Ultrasonic transducer assembly tool and assembly method

Abstract

The present invention discloses an ultrasonic transducer assembly tool, which includes a bracket, a servo motor, a torque mechanism and a clamping and centering mechanism; the torque mechanism includes a rotating shaft, a torsion sleeve, a torsion sleeve and a torsion spring, the torsion spring and the torsion sleeve are both sleeved on the rotating shaft, one end of the torsion spring is fixedly connected to the rotating shaft, and the other end is fixedly connected to the torsion sleeve, the torsion sleeve is located at the end of the rotating shaft and is connected to the torsion sleeve; the rotating shaft is rotatably arranged on the bracket through a bearing fixing seat, and the servo motor is used to drive the rotating shaft to rotate; the clamping and centering mechanism includes two symmetrically arranged clamping arms, each of which is provided with a guide groove opening toward the other clamping arm, and the guide groove is provided with a positioning block and a compression spring for providing elastic force to the positioning block. The present invention uses an automated method to achieve the centering of the transducer piezoelectric ceramic plate and the torque control of the bolt tightening, saving labor and making the assembly process more controllable.

Description

Technical Field

[0001] The invention relates to an ultrasonic transducer assembly tool and an assembly method, belonging to the technical field of ultrasonic transducers. Background Art

[0002] As a crucial component of an ultrasonic surgical system, the performance of the ultrasonic transducer directly impacts the overall system's effectiveness. The transducer primarily consists of a front cover, a rear cover, a piezoelectric ceramic sheet, electrodes, and bolts. The connection structure is described in Patent Document 1 (Publication No. CN113689838A). During transducer production, the assembly process for its core component, the ultrasonic vibrator (piezoelectric ceramic sheet), significantly impacts its performance. During assembly, ensuring the coaxiality of all assembled components is paramount; otherwise, the vibrator's efficiency will be reduced. Dimensional deviations in the ceramic sheet also affect assembly concentricity. Controlling the vibrator's preload is also crucial. Excessive or insufficient preload can cause the ceramic to break during use, and inappropriate preload can also reduce its efficiency. Improving transducer assembly efficiency and quality is also crucial for enhancing product competitiveness. Summary of the Invention

[0003] In order to improve the efficiency and quality of ultrasonic transducer assembly, the present invention provides an ultrasonic transducer assembly tool, and the specific technical solution is as follows.

[0004] An ultrasonic transducer assembly tool, characterized by comprising a bracket, a servo motor, a torque mechanism and a clamping and centering mechanism;

[0005] The torsion mechanism includes a rotating shaft, a torsion sleeve, a torsion sleeve and a torsion spring. The torsion spring and the torsion sleeve are both sleeved on the rotating shaft. One end of the torsion spring is fixedly connected to the rotating shaft, and the other end is fixedly connected to the torsion sleeve. The torsion sleeve is located at the end of the rotating shaft and is connected to the torsion sleeve. The rotating shaft is rotatably arranged on the bracket through a bearing fixing seat, and the servo motor is used to drive the rotating shaft to rotate.

[0006] The clamping and centering mechanism includes two symmetrically arranged clamping arms, each of which is provided with a guide groove opening toward the other clamping arm, and a positioning block and a compression spring for providing elastic force to the positioning block are provided in the guide groove. The compression springs and positioning blocks in the two clamping arms are exactly the same, and at least a portion of the positioning block is located outside the guide groove.

[0007] Using the above technical solution, the servo motor drives the rotating shaft to rotate, and the rotating shaft drives the torsion spring to twist, thereby providing torque for the torsion sleeve, and the torsion sleeve drives the torsion sleeve to tighten the bolts of the ultrasonic transducer; the two clamping arms of the clamping and centering mechanism clamp and fix the front cover of the transducer, and the positioning block in the clamping arm aligns the piezoelectric ceramic piece of the transducer under the action of the spring, ensuring that all piezoelectric ceramic pieces, bolts and front cover are in a coaxial state.

[0008] Furthermore, a torque sensor is installed between the torsion sleeve and the torque sleeve. The torque sensor can provide real-time feedback of the torque applied to the transducer bolt.

