Balance adjusting instrument and rotor

Abstract

A balance adjusting instrument according to the present disclosure is attached to a rotating shaft of a rotating body, and comprises: an instrument body which has a cylindrical shape and has a screw hole that opens in the outer circumferential surface, and in which the screw hole and the rotating shaft are arranged in a twisted position relative to each other; and a balance adjusting screw that is retractably screwed into the screw hole.

Description

Balancing tool and rotor

[0001] The present disclosure relates to a balancing tool for adjusting the balance of a rotating body, and a rotor equipped with the balancing tool.

[0002] Conventionally, a balance ring is provided on the rotating shaft to which the rotor is fixed so that the balance of the rotor in a motor can be adjusted. The balance ring has a threaded hole extending along the radial direction of the balance ring. A screw member serving as a weight is screwed into the threaded hole. With this configuration, the balance can be corrected by appropriately changing the distance between the axial center of the balance ring and the screw member.

[0003] Japanese Patent Application Publication No. 10-238594

[0004] In the conventional configuration in which the weight is moved in the radial direction of the balance ring, the cylindrical balance ring needs to be thicker to ensure a large correction amount. In other words, the difference between the outer diameter and the inner diameter of the balance ring needs to be larger. To increase this difference, the outer diameter of the balance ring can be increased or the inner diameter of the balance ring can be reduced.

[0005] Increasing the outer diameter of the balance ring increases the rotational moment, while decreasing the inner diameter of the balance ring reduces the rigidity because the rotating shaft to which the balance ring is fixed becomes thinner.

[0006] In order to solve the above-mentioned problems, a balancing tool and a rotor that can suppress the adverse effects that occur during balance adjustment are desired.

[0007] The balance adjustment device disclosed herein is a balance adjustment device that is attached to the rotation axis of a rotating body, and includes an instrument body having a screw hole that opens on its outer surface, with the screw hole positioned in a twisted position relative to the rotation axis, and a balance adjustment screw that is screwed into the screw hole so that it can move back and forth.

[0008] The rotor of the present disclosure is provided with the balancing tool of the present disclosure described above.

[0009] FIG. 1 is a schematic perspective view showing a balance adjustment tool according to a first embodiment of the present invention, with a portion cut away; FIG. 2 is a schematic cross-sectional view showing a balance adjustment tool according to a first embodiment of the present invention; FIG. 3 is a schematic perspective view showing a state in which the balance adjustment tool according to the first embodiment of the present invention is in use; FIG. 4 is a schematic view showing an example of a rotor to which the balance adjustment tool according to the first embodiment of the present invention is applied; FIG. 5 is an explanatory view showing a state in which balance adjustment has been performed using the balance adjustment tool according to the first embodiment of the present invention; and FIG. 6 is a schematic perspective view showing a state in which the balance adjustment tool according to a second embodiment of the present invention is in use.

[0010] One aspect of the present disclosure will be described below with reference to the drawings. A balance adjustment tool 1 according to a first embodiment of the present invention will be described with reference to Figs. 1 to 4. The balance adjustment tool 1 according to the first embodiment is attached to a rotation shaft of a rotating body and is rotatable integrally with the rotation shaft. The balance adjustment tool 1 includes a cylindrical tool body 2, a male-threaded balance adjustment screw 3, and a male-threaded fixing portion 4.

[0011] The instrument body 2 is cylindrical with both axial ends open. The rotation shaft of the rotating body is passed through the inner hole 5 of the instrument body 2. The instrument body 2 is fixed to the rotation shaft with the rotation shaft passing through the inner hole 5. Therefore, the instrument body 2 can rotate integrally with the rotation shaft of the rotating body (for example, the shaft 15 described below). Note that the instrument body 2 is not limited to a cylindrical shape, and may have any configuration that allows it to be fixed to the rotation shaft of the rotating body so as to be rotatable integrally with it.

