JP6482058B2 - Frame with liquid jacket for electric motor - Google Patents

Description

  The present invention relates to an electric motor in which a stator enclosing a rotor extrapolated to a rotating shaft is arranged inside, and more particularly to a frame with a liquid jacket for a fully-closed electric motor.

  A fully-closed electric motor is known from Patent Document 1, for example. This includes an axially long inner cylinder part, an outer cylinder part that surrounds the inner cylinder part, and a pair of ends that are provided at both ends in the axial direction and close the hollow part between the inner cylinder part and the outer cylinder part. A frame having a plate portion. A rotating shaft is pivotally supported via a pair of bearings on brackets respectively connected to both ends in the longitudinal direction of the frame. A rotor made of a permanent magnet is extrapolated on the rotating shaft, and a stator configured by winding a coil around a yoke is disposed in the frame so as to surround the rotor.

In recent years, this type of fully-closed electric motor has been demanded to have a high output (for example, 200 kw or more) and a high-speed rotation (for example, 20000 min ⁻¹ ) while reducing the size and weight. Here, according to JIS B 0905-1992, the standard of the balance of the rigidity rotor of the rotating machine, the grade of the balance is defined in 11 stages from G0.4 to G4000. If the allowable residual unbalance is Upper (g · mm) and the radius of the rigid rotor that balances the balance is R (mm), the allowable unbalance mass m (g) is m = Upper / R. Even if G0.4 having the best quality is selected and manufactured, the unbalanced mass m remains.

Assuming that the forced external force acting on the rotating shaft induced by the unbalanced mass m around the rotating shaft is P, and the rotational speed of the rigid rotor (rotating shaft and rotor) is n (min ⁻¹ ), P = mR · (2π × n / 60) ² In this case, δ is the amount of bending deformation around the rotation axis at the location where the rotor is provided, M is the mass around the rotation axis at the location, C is the damping coefficient around the rotation axis at the location, If K is a flexural deformation spring constant around the rotation axis at the above location, the movement of forced vibration due to the swing of M · d ² δ / dt ² + C · dδ / dt + Kδ = mR · (2π × n / 60) ² Equation (1) holds.

  From the above equation (1), the amplitude of the vibration of the run-out caused by the forced external force P is proportional to the first power of the unbalanced mass m, amplified in proportion to the square of the rotation speed n, and the vibration acceleration of the run-out Increases in proportion to the amplification degree of the amplitude of this vibration. For this reason, as described above, the higher the rotation speed, the greater the vibrations around the rotating shaft caused by the unbalanced mass around the rotating shaft on which the rotor is extrapolated, and the motor itself. Vibration is also induced and increased, and it becomes difficult not only to suppress the amplitude due to vibration in the motor itself to a desired value (for example, 30 μm or less), but also to the bearing that supports the rotating shaft. The problem of causing damage arises.

  In addition, in the above-mentioned fully-closed motor, the smaller the size and weight and the higher the output, the more the amount of heat generated per unit volume in the motor itself, particularly due to copper loss and iron loss in the stator, increases significantly. -2100-2008 There is a problem that the temperature rise of the stator coil of the insulation type (for example, H type) defined in general rotating electric machines cannot be suppressed below the standard limit value.

  For example, Patent Document 2 discloses that a frame is provided with a liquid jacket to efficiently conduct heat generated in a stator coil to the frame. This is made by filling and fixing high thermal conductivity resin between the coil end of the stator coil and the outer sleeve supporting the outer periphery of the stator core, and with a passage wall around the outer sleeve on the frame side. A coolant passage surrounded by a partition wall that spirals around the outer sleeve is provided, and the heat transferred to the outer sleeve is circulated by circulating the coolant from the liquid inlet to the liquid outlet. It is configured to take away.

  However, in the above-mentioned Patent Document 2, the outer sleeve is a part independent of the frame, and the partition wall forming the coolant passage is provided so as to spiral around the outer sleeve. Yes. As a result, the flexural rigidity of the frame (EI) required to suppress the vibration of the small and lightweight motor itself that is induced by the vibration of the rotating shaft and to keep the vibration amplitude due to vibration below the desired value. It is extremely difficult to increase to a level that can satisfy the value of E (E is the longitudinal elastic modulus, I is the cross-sectional secondary moment). In addition, there is no specific description regarding the cooling performance, and details are unknown.

