Rotating electric machine

Abstract

The present invention provides a rotating electric machine that can efficiently cool itself with a simple configuration while suppressing the impact on sensors. [Solution] The rotating electric machine 1 according to this embodiment includes a cooling fan 8 attached to the shaft member 5 on the load side, a sensor 10 attached to the outside of the non-load side bracket 7, and a fan cover 11 that guides the airflow generated by the cooling fan 8 along the surface of the frame 2. The fan cover 11 is formed in a generally bottomed cylindrical shape, having a fan side wall portion 11a that extends axially at a position where a gap is formed between it and the surface of the frame 2, and a fan side bottom portion 11c provided at the end of the fan side wall portion 11a, with an insertion opening 11b formed in the center into which a cylindrical portion 6a is inserted. The fan side bottom portion 11c is mounted so that it is located on the load side of the exhaust port 6d.

Description

Technical Field

[0001] Embodiments of the present invention relate to a rotating electric machine provided with a sensor.

Background Art

[0002] In the case of a rotating electric machine with a large load and a large amount of heat generation, it is necessary to increase the core diameter or increase the stack thickness of the stator for heat countermeasures. However, when connecting the rotating electric machine and the load, there may be restrictions on dimensions and weight. Therefore, for example, in Patent Document 1, a configuration may be adopted in which a cooling fan and a fan cover are provided in the rotating electric machine for cooling.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when a sensor such as an encoder is provided in a rotating electric machine, if the misalignment of the axis increases, the signal from the sensor will be disturbed, and there is a risk of false detection such as the rotating electric machine vibrating or an error in the detected value itself. Therefore, conventionally, a robust fan cover and a counter-load side bracket are used, or a so-called in-roll type fitting structure is adopted to achieve robustness and prevention of axis misalignment. However, in that case, it will lead to a complication of the structure and an increase in weight, and there is a risk of being subject to the above-mentioned restrictions.

[0005] Therefore, a rotating electric machine is provided that can efficiently cool the rotating electric machine with a simple configuration while suppressing the influence on the sensor.

Means for Solving the Problems

[0006] The rotating electric machine according to this embodiment includes a hollow frame, a stator positioned on the inner circumference of the frame, a rotor positioned on the inner circumference of the stator, a shaft member fixed to the center of the rotor, a load-side bracket that closes the end of the frame on the load-side, which is one end in the axial direction, a cooling fan attached to the shaft member on the outside of the frame on the load-side, a non-load-side bracket that closes the end of the frame on the non-load-side, which is the other end in the axial direction, a sensor attached to the outside of the non-load-side bracket on the non-load-side, and a fan cover that guides the airflow generated by the cooling fan along the surface of the frame. The load-side bracket extends beyond the cooling fan to the load side in a manner that surrounds the outer circumference of the cooling fan, and has a cylindrical portion with an exhaust port for discharging air provided on its wall surface. The fan cover is formed in a bottomed cylindrical shape, having a fan side wall portion that extends axially at a position where a gap is formed between it and the surface of the frame, and at least a portion of which overlaps with the load-side bracket in the axial direction, and a fan side bottom portion that rises radially inward from the load-side end of the fan side wall portion and has an insertion opening in the center into which a cylindrical portion is inserted, and is installed with the fan side bottom portion positioned on the load side of the exhaust port. [Brief explanation of the drawing]

[0007] [Figure 1] A schematic diagram showing an example of the configuration of a rotating electric machine according to an embodiment. [Figure 2] A schematic diagram showing an example of a fan cover configuration. [Figure 3] A schematic diagram showing other examples of fan cover configurations. [Figure 4] A schematic diagram showing the state with the air guide cover installed. [Figure 5] A schematic diagram showing an example of the configuration of an air guide cover. [Modes for carrying out the invention]

[0008] The embodiments will be described below with reference to the drawings. As shown in Figure 1(a) as a side view with a portion broken off, the rotating electric machine 1 according to this embodiment comprises a hollow frame 2, a stator 3 arranged on the inner circumference side of the frame 2, a rotor 4 arranged on the inner circumference side of the stator 3, and a shaft member 5 fixed to the center of the rotor 4. Hereinafter, the left-right direction shown along the rotation axis (J) will be referred to as the axial direction, the right side shown, which is one end to which a load is connected to the shaft member 5 in the axial direction, will be referred to as the load side, and the opposite end, the left side shown, will be referred to as the non-load side.

