JP3072851B2 - Permanent magnet rotor of ultra high-speed rotating machine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet rotor of a rotating machine, and more particularly to an ultra-high-speed rotating machine having a structure suitable for an ultra-high-speed synchronous machine directly connected to a turbocharger. It relates to a permanent magnet rotor.

[Prior Art] FIG. 7 shows a cross-sectional view of an example of a turbocharger direct-coupled rotating machine in which a permanent magnet rotor of a conventional rotating machine is incorporated.
The configuration of this rotating machine is such that a synchronous machine 8 is attached to a rotating shaft 6a that is directly connected to a turbine 6 that draws exhaust gas discharged from the internal combustion engine.
The permanent magnet rotor 8a, the collar 9, and the compressor 7 for supercharging the internal combustion engine are fitted and fastened with a nut 12, and the rotating shaft 6a is connected to the turbine 6 and the permanent magnet rotor 8a.
Of housing 11 by bearing 10 (10a, 10b)
Supported by

The operation of the synchronous machine 8 is such that when the synchronous machine 8 is used as a synchronous motor, the compressor 7 coaxial with the rotor 8a can be rotated. Supply can be performed arbitrarily, and the output can be improved when the internal combustion engine is running at a low speed, and black smoke can be prevented by complete combustion. When used as a generator by control, energy of exhaust gas can be recovered as electric power.

The above-described turbocharger direct-coupled rotating machine is disclosed in, for example,
As described in Japanese Patent Application Laid-Open No. 62-48931, a conventional permanent magnet rotor 8a for a synchronous machine 8 is disclosed, for example, in JP-B-63-38.
As described in Japanese Patent Publication No. 947, there are a permanent magnet provided with a strength member on the outer periphery thereof to prevent the scattering of the permanent magnet, a permanent magnet fixed on an axis of rotation with an adhesive and fixed. As described in Japanese Unexamined Patent Publication No. Sho 62-254649, there has been a structure in which a permanent magnet is incorporated in an outer cylinder with a heat insulating plate and a heat insulating cylinder sandwiched between a rotating shaft and a side plate.

[Problem to be Solved by the Invention] The above-mentioned conventional technology is, for example, a medium having a medium speed of about 50,000 to 60,000
Destruction resistance and splash resistance at low speed rotation were sufficient, but 100, 100, such as built in turbocharger
In a permanent magnet rotor that rotates at an ultra-high speed of 000 γ / min or more, an excessive centrifugal force is generated, so the outer cylinder causes permanent distortion due to centrifugal force or cracks or chipping of the permanent magnet due to expansion of the outer cylinder, In such a state, the bending rigidity of the rotor itself is low, so that the bending rigidity of the entire shaft also becomes low, and these greatly affect the change over time of the unbalance amount of the shaft system, Further, when the unbalance amount of the bearing is increased, there is a problem that the bending force of the rotating shaft is increased and the shaft may be eventually broken.

An object of the present invention is to prevent a permanent magnet incorporated in a rotor from cracking, which causes a change in the amount of unbalance of the rotating shaft system with time, and to improve the bending rigidity of the rotor, thereby improving the rigidity of the rotating shaft system. An object of the present invention is to provide a permanent magnet rotor of an ultra high-speed rotating machine capable of improving reliability.

Means for Solving the Problems In order to achieve the above-mentioned object, in the permanent magnet rotor of the ultrahigh-speed rotating machine of the present invention, the total length of the outer cylinder is shorter than the total length of the permanent magnet, and the end face of the permanent magnet is suppressed by a side plate. In order to prevent the permanent magnet from cracking, the permanent magnet is pressed into the outer cylinder to prevent cracking of the permanent magnet, and the outer cylinder is heated and expanded to insert the normal magnet at room temperature. Use a non-magnetic, high tension, high linear expansion coefficient material for the outer cylinder, and use the outer cylinder to improve the bending rigidity of the rotor. The inner periphery of the side plate is soldered and fitted to the outer periphery of the opening at both ends, so that the outer cylinder constituting the outer periphery of the permanent magnet and the side plate constituting the side surface of the permanent magnet are in a state close to an integrated structure. The structure is fixed by welding, bonding, press-fitting, or the like.

