DESCRIPTION

TITLE: ROTOR OF ROTARY ELECTRIC MACHINE TECHNICAL FIELD

[0001] The present invention relates to a rotor of a rotary electric machine having a plurality of magnetic poles made of, for example, permanent magnets. BACKGROUND ART

[0002] As a conventional rotor of a rotary electric machine having a plurality of magnetic poles made of permanent magnets on the outer circumference of a rotor core fixed to the outer circumference of a rotor shaft, there is known one disclosed in Japanese Unexamined Patent Publication No. 2001-25193. The rotor of the rotary electric machine disclosed in Japanese Unexamined Patent Publication No. 2001-25193 has the rotor core laminated on the outer circumference of the rotor shaft and the permanent magnets on the outer Circumference of the rotor core; and a permanent magnet scattering prevention cover made of a non-magnetic member that covers both end portions of the permanent magnets is disposed. The permanent magnet scattering prevention cover made of the non-magnetic member is fixed to the permanent magnets with adhesive.

[0003] Furthermore, as other conventional rotor of a rotary electric machine other than the aforementioned conventional rotor of the rotary electric machine, there is known one disclosed in Japanese Unexamined Utility Model Application Publication No. S55-120285. In the rotor of the rotary electric machine disclosed in Japanese Unexamined Utility Model Application Publication No. S55-120285, permanent magnets are arranged on the outer circumference of a yoke, the outer circumference of the permanent magnets is covered with a non-magnetic tubular fastening ring, and the non-magnetic tubular fastening ring is pushed to a yoke portion between the permanent magnets from the outer circumference to fix by a fastening member such as bolts.

[0004] Patent Document 1: Japanese Unexamined Patent Publication No. 2001-25193

Patent Document 2: Japanese Unexamined Utility Model Application Publication No. S55-120285
DISCLOSURE OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] In the aforementioned conventional rotor of the rotary electric machine, the rotor of the rotary electric machine disclosed in Japanese Unexamined Patent Publication No. 2001-25193 defines the circumferential position of the permanent magnets by fixing the rotor core to the permanent magnets by adhesion, or by fixing the permanent magnets to the permanent magnet scattering prevention cover by adhesion.

[0006] However, the circumferential position of the permanent magnets cannot be fixed during the time until the adhesive has cured or the adhesive does not have sufficient fixation force at the worst. The circumferential position of the permanent magnets gives a large influence on cogging torque of a motor; and therefore, in the case where the position of the permanent magnets cannot be fixed, a problem exist that the degradation and fluctuation of the cogging torque is generated.

[0007] Further, a problem exists in that there is a possibility to generate a state where the permanent magnet scattering prevention cover made of the non-magnetic member is deformed in an outer circumferential direction due to centrifugal force applied during the rotation of the rotor, the gap between a stator and the rotor is narrowed, and the rotation of the rotor is disturbed or locked.

[0008] Furthermore, in the rotor of the rotary electric machine disclosed in Japanese Unexamined Utility Model Application Publication No. S55-120285, the non-magnetic tubular fastening ring is pushed from the outer circumference; and accordingly, constriction force against the permanent magnets is generated to fix the position of the permanent magnets.

[0009] However, the fastening member such as bolts is needed; and therefore, a problem exists that it causes an increase in material cost and processing cost to increase in cost. Further, the gap between the permanent magnets needs to be more widened than the fastening member and it causes a decrease in torque in the case of the same constitution. In addition, a problem exists that axial length is increased in order to compensate the decrease in torque and accordingly it causes an increase in size and cost.

[0010] The present invention has been made to solve the problem described above, and an object of the present invention is to obtain a rotor of a rotary electric machine capable of achieving reduction in size and cost without disturbing the rotation of a rotor.

MEANS FOR SOLVING THE PROBLEMS

[0011] According to the present invention, there is provided a rotor of a rotary electric machine, which includes: a rotor core arranged on the outer circumferential side of a rotor shaft; and a plurality of magnetic poles fixed to the rotor core and circumferentiaL1y arranged on the rotor core. The rotor includes a non-magnetic ring attached by insertion to the outer circumference of the plurality of the magnetic poles and having a substantiaL1y polygonal shape in outer circumferential shape. The non-magnetic ring is configured such that the inner circumferential length L of the non-magnetic ring before assembly with respect to the length of an envelope L0 of tangent lines each between the outer circumferential surface of the magnetic pole and the outer circumferential surface of the other adjacent magnetic pole is set to 10.

ADVANTAGEOUS EFFECT OF THE INVENTION

[0012] In a rotor of a rotary electric machine according to the present invention, a non-magnetic ring is configured such that the inner circumferential length L of the non-magnetic ring before assembly with respect to the length of an envelope L 0 of tangent lines each between the outer circumferential surface of a magnetic pole and the outer circumferential surface of the adjacent magnetic pole is set to L^L0/ whereby the rotor of the rotary electric machine capable of achieving reduction in size and cost without disturbing the rotation of the rotor can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Fig. 1 is a transverse sectional view showing a rotor of a rotary electric machine according to Embodiment 1 of the present invention;

Fig. 2 is a longitudinal sectional view showing the rotor of the rotary electric machine according to Embodiment 1 of the present invention;

Fig. 3 is a partiaL1y enlarged transverse sectional view showing the rotor of the rotary electric machine according to Embodiment 1 of the present invention;

Fig. 4 is a perspective view showing a non-magnetic ring for the rotor of the rotary electric machine according to Embodiment 1 of the present invention; and

Fig. 5 is a perspective view showing the non-magnetic ring for the rotor of the rotary electric machine according to Embodiment 1 of the present invention.

