JP5955235B2 - Electric motor - Google Patents

Description

  The present invention relates to an electric motor that forcibly cools by circulating a refrigerant around an outer periphery of a stator.

  4 is a longitudinal sectional perspective view showing a cooling jacket and a frame of a conventional motor shown as a comparative example, FIG. 5 is a partial longitudinal sectional view showing a conventional motor, and FIG. 6 is a diagram of a conventional cooling jacket. It is a cross-sectional view showing a refrigerant inflow groove.

  A conventional electric motor 200 shown in FIGS. 4 to 6 is used for a general machine tool, and includes a columnar rotor 10, a cylindrical stator 20 to which a coil 21 is attached and which houses the rotor 10, A cylindrical cooling jacket 230 that is externally fitted to the stator 20 and provided with a refrigerant groove 34 on the outer periphery thereof, and a cylindrical frame 40 that is externally fitted to the cooling jacket 230 and closes the outer release surface of the refrigerant groove 34 are provided. .

  The refrigerant groove 34 includes an annular refrigerant inflow groove 31 provided on one axial end side of the cooling jacket 230, an annular refrigerant outflow groove 32 provided on the other axial end side, the refrigerant inflow groove 31 and the refrigerant outflow groove. And a spiral groove 33 having a start end 33 a communicating with the side portion of the refrigerant inflow groove 31 and a terminal end (not shown) communicating with the side portion of the refrigerant outflow groove 32. The refrigerant inlet 41 provided in the frame 40 and communicating with the refrigerant inflow groove 31 is shifted from the start end 33 a of the spiral groove 33 by 45 ° in the circumferential phase.

  In the conventional electric motor 200, the refrigerant flows into the refrigerant inflow groove 31 from the refrigerant inlet 41, passes through the clockwise channel 31 a and the counterclockwise channel 31 b, and enters the spiral groove 33 from the start end 33 a of the spiral groove 33. Flows in, passes through the spiral groove 33, enters the refrigerant outlet groove 32 from the end (not shown) of the spiral groove 33, passes through the clockwise flow path and the counterclockwise flow path (both not shown). It flows out of the refrigerant outlet 42 provided in the frame 40 and forcibly cools the electric motor 200.

  Conventionally, the wall surface of the casing that houses the electric motor is divided along the outer peripheral side of the electric motor, the divided wall surfaces are combined with the partition plate installed along the divided wall surface, and along the outer peripheral side. The recesses formed in the divided wall surfaces are partitioned by a partition plate into a plurality of layers of passages along the outer peripheral side, and the plurality of layers of passages are formed into a single refrigerant channel by the communication holes provided in the partition plate. A cooling device for a formed electric motor is disclosed (for example, see Patent Document 1).

  In addition, the electric motor includes a cylindrical case that accommodates the rotor and the stator, and the case includes a cooling space that is formed substantially in the circumferential direction in the inside thereof and that can circulate a fluid. The space has an inlet through which the fluid flows, and is positioned on one side in the axial direction of the case with respect to the first cooling portion capable of circulating the fluid over substantially the entire circumferential direction, A second cooling part capable of circulating a fluid over substantially the entire circumferential direction, and located in a region in a predetermined range in the circumferential direction on the side opposite to the radial direction of the case with respect to the inlet, and in the first cooling part In a region in a predetermined range in the circumferential direction on the side opposite to the first merging portion in the radial direction with respect to the first merging portion, the fluid merges and the first cooling portion and the second cooling portion communicate with each other. Located and said second cooling Motor wherein the fluid of the inner can and a second junction section for merging is disclosed (for example, see Patent Document 2).

  Further, in a high-speed generator comprising a rotor, a stator concentrically arranged on the rotor and arranged on the outer peripheral side of the rotor, and a case concentric to the stator and enclosing the stator, the stator corresponds to the outer circumferential surface of the stator. A high-speed generator having a cooling flow path spirally provided in a case, the cooling flow path having a cooling water inlet at an axially central portion of the case and cooling water outlets at both axial ends. Is disclosed (for example, see Patent Document 3).

Japanese Patent No. 3622582 JP 2010-209933 A Japanese Patent Laid-Open No. 01-274636

  However, in the conventional electric motor 200 shown in FIGS. 4 to 6, the refrigerant inlet 41 provided in the frame 40 and communicating with the refrigerant inflow groove 31 is shifted in the circumferential phase by 45 ° from the start end 33 a of the spiral groove 33. Since the flow path length of the clockwise flow path 31a in the inflow groove 31 and the flow path length of the counterclockwise flow path 31b are different, there is a problem that the flow of the refrigerant becomes uneven and the cooling efficiency is poor. Moreover, since the flow path length of the spiral groove 33 is long, there is a problem that the pressure loss increases and the necessary refrigerant flow rate cannot be secured. In addition, there is a problem that the power consumption of the refrigerant circulation device is large because the constant refrigerant flow rate is always set in accordance with the operating condition of the machine tool that maximizes the amount of heat generated by the electric motor 200.

