Terminal block, vehicle driving device using same, and terminal block holder manufacturing method

Abstract

A terminal block (100) comprising a plurality of bus bars (101) each having formed at the ends thereof connection parts (104, 105) for electrically connecting to an apparatus, and a holder (102) formed of an insulating material and having a bus bar accommodation part in which recesses each having an internal side part (106) and an internal bottom part (107) are formed so as to accommodate the bus bars, and first protrusions (108, 109) which support the bus bars are formed on the internal bottom parts.

Description

Terminal block, vehicle drive device using the same, and method for manufacturing terminal block holder

[0001] The present application relates to a terminal block, a vehicle drive device using the same, and a method for manufacturing a terminal block holder.

[0002] Terminal blocks connected to rotating electric machines for drive devices of electric vehicles are susceptible to the effects of road conditions and vibrations from the engine, and therefore require a highly accurate structure that minimizes the generation of initial stress when assembling connected components to prevent a decrease in strength due to fatigue.The following prior art document proposes providing a hook on a resin-molded terminal block to prevent deformation of the bus bar during insert molding and achieve a highly accurate structure.

[0003] JP 2009-43610 A

[0004] However, in the method of Patent Document 1, the bus bar abuts against a wide surface of the holder, which is a resin member. This means that the holder becomes large, especially for long bus bars, and is susceptible to warping during resin molding, which raises concerns about poor positional accuracy of the connection points with other components.

[0005] The present disclosure has been made to solve the above problems, and aims to provide a terminal block and a vehicle drive device using the same that can improve the accuracy of a terminal block connected to a rotating electric machine used in a drive device for an electric vehicle, thereby suppressing stress generated inside the terminal block and thereby improving reliability.

[0006] The terminal block according to the present disclosure is characterized in that it has a plurality of bus bars each having a connection portion formed at its end for electrically connecting to a device, a bus bar accommodating portion having a recess having an inner portion and an inner bottom portion formed therein to accommodate the bus bars, a holder formed of an insulating material, and a first protrusion formed on the inner bottom portion for supporting the bus bars.

[0007] In the terminal block according to the present disclosure, the first protrusions that support the bus bar are formed on the inner bottom, so that the positions of the connection portions provided on both ends of the bus bar can be accurately determined by adjusting only the first protrusions, thereby reducing the initial stress when connecting to a device and improving reliability.

[0008] 1 is a perspective view of a terminal block according to a first embodiment. FIG. 2 is a plan view of the terminal block according to the first embodiment as seen from the bus bar side. FIG. 3 is a projected plan view of the terminal block according to the first embodiment in a state before the bus bar is arranged. FIG. 4 is a projected view of the terminal block according to the first embodiment along the A-A cross section of FIG. 2. FIG. 5 is a plan view of the terminal block according to the first embodiment as seen from the outer bottom of the holder. FIG. 6 is a projected view of the terminal block according to the first embodiment along the B-B cross section of FIG. 2. FIG. 7 is a projected view of the terminal block according to the first embodiment along the C-C cross section of FIG. 2. FIG. 8 is a view showing a state in which the terminal block according to the first embodiment is assembled to a rotating electric machine. FIG. 9 is a view showing a state in which the terminal block according to the first embodiment and a wiring board of the rotating electric machine are connected. FIG. 10 is a view showing a state in which the harness holding portion of the terminal block according to a second embodiment is shown.

[0009] Hereinafter, preferred embodiments of a terminal block and a vehicle drive device using the same according to the present disclosure will be described with reference to the drawings. The same components and corresponding parts are designated by the same reference numerals, and detailed descriptions thereof will be omitted. Similarly, in the following embodiments, redundant descriptions of components designated by the same reference numerals will be omitted.

[0010] Embodiment 1. Fig. 1 is a perspective view of a terminal block according to Embodiment 1. The terminal block 100 is attached to a rotating electric machine used in electric vehicles, particularly electric automobiles and hybrid electric vehicles, and includes a bus bar 101 for electrically connecting to equipment mounted on the vehicle, a holder 102 molded from an insulating resin material such as polyphenylene sulfide to hold the bus bar 101, and a bracket 103 for attaching the holder 102 to a case of the rotating electric machine. Both ends of the bus bar 101 are provided with connection portions 104 for fastening the bus bar 101 to equipment mounted on the vehicle with bolts, and connection portions 105 for connecting the bus bar 101 to the rotating electric machine by TIG (Tungsten Inert Gas) welding or the like. Fig. 2 is a plan view from the bus bar 101 side, and the above-described details can be similarly confirmed.

