Rapid self-centering clamp for rough machining of double-hole casting blank

Abstract

The rapid self-centering clamp comprises a bottom plate, a fixed side centering unit, a movable side centering unit and a plurality of side top units, the fixed side centering unit and the movable side centering unit are installed on the bottom plate front and back, and the side top units are installed on the bottom plate left and right. The fixed side centering unit comprises a first tip, a first tip seat and a first screw rod, the first screw rod transversely penetrates through the first tip seat and is in threaded connection with the first tip seat, the first tip is fixed to the front end of the first screw rod, the first tip seat is fixed to the bottom plate, and the movable side centering unit comprises a second tip, a second tip seat and a second screw rod; the second screw transversely penetrates through the second center seat and is in threaded connection with the second center seat, the second center is fixed to the front end of the second screw, and the second center seat is installed on the bottom plate in a front-back sliding mode. The clamp is low in machining cost and convenient and flexible to use, rapid clamping and rapid self-centering of rough machining of the double-hole casting blank can be achieved, the clamping alignment time is shortened, and the production efficiency is improved.

Description

Technical Field

[0001] The invention relates to a clamp, in particular to a rapid self-centering clamp for rough machining of double-hole casting blanks. Background Art

[0002] Rough machining of blanks with holes is the first step in machining. Usually, according to the size of the blank to be machined, simple tools commonly used in the workshop are used for clamping, but there are few special fixtures for rough machining. Before machining, it is generally necessary to allocate allowances according to the holes and perform alignment. Due to the poor surface accuracy and difficulty in controlling allowances of the blanks, it usually takes a long time to clamp and calculate the allocation of allowances during rough machining, or to pre-allocate allowances by marking, which takes a long time to align. If the blank of the casting is a double-hole structure, it will take more time to align, and the clamping efficiency is low, which greatly affects the production efficiency of parts, especially for parts with large quantities and large processing volumes.

[0003] CN222471636U discloses a hydraulic clamp for rough machining of a left steering knuckle, comprising a clamp body, on which a first end positioning pin, a second end positioning pin and a third end positioning pin arranged in a triangle are arranged, a vertically lifting chamfering positioning pin is arranged on the connecting line between the first end positioning pin and the third end positioning pin, a side positioning seat is arranged on the clamp body, a horizontally arranged positioning screw is arranged on the side positioning seat, and a pressure plate is arranged above the first end positioning pin, the second end positioning pin and the third end positioning pin, and a horizontally movable side pressure head is arranged in the opposite direction of the positioning screw. The side pressure head, locking mechanism, chamfering positioning pin and other key structures adopted by the clamp are all driven by oil cylinders, which is costly, the clamp structure is complex, and the manufacturing cost is high. It can only be applied to the rough machining clamping of the left steering knuckle, and has poor versatility. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a rapid self-centering fixture for rough machining of double-hole casting blanks in view of the deficiencies in the prior art. The fixture has low machining cost and is easy and flexible to use. It can realize rapid clamping and rapid self-centering of rough machining of double-hole casting blanks, shorten the clamping and alignment time of double-hole casting blanks, and improve the production efficiency of double-hole casting blanks.

[0005] The technical solution adopted by the present invention to solve the above technical problems is: a rapid self-centering fixture for rough machining of double-hole casting blanks, comprising a base plate, a fixed side centering unit, a movable side centering unit and a plurality of side top units, wherein the fixed side centering unit and the movable side centering unit are installed on the base plate at intervals in front and back, and the plurality of side top units are installed on the base plate at intervals in left and right, the fixed side centering unit comprises a first top, a first top seat and a first screw, the first screw crosses the first top seat and is threadedly connected to the first top seat, the first top is coaxially fixed to the front end of the first screw, the first top seat is fixed to the base plate, the movable side centering unit comprises a second top, a second top seat and a second screw, the second screw crosses the second top seat and is threadedly connected to the second top seat, the second top is coaxially fixed to the front end of the second screw, the second top seat can be slidably installed on the base plate in front and back, the first top and the second top are used for front and rear centering and pressing the front and rear butt holes of the double-hole casting blank to be clamped, and the plurality of side top units are used for clamping the double-hole casting blank in left and right directions.