[0012] The instrument body 2 has a threaded hole 6 that opens onto the outer peripheral surface. In the illustrated example, both axial ends of the linear threaded hole 6 open onto the outer peripheral surface of the instrument body 2. In other words, the threaded hole 6 penetrates the instrument body 2. The threaded hole 6 does not open onto the inner peripheral surface of the inner hole 5 of the instrument body 2. The threaded hole 6 is located outside the inner hole 5 of the instrument body 2 and does not intersect with the inner hole 5. The threaded hole 6 is not parallel to the rotation axis that penetrates the instrument body 2 and does not intersect with it. In this way, the threaded hole 6 is positioned at a position twisted relative to the rotation axis. The threaded hole 6 is female-threaded, with threads formed on the inner peripheral surface of the hole.

[0013] In the first embodiment, the instrument body 2 has a plurality of (four in the first embodiment) screw holes 6. Typically, as shown in FIG. 2 , the instrument body 2 has screw hole groups 7, 8, each including a pair of screw holes 6. Of the four screw holes 6, a pair of screw holes 6, 6 constitutes one screw hole group 7. Of the four screw holes 6, another pair of screw holes 6, 6 constitutes the other screw hole group 8. The instrument body 2 has a pair of screw hole groups 7, 8 configured in this way. Of the pair of screw hole groups 7, 8, a pair of screw holes 6, 6 included in one screw hole group 7 are arranged in a parallel relationship. The pair of screw holes 6, 6 are arranged spaced apart in the radial direction of the instrument body 2. The pair of screw holes 6, 6 are arranged so as to sandwich the inner hole 5 of the instrument body 2. Of the pair of screw hole groups 7, 8, a pair of screw holes 6, 6 included in the other screw hole group 8 are arranged in a parallel relationship. The pair of screw holes 6, 6 are arranged spaced apart in the radial direction of the instrument body 2. The pair of screw holes 6, 6 are arranged so as to sandwich the inner hole 5 of the instrument body 2 therebetween.

[0014] Of a pair of screw holes 6, 6 included in one screw hole group 7, one screw hole 6 is arranged perpendicular to both of a pair of screw holes 6, 6 included in the other screw hole group 8. Of a pair of screw holes 6, 6 included in one screw hole group 7, the other screw hole 6 is arranged perpendicular to both of a pair of screw holes 6, 6 included in the other screw hole group 8. Therefore, in the first embodiment, the four screw holes 6 provided in the instrument body 2 are arranged in a substantially rectangular frame shape so as to surround the inner hole 5 of the instrument body 2. In this way, each pair of screw holes 6, 6 included in one screw hole group 7 is arranged perpendicular to each of the pairs of screw holes 6, 6 included in the other screw hole group 8.

[0015] As shown in Figures 1 and 3, the instrument body 2 has mounting portions 9 for the fixing portions 4, which will be described later. The instrument body 2 has four screw holes 6 as described above, and therefore has four mounting portions 9. The four mounting portions 9 are arranged on the instrument body 2 so that one mounting portion 9 corresponds to one screw hole 6. In the illustrated example, the mounting portions 9 are screw holes that are open at both axial ends. The mounting portions 9 open at one axial end face of the instrument body 2 and also open to the inner circumferential surface of the screw hole 6. Therefore, the mounting portions 9 communicate with the screw hole 6. The mounting portions 9 are female-threaded, with threads formed on the inner circumferential surface of the hole.

[0016] The balance adjustment screw 3 is a male screw with threads formed on the outer circumferential surface of a rod material. In the illustrated example, the balance adjustment screw 3 is a fully threaded stud bolt. The balance adjustment screw 3 is attached to the instrument body 2 by screwing it into the threaded hole 6 of the instrument body 2. With this configuration, the balance adjustment screw 3 is screwed into the threaded hole 6 of the instrument body 2 so that it can move back and forth. When the balance adjustment screw 3 is screwed into the threaded hole 6, the balance adjustment screw 3 can move along the threaded hole 6 and can be held at any position in the axial direction of the threaded hole 6.

