CN115768582A

CN115768582A - Electrode pressing mechanism of resistance welding machine, welding method and manufacturing method of electromagnetic shutter

Info

Publication number: CN115768582A
Application number: CN202180039250.4A
Authority: CN
Inventors: 松井昭夫; 庄野一弘; 曾田昇吾; 山本麻人; 鸟居博之
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2020-06-24
Filing date: 2021-01-27
Publication date: 2023-03-07
Also published as: JPWO2021260985A1; TW202200297A; JP7329691B2; WO2021260985A1; TWI774287B; TW202241620A

Abstract

The present invention provides an electrode pressing mechanism of a resistance welding machine, which can control the pressing force of a workpiece regardless of the pressing force of a resistance welding machine body, and which moves an upper electrode (2) up and down by the pressing mechanism of the resistance welding machine body, and presses and welds a pair of workpieces (30, 31) arranged between the upper electrode (2) and a lower electrode (5), the electrode pressing mechanism of the resistance welding machine being characterized by comprising: a load receiving member (6) which is provided on the lower electrode (5), is in contact with the upper electrode (2), and receives a pressure force generated by the resistance welding machine body; and a movable electrode (4) which is provided to the upper electrode (2) via an elastic member (3), which is brought into contact with the workpiece (30) during pressurization, and which controls the pressurization force applied to the workpieces (30, 31) by the pressurization force of the elastic member (3).

Description

Electrode pressing mechanism of resistance welding machine, welding method and manufacturing method of electromagnetic shutter

Technical Field

The present invention relates to an electrode pressing mechanism of a resistance welding machine, a welding method, and a method for manufacturing an electromagnetic shutter.

Background

In an electrode pressing mechanism of a conventional resistance welding machine, in order to ensure the follow-up property of a pressing electrode at the time of welding, a plurality of types of spring members having different pressing forces with respect to contraction amounts are arranged in series, and a pressing amount with respect to a pressing force to an object to be welded is ensured by weak pressing and strong pressing (for example, patent document 1).

In an electrode pressing mechanism of another resistance welding machine, in order to ensure the following property of a pressing electrode at the time of welding, a plurality of disc springs are provided in a holder guide portion which can be externally disposed thereafter, and a work (workpiece) is pressed by a spring force of the disc springs. (for example, patent document 2)

Patent document 1: japanese patent laid-open publication No. 2007-260747

Patent document 2: japanese patent laid-open publication No. H10-249540

Disclosure of Invention

However, in the electrode pressing mechanism of the resistance welding machine in patent document 1, since the range of the pressing force applied to the workpiece is determined by the structure of the spring members arranged in series, there is a problem that the corresponding range of the pressing force is limited. Further, in order to expand the corresponding range of the pressurizing force, if the pressurizing force is applied by adding the number of springs or the type of springs, the corresponding range can be expanded. Further, since the pressing force applied to the work is determined by the deflection amount of the spring members arranged in series, there is a problem that the pressure adjustment of the pressing mechanism (for example, air pressure cylinder) of the resistance welding machine main body is required.

Further, in the electrode pressing mechanism of the resistance welding machine in patent document 2, since the spring mechanism to be disposed can be mounted thereafter, the range of the pressing force to the work piece can be easily adjusted, but there is the same problem as the resistance welding machine in patent document 1. In addition, there is a problem that the pressing mechanism of the resistance welding machine main body is difficult to correspond to a strong pressing region.

The present application discloses a technique for solving the above-described problems, and an object of the present application is to provide an electrode pressing mechanism of a resistance welding machine capable of controlling a pressing force of a work by a deflection amount of a spring regardless of the pressing force of a resistance welding machine main body.

An electrode pressing mechanism of a resistance welding machine disclosed in the present application, which moves an upper electrode up and down by a pressing mechanism of a resistance welding machine main body, and presses and welds a pair of workpieces arranged between the upper electrode and a lower electrode, the electrode pressing mechanism of the resistance welding machine comprising: a load receiving member provided in the lower electrode, and contacting the upper electrode to receive a pressurizing force generated by the resistance welding machine main body; and a movable electrode provided on the upper electrode via an elastic member, and contacting the workpiece during pressing, wherein a pressing force of the elastic member is used to control the pressing force of the workpiece.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the electrode pressing mechanism of the resistance welding machine disclosed in the present application, since the pressing force of the resistance welding machine main body is received by the load receiving member and the pair of workpieces are pressed by only the elastic member provided on the upper electrode, the pressing force of the elastic member to the workpieces can be controlled by the amount of deflection of the elastic member regardless of the pressing force of the resistance welding machine main body.

