200818636 九、發明說明： 【發明所屬之技術領域】 本發明係關於一種電連接器及其組裝方法；具體而言，本 發明係關於一種應用於低電壓差動訊號傳輸技術(Low Voltage Differential Signing Technology，LVDS)之電連接器。 【先前技術】 隨著電子裝置的發展，在功能及體積上日益強大及小型 化，電連接器也朝向多功、精密及輕薄短小的趨勢發展。鑒於 電連接斋導電端子間之間距設計得越來越小，如何精密組裝電 連接器之各部件，並避免公母端間之電性連接未充分接觸，就 成為了重要的課題。傳統LVDS電連接器係由包含絕緣本體、 殼體、端子與彈片等之零組件組成。藉由現今的技術工藝的提 幵，可直接於金屬鐵殼上沖壓成形複數個彈片，有效地減少了 LVDS電連接器之組成構件。 習知電連接器金屬殼體之成型方式，係將金屬鐵殼沖壓形 成-細長之本體部，除了喻合絕緣本體之^^侧及反向於該前侧 之後侧外’本體部之兩端可圍繞著絕緣本體之外顯，於絕緣 本體之下表祕合。此外，習知電連接器之組裝方法係包括以 預定方向，例如由後向前，逐—將複數個導電端子、金屬殼體 及板狀導電接地部等部件，依序組裝於崎本體中。一般而 言，已有金屬殼體及呈板狀之導電接地部兩者—树壓成形， 除可減少構料，亦可簡化各部件趣緣她礙步驟及社 5 200818636 省工時。 【發明内容】 本發明之主要目的在於提供一種電連接器，具有較高之結 合可靠性。 本發明之主要目的在於提供一種電連接器，可增加電連接 器之組裝效率。 本發明之主要目的在於提供一種電連接器之金屬鐵殼，具 有較強的結構。 本發明之另一目的在於提供一種電連接器，具有較節省的 組裝工時。 本發明之電連接器包含複數個導電端子、絕緣本體及金屬 设體。導電端子係以導電材料製成並用以傳送電氣信號；金屬 殼體具有上壁、下壁、二侧壁及分別連接上壁及下壁底端之至 少連接部。金屬殼體之上壁係連接有中間部，延伸自上壁並 彎折於金屬殼體内’·絕緣本體由絕緣塑膠製成，具有第一排插 槽及第二排插槽。第一排插槽供與複數個導電端子插接，第二 排插槽供射間赖接，使絕緣本贿置於金屬殼體中。 本發明電連接器之金屬鐵殼包含上壁、下壁、二側壁以及 了_相_±壁，上壁包含連接—延 折於該金屬殼_之中辦卜每—趣係分別遮紅壁及下辟 之侧邊，分別連接上壁及下壁之底端。在較佳實_中，^ 部進-步包含概财m卡封_係成形有卡 合部，連接部之侧邊另包含連接定位片，係延伸並彎折於該金 200818636 屬殼體；每一侧壁之一端係延伸自上壁之一侧，側壁之另一端 則與下侧壁之侧邊相對應。 在較佳實施例中，本發明電連接器之組裝步驟，包含成形 一絕緣本體。絕緣本體較佳具有前端、後端、第一排插槽及第 二排插槽。組裝金屬殼體，金屬殼體之上壁包含形成複數個卡 合部’每一^^合部較佳係朝金屬殼體内彎折並可從前端插接於 第二排插槽。組裝複數個導電端子，每一導電端子係可從後端 插接於第一排插槽。換言之，本發明之電連接器之組裝步驟係 可將金屬殼體及導電端子分別從絕緣本體之前端及後端組 裴，甚至可將金屬殼體及導電端子同時組裝於絕緣本體中，以 節省組裝工時。 【實施方式】 本發明長：供一種電連接器，較佳係應用於低電壓差動訊號 傳輸技術(Low Voltage Differential Signing Technology, LVDS) 之母端電連接器，並供與相應之公端電連接配合使用。本發明 之電連接器較佳係應用於如筆記型電腦、桌上型電腦、行車電 腦或其他相類似之電子裝置與產品。然而在不同實施例中，本 發明之電連接ϋ亦可細於如手機、掌上型電腦或是其他行動 影音裝置。 如圖la至圖5所示，電連接器包含複數個導電端子2〇〇、 絕緣本體300及金屬_4〇〇。如圖u及圖化所示，導電端 子2〇0係以導電材料製成並供印刷電路板(圖未繪示)連接以傳 送電氣信號。金触體4GG具有上壁·、下壁、二側壁 200818636 430及分別連接上壁410及下壁420底端之至少一連接部 440。如圖2a及圖2b所示，每一側壁430之一端係延伸自上 壁410之一側，侧壁430之另一端則與下壁42〇之側邊相對 應。然而在不同實施例中，每一侧壁430之一端亦可延伸自下 壁420之一侧，側壁430之另一端則與上壁41()之侧邊相對 應。此處所言之側壁430與下壁420之侧邊相對應，係指每一 侧壁430係分別遮蔽上壁41〇及下壁420之側邊。在如圖2a 及圖2b所示之實施例中，金屬殼體4〇〇較佳係以沖壓彎折成 形矩形框體，而與絕緣本體3〇〇接合。 如圖2a之實施例所示，金屬殼體4〇〇較佳係設置有成對之 連接部440。然而在不同實施例中，亦可設置單一之連接部 440。連接部440係分別設置於鄰近侧壁43〇之位置，並與侧 壁430保持間隙442，且連接部44〇係分別連接上壁41〇及下 壁420之底端。此外，定位片441係延伸自連接部44〇之一側 邊f折並成形於金屬殼體4〇〇内。然而在不同實施例中，定 位片441亦可自侧壁43〇之前端延伸，彎折並成形於金屬殼體 内。在如圖2a及圖2b所示之實施例中，定位片441較佳 係包3 ,又置有孔洞4411，供與相應配接之公端連接器(圖未繪 示)卡合定位。 人又在如圖2a及圖2b所示之實施例中，上壁41〇進一步包 3有中間部450,中間部450係延伸並彎折於金屬殼體4〇〇内。 中間部450更包含成形有複數個卡合片451，每一卡合片451 兩側係成形有卡合部453，供與絕緣本體3〇〇之第二插槽32〇 8 200818636 卡δ (如圖la及lb)。每一·^合片451中進一步具有至少一彈 片452，供與相應插接之公端電連接器(圖未繪示)電性連接。 在如圖2b所示之較佳實施例中，每一卡合片451之彈片452 數里較佳係設置成對之彈片452。當彈片之452之數量越多 時’相對與公端電連接器之接合性更佳；反之，當彈片452之 數量越少時，相對與公端電連接關之接合性較低。然而在其 它不同的實施例中，亦可選擇性地設置不同數量的彈片452於 每一卡合片451中。 金屬殼體400之下殼420 -側邊緣進一步形成有複數個卡 合部470，供與絕緣本體3〇〇插接嵌合，以增加金屬殼體4〇〇 定位於絕緣本體300之效果。為了確保定位之效果，在每一^^ 合部470兩侧，較佳係分別設置至少一倒刺部471。此外，金 屬殼體400下壁420之另一侧及兩側較佳係設置複數個接點部 460。上述接點部460主要係供與相應之印刷電路板(圖未繪示） 接地以防止電磁干擾(EMI，Electromagnetic Interference)，並使 本發明具有定位於此印刷電路板之功用。然而在其它不同的實 施例中，亦可在下壁420周緣均設置接點部460，以增加定位 之效果。 如圖3a及圖3b所示，為本發明之金屬殼體另一較佳實施 例圖。在此所言之實施例與上述實施例之不同處，在於從上壁 410所彎折成形之中間部450，係分別單獨成形出複數個卡合 片451。其中，每一^^合片451中進一步具有至少一彈片452。 在如圖3b所示之實施例中，較佳係設置成對之彈片452。此 200818636 外’每一卡合片451兩側均間隔有間隙扮。間隙453係分別 位於兩卡合片4S1間之空間，供與絕緣本體嵌合。基此， 在本實施例中，由於中間部45〇單獨成形之卡合部451面積較 小，在與絕緣本體3GG插鱗，使絕緣本體具有相對較小 之損害度。換言之，絕緣本體3〇〇之強度較強。 在如圖3b所示之較佳實施例中，$ 了增加與絕緣本體3〇〇 之嵌合效果，卡合部451兩侧較佳係分設至少一倒刺部4分。 然而在其它不同的實施例中，亦可在卡合部451之每一侧邊設 置複數個倒刺部455。其它結構同上所述，在此不吝贅述。 如圖4及圖5所示，絕緣本體3〇〇由絕緣塑膠、橡膠或其 它絕緣材料所製成。絕緣本體3〇〇具有第一排插槽31〇及第二 排插槽320。第一排插槽310供與複數個導電端子2〇〇插接， 第二排插槽320供與中間部450之卡合部451插接，以使絕緣 本體300定位於金屬殼體4〇〇中。在如圖4所示之較佳實施例 中，絕緣本體300較佳更包含第三排插槽33〇，供與金屬殼體 400之下壁420插接，用以增加定位金屬殼體4〇〇於絕緣本體 300之效果。 以下進一步說明本發明之電連接器組裝方法，包含下列步 驟：成形絕緣本體300,絕緣本體300包含前端340、後端350、 第一排插槽310及第二排插槽320。組裝金屬殼體400，金屬 殼體400之上壁41〇包含形成複數個卡合部453，每一^^合部 453係朝金屬殼體4〇〇内彎折並可從前端34〇插接於第二排插 槽320。