[0017] The fixing portion 4 is a male-threaded rod having a thread formed on the outer circumferential surface thereof. In the illustrated example, the fixing portion 4 is a fully threaded stud bolt. The fixing portion 4 is screwed into the mounting portion 9 from an opening located on one axial end face of the device body 2.

[0018] Next, use of the balancing tool 1 of the first embodiment will be described with reference to Figures 3 to 5. The balancing tool 1 of the first embodiment is applied to, for example, an electric motor 10. The electric motor 10 includes a rotor 11, a stator 12, and a housing 13. The balancing tool 1 is applied to the rotor 11 of the electric motor 10. Note that, hereinafter, the axial direction of the electric motor 10 is defined as an axial direction J1.

[0019] The rotor 11 includes a balancing tool 1, a rotor core 14, a plurality of magnets (not shown), and a shaft 15. The rotor core 14 is cylindrical with both ends open in the axial direction J1 and has a structure including a plurality of electromagnetic steel plates 16 stacked in the axial direction J1. The magnets are housed in a plurality of housing portions (not shown) formed in the rotor core 14. A pair of disk-shaped end plates 17, 17 are disposed on both ends of the rotor core 14 in the axial direction J1. The disk-shaped end plate 17 has a circular insertion hole 18 at its center that penetrates in the axial direction J1. With the magnets disposed in the housing portions, the rotor core 14 is fixed between the pair of end plates 17, 17 with bolts or the like.

[0020] The shaft 15 is, for example, rod-shaped and extends in the axial direction J1. The rotor core 14 is fixed to the shaft 15 so as to be rotatable integrally with the shaft 15, with the shaft 15 passing through an inner hole 19 of the rotor core 14 and through holes 18 of the pair of end plates 17, 17. The balancing tool 1 is fixed to one end of the shaft 15 in the axial direction J1 so as to be rotatable integrally with the shaft 15, with the shaft 15 passing through the inner hole 5 of the tool body 2.

[0021] The rotor 11 configured as described above is disposed inside a cylindrical stator 12. The stator 12 has a stator core 20 and a coil 21. The stator core 20 is cylindrical with both ends in the axial direction J1 open, and has a structure including a plurality of electromagnetic steel plates 22 stacked in the axial direction J1. The stator core 20 has a plurality of teeth (not shown) that protrude radially inward from its inner circumferential surface. A coil 21 is attached to each of the plurality of teeth.

[0022] The housing 13 is cylindrical with both ends in the axial direction J1 open. The housing 13 has a square cylindrical outer shape and an inner circumferential surface with a circular cross section. The stator 12 is fixed to the housing 13 with the outer circumferential surface of the stator 12 in contact with the inner circumferential surface of the housing. The opening on one end of the housing 13 in the axial direction J1 is closed by a cover member 23. A bearing (not shown) is provided in the cover member 23. The opening on the other end of the housing 13 in the axial direction J1 is closed by a cover member (not shown). A bearing (not shown) is provided in the cover member.

[0023] One axial end of the shaft 15 in the axial direction J1 is held in a bearing provided in the cover member 23 located on one end side of the housing 13 in the axial direction J1, and the other axial end of the shaft 15 in the axial direction J1 is held in a bearing provided in the cover member located on the other end side of the housing 13 in the axial direction J1. In this way, the rotor 11 is held in the housing 13 so as to be rotatable about the axis of the shaft 15. As shown in Figure 3, when the rotor 11 is held in the housing 13, one axial end of the shaft 15 of the rotor 11 in the axial direction J1 is exposed to the outside of the housing 13 through a through-hole in the cover member 23. The balance adjustment tool 1 is attached to this exposed portion.

