Actuator cylinder inner surface ultrasonic impact strengthening device and using method thereof

Abstract

The invention belongs to a part surface treatment technology, and relates to an actuator cylinder inner surface ultrasonic impact strengthening device and a use method thereof. Comprising an actuator cylinder upper cover plate (1), an actuator cylinder supporting table (2), an ultrasonic vibration head fastening screw (3), an ultrasonic impact device, an ultrasonic vibration head supporting platform (6), an ultrasonic working rotary table (8), a vertical lifting working table (9) and an ultrasonic strengthening working table base (10). According to the method, only a small amount of shots are consumed and are far less than traditional shot peening strengthening, the machining cost is lower, the dust amount is smaller, and noise is lower. In the strengthening process, a tool and actuator cylinder parts do not need to be moved, all the inner surfaces of the actuator cylinders are strengthened only through rotation of the ultrasonic working rotary table and lifting of the vertical lifting working table, high positioning precision is achieved, and the machining efficiency is remarkably improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of part surface treatment, and relates to an ultrasonic impact strengthening device for the inner surface of an actuator cylinder and a use method thereof. BACKGROUND

[0002] The inner wall of the actuator cylinder of the domestic aero-engine driving system faces the risk of fatigue and wear failure, becomes one of the "life limiting parts" of the aero-engine, and has attracted great attention. According to the accumulation in the processing technology of the actuator cylinder parts, at present, the surface strengthening process of the actuator cylinder parts is less carried out. The reason is that the actuator cylinder inner wall is similar to the blind hole type part, the cylinder diameter R is larger than the depth of the inner wall L, and the traditional shot peening strengthening faces the problems of structural interference and difficulty in removing the shot.

[0003] At present, the commonly used strengthening method for the inner wall of the actuator cylinder is the shot peening method, that is, a shot is driven by compressed gas to impact the surface of the part. However, the cylinder diameter R is larger than the depth of the inner wall L, the bottom region of the actuator cylinder is blocked by the structure, and it is difficult to be impacted by the shot. Therefore, the bottom region of the actuator cylinder is difficult to reach the shot peening strength specified in the drawing, thereby causing the shot peening strengthening effect of the inner surface of the actuator cylinder to be uneven, and causing the fatigue resistance effect of the shot peening to be unable to reach the expectation.

[0004] Meanwhile, the ultrasonic impact strengthening method has not been used in the actuator cylinder type part. According to the CN115094215B, the tenon and groove ultrasonic impact strengthening method is adopted, the tenon and groove are vertically placed, the vibration head is on the bottom surface, and the tenon and groove are closed to form an ultrasonic shot closed cavity on both sides, so as to complete the ultrasonic impact strengthening of the tenon and groove. However, according to the simulation and actual strengthening, the coverage rate of the tenon and groove surface is detected. Due to the structural interference, the shot coverage rate on the stress surface (failure concentration position) of the tenon and groove is poor, and the coverage rate on the non-stress surface of the tenon is good. Therefore, the strengthening uniformity of the tenon and groove teeth is poor, and the fatigue performance is poor. SUMMARY

[0005] The purpose of the application is to provide an ultrasonic impact strengthening device for the inner surface of an actuator cylinder and a use method thereof, so as to overcome the problem of poor shot accessibility of the actuator cylinder, and improve the uniformity of the strengthening effect of the inner wall of the actuator cylinder.