[Operation] In the permanent magnet rotor of the above-described ultrahigh-speed rotating machine, the permanent magnet is press-fitted into the outer cylinder by temperature difference press-fitting, and the permanent magnet is inserted into the heated outer cylinder by inserting the permanent magnet into the outer cylinder. There is no problem that the outer cylinder and the permanent magnet are stopped halfway, and the outer cylinder and the permanent magnet can be press-fitted satisfactorily due to the temperature difference. Since the permanent magnet is pressed into the outer cylinder in this manner, the permanent magnet is in a state of receiving a compressive force from the outer cylinder when the rotating shaft is stationary,
At the time of rotation of the rotating shaft, the stress applied to the permanent magnet was in a state where compressive force due to press-fitting of the outer cylinder and tensile stress due to centrifugal force were applied, and the rotation speed increased and the tensile stress exceeded the compressive stress and exceeded the permanent magnet tensile strength At this point, the permanent magnet will be cracked, so it is possible to increase the permanent magnet cracking rotation speed by the amount of preliminary compressive stress as compared to rotating the permanent magnet alone, and the outer cylinder Although it is subjected to stress due to press-fitting and also to stress due to centrifugal force during rotation, it is possible to respond to this by using a non-magnetic, high-tension material with a high linear expansion coefficient for the outer cylinder. The permanent magnet outer cylinder has a seal-fitting structure in which the outer periphery of both ends of the opening of the permanent magnet is pressed by the side plate. Department By welding, bonding, or press-fitting the soldering fitting, the permanent magnet outer cylinder and the side plate can be made into a state close to an integral structure. By making it shorter, the side plate can suppress the movement of the permanent magnet in the axial direction,
As a result, the bending rigidity of the permanent magnet rotor can be improved, and the reliability of the shaft system can be improved as a permanent magnet rotor of an ultra-high-speed rotating machine such as a turbocharger direct-coupled rotating machine.

Embodiment An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a sectional view showing an embodiment of a permanent magnet rotor of an ultrahigh-speed rotating machine according to the present invention. In FIG. 1, the present permanent magnet rotor comprises a cylindrical permanent magnet 3, an outer cylinder 1 provided on the outer periphery of the permanent magnet 3, and side plates 2a, 2b provided on the side surfaces of the permanent magnet 3. Press the magnet into the outer cylinder,
In addition, the outer periphery of the opening at both ends of the outer cylinder is formed by fitting the inner periphery of the side plates 2a and 2b.

The cylindrical permanent magnet 3 is made of, for example, Sm-Co or Nd-Fe-
It uses a high magnetic force of the permanent magnet of the B system, 7~8kg / mm ² approximately in considerably weaker Sm-Co based permanent magnet tensile strength compared to these permanent magnets general steel, Nd-Fe-B based permanent Since the magnet has only about 15 to 20 kg / mm ² , it is used as a rotor 8a of an ultra high-speed rotating machine 8 incorporated between a collar 10 and a bearing 10a on a rotating shaft 6a of a turbocharger as shown in FIG. In this case, the permanent magnet 3 alone will be damaged, and in the structure of the related art provided with an outer cylinder for preventing the scattering of the permanent magnet, the permanent magnet will be built inside the outer cylinder when an excessive centrifugal force is applied. In the present invention, the permanent magnet 3 is detached because the rotor is unbalanced and the balance of the rotor is disturbed and the balance of the entire shaft system is disturbed and eventually the shaft is broken. The temperature difference is press-fitted into the cylinder 1 and the side plates 2a, The inner periphery of 2b has a structure in which the inner periphery of the permanent magnet 3 is fitted to prevent the occurrence of cracking of the permanent magnet 3 inside the outer cylinder 1 and the bending rigidity of the permanent magnet rotor 8a is improved.

FIG. 2 is an explanatory view exemplifying a rotation speed-stress curve of the permanent magnet 3 and the outer cylinder 1 of the rotor of FIG. 1, and FIG. 3 exemplifies a rotor stress state when the rotor is stationary in FIG. FIG. In FIG. 2, the horizontal axis indicates the rotor rotation speed, and the vertical axis indicates the tensile / compression stress, and the stress curves plotting the stress applied to the permanent magnet 3 and the outer cylinder 1 at each rotation speed are shown. FIG. 3 also shows a stress curve of the permanent magnet 3 alone. However, since the permanent magnet 3 is press-fitted into the outer cylinder 1, the permanent magnet 3 initially receives a compressive stress due to press-in as shown in FIG. Is initially subjected to a tensile stress due to press-in, and as the rotational speed increases, the tensile stress due to the centrifugal force of the outer cylinder 1 and the permanent magnet 3 increases. The compression force due to the press-fitting cancels the tensile stress caused by the press-fitting, and the rotation speed at which the cracks of the permanent magnet 3 corresponding to the tensile strength of the permanent magnet 3 occur can be increased as compared with the case where the permanent magnet is rotated alone.

