is protruded to connect the lead wire of the coil 37 wound around the coil 37, and the terminal pin 64 is inserted into the connection hole 48 of the printed wiring board 47 and connected.

Further, terminal pins 50 of the connector 49 are connected to this wiring board 47.

Further, each pole 23, 2 of the stator core 20
Bobbins 33, 34, 3 fitted to 4, 25, 26
5, 36, for example, between the first pole 23 and the second pole 24 and the third pole
Both ends of a film-shaped slip-off prevention piece 51 are respectively locked between the fourth pole 25 and the fourth pole 26 to prevent each bobbin 33, 34, 35, 36 from falling off.

Reference numerals 52 and 53 designate motor frames, which are fitted onto the upper and lower surfaces of the stator core 20. Both frames 52 and 53 are provided with bearings 45 and 46 that rotatably support a rotating shaft 44 provided at the center of the rotor 27.

Furthermore, a holding protrusion 54 is provided on the inner surface of the lower frame 53 to engage with the inner surface of the bobbins 33, 34, 35, and 36. Note that when a straight conductor is connected to the lead wire of the coil 37 without using the wiring board 47, the inner surface of the upper frame 52 is also engaged with the inner surfaces of the bobbins 33, 34, 35, and 36, and the bobbin 33 , 34, 35, and 36 are provided in a protruding manner.

Then, the upper and lower frames 52 and 53 are fastened and fixed with bolts 55 passing through the stator core 20.

Reference numeral 56 denotes a shield plate made of a magnetic material such as an iron plate, which has a substantially square shape with each corner cut out to form a cross shape, through which the output shaft portion 57 of the rotating shaft 44 is inserted through the central portion. It has a base plate part 59 in which a hole 58 is formed, and a protrusion piece part 61 extending and bent from each protrusion part 60 formed by the cutout of this base plate part 59. An engaging piece 62 is formed in a bent manner at the tip of the engaging piece 62 except for one protruding piece 61 . The substrate portion 5 of this shield plate 56
9 is brought into contact with the outer surface of the lower frame 53, and each protruding piece 61 is attached to the outer circumferential surface of the upper and lower frames 52, 53 and the outer circumferential surface of the stator core 20.
The engagement piece engages with the engagement groove 63 formed corresponding to the positions of 4, 25, and 26, and is engaged with the engagement groove 63 formed on the upper outer periphery of the upper frame 52 except for the position of the connector 49. The part 62 is locked, and the pole 2
In the 3, 24, 25, and 26 parts, magnetic leakage due to magnetic saturation is prevented, especially on the output shaft part 57 side.

Next, the operation of this embodiment will be explained.

First, when the A phase of the coils 37, 37 attached to the first pole 23 and the fourth pole 26 are excited, for example, the first pole 23 becomes the S pole,
The fourth pole 26 becomes the N pole, and the first pole 26
3 includes a convex portion 43 of one magnetic body 41 of the rotor 27.
is attracted, and the convex portion 43 of the other magnetic body 42 of the rotor 27 is attracted to the fourth pole 26, rotated by a step angle θ°, and then attached to the second pole 24 and the third pole 25. When the B phase of the coils 37, 37 are excited, the second pole 24 becomes the N pole, the third pole 25 becomes the S pole, and the second pole 24 has the other magnetic body 42 of the rotor 27. The convex portion 43 is attracted and the rotor 27 is attached to the third pole 25.
The convex portion 43 of one of the magnetic bodies 41 is attracted, the rotor 27 rotates θ°, and then, when the phases of the coils 37, 37 of the first pole 23 and the fourth pole 26 are excited, the first Pole 23 becomes the N pole, and the fourth
The pole 26 becomes the S pole, the first pole 23 attracts the convex part 43 of the other magnetic body 42 of the rotor 27, and the fourth pole 26 attracts the convex part 43 of the other magnetic body 41 of the rotor 27. When the part 43 is attracted and rotated by a step angle θ°, and the phases of the coils 37, 37 of the second pole 24 and the third pole 25 are energized,
The second pole 24 becomes the south pole, and the third pole 2
5 becomes the N pole, and the rotor 2 is attached to the second pole 24.
The convex portion 43 of one of the magnetic bodies 41 of the rotor 27 is attracted, and the other magnetic body 42 of the rotor 27 is attracted to the third pole 25.
The convex portion 43 of is attracted, the rotor 27 rotates θ°,
This operation is repeated and the rotor 27 is rotated in steps.