Drawings

Fig. 1 is a sectional view and a plan view of essential parts showing an electrode pressing mechanism of a resistance welding machine according to embodiment 1.

Fig. 2 is a flowchart illustrating a welding method in the resistance welding machine according to embodiment 1.

Fig. 3 is a cross-sectional view showing an operating state of the resistance welding machine according to embodiment 1.

Fig. 4 is a main part cross-sectional view showing an electrode pressing mechanism of the resistance welding machine according to embodiment 2.

Fig. 5 is a main part cross-sectional view and a main part plan view showing an electrode pressing mechanism of the resistance welding machine according to embodiment 3.

Fig. 6 is a main portion plan view showing another embodiment according to embodiment 3.

Fig. 7 is a plan view of essential parts showing an electrode pressing mechanism of the resistance welding machine according to embodiment 4.

Fig. 8 is a plan view and a cross-sectional view showing a main part structure of the electric resistance welding machine according to embodiment 5.

Fig. 9 is a schematic view showing the electromagnetic switch according to embodiment 6 manufactured by using a resistance welding machine.

Detailed Description

Embodiment 1.

Next, an embodiment of an electrode pressing mechanism of a resistance welding machine according to the present invention will be described with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals.

Fig. 1 is a main sectional view showing an electrode pressing mechanism of a resistance welding machine according to embodiment 1, fig. 1 (a) is a side sectional view, and fig. 1 (B) is a sectional view taken along line B-B in fig. 1 (a).

< Structure of resistance welding machine >

In the figure, the resistance welding machine is provided with a movable part 10 and a fixed part 20, the movable part 10 is composed of a pressure plate 1 for receiving a pressurizing force generated by an air pressure cylinder (not shown) as an electrode pressurizing means of a resistance welding machine main body, an upper electrode 2 fixed just below the pressure plate 1, and a movable electrode 4 attached to a lower part of the upper electrode 2 via a spring 3 as an elastic member, and the fixed part 20 is composed of a lower electrode 5 disposed to face the movable electrode 4 with a space therebetween, and a load receiving member 6 composed of an insulating material fixed to both sides of an upper surface of the lower electrode 5 to regulate a lowering position of the upper electrode 2.

Further, an upper workpiece 30 and a lower workpiece 31 to be welded are superimposed on the upper surface of the lower electrode 5 facing the movable electrode 4 of the resistance welding machine.

Here, the distance X between the surface of the upper electrode 2 in contact with the load receiving member 6 and the surface of the movable electrode 4 in contact with the workpiece 30 is set larger than the distance Y between the surface of the load receiving member 6 in contact with the upper electrode 2 and the surface of the workpiece 30 in contact with the movable electrode 4.

The movable electrode 4 is electrically connected to the upper electrode 2, and the spring 3 is fastened by a screw (not shown) fixed to the upper electrode 2, thereby applying a pressure increase to the spring 3.

< actions of resistance welding machine >

A method of welding the upper workpiece 30 as a welding object and the lower workpiece 31 as a welding object by the resistance welding machine as described above will be described with reference to fig. 2.

First, in step ST1, the lower workpiece 31 and the upper workpiece 30 are arranged on the lower electrode 5 in a superimposed manner. Next, the air pressure cylinder, which is an electrode pressurizing means of the resistance welding machine main body, is operated to lower the upper electrode 2, and the movable electrode 4 is brought into contact with the upper workpiece 30 (step ST 2).

Then, the upper electrode 2 is lowered to bring the upper electrode 2 into contact with the load receiver 6 (step ST 3).

At this time, as shown in fig. 3, the spring 3 is deflected, and thereby the

workpieces

30 and 31 sandwiched between the movable electrode 4 and the lower electrode 5 are pressed by an appropriate pressing force. That is, since the distance X is larger than the distance Y, the pressure generated by the air pressure cylinder serving as the electrode pressurizing unit of the resistance welding machine main body is received by the load receiving member 6, and thus only the pressure of the deflection amount of the spring 3 is applied to the

workpieces

30 and 31.

Therefore, by appropriately setting the bending force of the spring 3, an appropriate pressing force can be applied to the

workpieces

30 and 31.

