Rapid cooling and shaping method for shoe upper

Abstract

The present invention relates to a shoe upper cooling and shaping method, comprising a shaping mechanism, the shaping mechanism comprising a front last, a front last clamping die, a front last clamping die cylinder, a transmission connection mechanism, a back last, a back last clamping die and a back last clamping die cylinder; the characteristic is that it also comprises a refrigeration system, a temperature sensor group and a PLC programmable controller, the front last, the front last clamping die, the back last and the back last clamping die are all made of heat-conducting materials, and the front last and the back last are provided with curved conformal refrigerant flow channels close to the surface, which can make the surface temperature of the front last and the back last uniform and the cooling speed fast, so that the shaping efficiency of the shoe upper is high, the shaping quality is good, and the energy saving is achieved. The shoe upper cooling and shaping method is achieved by the programmable controller according to the cooling and shaping process curve by changing the working frequency and time of the frequency converter, the cooling and shaping process curve includes the entire process of cooling, heat preservation and pressurization of the shoe last and the clamping die, and the temperature control in the cooling stage adopts a concave process curve to improve the cooling efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of shoe upper cooling and shaping, and in particular to a shoe upper rapid cooling and shaping method. Background Art

[0002] Shoe upper shaping is an important process in the shoemaking process. The shaping quality directly affects whether the shoes are comfortable and beautiful to wear. In the prior art, the shoe last is composed of a front last, a back last and a cooling block. Figure 1 As shown, the cooling block is embedded in the front (rear) last, as shown in Figure 2 and Figure 3 As shown, the flow channel in the refrigeration block is straight, and the distance between the flow channel and the front (rear) last surface is quite different, resulting in uneven surface temperature of the front (rear) last, affecting the shaping effect of the upper; on the other hand, the front (rear) last is cooled by the refrigeration block during operation, and this indirect cooling method is inefficient.

[0003] On the other hand, the cooling and shaping of the upper material in the prior art only stipulates two parameters, cooling and shaping working temperature and time, and does not optimize and control the cooling speed, temperature, time, etc. of the entire cooling and insulation process, so the efficiency and quality of cooling and shaping are not optimal; at the same time, the control method of the shoe last cooling is to control the temperature by determining the start or stop of the compressor based on the signal of the temperature sensor, and the compressor adopts a fixed-frequency compressor. When the upper material in a thermally activated state and with a high temperature is put on the shoe last, the compressor needs to work for a long time to reduce the temperature of the upper material to the process parameter requirements, and this temperature control method relying on the start and stop of the compressor has low accuracy, and the temperature fluctuation range is large during shaping (about ±2°C), which has an adverse effect on the efficiency and quality of shaping. Summary of the invention

[0004] In order to overcome the shortcomings of the prior art, the first purpose of the present invention is to provide a device for rapid cooling and shaping of a shoe upper. The second purpose of the present invention is to provide a method for rapid cooling and shaping of a shoe upper, which can make the surface temperature of the front last and the back last uniform, so that the shaping efficiency of the shoe upper is high, the shaping quality is good, and energy saving is achieved.

[0005] In order to achieve the above-mentioned first purpose, the present invention is implemented in this way, which is a shoe upper cooling and shaping device, including a shaping mechanism, the shaping mechanism includes a front last, a front last clamping die, a front last clamping die cylinder, a transmission connection mechanism, a back last, a back last clamping die and a back last clamping die cylinder, the transmission connection mechanism can be telescopic to adjust the distance between the front last and the back last, the front last clamping die cylinder can drive the front last clamping die to move forward and backward, and the back last clamping die cylinder can drive the back last clamping die to move forward and backward to apply pressure to the shoe upper material; it is characterized in that it also includes a refrigeration system, a temperature sensor group and a PLC programmable controller; the front last, the front last clamping die, the back last and the back last clamping die are all made of heat conductive materials;

[0006] A curved and conformable front-last refrigerant flow channel close to the front-last surface is provided in the front-last, a curved and conformable back-last refrigerant flow channel close to the back-last surface is provided in the back-last, a front-last clamping die refrigerant flow channel close to the front-last clamping die surface is provided in the front-last clamping die, and a back-last clamping die refrigerant flow channel close to the back-last clamping die surface is provided in the back-last clamping die;

