Variable curvature tube inner surface polishing apparatus and method

Abstract

The application discloses a variable-curvature pipe inner surface polishing device and method, and belongs to the field of inner surface polishing.The device comprises a mechanical arm, a flexible pneumatic rubber pipe, a rubber pipe support bone joint, a four-position four-way electromagnetic valve, a distance control device, a pressure sensor and a polishing belt.The polishing device is connected by multiple bone joints, so that the flexibility of the whole device is controllable.The position of the flexible pneumatic rubber pipe support joint and the curvature of the bending at the support joint are changed by adjusting the horizontal and vertical positions of the rubber pipe support bone joint and changing the pressure of the compressed gas in the pneumatic passage, so that the flexible pneumatic rubber pipe can be attached to the shape of the inner surface of the variable-curvature pipe, and the problem that the traditional polishing device cannot effectively adapt to and polish the inner surface of the variable-curvature pipe is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of inner surface polishing, in particular to a variable curvature pipe inner surface polishing device and method. BACKGROUND

[0002] In recent years, with the development of mechanical and photoelectric products towards miniaturization and high standardization, high-precision and high-complexity parts are widely used, such as medical equipment, military-grade special equipment, aerospace equipment, etc. The high quality requirement of the surface of the parts puts forward higher requirements for the polishing processing technology of the inner surface of the parts, such as variable diameter elbow, slender nozzle, arc pipeline, variable curvature bending die and other complex parts. These parts not only have the characteristics of complex shape and high hardness and brittleness, but also the cast pipe is relatively rough, and even some parts have burrs, slag and other residues, which need to be cleaned. Otherwise, it will affect the normal use of the pipe. At present, the polishing of the inner surface of the pipe mostly adopts the traditional polishing method, such as honing, grinding and other polishing methods, which can only polish the surface of specific workpieces. And using mechanical tools such as grinding wheel machine or angle grinder, the labor intensity is large, the production efficiency is low, and it can only be applied to some simple inner surface structure of the pipe. In the face of some variable curvature and irregular pipe inner surface, the traditional mechanical tools and methods cannot meet the needs of high-quality users for roughness. In order to better deal with the polishing of the inner surface of the variable curvature pipe, it is particularly important to overcome the above problems. SUMMARY

[0003] The present application provides a variable curvature pipe inner surface polishing device and method, three flexible polishing chains are composed of flexible pneumatic rubber pipes and support bones, which are arranged uniformly on the connecting disc, and the flexible polishing chains are rotated by the mechanical arm, the cooperation of the pressure sensor and the distance control device is utilized to improve the fitting effect with the complex variable curvature pipe inner surface, and high-efficiency polishing of the pipe inner surface is realized; the concave bending flexible pneumatic rubber pipe bends downward when inflated, and the convex bending flexible pneumatic rubber pipe bends upward when inflated; the concave bending flexible pneumatic rubber pipe and the convex bending flexible pneumatic rubber pipe are arranged in pairs and in parallel on the three flexible polishing chains; the distance between the rubber pipe movable support and the sliding groove can be adjusted by the sliding groove hinge, and the position sensor is installed on the rubber pipe support bone to feedback the distance between the rubber pipe movable support and the position sensor in real time; the mechanical arm has multiple degrees of freedom to improve the spatial adaptability of the polishing device, and the position and posture of the entire polishing device can be adjusted by driving the three flexible polishing chains with the mechanical arm, which is suitable for more complex space, and according to the different inner surface bending conditions of the variable curvature pipe, the flexible polishing chain can accurately fit the inner surface of the variable curvature pipe to complete the high-efficiency and high-quality polishing processing of the inner surface of the variable curvature pipe.

