JP2010149424A - Vibration welding method and vibration welding apparatus used for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration welding method capable of suppressing the amount of wearing powder generated before abutting faces melt as much as possible when rubbing resin members themselves and a vibration welding apparatus used for the same. <P>SOLUTION: In the vibration welding method in which the abutting faces are melted by generating friction heat by vibration in the two abutting faces by abutting the two resin parts while compressing the same to weld two resin parts, the amplitude of the vibration A is varied, the amplitude is held in a predetermined value (the first threshold value A1) or less in at least the period from T0 when starting vibration to T1 when melting of the abutting faces starts, thereafter the amplitude A is raised to the larger value (the second threshold value A2) than the predetermined value A1 after the abutting faces start to melt. The compression force F is varied according to the predetermined correlation with the amplitude A. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vibration welding method and a vibration welding apparatus used therefor, and more particularly to a vibration welding method and a vibration welding apparatus that suppress the generation of wear powder during friction.

Conventionally, a vibration welding method is known as a method of welding resin parts. In this vibration welding method, two resin parts are brought into contact with each other while being pressed, and the contact surfaces are vibrated. Then, the contact surface is melted using the frictional heat generated here. When the contact surface melts, the vibration is stopped, and the contact surface is cooled and solidified to join the components.
Here, the pressing force for pressurizing the resin parts to each other by the vibration welding method needs to be equal to or greater than a predetermined magnitude, but various control methods for the pressing force have been developed to increase the bonding strength (for example, patents) References 1 and 2). In these methods, as in the conventional method, after suddenly pressurizing with a large force once, control is performed to slow down the increasing rate of pressurization or lower the applied pressure.

  However, in the vibration welding method described above, since the pressure is rapidly increased with a large force before melting and the amplitude is large, a large amount of separation burrs, that is, wear powder, is generated due to friction between members before welding. When the parts to be welded are parts that require high cleanliness, such as filter members and seal members, for example, if the parts are contaminated by the generated wear powder, it is necessary to clean them after welding. .

JP 2002-301768 A Japanese Patent Laid-Open No. 10-264255

  The present invention has been made in view of the above-described situation, and a vibration welding method capable of suppressing the amount of wear powder generated before the contact surface melts when the resin parts are frictioned with each other and the vibration welding method used therein. An object is to provide a vibration welding apparatus.

The present invention is as follows.
1. In a vibration welding method in which two resin parts are brought into contact with pressure, frictional heat due to vibration is generated on the contact surface to melt the corresponding contact surface, and the two resin parts are welded.
The amplitude of the vibration is varied, and the amplitude is maintained at a predetermined value or less during at least a period from the start of vibration to the start of melting of the contact surface, and then the amplitude is set to the predetermined value after the start of melting of the contact surface. The vibration welding method is characterized in that it is increased to a value larger than that.
2. The amplitude reaches the predetermined value before the start of melting of the contact surface. The vibration welding method described.
3. The amplitude continues to increase at a predetermined rising gradient at least during a period from the start of vibration to the start of melting of the contact surface. The vibration welding method described.
4). 2. The amplitude increases to a value larger than the predetermined value with an ascending gradient larger than the predetermined ascending gradient after the contact surface starts melting. The vibration welding method described.
5). The pressure is variable with a predetermined correlation with the amplitude. To 4. The vibration welding method according to any one of the above.
6). Above 1. To 5. A vibration welding apparatus used in the vibration welding method according to any one of
A vibration source provided with a variable amplitude;
A vibration plate that is vibrated by being vibrated by the vibration source;
A stationary plate provided to face the vibration plate and displaceable in a direction to face the vibration plate;
A displacement mechanism for displacing the stationary plate in a direction facing the vibration plate;
A vibration-side jig fixedly attached to the vibration plate so as to hold one resin part of the two resin parts and vibrate with the vibration plate;
A stationary jig that holds the other resin component of the two resin components and is fixedly attached to the stationary plate;
A vibration welding apparatus comprising: a control means for controlling the vibration source and the displacement mechanism.
7). 5. The electromagnetic vibration generator according to the above 6, wherein the vibration source includes an electromagnetic coil and an inverter that varies the amplitude by varying a high-frequency current applied to the electromagnetic coil. The vibration welding apparatus as described.
8). 5. The displacement mechanism includes a ball screw and a servo motor that drives the ball screw and varies the driving torque of the driving to vary the applied pressure. Or 7. The vibration welding apparatus as described.