[0006] The clamp of the present invention takes the front and rear facing holes of the double-hole casting blank as a reference, uses the first and second tops to center and tighten the front and rear facing holes of the double-hole casting blank, and clamps the double-hole casting blank left and right through multiple side top units, so as to realize the rapid clamping and rapid self-centering of the rough processing of the double-hole casting blank, shorten the clamping and alignment time of the double-hole casting blank, and improve the production efficiency of the double-hole casting blank. The distance between the first and second tops can be conveniently adjusted by rotating the first screw and the second screw, which is easy to operate and meets the clamping needs of double-hole casting blanks of different lengths.

[0007] The clamp of the present invention has low precision requirements for each component, low processing cost, convenient and flexible use, and meets the clamping needs of rough processing of double-hole casting blanks of different specifications within a certain size range.

[0008] Preferably, the first top seat is a trapezoid with a small top and a large bottom. The first top seat is provided with a first threaded hole connected front to back, two first countersunk holes connected up and down, and two positioning pin holes. The first threaded hole is used to install the first screw rod, and the two first countersunk holes are used to install two first screws. The two first screws are threadedly connected to the base plate. The two positioning pin holes are provided at the bottom of the first top seat. The two positioning pin holes are used to install two positioning pins. The two positioning pins are positioned and connected to the base plate. The first top seat is installed on the base plate by means of the two first screws and the two positioning pins. The operation is convenient and the installation is reliable. The design of the first countersunk hole facilitates the installation of the first screw.

[0009] Preferably, two T-shaped slots are provided on the upper part of the bottom plate, and the two T-shaped slots are arranged in parallel on the left and right sides. Two T-shaped blocks are fixed on the bottom of the second top seat, and each T-shaped block is slidably connected to one of the T-shaped slots. The T-shaped blocks cooperate with the T-shaped slots to realize the installation of the second top seat on the bottom plate, and guide the forward and backward sliding of the second top seat, while limiting the freedom of the second top seat in the left and right directions, and the structure is simple and reliable.

[0010] Furthermore, the second top seat is a trapezoid with a small top and a large bottom, and the second top seat is provided with a second threaded hole connected front to back and two second countersunk holes connected up and down, the second threaded hole is used to install the second screw rod, and the two second countersunk holes are used to install two second screws, each of which is threadedly connected to a T-block. The design of the second countersunk hole facilitates the installation of the second screw.

[0011] Preferably, the first screw and the second screw have the same structure, both comprising a first external thread section, a second external thread section and an external hexagonal section integrally arranged front and back, the first top and the second top are respectively threadedly connected to a section of the first external thread section, the first top seat and the second top seat are respectively threadedly connected to a section of the second external thread section, and the diameter of the second external thread section is greater than the diameter of the first external thread section. The first external thread section is used to lock the first top or the second top, the second external thread section is used to adjust the relative position of the first top and the second top, and the external hexagonal section is used to facilitate the rotation and adjustment of the first screw or the second screw.

[0012] Preferably, each of the side lift units comprises a support seat, a support nail and a side lift mechanism, wherein the support seat is fixed on the bottom plate, the support nail is vertically mounted on the support seat, and the side lift mechanism is mounted on the top of the support seat, the support nail is used to support the bottom of the double-hole casting blank, and the side lift mechanism is used to press the side of the double-hole casting blank. The positioning of the double-hole casting blank in different directions is achieved through the support seat and the side lift mechanism, thereby ensuring the reliability of the clamping of the double-hole casting blank.

[0013] Preferably, the side top mechanism comprises a side top block, a positioning block and a side top screw, the positioning block is fixed on the top of the support seat, the end face of the positioning block facing the double-hole casting blank is a first inclined surface slanting from top to bottom toward the middle of the bottom plate, a half threaded hole is provided on the first inclined surface, a second inclined surface is provided on the back side of the side top block, the second inclined surface is parallel to the first inclined surface, a half light hole and a groove are provided on the second inclined surface, the half light hole is arranged on the upper part of the second inclined surface, the half threaded hole and the half light hole are combined It is an operation hole, the groove is arranged on the lower side of the half light hole, the radius of the operation hole is smaller than the groove depth of the groove, the side top screw is a hexagon socket screw, the radial rear half of the side top screw is threadedly connected with the half threaded hole, the radial front half of the side top screw is limited in the groove, the two axial end faces of the side top screw are respectively facing the top and bottom surfaces of the groove, the front side of the side top block is used to tighten the side of the double-hole casting blank, and the side top surface is provided with a plurality of long strip grooves parallel to each other. The structure of the above-mentioned side top mechanism is simple, which is convenient for adjusting the left and right position of the side top block, so as to quickly realize the clamping operation of the side of the double-hole casting blank. When adjusting, just insert a wrench into the operating hole and rotate the side top screw to make the side top screw move obliquely along half of the threaded hole, while applying an oblique thrust or pull to the side top block, thereby realizing the left and right translation of the side top block, thereby achieving the purpose of adjusting the left and right position of the side top block, so as to better match the width size of the double-hole casting blank and improve the clamping accuracy and clamping reliability.

