JPH0295149A - Permanent magnet rotor - Google Patents

Abstract

PURPOSE:To improve the securing forces of segment magnets to a yoke by mechanically pressing to hold the magnets by a holding member coupled and held by a coupling member. CONSTITUTION:A permanent magnet rotor 1 is composed of a rotor shaft 2, a yoke 3 of magnetic material, a plurality of segment magnets 4a to 4d, a plurality of holding members 5, 5,... and two coupling members 6, 6. The members 5, 5,... are made of nonmagnetic material such as brass, aluminum, their circumferential widths are equal to the circumferential widths of recesses 4e-4h, the radial thickness is equal to the radial depth of the recesses 4e-4h, and the axial length is formed in a rectangular rod state slightly longer than that of the segment magnet. Coupling holes 6e, 6e to be engaged with the protrusions 5e, 5e of the member are formed at the positions of equal distances from the center and at equal intervals circumferentially at the members 6, 6, and an insertion hole 6f for inserting a rotor shaft 2 is formed at the center. Thus, the securing strength of the segment magnets to the yoke can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a permanent magnet rotor using segment magnets in the rotor, which is suitable for an internal rotor brushless motor in which a stator surrounds a rotor.

[Prior Art] This type of permanent magnet rotor, in which a cylindrical magnet portion is located on the outer circumferential surface, is designed to increase the magnetic force of the magnet portion or to facilitate manufacturing of the magnet portion. It is common to divide the magnet into segment magnets. 15 and 16 show a conventional permanent magnet rotor, in which a cylindrical yoke B is fixed to the outer periphery of the rotor shaft A by press fitting or adhesive, and a plurality of segment magnets C are further attached to the outer periphery of the yoke B. is fixed in a cylindrical shape by adhesive. This is used as a rotor with a rotation speed of approximately several thousand r'pm.

[Problem to be solved by the invention] As mentioned above, the segment magnets of the conventional permanent magnet rotor are
The centrifugal force caused by rotation was borne only by the adhesive force.

By the way, in recent years, brushless motors have been required to be smaller and have higher output, and the rotation speed of the rotor has also increased to 10,000 rpm.
There is a demand for high speeds exceeding 100%, and use at high temperatures is also required. In response to these demands, in conventional permanent magnet rotors, the centrifugal force acting on the segment magnets increases during high-speed rotation, and as the temperature increases, the adhesive strength decreases, resulting in the adhesive parts peeling off and the segment magnets scattering. There is a problem with this. As a result of experiments conducted by the applicant, a permanent magnet rotor with a diameter of 28 mm was heated to 120°C.
When rotated at 200 rpm, the segment magnets were separated at their adhesive points and scattered.

The present invention was made in view of the above reasons, and its purpose is to improve the adhesion force (resistance to centrifugal force) between the segment magnet and the yoke, thereby meeting the requirements for use at high temperatures and high speed rotation. Our goal is to provide a permanent magnet rotor that can accommodate these needs.

[Means for Solving the Problems] In order to solve the problems, the permanent magnet rotor 1 according to claim (1) has a rotor shaft 2 and a cylindrical shaft disposed on the outer periphery of the rotor shaft. In a permanent magnet rotor consisting of a yoke 3 and a plurality of segment magnets 4a to 4d arranged in a cylindrical shape around the outer periphery of the yoke, the circumferential width and radial thickness are sufficiently smaller than the segment magnets, and the axial direction A plurality of rod-shaped holding members 5, 5 whose length is slightly longer than the segment magnets; and a coupling member 6, which is disposed at both ends of the segment magnets and connects and holds the portions of the holding members that protrude from both ends of the segment magnets. 6, and the holding member 5. '5. −
is configured to press and hold the segment magnets 4a to 4d radially inward.

Further, in the permanent magnet rotor according to claim (2), the holding member 5
,5. -... is located on the outer periphery of the segment magnet.

Further, the permanent magnet rotor 1 according to claim (3) has holding members 5, 5. - is located approximately in the middle of the radial thickness of the segment magnet.

[Function] The permanent magnet rotor 1 according to claim (II) includes a coupling member 6.
Since the holding members 5 and 5° connected and held by 6 mechanically press and hold the segment magnets 4a to 4d reliably, the adhesion force between the segment magnets and the yoke (resistance to centrifugal force)
can be improved.

In the permanent magnet rotor 1 according to claim (2), the above-mentioned effects are more reliable, and each member can be easily manufactured and assembled.

