Liquid-cooled core assembly for a linear motor and a linear motor including such a core assembly - Patents.com

Abstract

To provide a liquid-cooled core assembly for a linear motor and a linear motor comprising the core assembly.SOLUTION: The present invention relates to a liquid-cooled core assembly (10) for a linear motor, comprising an iron-core (12) having: a middle part (12a); teeth (15) extending from two opposite sides of the middle part and forming slots (16) therebetween; coils wound around the teeth; axial cooling-fluid passageways (18) extending across the middle part (12a); and cooling conduits (30) arranged inside the passageways (18). The core assembly (10) further comprises a cooling arrangement comprising a liquid supplying part (20) and a liquid collecting part (40) mounted on respective two other opposite sides of the iron-core (12). The liquid supplying and collecting parts (20, 40) are in fluid communication with the cooling conduits (30). An inlet connector (70) is in fluid communication with the liquid supplying part (20) and an outlet connector (72) is in fluid communication with the liquid collecting part (40).SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001]

[0001] The present invention relates to a liquid-cooled core assembly for a linear motor having an iron core made from a single lamination stack. The present invention also relates to a linear motor having a liquid-cooled core assembly. [Background technology]

[0002] Liquid-cooled core assemblies as main parts / motors for linear motors are well known in the art and many solutions have already been proposed.

[0003] For example, US Patent Application Publication No. 2019131831 discloses a core assembly for a linear motor, comprising a first core and a second core, each having two opposing sides provided with a slot and a linear groove, respectively. The sides of the first and second cores with linear grooves are attached to each other to form a plurality of parallel channels, inside which portions of two cooling serpentines are disposed. However, the core assembly is difficult to manufacture, thereby having a negative impact on the overall cost of the linear motor.

[0003]

[0004] EP1120890 discloses a core assembly for a linear motor comprising a single lamination stack with slots on both sides for coils. The linear motor comprises a top core cover having a longitudinal groove in the centre of its upper surface. A U-shaped cooling pipe for passing a coolant is housed in the groove, thereby cooling only the upper part of the lamination stack and the user interface. The uneven cooling of the lamination stack has the disadvantage of reducing the force-to-ground area ratio of the linear motor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent Application Publication No. 2019131831 [Patent Document 2] EP1120890 Summary of the Invention [Problem to be solved by the invention]

[0005] SUMMARY OF THE PRESENT EMBODIMENTS

[0005] It is therefore an object of the present invention to provide a liquid-cooled core assembly for a linear motor that is easy to manufacture and cost effective.

[0006] Another object of the present invention is to provide a liquid cooled core assembly for a linear motor having an improved force to ground area ratio over known solutions.

[0006]

[0007] Another object of the present invention is to provide a liquid cooled core assembly for a linear motor with efficient and uniform cooling of both the inside of the core and at the customer interface.

[0008] It is a further object of the present invention to provide a liquid cooled core assembly with a customer interface that can be easily adapted to accommodate the configuration of a permanent magnet assembly provided by a customer.

[0007]

[0009] It is a still further object of the present invention to provide a linear motor which includes a liquid cooled core assembly slidably mounted to a permanent magnet assembly. [Means for solving the problem]

[0008]

[0010] These objectives are: an iron core having a central portion, teeth extending from two opposite sides of the central portion and forming slots therebetween, a coil wound about the teeth, an axial cooling fluid passage extending across the central portion, and a cooling conduit mounted inside said passage; a cooling device comprising a liquid supply and a liquid collection mounted on two other opposite sides of each of said iron cores, both of said liquid supply and liquid collection being in fluid communication with said cooling conduit; an inlet fitting in fluid communication with a liquid supply and an outlet fitting in fluid communication with a liquid collection; This is accomplished by a liquid cooled core assembly for a linear motor comprising:

[0009]

[0011] In one embodiment, the liquid supply comprises a liquid supply conduit and a channel in fluid communication with the liquid supply conduit and sealingly connected to a first end portion of each conduit, and the liquid collection comprises a liquid collection conduit and a channel in fluid communication with the liquid collection conduit and sealingly connected to a second end portion of each said conduit.

[0010]

[0012] In one embodiment, the first and second end portions of each conduit project from said two other opposing sides inwardly of end portions of corresponding channels of the respective liquid supply and liquid collection portions.

[0011]

[0013] In one embodiment, the end portions of each channel of the liquid supply and liquid collection sections are provided with a seal receiving portion, inside which a seal, preferably an O-ring, is fitted around the aforementioned first and second end portions of each conduit.

