JP4837288B2 - Rotor - Google Patents

Description

  The present invention relates to a permanent magnet type rotor in which a permanent magnet is disposed on a rotor.

2. Description of the Related Art Conventionally, a permanent magnet type IPM (Interior Permanent Magnet) rotor in which a magnet is disposed inside a rotor yoke is known.
As this type of rotor, there is a rotor provided with a magnet removal prevention plate for restricting the movement of the magnet in the axial direction.

For example, Non-Patent Document 1 discloses a technique for manufacturing a rotor magnet removal prevention plate with a sintered material. In this magnet slip-off preventing plate, the leakage of magnetic flux is prevented by using a bronze-based sintered material (non-magnetic material) at the contact portion with the magnet. On the other hand, an iron-based sintered material (magnetic material) that is advantageous in terms of cost is used for the base portion.
TOYOTA Technical Review Vol.52 No.2 Dec.2002

  However, if the magnet slip prevention plate is manufactured by sintering as in the prior art, a press molding machine corresponding to the rotor diameter is required, so it is difficult to manufacture the magnet slip prevention plate used for a rotor with a large diameter. There is a problem that. Therefore, the size of the rotor diameter in which the magnet removal preventing plate is used is also limited, and there is a problem that a high drive current is required when a large torque is required.

  Further, since warping and waviness due to thermal stress distortion occur during sintering and heat treatment, thin-wall molding is difficult. Therefore, when using a magnet slip prevention plate without machining and only sintering, there is a problem that the thickness must be increased and the weight increases. On the other hand, it is conceivable to produce a thin-walled product by machining after sintering, but there is a problem that the production process is increased and the production efficiency is lowered.

  Accordingly, an object of the present invention is to provide a rotor capable of increasing the rotor diameter and reducing the weight while preventing leakage of magnetic flux.

The invention according to claim 1 is a shaft (for example, the rotor shaft 3 in the embodiment) disposed along the axis, and a yoke (for example, the rotor yoke 4 in the embodiment) fixed to the outer peripheral side of the shaft. ), A permanent magnet disposed in the yoke (for example, the permanent magnet 6 in the embodiment), and an axial end of the permanent magnet are disposed adjacent to each other to move the permanent magnet in the axial direction. End plate to be regulated (for example, end plates 7 and 7 in the embodiment) and a fixing member having an annular inner peripheral surface that is press-fitted into the cylindrical outer peripheral surface of the shaft to fix the end surface plate ( for example, a color 8) in the embodiment, the fixing member is formed, Ri Do from those linear expansion coefficient and substantially the same said shaft, said end sheet is the larger non-magnetic material linear expansion coefficient than that of the shaft the is that is And butterflies.

  According to this invention, since the said end surface board and the said fixing member can be manufactured separately, the thing of the material suitable for each member can be used. Therefore, since the end face plate and the fixing member can be manufactured without performing a sintering process, the diameter of the end face plate and the yoke using the end face plate can be increased. In addition, since the thickness of the end face plate and the fixing member can be reduced while maintaining the required accuracy, the weight can be reduced.

Further, by making the fixing member substantially the same as the linear expansion coefficient of the shaft, the fixing member can be attached to the shaft even when the end face plate having a linear expansion coefficient larger than that of the shaft is used. The end face plate can be fixed by press-fitting into.
Here, it is preferable to use a nonmagnetic material (SUS304, Al, Cu) for the end face plate in terms of preventing magnetic flux leakage of the permanent magnet. Moreover, it is preferable to use a ferrous material for the fixing member and the shaft.

The invention according to claim 2 is the invention according to claim 1, wherein the fixing member is manufactured by cutting a seamless steel pipe (for example, the seamless steel pipe 16 in the embodiment). .
According to this invention, a plurality of the fixing members can be continuously manufactured by sequentially performing the cutting process in a state in which one end face side of the seamless steel pipe is chucked, thereby improving the production efficiency. it can. In addition, when the fixing member is press-fitted on the outer peripheral side of the shaft, the fixing member is formed in a substantially annular shape, so that the yield is significantly improved as compared with the case where a plate-like member is press-molded. Can do. In addition, a stable strength can be ensured by cutting the seamless member by cutting a seamless steel pipe without a weld seam.
Here, the end face plate is preferably press-molded. By press-fitting and fixing the end face plate with the fixing member, the end face plate can be made thinner and lighter.