[0006] The technical scheme of the application is: An ultrasonic impact strengthening device for the inner surface of an actuator cylinder, characterized in that: The device comprises an actuator cylinder upper cover plate 1, an actuator cylinder support table 2, an ultrasonic vibration head fastening screw 3, an ultrasonic impact device, an ultrasonic vibration head support platform 6, an ultrasonic working turntable 8, a vertical lifting workbench 9 and an ultrasonic strengthening workbench base 10; wherein the actuator cylinder 4 is installed on the actuator cylinder support table 2 and fixed by the actuator cylinder upper cover plate 1 and the fastening screw, the actuator cylinder support table 2 is installed on and fixed to the ultrasonic strengthening workbench base 10; the ultrasonic impact device is composed of an ultrasonic impact head 5 and an ultrasonic impact generator 7, the ultrasonic impact head 5 extends into the actuator cylinder 4 to form a closed cavity with the inner wall and bottom surface of the actuator cylinder 4, and ultrasonic impact strengthening of the bottom surface and side surface of the actuator cylinder 4 is realized by vibration of the ultrasonic impact head 5; the profiling amplitude rod 701 of the ultrasonic impact generator 7 is connected with the ultrasonic impact head 5; the ultrasonic vibration head is fixed to the ultrasonic vibration head support platform 6 through the ultrasonic vibration head fastening screw 3, the ultrasonic vibration head support platform 6 is installed on the ultrasonic working turntable 8 and rotates with the ultrasonic working turntable 8; the ultrasonic working turntable 8 is connected in the vertical lifting workbench 9.

[0007] The ultrasonic impact head 5 is in a columnar structure as a whole, and the upper end is provided with a top surface projectile groove 501 and a side surface projectile groove 502, The gap between the outer cylindrical end surface of the ultrasonic impact head 5 and the inner end surface of the actuator cylinder 4 is 0.3 mm.

[0008] The ultrasonic impact head 5 is coaxial with the inner surface of the actuator cylinder 4.

[0009] The height d1 of the side surface projectile groove 502 of the ultrasonic impact head 5 is 5 cm to 20 cm, the depth d2 is 5 mm to 10 mm, and the depth d3 of the top surface projectile groove 501 is 5 mm to 10 mm.

[0010] The ultrasonic impact generator 7 is composed of a profiling amplitude rod 701, a transducer 702 and a cooling device 703, and the profiling amplitude rod 701, the transducer 702 and the cooling device 703 are connected in sequence.

[0011] The ultrasonic wave frequency generated by the transducer 702 is 20 to 25 KHz, and the resonance frequency of the profiling amplitude rod 701 is 18 to 21 KHz.

[0012] An ultrasonic impact strengthening method of an ultrasonic impact strengthening device for the inner surface of an actuator cylinder comprises the following steps: (1) The actuator cylinder 4 is vertically installed on the actuator cylinder support table 2 with the bottom surface downward and is pressed by the actuator cylinder upper cover plate 1; at the same time, the ultrasonic impact head 5 is connected with the ultrasonic impact generator 7, and the ultrasonic vibration head is fixed on the ultrasonic vibration head support platform 6 through the ultrasonic vibration head fastening screw 3; (2) First, the projectile is put into the top surface projectile groove 501 of the ultrasonic impact head 5, the vertical lifting workbench 9 is operated to make the ultrasonic impact head 5 rise, and the top surface projectile groove 501 forms a closed projectile cavity with the bottom region of the actuator cylinder; (3) Turn on the power, the ultrasonic impact head 5 does high-speed up and down reciprocating motion under the drive of ultrasonic waves, and drives the projectile to impact the bottom area of the actuator cylinder; (4) After the strengthening is completed, turn off the power, lower the vertical lifting workbench 9, take out the projectile in the top projectile groove 501, put the projectile in the side projectile groove 502, control the vertical lifting workbench 9 to make the ultrasonic impact head 5 rise, and the side projectile groove 502 forms a closed projectile cavity with the side area of the actuator cylinder 4. (5) Turn on the power, the ultrasonic impact head 5 does high-speed up and down reciprocating motion under the drive of ultrasonic waves, and drives the projectile to impact the side area of the actuator cylinder. (6) The rotation speed of the ultrasonic working turntable 8 and the moving speed of the vertical lifting workbench 9 are set, and the side projectile groove 502 is realized to be spirally scanned from top to bottom on the sidewall of the actuator cylinder.

[0013] (7) After the strengthening is completed, turn off the power, lower the ultrasonic impact head 5, and remove the actuator cylinder upper cover plate 1 and the actuator cylinder 4.

