Electrode pressurizing mechanism of resistance welding machine, resistance welding machine and welding method, and manufacturing method of electromagnetic on-off switch

Abstract

The electrode pressurizing mechanism of the resistance welding machine according to the present invention is characterized by comprising: a load receiving member (6) provided to a lower electrode (5) and receiving a pressurizing force generated by a resistance welding machine main body when the load receiving member (6) is in contact with an upper electrode (2); and a movable electrode (4) provided to the upper electrode (2) via an elastic member (3) and in contact with a workpiece (30) when pressurizing, the pressurizing force of the workpiece (30, 31) being controlled by the pressurizing force of the elastic member (3).

Description

Technical Field

[0001] This application relates to the electrode pressure mechanism of a resistance welding machine, the resistance welding machine and welding method, and the manufacturing method of an electromagnetic switch. Background Technology

[0002] In the electrode pressure mechanism of existing resistance welding machines, in order to ensure the following of the pressure electrode during welding, multiple types of spring components with different pressure for shrinkage are arranged in series, and the amount of pressure applied to the workpiece is ensured by applying weak pressure and strong pressure (for example, Patent Document 1).

[0003] In addition, in the electrode pressurization mechanism of other resistance welding machines, in order to ensure the following of the pressurized electrode during welding, multiple disc springs are provided in the cage guide section that can be externally mounted thereafter. The spring force of these disc springs applies pressure to the workpiece to be welded. (For example, Patent Document 2)

[0004] Patent Document 1: Japanese Patent Application Publication No. 2007-260747

[0005] Patent Document 2: Japanese Patent Application Publication No. 10-249540 Summary of the Invention

[0006] However, regarding the electrode pressure mechanism of the resistance welding machine in Patent Document 1 mentioned above, the range of pressure applied to the workpiece is determined by the structure of the spring components arranged in series, thus limiting the corresponding range of pressure. Furthermore, while increasing the number or type of springs can expand the corresponding range of pressure, this also results in a larger pressure mechanism. Moreover, since the pressure applied to the workpiece is determined by the deflection of the spring components arranged in series, pressure adjustment of the pressure mechanism (e.g., an air pressure cylinder) of the resistance welding machine body is required.

[0007] Furthermore, regarding the electrode pressure mechanism of the resistance welding machine in Patent Document 2, the spring mechanism to be configured can be installed subsequently, thus the range of pressure applied to the workpiece can be easily adjusted, but it suffers from the same problem as the resistance welding machine in Patent Document 1. Additionally, there is a difficulty in corresponding the area of ​​high pressure to the pressure mechanism of the main body of the resistance welding machine.

[0008] This application discloses a technology for solving the above-mentioned problems, the purpose of which is to obtain an electrode pressure mechanism for a resistance welding machine that can control the pressure applied to the workpiece by means of the deflection of a spring, independent of the pressure applied to the main body of the resistance welding machine.

[0009] The electrode pressurizing mechanism of the resistance welding machine disclosed in this application moves the upper electrode up and down through the pressurizing mechanism of the resistance welding machine body to pressurize and weld a pair of workpieces arranged between the upper electrode and the lower electrode. The electrode pressurizing mechanism of the resistance welding machine is characterized by having a load-bearing member, which is disposed on the lower electrode and connected to the upper electrode to bear the pressure generated by the resistance welding machine body.

[0010] The effects of the invention

[0011] According to the electrode pressurization mechanism of the resistance welding machine disclosed in this application, a resistance welding machine can be obtained in which the load-bearing member bears the pressure of the resistance welding machine body, and the pressure is applied to a pair of workpieces by only the elastic member provided on the upper electrode. Therefore, the pressure applied to the workpieces can be controlled by the deflection of the elastic member, regardless of the pressure of the resistance welding machine body. Attached Figure Description

[0012] Figure 1 These are partial cross-sectional views and partial top views of the electrode pressure mechanism of the resistance welding machine according to Embodiment 1.

[0013] Figure 2 This is a flowchart illustrating the welding method in the resistance welding machine according to Embodiment 1.

[0014] Figure 3 This is a cross-sectional view showing the operating state of the resistance welding machine according to Embodiment 1.

[0015] Figure 4 This is a partial cross-sectional view showing the electrode pressure mechanism of the resistance welding machine according to Embodiment 2.

[0016] Figure 5 These are partial cross-sectional views and partial top views of the electrode pressure mechanism of the resistance welding machine according to Embodiment 3.