The invention according to claim 3 is characterized in that both sides of the inner peripheral portion of the fixing member are chamfered .

According to the present invention, since the fixing member can be assembled from either direction, the assemblability is improved.

According to a fourth aspect of the present invention, there is provided a shaft disposed along the axis, a yoke fixed to the outer peripheral side of the shaft, a permanent magnet disposed on the yoke, and movement of the permanent magnet in the axial direction. In the rotor including an end face plate to be regulated, at least one of the pair of end face plates arranged on both sides of the permanent magnet (for example, the end face plate 9 in the embodiment) is substantially the same as the shaft. It is formed by a nonmagnetic material having a linear expansion coefficient of.

  According to this invention, magnetic flux leakage of the permanent magnet from the end face plate can be prevented by forming the at least one end face plate from the nonmagnetic material. The permanent magnet can be held by the pair of end face plates. Moreover, since the at least one end face plate has a linear expansion coefficient substantially the same as that of the shaft, the fixed state of the at least one end face plate and the shaft can be maintained without depending on a temperature change. The movement of the permanent magnet in the axial direction can be reliably restricted by the at least one end face plate.

The fifth invention is characterized in that the at least one end face plate is formed of a material containing a predetermined amount of nickel and chromium in an iron-based alloy.
According to this invention, the iron-based alloy, which is a nonmagnetic material, is formed of a material containing a predetermined amount of nickel and chromium, thereby improving the strength while maintaining the at least one end face plate nonmagnetic. can do.

The sixth invention is characterized in that the at least one end face plate contains 20 to 30% by weight of nickel and 15 to 30% by weight of chromium.
According to the present invention, it is possible to ensure a necessary and sufficient strength for restricting the movement of the permanent magnet in the axial direction while keeping the at least one end face plate nonmagnetic.

The seventh invention is characterized in that the at least one end face plate further contains 0.5 to 5% by weight of aluminum.
According to this invention, by further containing 0.5 to 5% by weight of aluminum, the electrical resistance of the at least one end face plate can be increased, and eddy currents generated in the rotor can be suppressed. The efficiency of the rotor can be improved. Furthermore, corrosion resistance can be improved.

The eighth invention is characterized in that the at least one end face plate is manufactured by a powder metallurgy manufacturing method.
According to the present invention, the at least one end face plate can be manufactured with high accuracy according to strength and design requirements by making use of the characteristics of the powder metallurgy manufacturing method.

The ninth invention is characterized in that the at least one end face plate has a convex portion protruding in the axial direction on the inner peripheral side, and is fixed to the shaft by caulking the convex portion.
According to this invention, since the at least one end face plate is fixed to the shaft by caulking the convex portion, there is no need to separately provide a fixing member, and the number of parts can be reduced and further weight reduction can be achieved. Is possible.

  According to the invention which concerns on Claim 1, since the diameter of the said end surface plate and the yoke using this can be increased, while being able to enlarge a rotor, it becomes possible to achieve weight reduction. Moreover, even when a nonmagnetic material having a large linear expansion coefficient is used for the end face plate, the end face plate can be fixed by the fixing member.

According to the invention according to claim 2, in addition to the effect of the invention according to claim 1, the production efficiency can be increased, the yield can be greatly improved, and a stable strength can be secured.
According to the invention which concerns on Claim 3, since a fixing member can be assembled | attached from which direction, an assembly property improves.

According to the fourth invention, the at least one end face plate can prevent leakage of magnetic flux of the permanent magnet from the end face plate, and the permanent magnet can be held by the pair of end face plates. Further, the movement of the permanent magnet in the axial direction can be reliably restricted by the at least one end face plate.

According to the fifth invention, the strength can be improved while maintaining the at least one end face plate nonmagnetic.
According to the sixth aspect of the invention, it is possible to secure a necessary and sufficient strength for restricting the movement of the permanent magnet in the axial direction while keeping the at least one end face plate nonmagnetic.

