JPH0229824Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a permanent magnet stepping motor, in particular, an intermediate yoke that can be positioned easily with high precision when engaging a pair of intermediate yokes having comb-like pole teeth constituting a stator. It concerns York.

Conventionally, this type of stepping motor has a plurality of comb-like pole teeth 1a on the inner periphery, as shown in FIGS. 1 and 2.
an intermediate yoke 1 having equiangular pitches, and a plurality of pole teeth 2a on the inner periphery, end faces arranged such that the pole teeth 2a are located between and facing the pole teeth 1a of the intermediate yoke 1. The stator windings 3 wound in an annular manner are housed in the annular space formed by the two to constitute two sets of stators, and the pole teeth 1a and 2a A rotor 4 is disposed within the space formed.

At this time, as shown in Fig. 2, the two sets of stators are poled by the step angle of the motor (1/4 of the pole tooth pitch) by opposing the intermediate yokes 1 of the same shape back to back on opposite sides of the pole teeth 1a. It is fixed by shifting the teeth. Spot welding, caulking, etc. are common methods for this fixing.

However, these methods have the disadvantage that some kind of jig is required for positioning the two intermediate yokes 1 with respect to each other, and that it requires a lot of assembly man-hours.

The present invention eliminates this drawback by providing a hole at a predetermined position on the flat surface of the intermediate yoke and a protrusion sized to fit into the hole, thereby allowing intermediate yokes of the same shape to be engaged back to back. When,
The structure is such that the angular positions of the mutual pole teeth can be easily set to a desired step angle by fitting the respective holes and protrusions without using a jig.

Embodiment Next, an embodiment of the present invention will be described based on the drawings. Figure 3 shows one intermediate yoke 1 and end yoke 2.
This figure shows one of the stators in which the respective pole teeth 1a and 2a are arranged to face each other between the pole teeth, and a winding 3 wound annularly in an annular space is disposed.

At this time, a plurality of protrusions 1b are provided on the outer periphery of the flat surface of the intermediate yoke 1, and a notch 2b into which the protrusions 1b fit is provided in the end yoke 2,
Both pole teeth 1a and 1b are positioned.

As shown in Fig. 4, two such stators are
The intermediate yokes 1 are engaged with each other back to back, and a rotor 4 is disposed within the space formed by the pole teeth 1a and 1b to complete a stepping motor.

At this time, the pitch between the pole teeth 1a of the respective intermediate yokes 1 engaged back to back is equal to the step angle of the motor (assuming θ ₀ ), that is, 1/4 of the pole tooth pitch of one intermediate yoke 1. (or 3/4), positioning is performed by providing a protrusion 1c and a hole 1d at predetermined positions on the plane part (engaging surface) of the intermediate yoke 1.

As shown in FIG. 5, the positional relationship between the protrusion 1c, the hole 1d, and the pole tooth 1a is calculated from the arbitrary pole tooth 1a of the intermediate yoke 1 using the following formula θ ₁ +θ ₂ =4θ ₀ θ ₁ −θ ₂ = θ ₀ (
However _, θ ₀ is the step angle = 1/4 of the pole tooth pitch, and θ ₁ and _{θ 2 are} the angles between adjacent pole teeth). Protrusion 1c on one side and hole 1 on the other side at any symmetrical equiangular position θ ₃
d are provided on the same radius.

By arranging the intermediate yokes 1 of the same shape with the protrusions 1c and holes 1d in such positions facing each other back to back, the protrusions 1c of one intermediate yoke 1 fit into the holes c of the other intermediate yoke 1, respectively. Then, the angular positions of the pole teeth 1a of the intermediate yokes are determined.

For example, if the step angle is 25°, θ ₁ = 18.75° θ ₂ =
The center axis Y can be selected at a position of 11.25°. Therefore, the protrusion 1c and the hole 1d can be provided at the same angle, for example 60 degrees, from the central axis Y.

Note that the combination of the protrusion 1c and the hole 1d is not limited to one, but any number of combinations are possible. From this, the mathematical formula can also be generally expressed as θ ₁ +θ ₂ =n(4θ ₀ ) (n is an integer) θ ₁ −θ ₂ =±θ ₀ . Further, the protruding portions 1b provided on the intermediate yoke 1 may be provided on the central axis Y, or may be provided at paired positions symmetrical to the central axis Y.

The effects of using the configuration of the present invention are shown below. The conventional configuration requires a jig to position the pole teeth of the two intermediate yokes, and in the case of caulking, the intermediate yokes have concave and convex portions for caulking, so two intermediate yokes of the same shape are required. However, with this configuration, the desired angle is determined by combining two intermediate yokes of the same shape, and it is easy to assemble, reducing the number of man-hours and creating a high-precision product. be able to. Moreover, the present invention can be applied to motors of any step angle, regardless of the size of the motor, and has great industrial effects.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view of a conventional stepping motor, Fig. 2 is a perspective view of an intermediate yoke constituting the stator of the motor, and Fig. 3 is a stepping motor according to an embodiment of the present invention. FIG. 4 is a partially cutaway perspective view of the stator of the motor, FIG. 4 is a partially cutaway perspective view of the stepping motor, and FIG. 5 is a plan view of the combined surface of the intermediate yoke of the motor. 1... Intermediate yoke, 2... End yoke, 1a,
2a...pole tooth, 1c...protrusion, 1d...hole, 3...
...Stator winding.

Claims (1)

[Scope of utility model registration request] A pair of intermediate yokes having a plurality of comb-like pole teeth on the inner periphery, an end yoke having pole teeth located between the pole teeth of the intermediate yokes, and a space surrounded by the intermediate yokes and the end yokes. In the stepping motor, the intermediate yokes are fixed to each other with their pole tooth pitches shifted by a step angle, and the pair of intermediate yokes are formed in the same shape, and the pole teeth are fixed to each other by a step angle. The formula between the tooth and the pole tooth is θ ₁ + θ ₂ = 4θ ₀ θ ₁ −θ ₂ = ±θ ₀ (where θ ₀ is the step angle, θ ₁ and θ ₂ are the angles with the adjacent pole teeth, and n is an integer. )
Symmetrically with _the central axis set at θ ₁ and θ ₂ that satisfy A stepping motor is made by fitting the two into a hole and connecting the two.