Fan-cooled closed-type motor improved by symmetrization

Abstract

To provide a fan-cooling close-type motor improved by symmetry.SOLUTION: A motor includes: a shaft defining a longitudinal axis of the motor; a rotor integral with a stator formed integrally with axial walls forming a frame of a motor, and the shaft, in a closed volume part defined axially by first and second transverse partitions and radially by the axial walls; and a first flow path system outside the closed volume part and on or through the axial wall and a first fan mounted on the outside of the first transverse partition and mounted on the shaft for circulating air in the flow path system to cool the stator. The motor further includes a second flow pass system on or through the surface of the axial wall and a second fan mounted on the outside of the second transverse partition and mounted on the shaft for circulating air in the second flow path system to cool the stator outside the closed volume part.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a fan-cooled closed-type motor of a type including a shaft defining the longitudinal axis of a motor, a stator integral with an axial wall and a rotor integral with the shaft, the stator being in a closed volume defined axially by a first transverse partition wall and a second transverse partition wall and radially by the axial walls constituting the frame of the motor, a flow path system passing through the surface or inside of the axial wall outside the closed volume, and a fan provided outside the first transverse partition wall, the fan being attached to the shaft and circulating cooling air in the flow path system to cool the stator.

Background Art

[0002] Patent Document 1 discloses a closed-type motor cooled by a fan of the above type.

[0003] However, the cooling means of this prior art motor composed of a fan and a flow path system causes a large temperature gradient in the axial direction through the motor, especially through the stator. In fact, the cold air sent into the flow path by the fan gradually increases in temperature as it moves through the flow path while collecting the heat of the stator. As a result, the air reduces its cooling efficiency as it moves. Therefore, the part of the stator close to the fan is better cooled than the part of the stator far from the fan. Thus, a temperature gradient occurs through the stator. This is not good for the optimal operation of the motor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The objective of this invention is to resolve this problem. [Means for solving the problem]

[0006] Therefore, the present invention relates to a motor of the type described above, wherein the fan and flow path system is a first fan and a first flow path system, and further comprises outside the enclosed volume a second flow path system passing through the surface or interior of the axial wall, and a second fan provided outside the second transverse partition wall and mounted on the shaft to circulate cooling air to the second flow path system to cool the stator.

[0007] According to some specific embodiments, the motor is equipped with one or more of the following features, either individually or in any technically possible combination. - The first transverse partition wall and the second transverse partition wall are each composed of a first flange and a second flange that constitute the motor frame, and the flanges are integral with the axial wall and connected to the shaft via bearings. - The first transverse partition wall and the second transverse partition wall are each composed of a first fan and a second fan, respectively. - The motor further comprises a first flange and a second flange, one flange being integral with the axial wall and connected to the shaft via a bearing, and the other flange being located further away from the fan with respect to the enclosed volume and having an opening to allow air to be drawn in by the fan. - The first and second fans are made of aluminum. - The flow paths of the first and second flow path systems proceed axially along the axial wall. - The channels of the first channel system and the channels of the second channel system are spaced regularly in an annular pattern by the axial wall, with each channel of the first channel system sandwiched between two channels of the second channel system. - When N is the number of channels in each channel system, the two channel systems are angled relative to each other by an angle equal to π / N in the cross-section with respect to the longitudinal axis A. - The channels of the first and second channel systems pass through the stator. - The motor is symmetrical with respect to the central plane in the transverse direction with respect to the motor's axis.

[0008] The present invention and its advantages will be better understood by reading the following detailed description of specific embodiments, which are provided only as non-limiting examples, with reference to the accompanying drawings. [Brief explanation of the drawing]

[0009] [Figure 1] These are two axial half-cross-sectional views of a motor according to a first embodiment of the present invention. [Figure 2] These are two axial half-cross-sectional views of a motor according to a second embodiment of the present invention. [Figure 3] Figure 1 and Figure 2 are cross-sectional views of the motor at its center plane. [Modes for carrying out the invention]

[0010] A first embodiment of the fan-cooled closed-type motor according to the present invention will be described with reference to Figure 1.

[0011] Motor 102 is an electric motor suitable for converting electrical output into mechanical output.

[0012] The motor includes a shaft 104 extending along the longitudinal axis A. The shaft is a through shaft. In a modified example, it may be a half shaft.

[0013] Axis A is the axis of rotation for the rotating parts of motor 102.

