TWM517473U - Liquid cooling type casing with dual helical coolant flow passages - Google Patents

Description

Liquid-cooled housing with double-spiral coolant flow path

The present invention relates to a liquid-cooled casing, and more particularly to a liquid-cooled casing having a double-screw coolant flow passage.

At present, in the construction of products such as motors or generators, the rotor and the stator are coaxially arranged inside a casing. When the rotor rotates relative to the stator, the motor or generator is converted into heat energy due to energy loss. In order to avoid the working temperature of the motor or generator running too high, and to improve the cooling and cooling efficiency, the existing motor or generator adopts a liquid-cooled casing structure, so that the circulating fluid is used for heat exchange through the inside of the casing. And achieve the purpose of cooling and cooling.

The liquid-cooled casing structure which is known to be applied to the field of motors or generators, the "motor with oil circuit circulation" disclosed in the invention patent publication No. I484733, and the disclosure of the invention patent No. I477040 "Circulating refrigerant cooling motor", and "double-cycle refrigerant cooling motor" disclosed in the publication No. I477041.

In the "motor with oil circuit circulation" disclosed in the above-mentioned publication No. I484733, the main part of the motor body is provided with an oil passage space at both ends of the bearing, and each oil passage space is separately entered. The oil pipe and a return pipe are connected to a fuel tank, and a pump is used to circulate the cooling oil in the oil tank between the oil pipe and the oil return pipe and the oil passage space, thereby cooling the peripheral portion of the bearing at both ends of the motor.

However, the front-end "motor with oil circulation" only provides cooling function to the peripheral part of the bearing at both ends of the motor body. The middle part of the motor body does not have a cooling function at all, and it cannot provide a better cooling effect to the whole motor, and both ends of the motor body The problem of a large temperature difference from the middle section.

In the "double-cycle refrigerant cooling motor" disclosed in the above-mentioned publication No. I477040 and the publication No. I477041, the main purpose is to install a stator and a rotor in the stator in a set of double-cycle casings, the double-cycle casing A spiral flow passage is arranged, and a cooling oil conduit is respectively connected to the front and rear ends of the spiral flow passage, and a cooling oil is circulated therein to form a refrigerant evaporator. The middle section of the stator is a channel type silicon steel sheet and a penetrating type. The silicon steel sheet is formed, and a plurality of stator oil injection ports are formed through the inner and outer sides of the stator, and the channel type silicon steel sheet further forms a certain outer oil passage between the inner side of the double circulation outer casing, and the outer oil passage of the stator is connected to the two ends of the double circulation outer casing. Cooling oil conduit, a gap between the rotor and the stator forms a cylindrical oil passage, and an oil pump blade is arranged at each of the front and rear ends of the rotor. The oil pump blade can extract cooling oil from the tubular oil passage and then cool through both ends of the double-circulation shell. The oil pipe is introduced into the outer oil passage of the stator, and then introduced into the tubular oil passage through the stator oil injection port to form a cooling oil inner circulation loop, so that the motor uses the inner and outer refrigerants to circulate and flow. Cooling purposes.

However, the dual-cycle refrigerant cooling motor uses the internal and external double-cycle cooling mechanism to achieve motor cooling. Among them, the refrigerant evaporator adopts a loop design of a single spiral flow passage, and accumulates heat due to the flow direction of the cooling oil at one end of the double-circulation outer casing having a cooling oil outlet, so that the temperature difference between the two ends of the double-circulation casing shaft is large. . Furthermore, the motor utilizes a cooling oil pipe at both ends of the double-cycle casing to combine the channel-shaped silicon steel sheet of the stator with the stator outer oil passage provided between the inner sides of the double-cycle outer casing, and a gap between the rotor and the stator forms a cylindrical oil passage, and An oil pump blade is arranged at each of the front and rear ends of the rotor to form a cooling oil inner circulation loop. The structure of the inner loop of the cooling oil is complicated, manufacturing and maintenance are difficult, and it cannot be applied to various motors or generators, and is double cycled. The arrangement of the cooling oil inner circulation circuit between the outer casing, the stator and the rotor is likely to adversely affect the operation of the motor or the generator.

The main purpose of this creation is to provide a liquid-cooled casing with a double-spiral coolant flow path, which solves the problems of poor cooling performance of the existing liquid-cooled casing and complicated cooling cycle.

