Checking fixture for heat dissipation device

Abstract

The utility model provides a testing fixture for a heat dissipation device, the heat dissipation device comprises a heat dissipation device and a fan arranged on one side of the heat dissipation device, the fan is provided with a wind scooper and a plurality of blades arranged in the wind scooper, the testing fixture comprises a fixing part, an axial mandrel and a measuring part, the fixing part is used for being fixed on the edge of one side, deviating from the heat dissipation device, of the wind scooper, the axial mandrel slidably penetrates through the fixing part in the axial direction of the fan and is provided with a first identification area, the measuring part is slidably arranged on the axial mandrel, and when the axial mandrel abuts against the surface of the radiator in the axial direction of the fan and the measuring part abuts against the edge of the side, away from the radiator, of the blade, the first identification area corresponds to the first identification area. Whether the distance between the blade and the radiator is in a qualified range is determined by observing whether the measuring part is in the first identification area. The detection tool can detect the distance between the blade and the radiator, and can improve the detection accuracy and the operation convenience.

Description

Technical Field

[0001] The present application relates to a detection device, and in particular to a detection fixture for a heat dissipation device. Background Art

[0002] The cooling system of construction machinery is generally composed of a radiator and a fan. The fan includes an air guide cover and blades. The blades are driven by a driving source such as a diesel engine, an electric motor or a motor to dissipate heat for the radiator. Figure 1 As shown, when assembling the heat dissipation system, the distance A between the blades and the heat sink needs to be kept within a qualified size range.

[0003] In the prior art, after assembly, in order to detect the distance A, installers often use a tape measure to extend into the fan for measurement. This detection method has low accuracy and needs further improvement. Utility Model Content

[0004] The present application provides a detection fixture for a heat dissipation device, which can detect the distance between a blade and a heat sink and can improve detection accuracy and operational convenience.

[0005] In order to achieve the above objectives, this application adopts the following technical solutions:

[0006] The present application provides a testing fixture for a heat dissipation device, the heat dissipation device comprising a radiator and a fan arranged on one side of the radiator, the fan having an air guide cover and a plurality of blades arranged inside the air guide cover; the testing fixture comprising: a fixing portion, the fixing portion being fixed to an edge of the air guide cover on a side facing away from the radiator; an axial core shaft, the axial core shaft being slidably inserted into the fixing portion along the axial direction of the fan, the axial core shaft being provided with a first marking area; a measuring portion, the measuring portion being slidably arranged on the axial core shaft; when the axial core shaft contacts the surface of the radiator along the axial direction of the fan and the measuring portion contacts the edge of the blade on the side facing away from the radiator, the measuring portion is in the first marking area, and the distance between the blade and the radiator is within an acceptable range.

[0007] In a possible embodiment, a second identification area is provided on the axial core shaft; when the axial core shaft contacts the surface of the radiator, the edge of the fixing portion away from the air guide cover is in the second identification area, and the width of the air guide cover is within an acceptable range.

[0008] In a possible embodiment, the gauge further includes: a first pre-tightening portion, which is sleeved on the axial core shaft and connected to the measuring portion to provide a force for pressing the measuring portion against the blade.

[0009] In a possible implementation, the inspection fixture further includes: a second pre-tightening portion, which is sleeved on the axial core shaft and connected to the fixing portion to provide a force for the axial core shaft to contact the heat sink.

[0010] In a possible implementation, the fixing portion has a snap-in groove for snapping into the edge of the air guide cover.

[0011] In a possible embodiment, the fixing portion has a first sliding through groove for the axial core shaft to pass through.

[0012] In a possible embodiment, the inspection fixture further includes: a radial core shaft, which is slidably inserted into the fixed portion along the radial direction of the fan, and the radial core shaft is provided with a third identification area; when the radial core shaft contacts the blade, the edge of the fixed portion away from the blade is in the third identification area, and the distance between the blade and the wind guide cover is within a qualified range.

[0013] In a possible implementation, the gauge further includes: a third pre-tightening portion, which is sleeved on the radial core shaft and connected to the fixing portion to provide a force for the radial core shaft to move away from the blade.

