CN112975765A

CN112975765A - Deep hole V type supersound shot-blasting machine

Info

Publication number: CN112975765A
Application number: CN202110158615.7A
Authority: CN
Inventors: 白富实; 杨坤德
Original assignee: Northwestern Polytechnical University
Current assignee: Northwestern Polytechnical University
Priority date: 2021-02-05
Filing date: 2021-02-05
Publication date: 2021-06-18
Anticipated expiration: 2041-02-05
Also published as: CN112975765B

Abstract

The deep hole V-shaped ultrasonic shot blasting device is provided with a first transducer and a second transducer, the main body parts of the first transducer and the second transducer are connected through a transducer connecting piece, the included angle of the axes of the first transducer and the second transducer is 90 degrees, the first transducer and the second transducer are identical in structure, amplitude-changing rods are arranged at the front parts of the first transducer and the second transducer, the end parts of the amplitude-changing rods are connected through a connecting block, an elongated tool head is connected onto the connecting block, the axis of the elongated tool head is orthogonal to the axes of the first transducer and the second transducer, a shot blasting part is arranged at the front end of the elongated tool head, the shot blasting part is provided with an annular groove, and the annular groove and the inner wall of a deep hole form a shot blasting cavity. The ultrasonic shot peening strengthening method can realize uniform shot peening strengthening of the inner wall of the deep hole in the whole circumferential direction, effectively improve the efficiency of ultrasonic shot peening strengthening, has obvious effect, and can be widely applied to surface strengthening of various metal deep holes.

Description

Deep hole V type supersound shot-blasting machine

Technical Field

The invention relates to the field of shot peening strengthening of metal surfaces, in particular to a deep-hole V-shaped ultrasonic shot blasting device.

Background

With the needs of economic development and national defense development in China, a plurality of metal parts are required to be used under the conditions of high temperature, high pressure, high speed and the like, the alternating stress borne by the metal parts is higher and higher, the problem of fatigue fracture is more and more prominent, and the connecting hole in the equipment member is often a key part for fatigue failure. The research finds that a great number of potential cracks on the hole wall are the main cause of the fatigue failure of the component. In addition to the connection holes, more and more deep holes are present in some equipment in the fields of aviation, aerospace and navigation, such as axial oil holes, cylinder bores, hydraulic valve bores and hollow spindle bores of marine diesel engines, in order to achieve specific mechanical functions. Deep holes have hitherto accounted for over 40% in mechanical manufacture. Due to process limitation, the cutting performance of the machined materials of some holes is poor, and meanwhile, the deep hole machining has the characteristics of self particularity, invisibility, difficult chip removal, high oil temperature and the like.

Therefore, the quality of the surface of the hole is difficult to achieve the ideal effect, so that the later surface strengthening treatment is particularly important. Due to the limitation of geometric dimension, the traditional sand blasting and shot blasting process, the laser shot blasting process and the cavitation shot blasting process can not carry out surface strengthening on the deep hole. However, the ultrasonic peening process has many advantages: such as deep residual compressive stress layer, less dust and noise pollution, simple equipment, low power consumption, controllable process parameters, nanocrystalline grain formed on the surface, and the like. Ultrasonic shot blasting is widely applied to plane or large-curvature surface parts, such as skin, crankshafts and the like, but shot blasting treatment on deep holes is not carried out, so that the application of the ultrasonic shot blasting on engineering is severely limited.

Disclosure of Invention

Based on the technical problems, the invention provides the ultrasonic shot blasting device based on the V-shaped transducer and the deep hole surface strengthening method, the ultrasonic shot blasting device can realize uniform shot blasting strengthening on the inner wall of the deep hole in the whole circumferential direction, effectively improves the efficiency of ultrasonic shot blasting strengthening, has obvious effect, and can be widely applied to surface strengthening of various metal deep holes.