組裝複數個導電端子200，每一導電端子2〇〇係可從 200818636 後端350插接於第一排插槽310。在如圖5所示之較佳實施例 中，組裝金屬殼體400於絕緣本體300時，可與組裝複數個導 電端子200同時進行。然而在不同實施例中，組裝複數個導電 端子200步驟亦可優先組裝金屬殼體4〇〇，或組裝金屬殼體4⑻ 之步驟亦可優先組裝複數個導電端子2〇〇之步驟進行。其中， 母一^^合部451插接於第二排插槽320時，卡合部451係分別 從上壁410之中間部450所彎折延伸而成。又組裝金屬殼體 400於絕緣本體3〇〇時，金屬殼體4〇〇之下壁420進一步包含 成形複數個卡合部470，用以插接絕緣本體3〇〇成形之第三排 插槽330。 如圖5所示，以沖壓方式形成金屬殼體4〇〇後，可將金屬 殼體400彎折形成矩形框體。如圖2a所示，金屬殼體4〇〇較 佳係以兩連接部440所夾持之平面，作為彎折金屬殼體4〇〇之 基準面。如圖2a之較佳實施例所示，金屬殼體4〇〇之上部朝 向基準面之背侧垂直彎折約90度角形成上壁41〇 ;金屬殼體 400上部之一延長前端，則朝基準面之背侧彎折約90度角形 成平行於上壁410之中間部450，且中間部450係垂直於基準 面。金屬忒體400上部之二延長侧端，則朝上壁4〇〇底侧之方 向’垂直彎折約90度角形成健430。金屬殼體4〇〇之下部 亦朝向基準面之背侧垂直彎折約9〇度角形成下壁樣及矩形 框體。 、本發明已由上述相關實施例加以描述，然而上述實施例僅 為實知本發明之範例。必需指出的是，已揭露之實施例並未限 200818636 制本發明之範圍。相反地，包含於申請專利範圍之精神及範圍 之修改及均等設置均包含於本發明之範圍内。 【圖式簡單說明】 圖la為本發明電連接器之立體正視圖； 圖lb為本發明電連接器之立體背視圖； 圖2a為本發明金屬殼體之立體正視圖； 圖2b為本發明金屬殼體之立體背視圖； 圖3a為本發明金屬殼體另一實施例之立體正視圖； 圖3b為本發明金屬殼體另一實施例之立體背視圖； 圖4為本發明電連接器之剖視圖； 圖5為本發明電連接器之元件爆炸示意圖。 【主要元件符號說明】 200導電端子 300絕緣本體 310第一排插槽 320第二排插槽 330第三排插槽 340前端 350後端 400金屬殼體 410上壁 12 200818636 420下壁 430側壁 440至少一連接部 441定位片 4411孔洞 442、453 間隙 450中間部 451卡合片 452彈片 455、471倒刺部 460接點部 470下壁卡合部200818636 IX. INSTRUCTIONS: [Technical Field] The present invention relates to an electrical connector and an assembly method thereof; in particular, the present invention relates to a low voltage differential signaling technology (Low Voltage Differential Signing Technology) , LVDS) electrical connector. [Prior Art] With the development of electronic devices, functions and volumes are becoming increasingly powerful and miniaturized, and electrical connectors are also moving toward multi-function, precision, and lightness and thinness. In view of the fact that the distance between the conductive terminals of the electrical connection is getting smaller and smaller, how to accurately assemble the components of the electrical connector and avoid the electrical connection between the male and female ends is not sufficiently contacted, which becomes an important issue. A conventional LVDS electrical connector is composed of a component including an insulative housing, a housing, a terminal, and a shrapnel. Through the improvement of the current technical process, a plurality of shrapnel can be formed directly on the metal iron shell, which effectively reduces the components of the LVDS electrical connector. The metal housing of the conventional electrical connector is formed by stamping a metal iron shell into an elongated body portion, except for the side of the insulating body and the opposite sides of the front side. It can be displayed around the insulating body and is hidden under the insulating body. In addition, the conventional electrical connector assembly method includes sequentially assembling a plurality of conductive terminals, a metal case, and a plate-shaped conductive ground portion in a predetermined direction, for example, from the front to the front, in a plurality of components. In general, there are both metal casings and plate-like conductive grounding parts - tree forming, which can reduce the number of materials and simplify the various parts of the process. SUMMARY OF THE INVENTION A primary object of the present invention is to provide an electrical connector that has a high degree of joint reliability. SUMMARY OF THE INVENTION A primary object of the present invention is to provide an electrical connector that increases the assembly efficiency of the electrical connector. SUMMARY OF THE INVENTION A primary object of the present invention is to provide a metal iron casing of an electrical connector