Japanese Patent No. 5354558 JP 2002-191149 A

  In view of the above points, the present invention suppresses vibration of the motor itself, which is induced by the vibration of the rotating shaft of the motor, and can reduce the fluctuation width due to the vibration, as well as from the stator caused by the loss of the motor. It is an object of the present invention to provide a frame with a liquid jacket for an electric motor capable of efficiently transferring heat to the liquid to cool the stator.

In order to solve the above problem, a frame with a liquid jacket of an electric motor of the present invention in which a stator surrounding a rotor extrapolated to a rotating shaft is disposed inside includes an inner cylindrical portion and an inner cylindrical portion that are long in the axial direction. And a pair of end plate portions that are provided at one end and the other end in the axial direction , respectively, and close the hollow portion between the inner cylinder portion and the outer cylinder portion. A plurality of hollow passages in the first, second, and third partition plates that are radially extended from the portion and are integrally connected to the outer cylinder portion and arranged in the circumferential direction at intervals. The first partition plate portion in one circumferential direction is in liquid-tight contact with the end plate portion at one end and the other end in the axial direction , and the odd-numbered number counted from the first partition plate portion to one circumferential direction. the second partition plate portion, extending from the end plate portion provided on the other axial end, between the end plate part provided on one axial end, specifications of the second The circumferential sides of the hollow passage of Riita portion together with the first communication portion for communicating are formed, the third partition plate portion of the even-numbered counting from the first partition plate portion in one circumferential direction, axial direction There is a second communication portion extending from the end plate portion provided at one end and communicating with the hollow passages on both sides in the circumferential direction of the third partition plate portion between the end plate portion provided at the other end in the axial direction. A continuous refrigerant circulation passage is formed while meandering in the axial direction from one of the hollow passages on both sides in the circumferential direction of the first partition plate portion to the other, and the cross-sectional shape along the radial direction of each hollow passage is The hollow portion is divided by the first, second, and third partition plate portions so that 16 or more hollow passages that are quadrangular or circular and have the same passage area are formed , and the inner tube portion and the outer tube portion When the first, all the second and third partition plate portion and a pair of end plates is integrally coupled Characterized in that it is configured.

  According to the present invention, the inner tube portion and the outer tube portion are connected and integrated by 16 or more partition plate portions functioning as reinforcing ribs so that the cross-sectional shape of the hollow passage is square or circular. Therefore, it is possible to effectively suppress the amplitude caused by the vibration of the motor itself, which is induced by the forced vibration of the rotating shaft, and the frame bending rigidity (E · It becomes possible to increase to a level that can satisfy the value of I). In addition, since a configuration in which 16 or more hollow passages having the same passage area are formed is adopted, the flow rate of the refrigerant (cooling water) flowing through the refrigerant circulation passage becomes as fast as possible and the entire length of the refrigerant circulation passage. And the heat transfer coefficient (α) between the refrigerant and the frame can be increased to a sufficient value. As a result, the amount of heat generated from the stator caused by the loss of the motor can be reduced. The stator can be cooled by efficiently transferring heat to the liquid. The upper limit of the number of hollow passages formed in the frame is appropriately set according to the discharge capacity (pressure) of the pump that supplies the refrigerant (cooling water) to the refrigerant circulation passage and the pressure loss in the internal passage.

In the present invention, when the cross-sectional shape of the hollow passage is a quadrangle, one set of opposite sides of the quadrangle facing each other is positioned in the radial direction, and the other set of opposite sides is positioned in the circumferential direction, respectively. The average length of the opposite side is equal to the average length of the opposite side of the other set, and the axial length of the first and second communicating portions is 1 to 3 times the average length of the set of opposite sides. You only have to set it. In the present invention, “equivalent” does not mean only the case where the lengths or the like exactly match, but includes “equivalent” as long as the above technical problem can be solved.

