Patent ID: 12249872

DESCRIPTION OF THE EMBODIMENTS

The first layer, the second layer, and the third layer of the sleeve are integrated side by side in this order from the radial center of the sleeve toward the outside. When the rotor shaft is inserted into the sleeve, the amount of deformation of the sleeve in the direction in which the inner diameter of the sleeve is increased (hereinafter also referred to as the diameter increasing direction) increases as it is closer to the radial center of the sleeve. That is, the amount of deformation of the sleeve in the diameter increasing direction is the largest in the first layer and the smallest in the third layer.

The first fiber-reinforced resin of the first layer includes the first carbon fiber extending in a direction inclined with respect to both the axis of the rotor shaft and the circumferential direction of the sleeve. Therefore, in the first layer, for example, the carbon fiber is more easily elastically deformed in the diameter increasing direction than the fiber-reinforced resin layer (hoop winding layer) extending along the peripheral direction of the sleeve. Therefore, as described above, when the rotor shaft is inserted into the sleeve, it is possible to effectively prevent the first layer from breaking even if the amount of deformation of the first layer in the diameter increasing direction is large.

The second fiber-reinforced resin of the second layer includes the second carbon fiber extending along the circumferential direction of the sleeve. Therefore, the second layer has a larger elastic modulus (rigidity) in the diameter increasing direction than the first layer. Further, the third fiber-reinforced resin of the third layer includes the third carbon fiber extending along the circumferential direction of the sleeve. Further, the elastic modulus of the third layer is larger than the elastic modulus of the second layer. That is, in the sleeve, the elastic modulus becomes larger as the amount of deformation in the diameter increasing direction when the rotor shaft is inserted into the sleeve becomes smaller. Therefore, the second layer and the third layer are also prevented from breaking when the rotor shaft is inserted into the sleeve. Further, in the sleeve after being mounted on the rotor shaft, it becomes possible to satisfactorily hold the permanent magnet on the outer periphery of the rotor shaft since the second layer has a larger elastic modulus than that of the first layer, and the third layer has a larger elastic modulus than that of the second layer.

That is, according to the disclosure, it is possible to mount the sleeve on the rotor shaft while suppressing the breakage of the sleeve and to satisfactorily press the permanent magnet toward the rotor shaft by the elastic restoring force of the sleeve. As a result, the permanent magnet can be satisfactorily held on the outer periphery of the rotor shaft.

In the following figures, components having the same or similar functions and effects may be designated by the same reference numerals, and repeated description may be omitted.

As shown inFIG.1, a rotor10according to this embodiment configures a part of a rotary machine12. In addition to the rotor10, the rotary machine12includes a motor case14, a bearing16, and a stator18. The motor case14rotatably supports a rotor shaft22of the rotor10via a set of bearings16. As a result, the rotor shaft22can rotate around the axis. The set of bearings16are spaced apart from each other in the axial direction of the rotor shaft22. Hereinafter, the direction along the axis of the rotor shaft22is also referred to as the axial direction of the rotor shaft22.

The rotor shaft22has a main body part26and a pair of small diameter parts24. The pair of small diameter parts24are provided at both ends in a direction along the axis of the rotor shaft22(hereinafter, also referred to as an axial direction of the rotor shaft22). The main body part26has an outer diameter larger than that of the small diameter part24, and is provided between the small diameter parts24of the rotor shaft22(the center part in the axial direction of the rotor shaft22). Each of the pair of small diameter parts24of the rotor shaft22is supported by the bearing16. Further, the part of the rotor shaft22between the parts supported by the set of bearings16is housed inside the motor case14.

The stator18is housed inside the motor case14. The stator18has an electromagnetic coil28and a stator core (not shown). Inside the motor case14, the electromagnetic coil28and the stator core face each other at a distance from the outer periphery of the rotor10.

As shown inFIGS.1to3, the rotor10has a rotor shaft22, a permanent magnet30, and a sleeve32. The rotor shaft22has an outer periphery of a part (main body part26) facing the stator18. The permanent magnet30is attached to the outer periphery of the rotor shaft22. The sleeve32is disposed on the outer periphery of the permanent magnet30. The sleeve32presses the permanent magnet30toward the rotor shaft22. As a result, the sleeve32holds the permanent magnet30on the outer periphery of the rotor shaft22.