having a strong structure. Another object of the present invention is to provide an electrical connector that has a relatively reduced assembly man-hour. The electrical connector of the present invention includes a plurality of conductive terminals, an insulative housing, and a metal body. The conductive terminal is made of a conductive material and is used to transmit an electrical signal; the metal housing has an upper wall, a lower wall, two side walls, and at least a connecting portion connecting the upper wall and the bottom end of the lower wall, respectively. The upper wall of the metal casing is connected with an intermediate portion extending from the upper wall and bent into the metal casing. The insulating body is made of insulating plastic and has a first row of slots and a second row of slots. The first row of slots are for mating with a plurality of conductive terminals, and the second row of slots are for splicing, so that the insulating bribe is placed in the metal casing. The metal iron shell of the electrical connector of the present invention comprises an upper wall, a lower wall, two side walls and a _phase_±wall, and the upper wall comprises a connection-extending in the metal shell _ The sides of the lower side are connected to the bottom ends of the upper and lower walls, respectively. In the preferred embodiment, the step further comprises a m-cap seal, and the side portion of the connecting portion further comprises a connecting positioning piece extending and bent in the gold 200818636 genus housing; One end of each side wall extends from one side of the upper wall, and the other end of the side wall corresponds to a side of the lower side wall. In a preferred embodiment, the assembly of the electrical connector of the present invention includes forming an insulative body. The insulative housing preferably has a front end, a rear end, a first row of slots and a second row of slots. The metal housing is assembled, and the upper wall of the metal housing includes a plurality of engaging portions. Each of the mounting portions is preferably bent into the metal housing and can be inserted into the second row of slots from the front end. A plurality of conductive terminals are assembled, and each of the conductive terminals can be inserted into the first row of slots from the rear end. In other words, the assembly step of the electrical connector of the present invention can form the metal housing and the conductive terminals from the front end and the rear end of the insulating body, respectively, and even assemble the metal housing and the conductive terminals into the insulating body at the same time, thereby saving Assembly work hours. [Embodiment] The present invention provides an electrical connector, preferably applied to a female electrical connector of a Low Voltage Differential Signing Technology (LVDS), and is provided with a corresponding male terminal. Use in conjunction with the connection. The electrical connector of the present invention is preferably applied to, for example, a notebook computer, a desktop computer, a traveling computer or other similar electronic devices and products. However, in various embodiments, the electrical port of the present invention can also be thinner than, for example, a cell phone, a palmtop computer, or other mobile audiovisual device. As shown in FIG. 1 to FIG. 5, the electrical connector includes a plurality of conductive terminals 2 〇〇, an insulating body 300, and a metal _4 〇〇. As shown in Figure u and the figure, the conductive terminals 