[0007] The refrigeration system includes a compressor, a vapor-liquid separator, a condenser, a filter, a first electronic expansion valve, a frequency converter, a second electronic expansion valve, a third electronic expansion valve, a fourth electronic expansion valve, a fifth electronic expansion valve, a first check valve, a second check valve, a third check valve, and a fourth check valve; the compressor, the condenser, the filter, and the first electronic expansion valve are sequentially connected in series and communicated with a pipeline containing refrigerant, the refrigerant outlet of the vapor-liquid separator is communicated with the refrigerant inlet of the compressor; the refrigerant inlet of the vapor-liquid separator is respectively communicated with the refrigerant outlet of the refrigerant flow channel of the front mold through the first check valve, and the refrigerant outlet of the refrigerant flow channel of the front mold through the first check valve. The second one-way valve is communicated with the refrigerant outlet of the front last refrigerant flow channel, is communicated with the refrigerant outlet of the back last refrigerant flow channel through the third one-way valve, and is communicated with the refrigerant outlet of the back last clamping mold refrigerant flow channel through the fourth one-way valve; the refrigerant outlet of the first electronic expansion valve is communicated with the refrigerant inlet of the front last clamping mold refrigerant flow channel through the second electronic expansion valve, is communicated with the refrigerant inlet of the front last refrigerant flow channel through the third electronic expansion valve, is communicated with the refrigerant inlet of the back last refrigerant flow channel through the fourth electronic expansion valve, and is communicated with the refrigerant inlet of the back last clamping mold refrigerant flow channel through the fifth electronic expansion valve;

[0008] The temperature sensor group includes a front last clamping die temperature sensor, a front last temperature sensor, a back last temperature sensor and a front last clamping die temperature sensor; the front last clamping die temperature sensor is arranged on the front last clamping die for sensing the temperature of the front last clamping die; the front last temperature sensor is arranged on the front last for sensing the temperature of the front last; the back last temperature sensor is arranged on the back last for sensing the temperature of the back last; the back last clamping die temperature sensor is arranged on the back last clamping die for sensing the temperature of the back last clamping die;

[0009] The PLC programmable controller is respectively connected to the output end lines of the front last clamping mold temperature sensor, the front last temperature sensor, the back last temperature sensor and the back last clamping mold temperature sensor for controlling the frequency of the inverter to adjust the refrigeration power of the compressor.

[0010] In the technical solution, the frequency variation range of the frequency converter is 1-130 Hz, and the frequency converter determines the start and stop and the operating frequency according to the signal of the temperature sensor on the surface of the shoe last.

[0011] In the present technical solution, the cross-sections of the front last refrigerant flow channel, the back last refrigerant flow channel, the front last clamping mold refrigerant flow channel and the back last clamping mold refrigerant flow channel are all circular or elliptical.

[0012] In the present technical solution, the thermally conductive materials of the front last, the front last clamping mold, the back last and the back last clamping mold are all metals with good thermal conductivity such as aluminum alloy and copper alloy.

[0013] In the present technical solution, the refrigerant is R22, R410a, or R407c.

[0014] In order to achieve the above second object, the present invention is implemented as follows: it is a shoe upper cooling and shaping method, which is characterized by comprising:

[0015] Step 1: Set the cooling and shaping process parameter curve

[0016] According to the different materials of the upper, set the cooling and shaping working temperature, pressure and time process parameter curves of the front last, the front last clamping die, the back last and the back last clamping die;

[0017] Step 2: Place the upper material

[0018] Put the heat-activated upper material on the front and rear lasts, and start the transmission connection mechanism to extend it forward for tensioning;

[0019] Step 3: Cool and shape according to the process parameter curve

[0020] When the temperature sensor of the front last and the temperature sensor of the back last detect that the temperature of the surface of the shoe last rises by more than 2°C within 1 second, the PLC programmable controller controls the frequency converter to make the compressor immediately follow the set cooling and shaping process parameter curve, and changes the working frequency and time of the frequency converter to achieve the purpose of changing the cooling speed and temperature; at the same time, according to the setting of the process parameter curve, the front last clamping cylinder pushes the front last clamping cylinder, and the back last clamping cylinder pushes the back last clamping cylinder, and each presses the upper material at a given working pressure, and the given working pressure is 0.1-0.2MPa;

[0021] When the process parameter curve is in the rapid cooling stage, the PLC programmable controller controls the inverter to make the compressor work at a high operating frequency f1, which is 90Hz±15Hz. At the same time, all electronic expansion valves are opened to the maximum flow rate, thereby obtaining a high refrigeration capacity.

