200408764 (1) ·. 玖、發明說明 【發明所屬之技術領域】 本發明是關於內燃機的起動馬達的安裝構造，特別是 關於作成：使起動馬達與曲軸的配設位置接近，讓上述起 動馬達的旋轉軸與上述曲軸的雙軸間距離變短，的這種方 式的上述內燃機的起動馬達的安裝構造。 【先前技術】 φ 以往的內燃機的起動馬達的安裝，相對於該內燃機的 曲軸箱的外殼部所描繪出的外型線，以位於該外型線的外 側的關係來進行安裝，上述起動馬達是被配設在距離曲軸 較遠的位置，讓該起動馬達的旋轉軸與上述曲軸的兩軸間 的距離增加，則從上述起動馬達朝向曲軸的旋轉驅動力的 傳達實質上是經由複數的中間軸來進行（例如，參照專利 文獻1 )。200408764 (1) 玖. Description of the invention [Technical field to which the invention belongs] The present invention relates to a mounting structure for a starter motor of an internal combustion engine, and more particularly, to a method for making the position of the starter motor and the crankshaft close to each other, The mounting structure of the starter motor of the internal combustion engine in such a manner that the distance between the double shafts of the rotating shaft and the crankshaft becomes shorter. [Prior art] φ The installation of a starter motor of a conventional internal combustion engine is installed in a relationship outside the contour line with respect to the contour line drawn on the outer casing of the crankcase of the internal combustion engine. If the distance between the crankshaft of the starter motor and the two shafts of the crankshaft is increased, the transmission of the rotational driving force from the starter motor to the crankshaft is transmitted via a plurality of intermediate shafts. (For example, refer to Patent Document 1).
【專利文獻1】 曰本特開平7 — 208 1 4 1號公報（第3頁，第！圖及第 2圖） 【發明內容】 〔發明欲解決的課題〕 在上述專利文獻1所記載的以往的起動馬達的安裝動 作，如第5圖及第6圖所圖示，該起動馬達〇2相對於內 -4 - (2) (2)200408764 燃機的曲軸箱0 1，相對於該曲軸箱ο 1的側面來看的該箱 體0〗的外殼部所描繪的外型線，是配設成，位於該外型 線的外側（參照第5圖）。 上述起動馬達02與曲軸05是被配設在互相分離的位 置，該起動馬達0 2的旋轉軸0 2 d與上述曲軸〇 5的兩軸部 間距離很大，由上述起動馬達0 2朝向上述曲軸〇 5的旋轉 驅動力的齒輪傳達，是從與上述起動馬達02的旋轉軸 0 2 d —體的齒輪〇 2 e開始，經由：中間軸〇 4 1的齒輪〇 3 , 、中間軸Oh的齒輪〇32、曲軸05的齒輪05!，該驅動力 的傳達是經由中間軸04 !、042來進行的（參照第6圖） 〇 如上述，關於上述以往的內燃機的起動馬達的安裝構 造，該起動馬達的主體構造部的大部分或主體構造部的全 體，是位於曲軸箱的側面（與曲軸垂直相交的面部）來看 的該曲軸箱所描繪的外型線的外側，是成爲這樣的配設關 係，曲軸與上述起動馬達的位置是分離的，該起動馬達的 旋轉軸與上述曲軸間的距離較大，從上述起動馬達朝向上 述曲軸的上述旋轉驅動力的傳達，在利用齒輪來傳達的情 況是經由複數支的中間軸，是作成至少經由兩支中間軸。 