According to the vibration welding method of the present invention, the amplitude is maintained at a predetermined value or less during at least the period from the start of vibration to the start of melting of the contact surface, and then the value greater than the predetermined value after the start of melting of the contact surface. Therefore, the friction range between the resin parts before melting is reduced, and the generation of wear powder can be suppressed. Thereby, even when the parts to be welded are parts that require high cleanliness, such as filter members and seal members, it is possible to prevent the necessity of cleaning after welding due to generation of wear powder as much as possible. .
Further, when the amplitude reaches the predetermined value before the start of melting of the contact surface, the amplitude can be quickly increased to the predetermined value, so that the time until the contact surface starts to melt As well as the generation of wear powder.
Further, when the amplitude continues to increase at a predetermined rising gradient at least from the start of vibration to the start of melting of the contact surface, the amplitude is gradually increased from the start of vibration to the start of melting. Can do. Therefore, the impact on the resin part due to vibration can be suppressed.
In addition, when the amplitude increases after the start of melting of the contact surface to a value greater than the predetermined value with an upward gradient greater than the predetermined upward gradient, the amplitude is gradually increased from the start of vibration to the start of melting. And can be quickly raised to the upper limit after the start of melting. Thereby, the time of the whole welding process can be shortened, suppressing the impact to the resin component by vibration.
Moreover, when the said applied pressure changes with the said amplitude with a predetermined | prescribed correlation, it can be set as the optimal applied pressure matched with the variable of an amplitude, and generation | occurrence | production of abrasion powder can be suppressed more.
On the other hand, according to the vibration welding apparatus of the present invention, vibration at the time of welding can be applied by a vibration source provided with variable amplitude, so that the amplitude can be arbitrarily controlled. Accordingly, as described above, the amplitude of the contact surface until the melting starts can be reduced, and the amplitude can be increased and increased to the upper limit value after the melting starts. Thereby, it is possible to reduce the friction range between the resin parts before melting and suppress the generation of wear powder.
When the vibration source is an electromagnetic vibration generator having an electromagnetic coil and an inverter that varies the amplitude by varying a high-frequency current applied to the electromagnetic coil, The amplitude at the time of welding can be easily varied.
Further, when the displacement mechanism includes a ball screw and a servo motor that drives the ball screw and varies the driving torque of the driving to vary the applied pressure, the driving torque can be easily varied. The pressurizing force at the time of welding can be easily varied by the servo motor.

  In the vibration welding method according to this embodiment, two resin parts are brought into contact with each other while being pressed, frictional heat due to vibration is generated on the contact surface to melt the corresponding contact surface, and the two resin parts are welded and vibration-bonded. In the welding method, the amplitude of the vibration is varied, and the amplitude is maintained at a predetermined value or less during at least a period from the start of vibration to the start of melting of the contact surface, and then the amplitude after the start of melting of the contact surface. Is increased to a value larger than the predetermined value.

  The material for the “resin component” is not particularly limited. For example, it can be a synthetic resin such as plastic, and specifically, a synthetic resin such as polyamide 6 or polypropylene, or a material mainly composed thereof. be able to.

  As long as the “vibration” generates frictional heat on the contact surface, its vibration frequency, vibration form, etc. are not particularly limited. As said vibration frequency, it can be 200-300 Hz (preferably 210-240 Hz), for example. Examples of the vibration form include a form that vibrates by reciprocating linear motion on a plane, a form that vibrates by moving in a circular arc on a plane, and the like.

