46 results about "Ball diameter" patented technology

To provide a deep groove ball bearing that eliminates a load on a holder caused by advance / delay of a ball, and eliminates interference between the holder and an outer diameter surface of an inner ring, and between the holder and an inner diameter surface of an outer ring.SOLUTION: A deep groove ball bearing comprises an inner ring having an inner ring raceway surface on an outer periphery, an outer ring having an outer ring raceway surface on an inner periphery, a plurality of balls 4 rolling between the inner ring raceway surface and the outer ring raceway surface, and a holder 5 holding the balls 4 at regular intervals in a circumferential direction, where a lower limit value of a circumferential pocket gap formed between a pocket 50 of the holder 5 that houses the ball 4 and the ball 4 is set to 0.1 mm, and an upper limit thereof to [0.09×used ball diameter-0.007] (mm).SELECTED DRAWING: Figure 6

A method of designing a ball bearing includes providing a value of a shaft outside diameter and a load. An inside diameter of a bearing inner ring is determined based on the value of the shaft outside diameter. A ball size having a specific ball diameter is selected and a number of the balls of the selected standard ball size required to support the load is determined. A pitch diameter of a pitch circle of the ball bearing is determined based on the determined number of balls of the selected ball size. A suitability factor is calculated for the particular value of the pitch diameter and the particular pitch diameter is validated as suitable when the suitability factor is between calculated upper and lower limits.

The invention provides a method for determining the ball diameter and grading of an ore grinding medium in fine grinding operation, which adopts two or more ore grinding medium ball diameter theoretical calculation methods, and comprises the following steps: calculating the theoretical ball diameter of the ore grinding medium of each size fraction of materials to be ground, and preliminarily determining the ball diameter and ball ratio of a mill by referring to the granularity composition and mass fraction of the materials to be ground; and then verifying and optimizing through an ore grinding test, and finally determining the technical scheme of reasonable initial ball loading and accurate ball supplementing and adding of the mill. The method comprises the steps of size fraction analysis and grouping of the materials to be ground, theoretical ball diameter calculation, ore grinding test verification, determination of the initial ball loading scheme of the mill and determination of the ball supplementing and adding scheme of the mill, theoretical calculation and test verification optimization are included, the implementation method is simple, the application range is wide, and the process effect is good.

A linear guide (10) comprises: a guide rail (1) having a raceway groove (3) on a side surface; a slider (2) assembled to the guide rail (1) and having a raceway groove (7) facing the raceway groove (3); and a plurality of rolling elements disposed rollably in a rolling element rolling path (23), which is composed of a load rolling path (22) formed by the raceway grooves (3, 7), and a no-load rolling path (21) provided on the slider (2) and communicating between one end and the other end of the load rolling path (22). One of the guide rail (1) and the slider (2) moves relative to the other as the rolling elements roll. The plurality of rolling elements are constituted by a plurality of steel balls (6), and a plurality of spacer balls (16) smaller than the steel balls (6) and having elasticity. At least one spacer ball (16) is always present in the no-load rolling path (21). The length of a gap in which neither the steel balls (6) nor the spacer balls (16) are present in the rolling element rolling path (23) is 50% or less of the diameter of the steel balls (6), regardless of the position of the rolling elements. Consequently, it is possible to provide a rolling guide device that is easy to assemble and has good operability and excellent repeated positioning accuracy.

An angular contact ball bearing has: an inner ring having a cross-sectional circular-arc-shaped inner ring raceway groove on an outer peripheral surface; an outer ring having a cross-sectional circular-arc-shaped outer ring raceway groove on an inner peripheral surface; and a plurality of balls disposed freely rolling between the inner ring raceway groove and the outer ring raceway groove. A ratio (Ri) of a groove curvature radius of the inner ring raceway groove to a ball diameter is 54 to 58%, a ratio (Ro) of a groove curvature radius of the outer ring raceway groove to the ball diameter is 51 to 58%, and Ri-Ro is 0% or more, and at least the inner ring raceway groove has a maximum surface pressure of 4.7 to 6.0 GPa when a sum of permanent deformations of the ball and the inner ring raceway groove at a center of a contact portion of the ball and the inner ring raceway groove is one ten-thousandth of the ball diameter. Thus, an angular contact ball bearing capable of reducing a heat generation amount and suppressing damage caused by an external impact load at a standstill is provided.