[0022] When the process parameter curve is in the slow cooling stage or the heat preservation stage, the PLC programmable controller controls the inverter operating frequency to drop to a lower operating frequency f2, and the lower operating frequency f2 is 25Hz±15Hz. At this time, the PLC programmable controller automatically adjusts the opening size of each electronic expansion valve according to the superheat of the refrigerant to adapt to the compressor operating frequency, thereby achieving energy saving effect;

[0023] Step 4: Remove the upper material

[0024] After cooling, pressurizing and heat preservation are completed according to the cooling and shaping process curve, the front last clamping mold cylinder, the rear last clamping mold cylinder and the transmission connection mechanism are retracted and released, and the upper material is removed to complete a working cycle.

[0025] In this technical solution, the cooling and shaping process curve includes the entire process of cooling, heat preservation and pressurization of the shoe last and the clamping mold. The temperature control in the cooling stage adopts Figure 7 The concave curve shown improves cooling efficiency.

[0026] Compared with the prior art, the advantages of the present invention are as follows: the present invention realizes digital control of the cooling speed and temperature throughout the entire process by setting a process parameter curve diagram of the entire cooling and heat preservation process and controlling the operating frequency of the compressor using a PLC programmable controller and a frequency converter, and has the advantages of process optimization, fast cooling speed, stable temperature (±0.5°C), and energy saving; the surface temperature of the front last and the back last is uniform, so that the upper material is cooled uniformly and defects caused by uneven cooling are reduced; the front last and the back last can be cooled quickly, which shortens the time for cooling and shaping the upper. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the back last structure of the prior art;

[0028] Figure 2 This is a schematic diagram of the structure of the refrigeration block of the back last in the prior art.

[0029] Figure 3 It is a schematic diagram of the internal structure of the refrigeration block of the back last in the prior art;

[0030] Figure 4 It is a structural schematic diagram of the back last of the present invention;

[0031] Figure 5 It is a structural schematic diagram of the front last of the present invention;

[0032] Figure 6 It is a connection diagram of the refrigeration system of the present invention;

[0033] Figure 7 It is a schematic diagram of the cooling and shaping process curve of the present invention.

[0034] Note Figure 7 The middle shoe last comprises a front last and a back last, and the clamping mold comprises a front last clamping mold and a back last clamping mold. DETAILED DESCRIPTION

[0035] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0036] like Figures 4 to 6 As shown, it is a shoe upper cooling and shaping device, including a refrigeration system, a shaping mechanism, a temperature sensor group and a PLC programmable controller 26, a front last 18, a front last clamping die 9, a front last clamping die cylinder 25, a transmission connection mechanism 19, a back last 20, a back last clamping die 23 and a back last clamping die cylinder 24, the transmission connection mechanism 19 can be telescopic to adjust the distance between the front last 18 and the back last 20, the front last clamping die cylinder 25 can drive the front last clamping die 9 to move forward and backward, and the front last clamping die cylinder 25 can drive the front last clamping die 9 to move forward and backward. The rear last clamping mold cylinder 24 can drive the rear last clamping mold 23 to move forward and backward to apply pressure to the upper material; the front last 18, the front last clamping mold 9, the rear last 20 and the rear last clamping mold 23 are all made of heat conductive materials; the front last clamping mold 9 can represent the left front last clamping mold and the right front last clamping mold, the front last 18 can represent the left front last and the right front last, the rear last 20 can represent the left rear last and the right rear last, and the rear last clamping mold 23 can represent the left rear last clamping mold and the right rear last clamping mold;

[0037] A curved and conformal front-last refrigerant flow channel 181 close to the surface of the front-last 18 is provided in the front-last 18, a curved and conformal back-last refrigerant flow channel 201 close to the surface of the back-last 20 is provided in the back-last 20, a front-last clamping mold refrigerant flow channel close to the surface of the front-last clamping mold 9 is provided in the front-last clamping mold 9, and a back-last clamping mold refrigerant flow channel close to the surface of the back-last clamping mold 23 is provided in the back-last clamping mold 23;