  The “amplitude” is maintained at a predetermined value or less during at least a period from the start of vibration to the start of melting of the contact surface, and then increases to a value greater than the predetermined value after the start of melting of the contact surface. The variable form is not particularly limited. For example, (1) a mode in which the predetermined value is reached before the start of melting of the contact surface (for example, see FIG. 3), and (2) at least the start of the vibration from the start of the vibration. The period until the start of melting continues to rise at a predetermined rising gradient (see, for example, FIG. 4), (3) At least the period from the start of vibration to the start of melting of the contact surface increases at a predetermined rising gradient Subsequently, after the start of melting of the contact surface, there can be exemplified a form (for example, see FIG. 5 and the like) that rises to a value larger than the predetermined value with an upward gradient larger than the predetermined upward gradient.

In the case of (1), it is preferable that the time until the amplitude reaches the predetermined value is as fast as possible from the viewpoint of reducing the time until the contact surface is melted. That is, it is preferable that the rising gradient until reaching the predetermined value is as large as possible. Further, from the viewpoint of alleviating the impact on the resin component, it is preferable that the time until the amplitude reaches the predetermined value is as late as possible. That is, it is preferable that the rising gradient until reaching the predetermined value is as small as possible. For the sake of safety, the amplitude after the start of melting can be maintained at a value equal to or less than a predetermined value for a certain period of time.
In the cases (2) and (3), the predetermined ascending gradient is set to reach a predetermined value after a predetermined time has elapsed from the start of melting, or set to reach a predetermined value at the start of melting. Also good.

  The “predetermined value” is not particularly limited in size as long as the frictional range caused by vibration is reduced so that abrasion powder is not generated as much as possible. The size of the predetermined value can be appropriately set in consideration of the material properties such as the melting start temperature and heat capacity of the resin parts to be welded, the contact area between the resin parts, etc. The upper limit value is preferably 20 to 50 percent, more preferably 30 to 40 percent. Specifically, when the upper limit value of the amplitude is, for example, 1.5 to 2.4 mm, it can be 0.3 to 1.2 mm.

Here, in the vibration welding method according to the present embodiment, the applied pressure can be varied with a predetermined correlation with the amplitude (see, for example, FIG. 2). This is because it is possible to obtain an optimum pressure applied in accordance with the variable amplitude, and to reduce the frictional force applied to the contact surface before melting, thereby further suppressing the generation of wear powder.
The “predetermined correlation” can be appropriately set in consideration of the material properties such as the melting start temperature and heat capacity of the resin parts to be welded, the contact area between the resin parts, and the like. It can be 1.4 tons when 5 mm, and 2.0 tons when the amplitude is 1.8 mm.

  On the other hand, a vibration welding apparatus according to the present invention includes a vibration source provided with a variable amplitude, a vibration plate that is vibrated by being vibrated by the vibration source, a vibration plate provided so as to face the vibration plate, and A stationary plate that is displaceable in the opposite direction, a displacement mechanism that displaces the stationary plate in a direction opposite to the vibration plate, and vibrates so as to hold one of the two resin parts and vibrate with the vibration plate. A vibration side jig fixedly attached to the plate, a stationary side jig that holds the other resin part of the two resin parts and is fixedly attached to the stationary plate; Control means for controlling the vibration source and the displacement mechanism.

  The “vibration source” generates vibrations for generating frictional heat due to vibrations on the contact surfaces between the resin parts. As long as the vibration amplitude is variable, the structure, vibration The generation form is not particularly limited. Examples of the vibration source include an electromagnetic vibration generator having an electromagnetic coil, a vibration motor, and an ultrasonic vibration generator. Moreover, as a form which varies amplitude, the form etc. which vary the high frequency current applied by an inverter can be mentioned.