[0009] Frame 2 is formed in a cylindrical shape with both axial ends open and fins 2a extending axially from its outer circumference, and a stator 3 is fixed to its inner circumference. Furthermore, the load-side end of frame 2 is closed by a load-side bracket 6, except for the shaft member 5, and the non-load-side end is closed by a non-load-side bracket 7, except for the shaft member 5. In other words, the rotating electric machine 1 has a so-called fully enclosed structure in which the inside of frame 2 is sealed. These load-side bracket 6 and non-load-side bracket 7 are structurally robust in order to support the shaft member 5, and are firmly fixed to frame 2 with a highly precise positional relationship to the shaft member 5.

[0010] Furthermore, the rotating electric machine 1 is equipped with a cooling fan 8 attached to the shaft member 5 at the inner circumference of the cylindrical portion 6a of the load-side bracket 6, at a position outside the frame 2. The cylindrical portion 6a rises from near the outer edge of the load-side closing plate 6b that closes the opening of the frame 2 toward the load side, surrounding the outer circumference of the cooling fan 8, and extends beyond the cooling fan 8 toward the load side, with the load-side end formed in an open shape. In addition, the cylindrical portion 6a is provided with a flange structure 6c near the load-side end for attachment to a structure (X) such as a load or a surrounding structure of the load.

[0011] Furthermore, as shown in Figure 1(c), which illustrates a simplified structure viewed from the direction of line c, the cylindrical portion 6a is provided with exhaust ports 6d for discharging air from the inside of the cylindrical portion 6a. In this embodiment, multiple exhaust ports 6d are provided, with at least a portion of them overlapping with the cooling fan 8 in the axial direction.

[0012] Inside the cylindrical portion 6a, as shown in Figure 1(b) viewed from the direction of line b, there is a mesh-like structure with multiple openings that allows air to be taken in, and a protective cover 9 is provided to prevent contact with the cooling fan 8. The cylindrical portion 6a is also provided with air intake ports 6e for taking air into the interior of the cylindrical portion 6a. In this embodiment, multiple air intake ports 6e are provided, with at least a portion of them axially aligned with the cooling fan 8.

[0013] Therefore, as will be described later, when the cooling fan 8 rotates, air is drawn in from the intake port 6e or the protective cover 9 to the inner circumference of the cylindrical part 6a, and the air is discharged from the exhaust port 6d to the outside of the cylindrical part 6a. Note that the number and arrangement of the exhaust port 6d and intake port 6e, or the configuration of the protective cover 9, are examples only and are not limited thereto.

[0014] Furthermore, the rotating electric machine 1 is equipped with a sensor 10 mounted on the outside of the non-load side bracket 7. In this embodiment, the sensor 10 is assumed to be an encoder that detects the rotational speed, rotational direction, or rotational position of the rotating electric machine 1. The sensor 10 has a main body portion 10a (see Figure 5) fixed to the surface of the non-load side bracket 7, and a shaft member 5 is connected to a detection portion 10b (see Figure 5) provided in the center of the sensor. Note that the type and structure of the sensor 10 are examples only and are not limited thereto.

[0015] When a sensor 10 is installed on a rotating electric machine 1, if there is a large misalignment between the rotation axis (J) and the center of the sensor 10, it may affect the detection signal of the sensor 10, potentially causing vibration and detection errors. Therefore, when installing the sensor 10, it is important that the mounting area for the sensor 10 is robust and that there is no misalignment of the axis. However, pursuing robustness may lead to a more complex mounting structure, increased weight, and larger dimensions, which may impose limitations on the installation of the rotating electric machine 1.

[0016] Therefore, in this embodiment, in order to cool the rotating electric machine 1 with a simple configuration while suppressing the influence on the sensor 10, a fan cover 11 is provided to guide the airflow generated by the cooling fan 8 along the surface of the frame 2. As shown in Figure 2(a), the fan cover 11 extends axially with a gap between it and the surface of the frame 2 and is formed in a generally bottomed cylindrical shape, having a fan side wall portion 11a in which at least a part of it overlaps with the load-side bracket 6 in the axial direction, and a fan-side bottom portion 11c that rises radially inward from the load-side end of the fan side wall portion 11a and has an insertion opening 11b in its center into which a cylindrical portion 6a is inserted.

[0017] The fan cover 11 is designed to guide air, and therefore only needs to be strong enough to maintain its shape, resulting in a thin and lightweight structure. The fan cover 11 is provided with multiple screw holes 11d for fixing at the non-load end of the fan side wall portion 11a. The fan cover 11 is installed with a gap between it and the surface of the frame 2, as shown in Figure 2(b), and with the fan side bottom portion 11c positioned on the load side of the exhaust port 6d, as shown in Figures 1(a) and (c). In this embodiment, the fan side wall portion 11a of the fan cover 11 is screwed to the outer circumferential surface of the load side fixing portion 6f that fixes the frame 2 and the load side bracket 6. However, the method of fixing the load side bracket 6 is not limited to this.