[0011] 3 is a plan view of the terminal block before bus bars 101 are placed in the holder 102. A recessed bus bar accommodating portion is formed in the holder 102 so that each bus bar 101 can be accommodated therein. The bus bar accommodating portion has an inner portion 106 and an inner bottom portion 107 (see also FIG. 1 ), and each bus bar 101 can be inserted and placed from above. The inner bottom portion 107 of each bus bar accommodating portion is formed with protrusions 108 and 109 (these are referred to as first protrusions) that support the bottom surface of the bus bar 101, and protrusions 110 (second protrusions) that abut against both sides of the bus bar 101. The protrusions 110 are formed at opposing positions on both sides of the inner portion 106 of the recessed bus bar accommodating portion, and are shaped so that the distance between the opposing protrusions 110 narrows from the top of the bus bar accommodating portion toward the inner bottom portion 107 (see the shape of the protrusions 110 shown in FIG. 4 (the cross-sectional view taken along the line A-A in FIG. 2 )). When the bus bar 101 is pressed from above until it abuts against the protrusions 108, 109 of the bus bar accommodating section, part of the protrusion 110 is scraped off, and a groove 111 for storing the shavings (cuttings) of the insulating material generated at this time is formed in the bus bar accommodating section at the lower part of the inner part where the protrusion 110 is formed.

[0012] In this embodiment, since the protrusion 108 is also provided on the inner bottom 107 at a position corresponding to the protrusion 110 formed on the inner portion 106 of the busbar accommodating portion, the groove 111 is provided in the region between the protrusion 110 and the inner bottom 107 where the protrusion 108 is provided (see also FIG. 4 ). As shown in FIG. 3 , in one of the busbar accommodating portions, the protrusion 109 that contacts the busbar 101 is provided at a position away from the protrusion 108. Since the protrusion 109 does not have a protrusion 110 that engages with the busbar 101 in the vicinity thereof, the protrusion 110 is not removed when the busbar 101 is press-fitted into the busbar accommodating portion, and therefore, the groove 111 is omitted from the inner bottom. Therefore, in the region of each busbar accommodating portion where the protrusions 110 that contact both sides of the busbar 101 are not provided, the protrusion 109 without the groove 111 may be provided at a position away from the protrusion 108.

[0013] FIG. 5 shows a plan view of the terminal block according to this embodiment as seen from the outer bottom 112 of the holder 102. As shown in this figure, the outer bottom 112 of the holder 102 has a protrusion 113 (third protrusion) provided at a position facing the protrusions 108 and 109 across the bottom of the holder 102 (see also FIG. 6 (the cross-sectional view taken along B-B in FIG. 2)). In other words, when viewed through the bus bar 101 and the holder 102, the protrusion 113 is provided at a position that roughly overlaps the protrusions 108 and 109 in a plan view. As shown in FIG. 5, the protrusions 113 are preferably provided at a number of dispersed positions across the planar area of ​​the outer bottom 112 of the holder 102, and providing the protrusions in at least three or more positions is desirable because it allows the terminal block 100 to be positioned stably when the holder 102 is placed on an assembly jig such as a surface plate. In this embodiment, as shown in the figure, two protrusions 113 are provided at positions that overlap each protrusion in plan view corresponding to protrusions 108 and 109, for a total of four protrusions 113 for each bus bar 101.Even when viewed as a single bus bar 101, three or more protrusions 113 are provided, which effectively prevents the bus bar 101 from being positioned at an angle.

[0014] The number of protrusions 108, 109, 110, and grooves 111 provided in each bus bar accommodating portion of holder 102 can be set arbitrarily. In the present embodiment, the protrusions 108 and 109 that come into contact with bus bar 101 are arranged at two discrete positions so that flatness can be maintained to a certain extent depending on the length of bus bar 101 in the extension direction. However, when a configuration is adopted in which the length of bus bar 101 in the extension direction is further increased, it is desirable to increase the number of protrusions as appropriate, and they may be arranged at three or more positions.