The “vibration plate” is not particularly limited in its structure, material, vibration form and the like as long as it is vibrated by the vibration source. Examples of the vibration form of the vibration plate include a form that vibrates by reciprocating linear motion on a plane, a form that vibrates by moving in a circular arc on a plane, and the like.
As long as the “stationary plate” is provided so as to face the vibration plate and can be displaced in a direction facing the vibration plate, the structure, material, displacement form and the like are not particularly limited.
As long as the “displacement mechanism” displaces the stationary plate in a direction facing the vibration plate, the structure, the drive form, and the like are not particularly limited. As the displacement mechanism, for example, a mechanism using a ball screw and a servo motor, a hydraulic cylinder, an air cylinder, and the like, which can displace the stationary plate by a slide member such as a slide unit or a ball spline, can be cited.

As long as the “vibration side jig” is fixedly attached to the vibration plate so as to hold one resin part of the two resin parts and vibrate together with the vibration plate, its structure The shape, material, etc. are not particularly limited. Examples of the material of the vibration side jig include metal materials such as steel and aluminum alloy, resin materials, ceramics, and the like. From the viewpoint of weight reduction and strength of the jig, the material of the vibration side jig is preferably an aluminum alloy.
As long as the above-mentioned “stationary side jig” holds the other resin part of the two resin parts and is fixedly attached to the stationary plate, its structure, shape, material, and attachment form Etc. are not particularly limited. As an attachment form of the stationary side jig, for example, it may be an attachment form using a known means such as a fixing means having a link mechanism such as a hydraulic clamp. Moreover, it is good also as an attachment form similar to the form which attaches the said vibration side jig | tool to the said vibration plate.
As long as the “control means” controls the vibration source and the displacement mechanism, the shape, form, number, etc. thereof are not particularly limited. The control means can individually control the vibration source and the displacement mechanism, or can perform the other control in association with one control.

  Hereinafter, the present invention will be specifically described with reference to the drawings.

(1) Configuration of Vibration Welding Apparatus The vibration welding apparatus 1 according to the present embodiment is generated by abutting while pressing the upper member 2 and the lower member 3 that are two resin parts, and vibrating the abutting surfaces. The vibration welding method is used in which the contact surfaces are melted by using the frictional heat to weld the members 2 and 3 together. As shown in FIG. 1, the vibration welding apparatus 1 includes a vibration source 11 that generates vibration for welding, and an upper platen 12 that is vibrated by the vibration source 11 (the vibration plate according to the present invention). And a lower platen 13 (exemplified as a stationary plate according to the present invention) provided so as to face the lower side of the upper platen 12, and an elevating mechanism 14 for moving up and down the lower platen 13 (present invention). And a welding upper jig 15 fixedly attached to the upper platen 12 so as to vibrate together with the upper platen 12 (illustrated as a vibration side jig according to the present invention). ), A welding lower jig 16 fixedly attached to the lower platen 13 (illustrated as a stationary jig according to the present invention), a control for controlling the vibration source 11 and the lifting mechanism 14. Part 17 and (exemplified as a control means according to the present invention), and a.
The upper member 2 and the lower member 3 are made of polyamide 6 and have a frame shape. The upper member 2 and the lower member 3 are held so as to face and abut the upper platen 12 and the lower platen 13, respectively.

  The vibration source 11 includes an electromagnetic coil 11a, an inverter 11b, a suction member 11c, and a leaf spring 11d. Two electromagnetic coils 11a are provided at both ends in the direction of vibration (the left-right direction in FIG. 1), respectively, and are applied with variable high-frequency currents contradicting each other from the inverter 11b, and can generate magnetic force at an arbitrary period. The attracting member 11c is disposed at a position facing each electromagnetic coil 11a on the upper platen 12 side, receives the magnetic force generated by the electromagnetic coil 11a, and approaches and separates from the electromagnetic coil 11a. The upper end side of the leaf spring 11d is fixed to the top plate 18 of the vibration welding apparatus 1, and the upper platen 12 is attached to the lower end side thereof.