In this embodiment, the inner diameter of the sleeve32is smaller than the diameter of the part of the rotor shaft22including the permanent magnet30. Therefore, the sleeve32is disposed on the outer periphery of the permanent magnet30in a state of being elastically deformed in the direction of increasing the inner diameter of the sleeve32. That is, the permanent magnet30is pressed toward the rotor shaft22by the elastic restoring force of the sleeve32.

As shown inFIGS.2and3, the sleeve32has multiple annular ring members34. The ring members34are stacked on each other in the axial direction of the rotor shaft22. As a result, the sleeve32has a cylindrical shape as a whole. The cylindrical sleeve32is disposed coaxially with the rotor shaft22. As shown inFIG.3, each ring member34configuring the sleeve32has a first layer36, a second layer38, and a third layer40disposed concentrically in the axial direction of the sleeve32. The first layer36, the second layer38, and the third layer40are integrated side by side in this order from the radial center of the sleeve32toward the outside. Therefore, the second layer38is disposed outside the first layer36. The third layer40is disposed outside the second layer38.

The first layer36has a first fiber-reinforced resin. The first fiber-reinforced resin includes a first matrix resin and a first carbon fiber. Preferable examples of the first matrix resin include, but are not particularly limited to, epoxy resin, cyanate ester resin, vinyl ester resin, or a mixed resin in which at least two or more selected from these resins are mixed. The first carbon fiber extends in a direction inclined with respect to both the axis of the rotor shaft22(the axial direction of the sleeve32) and the circumferential direction of the sleeve32. That is, the first carbon fiber is so-called helically wound. The angle at which the extending direction of the first carbon fiber is inclined with respect to the axis of the rotor shaft22(hereinafter, also referred to as an inclination angle) is preferably 30° to 40° (the reason will be described later).

The second layer38has a second fiber-reinforced resin. The second fiber-reinforced resin includes a second matrix resin and a second carbon fiber. Preferable examples of the second matrix resin include, but are not particularly limited to, epoxy resin, cyanate ester resin, vinyl ester resin, or a mixed resin in which at least two or more selected from these resins are mixed. The second carbon fiber extends along the circumferential direction of the sleeve32. That is, the second carbon fiber is so-called hoop-wound.

The third layer40has a third fiber-reinforced resin. The third fiber-reinforced resin includes a third matrix resin and a third carbon fiber. Preferable examples of the third matrix resin include, but are not particularly limited to, epoxy resin, cyanate ester resin, vinyl ester resin, or a mixed resin in which at least two or more selected from these resins are mixed. The third carbon fiber extends along the circumferential direction of the sleeve32. That is, the third carbon fiber is so-called hoop-wound. Here, in the fiber-reinforced resin, the strength of the reinforced fiber in the extending direction is effectively enhanced. Therefore, each of the second layer38in which the second carbon fiber is hoop-wound and the third layer40in which the third carbon fiber is hoop-wound exhibit particularly high strength in the circumferential direction of the ring member34. That is, the second layer38and the third layer40show high strength in the direction of the centrifugal force applied to the permanent magnet30when the rotor10rotates.

The elastic modulus of the third layer40is larger than the elastic modulus of the second layer38. The elastic modulus of the second layer38is the tensile elastic modulus in the circumferential direction of the second layer38. The elastic modulus of the third layer40is the tensile elastic modulus in the circumferential direction of the third layer40. Further, it is preferable that the elongation rate in the circumferential direction of the third layer40is smaller than the elongation rate in the circumferential direction of the second layer38. The elastic modulus and elongation rate of the third layer40may be adjusted, for example, by selecting the type of the third carbon fiber. Further, the elastic modulus and the elongation rate of the second layer38may be adjusted, for example, by selecting the type of the second carbon fiber.

In each ring member34, it is preferable that when the thickness of the first layer36is 1, the total thickness of the thickness of the second layer38and the thickness of the third layer40is 7.9 to 28.7 (the reason will be described later). In this case, for example, the thickness of the first layer36is preferably 0.2 to 0.3 mm. Further, the total thickness of the second layer38and the third layer40is preferably 2.37 to 5.73 mm. The axial length of each ring member34is preferably 3.3 to 12.0 mm. A more preferable axial length of each ring member34is 6.0 to 8.0 mm.

