JP2013211934A - Electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce distortion in a spigot part of a bracket in an electric motor.SOLUTION: An electric motor includes a casing 2 which houses a driving section therein, and a bracket 3 which is fastened to one end in an axial direction of the casing 2 via a plurality of screws 14 and is fitted in a fitting hole of a fixing object member to allow the bracket to be centered in a radial direction to the fixing object member. The bracket 3 includes a spigot part 8 to be fitted in the fitting hole, spigot surfaces 31a to 31d which are provided to an outer periphery of the spigot part 8 and contribute to the centering, and non-spigot surfaces 32a to 32d which do not contribute to the centering. The non-spigot surfaces 32a to 32d are formed with surfaces more concave in the radial direction than the spigot surfaces 31a to 31d.

Description

  The present invention relates to an electric motor.

Some electric motors include a cylindrical casing that houses a drive unit therein, and a bracket connected to one end of the casing, and an output shaft projects from a hole provided in the bracket. .
Many of this type of electric motor have a plurality of flanges protruding from the outer periphery of the bracket in the radial direction to be fixed to a fixed member to which the electric motor is attached, and bolt insertion holes are provided in the flange. It has been. Then, the electric motor is fixed to the fixed member by abutting the flange portion with the fixed member, inserting the bolt into the bolt insertion hole, and screwing the bolt into the screw hole of the fixed member (for example, Patent Document 1).

  In addition, as shown in FIG. 6, the electric motor 100 has a casing 101 housed in a motor housing hole 201 of the fixed member 200 and mounted on the inlet side of the motor housing hole 201 as an attachment form of the electric motor to the fixed member. There is a type of fixing the electric motor 100 to the fixed member 200 by fitting the inlay portion 103 of the bracket 102 serving as the centering portion on the electric motor 100 side into the provided engaging hole 202 for centering. (Hereinafter, the electric motor having such an attachment form is referred to as an inlay type electric motor.) In the case of this inlay type electric motor 100, the outer peripheral surface of the inlay portion 103 is the outermost peripheral portion of the electric motor 100, and Is not provided with a plurality of flange portions protruding outward in the radial direction as described above, and the outer peripheral surface of the spigot portion 103 of the bracket 102 is formed in a true circle when viewed from the axial direction of the output shaft 104.

JP 2007-300764 A

  By the way, in the inlay type electric motor 100, the flange portion of the casing 101 is fixed at two positions 180 degrees apart in the circumferential direction to fix the casing 101 to the bracket 102 as shown in FIGS. It has been confirmed that when the screw 105 inserted into 104 is screwed into the screw hole 106 of the bracket 102 and tightened, the inlay portion 103 of the bracket 102 is partially distorted in the radial direction due to the tightening stress. 7 and 8, reference numeral 107 denotes a notch formed in the bracket 102, and the coupler 108 is inserted into the notch 107 as shown in FIG.

The radial distortion of the inlay portion 103 will be described in detail. As shown in FIG. 8, in the inlay portion 103, in the vicinity of the fastening portion by the screw 105, it is reduced in the radial direction (that is, the diameter is reduced), and from the fastening portion in the circumferential direction. Since the portion that is separated by 90 degrees and the vicinity thereof expand in the radial direction (that is, increase in diameter), the roundness of the outer peripheral surface of the spigot portion 103 decreases.
Thus, when the roundness of the outer peripheral surface of the spigot portion 103 of the bracket 102 decreases, the diameter of the electric motor 100 with respect to the fixed member 200 when the spigot portion 103 is fitted into the engagement hole 202 of the fixed member 200. The centering accuracy in the direction is reduced.

  As a method of improving the roundness of the outer peripheral surface of the inlay portion 103 of the bracket 102, there is a method of increasing the number of fastening portions between the casing and the bracket (that is, the number of screws 105). If there are design restrictions, the position and number of fastening portions may not be set freely.

  Therefore, the present invention provides an electric motor that can reduce the distortion in the radial direction of the inlay portion of the bracket even when there is a design restriction.