As described above, the upper platen 12 is supported by the top plate 18 through the leaf spring 11d so as to vibrate left and right, and the attracting members 11c are alternately attracted and vibrated by energizing the electromagnetic coil 11a. And when the high frequency current controlled by the inverter 11b is energized to the electromagnetic coil 11a, the amplitude of the vibration can be arbitrarily changed.
A welding upper jig 15 is detachably attached to the bottom surface side of the upper platen 12. The welding upper jig 15 has an outer shape on the upper surface side of the upper member 2 so that the upper member 2 which is one of the two resin components bonded by vibration welding can be held on the lower surface side thereof. A corresponding concave holding portion 15a is provided.

The lifting mechanism 14 includes a ball screw 14a, a servo motor 14b, and a lifting table 14c. A lower platen 13 is placed on the lifting table 14c, and a welding lower jig 16 is detachably attached to the upper surface side of the lower platen 13. The welding lower jig 16 is provided on the upper surface side of the lower member 3 so as to hold the lower member 3 which is one of the two resin components joined by vibration welding. It has a concave holding portion 16a corresponding to the outer shape.
The upper end side of the ball screw 14a is attached to the lifting table 14c. Then, when the servo motor 14b drives the ball screw 14a, the lifting table 14c is moved up and down. Further, the servo motor 14b can vary its driving torque, so that when the upper member 2 and the lower member 3 are brought into contact with each other by being lifted and lowered by the lifting table 14c, the contact surface thereof. The pressurizing force applied to can be arbitrarily varied.

  The control unit 17 controls the inverter 11b and the servo motor 14b so as to vary the amplitude and the applied pressure during welding according to the correlation shown in FIG.

(2) Vibration Welding Method Next, a vibration welding method using the vibration welding apparatus having the above configuration will be described.
First, the upper member 2 is fixed to the holding portion 15 a of the welding upper jig 15, and the lower member 3 is fixed to the holding portion 16 a of the welding lower jig 16. Then, the lower platen 13, the welding lower jig 16 and the lower member 3 are raised by the lifting mechanism 14. Thereby, the upper member 2 and the lower member 3 contact | abut.

  Next, as shown in FIG. 3, the controller 17 controls the servo motor 14b of the elevating mechanism 14 to increase the pressure on the contact surface to the initial pressure F0. Then, in this pressurized state, the control unit 17 controls the inverter 11b of the vibration source 11 to start vibration of the upper platen 12, the welding upper jig 15, and the upper member 2 at a predetermined frequency.

  Thereafter, as shown in FIG. 3, the control unit 17 controls the inverter 11b to increase the amplitude to the first predetermined value A1 with a predetermined rising gradient. The first predetermined value A1 can reduce the generation of abrasion powder by reducing the friction range when the contact surfaces of the members 2 and 3 are rubbed in an unmelted state, and until the melting starts. This time is set as a value that can be made relatively short. Moreover, the control part 17 controls the servomotor 14b based on the conditions of the relationship between the applied pressure and amplitude shown in FIG. 2, and raises an applied pressure. That is, until the amplitude value increases and reaches A1, the pressure value also increases according to the above condition and reaches F1. Then, the amplitude and the applied pressure are changed with the magnitudes of A1 and F1 until time T1 when the contact surfaces of the members 2 and 3 start to melt.

  As described above, the amplitude and the applied pressure are changed while maintaining the magnitudes of A1 and F1, respectively. When the contact surfaces of the members 2 and 3 reach the time T1 at which the melting starts, the amplitude is set to the amplitude of the vibration welding. The inverter 11b is controlled to increase to the second predetermined value A2 that is the upper limit value, and the servo motor 14b is controlled to increase the applied pressure accordingly.

In this state, the vibration and pressurization are continued to sufficiently melt the contact surface, and when the predetermined time T2 is reached, the vibration is stopped. Then, the contact surface between the upper member 2 and the lower member 3 in a molten state is solidified again, and the upper member 2 and the lower member 3 are joined.
Finally, the welding lower jig 16 is lowered, and the upper member 2 and the lower member 3 which are joined and integrated are removed from the jig.

