Catenary low amplitude ultrasonic welding die

Abstract

The application discloses a catenary type low-amplitude ultrasonic welding die, belongs to the technical field of low-amplitude ultrasonic welding die equipment, and is used for welding a grid-containing PCV valve. The catenary type low-amplitude ultrasonic welding die comprises a welding upper die and a welding lower die. The welding upper die is composed of an upper segment and a lower segment. The mounting end of the upper segment is connected with a transducer through an amplitude adjuster. The lower segment is composed of a catenary structure and a welding segment. The welding segment is provided with an air outlet cavity at the bottom end, which is suitable for accommodating the upper shell of the PCV valve, so that the end face of the welding segment is opposite to the welding position between the upper shell and the lower shell of the PCV valve. The bottom of the welding segment is coaxially provided with a horn structure. In the case that the length ratio between the lower segment and the catenary structure is fixed, the gain ratio of the welding upper die is 1.45-1.88. The welding die provided by the application can greatly reduce or even completely eliminate the cracking of the grid and effectively avoid the problems that the throttle plate is shaken and lifted or separated.

Description

Technical Field

[0001] This invention relates to the field of low-amplitude ultrasonic welding mold equipment technology, and more particularly to a catenary-type low-amplitude ultrasonic welding mold. Background Technology

[0002] A transducer, or ultrasonic transducer, is a device that converts input electrical power into mechanical power (i.e., ultrasonic waves) and then transmits it out, while consuming very little power itself. Generally, there are magnetostrictive and piezoelectric ceramic types.

[0003] An amplitude modulator, or ultrasonic amplitude modulator, is a device that can change the amplitude of ultrasonic waves.

[0004] Currently, there exists a PCV valve device containing a grille, diaphragm, and throttle plate. The PCV valve (Positive Crankcase Ventilation Valve) primarily utilizes the pressure difference between the crankcase and the intake manifold to guide blow-by gases from the crankcase through the PCV valve and connecting hoses into the intake manifold, and then into the combustion chamber for combustion. PCV valves are mainly divided into plunger type and diaphragm type. The diaphragm type, also known as a one-way valve, mainly consists of an upper housing, a lower housing, a diaphragm, and a throttle plate. During operation, the one-way valve senses the pressure difference across its sides, causing the airflow to open the diaphragm. The airflow rate is controlled by the angle of the diaphragm's opening.

[0005] Ultrasonic welding is a welding method that converts electrical energy into mechanical energy, and then into internal energy (thermal energy). Essentially, it welds parts together by generating heat through friction. The upper welding mold is usually a composite or stepped structure. The upper welding mold emits ultrasonic waves, which are transmitted through the contact surface to the weld line to melt it. The lower welding mold provides effective support for the product.

[0006] In recent years, with the increase in the size of PCV valves, welding problems have also been increasing, especially for diaphragm check valves. Because of the presence of grids of different sizes and shapes inside, ultrasonic welding can easily cause microcracks of varying degrees or even breakage due to stress concentration. At the same time, excessive energy overflow can also cause the throttle plate to warp due to vibration, ultimately causing the reverse shut-off function of the check valve to fail.

[0007] Currently, some manufacturers may try to improve the problem of grid breakage by shortening the support distance or reducing the weld line size, but this will lead to problems such as reduced welding strength and weld damage on the product surface. Some manufacturers have also tried to optimize the product structure, such as thickening the grid or increasing the radius, but this still cannot eliminate the cracking problem.

[0008] To address the issue of the throttle plate warping, the usual method is to increase the welding parameters, but this can easily cause further damage to the components. Summary of the Invention

[0009] One advantage of this invention is that it provides a catenary-shaped low-amplitude ultrasonic welding mold, wherein the upper welding mold is designed with a catenary shape, and the welding end face of the welding section of the upper welding mold is designed with a flared mouth to obtain a mold gain ratio that is much lower than the industry norm. Under low amplitude conditions, it can greatly reduce or even completely eliminate the occurrence of cracks in the grid and effectively avoid the problem of the throttling plate being vibrated and lifted or falling off.