[0012]

[0014] In one embodiment, the core further includes an axial through hole extending across the center thereof alternating with the cooling fluid passages.

[0015] In one embodiment, the central axes of said passages and said through-holes are aligned in a plane across a central portion of the core, said plane being located substantially equidistant between said two opposing sides of the central portion.

[0013]

[0016] In one embodiment, each of the axial cooling fluid passages and through holes is aligned with two slots located respectively on one and the other of said two opposing sides of the central portion.

[0014]

[0017] In one embodiment, each of the axial cooling fluid passages and through holes is aligned with two slots located respectively on one and the other of said two opposing sides of the central portion.

[0015]

[0018] In one embodiment, the liquid supply and liquid collection are assembled to the iron core by screws.

[0019] In one embodiment, the liquid supply comprises a threaded hole and the liquid collection comprises a through hole. A screw extends along each through hole of the liquid collection and the through hole of the iron core. An end portion of the screw is screwed into a corresponding threaded hole of the liquid supply.

[0016]

[0020] In one embodiment, a threaded sleeve is disposed around a section of the threads that spans a liquid collection conduit of the liquid collector to seal said section from the liquid collection conduit.

[0021] In one embodiment, each of the liquid supply section and the liquid collection section has a T-shaped cross-section that forms a compartment with each of the two other opposing sides of the iron core to receive a portion of the coil, and this T-shaped cross-section is constant along the entire length of the liquid supply section and the liquid collection section.

[0017]

[0022] In one embodiment, an inlet tube is attached to the inside of the liquid supply conduit, the inlet tube is in fluid communication with the inlet fitting and extends along a portion of the liquid supply conduit such that an end portion of the inlet tube is located between one-third and two-thirds of the length of the supply conduit, preferably in the middle of the length of the supply conduit.

[0018]

[0023] In one embodiment, the liquid-cooled core assembly includes first and second mounting portions assembled to respective first and second outer portions of the iron core and respective first and second outer portions of the liquid supply and liquid collection portions, the inlet and outlet fittings being mounted in one of the first and second mounting portions.

[0019]

[0024] In one embodiment, the inlet fitting is located as close as possible to the customer interface to ensure that the interface remains at ambient temperature.

[0025] In one embodiment, a cable gland for electrical connection of the coil is attached to a fitting that includes an inlet fitting and an outlet fitting.

[0020]

[0026] Another aspect of the present invention relates to a linear motor including the above-described liquid-cooled core assembly slidably mounted to a permanent magnet assembly.

[0027] The invention will be better understood from the description of some embodiments thereof, given by way of example and illustrated in the drawings. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is an exploded perspective view of an iron core for a linear motor made from a single lamination stack and cooling tubes adapted to fit inside the axial cooling fluid passages of the iron core according to one embodiment. [Diagram 2] FIG. 2 is a view similar to FIG. 1 with the cooling tubes mounted inside their respective cooling fluid passages. [Diagram 3] FIG. 3 is a top view of the iron core of FIG. 2, without the cooling tubes. [Figure 4] FIG. 4 is a view similar to FIG. 3 according to another embodiment. [Diagram 5] FIG. 2 illustrates a top perspective view of a liquid supply according to one embodiment. [Figure 6] FIG. 6 is a bottom perspective view of the liquid supply unit of FIG. 5. [Figure 7] 1 is a cross-sectional view of a liquid supply or liquid collection section. [Figure 8] FIG. 13 is an enlarged cross-sectional view of an end portion of a cooling tube sealingly connected to a corresponding channel of a liquid supply. [Figure 9] FIG. 13 is an enlarged cross-sectional view of an end portion of a cooling tube sealingly connected to a corresponding channel in a liquid collection portion. [Figure 10] FIG. 2 is a partial perspective view of a liquid-cooled core assembly. [Figure 11] 1 illustrates a cross-sectional view of a liquid-cooled core assembly according to one embodiment. [Figure 12] 4 is a partial cross-sectional view of a liquid-cooled core assembly according to another embodiment. [Figure 13] Figure 13a is a top view of a liquid-cooled core assembly with a different configuration of a connection part of a customer interface for connection to a permanent magnet assembly, Figure 13b is a top view of a liquid-cooled core assembly with a different configuration of a connection part of a customer interface for connection to a permanent magnet assembly, and Figure 13c is a top view of a liquid-cooled core assembly with a different configuration of a connection part of a customer interface for connection to a permanent magnet assembly. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022]

[0028] In the context of the present invention, the liquid-cooled core assembly should be understood as a motor, moving part, slider or glider configured to be slidably mounted to a permanent magnet assembly of a linear motor. Furthermore, in the context of the present invention, the term "customer interface" should be understood as the part of the core assembly that is to be slidably mounted to the permanent magnet assembly.