[0015] Returning to Figure 3, the holder 102 is formed with a nut 114 for fastening with a bolt at the position of the connection portion 104 of the bus bar 101, and a nut groove 115 for storing the nut 114 (see also Figure 7 (the CC cross-sectional view of Figure 2)). Note that the shape of the nut 114 illustrated above is square, but is not limited to this. Furthermore, the gap between the nut 114 and the nut groove 115 for storing the nut 114 may be either a gap or no gap. Furthermore, the nut 114 may be directly attached to the bus bar 101 by caulking or the like.

[0016] The terminal block 100 shown in Fig. 1 is formed by assembling the bus bar 101 and nut 114 configured in this manner to the holder 102. The assembling is performed by inserting the nut 114 into the nut groove 115 of the holder 102, placing the bus bar 101 in the bus bar accommodating portion of the holder 102, and grinding and press-fitting the protrusion 110 as described above.

[0017] In this embodiment, as shown in FIG. 8 , the present invention is intended for application to a three-phase AC-driven rotating electric machine 116 that is commonly used as a rotating electric machine 116 constituting a vehicle drive device. Three bus bars 101 are provided corresponding to the three-phase AC power supply, and three corresponding bus bar accommodating portions configured as recesses for accommodating the bus bars 101 are also provided. Each bus bar accommodating portion is formed in a recess shape having an extension direction corresponding to the planar shape of each bus bar 101. Specifically, as shown in FIG. 9 , one end (connection portion 105 side) of the bus bar 101 is connected to a connection plate 117 provided on the rotating electric machine 116, and as shown in FIG. 8 , the other end (connection portion 104 side) is connected to a power supply cable (not shown) from an inverter, which is a control device that controls the rotating electric machine 116, via a power supply line 118, thereby electrically connecting the rotating electric machine 116 and the inverter.

[0018] In the first embodiment, the shape of the connection portion 105 is T-shaped to match the shape of the connection plate 117 of the rotating electric machine 116, but it may be L-shaped, terminal hole-shaped, or any other shape. As shown in Fig. 9, the arrangement of the connection portions 105 is set so that each phase of the bus bar 101 is attached to the annular three-phase connection plate 117, but the position of the connection portions 105 is determined by the phase sequence of the rotating electric machine 116, etc. Furthermore, since the bus bars 101 are connected to the annular three-phase connection plate 117 respectively so as not to interfere with each other in a planar manner, the bus bars 101 all have different planar shapes.

[0019] In this embodiment, as shown in Fig. 1, for example, the bus bar accommodating section includes both a bus bar 101 located at the back of the drawing and extending in a relatively straight line, and a bus bar 101 located at the front of the drawing and extending in two directions generally perpendicular to each other via a bent portion. In the former bus bar accommodating section that holds the bus bar 101 extending in a relatively straight line, as shown in Fig. 3, two protrusions 108 have a rectangular planar shape with their longitudinal direction generally perpendicular to the extension direction of the bus bar 101 and the bus bar accommodating section, and are provided at slightly separated positions. Furthermore, in the latter bus bar accommodating section that accommodates the bus bar 101 extending in two directions via a bent portion, as shown in Fig. 3, the protrusions 108 and 109 have rectangular planar shapes with different longitudinal directions generally perpendicular to the extension directions of the bus bar 101 and the bent portion of the bus bar accommodating section.

[0020] In this way, the protrusions 108 and 109 that come into contact with the bus bar 101 are provided at discrete positions, and the protrusions 108 and 109 are provided in a rectangular planar shape with their longitudinal directions generally perpendicular to the extension direction of the bus bar accommodating portion, thereby enabling the bus bar 101 held in the bus bar accommodating portion to have a high flatness and a stable posture. In particular, even in the case of a bus bar 101 that extends in two directions that are generally perpendicular via a bend, the protrusions 108 and 109 that have their longitudinal directions perpendicular to each extension direction are similarly arranged, thereby enabling the bus bar 101 of that shape to have a stable posture while maintaining a good flatness.

[0021] Although the illustration and description of the terminal block 100 and rotating electric machine 116 shown in the overall diagram in Figure 8 are omitted, they are all housed within the housing of the electric vehicle drive device together with an inverter, which is a control device that drives and controls the rotating electric machine 116, and a gear mechanism that appropriately interfaces with the rotating electric machine, etc., to form the electric vehicle drive device.