The permanent magnet rotor 1 according to claim (3) is characterized in that the permanent magnet rotor 1 according to claim (1)
In addition to exhibiting the effect described in , - the circumferential direction of the outer circumferential surface of the segment magnet is not restricted.

[Example] Hereinafter, a first example of the present invention will be described based on FIGS. 1 to 4.

The permanent magnet rotor 1 includes a rotor shaft 2, a cork 3 made of magnetic material, a plurality of (four in this embodiment) segment magnets 4a to 4d, a plurality of holding members 5, 5, and two coupling members 6.
．． It consists of 6.

The yoke 3 is made of a magnetic material such as SK, and is molded into a cylindrical shape with an axial length shorter than the rotor shaft 2, and is fixed to the intermediate portion of the rotor shaft 2 by press-fitting, adhesive, or the like.

The segment magnets 4a to 4d have an axial length equal to that of the yoke 3.
It is molded into a curved plate shape with approximately the same length and approximately 1/4 circumference. More specifically, each segment magnet 4a to 4
The outer circumferential surfaces of both ends in the circumferential direction of d are the holding members 5, 5.d, which will be described later.
-. is cut out so that it fits almost exactly, and therefore has a step D. As a result, when the segment magnets 4a to 4d are arranged in a cylindrical shape, four recesses 4e to 4h are formed. Also, each segment magnet 4a
4d to 4d are magnetized in the radial direction, arranged in a cylindrical shape and bonded to the outer periphery of the yoke 3 so that different polarities appear alternately on each surface.

Holding members 5, 5. - is made of a non-magnetic material such as brass or aluminum, and the circumferential direction is approximately equal to the circumferential direction of each recess 4e to 4h, so it is sufficiently smaller than the segment magnet, and the radial thickness is also equal to that of each recess 4e to 4h. It is formed into a rectangular rod shape, which is approximately equal to the radial depth of 4h, and therefore about half the length of the segment magnet, and whose axial length is slightly longer than the segment magnet. Further, in the axial direction, the protrusions 5e, 5e protruding from both ends of the segment magnet have a stepped shape with the outer peripheral side cut off.

The coupling member 6.6 is also made of a non-magnetic material such as brass or aluminum and is formed in the shape of a disk with an outer diameter equal to the segment magnet. Further, at positions equidistant from the center and equally spaced in the circumferential direction, coupling holes 6e, 6e into which the protrusions 5e, 5e of the holding member are fitted are provided, and an insertion hole 6f through which the rotor shaft 2 is inserted is provided in the center, respectively. It is.

To assemble such a permanent magnet rotor l, the yoke 3 is first press-fitted or glued onto the rotor shaft 1, then the segment magnets 4a to 4d are glued to the outer periphery of the yoke 3, and then the holding members 5 are placed in each recess 4e to 4h. , 5°, and the protrusions 5e, 5e of the holding member are fitted and fixed into the coupling holes 6e, 6e of the coupling member, and the coupling member 6.6 is bonded and fixed to both end surfaces of the yoke 3 by adhesive or the like. . As a result, the holding member 5
．． 5. -m- mechanically reliably presses and holds D at the stepped portion of the segment magnet. Further, the holding members 5, 5.
- The outer circumferential surface of - is located inside the circumference formed by connecting the outer circumferential surfaces of the segment magnets.

Next, a second embodiment of the present invention will be described based on FIGS. 5 to 7. Note that members that are substantially the same as those in the first embodiment are given the same reference numerals, and detailed explanations will be omitted.

The difference from the first embodiment is that the segment magnet 4
They have shapes from a to 4d. That is, each segment magnet 4
a to 4d are recesses 4e to 4h on the outer peripheral surface at the center in the circumferential direction.
is formed. Therefore, the stepped portion is formed by a single segment magnet.

This thing has holding members 5, 5 between adjacent segment magnets.
．． - does not exist, so there is no section where the magnetic flux density is zero at the point where the N pole or S pole switches, and if it is applicable to a brushless motor, the permanent magnet rotor can be used as a magnet for position detection. Become.

Next, a third embodiment of the present invention will be described based on FIGS. 8 to 10. In this case as well, members that are substantially the same as those in the first embodiment are given the same reference numerals, and detailed explanations will be omitted.

