A transducer

Abstract

The utility model discloses a transducer, including the back piece, rear transition sheet, transducing component, front transition sheet and amplitude changing element arranged in order from back to front, bolt passes through back piece, rear transition sheet, transducing component, front transition sheet in proper order, and with amplitude changing element screw thread connection makes the compact compaction between back piece, rear transition sheet, transducing component, front transition sheet, rear transition sheet and front transition sheet still have the positive pole wire, and the positive pole wire extends to the back, rear transition sheet and front transition sheet all are used as the refrigeration sheet, and the positive pole wire is as the positive pole of refrigeration sheet, and the negative connecting piece is as the negative pole of refrigeration sheet, and the positive electrode piece is as the positive pole of piezoelectric ceramic, and the negative connecting piece is as the negative pole of piezoelectric ceramic, the utility model has the advantages of can effectively reduce the center temperature when transducer works, reduces the acoustic system frequency drift and impedance increase due to temperature change, prolongs the life of the cutter head, does not need the time of finishing, improves the operation efficiency.

Description

Technical Field

[0001] This utility model relates to the field of medical device accessories, and in particular to a transducer with good heat dissipation. Background Technology

[0002] The transducer on a medical ultrasonic cutting hemostatic scalpel is a device that converts electrical energy into mechanical energy. Its working process can be described as follows: when current is applied to the electrode plate, the current is conducted to the piezoelectric ceramic. The piezoelectric ceramic generates high-frequency vibration under the action of the current. When the vibration is transmitted to the back block and the amplitude transformer, the amplitude transformer located at the output end amplifies the vibration and then transmits it to the titanium alloy scalpel.

[0003] Prolonged operation or excessively high temperatures can lead to increased transducer impedance, frequency drift, amplitude attenuation, and decreased performance.

[0004] Temperature changes can cause frequency drift in acoustic systems and increase impedance, which can further lead to decreased host drive efficiency, frequency loss, detuning, transducer aging, and even tool breakage.

[0005] The generation of heat during work is usually caused by the following three reasons:

[0006] (1) High-temperature sintering during the preparation of piezoelectric ceramics can lead to some defects in the material, such as pinholes, grain boundaries and cracks. These defects can form some local resistive regions, which can cause local heating when current passes through them.

[0007] (2) When piezoelectric ceramics are subjected to mechanical strain, such as strong vibration or impact, it will cause a small displacement inside the material, forming a small capacitance and resistance. These capacitances and resistances will change with the changes in external conditions, generating corresponding current and electromagnetic radiation, thereby causing the piezoelectric ceramics to heat up.

[0008] (3) Ultrasonic transducers use bolts to clamp piezoelectric ceramics between high-rigidity metal bodies such as aluminum alloy, stainless steel, or titanium alloy, firmly securing the piezoelectric ceramics and the metal body. Such transducers can generate powerful ultrasonic high-frequency vibrations. When the power supplied to the ultrasonic transducer is increased to provide high amplitude, the heat generated by the piezoelectric ceramic stack increases. Specifically, since the back block and amplitude transformer are basically made of aluminum alloy, titanium alloy, or stainless steel, there is a significant difference in acoustic impedance between them and the piezoelectric ceramics. Therefore, during the transmission of ultrasonic vibrations from the piezoelectric ceramics to the back block and amplitude transformer, some loss and reflection will occur. Furthermore, because the piezoelectric ceramics, amplitude transformer, and back block are kept in effective contact by the preload of the connecting bolts, sound wave loss and a certain degree of instability will also occur.

[0009] Therefore, given the shortcomings of existing technologies, how to effectively reduce the heat generated by ultrasonic vibration during transmission, thereby improving the stability of sound waves during transmission, has always been a problem that those skilled in the art urgently need to solve.