The application discloses a bearing steel ball grinding tool, a parameter design method and a use method, and mainly relates to the bearing machining technical field. The bearing steel ball grinding tool comprises a fixed grinding disc and a movable grinding disc arranged at the bottom of the fixed grinding disc. The top of the movable grinding disc and the bottom of the fixed grinding disc are both provided with annular V-shaped grooves. The angle of the tip of the V-shaped groove is 90 degrees. Circular arc grooves are arranged on the two inner walls of the V-shaped groove. The center point of the circular arc groove is a pure rolling point of the steel ball. The bisector of the angle formed by the connecting line of the center points of the two circular arc grooves and the center of the steel ball coincides with the center line of the V-shaped groove. The application can effectively improve the coverage of the grinding tool grinding track network on the surface of the steel ball, effectively reduce the spherical deviation and the spherical diameter variation of the steel ball after grinding, and improve the final grinding precision.

To provide a ball bearing which can optimize the diameters of a plurality of balls with different sizes as a roller and which can contribute to reduction in rotation torque and increase in acceptable load.SOLUTION: A representative configuration of a ball bearing 100 includes: an outer ring 110; an inner ring 120; and a plurality of balls that roll between the outer ring and the inner ring. As the balls, balls with different diameters are regularly aligned. When a parameter γ representing an internal configuration of the bearing is indicated by the following formula: γ=(Da / PCD)*cosα (where Da is the diameter of the ball, PCD is a pitch circle diameter, and α is a contact angle), a maximum ball diameter difference ΔDa between a ball with the largest diameter (largest-diameter ball 132) and a ball with the smallest diameter (smallest-diameter ball 134) is within a range of (7.52×10-4γ+8.91×10-4)*Da≤ΔDa≤(6.43×10-3γ+7.62×10-3)*Da when γ≤0.09, and (-9.65×10-4γ+1.05×10-3)*Da≤ΔDa≤(-8.25×10-3γ+8.98×10-3)*Da when γ>0.09.SELECTED DRAWING: Figure 2

The invention discloses hub bearing ball double-channel assembling equipment, and belongs to the field of assembling equipment. Comprising a workbench, a mounting cover is arranged on the workbench, and the mounting cover is provided with an auxiliary plate; the feeding assembly is arranged on the auxiliary plate; the rotating assembly is arranged on the workbench; the moving assembly is arranged on the workbench; and the adjusting assembly is arranged on the supporting part, and the adjusting assembly is arranged on the supporting part. According to the hub bearing ball double-channel assembling equipment, through double-channel feeding of the feeding assembly, the conveying part and the sensing part, efficient conveying of balls is achieved; the rotating assembly drives the holder to stably rotate, and the moving assembly accurately positions the material conveying part; the adjusting assembly dynamically adjusts the assembling clearance, the fine adjustment part controls the distance, the difference value between the distance and the ball diameter is reduced, vibration is restrained, ball deviation is reduced, manual adjustment is not needed, intervention is reduced, and the assembling efficiency and precision are improved.

An apparatus for picking up, holding and transporting one or more balls. The apparatus has two rectangular frame members positioned parallel and opposite each other. Tensioning arrangement connect between corresponding corner segments of the frame members. In an unstretched position of the tensioning arrangement the frame members are distanced a distance that is smaller than a ball diameter. When picking up a ball, the frame members are distanced a distance that is equal to the ball diameter, and, after picking up the ball, the frame members are distanced a distance that is smaller than the ball diameter and larger than the unstretched distance, and, the ball is retained within the apparatus.

To provide a combined angular contact ball bearing for a compressor capable of preventing slippage between a ball and a raceway surface of an inner ring or outer ring even when subjected to abrupt load fluctuation and rotational fluctuation.SOLUTION: A combined angular contact ball bearing (1) for a compressor supports a rotational shaft of the compressor, and comprises: one or more first bearings (2) that receive a load in a first direction (D1) along an axial core direction while the compressor is operating; and one or more second bearings (3) that receive a load in a second direction (D2) opposite to the first direction (D1) when the compressor is stopped. A ball diameter (BD2) of the second bearing (3) is smaller than a ball diameter (BD1) of the first bearing (1).SELECTED DRAWING: Figure 1

The utility model discloses a cleaning device, which is used for cleaning grinding balls after quenching and before tempering, and comprises a plate body, one or more first channel sections allowing the grinding balls to pass through are arranged on the obliquely arranged plate body, a plurality of first channel sections are arranged in parallel, and a plurality of corners are arranged in the first channel sections. The plate body is provided with a ball inlet groove body communicated with inlets above all the first channel sections and a ball outlet groove body directly or indirectly communicated with outlets below all the first channel sections, the plate body is provided with a first containing groove section, an opening is formed in the lower portion of the first containing groove section, and a plurality of balls are arranged in the first containing groove section in an array mode. The column spacing of the plurality of balls is matched with the passing of the grinding balls, the line spacing of the plurality of balls is smaller than the diameter of the grinding balls, and a first channel section is formed between any two adjacent columns of balls. The device can effectively remove quenching media on the surfaces of the grinding balls and reduce tempering oil smoke.