Sectional drawing of a fully-closed electric motor provided with the flame | frame with a liquid jacket of this invention. (A) is a perspective view showing a frame with a liquid jacket, (b) is a cross-sectional view taken along the line IIb-IIb in FIG. 2 (a), and (c) is a frame shown with the outer cylinder part removed. Partial development view. (A) And (b) is sectional drawing of the flame | frame with a liquid jacket which makes it correspond to FIG.2 (b). (A) is sectional drawing of the frame with a liquid jacket of a comparative product, (b) is the partial expanded view of the flame | frame shown in the state which removed the outer cylinder part. The graph of the experimental result which shows the effect of this invention. The figure which shows the analysis result of the heat transfer coefficient which shows the effect of this invention. The figure which shows the aspect of the temperature distribution around the stator based on the analysis result shown in FIG.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings, in which a frame with a liquid jacket according to the present invention is applied to a fully-closed electric motor of an embedded structure permanent magnet motor type. In the following, terms indicating directions such as “up” and “down” are based on FIG. 1, and the axial direction of the rotating shaft is the left-right direction. In FIG. "The right side, which is the transmission side of the electric motor, is defined as" rear ".

  With reference to FIG. 1, EM is an electric motor provided with the frame 1 with a liquid jacket of this embodiment. A front bracket 2a and a rear bracket 2b are connected to the front and rear of the frame 1 of the electric motor EM, respectively. A rotating shaft 4 is pivotally supported by the front and rear brackets 2a and 2b via a pair of front and rear bearings 3a and 3b. A rotor 5 made of a permanent magnet is extrapolated on the rotary shaft 4, and a stator 6 having a yoke 6 a and a coil 6 b wound around the yoke 6 a in the frame 1 so as to surround the rotor 5. Is fixedly arranged. A liquid cooling device CM is attached to the outer wall surface of the front bracket 2a. As the electric motor EM and the liquid cooling device CM (for example, Japanese Patent No. 5354558), since well-known ones can be used, further detailed description is omitted here.

  2 (a) to 2 (c), the frame 1 with a liquid jacket according to the present embodiment is made of, for example, a steel material, and has a cylindrical inner cylinder portion 11 that is long in the axial direction and has a cylindrical shape. A cylindrical outer tube portion 12 concentrically surrounding the tube portion 11, and a pair of end plate portions 14 a provided at both ends in the axial direction to close the hollow portion 13 between the inner tube portion 11 and the outer tube portion 12, 14b. The hollow portion 13 is a partition plate that extends radially from the inner cylinder portion 11 and is integrally connected to the outer cylinder portion 12 and is long in the axial direction and has a predetermined thickness arranged at equal intervals in the circumferential direction. The part 15 is partitioned into a plurality of hollow passages 13a (see FIGS. 2B and 2C).

  A predetermined partition plate portion 15 at one place in the circumferential direction is defined as a first partition plate portion 15a, and the partition plate portion 15a is in liquid-tight contact with the end plate portions 14a and 14b at both ends in the axial direction. The odd-numbered partition plate portion counted in the circumferential direction from the first partition plate portion 15a (clockwise in FIG. 2B) is defined as the second partition plate portion 15b, and the second partition plate portion 15b. Is a notch portion 16a as a first communication portion communicating with the hollow passages 13a on both sides in the circumferential direction of the second partition plate portion 15b between the rear end plate portion 14b as one end in the axial direction. Is formed. On the other hand, an even-numbered partition plate portion counted in one circumferential direction from the predetermined partition plate portion 15a is defined as a third partition plate portion 15c, and the third partition plate portion 15c is a front end plate serving as the other axial end. A notch portion 16b is formed between the portion 14a and a second communicating portion that communicates with the hollow passages 13a on both sides in the circumferential direction of the third partition plate portion 15c.