[0004] The application provides a variable curvature pipe inner surface polishing device, which comprises a mechanical arm, three flexible polishing chains, a threaded connection between the end of the mechanical arm and a connecting disc, and a hinge connection between the three flexible polishing chains and the connecting disc, wherein each polishing chain of the three flexible polishing chains is composed of 10 joint units, and the joint unit comprises a four-position four-way electromagnetic valve, an axial rolling bearing, a rubber tube movable support, a concave curved flexible pneumatic rubber tube, a convex curved flexible pneumatic rubber tube, a pressure sensor, a polishing belt, a rubber tube connecting hinge fixing plate, a rubber tube connecting hinge, an electromagnetic valve fixing base, a joint side hinge, a rubber tube supporting joint, a joint hinge, a rubber tube fixing support and a distance control device, the rubber tube supporting joint is connected through the joint hinge, one side of the rubber tube connecting hinge fixing plate is fixed with the four-position four-way electromagnetic valve through the electromagnetic valve fixing base, and the other side is fixed on the rubber tube connecting hinge, one side of the concave curved flexible pneumatic rubber tube and the convex curved flexible pneumatic rubber tube is fixed on the rubber tube connecting hinge fixing plate through a threaded connection, and the other side is connected with the four-position four-way electromagnetic valve through a pneumatic hose, the joint units are sequentially connected through the rubber tube connecting hinge, the pressure sensor is attached to the outer ring surface of the rubber tube movable support and the outer ring surface of the rubber tube fixing support, the polishing belt is attached to the outer side of the axial rolling bearing, the rubber tube fixing support and the rubber tube supporting joint are connected through a spherical hinge, and the distance control device comprises a support spring, a longitudinal upper end electromagnet, a longitudinal lower end electromagnet, a sliding groove, an upper end gear rack, a sliding groove hinge, a backstop, a horizontal left end electromagnet, a position sensor, a horizontal right end electromagnet and a lower end gear rack, the rubber tube movable support is provided with the longitudinal upper end electromagnet, the rubber tube supporting joint is fixed with the upper end gear rack and the lower end gear rack through a threaded connection, and one side is provided with the position sensor and the horizontal right end electromagnet, one end of the support spring is fixed on the rubber tube movable support through a threaded connection, and the other end is fixed on the rubber tube supporting joint, the sliding groove is provided with the longitudinal lower end electromagnet and the horizontal left end electromagnet, the sliding groove is connected with the rubber tube movable support through the sliding groove hinge, the backstop comprises a backstop outer ring, a backstop inner ring, a backstop spring and a backstop hinge, the backstop inner ring and the backstop hinge are fixedly connected through a connecting pin, one end of the backstop spring is fixed on the backstop hinge through a threaded connection, and the other end is fixed on the backstop inner ring, and the backstop inner ring is in interference fit with the rubber tube movable support.

[0005] The application further provides a processing method of the variable curvature pipe inner surface polishing device.

[0006] (1) the three flexible polishing chains (1-2) are fixed on the mechanical arm (1-1) through the connecting disc (2-1), and the mechanical arm (1-1) drives the three flexible polishing chains (1-2) to enter the variable curvature pipe;

[0007] (2) Control the air pressure driving device, through the four-position four-way electromagnetic valve (3-1) to the convex type bending flexible air pressure rubber pipe (3-5) on 10 bone unit (2-3) into the compressed gas, drive three flexible polishing chain (1-2) in the variable curvature pipe inner surface realizes the preliminary bending fit;

[0008] (3) Pressure sensor (3-6) will three flexible polishing chain (1-2) fit in the variable curvature pipe inner surface pressure feedback to the control system, if the pressure sensor (3-6) shows the pressure is higher than the target value, control the horizontal left end electromagnet (4-8) and horizontal right end electromagnet (4-10) into the current mode two (8-2), at this time the horizontal left end electromagnet (4-8) right end and horizontal right end electromagnet (4-10) left end with the same charge, produce repulsion, drive the rubber pipe movable support (3-3) axial movement, if the pressure sensor (3-6) shows the pressure is lower than the target value, the control system drives the four-position four-way electromagnetic valve (3-1) to change the air pressure passage, drive the concave type bending flexible air pressure rubber pipe (3-4) bending, control the longitudinal upper end electromagnet (4-2) and longitudinal lower end electromagnet (4-3) into the current mode three (8-3), at this time the longitudinal upper end electromagnet (4-2) lower end and longitudinal lower end electromagnet (4-3) upper end with different charge, produce attraction, drive the rubber pipe movable support (3-3) reverse axial movement, at the same time regulate the size of the air pressure in the air pressure passage, can change the convex type bending flexible air pressure rubber pipe (3-5) bending fulcrum position and bending degree, can form U type flexible polishing chain (6-1), sine type flexible polishing chain (6-2) and ladder type flexible polishing chain (6-3), finally make the polishing belt (3-7) and variable curvature pipe inner surface contact area pressure constant, realize the constant force efficient polishing processing to the complex variable curvature pipe inner surface;