In order to achieve the foregoing, the liquid-cooled casing with a double-spiral coolant flow path proposed by the present invention comprises: a casing comprising a casing wall defining a central axis, the casing wall Forming a shaft hole penetrating the shell wall along the central axis, the opposite ends of the shell wall along the central axis are respectively a first end and a second end; a first spiral tube is disposed on the shell of the shell Inside the wall, the first spiral tube includes a plurality of first spiral tube units, and the plurality of first spiral tube units are continuously spirally wound with respect to the central axis according to a spiral radius and a spiral lead, the first spiral tube having a first coolant inlet extending beyond the first end of the casing wall, the first coil having a first coolant outlet extending beyond the second end of the casing wall; and a second coil disposed on the casing Inside the shell wall of the body, the second spiral tube comprises a plurality of second spiral tube units, the plurality of second spiral tube units are continuously spirally wound according to the central axis along the spiral radius and the spiral lead, the second Second spiral tube of spiral tube And the first spiral tube unit of the first spiral tube is misaligned, the second spiral tube has a second coolant outlet extending beyond the first end of the shell wall, and the second coil has a second wall extending from the shell wall a second coolant inlet outside the end.

It is created by a liquid-cooled casing with a double-spiral coolant flow channel, which is applied to products such as motors or generators. The liquid-cooled casing is mainly provided with an equal diameter in the shell wall of the casing. The first and second spiral tubes of the circumferential spiral form a double spiral coolant flow passage for introducing the flowing coolant to carry away the heat generated by the operation of the motor or the generator, and using the first and second spiral tubes The first and second coolant inlets respectively located at the two ends of the shell wall simultaneously input the coolant in both directions, and the coolant after the heat exchange is separately discharged from the first and second coolant outlets at both ends of the shell wall of the shell. And an innovative double-screw coolant flow path structure such as staggered arrangement of the spiral tubes of the two spiral tubes, so that the first coolant of the first spiral tube of the low-temperature coolant is input during use of the liquid-cooled casing The second coolant outlet of the second spiral tube of the inlet and the output endothermic coolant is located at the first end of the casing wall, and outputs the first coolant outlet of the first spiral tube of the coolant after the endothermic heat and the second inlet of the input low temperature coolant Second cooling of the spiral tube The inlet is located at the second end of the casing wall such that the overall temperature of the liquid-cooled casing does not accumulate heat at one end of the casing due to the flow direction of the coolant, and the input position of the coolant in the double-spiral coolant flow passage of the casing, The temperature difference between the output position and the middle section of the coolant flow path is small, solving the problem that the temperature gradient of the coolant of the existing motor or generator in the internal flow passage of the casing is large, and the temperature of the internal components of the motor or the generator is more balanced, and Can run stably.

According to the technical means proposed in the prior art, the present invention can at least create a liquid-cooled casing having a double-spiral coolant flow path as shown in FIGS. 1 to 7. As can be seen, the liquid-cooled casing having a double-spiral coolant flow passage includes a casing 10A, 10B, 10C, a first spiral pipe 20, and a second spiral pipe 30.

As shown in FIG. 1 , FIG. 5 , FIG. 6 , and FIG. 7 , the casings 10A, 10B, and 10C are members made of a heat conductive material, and include a shell wall 11A, 11B, and 11C, and shell walls 11A and 11B. A central axis 100 is defined in 11C, and a shaft hole 14 is formed in the casing wall 11A, 11B, 11C penetrating the casing wall 11A, 11B, 11C along the central axis 100, and the casing wall 11A, 11B, 11C is along the central axis 100. The opposite ends of the direction are a first end 12 and a second end 13, respectively.

As shown in FIG. 1 , FIG. 5 , FIG. 6 , and FIG. 7 , the first spiral tube 20 is a member made of a heat conductive material, and is disposed on the shell walls 11A and 11B of the housings 10A, 10B, and 10C. Inside the 11C, the first spiral tube 20 includes a plurality of first spiral tube units 21, 31. The plurality of first spiral tube units 21, 31 follow a spiral radius and a spiral lead continuous spiral with respect to the central axis 100. Wrapped around the periphery of the shaft hole 14, as shown in FIGS. 1 and 2, the first spiral tube 20 has a first coolant inlet 22 extending beyond the first end 12 of the casing wall 11A, the first coil 20 having A first coolant outlet 23 extending beyond the second end 13 of the casing wall 11A allows the coolant to be supplied from the first coolant inlet 22 and discharged from the first coolant outlet 23.