[0014] In a possible embodiment, the fixing portion has a second sliding through groove for the radial core shaft to pass through.

[0015] In a possible embodiment, an anti-slip protrusion is provided on a side of the radial core shaft close to the blade; and an accommodating groove for accommodating the anti-slip protrusion is provided in the fixing portion.

[0016] The inspection fixture of the present application has a fixing portion fixed to the edge of the side of the air guide cover facing away from the radiator, an axial core shaft is slidably inserted into the fixing portion along the axial direction of the fan, and a measuring portion is slidably arranged on the axial core shaft. The axial core shaft contacts the surface of the radiator along the axial direction of the fan, and when the measuring portion contacts the edge of the blade facing away from the radiator, whether the distance between the blade and the radiator is within the qualified range is determined by observing whether the measuring portion is in the first identification area. In this way, the direction of the axial core shaft is strictly controlled by the fixing portion during inspection, which makes the detected distance between the blade and the radiator more accurate, and the inspection means is convenient and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0018] Figure 1 It is a structural diagram of a heat dissipation system in the prior art;

[0019] Figure 2 This is a schematic diagram of the coordination relationship between the heat dissipation system and the inspection fixture in one embodiment of the present application;

[0020] Figure 3 yes Figure 2 The local cross-section view obtained along the DD cutting line;

[0021] Figure 4 yes Figure 2 The local cross-section view obtained along the EE section line;

[0022] Description of reference numerals:

[0023] 10. Radiator; 20. Fan; 22. Air guide cover; 24. Blade; 100. Fixing part; 120. Clamping groove; 130. Upper clamping plate; 140. Lower clamping plate; 150. First sliding groove; 160. Second sliding groove; 170. Accommodating groove; 200. Axial core shaft; 210. First identification area; 220. Second identification area; 230. First abutment platform; 240. Second abutment platform; 300. Measuring part; 400. First pre-tightening part; 500. Second pre-tightening part; 600. Radial core shaft; 610. Third identification area; 620. Anti-slip protrusion; 630. Third abutment platform; 700. Third pre-tightening part. DETAILED DESCRIPTION

[0024] To make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0025] like Figure 1 As shown, the cooling system for construction machinery generally includes a radiator 10 and a fan 20. Fan 20 includes an air scoop 22 and blades 24. Blades 24 are driven by a source such as a diesel engine, electric motor, or motor. The rotation of blades 24 creates a heat exchange airflow with radiator 10. During assembly of the cooling system, the distance A between blades 24 and radiator 10 must be maintained within an acceptable dimensional range.

[0026] In the prior art, after assembly, in order to detect the distance A between the blades 24 and the heat sink 10 , installers often use a tape measure to reach into the fan 20 for measurement. This detection method has low accuracy and needs further improvement.

[0027] Based on this, the present application proposes a testing fixture for a heat dissipation system, wherein the fixing part of the testing fixture is fixed to the edge of the side of the air guide cover facing away from the radiator, the axial core shaft is slidably inserted into the fixing part along the axial direction of the fan, and the measuring part is slidably arranged on the axial core shaft. The axial core shaft contacts the surface of the radiator along the axial direction of the fan, and when the measuring part contacts the edge of the blade facing away from the radiator, whether the distance between the blade and the radiator is within the qualified range is determined by observing whether the measuring part is in the first identification area. In this way, the direction of the axial core shaft is strictly controlled by the fixing part during detection, which makes the detected distance between the blade and the radiator more accurate, and the detection means is convenient and easy to operate.

[0028] The following will be combined Figures 1 to 4 The contents of this application are described in detail so that those skilled in the art can understand the contents of this application more clearly and in detail.

[0029] The present application provides a testing fixture for a heat dissipation device. The heat dissipation device may include a heat sink 10 and a fan 20 disposed on one side of the heat sink 10. The fan 20 includes an air scoop 22 and a plurality of blades 24 disposed within the air scoop 22. The plurality of blades 24 are driven by a motor to form a heat exchange airflow with the heat sink 10.