[0010] To achieve at least one of the advantages of this invention, the present invention provides a catenary-type low-amplitude ultrasonic welding mold for low-amplitude ultrasonic welding of a PCV valve containing a grid. The welding mold includes a cooperating upper welding mold and a lower welding mold. The upper welding mold is composed of an upper section and a lower section along its length. The mounting end of the upper section is connected to a transducer via an amplitude modulator. The lower section consists of a catenary structure and a welding section. The catenary structure is located close to the upper section. The welding section has an outlet chamber at its bottom suitable for accommodating the upper housing of the PCV valve, such that the end face of the welding section faces the welding position between the upper housing and the lower housing of the PCV valve. A flared structure is coaxially provided at the bottom of the welding section, protruding radially from the welding section. With a fixed length ratio between the lower section and the catenary structure, the gain ratio of the upper welding mold is 1.45 to 1.88, i.e., the mass ratio between the upper and lower sections is 1.45 to 1.88.

[0011] According to one embodiment of the present invention, the ratio between the length of the welding upper mold and the length of the catenary structure is 2.6 to 3.6, and the ratio between the edge length of the axial section of the catenary structure and the length of the catenary structure is 1.01 to 1.04.

[0012] According to one embodiment of the present invention, the ultrasonic amplitude output from the end face of the welding segment is 58µm to 75µm.

[0013] According to one embodiment of the present invention, the ratio of the outer diameter of the flared structure to the outer diameter of the welded section is 1.05 to 1.15.

[0014] According to one embodiment of the present invention, the gain ratio is 1.45, and the ratio of the outer diameter of the flared structure to the outer diameter of the welded section is 1.05.

[0015] According to one embodiment of the present invention, the gain ratio is 1.55, and the ratio of the outer diameter of the flared structure to the outer diameter of the welded section is 1.1.

[0016] According to one embodiment of the present invention, the gain ratio is 1.65, and the ratio of the outer diameter of the flared structure to the outer diameter of the welded section is 1.1.

[0017] According to one embodiment of the present invention, the gain ratio is 1.75, and the ratio of the outer diameter of the flared structure to the outer diameter of the welded section is 1.15.

[0018] According to one embodiment of the present invention, the gain ratio is 1.88, and the ratio of the outer diameter of the flared structure to the outer diameter of the welded section is 1.15.

[0019] These and other objects, features and advantages of the present invention will become fully apparent from the following detailed description. Attached Figure Description

[0020] Figure 1 A cross-sectional structural schematic diagram of a preferred embodiment of the present application of a catenary-type low-amplitude ultrasonic welding mold is shown.

[0021] Figure 2 A three-dimensional structural schematic diagram of the welding upper mold in this application is shown. Detailed Implementation

[0022] The following description is intended to disclose the present invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the invention.

[0023] Those skilled in the art should understand that, in the disclosure of this specification, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the above terms should not be construed as limiting the present invention.

[0024] It is understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element can be one, while in another embodiment, the number of the element can be multiple, and the term "a" should not be understood as a limitation on the number.

[0025] A catenary is a curve formed by a uniformly shaped, flexible (inextensible) chain fixed at both ends under the influence of gravity. Examples include suspension bridges. It is named for its resemblance to a rope fixed at both ends drooping under uniform gravitational force. With a suitable coordinate system, the equation of a catenary is a hyperbolic cosine function, with the standard equation: y = a cosh(x / a), where a is the distance from the vertex of the curve to the horizontal axis.

[0026] Gain ratio is the amplification ratio of the received amplitude by the mold. It is usually the ratio of the volume of the upper end of the mold to the volume of the lower end, or the ratio of the mass of the upper end to the mass of the lower end.

[0027] Due to the special structure of the PCV valve with grille, the grille is subjected to stress concentration due to the ultrasonic waves during ultrasonic welding, which makes it very easy to crack and break. At the same time, due to the vibration of the ultrasonic waves and the leakage of some energy, the throttling plate can also be easily caused to tilt or even fall off in one direction during welding, resulting in excessive reverse leakage of the PCV valve and failure of the reverse shut-off function.

[0028] Therefore, how to avoid the grid being broken or the throttle plate being dislodged during ultrasonic welding is one of the urgent problems to be solved.