The invention adopts the specific technical scheme that: the utility model provides a deep hole V type supersound shot-blasting machine, has first transducer and second transducer, the main part of first transducer and second transducer passes through the transducer connecting piece and connects, the axis contained angle of first transducer and second transducer is 90 degrees, first transducer and second transducer structure are the same, first transducer and second transducer front portion have become width of cloth pole, the tip of a width of cloth pole passes through the connecting block to be connected, be connected with long and thin instrument head on the connecting block, the axis of long and thin instrument head with the axis quadrature of first transducer and second transducer, the front end of long and thin instrument head is provided with peening portion, peening portion has the annular, the annular forms the peening chamber with the downthehole wall of annular and deep hole.

Furthermore, the first transducer applies a first simple harmonic voltage signal, the second transducer applies a second simple harmonic voltage signal, the phase difference between the first simple harmonic voltage signal and the second simple harmonic voltage signal is pi/2, the elongated tool head generates an n (n is more than or equal to 0, and n is an integer) order bending vibration mode, and the elongated tool head performs micro amplitude orbiting around the axis after bending vibration is orthogonal.

Further, the working frequency of the first transducer and the second transducer is more than or equal to 20 kHz.

Further, the elongated tool head has a shank body, the peen portion is provided at an end of the shank body, the ring groove of the peen portion is composed of an upper flange, a shank head section, and a lower flange, and a diameter of the shank head section is smaller than diameters of the upper flange and the lower flange.

Further, the peen part is detachably connected with the rod body.

Further, the two ends of the rod body are provided with threaded portions, the connecting blocks are rectangular blocks, and threaded holes are formed in three adjacent surfaces of each rectangular block respectively.

Further, gaps are reserved between the upper flange and the lower flange of the shot blasting part and the inner wall of the hole.

Further, the transducer connector comprises a horizontal section and inclined sections arranged on two sides of the horizontal section, and the inclined sections are used for mounting the first transducer and the second transducer.

A deep hole surface strengthening method uses the deep hole V-shaped ultrasonic shot blasting device and comprises the following steps:

s, selecting shot blasting tool heads with different sizes according to different hole diameters and hole depths;

s, placing shot blasting pellets in a ring groove of a shot blasting part;

s, inserting the slender tool head into the hole and staying at the bottom of the hole;

s, respectively applying voltage signals with a phase difference of pi/simple harmonic to the first transducer and the second transducer;

and S, controlling the slender tool head to reciprocate along the axial direction of the hole to finish the surface strengthening of the inner wall of the hole.

Further, the shot-blasting pellets are contained in an amount of about 10% of the total volume between the peen part and the inner wall of the hole.

Compared with the prior art, the invention has the technical effects that: the invention forms a V-shaped transducer by two Langewen transducers, the two transducers are connected by a connecting block, and simultaneously, a piezoelectric signal with the phase difference of pi/2 acts on the two transducers, thereby generating multi-stage bending vibration on a tool head, the end part of the tool head is provided with a shot blasting part for receiving shot blasting pills, the shot blasting part extends into a hole to form a shot blasting cavity with the hole wall, and the shot blasting pills in the shot blasting cavity are impacted by the tool head to generate ultrasonic frequency vibration, thereby realizing shot blasting strengthening on the hole wall. Meanwhile, different shot blasting parts can be replaced according to different holes, the replacement is convenient, and the application range of the equipment is expanded.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention or in the description of the prior art will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic view of the overall structure of the deep-hole V-shaped ultrasonic shot-blasting machine of the present invention;

FIG. 2 is a block diagram of a transducer of the present invention;

FIG. 3 is a block diagram of an elongated tool head of the present invention;

FIG. 4 is a schematic view of a peen chamber of the present invention;

FIG. 5 is a diagram of a connection block of the present invention;

FIG. 6 is a diagram of a transducer connector of the present invention;

FIG. 7 is a diagram of the transducer mounting plate of the present invention.