[0014] Fig. 6 is a longitudinal sectional view showing a rotor of a rotary electric machine according to Embodiment 2 of the present invention;

Fig. 7 is a longitudinal sectional view showing a non-magnetic ring for a rotor of a rotary electric machine according to Embodiment 3 of the present invention; and

Fig. 8 is a longitudinal sectional view showing another example of a non-magnetic ring for the rotor of the rotary electric machine according to Embodiment 3 of the present invention.

MODE FOR CARRYING OUT THE INVENTION

[0015] Embodiment 1.

Hereinafter, a rotor of a rotary electric machine according to Embodiment 1 of the present invention wiL1 be described based on Fig. 1 to Fig. 5.

Fig. 1 is a transverse sectional view showing the rotor of the rotary electric machine according to Embodiment 1 of the present invention. Fig. 2 is a longitudinal sectional view showing the rotor of the rotary electric machine according to Embodiment 1 of the present invention. Fig. 3 is a partiaL1y enlarged transverse sectional view showing the rotor of the rotary electric machine according to Embodiment 1 of the present invention. Fig. 4 is a perspective view showing a non-magnetic ring for the rotor of the rotary electric machine according to Embodiment 1 of the present invention. Fig. 5 is a perspective view showing the non-magnetic ring for the rotor of the rotary electric machine according to Embodiment 1 of the present invention.

[0016] In these respective drawings, reference numeral 1 denotes a rotor shaft of the rotor of the rotary electric machine; and 2 denotes a rotor core arranged on the outer circumferential side of the rotor shaft 1 and is formed, for example, in a regular decagon in transverse section thereof. The rotor core 2 is fixed to the rotor shaft 1 by means such as press-fitting. 3 denotes magnetic poles (hereinafter, referred to as permanent magnets) made of, for example, permanent magnets, which are arranged on the outer circumferential side of the rotor core 2 in plural numbers, that is, n numbers (for example, 10 numbers in the drawing) via a gap of a circumferentiaL1y equal pitch and are provided with an outer circumferential surface formed in a substantiaL1y circular arc shape. Then, these permanent magnets 3 are fixed to the rotor core 2 by being bonded'to the outer circumferential surface of the rotor core 2 with adhesive.

[0017] 4 denotes anon-magnetic ring formed of, forexample, stainless steel serving as a non-magnetic material, and the non-magnetic ring 4 is attached by insertion so as to cover the outer circumferential surface of the permanent magnets 3 fixed to the outer circumferential surface of the rotor core 2. 5 denotes an end plate and the end plate 5 is fixed to an end face of the rotor core 2 by means such as caulking.

[0018] Furthermore, the non-magnetic ring 4 is a substantiaL1y polygonal shape in which contact points 10 with the permanent magnets 3 are regarded as substantiaL1y vertexes. The length of an envelope L0 of tangent lines each between the outer circumferential surface of the permanent magnet 3 and the outer circumferential surface of the other adjacent permanent magnet 3 with respect to the contour length between the contact points r nof an outer circumference portion of the permanent magnets 3 and the distance between the contact points wn of the adjacent permanent magnets 3 is expressed as the foL1owing equation.

[0019] [Equation 1]

[0020] In this case, the inner circumferential length L of the non-magnetic ring 4 before attaching by insertion to the outer circumferential surface of the permanent magnets 3, that is, before assembly with respect to the length of the envelope L0 is set to L^L0. Furthermore, the plate thickness of an abutment portion T of the permanent magnets 3 with respect to the plate thickness of other than the abutment portion T0 of the permanent magnets 3 of the non-magnetic ring 4 is set to TD of the tapered portion 23 with respect to the circumscribed circle diameter *D0 of the permanent magnets 3 is set to $D<$D.

[0033] In the thus configured non-magnetic ring 4, a portion where the inner circumferential length L is extended to L0 during assembly of the non-magnetic ring 4 is limited to the central portion 21; and therefore, putting force during the assembly of the non-magnetic ring 4 is reduced and assembly becomes easy. More particularly, the inner circumferential length L 2 of two portions of both end portions 22 of the non-magnetic ring 4 on the putting side is longer than the inner circumferential length L of the central portion 21; and therefore, putting workability is further improved. Furthermore, an excessive load is not applied to the permanent magnets 3 while fixing the position of the permanent magnets 3; and therefore, the permanent magnets 3 can be prevented from cracking and the like. In addition, the non-magnetic ring 4 can be easily put on the outer circumference of the permanent magnets 3 from the tapered portion 23 side, workability is improved, and low cost can be achieved.

[0034] Further, in the case where the length of the envelope L 0 and the inner circumferential length L 2 with respect to the circumferential length n*D 0 of the circumscribed circle diameter D0 of the permanent magnets 3 are set to L0D0), the outer circumferential diameter of the ring after putting both end portions 22 of the non-magnetic ring 4 is only increased by two times of plate thickness T with respect to $D0 while suppressing the putting force of the non-magnetic ring 4; and therefore, the gap between the rotor and a stator (not shown in the drawing) is not narrowed, assembly property of the rotary electric machine is not impaired, and the possibility of generating a state where the rotation of the rotor is disturbed and locked can be suppressed.

[10] The rotor of the rotary electric machine according to any one of Claim 1 to Claim 7, wherein said non-magnetic ring and the outer circumferential surface of said magnetic poles are fixed with adhesive.