[0029] refer to Figure 1 and Figure 2A preferred embodiment of the present invention, a catenary-type low-amplitude ultrasonic welding mold, will be described in detail below. This catenary-type low-amplitude ultrasonic welding mold is used for low-amplitude ultrasonic welding of a PCV valve containing a grid. The welding mold includes a cooperating upper welding mold 10 and a lower welding mold 20. The upper welding mold 10 is composed of an upper section 11 and a lower section 12 along its length. The mounting end 111 of the upper section 11 is connected to a transducer via an amplitude modulator. The transducer generates ultrasonic waves, which are amplified by the amplitude modulator and then amplified again by the upper welding mold 10 before being output to the upper housing 31 of the PCV valve 30. This causes the upper housing 31 to vibrate at high frequency, while the lower housing 32 of the PCV valve 30 remains relatively stationary. Frictional heat is generated between the upper housing 31 and the lower housing 32, melting the weld wire and ultimately welding the upper housing 31 and the lower housing 32 together. The resulting one-way valve has both forward conduction and reverse shut-off functions, and its reverse sealing performance is reliable. Furthermore, the lower section 12 is composed of a catenary structure 121 and a welding section 122. The catenary structure 121 is close to the upper section, and the welding section 122 has an exhaust chamber 101 at its bottom end suitable for accommodating the upper housing 31 of the PCV valve 30. This ensures that the end face 124 (i.e., the welding wave-generating surface) of the welding section 122 is directly opposite the welding position between the upper housing 31 and the lower housing 32 of the PCV valve 30. In addition, a flared structure 123 is coaxially provided at the bottom of the welding section 122. The flared structure 123 protrudes radially from the welding section 122, thereby avoiding excessive concentration of ultrasonic waves. Moreover, when the length ratio L1 / L2 between the lower section 12 (L1) and the catenary structure 121 (L2) is fixed, the gain ratio of the welding upper mold 10 is 1.45 to 1.88, that is, the mass ratio between the upper section 11 and the lower section 12 is 1.45 to 1.88.

[0030] For the debugging and verification of the upper welding mold 10 and the lower welding mold 20, a 20kHz ultrasonic device was used, set to energy mode or time mode. At the same time, a common piezoelectric ceramic transducer was used, and a 1:2 composite amplitude modulator was selected. The transducer, amplitude modulator and the upper welding mold 10 were connected in sequence to form a three-unit group, which was installed on the ultrasonic welding machine and tightened. At the same time, the lower welding mold 20 was made concentric with the upper welding mold 10 by using alignment fixtures and tightened. The mold verification was performed by pressing the "TEST" button of the ultrasonic welding machine. The mold no-load power was between 56 and 66W and the vibration frequency was between 19989 and 19996. The mold verification was completed.

[0031] For the verification of welding process parameters, an ultra-low amplitude catenary mold, namely the upper welding mold 10, was used. Simultaneously, the transducer parameters were adjusted accordingly. The catenary low-amplitude ultrasonic welding mold provided in this application was used as the experimental group, while the composite mold and stepped mold were used as control group I and control group II, respectively. DOE tests were conducted, and the test data are shown in the table below:

[0032]

[0033] The airtightness in the table refers to the airtightness of the weld joint under the condition of <0.35ml / min;

[0034] The heights in the table are the benchmark welding depths under conditions of <8.65mm;

[0035] The strengths in the table are benchmark melting conditions under >800N conditions;

[0036] The above three are all indicators for verifying welding quality, and are average values ​​obtained after extensive experimental verification.

[0037] As can be seen from the table above, the catenary-type low-amplitude ultrasonic welding mold provided in this application can greatly reduce or even completely eliminate the occurrence of cracks during the welding process. At the same time, the proportion of throttle plates being dislodged by vibration is 0, thus effectively solving the problems of grid breakage and throttle plate warping or dislodging during the ultrasonic welding of PCV valve 30 containing grid.

[0038] In one embodiment, the ratio between the length L of the upper welding mold 10 and the length L2 of the catenary structure 121 is 2.6 to 3.6, that is, the ratio between the length L of the upper welding mold 10 and the length L2 of the catenary structure 121 can be any value within the range of 2.6 to 3.6, rounded to one decimal place, such as 2.7, 2.8, 3.1, 3.3 or 3.5. Meanwhile, the ratio between the edge length L3 of the axial section of the catenary structure 121 and the length L2 of the catenary structure is 1.01 to 1.04, such as 1.02 or 1.03.