Description of reference numerals: 10. a first transducer; 101. a stud; 102. a pre-tightening force bolt; 103. a rear end cap; 104. a piezoelectric unit; 105. an amplitude transformer; 106. a transducer mounting plate; 20. a second transducer; 30. an elongated tool head; 301. a rod body; 302. a shot blasting section; 303. a ring groove; 304. an upper flange; 305. a rod head section; 306. a lower flange; 40. a transducer connector; 401. a fastener; 402. an inclined section; 403. a horizontal segment; 50. connecting blocks; 60. an inner wall of the bore; 70. shot blasting and pelleting; 80. and (4) a shot blasting cavity.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments.

The deep-hole V-shaped ultrasonic shot blasting device is used for strengthening the inner surface of a metal deep hole, can realize the strengthening effect on the inner surface of the deep hole, can be used for a blind hole, and expands the engineering application field and range of the ultrasonic shot blasting device. Specifically, as shown in fig. 1-7, there is a first transducer 10 and a second transducer 20, the main body parts of the first transducer 10 and the second transducer 20 are connected by a transducer connector 40, the included angle between the axes of the first transducer 10 and the second transducer 20 is 90 degrees, and the two transducers form a V-shaped transducer as a whole. The structure of the first transducer 10 is the same as that of the second transducer 20, the front parts of the first transducer 10 and the second transducer 20 are provided with the amplitude transformer 105, the end parts of the two amplitude transformers 105 are connected through the connecting block 50, the connecting block 50 is connected with the slender tool head 30, the axis of the slender tool head 30 is orthogonal to the axis of the first transducer 10 and the axis of the second transducer 20, the front end of the slender tool head 30 is provided with a shot-peening part 302, the shot-peening part is provided with an annular groove 303, the annular groove 303 and the inner hole wall 60 of the deep hole form a shot-peening cavity 80, and the shot-peening 70 is accommodated in the shot-peening cavity 80.

Specifically, the first transducer 10 and the second transducer 20 are langevin transducers, and each transducer includes a rear end cap 103, a piezoelectric element 104, and a horn 105. The pretightening bolt 102 fixes the rear end cover 103 and the piezoelectric unit 104 at the rear end of the amplitude transformer 105 through the stud 101.

As shown in fig. 2, the piezoelectric unit 104 is composed of four piezoelectric elements with a central through hole and polarized along the thickness direction, and the polarization directions of any two adjacent piezoelectric units are opposite, specifically, a piezoelectric ceramic group composed of circular piezoelectric ceramic sheets, as shown in fig. 2. A part of a variable amplitude rod 105 of the Langewen transducer is arranged to be of a cylindrical beam structure and is used for being connected with the piezoelectric unit 104, the other end of the variable amplitude rod is arranged to be of a variable cross-section beam structure and is used for being connected with the connecting block 50, and the connecting block 50 achieves installation and fixation of the whole Langewen transducer.

Further, the first transducer 10 applies a first simple harmonic voltage signal, the second transducer 20 applies a second simple harmonic voltage signal, the phase difference between the first simple harmonic voltage signal and the second simple harmonic voltage signal is pi/2, the head of the elongated tool head 30 generates an n (n is not less than 0, n is an integer) order bending vibration mode, and the elongated tool head 30 performs micro amplitude winding around the axis after bending vibration is orthogonal.

The piezoelectric ceramic group is connected with an ultrasonic power supply, the ultrasonic power supply respectively generates two simple harmonic voltage signals with the phase difference of pi/2, and the electric signals are converted into mechanical vibration and respectively transmitted to the amplitude transformer 105. The amplitude transformer 10 amplifies the amplitude of the vibration generated by the piezo ceramic stack and transmits the amplified amplitude to the connector block 50, and the connector block 50 is connected to the other end of the elongate tool tip 30.