[0010] Existing technologies typically employ external heat dissipation components, fans, or circulating media. However, these designs increase size and weight, making them unsuitable, especially in harsh medical environments. Specifically, heat dissipation is achieved by placing heat sinks on the outer surface of the housing containing the ultrasonic transducer; alternatively, a fan is added at the rear to force air convection for cooling. However, these designs not only operate in harsh environments but also have limited heat dissipation effectiveness, making the ultrasonic transducer prone to overheating. In such cases, immediate temporary shutdown is necessary until the temperature returns to normal, resulting in prolonged overall recovery time. Utility Model Content

[0011] The purpose of this invention is to provide a transducer that can effectively reduce the center temperature of the transducer during operation, reduce frequency drift and impedance increase of the acoustic system caused by temperature changes, extend the life of the blade, eliminate the need for maintenance time, and improve surgical efficiency.

[0012] This utility model is achieved through the following technical solution: a transducer, comprising a back block 2, a rear transition plate 3, a transducer assembly 4, a front transition plate 5, and an amplitude transformer element 6 arranged sequentially from back to front; a bolt 1 passes sequentially through the back block 2, the rear transition plate 3, the transducer assembly 4, and the front transition plate 5, and is threadedly connected to the amplitude transformer element 6 to tightly compact the back block 2, the rear transition plate 3, the transducer assembly 4, and the front transition plate 5;

[0013] The transducer assembly 4 includes multiple piezoelectric ceramics 41 and multiple electrode plates. The piezoelectric ceramics 41 are arranged sequentially from front to back. Electrode plates are provided between any two adjacent piezoelectric ceramics 41, between the rear transition plate 3 and the piezoelectric ceramics 41, and between the piezoelectric ceramics 41 and the front transition plate 5. Starting from the last electrode plate, from back to front, the odd-numbered electrode plates are negative electrode plates 42, and the even-numbered electrode plates are positive electrode plates 43. Any two adjacent negative electrode plates 42 are connected by a connecting plate 44, and any two adjacent positive electrode plates 43 are connected by a connecting plate 44. The last negative electrode plate 42 is connected to a rearwardly extending negative connecting plate 45, and the last positive electrode plate 43 is connected to a rearwardly extending positive connecting plate 46.

[0014] Both the rear transition plate 3 and the front transition plate 5 are used as cooling plates; the rear transition plate 3 and the front transition plate 5 are also connected to a positive electrode line 7, which extends backward; the positive electrode line 7 serves as the positive electrode of the cooling plate, and the negative connecting plate 45 serves as the negative electrode of the cooling plate; the positive electrode plate 43 serves as the positive electrode of the piezoelectric ceramic, and the negative connecting plate 45 serves as the negative electrode of the piezoelectric ceramic.

[0015] Compared with previous technologies, the beneficial effects of this utility model are as follows:

[0016] 1. Lowering the transducer center temperature reduces acoustic system frequency drift and impedance increase caused by temperature changes, extends the life of the cutting head, reduces carbonization, effectively avoids the need for transducer downtime for maintenance, shortens surgical time, and ensures patient recovery.

[0017] 2. The addition of the transition plate ensures that the dynamic loss during transmission is reduced by about 15%-30%, thus reducing the system impedance.

[0018] 3. Improved stiffness transition and uniformity of preload distribution, resulting in enhanced mechanical quality.

[0019] 4. The addition of a transition plate can also improve the conductive path and provide effective insulation. It can be used in products that combine ultrasonic and active energy forms such as monopolar, bipolar or radio frequency to improve electrical safety. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the transducer structure of this utility model;

[0021] Figure 2 This is a schematic diagram of a traditional transducer.

[0022] Figure 3 This is a temperature status diagram of each region after the transducer of this utility model is in operation.

[0023] Figure 4 This is a temperature diagram of various regions after a traditional transducer has been put into operation.

[0024] Figure 5 Nine sampling points were taken radially from the inside out on the upper surface of the piezoelectric ceramic contact.

[0025] Figure 6 This is a diagram showing the change in contact stress between the front and rear transition plates.