[0022] The manufacturing method of the terminal block according to this embodiment will now be summarized. First, the holder 102 and the bracket 103 are integrally molded by insert molding. Next, the holder 102 is placed on an assembly jig such as a surface plate. At this time, the holder 102 is supported by a plurality of protrusions 113 on the outer bottom 112 of the holder 102. If warping occurs in the holder 102 during resin molding, causing variations in the height of the protrusions 113, the resin molding die is corrected by machining the portion of the resin molding die where the protrusions 113 are formed, or by adjusting the position of the portion so that it can be independently adjusted. This allows the height of the protrusions 113 to be adjusted without having to correct the entire outer bottom 112 of the holder 102, allowing the holder 102 to be supported in a stable position.

[0023] Next, to adjust the position of each bus bar 101, the heights of the protrusions 108, 109 formed on the inner bottom 107 of the holder 102 are adjusted. In the same procedure as for the protrusions 113 provided on the outer bottom 112, if variations in the heights of the protrusions 108, 109 are found due to the influence of warping during resin molding, the resin molding die is corrected by machining the portions of the resin molding die where the protrusions 108, 109 are formed, or by adjusting the positions of these portions so that their positions can be adjusted independently. This makes it possible to adjust the heights of the protrusions 108, 109 without correcting the entire area of ​​the inner bottom 107 of the holder 102, and allows the position of the bus bars 101 to be adjusted with high precision.

[0024] The above procedure completes the height adjustment of the protrusion 113 on the outer bottom 112 of the holder 102 and the protrusions 108, 109 on the inner bottom 107 of the bus bar accommodating section, so the holder 102 is then placed on an assembly jig such as a surface plate and is then pressed into place from above the bus bar accommodating section between the protrusions 110 formed at opposing positions on the inner part 106 of the bus bar accommodating section. At this time, the surface of the protrusion 110 is scraped, but as described above, the shavings are stored in the groove 111, and therefore, accumulation on the protrusion 108 formed on the inner bottom 107 is suppressed, preventing the bus bar 101 from tilting and the resulting deterioration in placement accuracy.

[0025] The terminal block 100 and the connection plate 117 completed through the above steps are fixed at the connection portion 105 by TIG welding. In this embodiment, TIG welding is used, but if bolt holes are provided in the connection plate 117, fastening with bolts is also possible. Next, the terminal block 100 and the rotating electric machine 116 are fixed at the bracket 103 by bolting, and the power supply line 118 connected to the inverter and the terminal block are fixed at the connection portion 104 by bolting. As a result, an electrical connection is made between the inverter (not shown) and the rotating electric machine 116 via the terminal block 100, thereby forming the main circuit of the vehicle drive system.

[0026] As described above, terminal block 100 according to the present embodiment includes a plurality of bus bars 101 each having connection portions 104, 105 formed at its end portion for electrically connecting to a device, a bus bar accommodating portion having a recess formed with inner portion 106 and inner bottom portion 107 to accommodate bus bars 101, holder 102 formed from an insulating material, and protrusions 108, 109 (first protrusions) supporting bus bars 101 formed on inner bottom portion 107. Therefore, by adjusting the height of only protrusions 108 and 109, the influence of warping of holder 102 as a whole can be suppressed without adjusting the height of inner bottom portion 107 of holder 102 as a whole, and connection portions 104, 105 provided at both ends of bus bars 101 can be accurately positioned. This reduces initial stress when connected to a device, thereby providing a highly reliable terminal block for use in a vehicle drive system.

[0027] In the terminal block 100 of this embodiment, the protrusions 108, 109 (first protrusions) are formed at two or more locations in the extension direction of the bus bar 101, so that the posture can be stably supported, especially in the case of a bus bar 101 that is long in the extension direction, and the accuracy of the connection part can be improved while making the structure stronger, thereby increasing the reliability of the terminal block.

[0028] The terminal block 100 of this embodiment is provided with a bracket 103 for assembling the holder 102 to an apparatus. Therefore, when assembling this terminal block to an apparatus, the resin holder 102 is prevented from being subjected to stress when the bolts are tightened, and initial stress can be reduced, thereby improving the reliability of the terminal block.