[0018] When the cooling fan 8 rotates as the shaft member 5 rotates, air is taken into the inside of the cylindrical portion 6a as shown by arrow F1 or F2 in FIG. 1, and after the air is discharged from the cylindrical portion 6a as shown by arrow F3, the direction is changed by the fan-side side wall portion and guided along the surface of the frame 2 to the anti-load side as shown by arrow F4. At this time, since the intake port 6e is provided in the cylindrical portion 6a, for example, even when the rotating electrical machine 1 is attached to the structure (X) and the opening of the cylindrical portion 6a is blocked, or when the distance between the cylindrical portion 6a and the structure portion (X) is close and it is difficult to take in air from the opening, it is possible to cool the rotating electrical machine 1.

[0019] According to the embodiment described above, the following effects can be obtained. The rotating electrical machine 1 according to the embodiment includes a hollow frame 2, a stator 3 disposed on the inner peripheral side of the frame 2, a rotor 4 disposed on the inner peripheral side of the stator 3, a shaft member 5 fixed to the center of the rotor 4, a load-side bracket 6 that closes the end of the frame 2 on the load side which is one end side in the axial direction, a cooling fan 8 attached to the shaft member 5 outside the frame 2 on the load side, an anti-load-side bracket 7 that closes the end of the frame 2 on the anti-load side which is the other end side in the axial direction, a sensor 10 attached outside the anti-load-side bracket 7 on the anti-load side, and a fan cover 11 that guides the air flow generated by the cooling fan 8 along the surface of the frame 2.

[0020] The load-side bracket 6 extends to the load side beyond the cooling fan 8 in a manner surrounding the outer peripheral side of the cooling fan 8, and has a cylindrical portion 6a provided with an exhaust port 6d for discharging air on the wall surface. Further, the fan cover 11 extends along the axial direction at a position where a gap is formed between the fan cover 11 and the surface of the frame 2, and has a fan side wall portion 11a that at least partially overlaps the load-side bracket 6 in the axial direction, and a fan side bottom portion 11c that rises radially inward from the load-side end of the fan side wall portion 11a and has an insertion opening 11b into which the cylindrical portion 6a is inserted at the center. The fan cover 11 is generally formed in a bottomed cylindrical shape, and the fan side bottom portion 11c is attached in a state positioned on the load side of the exhaust port 6d.

[0021] By providing the fan cover 11 having a relatively simple shape, such as a generally bottomed cylindrical shape, it becomes possible to form an air flow on the load side where the influence on the sensor 10 is small and guide it to flow along the surface of the rotating electric machine 1, thereby improving the cooling efficiency of the rotating electric machine 1. At this time, since the fan cover 11 only needs to be able to change the direction of air flow, it can be thinned and lightened, and the influence on restrictions such as weight during installation can be minimized. Therefore, the rotating electric machine 1 can be cooled with a simple configuration while suppressing the influence on the sensor 10.

[0022] The sensor 10 is attached to the surface of the non-load-side bracket 7 having a robust structure and whose positional relationship with the shaft member 5 is also accurately defined. As a result, even without providing a structure for fixing the sensor 10, the sensor 10 can be firmly and reliably attached with high positional accuracy with respect to the shaft member 5, and it is possible to suppress false detection and a decrease in detection accuracy. Further, since the attachment accuracy of the sensor 10 is high, it can be expected that even a relatively inexpensive sensor 10 with relatively low detection accuracy can ensure the necessary detection accuracy, and cost reduction can also be achieved.

[0023] Furthermore, since the rotating electric machine 1 of this embodiment has a plurality of fins 2a provided along the axial direction on the surface of the frame 2, the fins 2a can also guide air along the axial direction, thereby further improving the cooling efficiency.

[0024] Furthermore, the cylindrical portion 6a has an air intake port 6e formed on the wall side facing the load rather than the exhaust port 6d to draw in air. This allows the rotating electric machine 1 to be cooled even if a structure (X) is placed near the opening of the cylindrical portion 6a, obstructing the intake of air from the opening.

[0025] Furthermore, the cylindrical portion 6a is provided with a flange structure 6c at the load-side end for fixing to the load or the surrounding structure of the load. This allows the rotating electric machine 1 to be directly attached to the structure (X). In this case, even if the opening is blocked by the structure (X), air can still be taken in through the air intake port 6e, thus preventing a decrease in cooling efficiency.