[0014] The motor 102 comprises a fixed stator 106 and a rotor 108 that is integrated with the shaft 104.

[0015] The motor 102 is equipped with a frame 110.

[0016] The frame 110 consists of an axial wall, a first flange 114 and a second flange 115.

[0017] The axial wall is substantially cylindrical around the axis A. In the embodiment of FIG. 1, the axial wall is constituted by a stator 106 attached between a first end portion 112 of the axial wall and a second end portion 112' of the axial wall.

[0018] In a modified example, the stator is fixed to the inner surface of the central portion of the axial wall.

[0019] The first flange 114 and the second flange 115 arranged in a transverse direction with respect to the axis A close the respective open ends of the first end portion 112 of the axial wall and the second end portion 112' of the axial wall.

[0020] The frame 110 is fixed. The frame is connected to the shaft 104 by bearings, that is, between the first flange 114 and the shaft 104 by a first bearing 116, and between the second flange 115 and the shaft 104 by a second bearing 117, respectively.

[0021] The motor 102 is of a closed type, that is, the rotor-stator assembly is located within a closed volume 118.

[0022] In the embodiment of FIG. 1, the closed volume 118 is defined radially by the axial wall and longitudinally by the first flange 114 and the second flange 115. Therefore, the first flange and the second flange are closed.

[0023] A fluid, which is air or any other gas confined within the closed volume 118, is heated by the magnetic loss of the rotor-stator assembly.

[0024] Advantageously, a passage 109 is provided through the rotor 108 to allow a certain degree of air circulation within the closed volume section 118. This allows air to flow through the passage 109 and the air gap 107 between the stator 106 and the rotor 108. In Figure 1, this flow is indicated by arrow F3.

[0025] To cool the stator 106, the motor 102 is equipped with a cooling means outside the enclosed volume section 118, which includes a first cooling means on the first axial side of the motor and a second cooling means on the second axial side of the motor.

[0026] The first cooling means comprises a first fan 122 integrated with the shaft 104, and in this first embodiment, the first fan 122 is located outside the frame 110. More specifically, the first fan 122 is located outside the first flange 114 with respect to the enclosed volume section 118.

[0027] The first cooling means includes a first flow path system 124 provided within the thickness of the axial wall, in conjunction with the first fan 122.

[0028] The first flow path system 124 comprises multiple N flow paths 124-i (Figure 3), where the subscript i is an integer from 1 to N. For example, N is 4. In modified examples, a different number of flow paths may be used.

[0029] The flow path comprises, in order, an inlet section 126 that is bent in the axial plane, and a main section 128 that is almost straight and arranged parallel to axis A. The open proximal end of the inlet section 126 is fluidly connected to the first fan 122. The open distal end of the main section 128 is advantageously fluidly connected to means for forming a scoop (ecope) so that hot air is discharged away from the motor.

[0030] The first cooling means, located to the left of the motor 102 in Figure 1, enables airflow along the arrow F1, which flows from left to right in Figure 1 and towards the front of the surface in Figure 3.

[0031] As the first fan 122 rotates on the shaft 104, cool air from outside the motor 102 is drawn in, and this drawn-in air is sent to the inlet 126 of each flow path 124-i of the first system 124. The introduced air then flows through the main section 128 of each flow path 124-i of the first system 124, cooling the stator 106. As the air moves axially along the stator 106, it absorbs heat from the stator and its temperature rises. Finally, the hot air is discharged into the environment, advantageously away from the motor 102.

[0032] The second cooling means is a second fan 123 integrated with the shaft 104 symmetrically with respect to the central plane M of the motor 102, and in this first embodiment, the second fan is located outside the frame 110. More specifically, the second fan 123 is located outside the second flange 115 with respect to the enclosed volume 118.

[0033] The second cooling means includes a second flow path system 125 provided within the thickness of the axial wall, in conjunction with the second fan 123.

[0034] The second flow path system 125 comprises multiple N flow paths 125-i (Figure 3), where the subscript i is an integer from 1 to N. For example, N is 4. The number of flow paths in the second system 125 is preferably the same as the number of flow paths in the first system 124, but it may be different.

[0035] The flow path comprises, in order, an inlet section 127 that is bent in the axial plane, and a main section 129 that is almost straight and arranged parallel to axis A. The open proximal end of the inlet section 127 is fluidly connected to a second fan 123. The open distal end of the main section 129 is advantageously fluidly connected to means for forming a scoop.

