JPS6311895Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) The present invention is intended to easily improve the accuracy of the arrangement position of the position detection element that detects the position of the field permanent magnet of the rotor. Regarding brushless motors.

(Prior Art) As shown in FIG. 4, a conventional brushless motor consists of a stator 20 and a rotor 22 having a permanent magnet 21. The second cylindrical bobbins 24 and 25 are arranged to be aligned in the axial direction, and the cylindrical stator yoke 26 is inserted so as to span between them, and is formed at the tip of each cylindrical bobbin 24 and 25. The stator yoke 26 is clamped and fixed from both ends between the protruding winding frame portions 24a and 25a. The reason why the bobbin is divided into two parts is that the stator yoke 26 is a ferrite core and its axial dimensions vary widely. This is because it may become impossible to intervene.

(Problem to be Solved by the Invention) However, in the above-mentioned two-piece bobbin, the axial arrangement position of each bobbin 24, 25 changes depending on the variation in the axial dimension of the stator yoke 26. It has its drawbacks. Conventionally, a substrate 27 is provided integrally with such a bobbin, and a position detection element 28 for detecting the position of the field permanent magnet 21 of the rotor 22 is arranged on the substrate 27. The facing distance between the permanent magnet 21 and the stator yoke 26 changes greatly due to variations in the axial dimensions of the stator yoke 26, making it impossible to obtain a stable position detection function, causing a shift in the energization phase of the stator coil 23, and causing torque unevenness. It has the disadvantage that it can cause problems.

The present invention was developed to eliminate the above-mentioned drawbacks, and its purpose is to increase the facing distance between the permanent magnet for the field of the rotor and the position detection element, regardless of the variation in the axial dimension of the stator yoke. The purpose is to provide a brushless motor that can be set precisely.

[Structure of the invention] (Means for solving the problem) In the brushless motor according to the invention, the bobbins for winding the stator coil are arranged in such a manner that they overlap inside and outside and are in contact with each other in the axial direction. It consists of an inner cylinder bobbin and an outer cylinder bobbin. A coil-shaped stator yoke having elasticity in the axial direction is interposed between the inner and outer overlapping portions of both bobbins, and both ends of this stator yoke are in contact with the radially rising portions of the above-mentioned bobbins. A substrate for arranging a position detection element is provided on one of the bobbins.

(Function) The axial dimension of the bobbin for winding the stator coil, which consists of an inner cylinder bobbin and an outer cylinder bobbin, is always kept constant by abutting each other in the axial direction. In addition, since the stator yoke interposed between the inner and outer overlaps of both bobbins can be elastically expanded and contracted in the axial direction, there is no possibility that the axial dimensions of the bobbins will be affected at all even if there are variations in the axial dimensions. do not have. Therefore, it is possible to prevent the distance between the position detection element disposed on one of the bobbin sides and the permanent magnet on the rotor side from changing due to variations in the axial dimension of the stator yoke.

(Example) The following is an example of the present invention in Figures 1 to 3.
This will be explained with reference to the figures. In Figure 1, 1
1 is a base portion formed by integrally projecting a bearing tube portion 2, and a cylindrical case 3 is attached and fixed to this base portion so as to surround the bearing tube portion 2. Reference numeral 4 denotes a rotating shaft that passes through the bearing cylinder portion 2 and is rotatably supported via bearings 5, 5.
and a pulley 7 are fixed. The above rotor 6
The rotor yoke 8 is composed of a bottomed cylindrical rotor yoke 8 located inside the case 3, and permanent magnets 9 for a field arranged on the inner peripheral surface of the rotor yoke 8 at a predetermined pitch. 10 is a stator;
In this stator 10, reference numeral 11 denotes an inner cylindrical bobbin that is fixed to the outer periphery of the bearing cylinder part 2 in an inserted state by screwing or the like, and as shown in FIG. It is formed by integrally forming a plurality of winding frame portions 12 having a shape, and a substrate 13 is integrally provided at the upper end so as to face the end surface of the permanent magnet 9. A position detection element 14 made of a Hall element facing the end face of the permanent magnet 9 is provided on this substrate 13 together with a signal processing circuit component 15. Reference numeral 16 denotes a stator yoke, which has a coil shape that can be elastically expanded and contracted in the axial direction, as shown in FIG. 2, and is inserted into the outer periphery of the inner cylinder bobbin 11. As shown in FIG. 3, 17 is an outer cylindrical bobbin having a plurality of winding frame portions 18 formed at the lower end in the figure.
It is attached by insertion so as to fit tightly onto the outer periphery of 6. As a result, the inner cylinder bobbin 11 and the outer cylinder bobbin 1
7 are overlapped in and out via the stator yoke 16, and the upper end of the outer cylinder bobbin 17 in the figure comes into contact with a part of the inner cylinder bobbin 11, for example, the winding frame part 12, and the bobbins 11 and 17 are mutually overlapped. The axial dimensional relationship is made constant. As shown in FIG. 2, the stator yoke 16 is slightly tensioned in its natural state, and is interposed in a compressed state between the inner and outer cylindrical bobbins 11 and 17, and both ends of the stator yoke 16 are connected to the radially rising portion of each bobbin, such as the winding frame portion. 12 and 18 and are fixed between the outer periphery of the inner cylinder bobbin 11 and the inner periphery of the outer cylinder bobbin 17. Reference numeral 19 denotes a stator coil wound between the two winding frames 12 and 18 as shown by the two-dot chain line in FIG. It is designed to be switched by detecting the