[0009] (4) Control the left end electromagnetic (4-8) and the right end electromagnetic (4-10) into the current mode one (8-1), at this time the left end electromagnetic (4-8) right end and the right end electromagnetic (4-10) left end with heterotypic charge, produce attractive force, make the chute (4-4) drive rubber tube movable support (3-3) move to the direction of position sensor (4-9), namely positive right movement, the position sensor (4-9) detects the rubber tube movable support (3-3) moves to the target position, control the left end electromagnetic (4-8) and the right end electromagnetic (4-10) into the current mode two (8-2), at this time the left end electromagnetic (4-8) right end and the right end electromagnetic (4-10) left end with the same charge, produce repulsive force, at the same time support spring (4-1) generates the reverse left return force to the rubber tube movable support (3-3), check valve (4-7) limits the rubber tube movable support (3-3) reverse left return, makes the rubber tube movable support (3-3) fixed in the target position, guarantees the stability of the formed U type flexible polishing chain (6-1), sinusoidal flexible polishing chain (6-2) and ladder type flexible polishing chain (6-3) form;

[0010] (5) Control system control mechanical arm (1-1) drive connecting disc (2-1) rotary motion, three flexible polishing chains (1-2) under the drive of connecting disc (2-1) rotate, polishing belt (3-7) and variable curvature tube inner surface produce relative motion, realize high quality and high efficiency polishing;

[0011] (6) After polishing, the upper end electromagnetic iron (4-2) and the lower end electromagnetic iron (4-3) are controlled to be in the third current mode (8-3), at this time, the upper end electromagnetic iron (4-2) and the lower end electromagnetic iron (4-3) have different charges, and the slide groove (4-4) drives the check valve (4-7) to move upwards and engage with the upper end rack gear (4-5), the position of the rubber tube movable support (3-3) is detected by the position sensor (4-9), the left end electromagnetic iron (4-8) and the right end electromagnetic iron (4-10) are controlled to be in the second current mode (8-2), at this time, the left end electromagnetic iron (4-8) and the right end electromagnetic iron (4-10) have the same charge, and the rubber tube support bone joint (3-12) moves to the upper side of the initial position, the upper end electromagnetic iron (4-2) and the lower end electromagnetic iron (4-3) are controlled to be in the fourth current mode (8-4), at this time, the upper end electromagnetic iron (4-2) and the lower end electromagnetic iron (4-3) have the same charge, and the slide groove (4-4) drives the check valve (4-7) to move downwards and engage with the lower end rack gear (4-11), the left end electromagnetic iron (4-8) and the right end electromagnetic iron (4-10) are controlled to be in the first current mode (8-1), at this time, the left end electromagnetic iron (4-8) and the right end electromagnetic iron (4-10) have different charges, and the rubber tube movable support (3-3) is fixed at the initial position, the three flexible polishing chains (1-2) return to the initial state, and the polishing work is completed.

[0012] The beneficial effects of the present application are:

[0013] 1. A variable curvature pipe inner surface polishing device, the concave bending flexible air pressure rubber pipe bends downward when inflated, the convex bending flexible air pressure rubber pipe bends upward when inflated, the concave bending flexible air pressure rubber pipe and the convex bending flexible air pressure rubber pipe are arranged in pairs and in parallel on three flexible polishing chains, avoiding the single bending direction of the three flexible polishing chains and ensuring the multidirectional composite bending of the three flexible polishing chains. 2. A variable curvature pipe inner surface polishing device, the distance between the rubber pipe movable support and the sliding groove can be adjusted through the sliding groove hinge, the position sensor is installed on the rubber pipe support bone joint to feedback the distance between the rubber pipe movable support and the position sensor in real time, and the size of the air pressure in the air pressure passage is adjusted to change the fulcrum position and the bending degree of the convex bending flexible air pressure rubber pipe, form U-shaped flexible polishing chain, sinusoidal flexible polishing chain and stepped flexible polishing chain, and realize the constant force close contact to the complex variable curvature pipe inner surface. 3. A variable curvature pipe inner surface polishing device, the three flexible polishing chains are uniformly arranged on the connecting disc, so that the pressure of the three flexible polishing chains on the workpiece inner surface is uniformly distributed, the relative friction degree of the three polishing belts and the variable curvature pipe inner surface is consistent, and the uniform polishing of the variable curvature pipe inner surface is realized. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is the overall structure schematic diagram of a variable curvature pipe inner surface polishing device and method.