  Moreover, the cross-sectional shape along the radial direction of each hollow passage 13a is formed in a quadrangle with a small degree of deviation, so that 16 or more (28 in this embodiment) hollow passages 13a having the same passage area are formed. The hollow portion 13 is divided into first to third partition plate portions 15a to 15c. In this case, a pair of opposite sides 131 of the quadrangle facing each other is positioned in the radial direction, and the remaining other sets of opposite sides 132 are respectively positioned in the circumferential direction, and the average length of one set of opposite sides 131 and the other set of opposite sides 132 It is formed so that the average length is equivalent. In addition, when the cross-sectional shape of the hollow channel | path 13a is a square, it is not necessary for all the sides which define each hollow channel | path 13a to be comprised by the straight line, for example, the edge | side 131 located in radial direction is made into the inner cylinder part 11. It can be a concentric curve. Moreover, when making the structure which connected the inner cylinder part 11 and the outer cylinder part 12 integrally by the partition plate parts 15a-15c, methods, such as casting and welding, are used, and the hole as a hollow passage is used for a cylindrical member. You may make it pierce. Further, the length W in the axial direction of the notches 16a and 16b is set to 1 to 3 times the average length of the pair of opposite sides 132 so that the refrigerant flows smoothly in the communication portion. .

  The front bracket 2a is formed with an inflow port 17a that passes through the front end plate portion 14a and communicates with the hollow passage 13a located on one side in the circumferential direction of the first partition plate portion 15a. An outlet 17b that penetrates through the plate portion 14a and communicates with the hollow passage 13a located on the other circumferential side (the opposite side in the circumferential direction) of the first partition plate portion 15a is formed. As a result, a refrigerant circulation passage is formed in the frame 1 that continues from the inflow port 17a to the outflow port 17b while meandering in the axial direction from one to the other of the hollow passages 13a on both sides in the circumferential direction of the first partition plate portion 15a. The When the number of hollow passages 13a is an even number, both the inflow port 17a and the outflow port 17b are opened in the front end plate portion 14a, while the number of hollow passages 13a is an odd number. The inflow port 17a is opened in the front end plate portion 14a, and the outflow port 17b is opened in the rear end plate portion 14b.

  In the said embodiment, although what made the inner cylinder part 11 and the outer cylinder part 12 cylindrical was demonstrated to the example, it is not limited to this. If it demonstrates using the same code | symbol for the element and member same as the said embodiment, in the flame | frame 10a which concerns on the modification shown to Fig.3 (a), for example, the outer cylinder part 12 is polygonal (in a modification, octagonal shape) ). In this case, the one partition plate portion 151 is radially connected from the inner cylinder portion 11 toward each vertex of the polygonal outer cylinder portion 12 so as to be integrally connected to the hollow passage 13a to be formed in the hollow portion 13. Depending on the number (16 in the modified example), other partition plate portions 152 are provided between the partition plate portions 151 adjacent to each other. In this case, similarly to the above, the average length of one pair of opposite sides of the quadrangle facing each other is equal to the average length of the opposite sides of the other set.

  On the other hand, the example in which the cross-sectional shape along the radial direction of each hollow passage 13a is formed into a quadrangle with a small deviation degree has been described as an example, but the cross-sectional shape is not limited to this, and is shown in FIG. In the frame 10b according to still another embodiment, the cross-sectional shape along the radial direction of each hollow passage 13a is circular. In this case, the circular shape includes an elliptical shape and an oval shape. However, in any of the above cases, the first to third partition plate portions 15a to 15c may form 16 or more (28 in this embodiment) hollow passages 13a having the same passage area. It is necessary to divide the hollow portion 13.

  By the way, the following can be considered as a frame structure for cooling the stator 6 by heat exchange with the refrigerant. That is, referring to FIG. 4A and FIG. 4B, the frame FL as a comparative product is provided on each of the cylindrical inner cylinder portion A1, the polygonal outer cylinder portion A2, and both axial ends. And a pair of end plate portions C1 and C2 for closing the hollow portion B between the inner tube portion A1 and the outer tube portion A2. In the hollow part B, a partition plate part D extending radially from the inner cylinder part A1 and connected to the outer cylinder part A2 is arranged in the circumferential direction at equal intervals and is long in the axial direction and has a predetermined thickness. Are partitioned into a plurality of hollow passages B1. In this case, the hollow portion B is divided so that eight hollow passages B1 having a pentagonal cross-sectional shape are formed by connecting the tip of the partition plate portion D to substantially the midpoint of each side of the outer cylinder portion A2. doing. The hollow passage B1 is formed with a ridge E that protrudes radially outward from the inner cylindrical portion A1 and extends linearly in the axial direction from the both end plate portions C1 and C2, respectively. The contact area with the refrigerant is increased by the protrusion E that fulfills the above. As in the above embodiment, the refrigerant circulation passage that continues from the inlet F to the outlet G while meandering in the axial direction from one side to the other of the hollow passages B1 on both sides in the circumferential direction of the first partition plate portion D1 is a frame. It is formed in the FL.