The electric motor according to the present invention employs the following means in order to solve the above problems.
According to the first aspect of the present invention, the casing in which the drive unit is accommodated is fastened to the axial end of the casing via a plurality of fastening members, and is inserted into the engagement hole of the fixed member. A bracket that enables centering in a radial direction with respect to the fixed member, and the bracket is provided with an inlay portion that is fitted into the engagement hole, and an outer peripheral surface of the inlay portion, An electric motor characterized in that a contributing inlay surface and a non-inlay surface that does not contribute to the centering are formed, and the non-inlay surface is formed as a surface recessed in a radial direction from the inlay surface. It is.
Since only the inlay surface contributes to centering in the inlay portion of the bracket, only the inlay surface needs to be measured when measuring the roundness, and there is no need to measure the non-inlay surface. Further, when the roundness is finely adjusted, it is only necessary to process the inlay surface, and it is not necessary to process the non-inlay surface. As a result, the management man-hour for roundness can be reduced. Moreover, the distortion of the bracket outer diameter after the casing is fastened to the bracket can be suppressed, and the accuracy of the roundness on the spigot surface of the spigot portion is easily obtained.

The invention according to claim 2 is the invention according to claim 1, wherein the bracket is formed so as to protrude from a side away from the casing from the inlay portion, and the inlay portion and the inflated portion. It is characterized by comprising a plurality of ribs provided in a step portion with respect to the portion.
Since a plurality of ribs are provided at the step portion between the spigot portion and the bulge portion, distortion of the bracket outer diameter after the casing is fastened to the bracket can be further suppressed, and the roundness of the spigot surface of the spigot portion can be reduced. Accuracy is easily obtained.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the non-inlay surface is disposed at least radially outward of a fastening portion formed by the fastening member.
When the casing is fastened to the bracket, the distortion in the bracket radial direction increases at the radially outer position of the fastening portion. However, by arranging a non-inlay surface in that portion, the distortion in the bracket radial direction on the inlay surface results. The roundness accuracy on the inlay surface can be easily obtained.

The invention according to claim 4 is the invention according to claim 1 or 2, wherein the bracket is provided with a plurality of fastening portions by the fastening members, and the non-inlay surface is at least two adjacent to each other. It arrange | positions at the radial direction outer side of the circumferential direction intermediate position between fastening parts, It is characterized by the above-mentioned.
When the casing is fastened to the bracket, the distortion in the bracket radial direction increases at the radially outer position at the circumferential intermediate position between the two fastening portions. Further, the distortion in the bracket radial direction on the inlay surface can be suppressed, and the roundness accuracy on the inlay surface can be easily obtained.

According to a fifth aspect of the present invention, in the invention according to any one of the second to fourth aspects, the inlay portion of the bracket includes a notch portion that opens to an outer peripheral side, and the notch portion is It is arranged at the same position in the circumferential direction as the non-inlay surface.
The notch is originally a part that does not contribute to roundness, and the notch and the non-inlay surface are arranged at the same position in the circumferential direction, so that the notch is provided in a different part from the non-inlay surface Compared to the above, a large area of the inlay surface can be secured.

According to the first aspect of the present invention, the distortion of the bracket outer diameter after the casing is fastened to the bracket can be suppressed, and the accuracy of the roundness on the spigot surface of the spigot part can be easily obtained. In addition, the management man-hour for roundness can be reduced.
According to the invention which concerns on Claim 2, the precision of the roundness in an inlay surface becomes easy to come out.
According to the invention which concerns on Claim 3 or Claim 4, the distortion of the bracket radial direction in an inlay surface can be suppressed, and the precision of the roundness in an inlay surface becomes easy to come out.
According to the invention which concerns on Claim 5, the area | region of an inlay surface can be ensured large.

It is the external appearance perspective view which looked at the electric motor in embodiment of this invention from the bracket side. It is the external appearance perspective view which looked at the electric motor in an embodiment from the casing side. It is a disassembled perspective view of the electric motor in an embodiment. It is the front view which looked at the electric motor in an embodiment from the bracket side. It is the rear view which looked at the electric motor in an embodiment from the casing side. It is sectional drawing which shows the attachment state of an electric motor. It is a disassembled perspective view of the conventional electric motor. It is the rear view which looked at the conventional electric motor from the casing side.