Next, in step ST4, if a current flows between the upper electrode 2 and the lower electrode 5, the contact portion between the upper workpiece 30 and the lower workpiece 31 generates heat due to contact resistance, and the contact portion melts and can be welded to each other (step ST 4).

Finally, the upper electrode 2 and the movable electrode 4 are raised, and the

workpieces

30 and 31 are taken out (step ST 5).

Further, although the contact portion between the upper workpiece 30 and the lower workpiece 31 is melted and slightly deformed, the movable electrode 4 is caused to follow the workpiece 30 by the spring force of the spring 3, and the pressing force to the workpiece 30 can be maintained, so that stable welding can be performed.

< background of Effect >

In general, the welding pressure is adjusted by changing the pressure of the air pressure cylinder of the resistance welding machine body, which requires adjustment because the appropriate value of the welding pressure is different depending on the material and size of the

workpieces

30 and 31 and the size of the electrode that contacts the

workpieces

30 and 31 during welding, but the time lag of starting movement of the air cylinder increases due to the frictional resistance of the internal structure of the air pressure cylinder, particularly in a region where the cylinder pressure is low, and therefore it takes time until the welding pressure is applied, and the welding cycle time increases. Further, since it is impossible to cope with a slight deformation of the welded portion at the time of energization and the following property of the electrode is deteriorated, sputtering is generated from the welded portion due to a decrease in the pressing force to the

workpieces

30 and 31, and there is a possibility that the welding quality is lowered. In addition, in order to expand the range of the appropriate pressure force of the resistance welding machine, modification of a pressure mechanism of the equipment or introduction of a new resistance welding machine can be used.

< description of the Effect >

In contrast, in embodiment 1, since the pressure force of the air pressure cylinder, which is the electrode pressure means of the resistance welding machine main body, is received by the load receiving member 6, the pressure force applied to the

workpieces

30 and 31 can be controlled only by the spring 3 regardless of the electrode pressure means of the resistance welding machine main body. Therefore, since the material and thickness of the

workpieces

30 and 31 and the areas of the movable electrode 4 and the lower electrode 5 in contact with the

workpieces

30 and 31 are different from each other, even when a pressing force outside the appropriate pressing range of the apparatus is required, the spring 3 can be changed or the amount of deflection of the spring 3 can be adjusted by a screw, and thus, the equipment investment can be suppressed.

Further, since the

workpieces

30 and 31 are pressed by pressing the movable electrode 4 with the spring 3, the small deformation of the welded portion at the time of energization can be dealt with only by following the movable electrode 4 with the spring 3, and there is no need to follow the platen 1 and the upper electrode 2, so that the inertia force is small and the following performance of the pressing force can be improved.

Further, since the load receiving member 6 receives the pressurizing force of the resistance welding machine main body, the spring 3 does not receive an excessive load, and the spring 3 can be prevented from being damaged.

Therefore, the electrode pressing mechanism of the resistance welding machine can be obtained with low cost and good performance.

In addition, the parallelism of the upper electrode 2 and the lower electrode 5 can be adjusted by the height of the load receiver 6, and thus the adjustment is easy. The arrangement of the load receiving members 6 is not limited to the left and right portions 2, and similar effects can be obtained even if a plurality of load receiving members are arranged in a well-balanced manner on the outer peripheral side of the lower electrode 5.

Embodiment 2.

In the figure, the movable electrode 4 is composed of a movable electrode main body 4a having a recess, and a replaceable electrode 4b which is attached to the recess of the movable electrode main body 4a by a screw (not shown) and is detachable by being pressed by a workpiece 30. Here, the movable electrode body 4a is set to a size that does not contact the workpiece 30 during welding.

With the above configuration, when the electrode surface is damaged or contaminated, only the replacement electrode 4b can be removed and replaced, and therefore maintenance cost can be reduced. In addition, when the welding electrode needs to be replaced due to wear of the electrode, only the replacement electrode 4b that is in direct contact with the workpiece 30 needs to be replaced, and therefore, the method can be economically used.

Embodiment 3.

Fig. 5 is a main part cross-sectional view showing an electrode pressing mechanism of the resistance welding machine according to embodiment 3.

In the figure, the movable electrode 4 is connected to the upper electrode 2 by a spring 3 provided at an angle of 4.