[0023]

[0029] 1-4 and 10, the liquid cooled core assembly 10 includes an iron core 12 made of a lamination stack. The magnetic iron core 12 includes a central portion 12a extending between two outer portions 13a, 13b of the iron core 12. Teeth 16 extend from two opposing sides of the central portion 12a along two longitudinal sides 14a, 14b of the iron core 12. Slots 17 formed between the teeth 16 on one side of the central portion 12a are aligned with slots 17 formed between the teeth 16 on the opposing side of the central portion 12a.

[0024]

[0030] Axial cooling fluid passages 18 and through holes 19 are drilled in the core 12. The through holes 19 extend across the central portion 12a of the core 12 in alternating fashion with the axial cooling fluid passages 18. The central axes of the passages 18 and through holes 19 are preferably aligned in a plane that spans the central portion 12a of the core 12 along the length of the core 12, the plane being substantially equidistant between two opposing sides of the central portion 12a from which the teeth 16 extend.

[0025]

[0031] Each of the cooling fluid passages 18 and through holes 19 is aligned with two corresponding slots 17 located on one and the other of the aforementioned two opposing sides of the central portion 12a. The passages and through holes 18, 19 may also be aligned with two corresponding opposing teeth 16 according to the embodiment shown in FIG. 4, however, this configuration is not optimal for attraction force cancellation since it increases magnetic stray flux circulating between adjacent teeth 16.

[0026]

[0032] As shown in detail in Figures 1 and 2, cooling conduits, preferably in the form of tubes 30, are inserted into the cooling fluid passages 18. The use of tubes ensures that no fluid leakage occurs between the layers of the stack, which could cause corrosion. The core 12 is heated prior to the insertion of the cooling tubes 30 in order to increase the diameter of the passages 18. This ensures very tight mechanical tolerances and optimal heat transfer between the lamination stack and the cooling tubes 30 when the diameter of the passages 18 returns to its initial size at ambient temperature. Each cooling tube 30 comprises first and second end portions 30a, 30b protruding respectively from the top side 15a and bottom side 15b of the central portion 12a of the core 12.

[0027]

[0033] 10, the liquid cooled core assembly 10 comprises a cooling system including a liquid supply 20 and a liquid collection 40 attached to respective top and bottom sides 15a, 15b of the central portion 12a of the iron core 12. Both the liquid supply 20 and the liquid collection 40 are manufactured as aluminum extrusions that are cut to the length of the motor.

[0028]

[0034] 5, 6 and 7, each of the liquid supply 20 and liquid collection 40 includes a liquid supply conduit 24 and a liquid collection conduit 44 (FIGS. 7 and 11), respectively, that extends through the respective supply 20 and collection 40 along their entire length. The cross-sections of the liquid supply conduit 24 and liquid collection conduit 44 are preferably constant along their entire length.

[0029]

[0035] The liquid supply conduit 24 comprises, for example, a partial upper cylindrical portion 24a and a lower portion 24b that extends across the width of the liquid supply 40. The shape of the lower portion 24b has the advantage of providing a cooling fluid reservoir that reduces as much as possible the pressure loss due to fluid flow in the liquid supply conduit 24. The shape of the liquid collection conduit 44 is preferably identical to that of the liquid supply conduit 24 in order to simplify the manufacturing operations of the liquid supply 20 and the liquid collection 40 by using the same extrusion dies for them.

[0030]

[0036] Each of the liquid supply 20 and liquid collection 40 includes a channel 26, 46 in fluid communication with a respective liquid supply conduit 24 and liquid collection conduit 44. As shown in detail in FIG. 10 , an end portion 27 of each channel 26 of the liquid supply 20 is sealingly connected to a first end portion 30a of a respective cooling tube 30, while an end portion 27 of each channel 46 of the liquid collection 40 is sealingly connected to a second end portion 30b of a respective cooling tube 30.

[0031]

[0037] More specifically, with reference to Figures 7 and 8, the end portion 27 of each channel 26 of the liquid supply 20 includes a closure receiving portion 27a and a tube end receiving portion 27b. The closure receiving portion 27a may be cylindrical or preferably has a rectangular machined surface as shown in Figure 6. Similarly, the end portion 47 of each channel 46 of the liquid collection 20, as shown in Figure 10, includes a closure receiving portion and a tube end receiving portion as shown in Figure 9.