經由上述複數支中間軸的上述旋轉驅動力的齒輪傳達 ，不只會導致其動力傳達機構的複雜化，也會導致增加齒 輪等的零件數量，而讓機構大型化，並且，上述旋轉驅動 力的傳達效率也會增加。 (3) (3)200408764 在上述的狀況中，需要著眼於上述內燃機的起動馬達 的女裝構造的改良’特別是關於從該起動馬達朝向上述曲 軸的上述旋轉驅動力的傳達機構的簡化、關於其傳達效率 的提昇、以及減少零件數量讓成本減低等等的改良構造。 〔用以解決課題的手段以及發明的效果〕 本發明，是關於用來解決上述課題的內燃機的起動馬 達的安裝構造的改良，藉由將該起動馬達的安裝儘可能地 接近配設於曲軸，使該起動馬達的旋轉軸與上述曲軸間的 軸間距離縮短，讓從上述起動馬達朝向上述曲軸的旋轉驅 動力的傳達機構簡化之起動馬達的安裝構造， 是具有：起動馬達、曲軸、設置在該曲軸的其中一側 的被動齒輪、設置在該曲軸的另一側的初始傳動齒輪、以 及用來將起動馬達的旋轉驅動力傳達到上述被動齒輪的起 動馬達的齒輪與中間園輪之起動馬達的安裝構造，其特徵 爲：在曲軸箱內，具有：收容著用來將來自於上述起動馬 達的旋轉驅動力傳達到曲軸的上述中間齒輪與上述被動齒 輪的收容部、以及收容著與上述初始傳動齒輪嚙合的初始 從動齒輪的收容部，在對應於兩收容部所夾著的空間區域 的上述曲軸箱上部的外殻部上形成凹部，在該凹部收容著 上述起動馬達，並且在該起動馬達的收容狀態，用來安裝 上述起動馬達的安裝轂部是被設置在對應於收容著上述初 始從動齒輪的上述收容部的曲軸箱上部的外殼部上。 第1發明，是在曲軸箱內，具有：收容著用來將來自 冬 (4) (4)200408764 於上述起動馬達的旋轉驅動力傳達到曲軸的上述中間齒輪 與上述被動齒輪的收容部、以及收容著與上述初始傳動齒 輪嚙合的初始從動齒輪的收容部，在對應於兩收容部所夾 著的空間區域的上述曲軸箱上部的外殼部上形成凹部，在 該凹部收容著上述起動馬達，並且在該起動馬達的收容狀 態，用來安裝上述起動馬達的安裝轂部是被設置在對應於 收容著上述初始從動齒輪的上述收容部的曲軸箱上部的外 殼部上； _ 讓起動馬達與曲軸的配設位置接近，而能大幅度地縮 短起動馬達的旋轉軸與曲軸的軸間距離，當旋轉驅動力從 該起動馬達的旋轉軸傳達到曲軸時，不是像以往的經由複 數支中間軸的方式，而是讓上述旋轉驅動力的傳達經由一 支中間軸來進行，所以可讓用來傳達旋轉驅動力的構造簡 化’減少用來傳達驅動力的零件數量，並且也減少了該旋 轉驅動力在齒輪傳達時所造成的耗損。 第2發明，用來在收容狀態將上述起動馬達安裝在上 g、 述凹部的上述安裝轂部，爲了進行上述起動馬達的安裝， 是設置了 一對在上述曲軸箱上部的外殼部上的位置，以適 合用來收容固定一對安裝用臂部的前端部附近，該一對安 裝用臂部是延伸成：從上述起動馬達的後部的端部或該端 ' 部附近略八字型地擴張， 上述起動馬達是以重心較低且穩定的狀態被收容在上 述凹部’且確實且堅固地被支承著，而由於上述一對安裝 用臂部是呈現八字型，所以對於上述起動馬達起動時的旋 -7- (5) (5)200408764 轉扭矩的變動的支承力很強，能夠對應於該旋轉扭矩的變 化’而可確保該馬達的安裝狀態。 【實施方式】 以下根據第1圖〜第4圖來說明本發明的實施方式。 第1圖是顯示沿著內燃機的曲軸箱1的曲軸（沒有圖 示）的方向的一縱剖面圖，在該第丨圖是圖示著曲軸箱1 的部分構造，在該圖面是記載著本發明的特徵構造也就是 起動馬達2與其周邊構造部。 而顯示了中間齒輪3，該中間齒輪3是與齒輪2e嚙 合’齒輪2 e則是與上述起動馬達2的旋轉軸2 d爲一體， 該中間齒輪3藉由與設置在沒有圖示的曲軸6的其中一側 的被動齒輪5嚙合，來讓上述起動馬達2的旋轉驅動力經 由上述中間齒輪3傳達到上述曲軸6 (參照第2圖）。 上述中間齒輪3，是具有大直徑齒輪部3 a與小直徑 齒輪部3 b的兩個齒輪部的構造的齒輪，該中間齒輪3的 大直徑齒輪部3 a是做成與上述起動馬達2的旋轉軸2(1爲 一體而與上述齒輪2e嚙合，且具備有該中間齒輪3的小 直徑齒輪部3 b與設置在上述曲軸6的其中一側的上述被 動齒輪5嚙合（參照第2圖）的構造，經由該齒輪5的嚙 合來讓上述起動馬達2的旋轉驅動力傳達到上述曲軸6。 相對於傳達來自於上述起動馬達2的旋轉驅動力的曲 軸6的其中一側，在該曲軸6的另一側，是設置了沒有圖 示的初始傳動齒輪，該初始傳動齒輪是與初始從動齒輪7 (6) (6)200408764 嚙合著。 