The rotor10is basically configured as described above. Hereinafter, a method for manufacturing the rotor10according to this embodiment will be described with reference toFIGS.4to7. In the method for manufacturing the rotor10, first, a providing process is performed. In the providing process, the rotor shaft22(FIG.4) in which the permanent magnet30is disposed on the outer periphery and the sleeve32(ring member34inFIG.5) before being mounted on the rotor shaft22are provided. In this embodiment, the sleeve32provided in the providing process is multiple ring members34before being mounted on the rotor shaft22.

Next, the jig mounting process is performed. As shown inFIGS.4and5, in the jig mounting process, a mounting jig42is mounted at one end of the rotor shaft22in the extending direction. In this embodiment, the mounting jig42is provided with an insertion hole44along the axial direction of the mounting jig42. The mounting jig42is attached to the rotor shaft22by inserting one of the small diameter parts24of the rotor shaft22into the insertion hole44.

The mounting jig42has a small diameter part46, a large diameter part48, and a tapered part50. The outer diameter of the small diameter part46is equal to or less than the inner diameter of the sleeve32(each ring member34) before being mounted on the rotor shaft22. The outer diameter of the large diameter part48is the same as the outer diameter of the part of the rotor shaft22including the permanent magnet30. The “same diameter” here includes the case where the outer diameter of the large diameter part48and the outer diameter of the part of the rotor shaft22including the permanent magnet30are substantially the same.

The tapered part50is tapered from the large diameter part48toward the small diameter part46. When the mounting jig42is mounted on the rotor shaft22, the large diameter part48of the mounting jig42is disposed so as to be continuously adjacent to the part of the rotor shaft22including the permanent magnet30. That is, the small diameter part46of the mounting jig42is disposed closer to one end of the rotor shaft22than the large diameter part48.

Next, the mounting process is performed. In the mounting process, as shown inFIGS.6and7, the sleeve32is mounted on the outer periphery of the permanent magnet30of the rotor shaft22. In this embodiment, the rotor shaft22is inserted inside the ring members34via the mounting jig42attached to the rotor shaft22.

Specifically, the mounting jig42is inserted into the ring member34from the small diameter part46thereof. Then, the ring member34is relatively moved toward the large diameter part48while sliding the inner peripheral surface of the first layer36of the ring member34and the outer peripheral surface of the tapered part50. As a result, the inner diameter of the ring member34is increased according to the outer diameter of the tapered part50. When the ring member34reaches the large diameter part48, the inner diameter of the ring member34is increased until it reaches the outer diameter of the part of the rotor shaft22including the permanent magnet30. Therefore, the part of the rotor shaft22including the permanent magnet30can be easily inserted inside the ring member34elastically deformed in the direction of increasing the inner diameter of the ring member34(hereinafter also referred to as the diameter increasing direction).

In the mounting process, the ring member34is disposed at one end in the axial direction of the part of the rotor shaft22including the permanent magnet30via the mounting jig42as described above. The ring member34is relatively moved toward the other end in the axial direction of the part of the rotor shaft22including the permanent magnet30. At this time, the first layer36and the outer peripheral surface of the permanent magnet30are slid along the axial direction of the ring member34along the axial direction of the rotor shaft22. When the ring member34is relatively moved with respect to the mounting jig42and the rotor shaft22, for example, a press mechanism (not shown) may be used. The press mechanism abuts on the axial end surface of the ring member34and can press the ring member34along the axial direction.

By stacking the ring members34in the axial direction of the rotor shaft22as described above, a cylindrical sleeve32may be formed on the outer periphery of the permanent magnet30of the rotor shaft22. As a result, the rotor10(FIG.2) in which the permanent magnet30is held on the outer periphery of the rotor shaft22is obtained in a state where the permanent magnet30is pressed toward the rotor shaft22by the elastic restoring force of the sleeve32.

From the above, in the method for manufacturing the rotor10according to this embodiment, the rotor10is obtained by inserting the rotor shaft22into the ring member34(sleeve32). At this time, the amount of deformation of the ring member34in the diameter increasing direction increases as it is closer to the radial center of the sleeve32. That is, the amount of deformation of the ring member34in the diameter increasing direction is the largest in the first layer36and the smallest in the third layer40.