[0014] Preferably, the positioning block is fixed to the top of the support seat by a positioning screw, a waist-shaped hole is provided on the positioning block, the long axis of the waist-shaped hole is along the left-right direction, and the positioning screw is arranged in the waist-shaped hole. The waist-shaped hole design facilitates the left-right adjustment of the installation position of the positioning block on the support seat, thereby adjusting the distance between the side top mechanisms on the left and right sides of the bottom plate, meeting the clamping needs of double-hole casting blanks of different widths.

[0015] Furthermore, the support pin includes a square section and a threaded section integrally arranged above and below, the threaded section is threadedly connected to the support seat, the square section is provided with a plurality of through holes for a hexagonal wrench to screw the support pin, and the top surface of the square section is a support surface for supporting the bottom of the double-hole casting blank. The height of the support pin is easy to adjust, which is conducive to further improving the clamping accuracy of the double-hole casting blank.

[0016] Preferably, the support surface is a tooth surface provided with a plurality of positioning teeth to ensure that the support surface is in full contact with the double-hole casting blank, thereby achieving reliable support for the double-hole casting blank.

[0017] Compared with the prior art, the present invention has the following advantages: the fast self-centering fixture for rough machining of double-hole casting blanks of the present invention takes the front and rear butt holes of the double-hole casting blank as the reference, uses the first and second tops to center and tighten the front and rear butt holes of the double-hole casting blank, and clamps the double-hole casting blank left and right through multiple side top units, so as to realize fast clamping and fast self-centering of rough machining of double-hole casting blanks, shorten the clamping and alignment time of double-hole casting blanks, and improve the production efficiency of double-hole casting blanks. The precision requirements of each component of the fixture of the present invention are not high, the processing cost is low, it is easy to use and flexible, and it meets the clamping needs of rough machining of double-hole casting blanks of different specifications within a certain size range. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the appearance of the rapid self-centering fixture in the embodiment;

[0019] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0020] Figure 3 It is a schematic longitudinal section diagram of the structure of a single side roof unit in the embodiment;

[0021] Figure 4 for Figure 3 Enlarged view of point B in the middle;

[0022] Figure 5 This is a schematic diagram of the appearance of the bottom plate in the embodiment;

[0023] Figure 6 It is a partial sectional front view of the first top seat in the embodiment;

[0024] Figure 7 A partial cross-sectional front view of the first screw or the second screw in the embodiment;

[0025] Figure 8 This is a schematic diagram of the appearance of a single supporting pin in the embodiment;

[0026] Fig. 9 A schematic diagram of the clamping state of the bearing seat blank in the embodiment;

[0027] The specific reference numerals in the figure are as follows:

[0028] 1-bottom plate, 11-T-slot, 2-fixed side centering unit, 21-first top, 22-first top seat, 23-first screw, 24-first threaded hole, 25-first countersunk hole, 26-locating pin hole, 3-movable side centering unit, 31-second top, 32-second top seat, 33-second screw, 4-side top unit, 41-support seat, 42-support pin, 43-square segment, 44-threaded segment, 45-through hole, 46-support surface, 47-positioning teeth, 51-first external threaded section, 52-second external threaded section, 53-external hexagonal section, 61-side top block, 611-side top surface, 612-long groove, 62-positioning block, 63-side top screw, 64-positioning screw, 65-waist-shaped hole, 66-first inclined surface, 67-half threaded hole, 68-second inclined surface, 69-half light hole, 60-groove, 601-top surface, 602-bottom surface, 7-operating hole, 8-bearing seat blank. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with the embodiments of the drawings. Components or structures not limited in the present invention all adopt conventional technical means in the art.