[0015] Figure 2 is the polishing device structure schematic diagram of a variable curvature pipe inner surface polishing device and method.

[0016] Figure 3 is the flexible polishing chain structure schematic diagram of a variable curvature pipe inner surface polishing device and method.

[0017] Figure 4 is the single bone joint structure schematic diagram of a variable curvature pipe inner surface polishing device and method.

[0018] Figure 5 is the check valve structure schematic diagram of a variable curvature pipe inner surface polishing device and method.

[0019] Figure 6 is the part flexible polishing chain working state schematic diagram of a variable curvature pipe inner surface polishing device and method.

[0020] Figure 7 is the flexible air pressure rubber pipe bending state schematic diagram of a variable curvature pipe inner surface polishing device and method.

[0021] Figure 8Figure 1 is a schematic diagram of an electromagnet current pattern for a variable curvature tube inner surface polishing apparatus and method of the present invention. DETAILED DESCRIPTION

[0022] DETAILED DESCRIPTION Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5The device comprises a mechanical arm (1-1), three flexible polishing chains (1-2), the end of the mechanical arm (1-1) is connected with the connecting disc (2-1) through screw connection, the three flexible polishing chains (1-2) are connected on the connecting disc (2-1) through hinge (2-2), each polishing chain of the three flexible polishing chains (1-2) is composed of 10 joint units (2-3), the joint unit (2-3) comprises four-position four-way electromagnetic valve (3-1), axial rolling bearing (3-2), rubber tube movable support (3-3), concave bending flexible pneumatic rubber tube (3-4), convex bending flexible pneumatic rubber tube (3-5), pressure sensor (3-6), polishing belt (3-7), rubber tube connecting hinge fixing plate (3-8), rubber tube connecting hinge (3-9), electromagnetic valve fixing base (3-10), joint side hinge (3-11), rubber tube supporting joint (3-12), interosseous hinge (3-13), rubber tube fixing support (3-14), distance control device, the rubber tube supporting joint (3-12) is connected through the interosseous hinge (3-13), one side of the rubber tube connecting hinge fixing plate (3-8) is fixed with the four-position four-way electromagnetic valve (3-1) through the electromagnetic valve fixing base (3-10), the other side is fixed on the rubber tube connecting hinge (3-9), one side of the concave bending flexible pneumatic rubber tube (3-4) and the convex bending flexible pneumatic rubber tube (3-5) is fixed on the rubber tube connecting hinge fixing plate (3-8) through screw connection, the other side is connected with the four-position four-way electromagnetic valve (3-1) through the pneumatic hose, the joint units (2-3) are sequentially connected through the rubber tube connecting hinge (3-9), the pressure sensor (3-6) is attached to the outer ring surface of the rubber tube movable support (3-3) and the outer ring surface of the rubber tube fixing support (3-14), the polishing belt (3-7) is attached to the outer side of the axial rolling bearing (3-2), the rubber tube fixing support (3-14) and the rubber tube supporting joint (3-12) are connected through the spherical hinge, the distance control device comprises support spring (4-1), longitudinal upper end electromagnet (4-2), longitudinal lower end electromagnet (4-3), sliding groove (4-4), upper end gear rack (4-5), sliding groove hinge (4-6), backstop (4-7), transverse left end electromagnet (4-8), position sensor (4-9), transverse right end electromagnet (4-10), lower end gear rack (4-11), the rubber tube movable support (3-3) is provided with the longitudinal upper end electromagnet (4-2), the rubber tube supporting joint (3-12) is fixed with the upper end gear rack (4-5) and the lower end gear rack (4-11) through screw connection, and one side is provided with the position sensor (4-9) and the transverse right end electromagnet (4-10), one end of the support spring (4-1) is fixed on the rubber tube movable support (3-3) through screw connection, the other end is fixed on the rubber tube supporting joint (3-12).The chute (4-4) is provided with a longitudinal lower end electromagnet (4-3) and a transverse left end electromagnet (4-8), the chute (4-4) is connected with the rubber tube movable support (3-3) through a chute hinge (4-6), the check stopper (4-7) comprises a check stopper outer ring (5-1), a check stopper inner ring (5-2), a check stopper spring (5-3) and a check stopper hinge (5-4), the check stopper inner ring (5-2) is fixedly connected with the check stopper hinge (5-4) through a connecting pin, one end of the check stopper spring (5-3) is fixed on the check stopper hinge (5-4) through screw connection, and the other end is fixed on the check stopper inner ring (5-2), and the check stopper inner ring (5-2) is in interference fit with the rubber tube movable support (3-3).