As shown in FIG. 1 , FIG. 5 , FIG. 6 , and FIG. 7 , the second spiral tube 30 is a member made of a heat conductive material, and is disposed on the shell walls 11A and 11B of the housings 10A, 10B, and 10C. Inside the 11C, the second spiral tube 30 includes a plurality of second spiral tube units 21, 31, and the plurality of second spiral tube units 21, 31 follow the spiral radius and the spiral lead continuous spiral with respect to the central axis 100. The second spiral tube units 21, 31 of the second spiral tube 30 and the first spiral tube units 21, 31 of the first spiral tube 20 are arranged in a misaligned manner around the periphery of the shaft hole 14. As shown in FIGS. 1 and 2, the second spiral tube 30 has a second coolant outlet 33 extending beyond the first end 12 of the casing wall 11A, and the second coil 30 has a second portion extending from the casing wall 11A. A second coolant inlet 32 outside the end 13. The coolant can be input from the second coolant inlet 32 and discharged from the second coolant outlet 33. The direction of the coolant in the second coil 30 is opposite to the direction of the coolant in the first coil 20. .

As shown in FIG. 1 and FIG. 2, the first coolant inlet 22 and the first coolant outlet 23 of the first spiral tube 20 of the present invention and the second coil of the second spiral tube 30 are separately disclosed. Various preferred embodiments of the coolant inlet 32 and the second coolant outlet 33, wherein, in the preferred embodiment shown in FIG. 1, the first coolant inlet 22 and the second coil of the first spiral tube 20 The second coolant outlet 33 of the tube 30 can project radially from the first end 12 of the shell wall 11A toward the side, the first coolant outlet 23 of the first coil 20 and the second coil 30 The coolant inlet 32 extends radially from the interior of the second end 13 of the casing wall 11A toward the side. Alternatively, as shown in the preferred embodiment of FIG. 2, the first coolant inlet 22 of the first spiral tube 20 and the second coolant outlet 33 of the second coil 30 may be from the first end 12 of the casing wall 11A. The first coolant outlet 23 of the first spiral tube 20 and the second coolant inlet 32 of the second spiral tube 30 are respectively separated from the inside of the second end 13 of the shell wall 11A, respectively. Extending outward on both sides of the radial direction.

In addition to the above, the first coolant inlet of the first spiral tube and the second coolant outlet of the second spiral tube may respectively protrude from the inside of the first end of the shell wall in the direction of the central axis, the first spiral tube The first coolant outlet and the second coolant inlet of the second coil extend from the interior of the second end of the casing wall in the direction of the central axis, respectively.

Various embodiments of the housing in the present liquid-cooled enclosure are separately disclosed in the various preferred embodiments shown in Figures 3-7. In the preferred embodiment shown in FIGS. 3 and 4, the casing wall 11A includes an inner casing portion 15A and an outer casing portion 16A. The outer casing portion 16A forms a spiral groove 17A toward the inner wall surface of the inner casing portion 15A. The first spiral tube 20 and the second spiral tube 30 are disposed in the two spiral grooves 17A. The outer casing portion 16A is sleeved on the outer circumferential surface of the inner casing portion 15A, and the first spiral tube 20 is in contact with the second spiral tube 30. The inner casing portion 15A and the outer casing portion 16A.

As shown in the preferred embodiment of FIG. 5, the casing wall 11B includes an inner casing portion 15B and a casing portion 16B. The inner casing portion 15B forms a spiral groove 17B toward the outer wall surface of the outer casing portion 16B. The tube 20 and the second spiral tube 30 are respectively disposed in the two spiral grooves 17B. The outer shell portion 16B is sleeved on the outer peripheral surface of the inner shell portion 15B, and the first spiral tube 20 and the second spiral tube 30 are in contact with the inner shell portion. 15B and outer casing portion 16B.