[0014] When the bottom area of the actuator cylinder is strengthened, the distance between the top surface of the ultrasonic impact head 5 and the bottom surface of the actuator cylinder is not greater than d3; when the sidewall area of the actuator cylinder is strengthened, the moving speed v of the vertical lifting workbench 9 and the rotation speed r of the ultrasonic working turntable 8 satisfy d1 / v≥360 / r.

[0015] The projectiles are spherical in shape, the number is 10-30, the diameter is Φ0.6mm, the material is ceramic pellets or cast steel pellets, and the hardness is HRC55-62.

[0016] The advantages of the present application are: (1) The disadvantages of actuator cylinder structure interference and poor projectile accessibility are overcome, the bottom and side of the actuator cylinder are respectively formed into a closed projectile cavity with the ultrasonic vibration head, the projectiles are made to do high-speed Brownian motion in the cavity, the inner wall and bottom surface of the actuator cylinder are impacted by the projectiles without difference, and uniform strengthening effect is obtained in each part of the actuator cylinder.

[0017] (2) The method only consumes a small amount of projectiles (10-80), which is much less than traditional shot peening, has lower processing cost, less dust and smaller noise.

[0018] (3) During the strengthening process, the workpiece and the actuator cylinder part do not need to be moved, and the entire inner surface of the actuator cylinder is strengthened only by the rotation of the ultrasonic working turntable 8 and the lifting of the vertical lifting workbench 9, which not only has high positioning accuracy, but also significantly improves the processing efficiency.

[0019] (4) According to an embodiment of the present application, test proves that, compared with traditional shot peening, the maximum difference value of residual compressive stress on the surface of the actuator cylinder wall after the strengthening is reduced by 300% than that of shot peening. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 Overall schematic diagram of the device; Figure 2 Schematic diagram of an ultrasonic impact generator; Figure 3 Schematic diagram of an ultrasonic impact head; Figure 4 Schematic diagram of the cavity of the 501 projectile; Figure 5 A schematic diagram of the cavity of the 502 projectile. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments: An ultrasonic impact strengthening device for the inner surface of an actuated cylinder includes an actuated cylinder cover plate 1, an actuated cylinder support platform 2, ultrasonic vibration head fastening screws 3, an actuated cylinder 4, an ultrasonic impact head 5, an ultrasonic vibration head support platform 6, an ultrasonic impact generator 7, an ultrasonic working turntable 8, a vertical lifting worktable 9, and an ultrasonic strengthening worktable base 10. The actuated cylinder 4 is mounted on the actuated cylinder support platform 2 and fixed to it by the actuated cylinder cover plate 1 and fastening screws. The actuated cylinder support platform 2 is mounted on and fixed to the ultrasonic strengthening worktable base 10. The ultrasonic impact device consists of the ultrasonic impact head 5 and the ultrasonic impact generator 7, which are fixed to the ultrasonic vibration head support platform 6 by the ultrasonic vibration head fastening screws 3. The ultrasonic vibration head support platform 6 is mounted on the ultrasonic working turntable 8 and rotates with the ultrasonic working turntable 8. The ultrasonic working turntable 8 is connected to the vertical lifting worktable 9, allowing for vertical movement.

[0022] The ultrasonic impact head 5 and the inner wall of the actuator cylinder 4 form a closed cavity, namely the top surface shot groove 501 and the side shot groove 502. The ultrasonic impact strengthening of the bottom and side surfaces of the actuator cylinder 4 is achieved by the vibration of the ultrasonic impact head 5.

[0023] The gap between the outer cylindrical end face of the ultrasonic impact head 5 and the inner end face of the actuator cylinder 4 is 0.3mm.

[0024] The ultrasonic impact head 5 is coaxial with the inner surface of the actuating cylinder 4 and is vertically upward.