According to the seventh aspect, the electrical resistance of the at least one end face plate can be increased and the eddy current generated in the rotor can be suppressed, so that the efficiency of the rotor can be improved. Furthermore, corrosion resistance can be improved.
According to the eighth aspect of the invention, it can be manufactured with high accuracy in accordance with strength and design requirements.
According to the ninth aspect , the number of parts can be reduced and further weight reduction can be achieved.

Hereinafter, a rotor according to an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, a rotor provided in a motor used with an engine as a drive source of a hybrid vehicle will be described.
FIG. 1 is an exploded perspective view of a permanent magnet type rotor 1 according to a first embodiment of the present invention. As shown in the figure, the rotor 1 includes a substantially cylindrical rotor shaft 3, a rotor yoke (laminated core) 4 provided on the outer peripheral side, a plurality of permanent magnets 6, a pair of end face plates 7, 7, Color 8 is provided.

The rotor shaft 3 has a hollow drum shape and is integrally formed by casting or forging. The rotor shaft 3 includes a main body 3a formed in a substantially cylindrical shape with an outer diameter, and a diameter-enlarged portion 3b that is larger in diameter than the main body 3a on the base end side of the main body 3a (see FIG. 2). ).
In the present embodiment, the rotor shaft 3 is connected to a crankshaft (not shown) of the engine so that the torque of the engine or motor can be transmitted.

  The rotor yoke 4 is configured by laminating a plurality of electromagnetic steel plates 5 ... 5 in the axial direction. Each of the electromagnetic steel plates 5 ... 5 has a substantially annular shape in which a hole is formed, and the magnets of the rotor yoke 4 are laminated by aligning the respective holes of the electromagnetic steel plates 5 ... 5. An insertion hole 10 is formed.

Permanent magnets 6 having a substantially rectangular cross section are arranged in the magnet insertion holes 10 of the rotor yoke 4, and a magnetic flux is generated by each permanent magnet 6.
In the present embodiment, a substantially pair of end face plates 7 and 7 are attached to both end faces of the rotor yoke 4 in which the magnet 6 is inserted. The end surface plates 7 and 7 are formed in a substantially annular shape, and are made of a nonmagnetic material such as austenitic stainless steel SUS.
In the present embodiment, an annular collar 8 having a diameter substantially equal to that of the rotor shaft main body 3a is provided. The collar 8 is for fixing the end face plates 7 and 7.

FIG. 2 is a cross-sectional view of the rotor 1 in a state where the members shown in FIG. 1 are assembled. As shown in the figure, on the outer peripheral side of the main body portion 3 a of the rotor shaft 3, a rotor yoke 4 into which the permanent magnet 6 is inserted and end face plates 7 and 7 disposed on both ends of the rotor yoke 4 are disposed. . At this time, one end face plate 7 facing the enlarged diameter portion 3b is in close contact with the enlarged diameter portion 3b of the rotor shaft 3. A collar 8 is press-fitted at the distal end side of the main body 3 a of the rotor shaft 3 so as to be in close contact with the other end face plate 7. The end plate 7 is fixed by the collar 8.
The rotor shaft 3 is connected to an engine crankshaft (not shown).

  By comprising in this way, since end face plates 7 and 7 can regulate the movement of the magnet 6 in the axial direction, the magnet 6 can be stably held at a predetermined position, Reliability is improved. Further, the end plates 7 and 7 can protect the magnet 6 from the outside.

In the present embodiment, the end face plates 7 and 7 and the collar 8 can be individually manufactured, so that materials suitable for the members 7 and 8 can be used. Therefore, since the end face plates 7 and 7 and the collar 8 can be manufactured without performing a sintering process, the diameter of the end face plates 7 and 7 and the yoke 4 using the end face plates 7 and 7 can be increased. In addition, since the thickness of the end face plates 7 and 7 and the collar 8 can be reduced while maintaining the required accuracy, the weight can be reduced.
Here, the end face plates 7 are preferably press-molded. By press-fitting and fixing the end face plates 7 and 7 with the collar 8, the end face plates 7 and 7 can be made thinner and lighter.