As shown in the preferred embodiment of FIG. 6 and FIG. 7, the casing wall 11C includes an inner casing portion 15C and an outer casing portion 16C. The inner casing portion 15C forms two sets of inner semi-spiral grooves 171C toward the outer wall surface of the outer casing portion 16C. The outer casing portion 16C is composed of two half-shell portions 161C which are opposite to each other. The two half-shell portions 161C can be integrally fixed by means of welding or screwing. The outer casing portion 16C can be sleeved on the outer circumferential surface of the inner casing portion 15C. The outer casing portion 16C forms two sets of outer semi-spiral grooves 172C toward the inner wall surface of the inner casing portion 15C, and the two outer semi-spiral grooves 172C and the inner half of the two groups The spiral groove 171C corresponds to and synthesizes two spiral grooves 17C. The first spiral tube 20 and the second spiral tube 30 are respectively disposed in the two spiral grooves 17C, and the first spiral tube 20 and the second spiral tube 30 are in contact with the inner shell. The portion 15C and the outer casing portion 16C.

The liquid-cooled casing having the double-spiral coolant flow passage can be applied to products such as motors or generators. Taking the preferred embodiment shown in FIGS. 1 and 3 as an example, the stator of the motor or generator is The rotor assembly is disposed in the shaft hole 14 of the casing 10A of the liquid-cooled casing, and the liquid-cooled casing is the first coolant inlet 22 of the first spiral pipe 20 and the second coolant inlet 22 of the second spiral pipe 20 The coolant inlet 32 is connected to the coolant output end of the coolant circulation system, and the coolant of the coolant circulation system is connected to the first coolant outlet 23 of the first spiral tube 20 and the second coolant outlet 33 of the second spiral tube 30. Recycling end. When the motor or the generator is running, the rotor rotates at a high speed in the stator, and the heat generated by the energy loss is transmitted to the casing wall 11A of the casing 10A of the liquid-cooled casing, and the coolant circulation system is self-cooled. The liquid output end outputs a lower temperature coolant, and the first coolant inlet 22 of the first end 12 of the casing wall 11A of the casing 10A and the second coolant inlet 32 of the second end 13 of the casing wall 11A are respectively first. The spiral tube 20 and the second spiral tube 30 input cooling liquid, and the cooling liquid flows in the first spiral tube 20 and the second spiral tube 30, and passes through each of the spiral tube units 21, 31 and the second of the first spiral tube 20. Each of the spiral tube units 21, 31 of the spiral tube 30 exchanges heat with heat transferred to the shell wall 11A, so that the temperature of the housing 10A is lowered, and the coolant after the heat absorption in the first spiral tube 20 and the second spiral tube 30 are respectively The first coolant outlet 23 of the second end 13 of the casing wall 11A of the casing 10A and the second coolant outlet 33 of the first end 12 of the casing wall 11A are returned to the coolant circulation system for heat dissipation, and the low-temperature coolant after cooling and cooling is respectively separated. The first end 12 of the shell wall 11A opposite to the axial direction of the housing 10A of the liquid-cooled casing The coolant inlet 22, the second coolant inlet 32 of the second end 13 of the casing wall 11A are input to the first spiral pipe 20 and the second spiral pipe 30, whereby the coolant circulation cooling mechanism provides initiative to the motor or the generator High performance cooling and cooling.

In the foregoing, the liquid-cooled casing of the present invention comprises a first spiral tube 20 and a second spiral tube 30 which are circumferentially spiraled in the casing wall 11A of the casing 10A to form a double-spiral coolant flow passage for introducing the flow. The coolant is carried away by the heat generated by the operation of the motor or the generator, and the liquid-cooled casing further utilizes the first coolant inlet 22 of the first spiral tube 20 of the first end 12 of the casing wall 11A of the casing 10A, The second coolant inlet 32 of the second spiral tube 30 of the second end 13 of the shell wall 11A receives the coolant, and the heat exchanged coolant is again respectively from the first coolant outlet 23 of the second end 13 of the shell wall 11A, the shell wall The second coolant outlet 33 of the first end 12 of the 11A flows out, that is, the first coolant inlet 22 that inputs the lower temperature coolant and the second coolant outlet 33 that outputs the higher temperature coolant after the heat exchange are located at the shell wall 11A. The first end 12, the second coolant inlet 32 inputting the lower temperature coolant and the first coolant outlet 23 of the higher temperature coolant after the heat exchange are located at the second end 13 of the shell wall 11A, and then coupled with the first spiral tube The spiral tube units 21, 31 of 20 are staggered with the spiral tube units 21, 31 of the second spiral tube 30 So that the overall temperature of the liquid-cooled casing does not accumulate heat at either end of the casing 10A due to the flow direction of the coolant, and the double helix provided by the coolant in the first spiral pipe 20 and the second spiral pipe 30 of the casing 10A. The temperature difference between the input position, the output position, and the middle section of the coolant flow path in the coolant flow path is small, so that the temperature of the internal components of the motor or the generator is more balanced, and stable operation is possible.