[0026] Incidentally, as shown in Figure 1, the diameter (L1) of the cylindrical portion 6a of the load-side bracket 6 is assumed to be smaller than the outer diameter (L2) of the flange structure 6c and the outer diameter (L3) of the fan-side bottom portion 11c. In that case, when attempting to insert the cylindrical portion 6a into the fan cover 11, the insertion opening 11b must be set larger than L2 or L3, which may result in a larger gap between the insertion opening 11b and the cylindrical portion 6a, causing air to leak and potentially reducing cooling efficiency.

[0027] Therefore, as shown in Figure 3(a), for example, the fan cover 11A can be made into a structure that can be divided into, for example, three equal parts in the circumferential direction, and each divided piece 12a to 12c can be attached to the rotating electric machine 1 to form a fan cover 11 that is ultimately roughly in the shape of a bottomed cylinder. In this case, by fixing the ends of each divided piece 12 with, for example, a plate-shaped connecting member 13 by screwing it in, each divided piece 12 can be connected and the outflow of air to the outside can be suppressed.

[0028] This prevents the gap between the fan-side bottom 11c and the cylindrical part 6a from becoming excessively wide, reducing air leakage and preventing a decrease in the amount of air flowing over the surface of the rotating electric machine 1, thus suppressing a decrease in cooling efficiency. Although Figure 3(a) shows an example of a shape divided into three equal parts in the circumferential direction, it is also possible to divide it into two or four equal parts in the circumferential direction, divide it in a way that is not equal in the circumferential direction, or have the ends of adjacent divided pieces 12 partially overlap in the circumferential direction.

[0029] Alternatively, as shown in Figure 3(b), the fan cover 11B can be made fan-shaped, with a discontinuous portion in the circumferential direction, covering at least a portion of the circumferential surface of the frame 2. In this case, by making the distance between the discontinuous portions (L4) larger than the diameter (L1) of the cylindrical portion 6a, the fan cover 11B can be attached by covering the cylindrical portion 6a. Such a shape can also be applied to structures where, for example, a mounting base 2b is provided below the frame 2, obstructing the axial airflow. In this case, by concentrating the exhaust ports 6d in the area covered by the fan cover 11B, air can be directed intensively along the surface of the frame 2.

[0030] By making the fan cover 11 divisible in the circumferential direction or discontinuous in a part of the circumferential direction, it becomes possible to easily attach it to the cylindrical part 6a, improving manufacturing efficiency, and also improving maintainability by making replacement easier in the event of damage.

[0031] Furthermore, if the flange structure 6c is not provided, the cylindrical fan cover 11 shown in Figure 2 can be easily attached and detached. Also, if the cylindrical portion 6a alone does not support the attachment to the structure (X), the cylindrical fan cover 11 shown in Figure 2 can be easily attached and detached by, for example, making the fan-side bottom portion 11c and the cylindrical portion 6a separable, and attaching the cylindrical portion 6a to the fan-side bottom portion 11c with the cylindrical portion 6a inserted into the insertion opening 11b.

[0032] So far, we have described an example configuration for cooling the rotating electric machine 1, but depending on the installation environment, there may be a need to cool the sensor 10 as well. In that case, if a cooling fan 8 or a dedicated fan is installed near the sensor 10, a mounting structure will be required, which may complicate the structure, or it may be subject to limitations in terms of weight and dimensions, or it may affect the sensor 10.

[0033] Therefore, in this embodiment, as shown in Figure 4, a guide cover 14 is provided on the rotating electric machine 1 to guide the air that has flowed along the surface of the frame 2 toward the sensor 10. As shown in Figures 5(a) and (b), the guide cover 14 is formed in a generally bottomed cylindrical shape and has a guide side wall portion 14a that extends axially at a position where a gap is formed between it and the surface of the frame 2 and covers the non-load side bracket 7 in at least a part in the circumferential direction, and a guide side bottom portion 14c that is provided in a manner that closes the non-load side end of the guide side wall portion 14a and has a guide side opening 14b formed in the center for discharging air.

[0034] As shown in Figure 4, the air guide cover 14 is attached to the outer circumferential surface of the non-load side fixing portion 7a for fixing the non-load side bracket 7 to the frame 2, with the air guide side wall portion 14a overlapping with at least a part of the non-load side bracket 7 in the axial direction. At this time, the air guide cover 14 is attached such that the air guide side bottom portion 14c is located on the load side of the end portion 10a of the main body portion 10a of the sensor 10 in the axial direction. Therefore, the axial dimension of the rotating electric machine 1 does not become longer than when the air guide cover 14 is not installed. Also, since the air guide cover 14 is for guiding air, it only needs to have enough strength to maintain its shape, and has a thin and lightweight structure.