[0026] Labeling explanation: 1 Bolt, 2 Back block, 3 Rear transition plate, 4 Transducer assembly, 41 Piezoelectric ceramic, 42 Negative electrode plate, 43 Positive electrode plate, 44 Connecting electrode plate, 45 Negative connecting plate, 46 Positive connecting plate, 5 Front transition plate, 6 Amplitude converter element, 7 Cooling connecting plate. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the accompanying drawings:

[0028] like Figure 1 , 2 As shown: A transducer includes a back block 2, a rear transition plate 3, a transducer assembly 4, a front transition plate 5, and an amplitude transformer 6 arranged in sequence from back to front; a bolt 1 passes through the back block 2, the rear transition plate 3, the transducer assembly 4, and the front transition plate 5 in sequence, and is threadedly connected to the amplitude transformer 6 to tightly compact the back block 2, the rear transition plate 3, the transducer assembly 4, and the front transition plate 5.

[0029] The transducer assembly 4 includes multiple piezoelectric ceramics 41 and multiple electrode plates. The piezoelectric ceramics 41 are arranged sequentially from front to back. Electrode plates are provided between any two adjacent piezoelectric ceramics 41, between the rear transition plate 3 and the piezoelectric ceramics 41, and between the piezoelectric ceramics 41 and the front transition plate 5. Starting from the last electrode plate, from back to front, the odd-numbered electrode plates are negative electrode plates 42, and the even-numbered electrode plates are positive electrode plates 43. Any two adjacent negative electrode plates 42 are connected by a connecting plate 44, and any two adjacent positive electrode plates 43 are connected by a connecting plate 44. The last negative electrode plate 42 is connected to a rearwardly extending negative connecting plate 45, and the last positive electrode plate 43 is connected to a rearwardly extending positive connecting plate 46.

[0030] Both the rear transition plate 3 and the front transition plate 5 are used as cooling plates; the rear transition plate 3 and the front transition plate 5 are also connected to a positive electrode line 7, which extends backward; the positive electrode line 7 serves as the positive electrode of the cooling plate, and the negative connecting plate 45 serves as the negative electrode of the cooling plate; the positive electrode plate 43 serves as the positive electrode of the piezoelectric ceramic, and the negative connecting plate 45 serves as the negative electrode of the piezoelectric ceramic.

[0031] from Figure 1 As can be seen, the piezoelectric ceramic stack consists of four piezoelectric ceramic ring plates, connected in series mechanically and in parallel electrically between the rear and front transition plates. The polarization directions of adjacent piezoelectric ceramic plates are opposite, allowing the longitudinal vibrations of each piezoelectric ceramic to be superimposed, ensuring coordinated vibration of the entire piezoelectric ceramic stack. To ensure that the front and rear covers are connected to electrodes of the same polarity, the number of piezoelectric ceramics is even. When an alternating electric field is applied to the piezoelectric ceramics, they undergo mechanical deformation, generating mechanical stress, i.e., a conversion between electrical energy and mechanical energy occurs. The connection methods of the piezoelectric ceramics and electrode plates are existing technologies, described in existing patents such as CN218282508U, therefore, their specific connection methods and principles will not be discussed further. The core improvement of this utility model lies in the addition of rear and front transition plates, which can effectively absorb and transfer the heat generated by the transducer.

[0032] Specifically, the rear and front transition plates of this invention are in direct contact with the heat-generating piezoelectric ceramic crystal stack of the transducer, thereby dissipating the heat generated by the operation of the piezoelectric ceramic. Furthermore, this reduces frequency drift and impedance increase in the acoustic system caused by temperature changes, effectively suppressing overheating and maintaining high processing performance without affecting power output.