Specifically, the piezoelectric element 104 of the first transducer 10 applies a first simple harmonic voltage signal to excite a first-order longitudinal vibration of the first transducer 10 and induce a first-order bending vibration of the second transducer 20; similarly, applying the second simple harmonic voltage signal to the piezoelectric element 104 of the second transducer 20 excites the first order longitudinal vibration of the second transducer 20 and induces the first order flexural vibration of the first transducer 10. As shown in FIG. 3, the tool head 30 generates multi-step bending vibration and bending vibration coupling orthogonal to the vibration in two directions, so that a section connected with the shot-peening chamber 80 makes a micro-amplitude circular motion around an axis, and the micro-amplitude circular motion of the shot-peening part 302 makes shot-peening pellets 70 in the shot-peening chamber 80 make a random linear motion to impact the inner wall surface of the deep hole at high speed, thereby realizing shot-peening on the wall of the deep hole.

Further, the working frequency of the first transducer 10 and the second transducer 20 is greater than or equal to 20kHz, and the ultrasonic frequency has a great influence on the mechanical properties of the inner wall 60 of the hole after ultrasonic peening, and in order to increase the strengthening effect, the ultrasonic frequency should be selected to be about 20kHz and not less than 20 kHz.

Further, the elongated tool bit 30 has a shank body 301, the peen portion 302 is disposed at an end of the shank body 301, the annular groove 303 of the peen portion 302 is formed by an upper flange 304, a tip section 305 and a lower flange 306, the diameter of the tip section 305 is smaller than the diameters of the upper flange 304 and the lower flange 306, and preferably, the diameter of the tip section 305 is 1/2 to 1/3 of the diameters of the upper flange 304 and the lower flange 306, so that a sufficient number of shot pellets 70 can be contained in the peen portion 302.

Further, the peen part 302 is detachably connected with the rod body 301, and the center of the rod body 301 and the peen part 302 of the slender tool head 30 can be connected through a double-end stud to form an ultrasonic assembly, so that only the peen part 302 can be replaced to strengthen deep holes with different inner diameters. Specifically, a threaded hole is formed in an upper flange 304 of the shot-peening portion 302, a thread is formed on the outer circumference of one end of the rod body 301, and the shot-peening portion 302 and the rod body 301 are connected by the thread. The other end of the rod body 301 is also threaded, as shown in fig. 5, the connecting block 50 is a rectangular block, three adjacent surfaces of the rectangular block are respectively provided with a threaded hole, and the connecting block 50 and the rod body 301 are connected through threads. Two holes arranged on the side surface are blind holes and are used for connecting two amplitude transformer 105, and external threads are formed at the tail end of the amplitude transformer 105; a hole arranged in the center is used for connecting the rod body 301, and the hole is a blind hole or a through hole; when different holes are machined, peen portions 302 of different sizes may be selected to be mounted on the rod body 301. Specifically, the peen 302 may be designed with different diameters for the upper flange 304 and the lower flange 306 and different diameters and lengths for the club head section 305 depending on the hole.

Specifically, the peen part 302 and the inner wall 60 of the hole form the peen chamber 80, the peen part 302 and the inner wall 60 of the hole form a semi-closed space, a certain gap exists between the upper flange 304 and the lower flange 306 of the peen part 302 and the inner wall 60 of the hole, namely the diameter of the upper flange 304 and the diameter of the lower flange 306 are smaller than the inner diameter of the hole, the size of the gap is far smaller than the diameter of the peen pellet 70, so that the peen part 302 can make micro-amplitude movement, and the peen pellet 70 cannot leak out. The shot-blasting portion 302 makes a micro-amplitude circular motion around the axis in the deep hole to generate a tangential amplitude and a longitudinal amplitude to stimulate the shot to move at a high speed in the shot-blasting cavity 80, as shown in fig. 4, the ultrasonic vibration generated by the shot-blasting portion 302 impacts the shot-blasting shot 70 to move, the tangential speed enables the shot-blasting shot 70 to make a random motion around the radiation surface in the shot-blasting cavity 80, impact points are distributed more uniformly on the whole, and the coverage rate of the shot-blasting shot 70 is improved. The radial high-speed vibration enables the pills to move at high speed to impact the inner wall 60 of the hole, plastic deformation is generated, and a nano layer is formed, so that the ultrasonic shot blasting effect is obviously improved.