[0025] Based on the simulation results of ultrasonic impact strengthening of the inner side and bottom structure of the actuator cylinder 4, in order to make the strengthening effect of the inner side of the actuator cylinder 4 more uniform, the height d1 of the side shot groove 502 is 10mm~40mm, the depth d2 is 5mm~10mm, and the depth d3 of the top shot groove 501 is 5mm~10mm.

[0026] The ultrasonic shock generator 7 consists of a contoured amplitude transformer 701, a transducer 702, and a cooling device 703. The ultrasonic frequency generated by the transducer 702 is 20-25KHz, and the resonant frequency of the amplitude transformer is 18-21KHz.

[0027] The ultrasonic impact strengthening method of the ultrasonic impact strengthening device for the inner surface of an actuator cylinder according to claim 1 comprises the following steps: (1) The actuator cylinder 4 is vertically installed on the actuator cylinder support table 2 with the bottom surface facing downwards and is pressed by the actuator cylinder upper cover plate 1. At the same time, the ultrasonic impact head 5 is connected with the ultrasonic impact generator 7 and is fixed on the ultrasonic vibration head support platform 6 through the ultrasonic vibration head fastening screw 3; (2) Firstly, the pellets are put into the 501 top surface pellet groove of the ultrasonic impact head 5, the vertical lifting workbench 9 is operated to make the ultrasonic impact head 5 rise, and the 501 top surface pellet groove forms a closed pellet cavity with the bottom area of the actuator cylinder; (3) The power is turned on, the ultrasonic impact head 5 is driven to make high-speed up-and-down reciprocating motion under the ultrasonic wave, and the pellets are driven to impact the bottom area of the actuator cylinder; (4) After the strengthening is completed, the power is turned off, the vertical lifting workbench 9 is lowered, the pellets in the 501 top surface pellet groove are taken out, the pellets are put into the side pellet groove 502, the vertical lifting workbench 9 is operated to make the ultrasonic impact head 5 rise, and the side pellet groove 502 forms a closed pellet cavity with the side area of the actuator cylinder; (5) The power is turned on, the ultrasonic impact head 5 is driven to make high-speed up-and-down reciprocating motion under the ultrasonic wave, and the pellets are driven to impact the side area of the actuator cylinder; (6) The rotation speed of the ultrasonic work turntable 8 and the moving speed of the vertical lifting workbench 9 are set to realize the spiral scanning of the 502 side pellet groove in the sidewall of the actuator cylinder from top to bottom.

[0028] (7) After the strengthening is completed, the power is turned off, the ultrasonic impact head 5 is lowered, and the actuator cylinder upper cover plate 1 and the actuator cylinder 4 are removed.

[0029] When the bottom area of the actuator cylinder is strengthened, the distance between the top surface of the ultrasonic impact head 5 and the bottom surface of the actuator cylinder should be less than or equal to d3; when the sidewall area of the actuator cylinder is strengthened, the moving speed v of the vertical lifting workbench 9 and the rotation speed r of the ultrasonic work turntable 8 should satisfy d1 / v≤1 / r.

[0030] The pellets are spherical in shape, the number is 10-30, the diameter is Φ0.6mm, the material is ceramic pellets or cast steel pellets, and the hardness is HRC55-62.

[0031] The working principle of the present application is: Ultrasonic wave has the advantages of high frequency, high energy and high power density, and is one of ideal power sources for high-energy surface strengthening. Therefore, the patent utilizes the movement of hard projectiles in the ultrasonic source excited cavity to form a closed cavity on the inner wall of the semi-open actuator cylinder by cooperating with the vibration head, and then places hard projectiles in the cavity. The projectiles impact the inner wall of the cavity at high speed under the excitation of ultrasonic waves, so that the surface of the inner wall is plastically deformed to realize surface strengthening. Since the projectiles make Brownian motion in the cavity, the number and intensity of impacts of the projectiles on each part of the inner wall of the actuator cylinder are the same, so the strengthening effect of the surface of the inner wall of the actuator cylinder is uniform, thereby solving the problem of structural interference.

