A cooling flow channel structure for directional transportation of liquid and its processing method

Abstract

A cooling channel structure for liquid directional transportation and its processing method disclosed by the present invention, the cooling channel structure includes a microstructure with directional transportation, the microstructure with directional transportation includes a substrate, a microgroove structure, and several protrusions; the microgroove structure is arranged on the surface of the substrate along the liquid droplet transportation direction; the protrusions are located in the microgroove structure, and adjacent protrusions are stacked on top of each other. The processing method of the cooling channel structure for liquid directional transportation includes the following steps: Step 1, select the forming surface and polish the surface; Step 2, use a stamping forming punch to stamp and form the microgroove structure and the protrusions at the bottom of the groove on the substrate of the forming surface; Step 3, use a ploughing extrusion tool to cut off the connection between the protrusions at the bottom of the groove and the groove side wall, and trim the protrusions into duckbill-shaped inclined protrusions.

Description

Technical Field

[0001] The present invention belongs to the research fields of oil-cooled motors, bionic microstructures, and precision microfabrication, and particularly relates to a cooling channel structure for liquid directional transportation and a processing method thereof. Background Art

[0002] Liquid directional transportation refers to the unpowered continuous transportation of liquid relying on its own surface tension, Laplace pressure, etc. without external energy input. When a liquid is dropped on a solid surface, it presents a spreading or pinning state because the liquid is subjected to the same forces around. When the surface tension of the liquid is less than the surface energy of the solid, the liquid shows a spreading state around on the solid surface; if the surface tension of the liquid is greater than the surface energy of the solid, the liquid will stably stop on the solid surface, that is, when the liquid moves on the solid surface, it may be affected by the hysteresis effect, causing the liquid to be pinned on the solid surface and stop advancing. In order to reduce the hysteresis effect, an external force needs to be applied to give a stimulus to the solid surface to break the original balance of the liquid, so more and more responsive materials are used to construct intelligent surfaces to achieve the controllability of liquid movement on the solid surface.

[0003] Under the action of light, gravity, heat, electric field, and mechanical stretching, liquid can achieve directional transportation on the solid surface. In addition, with the in-depth research, scientists have designed the surface to have a certain structural gradient and utilized the Laplace pressure effect to achieve liquid directional movement. In short, through the surface tension gradient and Laplace pressure gradient, the directionally controllable liquid transportation is realized (Gao Xiangyu. Research on the directional wetting behavior of liquid on microstructured surfaces [D]. Beijing University of Chemical Technology, 2017.). It can be used not only in fields such as controllable microfluidics, drug delivery, new energy, and unpowered irrigation in agriculture, but also can achieve unpowered self-lubrication, and has broad application prospects in many mechanical engineering technology fields.

[0004] Currently, surfaces with liquid directional transportation functions are mostly realized by surface chemical modification to construct surfaces with gradient wettability. In 2007, Han Yanchun et al. inlaid hydrophilic mica with a shape gradient on the surface of a hydrophobic wax substrate or a low-density polyethylene substrate. And by changing the pattern shape of this area, it was found that the surface with a shape gradient can better realize liquid movement, and even when the structure is tilted, the water droplet can climb upward along this area. In 2018, Liao Guanglan et al. utilized the wedge-shaped basic unit with a gradient structure to generate a Laplace pressure difference on the flow channel, spontaneously driving the fluid to transport directionally on the flow channel and collecting it along the continuous fractal structure, but did not describe the processing method of this structure. In 2019, Duan Zhongfeng et al. designed conical fibers with a concave structure, and utilized the synergistic effect of the Laplace pressure generated by the conical structure gradient and the capillary force generated by the concave structure to achieve ultra-fast directional transportation of liquid.

[0005] There are problems in surface modification processing in terms of functions, such as high processing costs, environmental pollution caused by surface modifiers, and poor surface environmental endurance after modification; and most of the modified materials are fiber materials, it is difficult to modify metal materials, machining methods are rarely used in the modification of the directional transportation structure, and mass production cannot be carried out, etc. Summary of the Invention

[0006] Aiming at the deficiencies existing in the prior art, the object of the present invention is to provide a micro-structure for liquid transportation in a cooling flow channel for an oil-cooled motor and a processing method thereof.