The creator further uses a liquid-cooled casing with a single-screw coolant flow path and a liquid-cooled casing with a double-spiral coolant flow path to be used in a motor for verification test, in which room temperature water is used. (27 ° C) As a cooling liquid, the diameter of the tube of the spiral tube was 16 mm, and the motor operation condition was set to 30 kW and the energy loss was 2863 W for steady-state analysis. The test results are shown in the following table:         <TABLE border="1" borderColor="#000000" width="_0001"><TBODY><tr><td> Runner Type</td><td> Coolant Inlet Flow Rate</td><td> Cooling Temperature at the outlet end of the liquid </td><td> Maximum coil winding temperature of the motor stator (°C) </td></tr><tr><td> Single spiral coolant flow passage </td><td> 0.4m /sec </td><td> 54°C </td><td> 78.1°C </td></tr><tr><td> Single spiral coolant flow channel</td><td> 0.6m/ Sec </td><td> 48°C </td><td> 74.3°C </td></tr><tr><td> Double helix coolant flow channel</td><td> 0.4m/sec </td><td> 41°C </td><td> 70.6°C </td></tr><tr><td> Double helix coolant flow channel</td><td> 0.6m/sec < /td><td> 37.7°C </td><td> 68°C </td></tr></TBODY></TABLE>

It can be seen from the above test result list that the liquid-cooled casing with the double-spiral coolant flow channel can reduce the temperature of the coolant outlet end by 13 ° C under the condition that the coolant inlet flow rate is 0.4 m/sec. The maximum temperature of the coil winding of the motor stator is reduced by 7.5 °C. At a coolant inlet flow rate of 0.6 m/sec, the liquid-cooled casing with a double-spiral coolant flow path reduces the temperature at the outlet end of the coolant by 10.3 °C, and the maximum coil winding temperature of the motor stator is reduced by 6.3 °C. It is thus proved that the creation of a liquid-cooled casing with a double-spiral coolant flow channel can effectively provide excellent cooling performance.

10A, 10B, 10C‧‧‧ housing
100‧‧‧ center axis
11A, 11B, 11C‧‧‧ shell wall
12‧‧‧ first end
13‧‧‧ second end
14‧‧‧Axis hole
15A, 15B, 15C‧‧‧ inner shell
16A, 16B, 16C‧‧‧ Shell
161C‧‧‧Half shell
17A, 17B, 17C‧‧‧ spiral groove
171C‧‧‧ inner semi-spiral groove
172C‧‧‧ outer semi-spiral groove
20‧‧‧First spiral tube
21‧‧‧Spiral tube unit
22‧‧‧First coolant inlet
23‧‧‧First coolant outlet
30‧‧‧second spiral tube
31‧‧‧Spiral tube unit
32‧‧‧Second coolant inlet
33‧‧‧Second coolant outlet

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view showing a first preferred embodiment of a liquid-cooled casing having a double-spiral coolant flow path. 2 is a perspective view of a second preferred embodiment of the liquid-cooled casing having a double-spiral coolant flow path. Figure 3 is a side cross-sectional view showing the first preferred embodiment of the liquid-cooled casing having the double-spiral coolant flow path shown in Figure 1. Figure 4 is a side cross-sectional view showing a second preferred embodiment of the liquid-cooled casing having the double-spiral coolant flow path shown in Figure 2. Figure 5 is a side cross-sectional view showing a third preferred embodiment of the liquid-cooled casing having a double-spiral coolant flow path. Fig. 6 is a schematic end plan view showing a fourth preferred embodiment of the liquid-cooled casing having a double-spiral coolant flow path. Figure 7 is a side cross-sectional view showing a fourth preferred embodiment of the liquid-cooled casing having the double-spiral coolant flow path shown in Figure 6.