[0030] The inspection tool can be used at least to detect the distance A between the blade 24 and the radiator 10. Specifically, the inspection tool may include a fixing portion 100, an axial core shaft 200 and a measuring portion 300. The fixing portion 100 is used to be fixed to the edge of the side of the air guide cover 22 facing away from the radiator 10. The axial core shaft 200 is slidably arranged in the fixing portion 100 along the axial direction of the fan 20, and the axial core shaft 200 is provided with a first identification area 210. The measuring portion 300 is slidably arranged on the axial core shaft 200. When the axial core shaft 200 is in contact with the surface of the radiator 10, and the measuring portion 300 is in contact with the edge of the blade 24 facing away from the radiator 10, when the measuring portion 300 is in the first identification area 210, the distance A between the blade 24 and the radiator 10 is in the qualified range.

[0031] In this embodiment, the shape of the fixing portion 100 can be configured to match the contour of the air scoop 22, so that the fixing portion 100 can be fixedly mounted on the edge of the air scoop 22 facing away from the heat sink 10. Since the air scoop 22 is generally circular in design, the fixing portion 100 can be moved along the edge of the air scoop 22 before being fixed, so as to be positioned according to the position of the blades 24. During testing, after the fixing portion 100 is moved to the appropriate position, it can be fixed to the air scoop 22 using fasteners.

[0032] In this embodiment, since the axial core shaft 200 is slidably provided in the fixing portion 100 along the axial direction of the fan 20, the measuring portion 300 can be slidably provided on the axial core shaft 200. When the axial core shaft 200 abuts against the surface of the radiator 10 and the measuring portion 300 abuts against the edge of the blade 24 facing away from the radiator 10, the measuring portion 300 determines the sum M of the axial thickness F of the blade 24 and the distance A between the blade 24 and the radiator 10 on the axial core shaft 200. Since the thickness F of the blade 24 is fixed, M can be used to measure whether the distance A between the blade 24 and the radiator 10 is within the qualified range.

[0033] In this embodiment, the axial core shaft 200 is provided with a first identification area 210, and the first identification area 210 can be highlighted by means of color, pattern, etc. The first identification area 210 can be marked according to the upper and lower thresholds of the qualified range and the thickness F of the blade 24. For example, if the upper threshold of the qualified range is S1 and the lower threshold is S2, then the distance S1+F can be measured from the end of the axial core shaft 200 that abuts the heat sink 10 and marked as the upper threshold endpoint of the first identification area 210, and the distance S2+F can be measured from the end of the axial core shaft 200 that abuts the heat sink 10 and marked as the lower threshold endpoint of the first identification area 210.

[0034] In this way, when the axial core shaft 200 contacts the surface of the radiator 10 and the measuring part 300 contacts the edge of the blade 24 facing away from the radiator 10, it is possible to determine whether the distance between the blade 24 and the radiator 10 is within the qualified range by observing whether the measuring part 300 is in the first identification area 210.

[0035] In some embodiments, a second identification area 220 is provided on the axial core shaft 200. When the axial core shaft 200 contacts the surface of the heat sink 10, the edge of the fixing portion 100 is in the second identification area 220, and the width C of the air guide cover 22 is within the qualified range.

[0036] In this embodiment, during testing, the fixing portion 100 is fixed to the air guide cover 22, so that the relative position relationship between the fixing portion 100 and the air guide cover 22 is determined. Since the air guide cover 22 is usually arranged close to the surface of the radiator 10, when the axial core shaft 200 contacts the surface of the radiator 10, the distance determined on the axial core shaft 200 from the edge of the fixing portion 100 away from the air guide cover 22 can be used to measure the thickness of the air guide cover 22.

[0037] In this embodiment, the axial core shaft 200 is provided with a second identification area 220, which can be highlighted by color, pattern, etc. The second identification area 220 can be marked according to the upper and lower thresholds of the qualified range and the relative position relationship parameters of the fixing portion 100 and the air guide cover 22.