The difference from the first embodiment is that the segment magnet 4
This is the position where the shapes a to 4d and the holding members 5 and 5 degrees are arranged. That is, each of the segment magnets 4a to 4d has a rectangular cutout approximately at the center of its circumferential end surface, and when each segment magnet is arranged in a cylindrical shape, a rectangular through hole 4j is formed by the cutout portions of adjacent segment magnets. ~4m
(corresponding to the recesses 4e to 4h in the first embodiment) are formed. Therefore, the peripheral wall near the center forming the through holes 4j to 4m becomes a stepped portion.

This thing has holding members 5, 5 on the outer peripheral surface of the segment magnet.
．． Since there is no -, the entire outer peripheral surface can be used effectively, and since there is no holding member 5.5 in the center of the segment magnet, the flow of magnetic flux is not obstructed.

Next, a fourth embodiment of the present invention will be described based on FIGS. 11 to 13. In this case as well, members that are substantially the same as those in the first embodiment or the third embodiment are designated by the same reference numerals.
Detailed explanation will be omitted.

This differs from the third embodiment in that the segment magnet 4
They have shapes from a to 4d. That is, each segment magnet 4
Rectangular through holes 4j to 4m are formed in the circumferential centers of the holes a to 4d and approximately in the radial thickness thereof.

This thing has holding members 5, 5 on the outer peripheral surface of the segment magnet.
．． Since there is no -, the entire outer circumferential surface can be used effectively.

FIG. 14 shows an example in which the permanent magnet rotor of the present invention is applied to a brushless motor. In the figure, 11 is a stator, 12 is an insulating member, 13 is a coil, 14 is a housing, 15 is a bearing stand, 16 is a bearing, and 17 is a magnetic sensing element, and the components other than the permanent magnet rotor 1 have a general configuration. Therefore, detailed explanation will be omitted.

[Effects of the Invention] The permanent magnet rotor of the present invention has the following effects.

In the permanent magnet rotor according to claim (1), the holding member coupled and held by the coupling member mechanically presses and holds the segment magnets reliably, so that the adhesion force (centrifugal force resistance performance) between the segment magnets and the yoke is improved. ) can be improved.

In the permanent magnet rotor according to claim (2), the above-mentioned effects are more reliable, and each member can be easily manufactured and assembled.

The permanent magnet rotor according to claim (3) not only exhibits the effect described in claim (1), but also allows the entire outer peripheral surface to be used without being restricted in the circumferential direction of the outer peripheral surface of the segment magnet.

Therefore, according to the present invention, it is possible to obtain a permanent magnet rotor that can meet the requirements of high-temperature and high-speed rotation.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view showing a first embodiment of the present invention;
3 is an exploded perspective view of the main parts thereof. FIG. 4 is a perspective view of the segment magnet. FIG. 5 is an exploded perspective view showing a second embodiment of the present invention. 6 is an overall perspective view thereof, FIG. 7 is a perspective view of the segment magnet, FIG. 8 is an exploded perspective view showing a third embodiment of the present invention, and FIG. 9 is an overall perspective view, FIG. 10 is a perspective view of the segment magnet, FIG. 11 is an exploded perspective view showing a fourth embodiment of the present invention, FIG. 12 is an overall perspective view, and FIG. 13 is a perspective view of the segment magnet. 14 is a longitudinal sectional view of an electric motor to which the present invention can be applied, FIG. 15 is an exploded perspective view of a conventional example, and FIG. 16 is an overall perspective view thereof. 1 - Permanent magnet rotor; 2 - Rotation Child shaft, 3- Yoke, 4a to 4d- Segment magnet, 4e to 4h recess, 4
j to 4m - through hole, D - step, 5.5m - holding member, 5e, 5e - - protrusion 6.6 - - coupling member, 5e
, 5e-binding hole.

Claims (3)

[Claims] (1) In a permanent magnet rotor consisting of a rotor shaft, a cylindrical yoke arranged around the outer periphery of the rotor shaft, and a plurality of segment magnets arranged cylindrically around the outer periphery of the yoke, the circumference a plurality of rod-shaped holding members whose direction width and radial thickness are sufficiently smaller than the segment magnets, and whose axial length is slightly longer than the segment magnets; A permanent magnet rotor further comprising: a connecting member that connects and holds portions protruding from both ends of the permanent magnet rotor, and the holding member presses and holds the segment magnets radially inward. (2) The permanent magnet rotor according to claim (1), wherein the holding member is located on the outer periphery of the segment magnet. (3) The permanent magnet rotor according to claim 1, wherein the holding member is located approximately in the middle of the radial thickness of the segment magnet.