The utility model provides a tool for measuring the ball diameter of a steel structure welding ball, which relates to the technical field of spherical steel grid structures and comprises two groups of clamping jaw mechanisms and a positioning mechanism which are symmetrically arranged, the upper ends of the two groups of clamping jaw mechanisms are hinged through a connecting seat, and the lower ends of the two groups of clamping jaw mechanisms abut against the two ends of the ball diameter of the welding ball. The device is good in measurement effect and reliable in mode, can effectively overcome the distinguishing of size specifications of stacking, splicing and model selection of the welding balls on site and the inspection of the diameter sizes of the welding balls on the site, also ensures the inspection of the quality of the welding balls on the site, avoids quality flaws and potential safety hazards, and improves the production efficiency. In addition, the ball diameter measuring device is simple and convenient to operate and high in popularization value.

The present invention makes it possible to realize a bearing that can be applied under high-speed rotation conditions. In this ball bearing, when Da represents the ball diameter, D represents the bearing outer diameter, d represents the bearing inner diameter, and PCD represents the pitch circle diameter of a ball (5), the minimum wall thickness t in the axial direction of an annular part (11) at the bottom of a pocket (12) is 15-30% of the ball diameter Da, the bearing inner diameter d is 25-55 mm, the bearing outer diameter D is 50-90 mm, the bearing width H is 10-20 mm, the ball diameter Da is 7 / 32 inches or less, and the ratio of the value that is specified by 1 / 2 of the difference between the pitch circle diameter PCD and the bearing inner diameter d with respect to the bearing inner diameter d is 10-20%.

A groove curvature radius ratio Ri of the inner ring raceway groove to a ball diameter is 54% to 58%, a groove curvature radius ratio Ro of an outer ring raceway groove of an outer ring to the ball diameter is 51% to 58%, and Ri−Ro≥0 points. At least an inner ring raceway groove of an inner ring has a maximum surface pressure of 4.7 GPa to 6.0 GPa when a sum of permanent deformation amounts of the ball and the inner ring raceway groove at a center of a contact portion between a ball of an angular ball bearing and the inner ring raceway groove is 1 / 10,000 of the ball diameter. Accordingly, it is possible to provide the angular ball bearing that can reduce the heat generation amount, and that can reduce the damage caused by the external impact load in the stationary state.

The utility model provides a ball pin ball diameter automatic detection device, comprising a frame and a loading manipulator connected to the frame, a ball diameter detection component, an appearance detection component, a defective product removal component, a defective product storage component and a unloading manipulator; the frame is connected to a turntable component, and the turntable component is connected to a plurality of supporting fixtures; the loading manipulator is used for placing the ball pin to be inspected on the supporting fixture, the ball diameter detection component is used for detecting the ball diameter of the ball pin located on the supporting fixture, the appearance detection component is used for detecting the appearance of the ball pin located on the supporting fixture, the defective product removal component is used for placing the ball pin that fails the inspection into the defective product storage component, and the unloading manipulator is used for placing the ball pin into the unloading basket; the utility model can automatically realize the inspection of the ball diameter and appearance of the ball pin in a mechanized manner, thereby having the advantages of high ball pin inspection accuracy and high inspection efficiency, and can save labor costs.

A self-aligning bearing for adjusting a crane trolley and an end beam comprises a bearing body, the bearing body comprises an annular supporting inner ring and further comprises a supporting outer ring arranged on the outer side of the supporting inner ring, an eccentric supporting ring is arranged between the supporting outer ring and the supporting inner ring, and inner balls are arranged between the inner side of the eccentric supporting ring and the outer side of the supporting inner ring. Outer balls are arranged between the outer side of the eccentric supporting ring and the inner side of the outer supporting ring, the inner side of the eccentric supporting ring is in a circular ring shape, the outer side of the eccentric supporting ring is in an eccentric arc shape, and the ball diameter of the outer balls is larger than that of the inner balls. The device is simple in structure and convenient to use.