[0007] The present invention is realized by at least one of the following technical solutions.

[0008] A cooling flow channel structure for liquid directional transportation includes a microstructure with directional transportation. The microstructure with directional transportation includes a substrate, a micro-groove structure, and a number of protrusions; the micro-groove structure is arranged on the surface of the substrate along the liquid droplet transportation direction; the number of protrusions is located in the micro-groove structure, and adjacent protrusions are stacked on top of each other.

[0009] Preferably, the micro-groove structure is a micro-groove array structure, and the micro-groove array structure is parallel to the liquid droplet directional transportation direction.

[0010] Preferably, the depth of the micro-groove array structure is 50 - 150 μm, the width of each groove is 100 - 950 μm, and the distance between each groove is 100 - 1000 μm.

[0011] Preferably, a number of protrusions are evenly distributed at the bottom of each groove. The protrusions are inclined columns, forming a stacked structure.

[0012] Preferably, the cross-section of each protrusion is duckbill-shaped, forming a duckbill-shaped protrusion.

[0013] Preferably, the radius of the arc of the cross-section of the duckbill-shaped protrusion is 10 - 500 μm, the angle between the duckbill-shaped protrusion and the groove wall surface is 0 - 30°, and the distance between the duckbill-shaped protrusions is 30 - 150 μm.

[0014] 11. Preferably, the inclination angle of each protrusion is 10 - 90°, the height is 50 - 400 μm, and the width is 80 - 900 μm.

[0015] A processing method for the cooling flow channel structure for liquid directional transportation as described above includes the following steps:

[0016] Step 1: Select a forming surface and polish the surface;

[0017] Step 2: Use an imprinting forming punch to imprint and form a micro-groove structure and protrusions at the bottom of the groove on the substrate of the forming surface;

[0018] Step 3: Use a plowing and extrusion tool to cut off the connection between the protrusion at the bottom of the groove and the side wall of the groove, and trim the protrusion into a duckbill-shaped inclined protrusion.

[0019] Preferably, the surface flatness after grinding is less than 0.01 mm; the embossing pressure is 1-50 MPa; the plowing and extrusion process is one-way cutting, the return tool does not contact the workpiece, and the cutting speed is 1-300 mm / s.

[0020] Preferably, the matrix material comprises copper.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) Imprinting and forming processing can quickly, efficiently and over a large area to produce high-quality, regular and neatly shaped microstructures with high shape accuracy;

[0023] (2) The inclination angle of the duckbill protrusion and the angle between it and the groove wall together provide the power for directional transport of the liquid, and the liquid transport speed is fast;

[0024] (3) Compared with other surface modification processing methods, it has higher environmental resistance and lower processing cost;

[0025] (4) The present invention is different from the conventional smooth motor cooling channel and can prevent the cooling oil from flowing back after the oil pump stops;

[0026] (5) Directional transport flow channel Directional transport of cooling medium can effectively reduce the cooling oil flow rate and inlet pressure, greatly reduce costs and generate better economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic diagram of the microstructure of directional transport in this embodiment;

[0028] Figure 2 is a schematic structural diagram of the microstructure of directional transport in this embodiment;

[0029] Figure 3 is a schematic diagram of the geometric structure and cross section of the microstructure for directional transport in this embodiment;

[0030] Figure 4 It is a schematic diagram of the embossing molding process of this embodiment;

[0031] Figure 5 Schematic diagram of the plowing and extrusion process of this embodiment;

[0032] Among them, 1 is the water inlet of the cooling channel, 2 is the cooling channel, 3 is the water outlet of the cooling channel, 4 is the substrate, 5 is the micro-groove array, 6 is the duckbill-shaped protrusion, 7 is the embossing forming punch, 8 is the sheet substrate after embossing forming, and 9 is the plowing extrusion tool. Detailed implementation manners

[0033] To better understand the present invention, the following further describes the present invention in conjunction with the drawings and embodiments. However, the scope of protection required by the present invention is not limited to the scope shown in the embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

[0034] This part will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the drawings. The function of the drawings is to supplement the description in the text part of the specification, enabling people to intuitively and vividly understand each technical feature and the overall technical solution of the present invention. However, it should not be construed as a limitation on the protection scope of the present invention.