[0009] Furthermore, the rotating shaft is provided with a bearing, and the bracket is provided with a bearing retainer, wherein the bearing is assembled within the bearing retainer; the bearing retainer is fixed to the slide rail of the bracket. Preferably, the bracket is also provided with a quick-action clamp, which is used to drive the bearing retainer to switch between two positions. The quick-action clamp can be a quick-action clamp from the prior art (publication number CN208744627U), which facilitates the movement of the bearing retainer and remains self-locking once in place, preventing it from easily moving.

[0010] Furthermore, the rotating shaft comprises a round shaft portion and a square shaft portion, the servo motor has a square through-hole, and the square shaft portion passes through the square through-hole. This arrangement eliminates the need for a transmission device between the servo motor and the rotating shaft, allowing the servo motor to directly drive the rotating shaft, and ensuring axial movement of the rotating shaft along its own axis.

[0011] Furthermore, the positioning block has an arc-shaped abutting surface. Since the piezoelectric ceramic piece is circular, in order to better achieve the centering of the piezoelectric ceramic piece relative to the bolt, the arc-shaped abutting surface abuts against the piezoelectric ceramic piece, which makes it easier to achieve centering.

[0012] Based on the same inventive concept, the present invention also relates to an ultrasonic transducer assembly method, which uses the above-mentioned ultrasonic transducer assembly tool. The ultrasonic transducer assembly tool also includes an interconnected control system and a voltage signal acquisition and processing system. The voltage signal acquisition and processing system is used to monitor the voltage of the two stages of the piezoelectric ceramic stack of the transducer. It is characterized by mainly comprising the following steps:

[0013] Clamp the ultrasonic transducer between the two clamping arms of the clamping and centering mechanism, lower the torque mechanism and put the torque sleeve on the bolt head of the transducer;

[0014] A) Preliminary preloading mode: The servo motor rotates at a constant speed V1 and automatically enters the preloading mode when the preset torque Q1 is detected;

[0015] B) Preload mode: The servo motor rotates at a speed of V2 and stops when it reaches the preset torque Q2. At this time, the voltage between the two poles of the piezoelectric ceramic stack is U1, and the distance between U1 and the target value U is B1. When B1 is within the preset range, it enters the next mode.

[0016] C) Final assembly mode: The servo motor stays for a period of time T after each feed of a certain angle A. The voltage signal U2 between the two poles of the piezoelectric ceramic stack is tested. The voltage change of the piezoelectric ceramic stack caused by the motor rotation angle A is B2, B2≤1 / 3B1. The value of the rotation angle A decreases proportionally with the decrease of the value of U-U2. After 2 or more feeds, when the difference between U2 and U is less than the preset value, the assembly is completed.

[0017] By collecting the voltage signal between the two poles of the piezoelectric ceramic stack and processing and calculating it, the pressure value of the bolt can be estimated. The specific estimation process can be found in the applicant's prior application (application number: CN202110589135.6), which will not be repeated here.

[0018] The technical effect of the present invention is that the centering of the transducer piezoelectric ceramic piece and the torque control of the bolt tightening are achieved in an automated manner, which saves labor and makes the assembly process more controllable. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic diagram of an ultrasonic transducer assembly device of the present invention;

[0020] Figure 2 It is a three-dimensional schematic diagram of the ultrasonic transducer assembly tool of the present invention;

[0021] Figure 3 is a front view of the ultrasonic transducer assembly tool of the present invention;

[0022] Figure 4 is a schematic diagram of the torque mechanism;

[0023] Figure 5 Schematic diagram of clamping and centering of the clamping and centering mechanism;

[0024] Figure 6 is a schematic diagram of the transducer.

[0025] In the figure: bracket 1, servo motor 2, torque mechanism 3, rotating shaft 31, round shaft portion 311, square shaft portion 312, torsion sleeve 32, torque sleeve 33, torsion spring 34, bearing 35, clamping and centering mechanism 4, clamping arm 41, guide groove 42, positioning block 43, compression spring 44, bearing fixing seat 5, torque sensor 6, transducer 7, piezoelectric ceramic piece 71, bolt 72, front cover plate 73, electrode 74, slide rail 8, quick clamp 9, control system 10. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below with reference to the accompanying drawings.