Embodiments of an electric motor according to the present invention will be described below with reference to the drawings of FIGS.
FIG. 1 is an external perspective view of an electric motor 1 according to an embodiment of the present invention as viewed from the bracket 3 side, and FIG. 2 is an external perspective view of the electric motor 1 as viewed from the casing 2 side.
The electric motor 1 has one end opened and the other end closed to form a substantially cylindrical shape. The casing 2 accommodates a drive unit (not shown) such as a rotor inside, and is fixed to the end of the casing 2 on the opening side. A bracket 3 that closes the opening is provided, and an output shaft 4 (see FIG. 4) of a rotor (armature) (not shown) projects outside through a hole formed in the center of the bracket 3. In FIG. 1, a gear portion 4a provided integrally with the output shaft 4 is shown.

  Referring to FIG. 6, the attachment form of the electric motor 1 to the fixed member 200 will be described. The electric motor 1 is configured by inserting the casing 2 into the motor housing hole 201 formed in the fixed member 200 and fixing the electric motor 1. The bracket 3 is fitted into an engagement hole 202 formed on the inlet side of the motor accommodation hole 201 in the member 200 and having a larger inner diameter than the motor accommodation hole 201, and the surface of the bracket 3 on the casing 2 side is the bottom surface of the engagement hole 202. It is used by being fixed to the fixed member 200 while being in contact with 202a.

  The electric motor 1 is centered in the radial direction with respect to the fixed member 200 by fitting the bracket 3 into the engagement hole 202, and the surface of the bracket 3 on the casing 2 side is set to the bottom surface 202 a of the engagement hole 202. By abutting, positioning in the axial direction with respect to the fixed member 200 is performed. Therefore, in this electric motor 1, the roundness of the outer peripheral surface of the bracket 3 is extremely important.

  As shown in FIGS. 2, 3, and 5, the casing 2 has an annular end surface portion 5 projecting radially outward at an end portion on the opening side, and a plurality of locations (this embodiment) Then, flange portions 6 projecting outward in the radial direction are provided at positions at two positions separated from each other by 180 degrees in the circumferential direction. A screw insertion hole 7 is formed in each flange portion 6.

  The bracket 3 includes an inlay portion 8 disposed on the casing 2 side, and a bulging portion 9 formed so as to protrude to the side farther from the casing 2 than the inlay portion 8, and the inlay portion 8 and the bulging portion 9 are connected by a step 10. FIG. 4 is a front view of the electric motor 1 as viewed from the bracket 3 side. As shown in FIG. 4, the outer peripheral surface 8 a of the spigot portion 8 has a substantially circular shape when viewed from the front. On the other hand, the bulging portion 9 is a portion in which a brush holder for supplying electric power to the rotor of the electric motor 1, a bearing for supporting the output shaft 4, and the like are provided, and is located on the radially inner side of the spigot portion 8. Thus, any portion of the bulging portion 9 does not protrude outward in the radial direction from the spigot portion 8.

  As shown in FIG. 3, the back surface (surface on the casing 2) 8b of the spigot portion 8 is formed in a substantially annular flat surface, and the end surface portion 5 and the flange portion 6 of the casing 2 are in contact with the back surface 8b. It comes to touch.

  A cutout portion 11 is formed at one place in the circumferential direction of the inlay portion 8 so as to be cut out in a rectangular shape radially outward from the outer peripheral surface 8a (opening to the outer peripheral side). The end portion in the direction reaches the bulging portion 9. As shown in FIGS. 1 and 2, the notch portion 11 becomes a space into which the coupler portion 12 is inserted.

  A screw hole 13 for fixing the casing 2 is formed at a position in the inlay portion 8 that is 90 degrees apart from the notch portion 11 on both sides in the circumferential direction. The casing 2 is fixed to the bracket 3 by inserting a screw (fastening member) 14 through a screw insertion hole 7 provided in the flange portion 6 of the casing 2 and further screwing and tightening the screw 14 into the screw hole 13 of the bracket 3. Will be. In this embodiment, the part fastened by the screw 14 becomes a fastening part.

  The bulging portion 9 includes bulging portions 15, 16, and 17 that bulge outward in the radial direction and extend the tip to the vicinity of the outer peripheral surface 8 a of the spigot portion 8. The overhang portions 15 and 16 are provided on both sides of the notch portion 11 at positions separated from the notch portion 11 by a predetermined dimension, and the overhang portion 17 is located at a position spaced apart from the notch portion 11 by about 180 degrees in the circumferential direction. Is provided.