The leakage magnetic flux concentrated on the output shaft portion 57 side of the rotating shaft 44 due to magnetic saturation occurring in each pole 23, 24, 25, and 26 is prevented from leaking by the base plate portion 59 of the shield plate 56 and each protrusion portion 61. Prevented.

When assembling, each bobbin 33, 34,
By inserting the terminal pins 64 protruding from the terminal pins 35 and 36 into the connection holes 48 of the printed wiring board 47 and connecting them by soldering, the bobbins 33, 34, 35, and 36 are held in position, and wiring can be easily performed.
There is no risk of incorrect wiring and connection failures can be prevented. Furthermore, by connecting the connector 49 to the wiring board 47, external conductor wires can be connected reliably.

In addition, each pole 23, 24 of the stator core 20,
A bobbin 33 with a coil 37 wound around 25 and 26,
When winding the bobbins 34, 35, and 36, two bobbins to be attached to the bobbins facing each other are inserted into the spaces between the respective poles 23, 24, 25, and 26, and each bobbin is wound by moving the bobbins in opposite directions. Can be fitted to a pole.

〔Effect of the invention〕

According to the present invention, a shield plate is disposed on the outer surface of one side from which the output shaft portion of the rotating shaft protrudes among the frames disposed on both sides of the stator core,
This shield plate includes a base plate that comes into contact with the outer surface of the frame on one side, and a projecting piece that extends from the base plate along each pole corresponding to the position of the poles of the stator coil and engages with the frame on the other side. Since the pole part of the stator core is covered with a shield plate, the leakage magnetic flux generated in the pole is short-circuited.
In particular, leakage magnetic flux concentrated on the output shaft side is prevented by the projecting piece of the shield plate, which prevents the effects of leakage magnetic flux on equipment in which the motor is installed, and the shield plate can be easily installed. be.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a stepping motor showing an embodiment of the present invention, FIG. 2 is a partially cutaway front view of the stepping motor, FIG. 3 is a bottom view with the lower frame removed, and FIG. FIG. 4 is a plan view of the stator core, and FIG. 5 is a perspective view of the shield plate. 20... Stator core, 21... Four sides, 22
...edge, 23, 24, 25, 26...pole,
27... Rotor, 37... Coil, 39... Space, 44... Rotating shaft, 52, 53... Frame,
56... Shield plate, 57... Output shaft section, 59...
...Base part, 61... Protruding piece part.

Claims (1)

[Claims] 1. A stator core 20, four coils 37,
The stepping motor has a rotor 27, upper and lower frames 52, 53, and a shield plate 56, and the stator core 20 is approximately rectangular, with a space 39 formed in the center and four sides 21 formed around the periphery. There is a pole 23 at the center of the inside of the four sides 21
24, 25, and 26 are formed, respectively, the rotor 27 has a rotating shaft 44, and the shield plate 56 is approximately rectangular and has a substrate portion 59.
and a projecting piece 61, which is bent from the outside of each side of the base plate 59, and the four coils 37 are connected to each pole 23, 24, 25, 26 of the stator core 20, respectively. The rotor 27 is disposed in the space 39 of the stator core 20, and the upper and lower frames 52, 53 are fitted to the stator core 20, and are disposed along the inner sides of the four sides 21 of the stator core 20. 20 , the output shaft portion 57 of the rotary shaft 44 protrudes from the one frame 53 , and the shield plate 56 has a substrate portion 59 fitted to the one frame 53 . The protruding pieces 61 are arranged on the outer side of the stator core 20 corresponding to the positions of the respective poles 23, 24, 25, and 26, and the protruding pieces 61 are brought into contact with the other frame. 52.