[0032] Embodiment: The actuator cylinder processed in the embodiment has a height of 180mm and an inner cylinder diameter of 30mm. The bottom surface of the actuator cylinder 4 is vertically installed on the actuator cylinder support table 2 with the bottom surface facing downward, and is pressed by the actuator cylinder upper cover plate 1. At the same time, the ultrasonic impact head 5 is connected with the ultrasonic impact generator 7, and is fixed on the ultrasonic vibration head support platform 6 through the ultrasonic vibration head fastening screw 3. The projectiles are placed in the 501 top surface projectile groove of the ultrasonic impact head 5, the depth of the 501 top surface projectile groove is 5mm, the vertical lifting workbench 9 is operated to make the ultrasonic impact head 5 rise, and the 501 top surface projectile groove and the bottom region of the actuator cylinder form a closed projectile cavity with a height of 15mm. The power is turned on, the ultrasonic impact head 5 makes high-speed up-and-down reciprocating motion under the driving of ultrasonic waves, and drives the projectiles to impact the bottom region of the actuator cylinder. After the strengthening is completed, the power is turned off, the vertical lifting workbench 9 is lowered, and the projectiles in the 501 top surface projectile groove are taken out.

[0033] The projectiles are placed in the side surface projectile groove 502, the height d1 of the side surface projectile groove 502 is 30mm, and the depth d2 is 5mm. The vertical lifting workbench 9 is operated to make the ultrasonic impact head 5 rise, and the side surface projectile groove 502 and the side surface region of the actuator cylinder form a closed projectile cavity. The power is turned on, the ultrasonic impact head 5 makes high-speed up-and-down reciprocating motion under the driving of ultrasonic waves, and drives the projectiles to impact the side surface region of the actuator cylinder. The rotation speed r of the ultrasonic work turntable 8 is set to 3rpm, the downward movement speed v of the vertical lifting workbench 9 is 1mm / s, and the side surface projectile groove 502 is realized to be spirally scanned on the sidewall of the actuator cylinder from top to bottom. After the strengthening is completed, the power is turned off, the ultrasonic impact head 5 is lowered, and the actuator cylinder upper cover plate 1 and the actuator cylinder 4 are removed. The surface dust is cleaned by compressed gas, and the surface is cleaned by alcohol or acetone before packaging.

Claims

1. An apparatus for ultrasonic impact hardening of an inner surface of a cylinder, characterized in that: The device comprises an actuator upper cover plate (1), an actuator support table (2), an ultrasonic vibration head fastening screw (3), an ultrasonic impact device, an ultrasonic vibration head support platform (6), an ultrasonic working turntable (8), a vertical lifting workbench (9) and an ultrasonic strengthening workbench base (10); wherein the actuator (4) is installed on the actuator support table (2) and fixed by the actuator upper cover plate (1) and the fastening screw, the actuator support table (2) is installed on and fixed to the ultrasonic strengthening workbench base (10); the ultrasonic impact device is composed of an ultrasonic impact head (5) and an ultrasonic impact generator (7), the ultrasonic impact head (5) extends into the actuator (4) to form a closed cavity with the inner wall and bottom surface of the actuator (4), and ultrasonic impact strengthening of the bottom surface and side surface of the actuator (4) is realized by vibration of the ultrasonic impact head (5); the profiling amplitude bar (701) of the ultrasonic impact generator (7) is connected to the ultrasonic impact head (5); the ultrasonic vibration head support platform (6) is fixed to the ultrasonic vibration head fastening screw (3), the ultrasonic vibration head support platform (6) is installed on the ultrasonic working turntable (8) and rotates with the ultrasonic working turntable (8); the ultrasonic working turntable (8) is connected in the vertical lifting workbench (9).

2. The device for ultrasonic impact treatment of the inner surface of a cylinder according to claim 1, characterized in that: The ultrasonic impact head (5) is in a columnar structure, and the top surface projectile groove (501) and the side surface projectile groove (502) are arranged at the upper end.