10A‧‧‧shell

100‧‧‧ center axis

11A‧‧‧ Shell wall

12‧‧‧ first end

13‧‧‧ second end

14‧‧‧Axis hole

17A‧‧‧Spiral groove

20‧‧‧First spiral tube

21‧‧‧Spiral tube unit

22‧‧‧First coolant inlet

23‧‧‧First coolant outlet

30‧‧‧second spiral tube

31‧‧‧Spiral tube unit

32‧‧‧Second coolant inlet

33‧‧‧Second coolant outlet

Claims (7)

A liquid-cooled casing having a double-screw coolant flow path, comprising: a casing comprising a casing wall defining a central axis, wherein the casing wall defines a central wall extending through the casing wall a shaft hole, the opposite ends of the shell wall along the central axis are respectively a first end and a second end; a first spiral tube is disposed inside the shell wall of the shell, the first spiral tube comprises a majority a first spiral tube unit, wherein the plurality of first spiral tube units are continuously spirally wound with respect to the central axis according to a spiral radius and a spiral lead, the first spiral tube having a first end extending beyond the first end of the shell wall a first coolant inlet, the first spiral tube has a first coolant outlet extending beyond the second end of the casing wall; and a second coil disposed inside the casing wall of the casing, the second spiral The tube includes a plurality of second spiral tube units, the plurality of second spiral tube units are continuously spirally wound with respect to the central axis according to the spiral radius and the spiral lead, and the second spiral tube unit of the second spiral tube and the second spiral tube unit First spiral of a spiral tube Derangement unit, the second coil having a second coolant outlet of the first end of the outer wall of the hatched stretched, the second coil having a second coolant inlet of the second end of the outer wall of the stretched hatched. The liquid-cooled casing having a double-spiral coolant flow path according to claim 1, wherein the first coolant inlet of the first coil and the second coolant outlet of the second coil are from the shell wall The first end is radially protruded from the same side, and the first coolant outlet of the first spiral tube and the second coolant inlet of the second spiral tube extend radially from the inside of the second end of the shell wall toward the side. . The liquid-cooled casing having a double-spiral coolant flow path according to claim 1, wherein the first coolant inlet of the first coil and the second coolant outlet of the second coil are from the shell wall The first end protrudes outward in different radial directions, and the first coolant outlet of the first spiral tube and the second coolant inlet of the second spiral tube are respectively radially from the inside of the second end of the shell wall The opposite sides protrude. The liquid-cooled casing having a double-spiral coolant flow path according to claim 1, wherein the first coolant inlet of the first coil and the second coolant outlet of the second coil are from the shell wall The first end internally protrudes in the direction of the central axis, and the first coolant outlet of the first spiral tube and the second coolant inlet of the second coil extend from the inside of the second end of the casing wall in the direction of the central axis. The liquid-cooled casing having a double-spiral coolant flow path according to any one of claims 1 to 4, wherein the casing wall comprises an inner casing portion and a casing provided on an outer peripheral surface of the inner casing portion. a second spiral groove is formed in the outer wall surface of the inner casing portion, the first spiral tube and the second spiral tube are disposed in the two spiral grooves, and the first spiral tube is in contact with the second spiral tube Shell and outer casing. The liquid-cooled casing having a double-spiral coolant flow path according to any one of claims 1 to 4, wherein the casing wall comprises an inner casing portion and a casing provided on an outer peripheral surface of the inner casing portion. a portion of the inner casing portion forming a spiral groove toward the outer wall surface of the outer casing portion, wherein the first spiral tube and the second spiral tube are respectively disposed in the two spiral grooves, and the first spiral tube is in contact with the second spiral tube Inner shell portion and outer shell portion. The liquid-cooled casing having a double-spiral coolant flow path according to any one of claims 1 to 4, wherein the casing wall comprises an inner casing portion and a casing provided on an outer peripheral surface of the inner casing portion. The inner casing portion forms two sets of inner semi-spiral grooves toward the outer wall surface of the outer casing portion, the outer casing portion is composed of two half-shell portions which are oppositely combined, and the outer casing portion forms two sets of outer half-helix toward the inner wall surface of the inner casing portion. a groove, the two sets of outer semi-spiral grooves corresponding to the two sets of inner semi-spiral grooves and synthesizing two spiral grooves, wherein the first spiral tube and the second spiral tube are respectively disposed in the two spiral grooves, the first spiral tube The inner spiral portion and the outer casing portion are in contact with the second spiral tube.