[0035] In the description of the present invention, it should be understood that for the orientation description, such as the orientation or positional relationship indicated by up, down, front, back, left, right, etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present invention.

[0036] In the description of the present invention, the meaning of several is one or more, the meaning of multiple is more than two, greater than, less than, exceeding, etc. are understood as not including the present number, and above, below, within, etc. are understood as including the present number. If the first and second are described only for the purpose of distinguishing technical features, they should not be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0037] In the description of the present invention, unless otherwise clearly defined, words such as setting, installing, and connecting should be understood in a broad sense. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0038] Embodiment 1:

[0039] A cooling channel structure for liquid directional transportation, including a microstructure with directional transportation. The microstructure with directional transportation includes a substrate and a micro-groove structure; the micro-groove structure is a micro-groove array structure, and the micro-groove structure is uniformly arranged on the surface of the substrate along the liquid droplet transportation direction;

[0040] The micro-groove structure is a micro-groove array structure, and the micro-groove array structure is parallel to the liquid droplet directional transportation direction.

[0041] A number of protrusions are evenly distributed at the bottom of each groove. The protrusions are inclined columns, and adjacent protrusions overlap each other.

[0042] The depth of the micro-groove array structure is 50 - 150 μm, the width of each groove is 100 - 950 μm, and the spacing between the grooves is 100 - 1000 μm.

[0043] Example 2:

[0044] As Figure 1 、 Figure 2 shown, a cooling flow channel structure for liquid directional transportation includes a microstructure with directional transportation. The microstructure with directional transportation includes a substrate 4 and a micro-groove structure. The micro-groove structure is a micro-groove array structure 5, and the micro-groove structure is evenly arranged on the surface of the substrate 4 along the liquid droplet transportation direction;

[0045] The micro-groove structure is a micro-groove array structure 5, and the micro-groove array structure 5 is parallel to the liquid droplet directional transportation direction.

[0046] The depth of the micro-groove array structure 5 is 50 - 150 μm, the width of each groove is 100 - 950 μm, and the spacing between the grooves is 100 - 1000 μm.

[0047] A number of protrusions are evenly distributed at the bottom of each groove. The cross-section of each protrusion is duckbill-shaped, forming a duckbill-shaped protrusion 6, and adjacent protrusions overlap each other.

[0048] The duckbill-shaped structure has a certain structural gradient, and the Laplace pressure generated by the structural gradient causes the liquid to move spontaneously in the micro-groove structure.

[0049] As a preferred embodiment, as Figure 3 shown, the radius r of the circular arc of the cross-section of the duckbill-shaped protrusion 6 is 10 - 500 μm, the included angle α between the duckbill-shaped protrusion 6 and the groove wall surface is 0 - 30°, and the spacing d between the duckbill-shaped protrusions is 30 - 150 μm.

[0050] The inclination angle β of each duckbill-shaped protrusion 6 is 10 - 90°, the height h is 50 - 400 μm, and the width b is 80 - 900 μm.

[0051] As a preferred embodiment, the microstructure with directional transportation can be arranged in the cooling flow channel of an oil-cooled motor.

[0052] As Figure 1As shown, the cooling flow channel of the oil-cooled motor includes a cooling flow channel water inlet 1 and a cooling flow channel water outlet 3. The cooling flow channel water inlet 1 and the cooling flow channel water outlet 3 are connected by a cooling flow channel 2. Figure 1 A microstructure with directional transportation is arranged on the cooling flow channel 2.

[0053] As a preferred embodiment, the matrix material is copper, with a material size of 30x30x3 mm. First, the surface of the copper sheet is polished successively with 100, 220, 500, and 800-mesh sandpapers to make its flatness less than 0.01 mm.

[0054] The processing method for the cooling flow channel structure with liquid directional transportation includes the following steps:

[0055] Step 1: Select the forming surface and polish the surface; the flatness of the polished surface should be less than 0.01 mm.