(3) Effects of the Example According to the vibration welding apparatus 1 of this embodiment and the vibration welding method using the vibration welding apparatus 1, the period from the start of vibration to the start of melting of the upper member 2, the lower member 3, and the contact surface has an amplitude. Since the amplitude is increased to the second predetermined value A2 after the first predetermined value A1 is maintained and then the melting of the contact surface is started, the friction range between the resin parts before melting can be reduced. And generation of wear powder can be suppressed. Thereby, even when the parts to be welded are parts that require high cleanliness, such as filter members and seal members, it is possible to prevent the necessity of cleaning after welding due to generation of wear powder as much as possible. . Further, during this time, the pressing force is optimally varied with a predetermined correlation with the amplitude. Therefore, the frictional force of the contact surface can be optimized to further suppress the generation of wear powder.
Further, since the amplitude is rapidly increased to the first predetermined value A1 before the start of melting of the contact surface, the time until the contact surface starts to melt can be shortened.
Furthermore, since the electromagnetic coil 11a controlled by the inverter vibrates and is pressurized by the servo motor 14b, the amplitude and the applied pressure can be arbitrarily controlled. Thereby, the amplitude and the applied pressure can be easily controlled electrically. As described above, the amplitude and the applied pressure until the start of melting of the contact surface are reduced, and the amplitude and the applied pressure after the start of melting are reduced. Control of increasing the size can be easily performed.

  In the present invention, the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present invention depending on the purpose and application. That is, in the above embodiment, the first predetermined value A1 is reached before the start of melting of the contact surface between the upper member 2 and the lower member 3, but the present invention is not limited to this. For example, FIG. As shown, the amplitude may be increased linearly over time. In this case, since the amplitude can be gradually increased from the start of vibration to the start of melting, the impact on the resin part due to vibration can be suppressed. Further, as shown in FIG. 5, it is raised with a predetermined rising gradient from the start of vibration to the start of melting of the contact surface, and then after the start of melting of the contact surface, the second gradient is increased with a rising gradient larger than the previous rising gradient. You may make it raise to a predetermined value. In this case, the amplitude can be gradually increased from the start of vibration to the start of melting, and can be quickly increased to the second predetermined value after the start of melting. Thereby, the time of the whole welding process can be shortened, suppressing the impact to the resin component by vibration.

  Moreover, in the said Example, although the relationship of control of the amplitude and pressurizing force by a control part shall be shown in FIG. 2, it is not limited to this, For example, material physical properties, such as a melting start temperature of a resin component, a heat capacity, In consideration of the contact area between the resin parts, other relations may be established.

  Furthermore, in the above embodiment, the relationship between the amplitude and the applied pressure by the control unit is shown in FIG. 2, but the present invention is not limited to this. For example, only the amplitude is controlled and the applied pressure is always a predetermined applied pressure. The amplitude and the applied pressure may be controlled independently without being associated with each other, such as a pressure.

  In the above embodiment, the vibration source 11 including the inverter-controlled electromagnetic coil 11a is used as the vibration source whose amplitude is variable. However, the present invention is not limited to this. For example, the inverter-controlled vibration motor or ultrasonic vibration generation is performed. Other vibration sources that can arbitrarily vary the amplitude, such as a vibration source using a vessel or the like, may be used.

  Furthermore, in the above-described embodiment, the lifting mechanism 14 that varies the pressure by controlling the drive torque by the servo motor 14b is used as the lifting mechanism 14 that varies the pressure. However, the present invention is not limited to this. It is good also as an raising / lowering mechanism which can change other pressurizing forces arbitrarily, such as raising / lowering mechanism which changes pressure by controlling this.

(Comparative Example 1)
By using the vibration welding apparatus 1 shown in FIG. 1, the welding of two resin parts is controlled by controlling the amplitude and the applied pressure to reach the upper limit values A2 and F2 before the contact surface starts melting as shown in FIG. Went. Specifically, A2 = 1.8, F0 = 0.5, and F2 = 2.0.