The first fiber-reinforced resin of the first layer36includes the first carbon fiber extending in a direction inclined with respect to both the axis of the rotor shaft22and the circumferential direction of the ring member34. Therefore, in the first layer36, for example, the carbon fiber is more easily elastically deformed in the diameter increasing direction than the fiber-reinforced resin layer (hoop winding layer) extending along the peripheral direction of the ring member34. Therefore, as described above, when the rotor shaft22is inserted into the ring member34, it is possible to effectively prevent the first layer36from breaking even if the amount of deformation of the first layer36in the diameter increasing direction is large.

The second fiber-reinforced resin of the second layer38includes the second carbon fiber extending along the circumferential direction of the ring member34. Therefore, the second layer38has a larger elastic modulus (rigidity) in the diameter increasing direction than the first layer36. Further, the third fiber-reinforced resin of the third layer40includes the third carbon fiber extending along the circumferential direction of the ring member34. Further, the elastic modulus of the third layer40is larger than the elastic modulus of the second layer38. That is, in the ring member34, the elastic modulus becomes larger as the amount of deformation in the diameter increasing direction when the rotor shaft22is inserted into the ring member34becomes smaller. Therefore, the second layer38and the third layer40are also prevented from breaking when the rotor shaft22is inserted into the ring member34. Further, in the ring member34after being mounted on the rotor shaft22, it becomes possible to satisfactorily hold the permanent magnet30on the outer periphery of the rotor shaft22since the second layer38has a larger elastic modulus than that of the first layer36, and the third layer40has a larger elastic modulus than that of the second layer38.

Therefore, according to the rotor10, the rotary machine12, and the method for manufacturing the rotor10according to this embodiment, the ring member34can be mounted on the rotor shaft22while suppressing the breakage of the ring member34, and the permanent magnet30can be satisfactorily pressed toward the rotor shaft22by the elastic restoring force of the ring member34. As a result, the permanent magnet30can be satisfactorily held on the outer periphery of the rotor shaft22.

In the rotor10according to the above embodiment, the elongation rate of the third layer40is smaller than the elongation rate of the second layer38. In this case, even if the rotor10rotates at high speed and the centrifugal force applied to the permanent magnet30becomes large, the elongation of the third layer40can be suppressed. Therefore, the sleeve32can satisfactorily hold the permanent magnet30on the outer periphery of the rotor shaft22. Further, in the second layer38, in which the amount of deformation in the diameter increasing direction when the ring member34is mounted on the rotor shaft22is larger than that in the third layer40, the elongation rate is larger than that of the third layer40. Therefore, it is possible to prevent the ring member34from breaking when the rotor shaft22is inserted into the ring member34.

In the rotor10according to the above embodiment, when the thickness of the first layer36is 1, the total thickness of the thickness of the second layer38and the thickness of the third layer40is 7.9 to 28.7.

By setting the total thickness to be 7.9 or more when the thickness of the first layer36is set to 1, it is possible to sufficiently secure the thicknesses of the second layer38and the third layer40, which are hoop winding layers showing high strength against the centrifugal force applied to the permanent magnet30when the rotor10is rotated. As a result, the holding force of the permanent magnet30by the sleeve32can be increased.

Further, by setting the total thickness to be 28.7 or less when the thickness of the first layer36is set to 1, it is possible to sufficiently secure the thickness of the first layer36, which is a helical winding layer that is unlikely to break due to deformation of the sleeve32in the diameter increasing direction. As a result, it is possible to effectively prevent the sleeve32from breaking when the sleeve32is attached to the rotor shaft22.

In the rotor10according to the above embodiment, the angle at which the extending direction of the first carbon fiber is inclined with respect to the axis of the rotor shaft22is 30° to 40°.

By setting the inclination angle to 30° or more, the extending direction of the first carbon fiber can be brought closer to the extending direction of the second carbon fiber, and the bonding strength between the first layer36and the second layer38can be increased. In the mounting process, when the inner peripheral surface of the first layer36and the outer peripheral surface of the permanent magnet30are slid, a frictional force is generated between them along the axial direction of the sleeve32. Even in this case, by setting the inclination angle to 30° or more, it is possible to effectively suppress the peeling between the first layer36and the second layer38. As a result, the breakage of the ring member34can be effectively suppressed.