  In the comparative product, even if the protrusions E are provided, the number of the hollow passages B1 is as small as eight, and the protrusions E are not connected and integrated with the outer cylindrical portion A2 of the frame FL. For this reason, in order to suppress the vibration in the electric motor EM itself induced by the forced vibration of the rotating shaft 4 and to make the amplitude due to the vibration below a predetermined value requested by the user, the required bending rigidity ( It has been found that it is difficult to increase the level of E · I) to a level that can satisfy the value, and eventually the bearings 3a and 3b provided on the front bracket 2a and the rear bracket 2b may be damaged. .

  Further, in the comparative product, the refrigerant is meandered and circulated along the refrigerant circulation passage provided with the protrusion E, and at this time, the cross-sectional shape of each hollow passage B1 is an irregular shape consisting of five sides with a large degree of deviation. As a result, the flow velocity distribution in the internal passage of the liquid, which is the refrigerant, is non-uniform and very turbulent. As a result, the heat transfer coefficient (α) between the refrigerant flowing in the refrigerant circulation passage and the frame FL having the ridge E is low and becomes a small value, and the heat generation of the stator 6 caused by the loss of the electric motor EM. It has been found that it is extremely difficult to reduce the amount by efficiently transferring the amount of heat to the liquid as the refrigerant through the frame FL to cool the stator 6 and to suppress the temperature rise of the coil 6b of the stator. It was.

  On the other hand, according to the above embodiment, the number of partition plate portions 15 contributing to the bending rigidity (E · I) of the frame 1 is increased so as to be at least twice as large as that of the comparative product. Since the plate portion 15 employs a configuration in which the inner cylinder portion 11 and the outer cylinder portion 12 are connected and integrated so that the cross-sectional shape of the hollow passage 13a is square or circular, the rotation axis is induced by forced vibration. The vibration amplitude of the motor itself is effectively suppressed, and the bending rigidity (E · I) value of the frame necessary to reduce the vibration amplitude due to the vibration to a desired value or less is increased to a level that can satisfy the value. It becomes possible. Note that the thickness of the partition plate portion 15 depends on the bending rigidity (E · I) due to the increase in the secondary moment (I) around the XX axis shown in FIG. ) (Longitudinal elastic modulus E is a material property value, and since it is a constant value, it is necessary to increase the value of the cross-sectional secondary moment I), and the partition plate portion from the inner cylinder portion 11 of the frame 1 The heat conduction analysis to No. 15 is performed, and it may be appropriately set in consideration of the improvement of the cooling performance so as to fulfill the function as a substitute for the protrusion E of the comparative product.

  In addition, since a configuration in which 16 or more hollow passages 13a having the same passage area are formed is adopted, the flow rate of the refrigerant (cooling water) flowing through the refrigerant circulation passage is as fast as possible as compared with the comparative product. At the same time, the flow velocity distribution over the entire length of the refrigerant circulation passage becomes substantially uniform, and the heat transfer coefficient (α) between the refrigerant flowing through the refrigerant circulation passage and the frame 1 of the invention according to the present embodiment is increased to a sufficient value. As a result, the amount of heat generated from the stator 6 caused by the loss of the electric motor EM can be efficiently transferred to the liquid to suppress the temperature rise of the stator 6 and thus the coil 6b. The upper limit of the number of hollow passages 13a formed in the frame 1 may be set according to the discharge capacity (pressure) of the pump that supplies the refrigerant (cooling water) to the fluid circulation passage and the pressure loss in the internal passage.