In order to press-fit the permanent magnet 3 into the outer cylinder 1, the outer cylinder 1
In this case, the permanent magnet 3 is press-fitted without expanding the outer cylinder 1, and the permanent magnet 3 is press-fitted without expanding the outer cylinder 1.
Since the material is very brittle, chipping occurs at the time of press-fitting, and sufficient press-fit cannot be obtained. In addition, the initial press-fit dimension must be such that the initial press-fit does not exceed the tensile strength of the outer cylinder 1 and that the press-fit does not disappear at the operating temperature. It is determined so that the permanent magnet 3 and the outer cylinder do not break when received.

The material of the outer cylinder 1 must be non-magnetic because it is provided on the outer periphery of the permanent magnet 3, but it is necessary to use a material having a high linear expansion coefficient for press-fitting by heating. system heat-resistant steel and N _i based alloys such as well, these materials are high tensile at a by the linear expansion coefficient is high upon tolerable temperature is high, the linear expansion coefficient at temperature capacity is 0.0125 and N _i groups of austenitic heat-resistant steels 0.0091 with alloy
However, if the expansion rate at this service temperature is 0.007
If the temperature falls below the level, sufficient thermal expansion cannot be obtained, so that it can be said that it is not suitable for the heating press-fitting method.

FIG. 4 shows a permanent magnet 3 in assembling the rotor of FIG.
It is explanatory drawing which illustrates the press-fitting method to the outer cylinder 1 of FIG. In FIG. 4, the outer cylinder 1 as described above is assembled to the press-fitting employment 4,
The assembling portion receives the stamping fitting portion on the outer periphery of the opening at one end surface of the outer cylinder 1 by press-fitting 4. Next, the whole of the press-fit 4 is put into a heating furnace and heated. The heating temperature must not exceed the material service temperature of the outer cylinder 1, and the limit of the heating temperature is about 800 ° C. in consideration of assemblability and production equipment. Will be about. The heated outer cylinder 1 is taken out of the heating furnace together with the press-fit 4 and dropped into the permanent magnet guide pin at the center of the press-fit 4 with the inner diameter of the permanent magnet 3. This eliminates the problem that the permanent magnet 3 stops during insertion into the outer cylinder 1, and the press-fitting operation due to the temperature difference between the outer cylinder 1 and the permanent magnet 3 can be performed satisfactorily.

Next, a method of joining the outer cylinder 1 of the rotor and the soldering fitting portions of the side plates 2a and 2b in FIG. 1 is such that a step is provided on the outer peripheral portion of the side plates 2a and 2b. When the outer cylinder 1 is assembled to the stepped outer periphery of both ends of the outer cylinder 1, the outer cylinder 1 has a structure that can be suppressed from the outer periphery of the both ends of the outer cylinder 1.
a, 2b are formed so as to close the openings at both ends of the outer cylinder 1.
It is preferable that the outer cylinder 1 has a cylindrical structure in order to press-fit the permanent magnet 1 with a temperature difference as described above. However, if the outer cylinder 1 is formed in a U-shape, thermal expansion of the outer cylinder inlet and the bottom is required. A difference is generated, and the permanent magnet 3 cannot be inserted to the bottom.
The joining strength of the soldering fitting portions on the outer periphery of the opening at both ends of the outer cylinder 1 can be increased by using a method such as welding, adhesion, or press-fitting. In this way, the force that tends to spread to the outside of the outer cylinder 1 can be suppressed by the side plates 2a and 2b, and since the outer peripheral member of the permanent magnet 3 has a structure that is almost integral, the bending rigidity of the entire rotor is reduced. improves.

5 (a), 5 (b) and 5 (c) are partial sectional views showing another embodiment of the permanent magnet rotor of the ultrahigh-speed rotating machine according to the present invention. 5 (a), 5 (b) and 5 (c) show modified examples of the stamping fitting structure of the outer cylinder 1 and the side plates 2a and 2b of the rotor shown in FIG. 1, respectively. a) is a cylindrical shape having no step on the outer periphery of the opening at both end surfaces of the outer cylinder 1,
FIGS. 5B and 5C show a structure in which the outer diameters of the openings at both end surfaces are suppressed by the outer peripheral step portions of the side plates 2a and 2b. 2b are provided on the periphery of each other.
The structure is suppressed by b. Also in the case of these stamping fitting parts, the joining strength of the stamping fitting part can be increased by a method such as welding, adhesion or press fitting. Also permanent magnet 3
The outer peripheral member has a structure that is almost integral, so that the bending rigidity of the entire rotor is improved.