3. The device for ultrasonic impact treatment of the inner surface of a cylinder according to claim 1, characterized in that it comprises: The gap between the outer cylindrical end surface of the ultrasonic impact head (5) and the inner end surface of the actuator (4) is 0.3 mm.

4. The device for ultrasonic impact treatment of the inner surface of a cylinder according to claim 1, characterized in that: The ultrasonic impact head (5) is coaxial with the inner surface of the actuator (4).

5. The device for ultrasonic impact treatment of the inner surface of a cylinder according to claim 2, characterized in that: The height d1 of the side surface projectile groove (502) of the ultrasonic impact head (5) is 5-20 cm, the depth d2 is 5-10 mm, and the depth d3 of the top surface projectile groove (501) is 5-10 mm.

6. The device for ultrasonic impact treatment of the inner surface of a cylinder according to claim 1, characterized in that: The ultrasonic impact generator (7) is composed of a profiling amplitude bar (701), a transducer (702) and a cooling device (703), which are connected in sequence.

7. The device for ultrasonic impact treatment of the inner surface of a cylinder according to claim 1, characterized in that it comprises: The ultrasonic wave frequency generated by the transducer (702) is 20-25 KHz, and the resonance frequency of the profiling amplitude bar (701) is 18-21 KHz.

8. The ultrasonic impact strengthening method of the device for ultrasonic impact strengthening of the inner surface of a cylinder according to any one of claims 1 to 7, characterized in that, The method comprises the following steps: (1) vertically install the actuator (4) bottom surface downward on the actuator support table (2), and press tightly by the actuator upper cover plate (1); at the same time, connect the ultrasonic impact head (5) with the ultrasonic impact generator (7), and fix on the ultrasonic vibration head support platform (6) by the ultrasonic vibration head fastening screw (3); (2) first put the projectile into the top surface projectile groove (501) of the ultrasonic impact head (5), and operate the vertical lifting workbench (9) to make the ultrasonic impact head (5) rise, so that the top surface projectile groove (501) forms a closed projectile cavity with the actuator bottom region; (3) turn on the power, and the ultrasonic impact head (5) makes high-speed up-and-down reciprocating motion under the drive of ultrasonic wave, and drives the projectile to impact the actuator bottom region; (4) After the strengthening is completed, the power is turned off, the vertical lifting workbench (9) is lowered, the pellets in the top pellet groove (501) are taken out, the pellets are put into the side pellet groove (502), the vertical lifting workbench (9) is operated to make the ultrasonic impact head (5) rise, and the side pellet groove (502) forms a closed pellet cavity with the side area of the actuator cylinder (4); (5) The power is turned on, the ultrasonic impact head (5) is driven to make high-speed up-and-down reciprocating motion under the driving of ultrasonic waves, and the pellets are driven to impact the side area of the actuator cylinder; (6) The rotation speed of the ultrasonic working turntable (8) and the moving speed of the vertical lifting workbench (9) are set, and the side pellet groove (502) is realized to spiral scan on the sidewall of the actuator cylinder from top to bottom. (7) After the strengthening is completed, the power is turned off, the ultrasonic impact head (5) is lowered, and the actuator cylinder upper cover plate (1) and the actuator cylinder (4) are removed.

9. The ultrasonic impact strengthening method of the ultrasonic impact strengthening device for the inner surface of the actuator cylinder according to claim 8, characterized in that: When the bottom area of the actuator cylinder is strengthened, the distance between the top surface of the ultrasonic impact head (5) and the bottom surface of the actuator cylinder is not greater than d3; when the sidewall area of the actuator cylinder is strengthened, the moving speed v of the vertical lifting workbench (9) and the rotation speed r of the ultrasonic working turntable (8) satisfy d1 / v≥360 / r.

10. The ultrasonic impact strengthening method of the ultrasonic impact strengthening device for the inner surface of the actuator cylinder according to claim 8, characterized in that: The pellets are spherical in shape, the number is 10-30, the diameter is Φ0.6 mm, the material is ceramic pellets or cast steel pellets, and the hardness is HRC55-62.

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