[0032]

[0038] As best seen in Figures 11 and 12, the inlet tube 22 is attached inside the partial upper cylindrical section 24a of the liquid supply conduit 24. The inlet tube 22 is in fluid communication with the inlet fitting 70 and extends along a portion of the liquid supply conduit 24 such that the end portion 22a of the inlet tube 22 is located between one-third and two-thirds of the length of the supply conduit 24. The end portion 22a of the inlet tube 22 is preferably located near the middle of the length of the supply conduit 24. The length of the inlet tube 22 is adapted to the size of the liquid-cooled core assembly 10, as shown in Figure 12.

[0033]

[0039] The inlet tube 22 ensures that the cooling liquid flows into the lower portion 24b of the liquid supply conduit 24 at the center of the length of the liquid supply conduit 24, which extends along the length of the linear motor liquid-cooled core assembly 10, thereby avoiding pressure and temperature gradients inside the core assembly.

[0034]

[0040] 11, the liquid supply part 20 and the liquid collection part 40 are assembled to the respective top side 15a and bottom side 15b of the iron core 12 by means of screws 50. In this regard, the liquid supply part 20 includes a threaded hole 28, while the liquid collection part 40 includes a through hole 48.

[0035]

[0041] The screw 50 extends along the respective through hole 48 of the liquid collection portion 40 and the through hole 19 of the core 12, and an end portion of the screw 50 is threaded into a corresponding threaded hole 28 of the liquid supply portion 20. A threaded sleeve 49 is disposed around the section of the screw 50 that spans the liquid collection conduit 44 of the liquid collection portion 40 to seal the screw 50 from the liquid collection portion.

[0036]

[0042] Each of the liquid supply portion 20 and the liquid collection portion 40 has a T-shaped cross-section forming a compartment with each of the two other opposing sides of the core 12 for receiving an end turn of a coil (not shown).

[0037]

[0043] 10, first and second mounting parts 60a, 60b are assembled to the iron core 12 and to first and second outer parts of the liquid supply part 20 and the liquid collection part 40, respectively. Each of the first and second mounting parts 60a, 60b is connected to the outer parts of the liquid supply part 20 and the liquid collection part 40, respectively, by means of a self-tapping screw adjusted in a corresponding tubular portion of a longitudinal slot 29 provided in the liquid supply part 20 and the liquid collection part 40, as shown in FIGS. 5 to 7.

[0038]

[0044] One mounting part 60a comprises a cylindrical or threaded portion 62, 64 for receiving fittings, in which an inlet fitting 70 and an outlet fitting 72 of the cooling device are mounted, as shown in Figure 11. The inlet fitting 70 is located as close as possible to the customer interface 21 to ensure that the interface remains at ambient temperature. An additional cylindrical or threaded portion 66 is provided on the mounting part 60a, in which a cable gland 74 is mounted for the electrical connection of a coil (not shown) wound around the teeth 16 of the core 12.

[0039]

[0045] For example, as shown in FIG. 11, sealing grooves 68 are disposed on the first and second mounting portions 60a, 60b around both end portions of the liquid supply conduit 24 and the liquid collection conduit 44 of the respective supply portion 20 and collection portion 40 to avoid any leakage.

[0040]

[0046] For example, as shown in FIG. 5, the customer interface 21 includes threaded holes 21a for assembling the liquid-cooled core assembly 10 to a permanent magnet assembly of a linear motor. The customer interface can be easily adapted to conform to the configuration of a customer's permanent magnet assembly through minor modifications. For example, the pitch, size, and / or number of the threaded holes 21a on the customer interface 21 can be changed, as shown in FIGS. 13a, 13b, and 13c. [Explanation of symbols]

[0041] 10 Liquid-cooled core assembly 12 Magnetic core 12a central part 13a, 13b outer part 14a, 14b Longitudinal side 15a Top side 15b Bottom side 16 teeth 17 Slots 18 Cooling fluid passage 19 Through Hole 20 Liquid supply section 21 Customer Interface 21a screw hole 22 Inlet pipe 22a End part 24 Liquid supply conduit 24a Partial cylindrical section 24b Lower part 26 Channels 27 End part 27a Sealing tool receiving part 27b Pipe end receiving part 28 screw holes 29 Longitudinal Slot 30 Cooling pipe 30a, 30b end part 32 O-ring 40 Liquid collection section 44 Liquid collection conduit 46 Channels 47 End part 48 Through Hole 49 Screw sleeve 50 Screw 60a First mounting portion 60b Second mounting portion 62, 64 Connector receiving portion 66 Cable gland receiving part 66 68 Sealing Ring 70 Inlet fitting 72 Outlet fitting 74 Cable Gland