[0017] Figure 6 This is a top view showing the main parts of other embodiments involved in Embodiment 3.

[0018] Figure 7 This is a top view showing the main part of the electrode pressure mechanism of the resistance welding machine according to Embodiment 4.

[0019] Figure 8 These are top views and cross-sectional views showing the main structure of the resistance welding machine according to Embodiment 5.

[0020] Figure 9 This is a schematic diagram showing the electromagnetic switch involved in Embodiment 6, which is manufactured using a resistance welding machine. Detailed Implementation

[0021] Implementation method 1.

[0022] The following description uses the accompanying drawings to illustrate an embodiment of the electrode pressure mechanism of the resistance welding machine according to this application. Furthermore, in each drawing, identical or equivalent parts are labeled with the same reference numerals.

[0023] Figure 1 This is a cross-sectional view showing the main parts of the electrode pressure mechanism of the resistance welding machine according to Embodiment 1. Figure 1 (A) is a side sectional view. Figure 1 (B) is along Figure 1 A sectional view of line B-B in (A).

[0024] <Structure of Resistance Welding Machine>

[0025] In the figure, the resistance welding machine is provided with a movable part 10 and a fixed part 20. The movable part 10 consists of a pressure plate 1 that bears the pressure generated by the electrode pressurization unit, i.e., the air pressure cylinder (not shown), which passes through the body of the resistance welding machine, an upper electrode 2 fixed directly below the pressure plate 1, and a movable electrode 4 installed at the lower part of the upper electrode 2 via an elastic member, i.e., a spring 3. The fixed part 20 consists of a lower electrode 5 that is spaced apart from the movable electrode 4 and arranged opposite to it, and a load-bearing member 6 made of insulating material that is fixed to both sides of the upper surface of the lower electrode 5 to limit the descent position of the upper electrode 2.

[0026] In addition, on the upper surface of the lower electrode 5, which is opposite to the movable electrode 4 of the resistance welding machine, the upper workpiece 30 and the lower workpiece 31 to be welded are stacked and arranged.

[0027] Here, the distance X between the surface of the upper electrode 2 that contacts the load-bearing member 6 and the surface of the movable electrode 4 that contacts the workpiece 30 is set to be larger than the distance Y between the surface of the load-bearing member 6 that contacts the upper electrode 2 and the surface of the workpiece 30 that contacts the movable electrode 4.

[0028] Furthermore, the movable electrode 4 is configured to be 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 pressure to the spring 3.

[0029] <Operation of Resistance Welding Machine>

[0030] use Figure 2 The method of welding the workpiece 30 (the upper workpiece) to the workpiece 31 (the lower workpiece) using the resistance welding machine described above will be explained.

[0031] First, in step ST1, the lower workpiece 31 and the upper workpiece 30 are stacked and arranged on the lower electrode 5. Next, the electrode pressurization unit, i.e., the air pressure cylinder, of the resistance welding machine body is activated to lower the upper electrode 2, so that the movable electrode 4 comes into contact with the upper workpiece 30 (step ST2).

[0032] Furthermore, the upper electrode 2 is lowered so that it comes into contact with the load-bearing member 6 (step ST3).

[0033] At this time, as Figure 3 As shown, the spring 3 flexes, thereby pressing the workpieces 30 and 31, which are clamped by the movable electrode 4 and the lower electrode 5, with appropriate pressure. That is, the distance X mentioned above is greater than the distance Y, so the pressure generated by the electrode pressing unit, i.e., the air pressure cylinder, of the resistance welding machine body is borne by the load-bearing component 6, thereby applying pressure to the workpieces 30 and 31 only by the deflection of the spring 3.

[0034] Therefore, by appropriately setting the flexural force of spring 3, it is possible to apply appropriate pressure to workpieces 30 and 31.

[0035] Next, in step ST4, if current flows between the upper electrode 2 and the lower electrode 5, the contact portion of the upper workpiece 30 and the lower workpiece 31 heats up through the contact resistance, thereby melting the contact portion and enabling the two to be welded (step ST4).

[0036] Finally, the upper electrode 2 and the movable electrode (4) are raised to remove the workpieces 30 and 31 (step ST5).

[0037] Furthermore, the contact area between the upper workpiece 30 and the lower workpiece 31 melts and undergoes slight deformation, but the movable electrode 4 follows the workpiece 30 due to the spring force of the spring 3, which can maintain the pressure applied to the workpiece 30, thus enabling stable welding.