[0038] The refrigeration system comprises a compressor 1, a vapor-liquid separator 2, a condenser 3, a filter 4, a first electronic expansion valve 5, a frequency converter 6, a second electronic expansion valve 7, a third electronic expansion valve 11, a fourth electronic expansion valve 13, a fifth electronic expansion valve 15, a first check valve 8, a second check valve 12, a third check valve 14, and a fourth check valve 16; the compressor 1, the condenser 3, the filter 4 and the first electronic expansion valve 5 are sequentially connected in series and communicated with a pipeline containing refrigerant, the refrigerant outlet of the vapor-liquid separator 2 is communicated with the refrigerant inlet of the compressor 1; the refrigerant inlet of the vapor-liquid separator 2 is communicated with the refrigerant outlet of the refrigerant flow channel of the front mold through the first check valve 8, the refrigerant outlet of the refrigerant flow channel of the front mold, and the refrigerant outlet of the refrigerant flow channel of the front mold. The refrigerant outlet of the first electronic expansion valve 5 is communicated with the refrigerant inlet of the front last refrigerant flow channel 181 through the second one-way valve 12, the refrigerant outlet of the back last refrigerant flow channel 201 through the third one-way valve 14, and the refrigerant outlet of the back last clamping mold refrigerant flow channel through the fourth one-way valve 16; the refrigerant outlet of the first electronic expansion valve 5 is communicated with the refrigerant inlet of the front last clamping mold refrigerant flow channel through the second electronic expansion valve 7, the refrigerant inlet of the front last refrigerant flow channel 181 through the third electronic expansion valve 11, the refrigerant inlet of the back last refrigerant flow channel 201 through the fourth electronic expansion valve 13, and the refrigerant inlet of the back last clamping mold refrigerant flow channel through the fifth electronic expansion valve 15;

[0039] The temperature sensor group includes a front last clamping die temperature sensor 10, a front last temperature sensor 17, a back last temperature sensor 21 and a back last clamping die temperature sensor 22; the front last clamping die temperature sensor 10 is arranged on the front last clamping die 9 for sensing the temperature of the front last clamping die 9; the front last temperature sensor 17 is arranged on the front last 18 for sensing the temperature of the front last 18; the back last temperature sensor 21 is arranged on the back last 20 for sensing the temperature of the back last 20; the back last clamping die temperature sensor 22 is arranged on the back last clamping die 23 for sensing the temperature of the back last clamping die 23;

[0040] The PLC programmable controller 26 is respectively connected to the output end lines of the front last clamping mold temperature sensor 10, the front last temperature sensor 17, the back last temperature sensor 21 and the back last clamping mold temperature sensor 22 for controlling the frequency of the inverter 6 to adjust the refrigeration power of the compressor 1.

[0041] In this embodiment, the inverter 6 determines the start and stop and the operating frequency according to the signal of the shoe last surface temperature sensor. The frequency variation range of the inverter 6 is between 20-80Hz. The frequency variation range of the inverter 6 can also be selected according to actual conditions, but it must be within the range of 10-105Hz.

[0042] In this embodiment, the cross-sections of the front last refrigerant flow channel 181, the back last refrigerant flow channel 201, the front last clamping mold refrigerant flow channel and the back last clamping mold refrigerant flow channel are all circular or elliptical.

[0043] In this embodiment, the thermally conductive materials of the front shoe last 18, the front shoe last clamping die 9, the back shoe last 20 and the back shoe last clamping die 23 are all aluminum alloys, and copper alloys with good thermal conductivity may also be selected.

[0044] In this embodiment, the refrigerant is R22, and 410a or R407c may also be selected.

[0045] In this embodiment, the method for rapidly cooling and shaping a shoe upper comprises the following steps:

[0046] Step 1: Set the cooling and shaping process parameter curve

[0047] According to the different materials of the upper, the cooling and shaping working temperature, pressure and time process parameter curves of the front last 18, the front last clamping die 9, the back last 20 and the back last clamping die 23 are set, as shown in FIG. Figure 7 As shown;

[0048] Step 2: Place the upper material

[0049] The upper material after heat activation treatment is put on the front last 18 and the back last 20, and the transmission connection mechanism 19 is started to extend forward and tighten;

[0050] Step 3: Cool and shape according to the process parameter curve

[0051] When the temperature sensor 17 of the front last and the temperature sensor 21 of the back last detect that the temperature of the surface of the shoe last rises by more than 2°C within 1 second, the PLC programmable controller 26 controls the frequency converter 6 to make the compressor 1 immediately follow the set cooling and shaping process parameter curve, and achieves the purpose of changing the cooling speed and temperature by changing the working frequency and time of the frequency converter 6; at the same time, according to the setting of the process parameter curve, the front last clamping mold cylinder 25 pushes the front last clamping mold 9, and the back last clamping mold cylinder 24 pushes the back last clamping mold 23, and each presses the upper material at a working pressure of 0.15MPa; the working pressure can also be selected within the range of 0.1-0.2MPa according to the actual situation;