[0024] Next, an example of a balance adjustment method using the balance adjustment tool 1 of this embodiment 1 will be described with reference to Fig. 5. When adjusting the balance, first, the balance adjustment screw 3 of the balance adjustment tool 1 attached to the shaft 15 of the rotor 11 is set to an initial state position. Here, the initial state position is when the balance adjustment screw 3 is located at the axial center of the screw hole 6, as shown in Fig. 2. In this state, the electric motor 10 is driven, and the adjustment amount is obtained using a conventionally known method.

[0025] Here, as shown in Figure 5, a case will be described in which a mass is added to a position that is offset by x in the X direction and by y in the Y direction from the axial center of the shaft 15. Normally, when the electric motor 10 is driven, vibration occurs in the electric motor 10 due to mechanical errors of the electric motor 10. To suppress this vibration, a minute mass is added as described above.

[0026] To add mass, the balance adjustment screws 3 threaded into the screw holes 6 of the screw hole group 7 are moved by a distance x in the X direction, and the balance adjustment screws 3 threaded into the screw holes 6 of the screw hole group 8 are moved by a distance y in the Y direction. When performing balance adjustment, the balance adjustment tool 1 is rotated around the shaft 15 to adjust the eccentricity, as shown in FIG. 3 . Furthermore, the multiple balance adjustment screws 3 inserted into the same screw hole group do not necessarily need to be moved the same distance. For example, when moving by a distance x in the X direction, the combination of the movement distances of the balance adjustment screws 3 can be freely selected so that the total movement distance of the corresponding multiple balance adjustment screws 3 is x. The same applies when moving the balance adjustment screws 3 by a distance y in the Y direction.

[0027] After the balance adjustment screw 3 has been moved to a predetermined position, the fixing portion 4 is screwed into the mounting portion 9 of the instrument body 2. The fixing portion 4 is screwed into the mounting portion 9 until it contacts the balance adjustment screw 3 in the screw hole 6. The fixing portion 4 presses against the balance adjustment screw 3, thereby more reliably holding the balance adjustment screw 3 in the desired position. In this way, the fixing portion 4 can fix the balance adjustment screw 3 screwed into the screw hole 6 at any position. In this embodiment 1, the length of the balance adjustment screw 3 is adjusted so that the fixing portion 4 can contact the balance adjustment screw 3. In other words, the length of the balance adjustment screw 3 is such that it is positioned on the extension of the mounting portion 9 when it is located at the extreme end of the screw hole 6.

[0028] In the first embodiment, the threaded hole 6 into which the balance adjustment screw 3 is screwed is positioned skewed relative to the shaft 15. Therefore, according to the first embodiment, balance can be adjusted by appropriately adjusting the position of the balance adjustment screw 3. In contrast to this, conventionally, threaded holes are radially formed on the instrument body. In this case, the amount of adjustment is limited by the difference between the outer diameter and inner diameter of the instrument body. However, in the first embodiment, the threaded hole 6 is configured to be skewed relative to the shaft 15, so the length of the threaded hole 6 can be increased, allowing for a wider range of adjustment.

[0029] In the case of the first embodiment, the balance adjustment tool 1 is provided with a fixing portion 4 that fixes the balance adjustment screw 3. Therefore, according to the first embodiment, the balance adjustment screw 3 can be more reliably held in the position after the balance adjustment.

[0030] Next, a balance adjustment tool 1a according to the second embodiment will be described with reference to Fig. 6. Note that components having the same reference numerals as those in the first embodiment have the same functions, and therefore, their descriptions will be omitted below.

[0031] The balance adjustment tool 1a of the second embodiment differs from that of the first embodiment in the configuration of the tool body 2. Specifically, the tool body 2 does not have the mounting portion 9 of the fixing portion 4. Therefore, the balance adjustment tool 1a of the second embodiment does not have the fixing portion 4 for fixing the balance adjustment screw 3. In the case of the balance adjustment tool 1a of the second embodiment, the balance adjustment screw 3 is fixed to the tool body 2 with an adhesive in order to fix the balance adjustment screw 3 in its position after balance adjustment.