[0030] The rapid self-centering fixture for rough machining of double-hole casting blanks of the embodiment, such as Figure 1 As shown, it includes a bottom plate 1, a fixed side centering unit 2, a movable side centering unit 3 and six side top units 4. The fixed side centering unit 2 and the movable side centering unit 3 are installed on the bottom plate 1 at intervals in front and back, and the six side top units 4 are installed on the bottom plate 1 at intervals in left and right. The fixed side centering unit 2 includes a first top 21, a first top seat 22 and a first screw 23. The first screw 23 crosses the first top seat 22 and is threadedly connected to the first top seat 22. The first top 21 is coaxially fixed to the front end of the first screw 23. The first top seat 22 is fixed on the base plate 1, the movable side centering unit 3 includes a second top point 31, a second top point seat 32 and a second screw 33, the second screw 33 crosses the second top point seat 32 and is threadedly connected with the second top point seat 32, the second top point 31 is coaxially fixed to the front end of the second screw 33, the second top point seat 32 can be slidably installed on the base plate 1, the first top point 21 and the second top point 31 are used for front and rear centering and tightening the front and rear butt holes of the double-hole casting blank to be clamped, and the six side top units 4 are used for clamping the double-hole casting blank left and right.

[0031] In this embodiment, the first top seat 22 is a trapezoidal shape with a small top and a large bottom to ensure stability; Figure 6As shown, the first top seat 22 is provided with a first threaded hole 24 connected front to back, two first countersunk holes 25 connected up and down, and two positioning pin holes 26. The first threaded hole 24 is used to install the first screw rod 23, and the two first countersunk holes 25 are used to install two first screws (not shown in the figure). The two first screws are threadedly connected to the base plate 1. Two positioning pin holes 26 are provided at the bottom of the first top seat 22. The two positioning pin holes 26 are used to install two positioning pins (not shown in the figure). The two positioning pins are positioned and connected to the base plate 1.

[0032] In this embodiment, Figure 5 As shown, two T-slots 11 are provided on the upper part of the bottom plate 1, and the two T-slots 11 are arranged in parallel on the left and right sides. Two T-blocks (not shown in the figure) are fixed to the bottom of the second top seat 32, and each T-block is slidably connected to a T-slot 11; the second top seat 32 is a trapezoid with a small top and a large bottom to ensure stability; see Figure 6 A second threaded hole communicating front to back and two second countersunk holes communicating up to and down are provided in the second top seat 32. The second threaded hole is used to install the second screw rod 33. The two second countersunk holes are used to install two second screws (not shown in the figure). Each second screw is threadedly connected to a T-block.

[0033] In this embodiment, Figure 7 As shown, the first screw 23 and the second screw 33 have the same structure, both including a first external thread segment 51, a second external thread segment 52 and an external hexagonal segment 53 integrally arranged in the front and rear, the first tip 21 and the second tip 31 are respectively threadedly connected to a section of the first external thread segment 51, the first tip seat 22 and the second tip seat 32 are respectively threadedly connected to a section of the second external thread segment 52, and the diameter of the second external thread segment 52 is larger than the diameter of the first external thread segment 51.

[0034] In this embodiment, the first tip 21, the second tip 31, the first screw 23 and the second screw 33 are all quenched as a whole to ensure hardness. The first tip 21 and the second tip 31 are both solid tips, and the overall surface only needs to be smooth.