[0027] See also Figures 1-6 , an ultrasonic transducer assembly tool, which includes a bracket 1, a servo motor 2, a torque mechanism 3 and a clamping and centering mechanism 4; the structure of the transducer is as follows Figure 6 As shown, it mainly includes a front cover plate 73, piezoelectric ceramic sheets 71 and bolts 72. The front cover plate 73 has screw holes (not shown), and the bolts 72 are threadedly connected to the screw holes. The piezoelectric ceramic sheets 71 are sleeved on the bolts 72. There are electrodes 74 between adjacent piezoelectric ceramic sheets 71. By tightening the bolt heads of the bolts 72, the piezoelectric ceramic sheets 71 and the electrodes 74 are fastened together to form a piezoelectric ceramic stack.

[0028] The torsion mechanism 3 includes a rotating shaft 31, a torsion sleeve 32, a torsion sleeve 33 and a torsion spring 34. The torsion spring 34 and the torsion sleeve 32 are both sleeved on the rotating shaft 31. One end of the torsion spring 34 is fixedly connected to the rotating shaft 31, and the other end is fixedly connected to the torsion sleeve 32. The torsion sleeve 33 is located at the end of the rotating shaft 31 and the torsion sleeve 33 is connected to the torsion sleeve 32. The rotating shaft 31 is rotatably arranged on the bracket 1 through the bearing fixing seat 5, and the servo motor 2 is used to drive the rotating shaft 31 to rotate. Preferably, the rotating shaft 31 includes a round shaft portion 311 and a square shaft portion 312, and the servo motor 2 has a square through hole ( Not shown), the square shaft portion 312 passes through a square through-hole. This arrangement can eliminate the need for a transmission device between the servo motor 2 and the rotating shaft 31, allowing the servo motor 2 to directly drive the rotating shaft 31 to rotate, and can satisfy the axial movement of the rotating shaft 31 along its own axis; a torque sensor 6 is installed between the torsion sleeve 32 and the torque sleeve 33, and the torque sensor 6 can provide real-time feedback on the torque applied to the transducer bolt; by providing a torsion spring 34, the torque of the servo motor can be applied to the bolt 72 of the transducer 7 in a gentle manner, avoiding a strong impact on the piezoelectric ceramic piece 71. The servo motor is conducive to achieving precise control and feedback, and can feed back the parameters of the servo motor during operation to the control system, and control the output torque and speed by controlling the voltage and current of the servo motor.

[0029] The clamping and centering mechanism 4 includes two symmetrically arranged clamping arms 41. Each clamping arm 41 is provided with a guide slot 42 that opens toward the other clamping arm 41. A positioning block 43 and a compression spring 44 for providing elastic force to the positioning block 43 are disposed within the guide slot 42. The compression spring 44 and positioning block 43 within the two clamping arms 41 are identical (i.e., the parameters of the compression spring 44 are identical, and the size and weight of the positioning block 43 are also identical). At least a portion of the positioning block 43 is located outside the guide slot 42. Preferably, the positioning block 43 has an arc-shaped abutment surface (not shown) that faces the piezoelectric ceramic disc 71 of the transducer 7. Because the piezoelectric ceramic disc is circular, centering the piezoelectric ceramic disc relative to the bolt 72 is facilitated when the arc-shaped abutment surface abuts the piezoelectric ceramic disc 71. The two clamping arms 41 move synchronously relative to the center of the transducer, i.e., they move at the same speed but in opposite directions. The two clamping arms 41 can be placed on a screw-nut mechanism, and a motor can be used to drive the opening and closing of the two clamping arms 41. This is a prior art technique and will not be described in detail here. When the two clamping arms 41 clamp the front cover 73 of the transducer 7, the positioning block 43 pushes the piezoelectric ceramic disc 71 under the elastic force of the compression spring 44. Since the elastic force of the compression spring 44 in the two clamping arms 41 is the same, the piezoelectric ceramic disc 71 is coaxial with the bolt 72, achieving coaxial alignment. Of course, the premise is that the center of the two clamping arms 41 coincides with the center of the bolt 72.