Claims

1. A liquid-cooled core assembly (10) for a linear motor, comprising: an iron core (12) having a central portion (12a), teeth (16) extending from two opposite sides of the central portion (12a) and forming slots (17) therebetween, a coil wound around the teeth (16), an axial cooling fluid passage (18) extending across the central portion (12a), and a cooling conduit (30) disposed inside the passage (18); a cooling device comprising a liquid supply (20) and a liquid collection (40) attached to two other opposite sides of each of said iron cores (12), said liquid supply and liquid collection (20, 40) being in fluid communication with said cooling conduit (30); an inlet fitting (70) in fluid communication with said liquid supply (20) and an outlet fitting (72) in fluid communication with said liquid collection portion (40); Equipped with the liquid supply portion (20) comprises a liquid supply conduit (24) and a channel (26) in fluid communication with the liquid supply conduit (24) and sealingly connected to a first end portion (30a) of each of the conduits (30); the liquid collection portion (40) comprises a liquid collection conduit (44) and a channel (46) in fluid communication with the liquid collection conduit (44) and sealingly connected to a second end portion (30b) of each of the conduits (30); the iron core (12) further comprises an axial through hole (19) extending across the central portion (12a) in alternating relation with the cooling fluid passages (18); The liquid supply and liquid collection parts (20, 40) are assembled to the iron core (12) by means of screws (50); The screw (50) extends along a through hole (19) of the iron core (12). A liquid-cooled core assembly (10).

2. 2. The liquid-cooled core assembly (10) of claim 1, wherein the first and second end portions (30a, 30b) of each conduit (30) protrude from their respective two other opposing sides into end portions (27, 47) of corresponding channels (26, 46) of the respective liquid supply and liquid collection portions (20, 40).

3. 3. The liquid-cooled core assembly (10) of claim 2, wherein the end portions (27, 47) comprise seal receiving portions (27a, 47a), inside which seals (32), preferably O-rings, are mounted around the first and second end portions (30a, 30b) of each conduit (30).

4. 2. The liquid-cooled core assembly (10) of claim 1, wherein the central axes of the passages (18) and the through holes (19) are aligned in a plane spanning the central portion (12a) of the iron core, the plane being located substantially equidistant between the two opposing sides of the central portion (12a).

5. 5. The liquid-cooled core assembly (10) of claim 1 or 4, wherein each of the passages (18) and the through holes (19) is aligned with two slots (16) respectively disposed on one and the other of the two opposing sides of the central portion (12a).

6. 2. The liquid-cooled core assembly (10) of claim 1, wherein the liquid supply portion (20) includes a threaded hole (28), the liquid collection portion (40) includes a through hole (48), the screws (50) extend along each through hole (48) of the liquid collection portion (40), and end portions of the screws (50) are threaded into the corresponding threaded holes (28) of the liquid supply portion (20).

7. 7. The liquid-cooled core assembly (10) of claim 6, wherein a threaded sleeve (49) is disposed around a section of the thread (50) that spans the liquid collection conduit (24) of the liquid collection section (40) to seal said section from the liquid collection conduit.

8. 8. The liquid-cooled core assembly (10) of claim 1, wherein each of the liquid supply and liquid collection sections (20, 40) has a T-shaped cross-section forming a compartment with each of the two other opposing sides of the iron core (12) to receive a portion of the coil.

9. 9. The liquid-cooled core assembly (10) according to any one of claims 1 to 8, wherein an inlet tube (22) is attached inside the liquid supply conduit (24), the inlet tube (22) is in fluid communication with the inlet fitting (70) and extends along a portion of the liquid supply conduit (24) such that an end portion (22a) of the inlet tube (22) is located between one-third and two-thirds of the length of the supply conduit (24), the end portion (22a) being preferably located in the middle of the length of the supply conduit.

10. 10. The liquid-cooled core assembly (10) according to any one of claims 1 to 9, comprising first and second mounting portions (60a, 60b) assembled to respective first and second outer portions of the iron core (12) and respective first and second outer portions of the liquid supply and liquid collection portions (20, 40), and the inlet and outlet fittings (70, 72) are mounted in one of the first and second mounting portions (60a, 60b).

11. 11. The liquid-cooled core assembly (10) of claim 10, wherein a cable gland (74) for electrical connection of the coil is attached to the mounting portion (60a) having the inlet and outlet fittings (70, 72).

12. A linear motor comprising a liquid-cooled core assembly (10) according to any one of claims 1 to 11 slidably mounted to a permanent magnet assembly.

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