[0035] In this embodiment, Figure 2 to Figure 4 As shown, each side top unit 4 includes a support seat 41, a support nail 42 and a side top mechanism. The support seat 41 is fixed on the bottom plate 1, the support nail 42 is vertically installed on the support seat 41, and the side top mechanism is installed on the top of the support seat 41; the support nail 42 is used to support the bottom of the double-hole casting blank, such as Figure 8As shown, the support nail 42 includes a square section 43 and a threaded section 44 which are integrally arranged in the upper and lower parts. The threaded section 44 is threadedly connected to the support seat 41. The square section 43 is provided with four through holes 45 divided by 45 degrees for a hexagonal wrench to screw the support nail 42. The top surface of the square section 43 is a support surface 46 for supporting the bottom of the double-hole casting blank. The support surface 46 is a tooth surface provided with a plurality of positioning teeth 47; the side top mechanism is used to tighten the side of the double-hole casting blank. Specifically, the side top mechanism includes a side top block 61, a positioning block 62 and a side top screw 63. The positioning block 62 is pressed and fixed on the top of the support seat 41 by the positioning screw 64. A waist-shaped hole 65 is provided on the positioning block 62. The long axis of the waist-shaped hole 65 is along the left-right direction. The positioning screw 64 is arranged in the waist-shaped hole 65. The end surface of the positioning block 62 facing the double-hole casting blank is a first inclined surface 66 which is inclined from top to bottom toward the middle of the bottom plate 1. The first inclined surface 66 A half threaded hole 67 is provided on the top, and a second inclined surface 68 is provided on the back of the side top block 61, and the second inclined surface 68 is parallel to the first inclined surface 66. A half light hole 69 and a groove 60 are provided on the second inclined surface 68, and the half light hole 69 is arranged at the upper part of the second inclined surface 68. The half threaded hole 67 and the half light hole 69 are combined into an operating hole 7, and the groove 60 is arranged at the lower side of the half light hole 69. The radius of the operating hole 7 is smaller than the groove depth of the groove 60. The side top screw 63 is a hexagon socket screw, and the radial rear half of the side top screw 63 is threadedly connected with the half threaded hole 67, and the radial front half of the side top screw 63 is limited in the groove 60. The two axial end faces of the side top screw 63 are respectively opposite to the top surface 601 and the bottom surface 602 of the groove 60. The front side of the side top block 61 is a side top surface 611 for tightening the side of the double-hole casting blank, and the side top surface 611 is provided with a plurality of long strip grooves 612 parallel to each other.

[0036] A bearing seat blank 8 is used as the clamping object, and the above-mentioned rapid self-centering fixture is used for rough processing and clamping. The effect diagram of the bearing seat blank 8 after clamping is shown in FIG. Fig. 9 .like Fig. 9 As shown, the first top 21 and the second top 31 center and tighten the front and rear butt holes of the bearing seat blank 8, and the six side top units 4 clamp the bearing seat blank 8 left and right. By rotating each support nail 42, the height of each support nail 42 can be adjusted so that the support surface 46 at the top of each support nail 42 is fully in contact with the bottom of the bearing seat blank 8; by loosening the positioning screw 64, the left and right position of the side top mechanism can be adjusted as a whole to meet the clamping needs of the bearing seat blank 8 of different widths; by rotating the side top screw 63, the side top screw 63 can be moved obliquely along the half threaded hole 67 and apply an oblique thrust or pull force to the side top block 61, thereby realizing the left and right translation of the side top block 61, and achieving the purpose of adjusting the left and right position of the side top block 61, so as to better match the width size of the bearing seat blank 8 and improve the clamping accuracy and clamping reliability.

[0037] For a single bearing seat blank 8, under the conventional clamping method of the workshop, the alignment process alone takes 10 to 20 minutes during a single clamping process, and the clamping efficiency is low. After using the rapid self-centering clamp of the present invention, the single clamping time of the bearing seat blank 8 is 2 to 5 minutes, which greatly improves the clamping efficiency, precision and reliability, and is conducive to improving production efficiency.

Claims

1. A rapid self-centering fixture for rough machining of double-hole casting blanks, characterized in that: The invention comprises a base plate, a fixed side centering unit, a movable side centering unit and a plurality of side top units, wherein the fixed side centering unit and the movable side centering unit are installed on the base plate at intervals in front and back, and the plurality of side top units are installed on the base plate at intervals in left and right. The fixed side centering unit comprises a first top, a first top seat and a first screw, the first screw crosses the first top seat and is threadedly connected to the first top seat, the first top is coaxially fixed to the front end of the first screw, and the first top seat is fixed to the base plate; the movable side centering unit comprises a second top, a second top seat and a second screw, the second screw crosses the second top seat and is threadedly connected to the second top seat, the second top is coaxially fixed to the front end of the second screw, and the second top seat can be slidably installed on the base plate front and back, the first top and the second top are used for front and rear centering and tightening the front and rear butt holes of a double-hole casting blank to be clamped, and the plurality of side top units are used for clamping the double-hole casting blank left and right.