[0039] In one embodiment, the ultrasonic amplitude output by the end face 124 (i.e. the wave-emitting surface of the mold) of the welding section 122 is 58um to 75um, such as 59um, 60um, 74um, etc., and can be any integer value in the range of 58um to 75um, which will not be elaborated here.

[0040] In one embodiment, the ratio of the outer diameter of the flared structure 123 to the outer diameter of the welded segment is 1.05 to 1.15. That is, the ratio of the outer diameter of the flared structure 123 to the outer diameter of the welded segment can be any value with two decimal places in the range of 1.05 to 1.15, such as 1.06, 1.08, 1.12, 1.13 or 1.14.

[0041] In one embodiment, the gain ratio is 1.45, and the ratio of the outer diameter of the horn structure 123 to the welded section 122 is 1.05.

[0042] In one embodiment, the gain ratio is 1.55, and the ratio of the outer diameter of the horn structure 123 to the welded section 122 is 1.1.

[0043] In one embodiment, the gain ratio is 1.65, and the ratio of the outer diameter of the horn structure 123 to the welded section 122 is 1.1.

[0044] In one embodiment, the gain ratio is 1.75, and the ratio of the outer diameter between the flared structure 123 and the welded section 122 is 1.15.

[0045] In one embodiment, the gain ratio is 1.88, and the ratio of the outer diameter of the horn structure 123 to the welded section 122 is 1.15.

[0046] Those skilled in the art should understand that the embodiments of the present invention described above and shown in the accompanying drawings are merely examples and do not limit the invention. The advantages of the present invention have been fully and effectively realized. The functional and structural principles of the present invention have been demonstrated and explained in the embodiments; any variations or modifications can be made to the implementation of the present invention without departing from these principles.

Claims

1. A catenary-type low-amplitude ultrasonic welding mold for low-amplitude ultrasonic welding of a PCV valve containing a grid, wherein the welding mold comprises a mating upper welding mold and a lower welding mold, characterized in that, The welding upper mold is composed of an upper section and a lower section along its length. The mounting end of the upper section is connected to a transducer via an amplitude modulator. The lower section is composed of a catenary structure and a welding section. The catenary structure is close to the upper section. The welding section has an exhaust chamber at its bottom end suitable for accommodating the upper housing of the PCV valve, such that the end face of the welding section is directly opposite the welding position between the upper housing and the lower housing of the PCV valve. The bottom of the welding section is coaxially provided with a flared structure that protrudes radially from the welding section. With a fixed length ratio between the lower section and the catenary structure, the gain ratio of the welding upper mold is 1.45 to 1.88, that is, the mass ratio between the upper section and the lower section is 1.45 to 1.

88. The ratio of the outer diameter of the flared structure to the outer diameter of the welded section is 1.05 to 1.

15.

2. The catenary-type low-amplitude ultrasonic welding mold as described in claim 1, characterized in that, The ratio between the length of the welding upper mold and the length of the catenary structure is 2.6 to 3.6, and the ratio between the edge length of the axial section of the catenary structure and the length of the catenary structure is 1.01 to 1.

04.

3. The catenary-type low-amplitude ultrasonic welding mold as described in claim 1, characterized in that, The ultrasonic amplitude output from the end face of the welding section is 58µm to 75µm.

4. The catenary-type low-amplitude ultrasonic welding mold as described in claim 1, characterized in that, The gain ratio is 1.45, and the ratio of the outer diameter of the flared structure to the outer diameter of the welded section is 1.

05.

5. The catenary-type low-amplitude ultrasonic welding mold as described in claim 1, characterized in that, The gain ratio is 1.55, and the ratio of the outer diameter of the flared structure to the outer diameter of the welded section is 1.

1.

6. The catenary-type low-amplitude ultrasonic welding mold as described in claim 1, characterized in that, The gain ratio is 1.65, and the ratio of the outer diameter of the flared structure to the outer diameter of the welded section is 1.

1.

7. The catenary-type low-amplitude ultrasonic welding mold as described in claim 1, characterized in that, The gain ratio is 1.75, and the ratio of the outer diameter of the flared structure to the outer diameter of the welded section is 1.

15.

8. The catenary-type low-amplitude ultrasonic welding mold as described in claim 1, characterized in that, The gain ratio is 1.88, and the ratio of the outer diameter of the flared structure to the outer diameter of the welded section is 1.15.

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