[0032] According to at least one of the embodiments described above, the threaded holes 6 into which the balance adjustment screws 3 are screwed are arranged in a twisted position relative to the shaft 15. Therefore, it is possible to provide a balance adjustment device 1, 1a and a rotor 11 that can suppress adverse effects that occur when adjusting the balance, compared to when the threaded holes 6 are arranged radially.

[0033] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments.

[0034] For example, in the first and second embodiments, the instrument body 2 has four screw holes 6, but this is not limited thereto, and it is preferable that the instrument body 2 has a plurality of screw holes 6. For example, the number of screw holes 6 may be three. In this case, it is preferable that the three screw holes 6 are arranged in a substantially triangular frame shape so as to surround the inner hole 5 of the instrument body 2. The number of screw holes 6 may be two. In this case, it is preferable that the two screw holes 6 are arranged in a substantially L-shape outside the inner hole 5 of the instrument body 2.

[0035] In the first embodiment, the instrument body 2 is provided with one mounting portion 9 for one screw hole 6, but this is not limited to this, and multiple mounting portions 9 may be provided for one screw hole 6. In this case, the multiple mounting portions 9 are arranged along the axial direction of the screw hole 6. This makes it possible to select an appropriate mounting portion 9 from the multiple mounting portions 9 when fixing the balance adjustment screw 3 with the fixing portion 4.

[0036] In the first and second embodiments, the instrument body 2 has a pair of screw hole groups 7 and 8, but it may have only one of the screw hole groups 7.

[0037] The following supplementary notes are further disclosed regarding the above embodiment: (Supplementary Note 1) The balance adjustment tool (1) is a balance adjustment tool to be attached to the rotation shaft of a rotating body, and includes a tool body (2) having a screw hole (6) opening on its outer peripheral surface, the screw hole (6) being disposed in a twisted position relative to the rotation shaft, and a balance adjustment screw (3) that is threaded into the screw hole (6) so as to be able to advance and retreat.

[0038] (Supplementary Note 2) The balance adjustment tool (1) in Supplementary Note 1 may have a screw hole group (7) including a pair of the screw holes (6), and the pair of screw holes (6, 6) may be arranged in a parallel relationship to each other.

[0039] (Supplementary Note 3) In Supplementary Note 2, the balancing device (1) may have a pair of screw hole groups (7, 8), and the screw holes (6, 6) included in one of the screw hole groups (7) may be arranged perpendicular to the screw holes (6, 6) included in the other of the screw hole groups (8).

[0040] (Appendix 4) In any of Appendices 1 to 3, the balance adjustment device (1) may further include a fixing portion (4) that fixes the balance adjustment screw (3) screwed into the screw hole (6) at any position.

[0041] (Supplementary Note 5) The rotor (11) is provided with the balancing tool (1) according to any one of Supplementary Notes 1 to 4.

[0042] REFERENCE SIGNS LIST 1 Balance adjustment tool 2 Tool body 3 Balance adjustment screw 4 Fixing part 6 Screw hole 7 Screw hole group 8 Screw hole group 11 Rotor

Claims

1. A balance adjustment device to be attached to the rotation shaft of a rotating body, comprising: a device body having a screw hole opening on its outer peripheral surface, the screw hole being positioned at a twisted position relative to the rotation shaft; and a balance adjustment screw that is threaded into the screw hole so as to be able to advance and retreat.

2. The balancing tool according to claim 1, further comprising a group of screw holes including a pair of said screw holes, said pair of screw holes being arranged in a parallel relationship with each other.

3. A balancing tool as described in claim 2, which has a pair of screw hole groups, and each of the screw holes included in one of the screw hole groups is arranged in a mutually perpendicular relationship with each of the screw holes included in the other of the screw hole groups.

4. A balancing tool according to any one of claims 1 to 3, further comprising a fixing portion for fixing the balancing screw threaded into the screw hole at any position.

5. A rotor equipped with a balancing tool according to any one of claims 1 to 4.

Images