Next, in order to confirm the effect of the present invention, the following experiment was performed. In this case, a fully closed electric motor of an embedded structure permanent magnet synchronous motor type of 275 kw, 215 V / 440 V, 6000 min ⁻¹ / 20000 min ⁻¹ specifications is used, and the number of rotations of the rotating shaft 4 and the electric motor EM itself are changed by changing the frame type The correlation of the magnitude of vibration acceleration is obtained.

FIG. 5 shows vibration acceleration (m / s) in the electric motor EM itself with respect to the rotational speed (min ⁻¹ ) of the rotating shaft 4 when the comparative product frame FL and the frames 1 and 10a according to the present invention are used. ² ) is a graph showing the change in FIG. 5, and the one indicated by the line − ◯ − in FIG. 5 is the vibration in the frame FL (comparative product) shown in FIG. 4A with respect to the rotational speed (min ⁻¹ ) of the rotating shaft 4. A change in acceleration (m / s ² ), and a line indicated by a line ● − is a graph showing a change in amplitude (μm) in the frame FL (comparative product) with respect to the rotation speed (min ⁻¹ ) of the rotating shaft 4. Further, in FIG. 5, what is indicated by a line − □ − is a change in vibration acceleration (m / s ² ) in the frame 1 shown in FIG. 2C (related to the frame 1 shown in FIG. 2C). (Referred to as invention product 1), what is indicated by a -Δ- line is a change in vibration acceleration (m / s ² ) in the frame 10a shown in FIG. 3 (a) (frame 10a shown in FIG. 3 (a)). This is referred to as invention 2).

According to the above, in the comparative product, the vibration acceleration and amplitude due to the above-mentioned forced vibration change following a generally similar tendency as the number of rotations of the rotating shaft 4 is increased, and the vibration acceleration is around 30 m / s ^2. The amplitude due to vibration reached 29 um. In this case, there was a case where the bearings 3a and 3b supporting the rotating shaft 4 were damaged. In contrast, in the invention product 2, increasing the rotational speed of the rotary shaft 4, but a change in vibration acceleration, up to 18m / ^{s 2,} and the the inventions 1, a 7.1 m / ^{s 2} at the maximum You can see that

Here, when comparing the cross-sectional secondary moments around the XX axis between the comparative product and the inventive products 1 and 2, the comparative secondary moment (I) is 2.1 × 10 mm ⁴ in the comparative product. In contrast, the invention 2 has 3.5 × 10 mm ⁴ , and the invention 1 has 6.2 × 10 mm ⁴ , and the above-described electric motor is approximately in inverse proportion to the magnitude of the moment of inertia (I). It can be seen that the maximum acceleration value of the vibration of the EM main body is suppressed and reduced.

Next, as another experiment, a permanent magnet synchronous motor type fully closed motor similar to the above was used, and the amount of heat generated by the stator due to the loss of the motor at 275 kw, 215 V, 6000 min ⁻¹ was 16. The heat transfer coefficient (α) between the frame and the refrigerant was analyzed by changing the type of the frame at 47 kW, water at 25 ° C. as the refrigerant, the flow rate was 50 liters / min, and the results are shown in FIG. 6A is a comparative product, FIG. 6B is an invention product 1, and FIG. 6C is an invention product 2.

According to this, in the comparative product, the average heat transfer coefficient (α) over the entire length of the refrigerant circulation passage was 2400 w / (m ² · K). On the other hand, in invention 1, the average heat transfer coefficient (α) was 3697 w / (m ² · K). This is because the higher the flow rate of refrigerant (cooling water) in each internal passage, and the more uniform and uniform flow velocity distribution in each internal passage cross section, the more the heat transfer coefficient (α) is distributed. This is because the unevenness disappears. As a result, when the comparison product is 1, the average heat transfer coefficient (α) increases to about 1.16 times for the invention product 2 and about 1.54 times for the invention product 1, and it becomes a refrigerant through the frame. It can be seen that the stator can be cooled by efficient heat transfer.