Further, as shown in fig. 6 and 7, the first transducer 10 and the second transducer 20 have transducer mounting plates 106 thereon, the transducer mounting plates 106 have holes for mounting the transducers in the middle, the transducer connector 40 includes a horizontal section 403 and inclined sections 402 disposed at both sides of the horizontal section 403, and the inclined sections 402 are fixedly connected to the transducer mounting plates 106 of the first transducer 10 and the second transducer 20 by fasteners 401. Preferably, the angle between the horizontal section 403 and the inclined section 402 is 135 degrees, and the angle between the two inclined sections 402 is 90 degrees, so as to ensure the orthogonality between the axes of the first transducer 10 and the second transducer 20.

Secondly, a deep hole surface strengthening method is also provided, the deep hole V-shaped ultrasonic shot blasting device is used, and the method comprises the following steps:

s1, selecting the shot blasting tool heads 30 with different sizes according to different hole diameters and hole depths, and realizing shot blasting reinforcement on deep holes with different diameters by replacing shot blasting parts 302 with different diameters;

s2, placing the shot blasting pellets 70 in the annular groove 303 of the shot blasting part 302; preferably, after the excitation component 306 is electrified, a magnetic field is generated on the shot-blasting portion 302 for adsorbing the shot-blasting pellets 70, and the shot-blasting portion 302 adsorbing the shot-blasting pellets 70 extends into the deep hole again, so that the shot-blasting pellets 70 can be prevented from falling off, and the shot filling is convenient. After the shot 302 extends into the recess, the exciter 306 is de-energized and the shot pellets 70 are free in the chamber 80.

S3, inserting the slender tool head 30 into the hole and staying at the bottom of the hole;

s4, applying voltage signals with a phase difference of pi/2 simple harmonic to the first transducer 10 and the second transducer 20 respectively;

and S5, controlling the slender tool head 30 to reciprocate along the axial direction of the hole to complete the surface strengthening of the inner wall 60 of the hole. Specifically, the speed of movement of the elongate tool head 30 may be determined by the frequency, amplitude, and size and material of the shot pellets 70.

Further, in order to ensure the shot blasting effect, it is ensured that a sufficient number of shot-blasting pellets 70 are applied to the inner wall 60 of the hole without restricting the movement of the shot-blasting pellets 70 due to an excessive number of shot-blasting pellets 70, and the number of shot-blasting pellets 70 is about 10% of the total volume between the peen part 302 and the inner wall 60 of the hole.

The invention realizes the plastic deformation of the metal surface by impacting the surface by utilizing the high-speed movement of the pill and can be used for strengthening the inner wall of the blind hole. This plastic deformation allows the formation of nanocrystalline grains, which alter the surface properties. The method has the main advantages that the method is purely mechanical, does not need any chemical or heat treatment, and can obtain a more compact surface through secondary shot blasting, reduce the roughness and improve the performance. After the ultrasonic shot blasting is finished, the shot does not need to be collected and cleaned, the shot can be recycled for multiple times, the ultrasonic shot blasting equipment is simple and easy to operate, the limitation of the appearance of the part is small, and shot blasting treatment of the part with the complex shape can be realized. The continuous, uniform and stable shot flow can be realized by controlling the shot flow to act on the shot blasting target.