[0038] In some specific embodiments, when the fixing portion 100 is installed on the air guide cover 22, the fixing portion 100 protrudes from the air guide cover 22 in the axial direction, and the length of the protruding portion (set as G) is constant and determinable. The upper threshold value of the qualified range of the width of the air guide cover 22 is P1, and the lower threshold value is P2. Then, the distance P1+G can be measured from the end of the axial core shaft 200 that is against the heat sink 10 and marked as the upper threshold endpoint of the second identification area 220, and the distance P2+G can be measured from the end of the axial core shaft 200 that is used to be against the heat sink 10 and marked as the lower threshold endpoint of the second identification area 220.

[0039] Thus, when the axial core shaft 200 contacts the surface of the heat sink 10 , it is possible to determine whether the width of the air guide cover 22 is within the qualified range by observing whether the edge of the fixing portion 100 away from the air guide cover 22 is in the second identification area 220 .

[0040] In some embodiments, the inspection tool may further include a first pre-tightening portion 400, which is sleeved on the axial core shaft 200 and connected to the measuring portion 300 to provide the measuring portion 300 with a force to press it against the blade 24. In this way, when inspecting whether the distance between the blade 24 and the radiator 10 is within the qualified range, the inspector does not need to press the measuring portion 300 with his hands all the time, which facilitates the inspection operator's operation.

[0041] In some specific embodiments, the total length of the axial mandrel 200 is configured such that when its first end contacts the surface of the heat sink 10, its second end protrudes beyond the blade 24. A first abutment 230 is provided near the second end of the axial mandrel 200, and the measuring portion 300 is located on the side of the first abutment 230 facing away from the second end of the axial mandrel 200. The first preload portion 400, which may be a compression spring, is mounted on the axial mandrel 200, with one end abutting the first abutment 230 and the other end abutting the measuring portion 300.

[0042] When the first end of the axial core shaft 200 contacts the surface of the radiator 10 and the measuring part 300 contacts the edge of the blade 24 facing away from the radiator 10, the first pre-tightening part 400 is compressed, and the first pre-tightening part 400 provides a pre-tightening force for the measuring part 300 to move toward the blade 24, so that it is pressed against the blade 24.

[0043] In some embodiments, the inspection tool may further include a second pre-tightening portion 500, which is sleeved on the axial core shaft 200 and connected to the fixing portion 100 to provide a force for the axial core shaft 200 to contact the heat sink 10. This eliminates the need for the inspector to manually press the axial core shaft 200 when inspecting whether the distance between the blades 24 and the heat sink 10 is within the acceptable range, facilitating the inspection.

[0044] In some specific embodiments, a second abutment 240 is provided on the axial core shaft 200, and the second abutment 240 is located between the first end of the axial core shaft 200 and the fixed portion 100. The second pre-tightening portion 500 can be a compression spring, which is sleeved on the axial core shaft 200, with one end abutting the second abutment 240 and the other end abutting the fixed portion 100. In a natural state, under the action of the second pre-tightening portion 500, the length of the axial core shaft 200 from the position of the fixed portion 100 to its first end is greater than the distance between the fixed portion 100 and the heat sink 10. When the first end of the axial core shaft 200 abuts against the surface of the heat sink 10, the axial core shaft 200 is pushed out toward the second end, and the second pre-tightening portion 500 is compressed. The second pre-tightening portion 500 provides a pre-tightening force for the axial core shaft 200 to move toward the heat sink 10, so that the axial core shaft 200 can be pressed against the heat sink 10.

[0045] In some embodiments, the fixing portion 100 has a snap-fitting slot 120 for snapping onto the edge of the air scoop 22. When installing the fixing portion 100, the snap-fitting slot 120 is used to pre-fix the fixing portion 100 to the edge of the air scoop 22. The position of the fixing portion 100 is then adjusted along the edge of the air scoop 22 according to the position of the blades 24. Finally, the fixing portion 100 is secured to the edge of the air scoop 22 using fasteners.

[0046] In some embodiments, the fixing portion 100 has a first sliding groove 150 for the axial core shaft 200 to pass through.