Further, FIG. 7 is a diagram showing an aspect of temperature distribution around the stator subjected to thermal fluid analysis for each frame based on the analysis result of the heat transfer coefficient. In this case, when the calorific value of the stator generated due to the loss of the motor is 16.47 kw, when the respective temperature rise values at the stator inner diameter at which the temperature rise value is maximum are compared, the case of Invention 2 Can lower the temperature increase value by 5.63K compared to the comparative product, and the invention product 1 can decrease the temperature increase value by 9.12K, and further the flow rate can be kept at 80 with the water temperature kept the same. If it is increased to liters / min, the average heat transfer coefficient increases to 5298 w / (m ² · K), so the temperature rise value can be lowered to 11.21 K, and the temperature rise of the stator coil can be reduced to the standard limit value. It was confirmed that the following can be suppressed.

In addition, when a circular hole is drilled so as to have substantially the same area as the cross-sectional area of the square hollow passage shown in FIG. 3B, the cross-sectional secondary moment around the XX axis is 6.45 × 10 mm. ⁴ and the bending rigidity (E · I) is almost the same, and if the coolant temperature and the flow rate are the same, the average heat transfer coefficient over the entire length of the coolant circulation path and the stator temperature increase The value can be suppressed and reduced equivalent to that of Invention Product 1.

EM: Fully enclosed motor (electric motor), 1, 10a, 10b ... Frame with liquid jacket, 11 ... Inner cylinder part, 12 ... Outer cylinder part, 13 ... Hollow part, 13a ... Hollow passage, 14a, 14b ... End plate part, DESCRIPTION OF SYMBOLS 15 ... Partition plate part, 15a ... Predetermined partition plate part of one circumferential direction, 15b ... Odd-numbered partition plate part counted to one circumferential direction from a predetermined partition plate part, 15c ... Circumferential direction from predetermined partition plate part Even-numbered partition plates 16a, 16b ... notches (communications).

Claims (2)

In the frame with the liquid jacket of the electric motor in which the stator surrounding the rotor extrapolated to the rotation shaft is arranged inside,
A pair of ends for closing the hollow portion between the inner cylinder portion and the outer cylinder portion, which are respectively provided at one end and the other end in the axial direction. And a hollow portion extending radially from the inner cylinder portion and integrally connected to the outer cylinder portion, the first, second and second axially longitudinally arranged at intervals in the circumferential direction Partitioned by a third partition plate into a plurality of hollow passages,
The first partition plate portion of the circumferential one place liquid-tight manner against the end plate portion in the axial direction of the one end and the other end, the odd-numbered second partition counted from the first partition plate portion in one circumferential direction The plate portion extends from the end plate portion provided at the other end in the axial direction , and communicates with the hollow passages on both sides in the circumferential direction of the second partition plate portion between the end plate portion provided at the one end in the axial direction. together with the first communicating portion is formed, the third partition plate portion of the even-numbered counting from the first partition plate portion in one circumferential direction, extending from the end plate part provided on one axial end, axially Between the end plate portion provided at the other end , second communication portions are formed to communicate the hollow passages on both sides in the circumferential direction of the third partition plate portion, and both sides in the circumferential direction of the first partition plate portion are formed. A continuous refrigerant circulation passage is formed while meandering in the axial direction from one of the hollow passages to the other,
The hollow portions of the first, second, and third partition plates are formed so that the cross-sectional shape along the radial direction of each hollow passage is a square or a circle and 16 or more hollow passages having the same passage area are formed. Of the electric motor, wherein the inner cylinder part, the outer cylinder part, the first, second and third partition plate parts, and the pair of end plate parts are connected and integrated. Frame with liquid jacket. The liquid jacketed frame of the electric motor according to claim 1, wherein the hollow passage has a quadrangular cross-sectional shape.
A pair of opposite sides of the quadrangle facing each other is positioned in the radial direction, and the other pair of opposite sides is positioned in the circumferential direction, and the average length of one set of opposite sides is equal to the average length of the other set of opposite sides. The length of the first and second communicating portions in the axial direction is set to a length of 1 to 3 times the average length of the pair of opposite sides .