[0030] To enable rotation and vertical movement of the rotating shaft 31, a bearing 35 is provided on the rotating shaft 31. A bearing holder 5 is provided on the bracket 1. The bearing 35 is assembled within the bearing holder 5. The bearing holder 5 is fixed to the slide rail 8 of the bracket 1. Preferably, a quick-action clamp 9 is also provided on the bracket 1 to actuate the bearing holder 5 between two vertical positions. The quick-action clamp 9 can be a quick-action clamp 9 from the prior art (publication number CN208744627U). The quick-action clamp 9 facilitates movement of the bearing holder 5 and, once in position, remains self-locking, preventing it from easily moving.

[0031] When assembling the transducer, the two clamping arms 41 of the clamping and centering mechanism 4 clamp and fix the front cover 73 of the transducer, and the positioning block 43 in the clamping arm 41 aligns the piezoelectric ceramic piece 71 of the transducer under the action of the spring, ensuring that all piezoelectric ceramic pieces 71, bolts 72 and front cover 73 are in a coaxial state; the torque mechanism 3 is moved downward by the quick clamp 9, and the torque sleeve 33 is put on the bolt head of the transducer 7, and the servo motor 2 is started. The servo motor 2 drives the rotating shaft 31 to rotate, and the rotating shaft 31 drives the torsion spring 34 to twist, thereby providing torque for the torsion sleeve 32, and the torsion sleeve 32 drives the torque sleeve 33 to tighten the bolts of the ultrasonic transducer.

[0032] The present invention also relates to an ultrasonic transducer assembly method, which uses the above-mentioned ultrasonic transducer assembly tool. The ultrasonic transducer assembly tool also includes an interconnected control system 10 and a voltage signal acquisition and processing system (not shown). The voltage signal acquisition and processing system is used to monitor the voltage of the two stages of the piezoelectric ceramic stack of the transducer 7. The method mainly includes the following steps:

[0033] Clamp the ultrasonic transducer between the two clamping arms 41 of the clamping and centering mechanism 4, lower the torque mechanism 3 and put the torque sleeve 33 on the bolt head of the transducer 7;

[0034] A) Preliminary preloading mode: The servo motor 2 rotates at a constant speed V1 and automatically enters the preloading mode when the preset torque Q1 is detected;

[0035] B) Preload mode: The servo motor 2 rotates at a speed V2 and stops when it reaches the preset torque Q2. At this time, the voltage between the two poles of the piezoelectric ceramic stack is U1, and the distance between U1 and the target value U is B1. When B1 is within the preset range, it enters the next mode;

[0036] C) Final assembly mode: Servo motor 2 advances a certain angle A and then pauses for a period of time, T, to measure the voltage signal U2 between the two electrodes of the piezoelectric ceramic stack. The change in the piezoelectric ceramic stack voltage caused by the motor's rotation angle A is B2, with B2 ≤ 1 / 3B1. The rotation angle A decreases proportionally with the decrease in the value of U-U2. After two or more advances, assembly is completed when the difference between U2 and U is less than the preset value. After a period of time, servo motor 2 returns to a state where the sensor torque is zero.

[0037] Among them, V1 is greater than V2, that is, the speed of the first stage is greater than the speed of the second stage; the value of the rotation angle A decreases proportionally with the decrease of the U-U2 value, which means: A'=A*((U-U2) / (U-U1)), or A''=A'*((U-U2') / (U-U2)), among which A' is the next feed relative to A, A'' is the next feed relative to A', and U2' is the voltage corresponding to the A' feed.

[0038] By collecting the voltage signal between the two poles of the piezoelectric ceramic stack and processing and calculating it, the pressure value of the bolt can be estimated. The specific estimation process can be found in the applicant's prior application (application number: CN202110589135.6), which will not be repeated here.