Since the pressurizing force is applied by the 4 springs by arranging the springs 3 at the 4-degree angle as described above, the height of the springs is suppressed, the distance between the movable electrode 4 and the lower electrode 5 can be increased, and welding can be performed even on the

workpieces

30 and 31 having a height. Further, when the

workpieces

30 and 31 are pressurized, the movable electrode 4 follows the contact surface of the workpiece 30, and the influence of the inclination of the workpiece 30 or the parallelism between the upper and lower electrodes can be suppressed, and stable welding can be performed by reducing the shortage and nonuniformity of the pressurizing force.

The springs 3 may not be provided at the positions of the 4-angle corners of the movable electrode 4, respectively, and may be arranged in a well-balanced manner so that the pressing force of each spring becomes uniform when a plurality of springs are pressed. For example, as shown in fig. 6 (a), the springs may be arranged at 3 points at equal intervals when the movable electrode 4 is circular, or may be arranged at 2 points on the left and right sides when the movable electrode is rectangular as shown in fig. 6 (B).

Embodiment 4.

Fig. 7 is a plan view showing a main structure of an electrode pressing mechanism of the resistance welding machine according to embodiment 4.

In embodiment 1, the load receiving members 6 are disposed on the left and right sides 2 of the lower electrode 5, but may be disposed on the outer peripheral side 3 of the upper surface of the lower electrode 5 as shown in fig. 7, so that the same effect as that of facilitating the adjustment of the parallelism of the upper electrode 2 and the lower electrode 5 can be obtained.

In the above embodiment, the contact pressure is applied to the

workpieces

30 and 31 by using the spring 3, but the present invention can be similarly configured by using an elastic member such as rubber or an elastically deformable resin molded product.

Embodiment 5.

Fig. 8 is a plan view and a cross-sectional view showing a main structure of an electrode pressing mechanism of the resistance welding machine according to embodiment 5, and as shown in fig. 8 (B), a load receiving member 6 is configured by a load receiving portion 6a made of an insulating resin on the upper electrode 2 side and a load receiving portion 6B made of a metal material supporting the load receiving portion 6a so that a current does not flow from the upper electrode 2 to the lower electrode 5 via the load receiving member 6.

Further, by sandwiching a spacer between the load receiving portion 6a and the load receiving portion 6b, the pressurizing force generated by the spring 3 can be adjusted. Further, a metal having a high longitudinal elastic coefficient can be used for the load receiving portion 6b, and the amount of deformation can be suppressed to be small, thereby further improving the management of the pressurizing force.

Embodiment 6.

Fig. 9 is a schematic view showing the electromagnetic switch according to embodiment 6 manufactured by using the resistance welding machine.

In the drawing, a pair of work pieces manufactured by the welding method described above, i.e., a magnetic spacer 101 and a movable iron core 102, are used for an electromagnetic shutter 100. Here, the movable core 102 is made of a ferrous magnetic metal, for example, SS400, which is a general structural rolled material, and the magnetic spacer 101 is made of a thin plate of a ferrous magnetic metal and a stainless steel material, which is a non-magnetic metal that is easily welded, particularly an austenitic stainless steel material such as SUS 304.

The electromagnetic shutter 100 is configured to include the following components: a resin molded article 103 which is an insulator supporting the movable core 102; a movable contact 104 fixed to the resin molded product 103; an electromagnet 105 that attracts the movable core 102; a spring 106 that urges the movable core 102 so as to be separated from the fixed core 105a of the electromagnet 105; and a housing 108 that houses the respective members and fixes the fixed contacts 107 to the movable contacts 104.

With the above-described configuration, if the electromagnet 105 is energized, a magnetic flux is formed by the pair of driving coils, and this magnetic flux forms a magnetic path that returns from one fixed core 105a of the electromagnet 105 to the other fixed core 105a through the magnetic spacer 101 and the movable core 102, whereby the movable core 102 is attracted by the fixed core 105a against the pressure of the spring 106 by this magnetic flux, and as a result, the movable contact 104 comes into contact with the fixed contact 107, and the electric circuit is closed.

Next, if the current of the driving coil is turned off, the magnetic flux generated by the driving coil disappears, but if there is no air gap between the movable core 102 and the fixed core 105a, residual magnetism is generated between the movable core 102 and the fixed core 105a due to the coercive force of the materials of the two, and the spring 106 cannot overcome the attraction force, and there is a possibility that the opening operation of the electric circuit cannot be performed.