[0033] It should also be noted that since the voltage on the rear transition plate 3 and the front transition plate 5 is much smaller than the voltage on the piezoelectric ceramic, specifically, the voltage on the rear transition plate 3 and the front transition plate 5 is less than 36V, which is within the safe voltage range, the rear transition plate 3 and the front transition plate 5 can still be considered as insulators.

[0034] The piezoelectric ceramics 41 are an even number, either two, four, or six. In most cases, the number of piezoelectric ceramics in this invention and existing technology is four, and the piezoelectric ceramics are in the form of a circular ring.

[0035] The elastic modulus E of the front transition plate is 5.56*10. 11 cm 3 The actual sound speed C of the finished product acl It is 3.3556 km·s -1 The target speed of sound C obtained by interpolation of the finished product tag 3.3553 km·s -1 The elastic modulus E of the rear transition plate is 13.03*10. 11 cm 3 The actual sound speed C of the finished product acl It is 5.137 km·s -1 The target speed of sound C obtained by interpolation of the finished product tag 5.138 km·s -1 .

[0036] Generally, the sound velocity of the rear and front transition plates lies between that of the piezoelectric ceramic and the metal component (back block and amplitude transformer) that provides positive pressure. This allows for the transition between sound velocities of different materials, reducing the impedance and sound reflection of the acoustic system. In practical applications, the rear and front transition plates also enable effective heat dissipation.

[0037] In the case of conventional pure ultrasonic output, the transducer's heat is efficiently dissipated and overheating is effectively suppressed by connecting the rear and front transition plates at the nodes in the transducer body where the strain and heat generation based on ultrasonic vibration are greatest. Therefore, when a large high-frequency power is supplied to the piezoelectric ceramic, the transducer can maintain high operating performance without overheating.

[0038] In the case of combined ultrasonic and bipolar output, the high-frequency ultrasonic scalpel integrates ultrasonic and high-frequency electrosurgical techniques into a single scalpel head, simultaneously outputting ultrasonic and high-frequency electrical energy. This improves tissue cutting efficiency while also satisfying coagulation requirements. Currently, a problem with bipolar ultrasonic scalpels is that bipolar energy needs to be output through a transducer. To avoid challenges to electrical safety and insulation paths, additional conductive lines are required, preventing the use of the transducer's own wiring. This limits the internal space layout of the handle housing the transducer.

[0039] It should be noted that the transducer disclosed in this utility model has applications including, but not limited to, ultrasonic cutting hemostatic knives, ultrasonic bone scalpels, cataract phacoemulsification, and piezoelectric transducers in industrial fields.

[0040] The present invention will be described below with reference to specific parameters.

[0041] The rear and front transition plates of this invention are both made of low-impedance, high-life, and highly stable materials with a density of 7.7 g / cm³ and a Poisson's ratio of 0.33. The optimal acoustic impedance parameters, calculated by interpolation based on the acoustic impedance parameters between the back block and the piezoelectric ceramic, and between the piezoelectric ceramic and the amplitude transformer element, are summarized in Table 1.

[0042] Table 1 shows the parameters of sound velocity and elastic modulus of the rear transition plate and the front transition plate.

[0043] Location <![CDATA[E / 10 11 Well]]> <![CDATA[Cacl / Km·s -1 ]]> <![CDATA[Ctag / Km·s -1 ]]> front end 5.56 3.3556 3.3553 rear end 13.03 5.137 5.138

[0044] C acl C represents the actual speed of sound of the finished product. tag The target sound velocity is obtained by interpolation; as shown in the table above, the relevant parameters of the two sets of cooling plates actually manufactured are close to the theoretical values. The manufacturing method here is as follows: by adjusting the thickness, auxiliary materials, and process parameters, two types of cooling plates with inconsistent elastic modulus E and sound velocity C are obtained.

[0045] The ideal acoustic impedance values ​​of the front and rear transition plates can be obtained by interpolation based on bolt 1, back block 2, several piezoelectric ceramics 41 and amplitude transformer 6.