2〇0 are made of a conductive material and are connected by a printed circuit board (not shown) for transmitting electrical signals. The gold contact body 4GG has an upper wall, a lower wall, and two side walls 200818636 430 and at least one connecting portion 440 that connects the upper wall 410 and the bottom end of the lower wall 420, respectively. As shown in Figures 2a and 2b, one end of each side wall 430 extends from one side of the upper wall 410, and the other end of the side wall 430 corresponds to the side of the lower wall 42. However, in various embodiments, one end of each side wall 430 can also extend from one side of the lower wall 420, and the other end of the side wall 430 corresponds to the side of the upper wall 41 (). The side wall 430 referred to herein corresponds to the side of the lower wall 420, and means that each side wall 430 shields the side edges of the upper wall 41 and the lower wall 420, respectively. In the embodiment shown in Figures 2a and 2b, the metal housing 4 is preferably formed by stamping and bending a rectangular frame into engagement with the insulative housing 3. As shown in the embodiment of Fig. 2a, the metal housing 4 is preferably provided with a pair of connecting portions 440. However, in various embodiments, a single connection 440 can also be provided. The connecting portions 440 are respectively disposed adjacent to the side walls 43A and maintain a gap 442 with the side walls 430, and the connecting portions 44 are respectively connected to the bottom ends of the upper wall 41 and the lower wall 420. Further, the positioning piece 441 is extended from one side of the connecting portion 44 to be folded and formed in the metal casing 4''. However, in various embodiments, the positioning tab 441 can also extend from the front end of the side wall 43 and be bent and formed into the metal housing. In the embodiment shown in Figures 2a and 2b, the positioning piece 441 is preferably a tie bag 3, and is provided with a hole 4411 for engaging and positioning with a corresponding mating male connector (not shown). In the embodiment shown in Figures 2a and 2b, the upper wall 41 further has an intermediate portion 450 which extends and is bent into the metal casing 4b. The intermediate portion 450 further includes a plurality of engaging pieces 451 formed on each side, and the engaging portions 453 are formed on both sides of the engaging piece 451 for the second slot 32〇8 200818636 of the insulating body 3 (eg, Figures la and lb). Each of the slabs 451 further has at least one elastic piece 452 for electrically connecting to a corresponding male electrical connector (not shown). In the preferred embodiment shown in FIG. 2b, the number of the elastic pieces 452 of each of the engaging pieces 451 is preferably set to be the pair of elastic pieces 452. When the number of the elastic pieces 452 is larger, the engagement with the male electrical connector is better. On the contrary, when the number of the elastic pieces 452 is smaller, the electrical connection with respect to the male electrical connection is lower. However, in other different embodiments, a different number of springs 452 may alternatively be provided in each of the engaging tabs 451. The lower side of the lower casing 420 of the metal casing 400 is further formed with a plurality of engaging portions 470 for inserting and fitting with the insulating body 3 to increase the effect of the metal casing 4 being positioned on the insulating body 300. In order to ensure the positioning effect, at least one