[0029] Terminal block 100 according to this embodiment has protrusions 110 (second protrusions) that abut on both side portions of bus bar 101 and are formed to face each other on both sides of inner portion 106 of the recess. As a result, when bus bar 101 is placed in the bus bar accommodating portion of holder 102, bus bar 101 needs to be positioned based on bracket 103 and connection portion 104 and connection portion 105 of bus bar 101. However, since the protrusions 110 restrict lateral movement of bus bar 101 to serve as a positioning guide and are adjustable in the direction in which bus bar 101 extends, it becomes easier to improve the accuracy of adjusting the position of bus bar 101.

[0030] In the terminal block 100 according to this embodiment, the protrusions 110 (second protrusions) are formed in a shape such that the spacing between opposing protrusions 110 narrows as the protrusions move from the top of the busbar accommodating portion toward the inner bottom 107. Therefore, when the busbar 101 is assembled to the holder 102, the surface of the protrusions 110 is scraped as they are pressed in, and when they finally come into contact with the protrusions 108, 109 (first protrusions) provided on the inner bottom 107, the busbar 101 is sandwiched between the protrusions 110 and fitted together, thereby enabling the busbar 101 to be fixed precisely and stably and preventing it from falling out.

[0031] In the terminal block 100 of this embodiment, a groove portion 111 is formed in the busbar accommodating portion at the lower part of the inner portion 106 where the protrusion 110 (second protrusion) is formed. This prevents shavings of the insulating material that are generated when the busbar 101 is pressed in while scraping the surface of the protrusion 110 from accumulating on the surface of the protrusions 108, 109 (first protrusion) provided on the inner bottom portion 107, thereby preventing the busbar 101 from tilting and the resulting deterioration in the positioning accuracy of the busbar 101.

[0032] In the terminal block 100 according to this embodiment, the outer bottom 112 of the holder 102 is provided with three or more protrusions 113 (third protrusions), and therefore, by simply adjusting the height of the protrusions 113, the posture of the terminal block 100 can be stabilized when the holder 102 is placed on an assembly jig such as a surface plate. This makes it possible to easily improve the accuracy and work efficiency when assembling the bus bar 101.

[0033] In the terminal block 100 according to this embodiment, the protrusion 113 (third protrusion) is positioned opposite the protrusions 108 and 109 (first protrusions). Therefore, when the busbar 101 is pressed between the protrusions 110 while scraping its surface, the force acting on the protrusion 110 can be received from a position exactly opposite it, thereby reducing the stress generated in the resin-molded holder 102.

[0034] The terminal block 100 of this embodiment is made of polyphenylene sulfide, a material that has excellent mechanical strength, chemical resistance, dimensional stability, and electrical insulation properties as the insulating material for the holder 102, and therefore is a particularly advantageous application example in that it ensures insulation between the bus bars 101 and enables improvements in terms of precision and resistance to stress generated inside the terminal block 100.

[0035] The method for manufacturing a terminal block holder according to this embodiment includes a first step of integrally molding a busbar accommodating portion formed with a recess having an inner portion 106 and an inner bottom portion 107 and a holder having protrusions 108, 109 (first protrusions) arranged on inner bottom portion 107, and a second step of adjusting the heights of protrusions 108, 109 by partially adjusting the mold that molds protrusions 108, 109 if holder 102 is deformed in the first step and the heights of protrusions 108, 109 become uneven. This improves the accuracy of the heights of protrusions 108, 109 and the position of bus bar 101 supported by protrusions 108, 109. This reduces initial stress when connected to a device, making it possible to provide a highly reliable terminal block holder for use in a vehicle drive system.

[0036] Furthermore, when the terminal block 100 according to this embodiment is applied to a drive device for an electric vehicle, reliability, including precision, heat resistance, and vibration resistance, of the bus bar 101 and terminal block 100 that connect the rotating electric machine 116 and inverter housed in the housing of the drive device for an electric vehicle is improved, thereby improving the durability of the drive device or the electric vehicle. In particular, in the drive device for an electric vehicle, heat is generated in the rotating electric machine 116, the inverter, and the bus bar 101 held by the terminal block 100 that connects them. Therefore, a drive device that uses the terminal block 100 according to this embodiment has a major feature in that it is advantageous in terms of heat resistance.

