Electric Motor

Abstract

To provide an electric motor equipped with a cooling fan in which a structure for attaching a fan cover is simplified and the attachment workability is improved.SOLUTION: An electric motor according to an embodiment includes an electric motor body having, on the front and rear surfaces of a tubular frame, motor brackets for supporting a rotary shaft, a cooling fan that is disposed on a portion projected rearward from the motor bracket disposed on the rear portion of the rotary shaft, and a fan cover that has a cylindrical shape the front surface of which is open, and is disposed on the rear portion of the electric motor body so as to cover the cooling fan. The fan cover is positioned on the opening end side, is provided with an engagement hole, and has a protruding engagement projection on the outer circumferential surface of the rear end of the frame or on the outer circumferential surface of the motor bracket disposed on the rear portion. The engagement hole is engaged, at three or more points on the circumferential direction, with the engagement projection so that the opening end of the fan cover is attached so as to cover the outer circumference surface of the rear end of the electric motor body.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] An embodiment of the present invention relates to an electric motor equipped with a cooling fan. [Background technology]

[0002] For example, as an electric motor for various industrial equipment, there is one which is provided with a cooling fan attached to a rotating shaft at the rear of the electric motor body, and the cooling fan part is covered with a circular lid-shaped fan cover (see, for example, Patent Document 1). The electric motor body is constructed by attaching a motor bracket to both the front and rear ends of a cylindrical frame by bolting, and a plurality of heat dissipation fins and a plurality of mounting seats for bolting the motor bracket are provided on the outer periphery of the frame. At this time, the plurality of mounting seats on the rear side are provided with screw holes that open in the outer periphery direction. The fan cover is arranged so that its open end covers the outer periphery of the rear end of the frame, and is attached by screws being fastened to the screw holes of the mounting seats through screw insertion holes provided at, for example, three or four places in the circumferential direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-146346 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-mentioned fan cover mounting structure has the following problems. That is, when an operator screws the fan cover, the process of aligning and tightening the screws is required, making the work relatively troublesome. Since multiple screws are used, the number of parts is large, and tools are also required. There is also a risk that the operator will forget to tighten some of the screws, and the tightening force can vary depending on the operator's level of skill, for example. In view of the above, an electric motor equipped with a cooling fan is provided that can simplify the structure for attaching the fan cover and improve the ease of attachment. [Means for solving the problem]

[0005] The electric motor of the embodiment comprises an electric motor main body having motor brackets supporting a rotating shaft on both the front and rear sides of a cylindrical frame, a cooling fan provided on a portion of the rotating shaft protruding rearward from the rear motor bracket, and a cylindrical fan cover with an open front and provided on the rear of the motor main body to cover the cooling fan, the fan cover having an engagement hole located on the open end side and a convex engagement protrusion provided on the outer peripheral surface of the rear end of the frame or the outer peripheral surface of the rear motor bracket, the fan cover being attached by having the engagement hole engage with the engagement protrusion at three or more points in the circumferential direction so that the open end of the fan cover covers the outer peripheral surface of the rear end of the motor main body. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a vertical cross-sectional view of a main part showing a mounting structure of a fan cover according to a first embodiment. [Diagram 2] FIG. 1 is a cross-sectional view showing a schematic overall configuration of an electric motor; [Diagram 3] An enlarged perspective view of the rear portion of the electric motor body. [Figure 4] Rear view of the fan cover [Diagram 5] FIG. 11 is a vertical sectional side view of a main part of a fan cover according to a second embodiment. [Figure 6] Front view of the main part of the fan cover [Figure 7] FIG. 13 is a vertical cross-sectional view of a main part showing a mounting structure of a fan cover according to a third embodiment. [Figure 8] FIG. 13 is an enlarged perspective view of a rear portion of a motor body according to a fourth embodiment. [Figure 9] FIG. 11 is a perspective view showing a plurality of engagement protrusions having different shapes according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, several embodiments applied to electric motors for various industrial equipment will be described with reference to the drawings. Since the configuration of the electric motor body and the like is common among the embodiments, the same parts are given the same reference numerals and detailed explanations and new illustrations will be omitted. In addition, in the drawings, the axial direction of the electric motor, i.e., the direction in which the center line of the rotating shaft extends, is shown as the left-right direction, and in Figure 2, etc., the right side is the front side, which is the load side, and the left side is the rear side, which is the anti-load side.