[0036] The second cooling means, located to the right of the motor 102 in Figure 1, enables airflow along arrow F2, which flows from right to left in Figure 1 and towards the back of the surface in Figure 3.

[0037] As the second fan 123 rotates on the shaft 104, cool air from outside the motor 102 is drawn in, and this drawn-in air is then sent to the inlet 127 of each flow path 125-i of the second system 125. The introduced air then flows through the main section 129 of each flow path 125-i of the second system 125, cooling the stator 106. As the air moves axially along the stator 106, it absorbs heat from the stator and its temperature rises. Finally, the hot air is discharged into the environment, advantageously away from the motor 102.

[0038] In this way, by symmetrizing with respect to the transverse central plane M, two flows of the cooling fluid, F1 and F2, are created, which pass through the stator 206 longitudinally and flow in opposite directions. This reduces the temperature gradient between the longitudinal ends of the stator 106. As a result, the temperature of the stator becomes more homogeneous, and the cooling of the stator 106 is improved.

[0039] Figure 3 is a cross-sectional view of the motor 102 at its center plane M, showing the relative positions and layout of the flow paths 124-1, 124-2, 124-3, 124-4, and 125-1, 125-2, 125-3, 125-4 of the first flow path system 124 and the second flow path system 125, respectively.

[0040] The first flow path system 124 and the second flow path system are independent of each other.

[0041] To standardize the components of the motor 102 and facilitate assembly, the first system 124 and the second system 125 are identical but are arranged on the frame 110 at an angle to each other around axis A. Since there are four flow paths in each system, the second system 125 is rotated by an angle a equal to 45° relative to the first system 124. This is why Figure 1 shows two half-sections along the axial plane on both sides of the central plane M; the half-section corresponding to the right part of the motor becomes the axial plane of the half-section corresponding to the left part of the motor when pivoted 45° around axis A. In other words, the symmetrical shape of the external cooling means can be understood from the offset between the first external cooling means and the second external cooling means.

[0042] For example, in this first embodiment, the stator 106 is a laminated stator made up of stacked identical thin plates.

[0043] As shown in Figure 3, each thin plate 109 is inscribed within a single circle.

[0044] Each thin plate 109 has a notch on its outer side such that the laminate, which is formed by the successive overlapping of the thin plates in the axial direction, forms a longitudinal recess that receives the coil.

[0045] Each thin sheet 109 has a plurality of ventilation ports near its periphery, preferably between two consecutive notches. Each thin sheet 109 has 2 × N ventilation ports uniformly distributed in an annular shape. Two consecutive ports are offset by an angle a.

[0046] The laminate obtained by stacking thin plates one after another in the axial direction forms multiple channels in the longitudinal direction. Each port of the thin plate corresponds to the cross-section of an individual channel in the channel system. Even-numbered ports form channel 125-i of the second channel system 125, and odd-numbered ports define channel 124-i of the first channel system 124.

[0047] The first end portion 112 and the second end portion 112' of the axial wall each have N holes, each of which connects to one hole for every two flow channels in the laminate of thin plates. The holes in the first portion 112 connect to, for example, odd-numbered ports of the thin plates, and the holes in the second portion 112' connect to even-numbered ports of the thin plates.

[0048] Therefore, the first portion 112 and the second portion 112' of the axial wall, which are preferably the same, are rotated by an angle a between them in order to direct the airflow toward the odd-numbered channel 124 or the even-numbered channel 125.

[0049] In this embodiment, each flow path extends longitudinally. In a variation, the flow paths could also flow within or on the surface of the motor frame in a different manner. For example, each flow path could be shaped like a helical curve.

[0050] Those skilled in the art will know how to adapt the shape and assembly of thin plates to construct a flow path system with a different number of flow paths and / or flow paths of different shapes.

[0051] In a modified example, the stator is fixed to the inner surface of the central portion of the axial wall, and the central portion is machined to have a flow path for the flow system within its thickness.

[0052] Advantageously, the axial wall is created by assembling two appropriately machined half-shells such that a flow channel is formed when assembled. Advantageously, these two half-shells are identical.

[0053] In yet another variation, the fluid flow system is added to the motor frame.

[0054] Figure 2 shows a second embodiment of the motor according to the present invention. Elements of the second embodiment that are identical or similar to corresponding elements of the first embodiment are referred to by a reference numeral 100 added to the numeral used to refer to the corresponding element.