[0023] Specific embodiment two: combined Figure 7 It is explained that the concave curved flexible air pressure rubber tube (3-4) will be concave curved downward (7-1) when inflated, the convex curved flexible air pressure rubber tube (3-5) will be convex curved upward (7-2) when inflated, and the rest is the same as in specific embodiment one.

[0024] Specific embodiment three: combined Figure 3 , Figure 4 It is explained that the distance between the rubber tube movable support (3-3) and the chute (4-4) can be adjusted through the chute hinge (4-6), the position sensor (4-9) is arranged on the rubber tube support bone (3-12) to feedback the distance between the rubber tube movable support (3-3) and the position sensor (4-9) in real time, and the rest is the same as in specific embodiment one or two.

[0025] Specific embodiment four: combined Figure 3 , Figure 6 It is explained that the concave curved flexible air pressure rubber tube (3-4) and the convex curved flexible air pressure rubber tube (3-5) are arranged in pairs and in parallel on each flexible polishing chain (1-2), by changing the position of the bending fulcrum and the bending degree of the convex curved flexible air pressure rubber tube (3-5), a U-shaped flexible polishing chain (6-1), a sinusoidal flexible polishing chain (6-2) and a stepped flexible polishing chain (6-3) can be formed, so that the pressure of the polishing belt (3-7) in contact with the inner surface of the variable curvature pipe is constant, and the rest is the same as in specific embodiment one, two or three.

[0026] Specific embodiment five: combined Figure 3 , Figure 4 It is explained that after polishing, the three flexible polishing chains (1-2) are arranged uniformly on the connecting disc (2-1) to realize uniform polishing of the inner surface of the variable curvature pipe, and the rest is the same as in specific embodiment one, two, three or four.

[0027] Specific implementation six: combined Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 This embodiment uses the device described in any one of specific implementations one, two, three, four or five to perform the polishing step as follows:

[0028] (1) Fix the three flexible polishing chains (1-2) on the mechanical arm (1-1) through the connecting disc (2-1), and drive the mechanical arm (1-1) to drive the three flexible polishing chains (1-2) into the variable curvature pipe;

[0029] (2) Control the air pressure driving device, and pass compressed gas into the convex curved flexible air pressure rubber pipe (3-5) on the ten bone joint units (2-3) through the four-position four-way electromagnetic valve (3-1) to drive the three flexible polishing chains (1-2) to realize preliminary bending and fitting on the inner surface of the variable curvature pipe;

[0030] (3) The pressure sensor (3-6) feeds back the pressure of the three flexible polishing chains (1-2) fitted on the inner surface of the variable curvature pipe to the control system. If the pressure displayed by the pressure sensor (3-6) is higher than the target value, control the transverse left end electromagnet (4-8) and the transverse right end electromagnet (4-10) to pass current mode two (8-2). At this time, the right end of the transverse left end electromagnet (4-8) and the left end of the transverse right end electromagnet (4-10) have the same charge, generating repulsive force to drive the rubber pipe movable support (3-3) to move axially. If the pressure displayed by the pressure sensor (3-6) is lower than the target value, the control system drives the four-position four-way electromagnetic valve (3-1) to change the air pressure passage, drives the concave curved flexible air pressure rubber pipe (3-4) to bend, controls the longitudinal upper end electromagnet (4-2) and the longitudinal lower end electromagnet (4-3) to pass current mode three (8-3). At this time, the lower end of the longitudinal upper end electromagnet (4-2) and the upper end of the longitudinal lower end electromagnet (4-3) have different charges, generating attractive force to drive the rubber pipe movable support (3-3) to move axially in the opposite direction. At the same time, the size of the air pressure in the air pressure passage is adjusted to change the fulcrum position and bending degree of the convex curved flexible air pressure rubber pipe (3-5), so as to form a U-shaped flexible polishing chain (6-1), a sinusoidal flexible polishing chain (6-2) and a stepped flexible polishing chain (6-3), and finally make the polishing belt (3-7) contact the inner surface of the variable curvature pipe. The pressure of the contact area is constant, realizing constant force and efficient polishing processing of the inner surface of the complex variable curvature pipe;