Example 1
Two resin parts were welded by the control shown in FIGS. 2 and 3 using the vibration welding apparatus 1 shown in FIG. Specifically, A1 = 0.5 and F1 = 1.4, and the other conditions were A2 = 1.8, F0 = 0.5, and F2 = 2.0, as in the comparative example.
As a result, the amount of abrasion powder generated in Example 1 was reduced to 1/10 of the amount generated in Comparative Example 1. Therefore, the effect of reducing the amount of abrasion powder generated by this example was confirmed.

  Used as a technique for vibration welding of resin parts. In particular, it is suitably used as a technique for vibration welding of parts where generation of wear powder is not preferred.

It is the schematic of the vibration welding apparatus which concerns on a present Example. It is a figure which shows the relationship between the amplitude which concerns on a present Example, and applied pressure. It is a figure which shows the amplitude and pressurization force with time passage of the vibration welding method which concerns on a present Example. It is a figure which shows the amplitude and pressurization force with time passage of the vibration welding method which concerns on other embodiment. It is a figure which shows the amplitude and pressurization force with time passage of the vibration welding method which concerns on other embodiment. It is a figure which shows the example of the amplitude and pressurization force with time passage of the conventional vibration welding method.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1; Vibration welding apparatus, 11; Vibration source, 11a; Electromagnetic coil, 11b; Inverter, 11c; Adsorption member, 11d; Leaf spring 12; Upper platen, 13: Lower platen, 14: Lifting mechanism, 14a; ; Servo motor, 14c; Lifting table, 15; Upper welding jig, 15a; Holding part, 16; Lower welding jig, 16a; Holding part, 17; Control part, 18; Lower member.

Claims (8)

In the vibration welding method in which two resin parts are brought into contact with pressure, frictional heat due to vibration is generated on the contact surface to melt the corresponding contact surface, and the two resin parts are welded.
The amplitude of the vibration is varied, and the amplitude is maintained at a predetermined value or less during at least a period from the start of vibration to the start of melting of the contact surface, and then the amplitude is set to the predetermined value after the start of melting of the contact surface. The vibration welding method is characterized in that it is increased to a value larger than that.   The vibration welding method according to claim 1, wherein the amplitude reaches the predetermined value before the start of melting of the contact surface.   The vibration welding method according to claim 1, wherein the amplitude continues to increase at a predetermined rising gradient at least during a period from the start of vibration to the start of melting of the contact surface.   4. The vibration welding method according to claim 3, wherein the amplitude is increased to a value larger than the predetermined value with a rising gradient larger than the predetermined rising gradient after the start of melting of the contact surface.   The vibration welding method according to any one of claims 1 to 4, wherein the pressure is variable with a predetermined correlation with the amplitude. A vibration welding apparatus used for the vibration welding method according to any one of claims 1 to 5,
A vibration source provided with a variable amplitude;
A vibration plate that is vibrated by being vibrated by the vibration source;
A stationary plate provided to face the vibration plate and displaceable in a direction to face the vibration plate;
A displacement mechanism for displacing the stationary plate in a direction facing the vibration plate;
A vibration-side jig fixedly attached to the vibration plate so as to hold one resin part of the two resin parts and vibrate with the vibration plate;
A stationary side jig that holds the other resin part of the two resin parts and is fixedly attached to the stationary plate;
A vibration welding apparatus comprising: a control unit that controls the vibration source and the displacement mechanism.   The vibration welding apparatus according to claim 6, wherein the vibration source is an electromagnetic vibration generator having an electromagnetic coil and an inverter that varies a high-frequency current applied to the electromagnetic coil to vary the amplitude.   The vibration welding device according to claim 6 or 7, wherein the displacement mechanism includes a ball screw and a servo motor that drives the ball screw and varies the driving torque of the driving to vary the applied pressure.

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