  Further, the inlay portion 8 and the bulging portion 9 are connected by a plurality of (four in this embodiment) ribs 21, 22, 23, and 24 provided in the stepped portion 10. The ribs 21 and 22 are provided so as to span the edge of the notch portion 11 and the side surfaces of the overhang portions 15 and 16 in the inlay portion 8, and the ribs 23 and 24 are overhang portions from the screw holes 13 in the circumferential direction. 17 is provided at a position spaced apart by a predetermined angle in a direction approaching 17.

The inlay portion 8 of the bracket 2 has a function of centering in the radial direction with respect to the fixed member 200 of the electric motor 1 by being fitted into the engaging hole 202 of the fixed member 200 shown in FIG. 6 as described above. .
A plurality (four in this embodiment) of the inner surface 8a of the inlay portion 8 contributes to the centering by contacting the inner peripheral surface of the engagement hole 202 when fitted into the engagement hole 202. A plurality (four in this embodiment) that do not contribute to the centering because they do not contact the inner peripheral surface of the engagement hole 202 when fitted to the engagement holes 202 and the inlay surfaces 31a, 31b, 31c, 31d. The non-inlay surfaces 32a, 32b, 32c, and 32d are alternately formed in the circumferential direction. In other words, on the outer peripheral surface 8a of the inlay portion 8, the inlay surfaces (31a to 31d) that contribute to the centering are divided into a plurality of parts.

More specifically, the non-inlay surfaces 32a and 32b are arranged at positions corresponding to the outer sides in the radial direction of the respective screw holes 13, and the non-inlay surface 32c is arranged at the same position in the circumferential direction as the notch portion 11, and the non-inlay surface 32d. Is formed at a position 180 degrees away from the notch 11 in the circumferential direction. In other words, the non-inlay surfaces 32a to 32d are arranged at the radially outer side of the fastening portion by the screw 14 and at the circumferential intermediate position between the two fastening portions adjacent to each other. The notch 11 is formed in the circumferential region of the non-inlay surface 32c, and the circumferential length of the non-inlay surface 32c is longer than the circumferential length of the notch 11.
One inlay surface 31a, 31b, 31c, 31d is provided between each non-inlay surface 32a, 32b, 32c, 32d.

  The inlay surfaces 31 a to 31 d and the non-inlay surfaces 32 a to 32 d are all formed by arcuate surfaces that are concentric with the central axis of the output shaft 4. The outer diameters of the inlay surfaces 31a to 31d are formed to have the same diameter. The outer diameters of the non-inlay surfaces 32a to 32d are formed to have the same diameter that is smaller than the outer diameter of the inlay surfaces 31a to 31d. That is, the non-inlay surfaces 32a to 32d are formed as surfaces that are recessed by a predetermined dimension in the radial direction from the inlay surfaces 31a to 31d. In this way, the non-inlay surfaces 32a to 32d are formed so as to be recessed in the radial direction from the inlay surfaces 31a to 31d, so that the non-inlay surfaces 32a to 32d do not contribute to centering.

  Further, the above-described bulging portion 15 of the bulging portion 9 is disposed on the inner side of the inlay surface 31a, and the above-described bulging portion 16 of the bulging portion 9 is disposed on the inner side of the inlay surface 31b in the radial direction. The ribs 23 and 24 described above are disposed inside the inlay portions 31c and 31d.

  In the electric motor 1 configured as described above, in order to fix the casing 2 to the bracket 3, the screw 14 is inserted into the screw insertion hole 7 provided in the flange portion 6 of the casing 2, and the screw 14 is further inserted into the bracket 3. The screw hole 13 is screwed and tightened. When the casing 2 is fastened to the bracket 3 at two points in this way, as shown in FIG. 5, the spigot portion 8 is radially reduced in the vicinity of the fastening portion (in other words, the screw hole 13), and the circumferential direction from the fastening portion. The spigot portion 8 expands in the radial direction at a portion that is 90 degrees apart. Further, radial distortion is less likely to occur at the intermediate portion in the circumferential direction between the reduced diameter portion and the expanded diameter portion.