FIG. 6 is an enlarged cross-sectional view of a stamping fitting portion of the permanent magnet rotor of the ultrahigh-speed rotating machine according to the present invention. FIG. 6 shows an assembled state of the permanent magnet 3, the outer cylinder, and the side plate of the rotor shown in FIG. 1. By making the axial length of the outer cylinder 1 shorter than the axial length of the permanent magnet 3, The soldering fitting portion between the outer cylinder 1 and the side plates 2a, 2b is joined only on the surface in the circumferential direction, and the joint with the permanent magnet 3 is a structure consisting only on the side surfaces of the side plates 2a, 2b. The magnet 3 does not shift or move inside the outer cylinder 1 and the side plates 2a and 2b. Further, it is possible to provide a structure that does not cause axial distortion of the rotor when the rotor is attached to an ultrahigh-speed rotating machine.

When the rotor of the above embodiment is assembled as the permanent magnet rotor 8a of the turbocharger of FIG. 7, the rotor 8a
Is fitted to the rotating shaft 6a by about 3 to 5 μm,
Nut via collar 9 and compressor impeller 7
12 is tightened, where the rotor
The fitting portion of the rotating shaft 6a of the permanent magnet rotor 8a is only the inner diameter portion of the side plates 2a and 2b.Therefore, the invariance of the axial dimension of the permanent magnet rotor 8a is also an important point. It turns out that the child can respond to this.

[Effects of the Invention] According to the present invention, the permanent magnet of the permanent magnet rotor of the ultrahigh-speed rotating machine is pressed into the outer cylinder by a temperature difference or the like, and the inner periphery of the side plate is marked on the outer periphery of the opening at both ends of the outer cylinder. Since it is configured to be brazed, it is possible to increase the rotation speed of magnet crack generation, for example, when using a permanent magnet with an outer diameter of about 20 mm, the permanent magnet alone cracked at about 80000 γ / min Can be increased up to about 130,000 γ / min, and depending on the material of the outer cylinder, the rotation speed at which cracks occur can be further increased, and the force applied to the outer cylinder in the outer circumferential direction is applied to the outer cylinder. This can be suppressed by the side plates at both ends, and there is an effect that the bending rigidity of the rotor can be improved.

In addition, by making the permanent magnet shaft length longer than the outer cylinder shaft length, unnecessary gaps between components during rotor assembly can be eliminated, preventing distortion during assembly into the rotating machine body, and reducing the rotor itself. Bending stiffness can be improved, and by welding, bonding or press-fitting the soldering joint between the outer cylinder and the side plate, the joining force is further increased, and the rotor is made closer to an integral structure to increase the bending stiffness. These effects reduce the unbalance of the rotor over time and improve the bending rigidity of the rotor itself.If this is used for a turbocharger direct-coupled rotating machine, etc., the rigidity of the entire shaft diameter is improved. Therefore, there is an effect that the reliability can be expected to be improved by increasing the shaft breaking rotation speed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a permanent magnet rotor of an ultrahigh-speed rotating machine according to the present invention, FIG. 2 is an explanatory view of a rotation speed-stress curve of the permanent magnet and the outer cylinder of FIG. FIG. 4 is an explanatory view of an example of the assembly press-fitting method of FIG. 1, and FIG.
(B) and (c) are partial sectional views showing another embodiment according to the present invention, FIG. 6 is a partial sectional view showing still another embodiment according to the present invention, and FIG. 7 is a conventional turbocharger direct-coupled rotating machine. FIG. 3 is a cross-sectional view showing one example. 1 ... outer cylinder, 2a, 2b ... side plate, 3 ... permanent magnet, 6a ...
… Rotary shaft, 8a …… rotor.

Continuation of the front page (56) References JP-A-3-11950 (JP, A) JP-A-3-11948 (JP, A) JP-A-2-241339 (JP, A) JP-A-2-123939 (JP) , A) JP-A-62-254649 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02K 1/27 501

Claims (3)

(57) [Claims] 1. A permanent magnet rotor comprising a cylindrical permanent magnet, an outer cylinder that covers the outer periphery of the permanent magnet, and a side plate that covers the side surface of the permanent magnet, wherein the total length of the outer cylinder is greater than the total length of the permanent magnet. The permanent magnet is press-fitted into the outer cylinder, and the outer peripheries of the openings at both end surfaces of the outer cylinder are stamped and fitted with the inner perimeter of the side plate. A permanent magnet rotor for an ultra-high-speed rotating machine. 2. The permanent magnet rotor according to claim 1, wherein the outer cylinder is made of heat-resistant austenitic steel or a Ni-based alloy. 3. The permanent magnet rotor for an ultra-high speed rotating machine according to claim 1, wherein said soldering fitting portion is welded, bonded or press-fitted.