[0031] (4) Control the left end electromagnetic (4-8) and the right end electromagnetic (4-10) into current mode one (8-1), at this time the left end electromagnetic (4-8) right end and the right end electromagnetic (4-10) left end with heterotypic electric charge, produce attractive force, make the chute (4-4) drive rubber tube movable support (3-3) move to the direction of position sensor (4-9), namely positive right movement, the position sensor (4-9) detects the rubber tube movable support (3-3) moves to the target position, control the left end electromagnetic (4-8) and the right end electromagnetic (4-10) into current mode two (8-2), at this time the left end electromagnetic (4-8) right end and the right end electromagnetic (4-10) left end with the same electric charge, produce repulsive force, at the same time support spring (4-1) generates reverse left return force to the rubber tube movable support (3-3), check valve (4-7) limits the rubber tube movable support (3-3) reverse left return, makes the rubber tube movable support (3-3) fixed in the target position, guarantees the stability of the formed U-shaped flexible polishing chain (6-1), sinusoidal flexible polishing chain (6-2) and ladder type flexible polishing chain (6-3) form;

[0032] (5) Control system control mechanical arm (1-1) drive connecting disc (2-1) rotary motion, three flexible polishing chains (1-2) under the drive of connecting disc (2-1) rotate, polishing belt (3-7) and variable curvature tube inner surface produce relative motion, realize high quality and high efficiency polishing;

[0033] (6) After polishing, control the upper end of the longitudinal electromagnet (4-2) and the lower end of the longitudinal electromagnet (4-3) into the current mode three (8-3), at this time the upper end of the longitudinal electromagnet (4-2) and the lower end of the longitudinal electromagnet (4-3) have different charges, produce attractive force, attract the chute (4-4) to drive the check valve (4-7) to move up and engage to the upper end of the rack (4-5), through the position sensor (4-9) to detect the position of the rubber tube movable support (3-3), control the left end of the horizontal electromagnet (4-8) and the right end of the horizontal electromagnet (4-10) into the current mode two (8-2), at this time the right end of the horizontal electromagnet (4-8) and the left end of the horizontal electromagnet (4-10) have the same charge, produce repulsive force, make the rubber tube support bone joint (3-12) move to the initial position above, control the upper end of the longitudinal electromagnet (4-2) and the lower end of the longitudinal electromagnet (4-3) into the current mode four (8-4), at this time the upper end of the longitudinal electromagnet (4-2) and the lower end of the longitudinal electromagnet (4-3) have the same charge, produce repulsive force, push the chute (4-4) to drive the check valve (4-7) to move down and engage to the lower end of the rack (4-11), control the left end of the horizontal electromagnet (4-8) and the right end of the horizontal electromagnet (4-10) into the current mode one (8-1), at this time the right end of the horizontal electromagnet (4-8) and the left end of the horizontal electromagnet (4-10) have different charges, produce attractive force, make the rubber tube movable support (3-3) fixed in the initial position, three flexible polishing chain (1-2) restore to the initial state, complete the polishing work.