[0008] (1) First embodiment A first embodiment will be described with reference to Fig. 1 to Fig. 4. First, Fig. 2 shows a schematic diagram of the overall configuration of a main body 1 of an electric motor according to this embodiment. Here, the main body 1 of the electric motor is configured to include a stator 3 and a rotor 4 in a metal frame 2 that is, for example, cylindrical as a whole. A rotating shaft 5 is fixed to the rotor 4. The stator 3 is configured by windings 3b wound around a stator core 3a, and is attached to the inner peripheral surface of the frame 2. The rotor 4 is, for example, a squirrel-cage rotor, and is disposed on the inner peripheral portion of the stator 3.

[0009] As only a portion of the fins is shown in Fig. 2, a plurality of heat dissipation fins 6 are provided, for example, integrally on the outer peripheral surface of the frame 2, extending in the axial direction, i.e., the front-rear direction. Metallic motor brackets 7, 8 are provided on both the front and rear ends of the frame 2. As shown in Fig. 2, bearings 9, 10 are attached to the motor brackets 7, 8, respectively. The rotating shaft 5 is supported for free rotation by the bearings 9, 10. As also shown in Fig. 1, the rear end of the rotating shaft 5 protrudes rearward from the motor bracket 8, and a cooling fan 11 is attached to the protruding end.

[0010] 1 and other figures, a fan cover 12 made of sheet metal is attached to the rear end of the motor body 1 so as to cover the cooling fan 11. As shown in Fig. 4, this fan cover 12 is substantially cylindrical with an open front, and has a number of ventilation holes 12a in its rear surface. This fan cover 12 is attached so that its front end opening covers the outer periphery of the rear end of the motor body 1. The attachment structure of this fan cover 12 will be described later.

[0011] Here, the joining structure between the frame 2 and the motor brackets 7, 8, particularly the joining structure with the rear motor bracket 8, will be described. As shown in Figures 1 to 3, rectangular block-shaped mounting seats 13 are integrally provided on the outer periphery of the motor bracket 8, positioned at, for example, three locations in the circumferential direction, so as to protrude in the outer periphery direction. These mounting seats 13 are formed with insertion holes 13a for bolts penetrating in the axial direction.

[0012] On the other hand, mounting seats 14 are integrally provided on the outer periphery of the rear end of the frame 2 at three circumferential positions corresponding to the mounting seats 13. These mounting seats 14 are provided in the shape of blocks that are slightly long in the axial direction and are located between the heat dissipation fins 6, and have screw holes 14a that open at the rear end face and extend in the axial direction. The motor bracket 8 is then positioned so that each mounting seat 13 is assigned to each mounting seat 14 of the frame 2, and a bolt 15 is fastened from the rear to the screw hole 14a through the insertion hole 13a. This joins the motor bracket 8 to the frame 2. The front motor bracket 7 is also joined in a similar joining structure that is symmetrical between the front and rear.

[0013] Now, the mounting structure of the fan cover 12 to the motor body 1 will be described. In this embodiment, as shown in Fig. 1 and Fig. 3, the fan cover 12 is provided with engagement holes 16 located on the open end side. These engagement holes 16 are provided at three locations in the circumferential direction, that is, at locations corresponding to the mounting seats 13. Meanwhile, a convex engagement protrusion 17 is provided integrally, for example, on the outer circumferential surface of the rear motor bracket 8, in this case, the outer circumferential surface of each mounting seat 13. In this case, as shown in Fig. 3, the engagement protrusion 17 is provided in a circular, i.e. cylindrical, shape.

[0014] 1 and 2, the open end of fan cover 12 covers the outer peripheral surface of the rear end of motor body 1, and engagement holes 16 provided in fan cover 12 engage with engagement protrusions 17 provided on the outer peripheral surface of rear motor bracket 8 at three points in the circumferential direction, thereby attaching fan cover 12 to motor body 1. Furthermore, for example during maintenance, fan cover 12 can be easily removed from motor body 1 by pulling engagement holes 16 of fan cover 12 out of engagement protrusions 17 of motor bracket 8.

[0015] According to the mounting structure of the fan cover 12 to the electric motor body 1 of this embodiment, the following actions and effects can be obtained. That is, in this embodiment, the fan cover 12 is mounted to the electric motor body 1 by engaging the engaging protrusions 17 provided on the outer circumferential surface of the rear motor bracket 8 with the engaging holes 16 provided in the fan cover 12 at three points in the circumferential direction.

[0016] In this case, unlike the conventional screw fastening, multiple screws are not required, and the number of parts is reduced. Moreover, no tools are required for screw fastening, and the number of steps is reduced compared to screw fastening, so that anyone can install the product with the same quality. Therefore, according to this embodiment, when used with a cooling fan 11, it is possible to obtain the excellent effects of simplifying the structure for installing the fan cover 12 and improving the ease of installation.