To provide a ball screw design method and a ball screw that can secure smooth ball movement and cope with high speed movement.SOLUTION: In a ball screw design method, when a ball diameter is represented as Da, the length of a straight line between two curved lines as L, a ball pitch angle on the curved line as θb, and a central angle of the curved line as θr in the case where there exists a straight line between the two curved lines whose radiuses are the same as a central line of a circuit, an angle ratio of the curved lines is defined as θr / θb, and the θr / θb is determined as (A) θr / θb≒n+0.25 (n being an optional integer), or (B) when θr / θb≒n+0.25 is not satisfied, the value of L is set so as to satisfy formulas (1) and (2): (1) L / Da+θr / θb≒n+0.5 (n being an integer), (2) L≒(n+0.5-(θr / θb))×Da.SELECTED DRAWING: Figure 4

The invention provides a falling ball testing device, and the device comprises an objective table which is used for bearing a to-be-detected object; the lifting part is connected with the objective table; the ball falling mechanism comprises a placing table and a supporting frame, the supporting frame is installed on the lifting part, and the placing table is arranged above the objective table through the supporting frame; wherein the placing table comprises a placing surface used for bearing the falling balls, and the placing table is movably installed on the supporting frame so as to release the falling balls. According to the falling ball testing device provided by the invention, the placement surface of which the bottom is used for supporting the falling balls is adopted, so that the falling balls made of various materials such as magnetic and non-magnetic materials can be compatible, and the defect that an electromagnetic adsorption mode is limited for testing the materials is overcome; after falling balls with different diameters are placed through the placing surface, the impact heights of the falling balls relative to the objective table are consistent, so that test errors caused by diameter changes of the falling balls are eliminated; therefore, the accuracy, the applicability and the reliability of the test are improved.

Externally mounted ball screw, featuring: • a spindle shaft (10), • a screw nut (20) which can be placed on the spindle shaft (10) and is provided with a through hole (24) with an opening edge (241) which is continuously connected by a ball path (T1) which is arranged between the screw nut (20) and the spindle shaft (10), • several bearing balls (30) which can roll along the ball path (T1), wherein the diameters of the bearing balls (30) are defined as ball diameters (BD), and • a rotating component (40) connected to the screw nut (20) and provided with a running groove (41) which is continuously connected to the through hole (24) and is formed with a pivot segment (411) connected thereto, wherein the end of the pivot segment (411) connected to the through hole (24) is formed with a coupling edge (411A) which presses against the opening edge (241), wherein the connection of the opening edge (241) to the coupling edge (411A) is not arranged tangentially, wherein the pivot segment (411) can rotate about a reference point (A) and the outer wall surface (411B) of the pivot segment (411) is arc-shaped with this reference point (A) as the center of a circle, which is located away from the outer wall surface (411B) by a radius of curvature (R), wherein the radius of curvature (R) is greater than or equal to the 1.2 times the diameter of a sphere (BD) or less than or equal to 1.5 times the diameter of a sphere (BD).

This invention discloses a table tennis serving device, characterized by comprising a pair of compression wheels arranged side-by-side at the end of the ball delivery channel. The middle of the compression wheels is positioned directly opposite the center of the ball delivery channel. The compression wheels are connected to a compression motor and can be driven to rotate outwards relative to each other, forming a launch port on the outer side of the compression wheels. The distance between the side-by-side compression wheels is smaller than the diameter of the table tennis ball, and the difference between the two is smaller than the compression deformation limit of the compression wheels and the table tennis ball. This method relies on the relative rotation of the compression wheels to impart launch speed to the table tennis ball, achieving a mechanical serving effect without noise or interference from airflow, avoiding the drawbacks of pneumatic serving and making it more suitable for live ball training.

The invention relates to an impeller receptacle, in particular for an impeller of a fan, comprising at least one rotationally symmetrical body. The rotationally symmetrical body has a first end face, a second end face and a lateral face, wherein at least one radial bore extends radially from the lateral face into the rotationally symmetrical body and an assembly recess extends from the first end face into the radial bore. A detent ball having a ball diameter and a spring are arranged in the at least one radial bore, wherein the detent ball can be pressed radially outwards by means of the spring. The radial bore has at least one first, inner radial bore diameter and a second, outer radial bore diameter, the second, outer radial bore diameter being smaller than the ball diameter.