2. According to claim 1, a rapid self-centering fixture for rough machining of double-hole casting blanks is characterized in that: The first top seat is a trapezoid that is smaller at the top and larger at the bottom. The first top seat is provided with a first threaded hole that is connected front to back, two first countersunk holes that are connected up and down, and two positioning pin holes. The first threaded hole is used to install the first screw rod, and the two first countersunk holes are used to install two first screws. The two first screws are threadedly connected to the base plate. The two positioning pin holes are provided at the bottom of the first top seat. The two positioning pin holes are used to install two positioning pins. The two positioning pins are positioned and connected to the base plate.

3. According to claim 1, a rapid self-centering fixture for rough machining of double-hole casting blanks is characterized in that: Two T-shaped slots are provided on the upper part of the bottom plate, and the two T-shaped slots are arranged in parallel on the left and right sides. Two T-shaped blocks are fixed on the bottom of the second top seat, and each of the T-shaped blocks is slidably connected to one of the T-shaped slots.

4. A rapid self-centering fixture for rough machining of double-hole casting blanks according to claim 3, characterized in that: The second top seat is a trapezoid with a small top and a large bottom. A second threaded hole connected front to back and two second countersunk holes connected up and down are opened in the second top seat. The second threaded hole is used to install the second screw rod, and the two second countersunk holes are used to install two second screws. Each of the second screws is threadedly connected to a T-block.

5. According to claim 1, a rapid self-centering fixture for rough machining of double-hole casting blanks is characterized in that: The first screw and the second screw have the same structure, and both include a first external thread segment, a second external thread segment and an external hexagonal segment that are integrally arranged in the front and rear, the first top and the second top are respectively threadedly connected to a segment of the first external thread segment, the first top seat and the second top seat are respectively threadedly connected to a segment of the second external thread segment, and the diameter of the second external thread segment is larger than the diameter of the first external thread segment.

6. A rapid self-centering fixture for rough machining of double-hole casting blanks according to claim 1, characterized in that: Each of the side top units includes a support seat, a support nail and a side top mechanism, the support seat is fixed on the base plate, the support nail is vertically installed on the support seat, and the side top mechanism is installed on the top of the support seat. The support nail is used to support the bottom of the double-hole casting blank, and the side top mechanism is used to tighten the side of the double-hole casting blank.

7. A rapid self-centering fixture for rough machining of double-hole casting blanks according to claim 6, characterized in that: The side top mechanism includes a side top block, a positioning block and a side top screw, the positioning block is fixed on the top of the support seat, the end face of the positioning block facing the double-hole casting blank is a first inclined surface slanting from top to bottom toward the middle of the bottom plate, and a half threaded hole is provided on the first inclined surface. The back of the side top block is provided with a second inclined surface, and the second inclined surface is parallel to the first inclined surface. A half light hole and a groove are provided on the second inclined surface, and the half light hole is arranged on the upper part of the second inclined surface. The half threaded hole and the half light hole are combined into one An operating hole, wherein the groove is arranged on the lower side of the half light hole, the radius of the operating hole is smaller than the groove depth of the groove, the side top screw is a hexagon socket screw, the radial rear half of the side top screw is threadedly connected to the half threaded hole, the radial front half of the side top screw is limited in the groove, the two axial end faces of the side top screw are respectively opposite to the top and bottom faces of the groove, the front face of the side top block is the side top face for tightening the side face of the double-hole casting blank, and a plurality of long strip grooves parallel to each other are arranged on the side top face.

8. A rapid self-centering fixture for rough machining of double-hole casting blanks according to claim 7, characterized in that: The positioning block is fixed to the top of the support seat by means of a positioning screw. A waist-shaped hole is provided on the positioning block. The long axis of the waist-shaped hole is along the left-right direction. The positioning screw is arranged in the waist-shaped hole.

9. A rapid self-centering fixture for rough machining of double-hole casting blanks according to claim 6, characterized in that: The support nail includes a square section and a threaded section integrally arranged above and below, the threaded section is threadedly connected to the support seat, the square section is provided with a plurality of through holes for a hexagonal wrench to screw the support nail, and the top surface of the square section is a supporting surface for supporting the bottom of the double-hole casting blank.

10. A rapid self-centering fixture for rough machining of double-hole casting blanks according to claim 9, characterized in that: The supporting surface is a tooth surface provided with a plurality of positioning teeth.

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