  In addition, according to the conventional technique described in Patent Document 1 or 2, the refrigerant concentrates in the communication hole provided in the partition plate or the first junction, and therefore, the refrigerant drifts and the heat distribution varies. There is a problem. In addition, there is a problem that the flow passage area of the communication hole or the first merging portion is narrow, the pressure loss is locally increased, and the cooling flow rate is restricted. Further, since the refrigerant flow paths are not continuous, there is a problem that the number of processing steps for the flow paths increases and the cost increases.

  Further, according to the conventional technique described in Patent Document 3, since the cooling flow path is branched to both sides at the central portion in the axial direction, there is a problem that the flow rate becomes half and the cooling efficiency is deteriorated. In addition, when the total motor length is long and the cooling flow path is long, there is a problem that it is difficult to secure a cooling flow rate.

  The present invention has been made in view of the above, and an object of the present invention is to obtain an electric motor that has high cooling efficiency, can secure a necessary refrigerant flow rate, and consumes less power in the refrigerant circulation device.

  In order to solve the above-described problems and achieve the object, the present invention includes a columnar rotor, a cylindrical stator to which a coil is mounted and which accommodates the rotor, and an outer periphery fitted to the stator. An electric motor comprising: a cylindrical cooling jacket provided with a refrigerant groove; and a cylindrical frame that is externally fitted to the cooling jacket and closes an outer release surface of the refrigerant groove, wherein the refrigerant groove is in the axial direction of the cooling jacket. An annular refrigerant inflow groove provided at a predetermined position, an annular refrigerant outflow groove provided at a position axially spaced from the refrigerant inflow groove, and between the refrigerant inflow groove and the refrigerant outflow groove A refrigerant inlet that is provided in the frame and that communicates with the refrigerant inflow groove, having a start end that communicates with a side portion of the refrigerant inflow groove and a terminal end that communicates with a side portion of the refrigerant outflow groove Before Starting the circumferential phase of the spiral groove, characterized in that the offset 180 °.

  According to the present invention, an electric motor having high cooling efficiency and ensuring a necessary refrigerant flow rate is obtained.

FIG. 1 is a partial longitudinal sectional view showing Embodiment 1 of an electric motor according to the present invention. FIG. 2 is a cross-sectional view showing a refrigerant inflow groove of the cooling jacket according to the first embodiment. FIG. 3 is a system configuration diagram showing a refrigerant flow rate control system according to the second embodiment of the electric motor according to the present invention. FIG. 4 is a longitudinal sectional perspective view showing a cooling jacket and a frame of a conventional electric motor shown as a comparative example. FIG. 5 is a partial longitudinal sectional view showing a conventional electric motor. FIG. 6 is a cross-sectional view showing a refrigerant inflow groove of a conventional cooling jacket.

  Embodiments of an electric motor according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
1 is a partial longitudinal sectional view showing a first embodiment of the electric motor according to the present invention, and FIG. 2 is a transverse sectional view showing a refrigerant inflow groove of the cooling jacket of the first embodiment.

  The electric motor 91 of the first embodiment is used for a general machine tool, and as shown in FIGS. 1 and 2, a cylindrical rotor 10 and a coil 21 are mounted and the rotor 10 is accommodated therein. Cylindrical stator 20, cylindrical cooling jacket 30 that is externally fitted to stator 20 and provided with refrigerant grooves 34 and 35 on the outer periphery, and an outer release surface of refrigerant grooves 34 and 35 that are externally fitted to cooling jacket 30. And a cylindrical frame 40.

  The refrigerant groove 34 is an annular refrigerant inflow groove 31 provided at a predetermined position in the axial direction (one axial end portion) of the cooling jacket 30 and a position (a central portion in the axial direction) spaced from the refrigerant inflow groove 31 by a predetermined distance in the axial direction. ) Provided in the annular refrigerant outflow groove 32, the refrigerant inflow groove 31 and the refrigerant outflow groove 32, the start end 33a communicates with the side of the refrigerant inflow groove 31, and the end (not shown) is the refrigerant. And a spiral groove 33 communicating with the side of the outflow groove 32. The refrigerant inlet 41 provided in the frame 40 and communicating with the refrigerant inflow groove 31 is 180 ° out of the circumferential phase with the start end 33 a of the spiral groove 33. Further, the coolant outlet 42 provided in the frame 40 and communicating with the coolant outlet groove 32 is 180 ° out of the circumferential phase with respect to the terminal end (not shown) of the spiral groove 33.