Claims

1. A method of polishing with a variable curvature tube inner surface polishing apparatus, characterized by, The device comprises a mechanical arm (1-1), three flexible polishing chains (1-2), the mechanical arm (1-1) is connected with a connecting disc (2-1) through screw connection, the three flexible polishing chains (1-2) are connected on the connecting disc (2-1) through a hinge (2-2), each polishing chain of the three flexible polishing chains (1-2) is composed of 10 joint units (2-3), the joint unit (2-3) comprises a four-position four-way electromagnetic valve (3-1), an axial rolling bearing (3-2), a rubber tube movable support (3-3), a concave curved flexible pneumatic rubber tube (3-4), a convex curved flexible pneumatic rubber tube (3-5), a pressure sensor (3-6), a polishing belt (3-7), a rubber tube connecting hinge fixing plate (3-8), a rubber tube connecting hinge (3-9), an electromagnetic valve fixing base (3-10), a joint side hinge (3-11), a rubber tube supporting joint (3-12), an interosseous hinge (3-13), a rubber tube fixing support (3-14), a distance control device, the rubber tube supporting joint (3-12) is connected through the interosseous hinge (3-13), one side of the rubber tube connecting hinge fixing plate (3-8) is fixed with the four-position four-way electromagnetic valve (3-1) through the electromagnetic valve fixing base (3-10), and the other side is fixed on the rubber tube connecting hinge (3-9), one side of the concave curved flexible pneumatic rubber tube (3-4) and the convex curved flexible pneumatic rubber tube (3-5) is fixed on the rubber tube connecting hinge fixing plate (3-8) through screw connection, and the other side is connected with the four-position four-way electromagnetic valve (3-1) through a pneumatic hose, the joint units (2-3) are sequentially connected through the rubber tube connecting hinge (3-9), the pressure sensor (3-6) is attached to the outer ring surface of the rubber tube movable support (3-3) and the outer ring surface of the rubber tube fixing support (3-14), the polishing belt (3-7) is attached to the outer side of the axial rolling bearing (3-2), the rubber tube fixing support (3-14) and the rubber tube supporting joint (3-12) are connected through a spherical hinge, and the distance control device comprises a support spring (4-1), a longitudinal upper end electromagnet (4-2), a longitudinal lower end electromagnet (4-3), a sliding groove (4-4), an upper end gear rack (4-5), a sliding groove hinge (4-6), a backstop (4-7), a transverse left end electromagnet (4-8), a position sensor (4-9), a transverse right end electromagnet (4-10), and a lower end gear rack (4-11), the rubber tube movable support (3-3) is provided with the longitudinal upper end electromagnet (4-2), the rubber tube supporting joint (3-12) is fixed with the upper end gear rack (4-5) and the lower end gear rack (4-11) through screw connection, and is provided with the position sensor (4-9) and the transverse right end electromagnet (4-10) on one side, one end of the support spring (4-1) is fixed on the rubber tube movable support (3-3) through screw connection, and the other end is fixed on the rubber tube supporting joint (3-12).The chute (4-4) is provided with a longitudinal lower end electromagnet (4-3) and a transverse left end electromagnet (4-8), the chute (4-4) is connected with the rubber tube movable support (3-3) through a chute hinge (4-6), the check (4-7) comprises a check outer ring (5-1), a check inner ring (5-2), a check spring (5-3) and a check hinge (5-4), the check inner ring (5-2) is fixedly connected with the check hinge (5-4) through a connecting pin, one end of the check spring (5-3) is fixed on the check hinge (5-4) through screw connection, and the other end is fixed on the check inner ring (5-2), and the check inner ring (5-2) is in interference fit with the rubber tube movable support (3-3); the polishing method mainly comprises the following steps: (1) Three flexible polishing chains (1-2) are fixed on the mechanical arm (1-1) through the connecting plate (2-1), and the mechanical arm (1-1) is driven to drive the three flexible polishing chains (1-2) into the variable curvature pipe; (2) The air pressure driving device is controlled, the compressed gas is introduced into the convex curved flexible air pressure rubber pipe (3-5) on the 10 bone joint units (2-3) through the four-position four-way electromagnetic valve (3-1), and the three flexible polishing chains (1-2) are driven to realize preliminary bending and fitting on the inner surface of the variable curvature pipe; (3) The pressure sensor (3-6) feeds back the pressure of the three flexible polishing chains (1-2) fitted on the inner surface of the variable curvature pipe to the control system, if the pressure shown by the pressure sensor (3-6) is higher than the target value, the control system drives the horizontal left end electromagnet (4-8) and the horizontal right end electromagnet (4-10) to input current mode two (8-2), at this time, the right end of the horizontal left end electromagnet (4-8) and the left end of the horizontal right end electromagnet (4-10) have the same charge, repulsion is generated, the rubber pipe movable support (3-3) is driven to move axially, if the pressure shown by the pressure sensor (3-6) is lower than the target value, the control system drives the four-position four-way electromagnetic valve (3-1) to change the air pressure passage, drives the concave curved flexible air pressure rubber pipe (3-4) to bend, controls the longitudinal upper end electromagnet (4-2) and the longitudinal lower end electromagnet (4-3) to input current mode three (8-3), at this time, the lower end of the longitudinal upper