[0017] Particularly in this embodiment, the engaging protrusions 17 are provided on the outer periphery of the mounting seat 13 for joining the frame 2 and the motor bracket 8 with the bolts 15. As a result, the engaging protrusions 17 are provided on the mounting seat 13 which is originally provided, so that the engaging protrusions 17 can be provided easily. In addition, the overall radial dimension of the mounting seat 13 is not unnecessarily large. Furthermore, when installing the fan cover 12, the position of the engaging protrusions 17 can be easily identified by the worker.

[0018] In the conventional screw fastening structure, a screw hole extending in the diameter direction is formed on the outer circumferential surface of the mounting seat provided on the motor bracket or frame, which makes the mounting seat itself larger in the diameter direction. This causes the frame and fan cover themselves to become larger in the outer circumferential direction, and also creates large gaps around the mounting seat on the inner circumferential part of the fan cover and between the fins, which may allow a person's fingers to fit in. In contrast, in the configuration of this embodiment, no screw hole is required in the diameter direction in the mounting seats 13, 14, and the mounting seats 13, 14 themselves do not become very large in the radial direction, which makes it possible to reduce the size of the fan cover 12, reduce the gaps that allow a person's fingers to fit in, and ultimately improve safety.

[0019] (2) Second embodiment 5 and 6 show the main configuration of the fan cover 21 in the second embodiment, which differs from the first embodiment in the following configuration: The sheet metal fan cover 21 is generally cylindrical with an open front, and has engagement holes 22 at three circumferential locations on the open end side. As in the first embodiment, the open end of the fan cover 21 axially covers the outer circumferential surface of the rear end of the motor body 1, and the engagement holes 22 engage with engagement protrusions 17 provided on the outer circumferential surface of the rear motor bracket 8 at three circumferential locations, thereby attaching the fan cover 21 to the motor body 1.

[0020] In this embodiment, a guide groove 23 is provided on the inner circumferential surface of the fan cover 21, which extends linearly in the axial direction from the open end of the fan cover 21 to the engagement hole 22 and relatively guides the engagement protrusion 17. According to this configuration, when the fan cover 21 is attached to the electric motor body 1, the engagement protrusion 17 can be fitted in the axial direction while being aligned with the guide groove 23 of the fan cover 21.

[0021] Therefore, like the first embodiment, the second embodiment has the excellent effects of simplifying the structure for attaching the fan cover 12 and improving the ease of attachment in an apparatus equipped with the cooling fan 11. Furthermore, by providing the guide grooves 23 in the fan cover 21, it is possible to suppress circumferential positional deviation between the engagement holes 22 and the engagement protrusions 17 during the attachment of the fan cover 21, thereby further improving the ease of attachment.

[0022] (3) Third embodiment 7 shows a third embodiment, illustrating a mounting configuration of a fan cover 31 to an electric motor body 1. That is, in this embodiment, a rear motor bracket 32 ​​provided at the rear end of a frame 2 of the electric motor body 1 is provided integrally with mounting seats 33 located at multiple positions in the circumferential direction so as to be convex toward the outer periphery. The outer periphery of the mounting seats 33 is located so as to follow an imaginary circle corresponding to the inner periphery of the front end of the fan cover 31 as a whole. And, a first threaded portion 34 in the form of a male screw is provided on the outer periphery of the mounting seat 33 of the motor bracket 32, the first threaded portion 34 being centered on the central axis of the rotating shaft 5.

[0023] In contrast, the fan cover 31 is made of sheet metal and is formed into a generally cylindrical shape with an open front, and a second screw portion 35 in the form of a female screw is provided on the inner peripheral surface of the opening end, i.e., the front end, all around the circumferential direction. This allows the fan cover 31 to be attached and detached to the outer peripheral surface of the motor bracket 32 ​​at the rear end of the motor body 1 like a screw cap.

[0024] In the above configuration, the fan cover 31 can be attached to the rear of the motor body 1 by screwing the second threaded portion 35 of the fan cover 31 into the first threaded portion 34 on the outer circumferential surface of the rear motor bracket 32. The fan cover 31 can also be removed from the motor body 1 by unscrewing it.

[0025] In this case, unlike the case where screws are used, multiple screws are not required, and the number of parts is reduced. Moreover, no tools are required for screwing, and the number of steps is reduced compared to the case where screws are used, so that anyone can perform the installation with the same work quality. Therefore, according to the third embodiment, in a device equipped with the cooling fan 11, it is possible to obtain the excellent effects of simplifying the installation structure of the fan cover 31 and improving the installation workability. Although the first screw portion 34 is provided intermittently in the circumferential direction on the outer circumferential surface of the motor bracket 32, it may be configured to be provided all around the circumference.