[0052] When the process parameter curve is in the rapid cooling stage, the PLC programmable controller 26 controls the inverter 6 to make the compressor 1 work at a high operating frequency f1, and the high operating frequency f1 is 80 Hz. At the same time, all electronic expansion valves are opened to the maximum flow rate, thereby obtaining a high refrigeration capacity;

[0053] When the process parameter curve is in the slow cooling stage or the heat preservation stage, the PLC programmable controller 26 controls the inverter 6 to operate at a lower operating frequency f2, and the lower operating frequency f2 is 20 Hz. At this time, the PLC programmable controller 26 automatically adjusts the opening size of each electronic expansion valve according to the superheat of the refrigerant to adapt to the compressor operating frequency, thereby achieving energy saving effect;

[0054] Step 4: Remove the upper material

[0055] After cooling, pressurizing and heat preservation are completed according to the cooling and shaping process curve, the front last clamping mold cylinder 25, the rear last clamping mold cylinder 24 and the transmission connection mechanism 19 are retracted to release the upper material. The upper material is removed to complete a working cycle.

[0056] In this embodiment, the cooling and shaping process curve includes the entire process of cooling, heat preservation and pressurization of the shoe last and the clamping mold. The temperature control in the cooling stage adopts a concave curve to improve the cooling efficiency, such as Figure 7 shown.

[0057] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions and deformations of these embodiments without departing from the principles and purposes of the present invention still fall within the scope of protection of the present invention.