[0055] The motor 202 includes a shaft 204 mounted to rotate around axis A.

[0056] The motor 202 comprises a fixed stator 206 and a rotor 208 integrated with the shaft 204.

[0057] The motor 202 includes a frame 210 comprising an axial wall (obtained by assembling a first end portion 212, a stator, and a second end portion 212'), a first flange 214, and a second flange 215.

[0058] The frame 210 is fixed. The frame 210 is connected to the shaft 204 by bearings, specifically, the first flange 214 and the shaft 204 are connected by the first bearing 216, and the second flange 215 and the shaft 204 are connected by the second bearing 217.

[0059] The motor 202 is of the enclosed type; that is, the rotor-stator assembly is located within a closed volume 218 inside the frame 210.

[0060] To cool the stator 206, the motor 202 is equipped with a cooling system outside the enclosed volume section 218, which includes a first cooling system on the first axial side of the motor and a second cooling system on the second axial side of the motor opposite to the first side.

[0061] The first cooling means is a first fan 222 integrated with the shaft 204, and in this second embodiment, the first fan 222 is located inside the frame 210. More specifically, the first fan 222 is located inside the first flange 214 with respect to the enclosed volume 218.

[0062] The first cooling means includes a first flow path system 224 provided within the thickness of the axial wall, in conjunction with the first fan 222.

[0063] The first flow path system 224 comprises multiple N flow paths 224-i (Figure 3).

[0064] The flow path preferably comprises, in order, a bent inlet 226 and a main section 228 which is preferably substantially straight and arranged parallel to axis A. The open proximal end of the inlet 226 is fluidly connected to the first fan 222. The open distal end of the main section 228 is advantageously fluidly connected to means for forming a scoop.

[0065] The first cooling means, located to the left of the motor 202 in Figure 2, enables airflow along the arrow F1, which runs from left to right in this figure.

[0066] As the first fan 222 rotates, cool air from outside the motor 202 is drawn in, and this drawn-in air is sent to the inlet 226 of each flow path of the first system 224. The introduced air then flows through the main section 228 of each flow path of the first system 224, cooling the stator 206. As the air moves along the stator 206, it absorbs heat from the stator and its temperature rises. Finally, the hot air is discharged into the environment by means of forming a scoop, advantageously away from the motor 202.

[0067] The second cooling means is a second fan 223 integrated with the shaft 204 symmetrically with respect to the central plane M of the motor 202, and in this second embodiment, the second fan 223 is located inside the frame 210. More specifically, the second fan 223 is located inside the second flange 215 with respect to the enclosed volume 218.

[0068] The second cooling means includes a second flow path system 225 provided within the thickness of the axial wall, in conjunction with the second fan 223.

[0069] The second flow path system 225 comprises multiple N flow paths 225-i (Figure 3).

[0070] The flow path comprises, in order, a bent inlet section 227 and a main section 229 that is nearly straight and arranged parallel to axis A. The open proximal end of the inlet section 227 is fluidly connected to a second fan 223. The open distal end of the main section 229 is advantageously fluidly connected to means for forming a scoop.

[0071] The second cooling means, located to the right of the motor 202 in Figure 2, enables airflow along the arrow F2, which is directed from right to left in this figure.

[0072] As the second fan 223 rotates, cool air from outside the motor 202 is drawn in, and this drawn-in air is then sent to the inlet 227 of each flow path of the second system 225. The introduced air then flows through the main section 229 of each flow path of the second system 225, cooling the stator 206. As the air moves along the stator 206, it absorbs heat from the stator and its temperature rises. Finally, the hot air is discharged into the environment by means of forming a scoop, advantageously away from the motor 202.

[0073] Therefore, airflows F1 and F2 are created in opposite directions through the stator 206, thereby reducing the axial temperature gradient through the stator and, consequently, through the motor.

[0074] In the embodiment shown in Figure 2, the enclosed volume section 218 is defined by the axial wall in the radial direction and the first fan 222 and the second fan 223 in the longitudinal direction.

[0075] Therefore, the first flange 214 and the second flange 215, which are located further away from the first fan 222 and the second fan 223 with respect to the central plane M, have openings that allow air from outside the motor 202 to pass through the first fan 222 and the second fan 223.