However, since the magnetic spacer 101 made of a non-magnetic material is provided, the portion where the magnetic spacer 101 exists is regarded as an air gap in the magnetic circuit, and therefore, the coercive force of the materials of the movable core 102 and the fixed core 105a is exceeded, and a reverse magnetic field is applied to both cores, and an effect of making the residual magnetic flux substantially zero is obtained. As a result, the spring 106 can push up the movable core 102, and the movable core 102 is separated from the fixed core 105a, thereby disconnecting the electric circuit.

As described above, the magnetic spacer 101 and the movable core 102 of the electromagnetic switch are welded by using the resistance welding machine disclosed in the present application, and as a result, a low-cost and high-performance electromagnetic switch can be obtained.

The present application is not limited to embodiment 1 described above, and the various features, modes, and functions described in embodiment 1 are not limited to the application to a specific embodiment, and may be applied to the embodiments individually or in various combinations. Therefore, numerous modifications not illustrated are conceivable within the technical scope disclosed in the specification of the present application. Examples of the case include a case where at least 1 component is modified, added, or omitted, and a case where at least 1 component is extracted and combined with the components of other embodiments.

Description of the reference numerals

1: pressing plate, 2: upper electrode, 3: elastic member (spring), 4: movable electrode, 4a: movable electrode main body, 4b: replacement of electrodes, 5: lower electrode, 6: load receiving member, 6a, 6b: load receiving part, 10: movable portion, 20: fixing portion, 30, 31: workpiece (welded article), 100: electromagnetic shutter, 101: gasket, 102: movable iron core

Claims

1. An electrode pressing mechanism of a resistance welding machine, which moves an upper electrode up and down by a pressing mechanism of a resistance welding machine main body to press and weld a pair of workpieces arranged between the upper electrode and a lower electrode,

the electrode pressing mechanism of the resistance welding machine comprises:

a load receiving member provided in the lower electrode, in contact with the upper electrode, and receiving a pressure generated by the resistance welding machine body; and a movable electrode provided on the upper electrode via an elastic member and contacting the workpiece when pressurized,

the pressing force of the workpiece is controlled by the pressing force of the elastic member.

2. The electrode pressing mechanism of a resistance welding machine according to claim 1,

the distance between the surface of the upper electrode in contact with the load receiving member and the surface of the movable electrode in contact with the workpiece is larger than the distance between the surface of the load receiving member in contact with the upper electrode and the surface of the workpiece in contact with the movable electrode.

3. The electrode pressing mechanism of a resistance welding machine according to claim 1,

the movable electrode is in contact with the workpiece to pressurize the workpiece before the upper electrode is moved into contact with the load receiver.

4. The electrode pressing mechanism of a resistance welding machine according to any one of claims 1 to 3,

the movable electrode is composed of a movable electrode main body and a replacement electrode which is fixed to the movable electrode main body and can be detached by being pressed by the workpiece.

5. The electrode pressing mechanism of a resistance welding machine according to any one of claims 1 to 4,

a plurality of the elastic members are disposed between the upper electrode and the movable electrode.

6. The electrode pressing mechanism of an electric resistance welding machine according to any one of claims 1 to 5,

a plurality of load receiving members for receiving a pressing force generated by the resistance welding machine body are arranged on an outer circumferential side of the lower electrode.

7. The electrode pressing mechanism of a resistance welding machine according to any one of claims 1 to 6,

the load receiving member includes a load receiving portion made of an insulating resin on the upper electrode side and a load receiving portion made of a metal material for supporting the load receiving portion.

8. The electrode pressing mechanism of a resistance welding machine according to any one of claims 1 to 7,

the elastic member is constituted by a spring.

9. A resistance welding machine is characterized in that,

an electrode pressing mechanism having the resistance welding machine according to any one of claims 1 to 8.

10. A welding method using the resistance welding machine according to claim 9,

the welding method is characterized by comprising the following steps:

a step 1 of disposing a pair of workpieces between the upper electrode and the lower electrode; a 2 nd step of moving the upper electrode to bring the movable electrode into contact with the workpiece; a 3 rd step of pressing the pair of workpieces by further moving the upper electrode to bring the upper electrode into contact with a load receiver; and a 4 th step of welding the pair of workpieces by applying current between the upper electrode and the lower electrode.

11. A method for manufacturing an electromagnetic shutter, characterized in that,

the welding method according to claim 10, wherein the movable core of the electromagnetic shutter and the spacer made of a nonmagnetic metal are welded to each other.