[0039] The embodiments of the present invention are described above in conjunction with the accompanying drawings. The embodiments of the present invention and the features thereof may be combined with each other unless there is any conflict. The present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Under the guidance of the present invention, those skilled in the art may devise various forms without departing from the spirit of the present invention and the scope of protection of the claims. All of these forms fall within the scope of protection of the present invention.

Claims

1. An ultrasonic transducer assembly tool, characterized in that: It includes a bracket (1), a servo motor (2), a torque mechanism (3) and a clamping and centering mechanism (4); The torsion mechanism (3) comprises a rotating shaft (31), a torsion sleeve (32), a torsion sleeve (33) and a torsion spring (34); the torsion spring (34) and the torsion sleeve (32) are both sleeved on the rotating shaft (31); one end of the torsion spring (34) is fixedly connected to the rotating shaft (31), and the other end is fixedly connected to the torsion sleeve (32); the torsion sleeve (33) is located at the end of the rotating shaft (31) and the torsion sleeve (33) is connected to the torsion sleeve (32); the rotating shaft (31) is rotatably arranged on the bracket (1) through a bearing fixing seat (5); and the servo motor (2) is used to drive the rotating shaft (31) to rotate; The clamping and centering mechanism (4) comprises two symmetrically arranged clamping arms (41), wherein a guide groove (42) opening toward the other clamping arm (41) is provided in the clamping arm (41), and a positioning block (43) and a compression spring (44) for providing elastic force to the positioning block (43) are provided in the guide groove (42), wherein the compression spring (44) and the positioning block (43) in the two clamping arms (41) are identical, and at least a portion of the positioning block (43) is located outside the guide groove (42).

2. An ultrasonic transducer assembly tool according to claim 1, characterized in that: A torque sensor (6) is installed between the torsion sleeve (32) and the torque sleeve (33).

3. An ultrasonic transducer assembly tool according to claim 1, characterized in that: A bearing (35) is provided on the rotating shaft (31), a bearing fixing seat (5) is provided on the bracket (1), and the bearing (35) is assembled in the bearing fixing seat (5); the bearing fixing seat (5) is fixed on the slide rail of the bracket (1).

4. An ultrasonic transducer assembly tool according to claim 3, characterized in that: A quick clamp (9) is also provided on the bracket (1), and the quick clamp (9) is used to drive the bearing fixing seat (5) to switch between two positions.

5. An ultrasonic transducer assembly tool according to claim 1, characterized in that: The rotating shaft (31) comprises a round shaft portion (311) and a square shaft portion (312); the servo motor (2) has a square through hole; and the square shaft portion (312) passes through the square through hole.

6. An ultrasonic transducer assembly tool according to claim 1, characterized in that: The positioning block (43) has an arc-shaped abutting surface.

7. An ultrasonic transducer assembly method, comprising: using the ultrasonic transducer assembly tool according to any one of claims 1 to 6; the ultrasonic transducer assembly tool further comprising an interconnected control system and a voltage signal acquisition and processing system, wherein the voltage signal acquisition and processing system is used to monitor the voltage at two levels of the piezoelectric ceramic stack of the transducer; The main steps include: Clamp the ultrasonic transducer between the two clamping arms (41) of the clamping and centering mechanism (4), lower the torque mechanism (3) and put the torque sleeve (33) on the bolt head of the transducer (7); A) Preliminary preloading mode: the servo motor (2) rotates at a constant speed V1 and automatically enters the preloading mode when the preset torque Q1 is detected; B) Preload mode: the servo motor (2) rotates at a speed V2 and stops when the motor reaches a preset torque Q2. At this time, the voltage between the two poles of the piezoelectric ceramic stack is U1, and the distance between U1 and the target value U is B1. When B1 is within the preset range, the next mode is entered; C) Final assembly mode: The servo motor (2) stays for a period of time T after each feed at a certain angle A, and tests the voltage signal U2 between the two poles of the piezoelectric ceramic stack. The voltage change value of the piezoelectric ceramic stack caused by the motor rotation angle A is B2, B2≤1 / 3B1, and the value of the rotation angle A decreases proportionally with the decrease of the value of U-U2. After 2 or more feeds, when the difference between U2 and U is less than the preset value, the assembly is completed.

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