[0056] Step 2: As Figure 4 shown, use a stamping forming punch 7 to stamp a micro-groove array and a protrusion at the bottom of the groove on the metal matrix 4 to obtain a sheet matrix 8 after stamping; the stamping forming pressure is 1 - 50 Mpa; the equipment used for stamping forming is a hydraulic press, a die press, or a bench vice and other pressure equipment.

[0057] Step 3: Use a ploughing and extrusion tool 9 to cut off the connection between the protrusion at the bottom of the groove and the groove side wall, and trim the protrusion into a duckbill-shaped inclined protrusion. The ploughing and extrusion process is one-way cutting, and the return tool does not contact the workpiece. The cutting speed is 1 - 300 mm / s.

[0058] Use a stamping forming punch to perform stamping forming on a hot press (Baolun Precision Detection Instrument Co., Ltd., BL-6170-B), set the pressure to 10 MPa, and the pressure holding time to 20 min. Then perform ploughing and cutting on a planer.

[0059] The depth of the micro-groove array after stamping is 300 μm, the width is 500 μm, and the distance between adjacent two grooves is 150 μm. The height of the protrusion at the bottom of the groove is 200 μm, the thickness is 150 μm, and the distance between adjacent two protrusions is 150 μm.

[0060] Fix the stamped sample on the planer fixture, as Figure 5 shown, perform ploughing and extrusion processing, and the cutting speed is 90 mm / s. Cut off the connection between the protrusion at the bottom of the groove and the groove side wall, and trim the protrusion into a duckbill-shaped inclined protrusion.

[0061] After ploughing, the height of the duckbill-shaped protrusion 6 becomes 100 μm, the inclination angle is 50°, and the included angle between the duckbill structure protrusion and the groove wall surface is 10°. The finally obtained microstructure with directional transportation is as Figure 3 shown.

[0062] This processing method is relatively simple compared with other methods, with low processing costs, controllable precision, and it is easier to process and produce a duckbill-shaped structure, thus achieving the effect of liquid directional transportation.

[0063] In order to enable those skilled in the art to better understand the solution of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the scope of protection of the present invention.

Claims

1. A cooling channel structure for liquid directional transportation, including microstructures with directional transportation, characterized in that: The microstructure with directional transportation includes a substrate, a microgroove structure, and a number of protrusions; the microgroove structure is arranged on the surface of the substrate along the droplet transportation direction; the number of protrusions is located in the microgroove structure, and adjacent protrusions are stacked on top of each other; The microgroove structure is a microgroove array structure, and the microgroove array structure is parallel to the droplet directional transportation direction; the depth of the microgroove array structure is 50-150 μm, the width of each groove is 100-950 μm, and the spacing between the grooves is 100-1000 μm; a number of protrusions are evenly distributed at the bottom of each groove, and the protrusions are inclined columns, forming a stacked structure; the cross-section of each protrusion is a duckbill shape, forming a duckbill-shaped protrusion; the radius of the arc of the cross-section of the duckbill-shaped protrusion is 10-500 μm, the angle between the duckbill-shaped protrusion and the groove wall surface is 0-30°, and the spacing between the duckbill-shaped protrusions is 30-150 μm; the inclination angle of each protrusion is 10-90°, the height is 50-400 μm, and the width is 80-900 μm; When processing the cooling channel structure for liquid directional transportation, first select the forming surface, polish the surface, use an imprinting forming punch to imprint the microgroove structure and the protrusions at the bottom of the groove on the substrate of the forming surface, and then use a ploughing extrusion tool to cut off the connection between the protrusions at the bottom of the groove and the side wall of the groove, and trim the protrusions into duckbill-shaped inclined protrusions.

2. The cooling channel structure for liquid directional transportation according to claim 1, characterized in that: The flatness of the polished surface should be less than 0.01 mm; the imprinting forming pressure is 1-50 Mpa; the ploughing extrusion process is one-way cutting, and the return tool does not contact the workpiece, and the cutting speed is 1-300 mm / s.

3. The cooling channel structure for liquid directional transportation according to claim 2, characterized in that: The substrate material includes copper.

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