[0047] When installing the axial core shaft 200, the axial core shaft 200 can be first inserted into the first sliding groove 150, and then the second pre-tightening part 500 and the second abutment platform 240 can be installed in sequence from the first end of the axial core shaft 200, and the first pre-tightening part 400 and the first abutment platform 230 can be installed in sequence from the second end of the axial core shaft 200.

[0048] In some embodiments, the inspection fixture may further include a radial core shaft 600, which is slidably disposed in the radial direction of the fan 20 and passes through the fixing portion 100. The radial core shaft 600 is provided with a third identification area 610. When the radial core shaft 600 contacts the blade 24, the edge of the fixing portion 100 facing away from the blade 24 is in the third identification area 610, and the distance between the blade 24 and the wind guide 22 is within the acceptable range.

[0049] In this embodiment, after the fixing portion 100 is fixed to the air scoop 22, the distance between the fixing portion 100 and the air scoop 22 is fixed. When the radial core 600 contacts the blades 24 along the radial direction of the fan 20, the distance between the edge of the fixing portion 100 and the axial core 200 can be used to measure the thickness of the air scoop 22.

[0050] The axial core shaft 200 is provided with a third identification area 610 , which can be highlighted by color, pattern, etc. The third identification area 610 can be marked according to the upper and lower thresholds of the qualified range and the size parameters of the fixing portion 100 and the air guide cover 22 .

[0051] For example, in some specific embodiments, when the fixing portion 100 has an upper clamping plate 130 and a lower clamping plate 140, a snap-fit ​​groove 120 is formed between the upper clamping plate 130 and the lower clamping plate 140. During installation and fixing, the snap-fit ​​groove 120 is snapped onto the edge of the air scoop 22. Assuming that the upper threshold value of the qualified range of the distance between the blade 24 and the air scoop 22 is Q1, the lower threshold value is Q2, the thickness of the upper clamping plate 130 is H, and the thickness of the air scoop 22 is I, then the distance Q1+H+I can be measured from the end of the radial core shaft 600 that is used to abut against the blade 24 and marked as the upper end point of the third identification area 610, and the distance Q2+H+I can be measured from the end of the axial core shaft 200 that is used to abut against the radiator 10 and marked as the lower end point of the second identification area 220.

[0052] In this way, when the axial core shaft 200 contacts the surface of the heat sink 10 , it can be determined whether the width of the air guide cover 22 is within the qualified range by observing whether the edge of the fixing portion 100 is in the second identification area 220 .

[0053] In some embodiments, the gauge may further include a third pre-tightening portion 700 . The third pre-tightening portion 700 is sleeved on the radial core shaft 600 and connected to the fixing portion 100 to provide a force for the radial core shaft 600 to move away from the blade 24 .

[0054] In some specific embodiments, the radial mandrel 600 is provided with a third abutment 630, located outside the fixing portion 100. The third preload portion 700 may be a compression spring, which is mounted on the radial mandrel 600, with one end abutting the third abutment 630 and the other end abutting the fixing portion 100. In its natural state, the third preload portion 700 supports the radial mandrel 600 radially outward from the fan 20. During testing, the inspector presses the radial mandrel 600 radially inwardly of the fan 20, causing the end of the radial mandrel 600 to abut against the blades 24. This compresses the third preload portion 700, generating a restoring force radially outward from the fan 20. After testing is complete, the radial mandrel 600 is released from the axial mandrel 200, and this restoring force causes the radial mandrel 600 to eject. This design prevents contact between the radial mandrel 600 and the blades 24 when testing is not in progress or when the fixing portion 100 is not being moved.

[0055] In some embodiments, the fixing portion 100 has a second sliding groove 160 for the radial core shaft 600 to pass through.

[0056] When installing the radial core shaft 600 , the radial core shaft 600 may be first inserted into the second sliding groove 160 , and then the third pre-tightening portion 700 and the third abutting platform 630 may be installed in sequence from the radial outer end of the radial core shaft 600 .

[0057] In some embodiments, a side of the radial core shaft 600 close to the blade 24 is provided with an anti-slip protrusion 620. A receiving groove 170 for receiving the anti-slip protrusion 620 is provided in the fixing portion 100.