  In the inlay portion 8 of the bracket 3 in the electric motor 1, the non-inlay surfaces 32a to 32d that do not contribute to the centering function are arranged in the portion where the radial distortion is likely to occur, and the radial distortion is not easily generated. Furthermore, since the inlay surfaces 31a to 31d that contribute to the centering function are arranged, the accuracy of the roundness of the inlay surfaces 31a to 31d after the casing 2 is fastened to the bracket 3 is easily obtained.

  In addition, ribs 23 and 24 are provided radially inward of the inlay surfaces 31c and 31d, and overhang portions 15 and 16 of the bulging portion 9 are provided in the radial inside of the inlay surfaces 31a and 31b. Since 15 and 16 function as ribs, it is possible to prevent the inlay surfaces 31a to 31d from being distorted in the radial direction. This also facilitates the accuracy of roundness on the inlay surfaces 31a to 31.

  Moreover, since the ribs 21 and 22 are provided also in the vicinity of the notch part 11, the rigidity around the notch part 11 is improved. As a result, it is possible to suppress radial distortion at the spigot surfaces 31a and 31b disposed on both sides of the cutout portion 11. This also facilitates the accuracy of roundness in the inlay surfaces 31a to 31d.

  In addition, since only the spigot surfaces 31a to 31d are the surfaces that contribute to the centering in the spigot portion 8, only the spigot surfaces 31a to 31d have to be measured when measuring the roundness, and the non spigot surfaces 32a to 32d are measured. There is no need to measure. Furthermore, when the roundness is finely adjusted, only the inlay surfaces 31a to 31d need be processed, and the non-inlay surfaces 32a to 32d need not be processed. As a result, the management man-hour for the roundness of the inlay portion 8 can be reduced.

  Further, the notched portion 11 in the spigot portion 8 is originally a portion that does not contribute to roundness, and the notched portion 11 is not non-circulated by disposing the notched portion 11 at the same position in the circumferential direction as the non-inlay surface 31a. Compared with the case where it is provided in a part different from the inlay surfaces 31a to 31d, it is possible to ensure a large area (circumferential length) of the inlay surfaces 31a to 31d.

[Other Examples]
The present invention is not limited to the embodiment described above.
For example, the number of inlay surfaces and non-inlay surfaces formed on the outer peripheral surface of the inlay portion is not limited to four, and may be four or more.
Moreover, a fastening part is not restricted to two places, Three places may be sufficient.
The fastening member is not limited to a screw, and may be a bolt / nut.

DESCRIPTION OF SYMBOLS 1 Electric motor 2 Casing 3 Bracket 8 Inlay part 9 Swelling part 10 Step part 11 Notch part 14 Screw (fastening member)
21-24 Ribs 31a-31d Inlay surface 32a-32d Non-inlay surface 200 Fixed member 202 Engagement hole

Claims (5)

A casing containing the drive unit inside,
A bracket that is fastened to one end in the axial direction of the casing via a plurality of fastening members, and that is fitted into an engagement hole of the fixed member, thereby enabling radial alignment with respect to the fixed member;
With
The bracket is formed with an inlay portion that is fitted into the engagement hole, an inlay surface that is provided on an outer peripheral surface of the inlay portion and contributes to the centering, and a non-inlay surface that does not contribute to the centering. The electric motor is characterized in that the non-inlay surface is formed as a surface recessed in a radial direction with respect to the inlay surface.   The bracket includes a bulging portion that is formed to protrude from the inlay portion toward the side away from the casing, and a plurality of ribs provided at a step portion between the inlay portion and the bulging portion. The electric motor according to claim 1.   The electric motor according to claim 1, wherein the non-inlay surface is disposed at least on a radially outer side of a fastening portion formed by the fastening member.   The bracket is provided with a plurality of fastening portions by the fastening member, and the non-inlay surface is disposed at a radially outer side at a circumferential intermediate position between at least two fastening portions adjacent to each other. The electric motor according to claim 1 or 2, characterized in that   The notched part opened to an outer peripheral side is provided in the inlay part of the said bracket, and the said notch part is arrange | positioned in the same position of the said non-inlay surface in the circumferential direction. The electric motor according to any one of the above.

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