  Moreover, when mounted on a vehicle, the weight of the motor can be reduced, so that the inertia can be lowered. Therefore, responsiveness and response when the accelerator is depressed can be improved, and fuel consumption can be improved.

  The collar 8 is manufactured by cutting a seamless steel pipe 16 (see FIG. 4). FIG. 4 is a perspective view of a seamless steel pipe 16 which is a base material of the collar 8 shown in FIG. As shown in the figure, the seamless steel pipe 16 having no weld seam is formed in a cylindrical shape having both end faces opened. A collar 8 as shown in FIG. 5 can be manufactured by chucking one end of the seamless steel pipe 16 and cutting it with a cutter to a predetermined thickness.

In this way, by sequentially cutting the seamless steel pipe 16, a plurality of the collars 8 can be manufactured continuously, so that the production efficiency can be increased.
Further, when the collar 8 is press-fitted into the outer peripheral side of the shaft 3, since the collar 8 is formed in a substantially annular shape, the yield is greatly improved compared to the case where a flat plate member is press-molded. be able to. In addition, by manufacturing the collar 8 by cutting the seamless steel pipe 16 without a weld seam, it is possible to select a hard material that is difficult to punch by press molding, and to secure a stable strength.

  In the present embodiment, as shown in FIG. 3, the chamfered portions 12 and 12 are formed by chamfering both sides of the inner peripheral portion of the collar 8. In this way, by chamfering both sides of the inner peripheral portion of the collar 8, the collar 8 can be assembled from either direction, so that the assemblability is improved.

  In addition, by making the collar 8 substantially the same as the linear expansion coefficient of the shaft 3, even if the end face plates 7 and 7 have a linear expansion coefficient larger than that of the shaft 3, The end face plate can be fixed by press-fitting the collar 8 into the shaft 3. This will be described with reference to FIG.

  FIG. 6 is a graph showing the coefficient of thermal expansion at each temperature for the rotor shaft and collar material shown in FIG. As shown in the figure, as materials, (i) carbon steel, carbon molybdenum steel, low chromium steel, (ii) alloy steel with 5-9% chromium content, (iii) austenitic stainless steel (18Cr8Ni), (Iv) Austenitic stainless steel (25Cr20Ni) and (v) aluminum. Among these, materials that can be used for the shaft and collar are those shown in (i) and (ii) in terms of strength. Moreover, as a material which can be used for an end surface board, it will be shown to (iii)-(v) which is a nonmagnetic material.

When the material of the rotor shaft 3 and the collar 8 is selected, the ratio of the linear expansion coefficient between the collar 8 and the shaft 3 is in a temperature range of 20 to 200 ° C.
Formula (1): (Linear expansion coefficient of collar 8) / (Linear expansion coefficient of shaft 3) ≦ 1.1
It is preferable that the relationship is satisfied. In the case of the above materials, if the material of (i) is used for the material of the collar 8 and the material of (ii) is used for the material of the shaft 3, the ratio of the linear expansion coefficient between the collar 8 and the shaft 3 is 1.07. This is preferable. In addition, when satisfy | filling the intensity | strength conditions, it is more preferable to use the same thing for the material of the rotor shaft 3 and the collar | collar 8. FIG.

  Thus, the collar 8 is a case where a nonmagnetic material having a large linear expansion coefficient is used for the end face plates 7 and 7 by selecting a material substantially the same as the linear expansion coefficient of the shaft 3 as a material. Also, the end face plates 7 can be fixed by the collar 8. Further, since the press-fit allowance can be set without considering the thermal expansion difference due to heat generation at the time of high rotation, the degree of freedom in design increases.

Next, a second embodiment of the present invention will be described with reference to FIG. In the figure, the same members as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted as appropriate.
In the present embodiment, one end face plate 9 of the pair disposed on both sides with the permanent magnet 6 interposed therebetween is provided with a convex portion 13 projecting in the axial direction on its inner peripheral side, and the convex portion The point which is fixed to the shaft 3 by caulking 13 is different from the first embodiment. As described above, the one end face plate 9 is fixed to the shaft 3 by caulking the convex portion 13, so that the nonmagnetic function required for the end face plate 7 and the fixing member (collar) 8 are required. The function of making the shaft tightening allowance constant within the operating temperature can be realized. Furthermore, it is not necessary to separately provide a fixing member (collar 8) as in the first embodiment, so that the number of parts can be reduced and further weight reduction can be achieved.