barb portion 471 is preferably provided on each side of each of the fitting portions 470. In addition, a plurality of contact portions 460 are preferably disposed on the other side and both sides of the lower wall 420 of the metal casing 400. The contact portion 460 is mainly grounded to a corresponding printed circuit board (not shown) to prevent electromagnetic interference (EMI), and the present invention has the function of positioning the printed circuit board. However, in other different embodiments, the contact portion 460 may be provided on the periphery of the lower wall 420 to increase the positioning effect. 3a and 3b are views showing another preferred embodiment of the metal casing of the present invention. The difference between the embodiment described herein and the above embodiment is that a plurality of engaging pieces 451 are separately formed from the intermediate portion 450 which is bent and formed by the upper wall 410. Each of the slabs 451 further has at least one elastic piece 452. In the embodiment shown in Figure 3b, the springs 452 are preferably disposed in pairs. This 200818636 outer 'each card 451 is spaced on both sides with a gap. The gap 453 is located in a space between the two engaging pieces 4S1 for fitting with the insulating body. Therefore, in the present embodiment, since the intermediate portion 45 is formed with a small area of the engaging portion 451 which is separately formed, the insulating body 3G is inserted into the scale to make the insulating body have a relatively small degree of damage. In other words, the strength of the insulating body 3 is strong. In the preferred embodiment shown in FIG. 3b, the fitting effect of the insulating body 3 is increased, and the two sides of the engaging portion 451 are preferably provided with at least one barb portion. However, in other different embodiments, a plurality of barbs 455 may be provided on each side of the engaging portion 451. Other structures are the same as described above, and are not described herein. As shown in Figures 4 and 5, the insulative housing 3 is made of insulating plastic, rubber or other insulating material. The insulative housing 3 has a first row of slots 31 and a second row of slots 320. The first row of slots 310 are inserted into the plurality of conductive terminals 2, and the second row of slots 320 are inserted into the engaging portions 451 of the intermediate portion 450 to position the insulative housing 300 in the metal housing 4〇〇. in. In the preferred embodiment shown in FIG. 4, the insulative housing 300 preferably further includes a third row of slots 33A for insertion with the lower wall 420 of the metal housing 400 for adding the positioning metal housing. The effect of the insulating body 300. The electrical connector assembly method of the present invention is further described below, and includes the following steps: forming an insulative housing 300 including a front end 340, a rear end 350, a first row of slots 310, and a second row of slots 320. The metal housing 400 is assembled. The upper surface 41 of the metal housing 400 includes a plurality of engaging portions 453. Each of the fastening portions 453 is bent into the metal housing 4 and can be inserted from the front end 34. In the second row of slots 320. A plurality of conductive terminals 200 are assembled, and each of the conductive terminals 2 can be plugged into the first row of slots 310 from the rear end 350 of the 200818636. In the preferred embodiment shown in FIG. 5, the assembly of the metal housing 400 to