Claims

1. A method for rapidly cooling and shaping a shoe upper, using a shaping mechanism, wherein the shaping mechanism comprises a front last (18), a front last clamping die (9), a front last clamping die cylinder (25), a transmission connection mechanism (19), a back last (20), a back last clamping die (23) and a back last clamping die cylinder (24), wherein the transmission connection mechanism (19) can be extended and retracted forward and backward to adjust the distance between the front last (18) and the back last (20), the front last clamping die cylinder (25) can drive the front last clamping die (9) to move forward and backward, and the back last clamping die cylinder (24) can drive the back last clamping die (23) to move forward and backward to apply pressure to the shoe upper material; characterized in that It also includes a refrigeration system, a temperature sensor group and a PLC programmable controller (26); the front last (18), the front last clamping mold (9), the back last (20) and the back last clamping mold (23) are all made of heat-conducting materials; A curved and conformable front-last refrigerant flow channel (181) close to the surface of the front-last (18) is provided in the front-last (18), a curved and conformable back-last refrigerant flow channel (201) close to the surface of the back-last (20) is provided in the back-last (20), a front-last clamping mold refrigerant flow channel close to the surface of the front-last clamping mold (9) is provided in the front-last clamping mold (9), and a back-last clamping mold refrigerant flow channel close to the surface of the back-last clamping mold (23) is provided in the back-last clamping mold (23); The refrigeration system comprises a compressor (1), a vapor-liquid separator (2), a condenser (3), a filter (4), a first electronic expansion valve (5), a frequency converter (6), a second electronic expansion valve (7), a third electronic expansion valve (11), a fourth electronic expansion valve (13), a fifth electronic expansion valve (15), a first check valve (8), a second check valve (12), a third check valve (14), and a fourth check valve (16); the compressor (1), the condenser (3), the filter (4), and the first electronic expansion valve (5) are sequentially connected in series and communicated with a pipeline containing refrigerant; the refrigerant outlet of the vapor-liquid separator (2) is communicated with the refrigerant inlet of the compressor (1); the refrigerant inlet of the vapor-liquid separator (2) is connected to the refrigerant flow channel of the front mold through the first check valve (8) and the refrigerant outlet of the vapor-liquid separator (2). The refrigerant outlet of the first electronic expansion valve (5) is connected to the refrigerant outlet of the front last refrigerant flow channel (181) through the second one-way valve (12), is connected to the refrigerant outlet of the back last refrigerant flow channel (201) through the third one-way valve (14), and is connected to the refrigerant outlet of the back last clamping mold refrigerant flow channel through the fourth one-way valve (16); the refrigerant outlet of the first electronic expansion valve (5) is connected to the refrigerant inlet of the front last clamping mold refrigerant flow channel through the second electronic expansion valve (7), is connected to the refrigerant inlet of the front last refrigerant flow channel (181) through the third electronic expansion valve (11), is connected to the refrigerant inlet of the back last refrigerant flow channel (201) through the fourth electronic expansion valve (13), and is connected to the refrigerant inlet of the back last clamping mold refrigerant flow channel through the fifth electronic expansion valve (15); The temperature sensor group comprises a front last clamping die temperature sensor (10), a front last temperature sensor (17), a back last temperature sensor (21) and a back last clamping die temperature sensor (22); the front last clamping die temperature sensor (10) is arranged on the front last clamping die (9) for sensing the temperature of the front last clamping die (9); the front last temperature sensor (17) is arranged on the front last (18) for sensing the temperature of the front last (18); the back last temperature sensor (21) is arranged on the back last (20) for sensing the temperature of the back last (20); the back last clamping die temperature sensor (22) is arranged on the back last clamping die (23) for sensing the temperature of the back last clamping die (23); The PLC programmable controller (26) is respectively connected to the output end circuits of the front last clamping mold temperature sensor (10), the front last temperature sensor (17), the back last temperature sensor (21) and the back last clamping mold temperature sensor (22) for controlling the frequency of the inverter (6) to adjust the cooling power of the compressor (1). ； The characteristic is that its shaping method includes: Step 1: Set the cooling and shaping process parameter curve According to different materials of the upper, a process parameter curve diagram of cooling and shaping working temperature, pressure and time of the front last (18), the front last clamping die (9), the back last (20) and the back last clamping die (23) is set; Step 2: Place the upper material The upper material after heat activation treatment is put on the front last (18) and the back last (20), and the transmission connection mechanism (19) is started to extend forward for tensioning; Step 3: Cool and shape according to the process parameter curve When the temperature sensor for the front last (17) and the temperature sensor for the back last (21) detect that the temperature of the surface of the shoe last rises by more than 2°C within 1 second, the PLC programmable controller (26) controls the frequency converter (6) to make the compressor (1) immediately change the cooling speed and temperature according to the set cooling and shaping process parameter curve, by changing the working frequency and time of the frequency converter (6); at the same time, according to the setting of the process parameter curve, the front last clamping mold cylinder (25) pushes the front last clamping mold (9), and the back last clamping mold cylinder (24) pushes the back last clamping mold (23), and each presses the upper material at a given working pressure, and the given working pressure is 0.1-0.2MPa; When the process parameter curve is in the rapid cooling stage, the PLC programmable controller (26) controls the frequency converter (6) to make the compressor (1) operate at a high operating frequency f1, and the high operating frequency f1 is 90 Hz ± 15 Hz, and at the same time all electronic expansion valves are opened to the maximum flow rate, thereby obtaining a high refrigeration capacity; When the process parameter curve is in the slow cooling stage or the heat preservation stage, the PLC programmable controller (26) controls the frequency converter (6) to reduce the operating frequency to a lower operating frequency f2, and the lower operating frequency f2 is 25 Hz ± 15 Hz. At this time, the PLC programmable controller (26) automatically adjusts the opening size of each electronic expansion valve according to the superheat of the refrigerant to adapt to the operating frequency of the compressor, thereby achieving energy saving effect; Step 4: Remove the upper material After cooling, pressurizing and heat preservation are completed according to the cooling and shaping process curve, the front last clamping mold cylinder (25), the rear last clamping mold cylinder (24) and the transmission connection mechanism (19) are retracted to release the upper material; the upper material is removed, and a working cycle is completed; The cooling and shaping process curve includes the entire process of cooling, heat preservation and pressurization of the shoe last and the clamping mold. The temperature control in the cooling stage adopts a concave curve to improve the cooling efficiency.

2. The method for rapid cooling and shaping of a shoe upper according to claim 1, characterized in that The frequency variation range of the frequency converter (6) is 10-105 Hz. The frequency converter (6) determines the start and stop and the operating frequency according to the signal of the temperature sensor on the surface of the shoe last.

3. The method for rapid cooling and shaping of a shoe upper according to claim 1, characterized in that The cross-sections of the front last refrigerant flow channel (181), the back last refrigerant flow channel (201), the front last clamping mold refrigerant flow channel, and the back last clamping mold refrigerant flow channel are all circular or elliptical.

4. The method for rapid cooling and shaping of a shoe upper according to claim 1, characterized in that The heat-conducting materials of the front shoe last (18), the front shoe last clamping mold (9), the back shoe last (20) and the back shoe last clamping mold (23) are all metals with good heat conductivity, such as aluminum alloy and copper alloy.

5. The method for rapid cooling and shaping of a shoe upper according to claim 1, characterized in that The refrigerant is R22, R410a, or R407c.

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