[0035] By providing this air guide cover 14, the air flowing along the surface of the frame 2 is guided into the air guide cover 14 through the gap between the air guide side wall 14a and the surface of the frame 2, as indicated by arrow F5, and further guided toward the sensor 10 by the air guide side bottom 14c, as indicated by arrow F6, to cool the sensor 10. The air that has cooled the sensor 10 is then discharged to the outside through the air guide side opening 14b, as indicated by arrow F7.

[0036] By providing the air guide cover 14, which has a relatively simple shape, generally that of a bottomed cylindrical shape, it becomes possible to efficiently guide the air flowing along the surface of the rotating electric machine 1 to the sensor 10. Furthermore, it becomes possible to make the air guide cover 14 thinner and lighter, minimizing the impact on weight and other limitations during installation. In addition, the air guide cover 14 does not affect the cooling efficiency of the rotating electric machine 1 itself. Therefore, efficient cooling of both the rotating electric machine 1 and the sensor 10 can be achieved with a simple configuration.

[0037] Furthermore, since the air guide cover 14 has no movable parts, it does not generate vibrations or the like, and even when fixed to the non-load side flange, it can suppress the influence on the sensor 10. Although not shown in the figures, the air guide cover 14 can also be divided in the circumferential direction, as shown in the fan cover 11 in Figure 3, or it can be shaped to cover at least a part of the frame 2 in the circumferential direction.

[0038] In this embodiment, an example configuration is shown in which the fan cover 11 is fixed to the fan side wall portion 11a. However, a packing can be provided between the insertion opening 11b and the surface of the cylindrical portion 6a to suppress air leakage and contact with the cylindrical portion 6a due to vibration, etc. Alternatively, protrusions or screw holes can be provided on the outer circumferential surface of the cylindrical portion 6a to fix the outer circumferential surface of the cylindrical portion 6a to the fan side bottom portion 11c.

[0039] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of symbols]

[0040] In the drawing, 1 is the rotating electric machine, 2 is the frame, 3 is the stator, 4 is the rotor, 5 is the shaft member, 6 is the load-side bracket, 6a is the cylindrical part, 6c is the flange structure, 6d is the exhaust port, 6e is the intake port, 7 is the non-load-side bracket, 8 is the cooling fan, 10 is the sensor, 11, 11A, and 11B are the fan cover, 11a is the fan side wall, 11b is the insertion opening, 11c is the fan-side bottom, 14 is the air guide cover, 14a is the air guide side wall, 14b is the air guide opening, and 14c is the air guide-side bottom.

Claims

1. A hollow frame, A stator positioned on the inner circumference side of the frame, The rotor is located on the inner circumference side of the stator, A shaft member fixed to the center of the rotor, A load-side bracket that closes the end of the frame on the load-side, which is one end in the axial direction, A cooling fan is attached to the shaft member on the outside of the frame on the load side, A non-load side bracket that closes the end of the frame on the non-load side, which is the other end in the axial direction, A sensor mounted on the outside of the non-load side bracket on the non-load side, The system includes a fan cover that guides the airflow generated by the cooling fan along the surface of the frame, The load-side bracket extends beyond the cooling fan to the load side, surrounding the outer circumference of the cooling fan, and has a cylindrical portion with an exhaust port for discharging air provided on its wall surface. The fan cover is formed in a bottomed cylindrical shape, having a fan side wall portion that extends axially at a position where a gap is formed between it and the surface of the frame, and at least a portion of which overlaps with the load-side bracket in the axial direction, and a fan side bottom portion that rises radially inward from the load-side end of the fan side wall portion, with an insertion opening formed in the center into which the cylindrical portion is inserted, and is mounted such that the fan side bottom portion is located on the load side of the exhaust port.

2. The rotating electric machine according to claim 1, wherein the cylindrical portion has an air intake port formed on the wall surface on the load side of the exhaust port for taking in air.

3. The rotating electric machine according to claim 1, wherein the cylindrical portion is provided with a flange structure at the load-side end for fixing to a load or a surrounding structure of the load.

4. The system includes an air guide cover that directs the air guided by the fan cover and flowing along the surface of the frame toward the sensor, The rotating electric machine according to claim 1, wherein the air guide cover is formed in a bottomed cylindrical shape having an air guide side wall portion that extends axially at a position where a gap is formed between it and the surface of the frame and covers the non-load side bracket in the circumferential direction in at least a portion thereof, and an air guide side bottom portion that is provided in a manner that closes the non-load side end of the air guide side wall portion and has an air guide side opening formed in the center for discharging air, and the air guide side wall portion is attached in a manner that overlaps with at least a portion of the non-load side bracket in the axial direction.

Images