The T-shaped inner ring bearing capable of enhancing the load comprises an outer ring, an inner ring, a retainer, a sealing ring and a steel ball, and annular protrusions are arranged on the peripheries of the two axial ends of the inner ring respectively; the outer diameter of the outer ring is 119.2 mm, and the axial thickness of the outer ring is 34 mm; the inner diameter of the inner ring is 55 mm, the axial thickness of the inner ring is 30 mm, the axial height of the annular protrusion is 2.5 mm, and the inner diameter of the inner side of the annular protrusion is 70.2 mm. And the radius of the annular channel of the outer ring and the inner ring is 6mm. The bearing has the advantages that the structure is changed into a double-row-ball structure, the diameter of the steel balls is reduced, the number of the steel balls is increased, and the bearing capacity of the bearing is improved by fully utilizing the mounting height of the inner ring and increasing the wall thickness of the ferrule; according to the T-shaped inner ring double-row ball structure, the two ends of the outer circle of the inner ring extend outwards to form the bosses, the diameter of the rolling body is increased, the load of the optimal design is increased, and all design advance elements are met.

Provided are a ball screw designing method and a ball screw capable of ensuring smooth movement of balls and of accommodating an increase in speed. This ball screw designing method involves, in a case where a straight line exists between two curves having equal radii as the center line of a circulation path, setting the value of L so as to satisfy formulae (1) and (2) where Da represents the ball diameter, L represents the length of the straight line between the two curves, θb represents the ball pitch angle on the curves, θr represents the center angle of the curves, and the angle ratio of the curves is defined as θr / θb, when (A) θr / θb ≈ n+0.25 (n is an arbitrarily-defined integer) is satisfied or (B) θr / θb ≈ n+0.25 is not satisfied.　(1): L / Da+θr / θb ≈ n+ 0.5 (n is an integer) (2): L ≈ (n+0.5-(θr / θb))×Da

A deep groove ball bearing is disclosed, comprising an outer ring, an inner ring, balls arranged between the outer and inner rings, and a cage for holding the balls. The outer ring has an outer raceway, the outer raceway defines an outer raceway radius, the ratio of the outer raceway radius to the diameter of the balls defines a first ratio, and two edges of the outer raceway in the axial direction define an outer raceway boundary angle relative to the center of the arc of the outer raceway. The inner ring has an inner raceway, the inner raceway defines an inner raceway radius, the ratio of the inner raceway radius to the diameter of the balls defines a second ratio, and two edges of the inner raceway in the axial direction define an inner raceway boundary angle relative to the center of the arc of the inner raceway.The range of the first ratio is 0.525 - 0.570, the range of the second ratio is 0.510 - 0.530, the range of the outer ring raceway limit angle is 66° - 97°, and the range of the inner ring raceway limit angle is 72° - 99°. Compared to the prior art, the deep groove ball bearing exhibits a significantly reduced frictional torque.

The utility model belongs to the technical field of steel ball detection, and particularly relates to a wear-resistant steel ball diameter rapid measuring device which comprises an objective table, a distance measuring assembly, a blanking assembly and a storage assembly, the distance measuring assembly is arranged on the objective table, the feeding end of the blanking assembly is communicated with the objective table, and the storage assembly is communicated with the discharging end of the blanking assembly; the distance measuring assembly comprises a fixed plate, a movable plate and a distance sensor embedded in the fixed plate, the fixed plate and the movable plate are oppositely arranged on the two sides of a steel ball to be measured, and the movable plate is movably connected with the objective table through a guide rail pair.

A ball bearing having a pair of raceways composed of an inner race and an outer race, a plurality of balls interposed between raceway surfaces of the pair of raceways, and a retainer that retains the plurality of balls between the pair of raceways, the ball bearing being used in a liquefied gas. The retainer is guided by the inner race, the retainer is rotated by bringing an inner diameter surface of the retainer into sliding contact with an outer diameter surface of the inner race in a manner that a radial gap is determined, and the guide gap of the outer diameter surface of the inner race from the inner diameter surface of the retainer is 3% to 10% of a diameter of the ball, i.e., a ball diameter.