In the mounting process, when a part before diameter increase and a part whose diameter is increased appear in the axial direction of the ring member34, a stress difference (stress distribution) is generated between the part before diameter increase and the part whose diameter is increased. In the first layer36in which the amount of deformation of the ring member34in the diameter increasing direction is large, the above stress difference is also large. By setting the inclination angle to 40° or less, it is possible to suppress the occurrence of shear stress along the orientation direction of the first carbon fiber even if the above stress difference is generated. Therefore, the breakage of the first layer36can be effectively suppressed. As a result, the breakage of the ring member34can be effectively suppressed.

In the rotor10according to the above embodiment, the sleeve32is a cylindrical member having multiple ring members34stacked in the extending direction of the axis of the rotor shaft22. In this case, in the mounting process, it is possible to effectively prevent the ring member34from breaking when the ring member34is pressed in the axial direction in order to mount the ring member34on the rotor shaft22.

That is, in the mounting process, the axial end surface of the ring member34is pressed to slide the inner peripheral surface of the first layer36and the outer peripheral surface of the permanent magnet30. At this time, a frictional force is generated between the inner peripheral surface of the first layer36and the outer peripheral surface of the permanent magnet30. In order to effectively suppress the breakage of the ring member34, it is preferable to reduce the frictional force.

The frictional force increases as the contact area between the inner peripheral surface of the first layer36and the outer peripheral surface of the permanent magnet30increases. Therefore, by mounting the ring member34on the rotor shaft22to form the sleeve32, for example, as compared with the case of mounting a sleeve32which is an integral cylindrical shape longer in the axial direction than the ring member34on the rotor shaft22, the contact area can be reduced to reduce the frictional force. As a result, the breakage of the sleeve32can be effectively suppressed. As a result, the permanent magnet30can be better held on the outer periphery of the rotor shaft22.

As described above, the axial length of each ring member34is preferably 3.3 to 12.0 mm, more preferably 6.0 to 8.0 mm. In this case, even if a shear stress along the axial direction is generated in the ring member34due to the above frictional force, it is possible to effectively suppress the deformation of the ring member34in the axial direction. Therefore, the breakage of the ring member34can be suppressed more effectively.

The rotary machine12according to this embodiment includes the rotor10and the stator18facing the outer periphery of the rotor10at a distance from each other.

In the method for manufacturing the rotor10according to the above embodiment, the sleeve32prepared in the providing process is multiple ring members34, and in the mounting process, the ring members34form the cylindrical sleeve32by being stacked in the extending direction of the axis of the rotor shaft22.

In the method for manufacturing the rotor10according to the above embodiment, there is a jig mounting process of mounting the mounting jig42at one end of the rotor shaft22in the extending direction before the mounting process, and in the mounting process, the rotor shaft22is inserted into the sleeve32via the mounting jig42attached to the rotor shaft22, and the mounting jig42includes the small diameter part46having a diameter smaller than or equal to the inner diameter of the sleeve32before mounted on the rotor shaft22, the large diameter part48having a diameter equal to the outer diameter of the part of the rotor shaft22including the permanent magnet30, and the tapered part50whose diameter is gradually increased from the small diameter part46toward the large diameter part48. In this case, the ring member34elastically deformed in the diameter increasing direction can be easily mounted on the rotor shaft22by a simple configuration in which the mounting jig42is mounted on the rotor shaft22.

The disclosure is not limited to the above-described embodiments, and various configurations may be taken without departing from the gist of the disclosure.

For example, in the above embodiment, multiple ring members34are stacked in the axial direction of the rotor shaft22to form the cylindrical sleeve32, but the disclosure is not particularly limited thereto. The sleeve32may be formed in advance in an integral cylindrical shape. Even in this case, the sleeve32has a first layer36, a second layer38, and a third layer40, similarly to the ring member34. Further, the sleeve32, which has an integral cylindrical shape, may also be disposed on the outer periphery of the permanent magnet30of the rotor shaft22in the same manner as the ring member34.

Although the method for manufacturing the rotor10according to the above embodiment includes a jig mounting process, it does not have to have a jig mounting process. In this case, the sleeve32may be mounted on the rotor shaft22without using the mounting jig42.