[0046] In specific embodiments of this utility model, the materials and acoustic impedances of each structure are shown in Table 2:

[0047] name Material <![CDATA[Acoustic impedance Zx10 6 g / (cm 2 ·s)]]> bolt TC4Eli titanium alloy 2.83 Back block 304 stainless steel 4.46 piezoelectric ceramic assembly pzt8 piezoelectric ceramic 3.35 Amplitude Transformer Al7076 aluminum alloy 1.75

[0048] Since the front transition plate is located between the amplitude transformer 6 and the piezoelectric ceramic assembly, and the rear transition plate is located between the back block 2 and the piezoelectric ceramic assembly (ignoring the influence of the thinner negative electrode plate 45 and positive electrode plate 46), the ideal acoustic impedance values ​​of the front and rear transition plates are obtained by interpolation as 2.55 and 3.905 x 10⁶ g / (cm²), respectively. 2 ·s).

[0049] The preload of the rear transition plate and the front transition plate of this utility model is calculated using the following formula: F=μ×d×A;

[0050] Where F is the preload; μ is the coefficient of friction; d is the screw diameter; and A is the contact area.

[0051] Considering the material differences of the transition plates on both sides of the transducer assembly 4 (mainly considering the different thicknesses of the transition plates), the contact stress consistency of the ceramic plate closest to the clamping center of the transducer assembly 4 (generally the third plate from the back block towards the amplitude transformer element) is used to characterize the contact state of the acoustic system. The consistency factor = change amplitude / minimum value; the front and rear transition plates with the same acoustic impedance are in the unified group, and those with different impedances are in the variable group. Compared with the initial group of the original version, the connection direction of the four piezoelectric ceramic plates from the back block to the amplitude transformer element is represented by serial numbers 1-4 on the upper surface of the piezoelectric ceramic plates. Figure 5 The nine points represent nine sampling points along the radial direction from the inside out on the upper surface of the piezoelectric ceramic contact; Figure 6 The horizontal axis represents nine sampling points along the radial direction from the inside out on the upper surface of the piezoelectric ceramic contact; Figure 6 The solid line represents piezoelectric ceramic sheet number 1, the dashed line represents piezoelectric ceramic sheet number 2, the dotted line represents piezoelectric ceramic sheet number 3, and the double-dotted line represents piezoelectric ceramic sheet number 4; the vertical axis represents the contact stress value corresponding to the sampling point, in MPa.

[0052] The front and rear transition plates with the same acoustic impedance belong to the unified group ((2.55+3.905) / 2), while those with different impedances (2.55 and 3.905) belong to the variable group. Corresponding to the initial group of the original version, it can be seen that the normalized contact stress is consistent.

[0053] Table 3. Consistency factor table after normalization of contact stress of rear and front transition plates.

[0054]

[0055] The group with different acoustic impedance variations between the front and rear transition plates resulted in a more uniform contact stress distribution in the actual assembled product, and the measured impedance data was 15% lower than the original version, decreasing from 6.2Ω to 5.27Ω. Furthermore, the unified group demonstrates that simply installing front and rear transition plates does not achieve the desired impedance reduction; differentiated design for the front and rear transition plates is necessary to ensure that their acoustic impedance values ​​meet the requirements.

[0056] The thermal analysis of this utility model is as follows:

[0057] The total heat loss of the transducer consists of the dielectric loss and motion loss of the piezoelectric ceramic:

[0058] P total =P diel +Pmot

[0059] P diel It is a function of output power; P mot It is the power level constant corresponding to the transducer amplitude; P total是 The dielectric loss in piezoelectric ceramics is actually a function of power output.

[0060]

[0061] ω = angular frequency;

[0062] E 2 = Electric field (V / m);

[0063]

[0064] Tanδ = Dielectric loss tangent, typical value 0.002–0.01.

[0065] E (V / m) can be calculated based on the operating voltage, dynamic capacitance, and output power.