[0038] <Background of the effect>

[0039] Generally, the appropriate value of the welding pressure varies depending on the material and size of the workpieces 30 and 31, as well as the size of the electrodes contacting them during welding. Therefore, adjustments are necessary. In this case, the pressure can be adjusted by changing the pressure of the air pressure cylinder in the resistance welding machine body. However, due to the frictional resistance of the internal structure of the air pressure cylinder, especially in areas with low cylinder pressure, the lag in cylinder movement increases, thus increasing the time required to apply pressure and extending the welding cycle time. Furthermore, it cannot handle the minute deformations of the weld area when energized, leading to deteriorated electrode tracking. Consequently, spatter may occur from the weld area due to the reduced pressure applied to the workpieces 30 and 31, potentially reducing weld quality. While expanding the appropriate range of the resistance welding machine's pressure can be achieved by modifying the pressurization mechanism or introducing a new resistance welding machine, this presents the challenge of requiring equipment investment.

[0040] <Explanation of Effects>

[0041] In contrast, in Embodiment 1 described above, the pressure applied by the electrode pressurizing unit (i.e., the air pressure cylinder) of the resistance welding machine body is borne by the load-bearing component 6. Therefore, the pressure applied to the workpieces 30 and 31 is independent of the electrode pressurizing unit of the resistance welding machine body and is controlled solely by the spring 3. Thus, even if the material, thickness, and areas of the movable electrode 4 and lower electrode 5 connected to the workpieces 30 and 31 differ, the spring 3 can be modified or its deflection adjusted by screws even when the required pressure is outside the appropriate range, thereby reducing equipment investment.

[0042] In addition, workpieces 30 and 31 are pressed by the movable electrode 4 by the spring 3. Therefore, the small deformation of the welded part when energized can be responded to by the movable electrode 4 following the spring 3, without the need for the pressure plate 1 and the upper electrode 2 to follow. Therefore, the inertial force is small and the following performance of the applied pressure is good.

[0043] Furthermore, since the load-bearing component 6 bears the pressure applied by the resistance welding machine body, the spring 3 will not bear excessive load, thus preventing damage to the spring 3.

[0044] Therefore, it is possible to obtain an electrode pressure mechanism for a low-cost and high-performance resistance welding machine.

[0045] Furthermore, the parallelism between the upper electrode 2 and the lower electrode 5 can be adjusted by the height of the load-bearing member 6, making adjustment easy. Additionally, the arrangement of the load-bearing member 6 is not limited to the left and right positions; even if multiple members are evenly and evenly arranged on the outer periphery of the lower electrode 5, the same effect can be achieved.

[0046] Implementation method 2.

[0047] Figure 4 This is a partial cross-sectional view showing the electrode pressure mechanism of the resistance welding machine according to Embodiment 2.

[0048] In the figure, the movable electrode 4 consists of a movable electrode body 4a with a recess and a replaceable electrode 4b that is mounted to the recess of the movable electrode body 4a by a screw (not shown) and can be removed by pressing it with the workpiece 30. Here, the movable electrode body 4a is set to be different in size from the workpiece 30 during welding.

[0049] With the configuration described above, when damage or contamination occurs on the electrode surface, only the replacement electrode 4b needs to be removed and replaced, thus reducing maintenance costs. Furthermore, if the welding electrode needs to be replaced due to wear, only the replacement electrode 4b, which is in direct contact with the workpiece 30, needs to be replaced, thus achieving economic efficiency.

[0050] Implementation method 3.

[0051] Figure 5 This is a partial cross-sectional view showing the electrode pressure mechanism of the resistance welding machine according to Embodiment 3.

[0052] In the figure, the upper electrode 2 is connected by springs 3 set at the four corners of the movable electrode 4.

[0053] As described above, springs 3 are positioned at the four corners, thereby applying pressure through the four springs. This suppresses the height of the springs and increases the distance between the movable electrode 4 and the lower electrode 5, enabling welding even on workpieces 30 and 31 with varying heights. Furthermore, when pressure is applied to workpieces 30 and 31, the movable electrode 4 follows the contact surface of workpiece 30, suppressing the effects of the tilt of workpiece 30 or the parallelism between the upper and lower electrodes. By reducing insufficient and uneven pressure, stable welding can be achieved.