[0037] Furthermore, deterioration in the positional accuracy of busbar 101 held by terminal block 100 generates initial stresses such as residual stresses in connection portions 104, 105 between busbar 101 and each device connected thereto. This initial stress, such as residual stress, strongly affects the deterioration of busbar 101 and connection portions 104, 105 in response to external stresses generated by a vibration phase shift between busbar 101 and each device when the electric vehicle and drive unit are operated while mounted on the electric vehicle. Moreover, the electric vehicle will continue to be used in this condition for 10 years or so. In light of this, the configuration of the drive unit employing terminal block 100 according to this embodiment has the advantage of being able to achieve a high level of durability required for a drive unit for an electric vehicle.

[0038] 10 is a plan view of the terminal block 100 according to the second embodiment when a harness is attached, as viewed from the outer bottom 112 of the holder 102. The method of electrical connection to the device mounted on the vehicle is the same as in the first embodiment, but the surface on which the protrusion 113 provided on the outer bottom 112 of the holder 102 is arranged is provided with a harness holding portion 121 that can hold a harness 119, such as a temperature sensor harness, attached to a rotating electrical machine 116 with a cable tie 120 or the like.

[0039] In this way, by providing the harness holding portion 121 on the outer bottom portion 112 of the holder 102, the harness 119 and the harness holding portion 121 do not affect the positional accuracy of the bus bar 101, and the harness 119 can be made less susceptible to the effects of heat generated when current is supplied to the bus bar 101. For example, when applied to the drive device for an electric vehicle described in the first embodiment, the wiring of the main circuit system including the bus bar 101 and the like and the wiring of the measurement control circuit system including the harness 119 and the like can be arranged in separate locations, thereby improving the ease of routing the harness 119 within the housing of the vehicle drive device.

[0040] Although various exemplary embodiments and examples are described in this disclosure, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless variations not illustrated are anticipated within the scope of the technology disclosed in this specification. For example, this includes cases where at least one component is modified, added, or omitted, or where at least one component is extracted and combined with components of another embodiment.

[0041] 100: terminal block, 101: bus bar, 102: holder, 103: bracket, 104, 105: connection portion, 106: inner portion, 107: inner bottom portion, 108, 109, 110: protrusion, 111: groove portion, 112: outer bottom portion, 113: protrusion, 116: rotating electric machine, 119: harness, 121: harness holding portion

Claims

1. A terminal block comprising: a plurality of bus bars each having a connection portion formed at its end for electrically connecting to a device; a bus bar accommodating portion having a recess with an inner portion and an inner bottom formed therein for accommodating the bus bars; a holder formed of an insulating material; and a first protrusion formed on the inner bottom for supporting the bus bars.

2. The terminal block according to claim 1, wherein the first protrusions are formed at two or more locations in the extending direction of the bus bar.

3. The terminal block according to claim 1, further comprising a bracket for attaching the holder to the device.

4. The terminal block according to claim 1, further comprising second protrusions formed on both sides of the inner portion of the recess so as to face each other and abut against both sides of the bus bar.

5. The terminal block according to claim 4, characterized in that the second protrusions are formed in a shape such that the distance between opposing second protrusions narrows as they move from the top of the bus bar accommodating section toward the inner bottom.

6. The terminal block according to claim 5, wherein a groove is formed in the bus bar accommodating portion below the inner portion where the second protrusion is formed.

7. The terminal block according to claim 1, wherein the holder has three or more third protrusions on the outer bottom surface thereof.

8. The terminal block according to claim 7, wherein the third protrusion is disposed at a position opposite to the first protrusion.

9. The terminal block according to any one of claims 1 to 8, wherein the insulating member of the holder is polyphenylene sulfide.

10. The terminal block according to any one of claims 1 to 9, characterized in that the holder has a harness holding portion on the outer bottom for holding the harness.

11. A vehicle drive device comprising: a rotating electric machine; a power conversion device that drives and controls said rotating electric machine; and a terminal block according to any one of claims 1 to 10 that is electrically connected to said rotating electric machine and said power conversion device at the connection portion of said bus bar.

12. A method for manufacturing a terminal block holder made of insulating material, comprising: a first step of integrally molding a holder having a busbar accommodating portion formed with a recess having an inner portion and an inner bottom, and a first protrusion disposed on the inner bottom; and a second step of adjusting the height of the first protrusion by partially adjusting a mold for molding the first protrusion, if the holder is deformed by the first step and the height of the first protrusion becomes uneven.

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