  The cooling jacket 30 is provided with another refrigerant groove 35, and the other refrigerant groove 35 is an annular refrigerant provided next to the refrigerant outflow groove 32 of the cooling jacket 30 (axially central portion). Between the inflow groove 36, an annular refrigerant outflow groove 37 provided at a position spaced apart from the refrigerant inflow groove 36 in the axial direction (the other end in the axial direction), and between the refrigerant inflow groove 36 and the refrigerant outflow groove 37. And a spiral groove 38 having a start end (not shown) communicating with the side portion of the refrigerant inflow groove 36 and a terminal end (not shown) communicating with the side portion of the refrigerant outflow groove 37. A refrigerant inlet 46 provided in the frame 40 and communicating with the refrigerant inflow groove 36 is 180 ° out of the circumferential phase with respect to the starting end (not shown) of the spiral groove 38. The refrigerant outlet 47 provided in the frame 40 and communicating with the refrigerant outlet groove 37 is 180 ° out of the circumferential phase with respect to the terminal end (not shown) of the spiral groove 38.

  As described above, in the electric motor 91 of the first embodiment, the refrigerant inlet 41 provided in the frame 40 and communicating with the refrigerant inflow groove 31 is shifted in the circumferential phase by 180 ° from the start end 33a of the spiral groove 33. Since the flow path length of the clockwise flow path 31a in the refrigerant inflow groove 31 and the flow path length of the counterclockwise flow path 31b are the same, the flow of the refrigerant becomes uniform and the cooling efficiency is high. Moreover, since the flow path length of the spiral grooves 33 and 38 is short, a pressure loss is small and a required refrigerant | coolant flow volume is securable.

Embodiment 2. FIG.
FIG. 3 is a system configuration diagram showing a refrigerant flow rate control system according to the second embodiment of the electric motor according to the present invention. In the refrigerant flow rate control system 92 for the electric motor according to the second embodiment, the same parts as those of the electric motor 91 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The refrigerant flow rate control system 92 for the electric motor according to the second embodiment includes an electromagnetic flow rate control valve 50 that is connected to the refrigerant inlet ports 41 and 46 and controls the refrigerant flow rate flowing into the refrigerant inlet ports 41 and 46, and the load value of the machine tool. An NC unit 70 that outputs as a control factor of the electromagnetic flow control valve 50, and a relationship between the load value and the refrigerant flow rate as a correlation table, the refrigerant flow rate is determined based on the load value, and an excitation current command is sent to the electromagnetic flow control valve 50 And a comparison operation unit 60 for outputting.

  According to the refrigerant flow rate control system 92 of the electric motor according to the second embodiment, the refrigerant flow rate of the electric motor 91 is adjusted according to the load value (for example, the cutting amount) of the machine tool, so that the power consumption of the refrigerant circulation device is saved. be able to.

  10 Rotor, 20 Stator, 21 Coil, 30 Cooling jacket, 34, 35 Refrigerant groove, 31, 36 Refrigerant inflow groove, 32, 37 Refrigerant outflow groove, 33, 38 Spiral groove, 31a Clockwise flow path, 31b Counterclockwise flow Road, 33a Start end, 40 frame, 41, 46 Refrigerant inlet, 42, 47 Refrigerant outlet, 50 Electromagnetic flow control valve, 60 Comparison operation unit, 70 NC unit, 91 Electric motor, 92 Refrigerant flow control system for electric motor.

Claims (4)

A cylindrical rotor, a cylindrical stator that is fitted with a coil and accommodates the rotor therein, a cylindrical cooling jacket that is externally fitted to the stator and has a coolant groove on the outer periphery, and an external fit to the cooling jacket And a cylindrical frame that closes the outer release surface of the refrigerant groove,
The refrigerant groove includes an annular refrigerant inflow groove provided at a predetermined position in the axial direction of the cooling jacket, an annular refrigerant outflow groove provided at a position spaced a predetermined distance in the axial direction from the refrigerant inflow groove, A spiral groove provided between the refrigerant inflow groove and the refrigerant outflow groove and having a start end communicating with the side portion of the refrigerant inflow groove and a terminal end communicating with the side portion of the refrigerant outflow groove. And the refrigerant inlet that communicates with the refrigerant inflow groove is 180 ° out of phase with the starting end of the spiral groove.   2. The electric motor according to claim 1, wherein a coolant outlet provided in the frame and communicated with the coolant outlet groove has a circumferential phase shifted from the end of the spiral groove by 180 °.   The electric motor according to claim 1, comprising a plurality of refrigerant flow paths including the refrigerant inlet, the refrigerant inlet groove, the spiral groove, the refrigerant outlet groove, and the refrigerant outlet.   An electromagnetic flow control valve connected to the refrigerant inlet for controlling a flow rate of refrigerant flowing into the refrigerant inlet, an NC unit for outputting a load value of a machine tool as a control factor of the electromagnetic flow control valve, and the load value; A comparison operation unit that has a relationship with a refrigerant flow rate as a correlation table, determines a refrigerant flow rate based on the load value, and outputs an excitation current command to the electromagnetic flow control valve. 4. The electric motor according to any one of 3.

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