[0054] Furthermore, the springs 3 do not necessarily need to be positioned at the four corners of the movable electrode 4; they can be arranged in a balanced manner so that the applied force of each spring becomes uniform when multiple springs are compressed. For example, as long as... Figure 6 As shown in (A), when the movable electrode 4 is circular, the spring is positioned at three equally spaced points. Additionally, as... Figure 6 As shown in (B), in the case of rectangular electrodes, they can be positioned at two points on the left and right.

[0055] Implementation method 4.

[0056] Figure 7 This is a top view showing the main structure of the electrode pressure mechanism of the resistance welding machine according to Embodiment 4.

[0057] In the above embodiment 1, the load-bearing member 6 is positioned at the left and right positions of the lower electrode 5, but it can also be arranged as follows: Figure 7 The electrode is positioned on the outer periphery 3 of the upper surface of the lower electrode 5, which provides the same effect as making it easier to adjust the parallelism between the upper electrode 2 and the lower electrode 5.

[0058] Furthermore, in the above embodiment, the spring 3 is used to apply contact pressure to the workpieces 30 and 31, but the same configuration can also be achieved by using elastic components such as rubber or resin molded articles that can be elastically deformed.

[0059] Implementation method 5.

[0060] Figure 8 These are top views and cross-sectional views showing the main structure of the electrode pressure mechanism of the resistance welding machine according to Embodiment 5, such as... Figure 8 As shown in (B), the load-bearing member 6 is composed of a load-bearing part 6a made of insulating resin on the upper electrode 2 side and a load-bearing part 6b made of metal material that supports the load-bearing part 6a, so that current does not flow from the upper electrode 2 to the lower electrode 5 through the load-bearing member 6.

[0061] Furthermore, a shim is sandwiched between the load-bearing parts 6a and 6b, thereby allowing adjustment of the applied force generated by the spring 3. Moreover, by using a metal with a high longitudinal elastic modulus in the load-bearing part 6b, deformation can be minimized, further improving pressure management.

[0062] Implementation method 6.

[0063] Figure 9 This is a schematic diagram showing the electromagnetic switch according to Embodiment 6, which is manufactured using the resistance welding machine described above.

[0064] In the figure, the electromagnetic switch 100 uses a pair of workpieces manufactured by the above-described welding method, namely a magnetic pad 101 and a movable iron core 102. Here, the movable iron core 102 is made of a ferrous magnetic metal, such as a general-purpose rolled material, namely SS400, and the magnetic pad 101 is made of a sheet of a ferrous magnetic metal and a non-magnetic metal that is easy to weld, namely stainless steel, especially austenitic stainless steel such as SUS304.

[0065] In addition, the electromagnetic switch 100 is composed of the following components: a resin molded article 103, which is an insulator supporting the movable iron core 102; a movable contact 104, which is fixed to the resin molded article 103; an electromagnet 105, which attracts the movable iron core 102; a spring 106, which applies force to the movable iron core 102 to move it away from the fixed iron core 105a of the electromagnet 105; and a housing 108, which houses the components and fixes the fixed contact 107 opposite to the movable contact 104.

[0066] Based on the structure described above, if the electromagnet 105 is energized, a magnetic flux is formed through a pair of drive coils. This magnetic flux forms a magnetic circuit from one fixed iron core 105a of the electromagnet 105 through the magnetic pad 101 and the movable iron core 102 back to the other fixed iron core 105a. Thus, the movable iron core 102 is attracted to the fixed iron core 105a by the resistance of the spring 106 through this magnetic flux. As a result, the movable contact 104 contacts the fixed contact 107 and closes the electrical circuit.

[0067] Next, if the current in the drive coil is disconnected, the magnetic flux generated by the drive coil disappears. However, in the absence of an air gap between the movable iron core 102 and the fixed iron core 105a, residual magnetism is generated between them due to the coercive magnetic force of the materials of the movable iron core 102 and the fixed iron core 105a. The spring 106 cannot overcome the attraction force and may be unable to disconnect the electrical circuit.

[0068] However, by providing a magnetic pad 101 made of a non-magnetic material, the portion of the magnetic pad 101 present is considered equivalent to an air gap in the magnetic circuit. Therefore, exceeding the coercive force of the materials of the movable core 102 and the fixed core 105a, a reverse magnetic field is applied to the two cores, resulting in the effect of setting the residual magnetic flux approximately to zero. As a result, the movable core 102 can be pushed up by the spring 106, separating it from the fixed core 105a and disconnecting the electrical circuit.