end electromagnet (4-2) and the upper end of the longitudinal lower end electromagnet (4-3) have different charges, attraction is generated, the rubber pipe movable support (3-3) is driven to move reversely, at the same time, the size of the air pressure in the air pressure passage is regulated, the bending fulcrum position and the bending degree of the convex curved flexible air pressure rubber pipe (3-5) can be changed, the U-shaped flexible polishing chain (6-1), the sinusoidal flexible polishing chain (6-2) and the stepped flexible polishing chain (6-3) can be formed, finally, the pressure of the polishing belt (3-7) and the contact area of the inner surface of the variable curvature pipe is constant, the constant force efficient polishing machining of the inner surface of the complex variable curvature pipe is realized. (4) Control the left end electromagnetic (4-8) and the right end electromagnetic (4-10) into the current mode one (8-1), at this time the left end electromagnetic (4-8) right end and the right end electromagnetic (4-10) left end with heterotypic charge, produce attractive force, make the chute (4-4) drive rubber tube movable support (3-3) move to the direction of position sensor (4-9), namely positive right movement, the position sensor (4-9) detects the rubber tube movable support (3-3) moves to the target position, control the left end electromagnetic (4-8) and the right end electromagnetic (4-10) into the current mode two (8-2), at this time the left end electromagnetic (4-8) right end and the right end electromagnetic (4-10) left end with the same charge, produce repulsive force, at the same time support spring (4-1) generates the reverse left return force to the rubber tube movable support (3-3), check valve (4-7) restricts the rubber tube movable support (3-3) reverse left return, makes the rubber tube movable support (3-3) fixed in the target position, guarantees the stability of the formed U type flexible polishing chain (6-1), sinusoidal flexible polishing chain (6-2) and ladder type flexible polishing chain (6-3) form; (5) Control system control mechanical arm (1-1) drive connecting disc (2-1) rotary motion, three flexible polishing chain (1-2) under the drive of connecting disc (2-1) rotate, polishing belt (3-7) and variable curvature tube inner surface produce relative motion, realize high quality and high efficiency polishing; (6) After polishing, the upper longitudinal electromagnet (4-2) and the lower longitudinal electromagnet (4-3) are controlled to pass through mode three (8-3) of current, at this time, the upper end of the upper longitudinal electromagnet (4-2) and the lower end of the lower longitudinal electromagnet (4-3) have different charges, generating attractive force, attracting the chute (4-4) to drive the check valve (4-7) to move upwards and engage with the upper end gear rack (4-5), through the position sensor (4-9) to detect the position of the rubber tube movable support (3-3), the left horizontal electromagnet (4-8) and the right horizontal electromagnet (4-10) are controlled to pass through mode two (8-2) of current, at this time, the right end of the left horizontal electromagnet (4-8) and the left end of the right horizontal electromagnet (4-10) have the same charge, generating repulsive force, making the rubber tube support bone segment (3-12) move to the position above the initial position, the upper longitudinal electromagnet (4-2) and the lower longitudinal electromagnet (4-3) are controlled to pass through mode four (8-4) of current, at this time, the upper end of the upper longitudinal electromagnet (4-2) and the lower end of the lower longitudinal electromagnet (4-3) have the same charge, generating repulsive force, pushing the chute (4-4) to drive the check valve (4-7) to move downwards and engage with the lower end gear rack (4-11), the left horizontal electromagnet (4-8) and the right horizontal electromagnet (4-10) are controlled to pass through mode one (8-1) of current, at this time, the right end of the left horizontal electromagnet (4-8) and the left end of the right horizontal electromagnet (4-10) have different charges, generating attractive force, making the rubber tube movable support (3-3) fixed at the initial position, the three flexible polishing chains (1-2) return to the initial state, completing the polishing work.

2. A method of polishing with a variable curvature tube inner surface polishing apparatus according to claim 1, wherein The concave curved flexible pneumatic rubber tube (3-4) is concave curved downwards (7-1) when inflated, and the convex curved flexible pneumatic rubber tube (3-5) is convex curved upwards (7-2) when inflated.

3. A method of polishing with a variable curvature tube inner surface polishing apparatus as defined in claim 1, wherein The distance between the rubber tube movable support (3-3) and the chute (4-4) can be adjusted by the chute hinge (4-6), and the rubber tube support bone segment (3-12) is provided with a position sensor (4-9) for real-time feedback of the distance between the rubber tube movable support (3-3) and the position sensor (4-9).

4. A method of polishing with a variable curvature tube inner surface polishing apparatus as defined in claim 1, wherein The concave curved flexible pneumatic rubber tube (3-4) and the convex curved flexible pneumatic rubber tube (3-5) are arranged in pairs and in parallel on the three flexible polishing chains (1-2).

5. A method of polishing using a variable curvature tube inner surface polishing apparatus according to claim 1, wherein The three flexible polishing chains (1-2) are arranged uniformly in a circle on the connecting disc (2-1).

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