The invention relates to the technical field of turning devices, and provides a turning device for a part with an inner spherical surface and an outer spherical surface, which can realize processing operation of a spherical cavity, is better in applicability, more flexible in cutting operation, simpler in tool replacement, quicker in sphere diameter adjustment of the spherical cavity and better in practicability, and comprises a tool rest and a lathe bed, a left power box and a right power box are arranged at the left end and the right end of the lathe bed respectively, a left chuck is installed on the left power box, a left power structure used for driving the left chuck is installed in the left power box, an inner spherical surface turning assembly is installed on the left chuck and comprises a clamping frame, and the clamping frame is installed in the left chuck in a clamped mode. A centrifugal frame is rotationally connected into the clamping frame, an adjusting arm is installed on the centrifugal frame, a round-edge cutter is connected into the adjusting arm through an inserting rod frame, and a double-positioning piece is installed in the adjusting arm and used for auxiliary positioning of the round-edge cutter in the adjusting arm and auxiliary positioning of the adjusting arm relative to the centrifugal frame.

A ball seat assembly (2) for a downhole tool comprises a collet (6) having a collet shank (8) with an inner collet shank wall (36) and an outer collet shank wall, and collet fingers (10) arranged around a central axis (12) of the collet shank (8) and 5 attached to an uphole end (14) of the collet shank (8); an inner sleeve (34) configured to be axially movable along the inner collet shank wall (36), the inner sleeve (34) having a ball seat (40) and a central flow channel (42) extending through the ball seat (40); wherein the collet fingers (10) have a neutral position creating an uphole opening (26) having a first diameter (D1) and are expandable to 10 a second diameter (D2) larger than the first diameter (D1); wherein in a run-in state of the downhole tool, the inner sleeve (34) is in a first axial position relative to the collet shank (8), in which first position the inner sleeve (34) urges the collet fingers (10) to expand to the second diameter (D2) to allow a ball (44) having a ball diameter (d) less than the second diameter (D2) and larger than the first diameter 15 (D1) to pass through the uphole opening (26) of the collet (6); wherein the inner sleeve (34) is configured to move into a second axial position upon a fluid pressure applied uphole and acting against the ball (44) covering the ball seat (40) and the central flow channel (42), and wherein the ball seat assembly (2) is configured to let the collet fingers (10) snap back into the neutral position, thereby preventing the 20 ball (44) from leaving the collet (6).

Device for setting up a loudspeaker housing, comprising (a) an elongated foot bar (1) which can be attached to the front and rear walls of the loudspeaker enclosure. (b) Fastening means (4) which force-fit the foot bolt to the front and rear wall and optionally provide a positive engagement in a transverse groove (3) of the front and / or rear wall, (c) wherein the fastening means engage screw-typely on countermeasures arranged in the housing structure, in particular on (i) a transverse nut (5) in the side wall of the housing, and / or (ii) Threaded inserts or counter-screw parts in the front or rear panel, (d) a threaded stud (6) with external thread which is screwed into a fine-thread internal bore of the foot bolt and which is adjustable from above by means of a drive engagement, (e) wherein the threaded pin has a conical surface (6a) on its outer side as a contact surface and a ball sleeve (7) inserted into the base is arranged below the pin, which accommodates three balls (8) on a circumferential circle with 120° divisions, (f) wherein each sphere is in contact with the conical surface, a base support of the sphere sleeve and a cylindrical inner wall of the sphere sleeve, (g) wherein the ball sleeve (7) is encapsulated and sealed and forms a lubricant reservoir (10), (h) wherein the force flow into the foot rail, when loads occur about the transverse axis, passes through the side walls, provided that the countermeasures of the foot rail fixing screws include a transverse nut in the side wall. (i) wherein the ball sleeve has an outer diameter D in the range of 10 mm to 20 mm and the ball diameters d K are chosen proportionally to D with a ratio of 0.30 ≤ d K / D ≤ 0.35 (j) and wherein the threaded pin has an axial internal thread for receiving a countersunk screw of nominal size M3 to M5 (11) acting from above, by which the pin is clamped against the foot bolt.

This invention provides a multi-stage ball-drop optimization method and apparatus, belonging to the field of oil and gas reservoir fracturing. The method first obtains perforation diameter variation curves and perforation friction variation curves experimentally. Then, it uses these curves to determine the optimized number of ball-drop stages, the number of balls dropped, and the diameter of the temporary plugging ball. This invention effectively solves the problem of insufficient optimization methods for the number of plugging stages, the number of balls dropped, and the diameter of the temporary plugging ball in ball-drop temporary plugging fracturing, thus helping to improve the effectiveness of ball-drop temporary plugging fracturing.