The invention can simultaneously strengthen the inner wall of the deep hole in 360 degrees in the whole circumferential direction at one time, improves the surface strengthening efficiency, has high coverage rate and good shot blasting uniformity, can realize shot blasting on the inner wall of the blind hole, and enlarges the processing range.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. A deep hole V-shaped ultrasonic shot blasting device comprises a first transducer (10) and a second transducer (20), the main body parts of the first transducer (10) and the second transducer (20) are connected through a transducer connecting piece (40), the included angle between the axes of the first transducer (10) and the second transducer (20) is 90 degrees, the first transducer (10) and the second transducer (20) are identical in structure, amplitude-changing rods (105) are arranged in front of the first transducer (10) and the second transducer (20), the ends of the two amplitude-changing rods (105) are connected through a connecting block (50), an elongated tool head (30) is connected onto the connecting block (50), the axis of the elongated tool head (30) is orthogonal to the axes of the first transducer (10) and the second transducer (20), and a shot blasting portion (302) is arranged at the front end of the elongated tool head (30), the shot blasting part is provided with an annular groove (303), and the annular groove (303) and the inner wall (60) of the deep hole form a shot blasting cavity (80).

2. The deep-hole V-shaped ultrasonic shot blasting device according to claim 1, characterized in that: the first transducer (10) applies a first simple harmonic voltage signal, the second transducer (20) applies a second simple harmonic voltage signal, the phase difference between the first simple harmonic voltage signal and the second simple harmonic voltage signal is pi/2, the head of the slender tool head (30) generates n (n is not less than 0, n is an integer) order bending vibration, and the slender tool head (30) performs micro amplitude orbiting around the axis after the bending vibration is orthogonal.

3. The deep-hole V-shaped ultrasonic shot blasting device according to claim 2, characterized in that: the working frequency of the first transducer (10) and the second transducer (20) is more than or equal to 20 kHz.

4. The deep-hole V-shaped ultrasonic shot blasting device according to claim 1, characterized in that: the elongated tool head (30) has a shank body (301), the peen portion (302) is provided at an end of the shank body (301), the ring groove (303) of the peen portion (302) is formed by an upper flange (304), a head section (305), and a lower flange (306), and the diameter of the head section (305) is smaller than the diameters of the upper flange (304) and the lower flange (306).

5. The deep-hole V-shaped ultrasonic shot blasting device according to claim 4, wherein: the peen part (302) is detachably connected with the rod body (301).

6. The deep-hole V-shaped ultrasonic shot blasting device according to claim 5, wherein: the two ends of the rod body (301) are provided with threaded portions, the connecting block (50) is a rectangular block, and threaded holes are formed in three adjacent faces of the rectangular block respectively.

7. The deep-hole V-shaped ultrasonic shot blasting device according to claim 4, wherein: a gap is formed between the upper flange (304) and the lower flange (306) of the shot-peening section (302) and the inner wall (60) of the hole.

8. The deep-hole V-shaped ultrasonic shot blasting device according to claim 1, characterized in that: the transducer connection (40) comprises a horizontal section (403) and inclined sections (402) arranged on both sides of the horizontal section (403), the inclined sections (402) being used for mounting the first transducer (10) and the second transducer (20).

9. A deep hole surface strengthening method using the deep hole V-shaped ultrasonic shot blasting device according to any one of claims 1 to 8, comprising the steps of:

s1, selecting the shot blasting tool heads (30) with different sizes according to different hole diameters and hole depths;

s2, placing the shot blasting pellets (70) in the ring groove (303) of the shot blasting part (302);

s3, inserting the slender tool head (30) into the hole and staying at the bottom of the hole;

s4, respectively applying voltage signals with a phase difference of pi/2 simple harmonic to the first transducer (10) and the second transducer (20);

and S5, controlling the slender tool head (30) to reciprocate along the axial direction of the hole to finish the surface strengthening of the inner wall (60) of the hole.

10. The deep-hole V-shaped ultrasonic shot blasting device according to claim 9, wherein: in step S2, the shot pellets (70) are loaded in an amount of about 10% of the total volume between the peened portion (302) and the hole inner wall (60).