[0066]

[0067] Among them, V r,rms =Dynamic effective voltage; P out = Output power; C dyn = Dynamic capacitance; f = Resonant frequency; h = Thickness of piezoelectric ceramic.

[0068] Under stable operating conditions at full load, the following can be calculated using the above formula:

[0069] P diel =19.6W; P mot =5.4W; P total =P diel +P mot =25W;

[0070] The outer surface exchanges heat with the air; the transition plate has a volume of 259.18 mm². 3 The nominal power is 2W; the electrode plate size is small and its influence can be ignored; the above parameters are imported into the model, and the simulation results are shown in the following comparison chart. It can be seen that the introduction of the transition plate can reduce the center temperature of the heat source from the traditional 80.613℃ (see...). Figure 3 The temperature dropped to 41.837℃ (as shown). Figure 4 (As shown).

[0071] This invention can also effectively isolate the piezoelectric ceramic from the high-frequency electrical path. Since the screws, back block, and amplitude transformer that make up the transducer are all made of metal, they form an electrical short circuit with the corresponding contact surfaces of the piezoelectric ceramic. After adding the rear transition plate and the front transition plate, the direct contact between the piezoelectric ceramic and the back block and amplitude transformer is isolated, changing the overall conduction path and avoiding the influence of the bipolar circuit of the transducer on the piezoelectric ceramic.

[0072] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A transducer comprising a back block (2), a rear transition plate (3), a transducer assembly (4), a front transition plate (5), and an amplitude transformer (6) arranged sequentially from back to front; a bolt (1) passes sequentially through the back block (2), the rear transition plate (3), the transducer assembly (4), and the front transition plate (5), and is threadedly connected to the amplitude transformer (6) to tightly compact the back block (2), the rear transition plate (3), the transducer assembly (4), and the front transition plate (5); The transducer assembly (4) includes multiple piezoelectric ceramics (41) and multiple electrode plates. The piezoelectric ceramics (41) are arranged sequentially from front to back. Electrode plates are provided between any two adjacent piezoelectric ceramics (41), between the rear transition plate (3) and the piezoelectric ceramics (41), and between the piezoelectric ceramics (41) and the front transition plate (5). Starting from the last electrode plate, from back to front, the odd-numbered electrode plates are negative electrode plates (42), and the even-numbered electrode plates are positive electrode plates (43). Any two adjacent negative electrode plates (42) are connected by a connecting plate (44), and any two adjacent positive electrode plates (43) are connected by a connecting plate (44). The last negative electrode plate (42) is connected to a rearwardly extending negative connecting plate (45), and the last positive electrode plate (43) is connected to a rearwardly extending positive connecting plate (46). Both the rear transition plate (3) and the front transition plate (5) are used as cooling plates; the rear transition plate (3) and the front transition plate (5) are also connected to a positive electrode line (7), which extends backward; the positive electrode line (7) serves as the positive electrode of the cooling plate, and the negative connecting plate (45) serves as the negative electrode of the cooling plate; the positive electrode plate (43) serves as the positive electrode of the piezoelectric ceramic, and the negative connecting plate (45) serves as the negative electrode of the piezoelectric ceramic.

2. A transducer according to claim 1, characterized in that: The piezoelectric ceramics (41) are an even number, either two, four, or six.

3. A transducer according to claim 1, characterized in that: The number of the piezoelectric ceramics (41) is four.

4. A transducer according to claim 1, characterized in that: The elastic modulus E of the front transition plate (5) is 5.56*10. 11 cm 3 The actual sound speed C of the finished product acl It is 3.3556 km·s -1 The target speed of sound C obtained by interpolation of the finished product tag 3.3553 km·s -1 The elastic modulus E of the rear transition plate is 13.03*10. 11 cm 3 The actual sound speed C of the finished product acl It is 5.137 km·s -1 The target speed of sound C obtained by interpolation of the finished product tag 5.138 km·s -1 .

Images