[0058] The anti-slip protrusion 620 protrudes from the radial core shaft 600 . When the third pre-tightening portion 700 is in a natural state, the anti-slip protrusion 620 abuts against the radial inner side of the fixing portion 100 to prevent the radial core shaft 600 from slipping out.

[0059] The accommodating groove 170 can be set on the fixed radial inner side, so that the third pre-tightening part 700 can hide the anti-slip protrusion 620 in the fixed part 100 in a natural state, thereby avoiding the anti-slip protrusion 620 from contacting the blade 24 when the fixed part 100 is not detected or moved.

[0060] It should be noted that references in this specification to "one embodiment," "an embodiment," "an exemplary embodiment," "some embodiments," and the like indicate that the described embodiment may include a particular feature, structure, or characteristic, but not necessarily every embodiment includes that particular feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in conjunction with an embodiment, it is within the knowledge of those skilled in the art to implement such feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A test fixture for a heat dissipation device, the heat dissipation device comprising a heat sink (10) and a fan (20) arranged on one side of the heat sink (10), the fan (20) having an air guide cover (22) and a plurality of blades (24) arranged inside the air guide cover (22); characterized in that: The inspection tool comprises: a fixing portion (100), the fixing portion (100) being used to be fixed to an edge of a side of the air guide cover (22) facing away from the radiator (10); an axial core shaft (200), the axial core shaft (200) being slidably disposed in the fixing portion (100) along the axial direction of the fan (20), and the axial core shaft (200) being provided with a first identification area (210); a measuring portion (300), the measuring portion (300) being slidably disposed on the axial core shaft (200); When the axial core shaft (200) contacts the surface of the radiator (10) along the axial direction of the fan (20), and the measuring portion (300) contacts the edge of the blade (24) facing away from the radiator (10), when the measuring portion (300) is in the first identification area (210), the distance between the blade (24) and the radiator (10) is within a qualified range.

2. The inspection tool according to claim 1, characterized in that: A second marking area (220) is provided on the axial core shaft (200); When the axial core shaft (200) contacts the surface of the heat sink (10), and the edge of the fixing portion (100) facing away from the air guide cover (22) is in the second identification area (220), the width of the air guide cover (22) is within a qualified range.

3. The inspection tool according to claim 1, characterized in that: Also includes: A first pre-tightening portion (400) is sleeved on the axial core shaft (200) and connected to the measuring portion (300) to provide the measuring portion (300) with a force to press the measuring portion (300) against the blade (24).

4. The inspection tool according to claim 1, wherein: Also includes: A second pre-tightening portion (500) is sleeved on the axial core shaft (200) and connected to the fixing portion (100) to provide the axial core shaft (200) with a force causing it to contact the heat sink (10).

5. The inspection tool according to claim 1, wherein: The fixing portion (100) has a snap-fitting groove (120) for snapping onto the edge of the air guide cover (22).

6. The gauge according to claim 1, wherein: The fixing portion (100) has a first sliding groove (150) for the axial core shaft (200) to pass through.

7. The gauge according to any one of claims 1 to 6, characterized in that: Also includes: a radial core shaft (600), the radial core shaft (600) being slidably disposed in the fixing portion (100) along the radial direction of the fan (20), and the radial core shaft (600) being provided with a third identification area (610); When the radial core shaft (600) contacts the blade (24), the edge of the fixing portion (100) facing away from the blade (24) is in the third identification area (610), and the distance between the blade (24) and the air guide cover (22) is within a qualified range.

8. The gauge according to claim 7, characterized in that: Also includes: A third pre-tightening portion (700) is sleeved on the radial core shaft (600) and connected to the fixing portion (100) to provide a force for the radial core shaft (600) to move it away from the blade (24).

9. The gauge according to claim 7, wherein: The fixing portion (100) has a second sliding groove (160) for the radial core shaft (600) to pass through.

10. The gauge according to claim 7, wherein: An anti-dropout protrusion (620) is provided on one side of the radial core shaft (600) close to the blade (24); The fixing portion (100) is provided with an accommodating groove (170) for accommodating the anti-slip protrusion (620).

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