[0069] As described above, the magnetic pad 101 and movable iron core 102 of the electromagnetic switch are welded together using the resistance welding machine disclosed in this application, thereby obtaining a low-cost and high-performance electromagnetic switch.

[0070] Furthermore, this application is not limited to the above-described embodiment 1, and the various features, methods, and functions described in embodiment 1 are not limited to the application of a specific embodiment, but can also be applied to the embodiment individually or in various combinations. Therefore, numerous modifications not illustrated are contemplated within the scope of the technology disclosed in this application specification. These include cases of modifying at least one structural element, adding or omitting it, and extracting at least one structural element and combining it with structural elements of other embodiments.

[0071] Explanation of the label

[0072] 1: Pressure plate; 2: Upper electrode; 3: Elastic component (spring); 4: Movable electrode; 4a: Movable electrode body; 4b: Replacement electrode; 5: Lower electrode; 6: Load-bearing component; 6a, 6b: Load-bearing parts; 10: Movable part; 20: Fixed part; 30, 31: Workpiece (welded part); 100: Electromagnetic switch; 101: Gasket; 102: Movable iron core

Claims

1. An electrode pressurizing mechanism for a resistance welding machine, wherein an upper electrode is moved up and down by a pressurizing mechanism in the main body of the resistance welding machine to pressurize a pair of workpieces positioned between the upper and lower electrodes, and welding is performed by heating the contact portion between the pair of workpieces by a current flowing between the upper and lower electrodes. The electrode pressure mechanism of this resistance welding machine is characterized by, It has a load-bearing component, which is disposed on the lower electrode and connected to the upper electrode to withstand the pressure generated by the resistance welding machine body. The load-bearing component includes a load-bearing part made of insulating resin. The device has a movable electrode that is electrically contacted by the upper electrode via an elastic member and comes into contact with the workpiece when pressure is applied. The pressure applied to the workpiece is controlled by the pressure applied by the elastic member. Before the upper electrode is moved to contact the load-bearing component, the movable electrode contacts the workpiece and applies pressure to the workpiece until the upper electrode contacts the load-bearing component.

2. The electrode pressure mechanism of the resistance welding machine according to claim 1, characterized in that, The distance between the surface of the upper electrode that contacts the load-bearing member and the surface of the movable electrode that contacts the workpiece is greater than the distance between the surface of the load-bearing member that contacts the upper electrode and the surface of the workpiece that contacts the movable electrode.

3. The electrode pressure mechanism of the resistance welding machine according to claim 1 or 2, characterized in that, The movable electrode consists of a movable electrode body and a replaceable electrode, which is fixed to the movable electrode body and can be removed by pressing the workpiece.

4. The electrode pressure mechanism of the resistance welding machine according to any one of claims 1 to 3, characterized in that, The elastic component is configured to be disposed between the upper electrode and the movable electrode.

5. The electrode pressure mechanism of the resistance welding machine according to any one of claims 1 to 4, characterized in that, Multiple load-bearing components are arranged on the outer periphery of the lower electrode to withstand the applied pressure generated by the resistance welding machine body.

6. The electrode pressure mechanism of the resistance welding machine according to any one of claims 1 to 5, characterized in that, The load-bearing component is composed of a load-bearing portion made of insulating resin on the upper electrode side and a load-bearing portion made of metal material that supports the load-bearing portion.

7. The electrode pressure mechanism of the resistance welding machine according to any one of claims 1 to 6, characterized in that, The elastic component is made of a spring.

8. A resistance welding machine, characterized in that, An electrode pressure mechanism of a resistance welding machine as described in any one of claims 1 to 7.

9. A welding method using the resistance welding machine of claim 8. The welding method is characterized by having: Step 1: A pair of workpieces are placed between the upper electrode and the lower electrode; Step 2: The upper electrode is moved so that the movable electrode placed on the upper electrode contacts the workpieces; Step 3: The upper electrode is moved further so that it contacts the load-bearing component, and pressure is applied to the pair of workpieces; and Step 4: Electricity is applied between the upper electrode and the lower electrode to weld the pair of workpieces.

10. A method for manufacturing an electromagnetic switch, characterized in that, Using the welding method described in claim 9, the movable iron core of the electromagnetic switch and the gasket made of non-magnetic metal are welded together.

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