[0026] (4) Fourth embodiment 8 shows the fourth embodiment, which differs from the first embodiment in the following respects: In the fourth embodiment, a mounting seat 42 for coupling is integrally provided on the outer periphery of the rear end of a frame 41 of an electric motor body 1, corresponding to the mounting seat 13 of the motor bracket 8. Although not shown, a threaded hole that opens at the rear end face and extends in the axial direction is formed in the mounting seat 42, and the motor bracket 8 is coupled to the frame 41 by fastening a bolt 15 through an insertion hole in the mounting seat 13 into the threaded hole in the mounting seat 42.

[0027] In this embodiment, a stopper 43 is integrally provided on the outer peripheral surface of the mounting seat 42, against which the tip of the fan cover 12 abuts to position the fan cover in the axial direction. According to the configuration of the fourth embodiment, the tip of the fan cover 12 abuts against the stopper 43 to position the fan cover in the axial direction. This makes it possible to prevent the fan cover 12 from going too far in the axial direction during the installation work and having to start over, making the installation work easier. It also has the effect of preventing the fan cover 21 from shifting in the axial direction after installation.

[0028] (5) Other embodiments 9 shows other embodiments, illustrating several examples of the shapes of the convex engagement protrusions provided on the outer peripheral surface of the rear end portion of the frame 2 or the outer peripheral surface of the rear motor bracket 8. In the above first embodiment, a cylindrical engagement protrusion 17 is provided, but various shapes can be used, such as a square engagement protrusion 51, a triangular engagement protrusion 52, a truncated cone engagement protrusion 53, and a mountain-shaped engagement protrusion 54. In the above first embodiment etc., the engagement protrusion 17 is provided on the rear motor bracket 8, but it may also be configured to be provided on the outer peripheral surface of the rear end portion of the frame 2.

[0029] In addition, in the above embodiment, the engagement projections and engagement holes are provided at three circumferential positions, but they may be provided at four or even five or more circumferential positions. The joining structure of the motor bracket to the frame can also be modified as appropriate, for example, by joining using bolts and nuts. The shape of the fan cover and the configuration of the ventilation holes can also be modified in various ways, and the frame of the motor main body can also be modified in various ways with respect to the shape and structure of the heat dissipation fins, and may not have heat dissipation fins.

[0030] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0031] In the drawings, 1 is a motor body, 2 and 41 are frames, 3 is a stator, 4 is a rotor, 5 is a rotating shaft, 6 is a heat dissipation fin, 7, 8 and 32 are motor brackets, 11 is a cooling fan, 12, 21 and 31 are fan covers, 13 and 33 are mounting seats, 14 and 42 are mounting seats, 16 and 22 are engagement holes, 17, 51, 52, 53 and 54 are engagement protrusions, 23 is a guide groove, 34 is a first screw portion, 35 is a second screw portion, and 43 is a stopper.

Claims

[Claim 1] an electric motor body having motor brackets supporting a rotating shaft on both the front and rear sides of a cylindrical frame; a cooling fan provided on a portion of the rotating shaft protruding rearward from the rear motor bracket; a fan cover having a cylindrical shape with an open front surface and provided at a rear portion of the motor body so as to cover the cooling fan, The fan cover is provided with an engagement hole located on an open end side, A convex engagement projection is provided on an outer circumferential surface of the rear motor bracket, The fan cover is attached by having an open end portion of the fan cover cover an outer peripheral surface of a rear end portion of the motor body, and the engagement holes are engaged with the engagement protrusions at three or more points in a circumferential direction, a guide groove is provided on an inner peripheral surface of the fan cover, the guide groove extending in an axial direction from an open end of the fan cover to the engagement hole and guiding the engagement projection relatively; an outer periphery of the rear motor bracket is provided with mounting seats at three or more locations in a circumferential direction for fastening the frame and the rear motor bracket with bolts, and the engagement projection is provided on an outer periphery of the mounting seats; a stopper is provided on an outer peripheral surface of a rear end portion of the frame to abut against a tip end of the fan cover for axial positioning, The stopper is provided on the outer peripheral surface of a joining mounting seat formed on the outer peripheral surface of the rear end portion of the frame at three or more locations in the circumferential direction corresponding to the mounting seat, and is formed in a rectangular block shape that is long in the circumferential direction. Electric motor.

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