  Then, by forming the one end face plate 9 with a non-magnetic material having substantially the same linear expansion coefficient as that of the shaft 3, the magnetic flux leakage of the permanent magnet 6 from the end face plate 9 can be prevented. In addition, by setting the one end face plate 9 to substantially the same linear expansion coefficient as that of the shaft 3, it is possible to maintain the fixed state between the at least one end face plate 9 and the shaft 3 without depending on a temperature change. Therefore, the movement of the permanent magnet 6 in the axial direction can be reliably restricted by the one end face plate 9. Here, it is preferable that the one end face plate 9 has a ratio to the linear expansion coefficient of the shaft 3 in the range of 0.9 to 1.1.

  In addition, the one end face plate 9 contains a predetermined amount of nickel and chromium in a ferrous alloy and an aluminum alloy (for example, materials shown in FIGS. 6 (iii) to (v)) which are nonmagnetic materials. By forming it with a material, the strength can be improved while maintaining the one end face plate 9 non-magnetic. Further, the linear expansion coefficient can be kept constant. In particular, when 20 to 30% by weight of nickel and 15 to 30% by weight of chromium are contained, the permanent magnet 6 is moved in the axial direction while maintaining the one end face plate 9 nonmagnetic. It is possible to ensure the necessary and sufficient strength to regulate the above.

  The one end face plate 9 further contains 0.5 to 5% by weight of aluminum, so that the electric resistance of the one end face plate 9 can be increased, and the eddy current generated in the rotor 1 is suppressed. Therefore, the efficiency of the rotor 1 can be improved. Furthermore, corrosion resistance can be improved. Furthermore, the one end face plate 9 can be manufactured with high accuracy according to strength and design requirements by making use of the characteristics of the powder metallurgy manufacturing method.

  Of course, the contents of the present invention are not limited to the above-described embodiments. For example, in the embodiment, the motor rotor mounted on the vehicle has been described, but the application target is not limited thereto. In the first embodiment, the configuration in which the collar is provided on one end face plate of the rotor yoke has been described, but the collar may be provided on both end face plates. Moreover, in 2nd Embodiment, although the structure provided with a convex part in one end surface plate was demonstrated, you may make it provide a convex part in both end surface plates, respectively. Moreover, although the case where it applied to an IPM rotor was demonstrated in embodiment, you may apply to the SPM rotor which arrange | positions a magnet on the surface of a rotor yoke.

It is a disassembled perspective view of the rotor in the 1st Embodiment of this invention. It is sectional drawing of a rotor in the state which assembled | attached each member shown in FIG. FIG. 2 is a partial cross-sectional view of the collar shown in FIG. 1. It is a perspective view of the seamless steel pipe used as the base material of the color shown in FIG. It is a perspective view of the color manufactured from the seamless steel pipe shown in FIG. It is a graph which shows the thermal expansion coefficient for every temperature about the material of a rotor shaft and a collar shown in FIG. It is principal part sectional drawing of the rotor in the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rotor 3 ... Rotor shaft 4 ... Rotor yoke 6 ... Permanent magnet 7 ... End face plate 8 ... Collar (fixing member)
16 ... Seamless steel pipe

Claims (3)

A shaft disposed along the axis;
A yoke fixed to the outer peripheral side of the shaft;
A permanent magnet disposed on the yoke;
An end face plate disposed adjacent to the axial end of the permanent magnet and restricting movement of the permanent magnet in the axial direction;
A fixing member having an annular inner peripheral surface that is press-fitted into the cylindrical outer peripheral surface of the shaft and fixes the end face plate;
The fixing member is Ri Do from those linear expansion coefficient and having substantially the same of the shaft,
The rotor, wherein the end face plate is formed of a nonmagnetic material having a larger linear expansion coefficient than the shaft .   The rotor according to claim 1, wherein the fixing member is manufactured by cutting a seamless steel pipe. The rotor according to claim 1, wherein both sides of the inner peripheral portion of the fixing member are chamfered.

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