the insulative housing 300 can be performed simultaneously with the assembly of the plurality of conductive terminals 200. However, in various embodiments, the step of assembling the plurality of conductive terminals 200 may also preferentially assemble the metal case 4, or the step of assembling the metal case 4 (8) may also be performed by preferentially assembling the plurality of conductive terminals 2'. When the female unit 451 is inserted into the second row of slots 320, the engaging portions 451 are respectively bent and extended from the intermediate portion 450 of the upper wall 410. When the metal housing 400 is assembled to the insulative housing 3, the lower surface 420 of the metal housing 4 further includes a plurality of engaging portions 470 for inserting the third row of slots formed by the insulating body 3 330. As shown in Fig. 5, after the metal casing 4 is formed by press forming, the metal casing 400 can be bent to form a rectangular frame. As shown in Fig. 2a, the metal casing 4 is preferably a plane sandwiched by the two connecting portions 440 as a reference surface for bending the metal casing 4''. As shown in the preferred embodiment of FIG. 2a, the upper portion of the metal casing 4 is bent perpendicularly toward the back side of the reference surface by an angle of about 90 degrees to form the upper wall 41A; and one of the upper portions of the metal casing 400 is extended toward the front end. The back side of the reference plane is bent at an angle of about 90 degrees to form an intermediate portion 450 parallel to the upper wall 410, and the intermediate portion 450 is perpendicular to the reference plane. The second side of the upper portion of the metal body 400 is extended to the side end, and the direction of the bottom side of the upper wall 4 is 'a vertical bend of about 90 degrees to form a health 430. The lower portion of the metal casing 4 is also bent perpendicularly toward the back side of the reference surface by about 9 degrees to form a lower wall and a rectangular frame. The present invention has been described by the above-described related embodiments, but the above embodiments are merely examples of the present invention. It must be noted that the disclosed embodiments are not limited to the scope of the invention as set forth in 200818636. On the contrary, modifications and equivalents of the spirit and scope of the invention are included in the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1b is a perspective front view of an electrical connector of the present invention; FIG. 2b is a perspective rear view of the electrical connector of the present invention; FIG. 2a is a perspective front view of the metal casing of the present invention; 3a is a perspective view of another embodiment of the metal casing of the present invention; FIG. 3b is a perspective view of another embodiment of the metal casing of the present invention; FIG. 4 is an electrical connector of the present invention; Figure 5 is a schematic view showing the explosion of the components of the electrical connector of the present invention. [Main component symbol description] 200 conductive terminal 300 insulating body 310 first row slot 320 second row slot 330 third row slot 340 front end 350 rear end 400 metal housing 410 upper wall 12 200818636 420 lower wall 430 side wall 440 At least one connecting portion 441 positioning piece 4411 hole 442, 453 gap 450 intermediate portion 451 engaging piece 452 elastic piece 455, 471 barb portion 460 contact portion 470 lower wall engaging portion