[0076] Therefore, the axial wall is extended axially beyond the first fan 222 and the second fan 223 for mounting the shaft 204 and the frame 210, and receives the first flange 214 and the second flange 215.

[0077] Advantageously, the first fan 222 and the second fan 223 are made of a material with excellent thermal conductivity. The fans are made of aluminum, for example.

[0078] The first fan 222 and the second fan 223 constitute a wall called a cold wall, which facilitates heat exchange by conduction between the outside of the closed volume section 218 and the inside of the closed volume section 218, that is, heat exchange between the high-temperature air trapped inside the volume section 218 and the cold air outside the motor that is drawn in by the fans.

[0079] In this second embodiment, the boundaries 230 and 231 between the fixed frame 210 and the rotatable first fan 222 and second fan 223, respectively, are adapted to ensure the airtightness of the enclosed volume 218. Here, the term airtightness should be understood in a broad sense as a boundary that can prevent dust and dirt from entering the interior of the enclosed volume 218.

[0080] Similar to the first embodiment, the first system 224 and the second system 225 are the same, but on the frame 210 of the motor 202, they are arranged at an angle to each other in the plane transverse to axis A.

[0081] The explanation given for the first embodiment with respect to Figure 3 can be directly applied to the second embodiment as well. [Explanation of symbols]

[0082] 102, 202 motors 104, 204 shaft 106, 206 stator 107 Air Gap 108, 208 rotors 109 Channels 109 Thin plate 110, 210 frames 112 First end portion 112' Second end section 114, 214 First flange 115, 215 Second flange 116, 216 bearings 117, 217 bearings 118, 218 Closed volume part 122,222 First fan 123, 223 Second Fan 124, 224 First flow channel system 125, 225 Second flow channel system 126, 226 Entrance 127, 227 Entrance 128, 228 Main section 129, 229 Main section

Claims

1. A fan-cooled closed-type motor (202), A shaft (204) that defines the longitudinal axis (A) of the motor, A first transverse partition wall and a second transverse partition wall, A stator (206) integral with the axial wall and a rotor (208) integral with the shaft are located within a closed volume (218) whose axial direction is defined by the first transverse partition wall and the second transverse partition wall, and whose radial direction is defined by the axial wall (212) that constitutes the frame (210) of the motor. A flow path system (224) located outside the closed volume section (218) and passing through the surface or interior of the axial wall, and a fan (222) provided on the outside of the first transverse partition wall, the fan being attached to the shaft and circulating cooling air into the flow path system to cool the stator, It is a type that is equipped with The fan and the flow path system are a first fan and a first flow path system. In a motor (202) further comprising outside the enclosed volume section (218), a second flow path system (225) passing through the surface or interior of the axial wall, and a second fan (223) provided outside the second transverse partition wall and attached to the shaft to circulate cooling air through the second flow path system to cool the stator, The motor is symmetrical with respect to a transverse central plane (M) with respect to the motor's axis (A), and within the symmetrical motor, the first transverse partition wall is formed by the first fan (222), and the second transverse partition wall is formed by the second fan (223), and the motor is characterized in that it creates two flows (F1, F2) of cooling air circulating in opposite directions through the stator (206) in the first and second flow paths.

2. The motor according to claim 1, wherein the axial wall (212) is formed by combining two identical half-shells that are appropriately processed to form the flow channels of each flow channel system in the assembled state.

3. Further comprising a first flange (214) and a second flange (215), One flange is integral with the axial wall (212) and is connected to the shaft (204) via bearings (216, 217). The motor according to claim 1 or 2, wherein one flange is located further away from the fan with respect to the closed volume section (218) and has an opening that allows air to be drawn in by the fan.

4. The motor according to any one of claims 1 to 3, wherein the first fan (222) and the second fan (223) are made of aluminum.

5. The motor according to any one of claims 1 to 4, wherein the flow paths of the first flow path system (224) and the second flow path system (225) advance axially along the axial wall (212).

6. The motor according to claim 5, wherein the flow paths of the first flow path system (224) and the flow paths of the second flow path system (225) are regularly spaced in an annular manner by the axial wall (212), and each flow path of the first flow path system is sandwiched between two flow paths of the second flow path system.

7. The motor according to any one of claims 1 to 6, wherein, when N is the number of flow channels in each flow channel system, both the first flow channel system (224) and the second flow channel system (225) are angle-shifted from each other by an angle equal to π / N in the cross-section with respect to the longitudinal axis A.

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