According to this brushless motor configured as described above, the axial dimension of the bobbin for winding the stator coil, which is composed of the inner cylinder bobbin 11 and the outer cylinder bobbin 17, is such that the bobbins 11 and 17 are mutually arranged in the axial direction. By being in contact with each other, the dimensions are always kept constant, and in this case, even if there is a large variation in the axial dimension of the stator yoke 16 due to manufacturing, the stator yoke 16 is coiled and the axial dimension is kept constant. Since the inner cylinder bobbin 11 and the outer cylinder bobbin 17 can be expanded and contracted, the mutual axial dimensional relationship between the inner cylinder bobbin 11 and the outer cylinder bobbin 17 can be set as desired without being affected by the axial size of the stator yoke 16. As a result, the facing distance between the position detection element 15 on the substrate 13 provided on either bobbin and the permanent magnet 9 will not be changed due to variations in the axial dimension of the stator yoke 16, and will remain as expected. It can be set as follows. Therefore, the position detection effect is stable, there is no deviation in the energization phase, and there is no need to provide a highly sensitive position detection element in consideration of variations in the facing distance. In addition, since the stator yoke 16 has elasticity in the axial direction, the inner and outer cylinder bobbins 11 and 17
It is also possible to prevent rattling in the axial direction during polymerization.

[Effects of the invention] As described above, the present invention provides a brushless motor in which the opposing distance between the field permanent magnet of the rotor and the position detection element can be set with high precision regardless of the variation in the axial dimension of the stator yoke. can be provided.

[Brief explanation of the drawing]

Fig. 1 is a side view showing an embodiment of the present invention in a left half section, Fig. 2 is a perspective view of the stator yoke;
FIG. 3 is a perspective view of the bobbin, and FIG. 4 is a view corresponding to FIG. 1 showing a conventional example. In the figure, 6 is a rotor, 9 is a permanent magnet, 10 is a stator, 11 is an inner cylinder bobbin, 13 is a substrate, 14 is a position detection element, 16 is a stator yoke, 17 is an outer cylinder bobbin, and 19 is a stator coil.

Claims (1)

[Scope of utility model registration request] In a brushless motor comprising a rotor having a permanent magnet and a stator having a stator coil whose energized phase is switched by a position detection element that detects the position of the permanent magnet of the rotor, the stator is overlapped inwardly and outwardly and in the axial direction. an inner cylindrical bobbin and an outer cylindrical bobbin, which are disposed in contact with each other and have a winding frame portion formed at their respective tip portions for winding the stator coil between the two; and the inner cylindrical bobbin. a coil-shaped stator yoke having elasticity in the axial direction, interposed between the outer periphery of the outer cylindrical bobbin and the inner periphery of the outer cylindrical bobbin so as to be fixed therebetween, and having both ends abutted against the radially rising portions of the bobbins; A brushless motor comprising: a substrate provided on one of the bobbins and on which the position detection element is disposed.