在第1圖〜第3圖，8是離合器，9是變速機構，1〇 是正時鏈條，1 1是氣缸體。 上述曲軸箱1 ’在其上部的外殼上是具備有用來安裝 起動馬達2的構造部，該構造部具有由凹部1 a所構成的 構造，該凹部1 a，在第1圖的圖示中，是被形成在：作 爲使上述起動馬達2的旋轉軸2 d的旋轉驅動力傳達到上 述曲軸6的上述中間齒輪3與上述被動齒輪5的收容部也 就是上述曲軸6其中一側的曲軸箱內空間區域、以及上述 初始傳動齒輪與上述初始從動齒輪7的嚙合的該齒輪的收 容部也就是上述曲軸6另一側的上述曲軸箱內空間區域所 夾著的該曲軸箱內空間所對應的該箱體1的上述上部的外 殼部上。 用來安裝上述起動馬達2的上述凹部1 a，其剖面形 狀是做成略筒狀的較淺的圓弧狀（參照第3圖），其長軸 方向是以上述筒狀延伸預定長度的構造，在該凹部1 a是 以第1圖〜第3圖所圖示的狀態配設著上述起動馬達2。 上述起動馬達2的上述配設動作’是藉由將該起動馬 達2的配設狀態的其下方部收容在上述凹部1 a所進行的 ，藉此讓該起動馬達2對上述凹部1 a的配設狀態，上述 起動馬達2距離上述曲軸箱1的外殼部所描繪的外型線的 突出量是被抑制了相當程度。 上述起動馬達2對上述凹部1 a的配設狀態，該起動 馬達2，其前部旋轉軸2 d側是藉由以開孔部1 e所構成的 -9- (7) (7)200408764 環狀支承部1 d所支承，開孔部1 e是設置成從上述曲軸箱 1上部外殼部突出，其後物2 b則是經由從該起動馬達2 的後部2b朝斜後方延伸的一對安裝用臂部2f、2g而被安 裝固定在從上述曲軸箱1外殼部突出預定量的安裝轂部 lb、 1b ° 上述起動馬達2前部的利用上述環狀支承部1 d所進 行的支承，更具體來看，是藉由將上述起動馬達2的殻體 部前方突出部2 a，經由環狀的彈性構件2 c (例如0型環 )，嵌合支承在上述曲軸箱1的上述上部外殼部上的凹部 1 a長軸方向上的設置在其中一側形成端的環狀的開孔部 1 e，的這種方式來進行的。 利用該開孔部1 e所進行的上述馬達殼體前方突出部 2a的嵌合支承，實質上該開孔部1 e的中心是與上述起動 馬達2的旋轉軸2d的中心一致，而從該關係可推導出上 述開孔部1 e的中心是大致與馬達2的長軸方向中心一致 的關係。 上述起動馬達2後部2b的經由上述一對的安裝用臂 部2f、2g的該馬達2的支承，更具體來說，是經由上述 曲軸箱1的上述上部外殼上的凹部1 a長軸方向上的設置 在另一側形成端的兩個突出相當程度的安裝轂部1 b、1 b 來進行的（參照第4圖）。 從上述起動馬達2的後部2b朝向斜後方延伸的上述 一對的安裝用臂部2f、2 g的個別前端部，是分別使用螺 栓]c等而被固定在上述兩個安裝轂部lb、lb的上部，該 -10 - (8) (8)200408764 兩個安裝轂部1 b、1 b，從第1圖可以看出，是被設置在 略對應於上述曲軸箱2內的上述初始傳動齒輪7的上部的 該曲軸箱1上部的外殼部上的位置。 從上述起動馬達2後部2 b延伸的上述一對安裝用臂 部2f、2g，如第4圖放大圖示，是從上述起動馬達2的 後部2b朝向斜後方呈略八字型地延伸，該一對安裝用臂 部2 f、2 g的上述八字型的從上述馬達2後部2 b朝向斜後 方的延伸，如第3圖及第4圖所圖示，是由於在右側的安 裝用臂部2 f側有热缸體1 1 ’而是一'種妥協性的設計。 也就是說，因爲上述氣缸體11的存在，所以上述右 側的安裝用臂部2f相對於上述馬達2的長軸方向無法朝 向直角方向延伸，另一方面，而爲了要抵抗上述起動馬達 2起動時的旋轉扭矩而穩定地支承該馬達2，而在要求要 以相對於該馬達2的長軸方向直角延伸的安裝用臂部來進 行支承的矛盾的狀況中，選擇使用了上述八字型相互延伸 的安裝用臂部2f、2g來做爲支承構造。 經由呈現上述八字型的一對安裝用臂部2f、2g而以 上述兩個安裝轂部1 b、1 b所進行的上述起動馬達2後部 2b的安裝支承，是藉由從在該起動馬達2的側面來看與 其中心線大致相同高度的位置朝向上述斜後方從該馬達2 延伸的上述一對安裝用臂部2f、2g所進行，藉此，上述 馬達2相對於安裝支承位置是將其重心設定在較低的位置 ’而能進行穩定的支承，能有助於控制上述起動馬達2在 起動時的旋轉扭矩的變化。 -11 - (9) (9)200408764 上述起動馬達2 ’是藉由：以其後部2 b的上述兩個 安裝轂部1 b、1 b所進行且經由呈現上述八字型延伸的一 對安裝用臂部2f、2g的上述安裝支承、以及其前部的前 方突出部2a的上述環狀支承部〗d的上述開孔部]e所進 行的使該開孔部1 e中心線與馬達2的旋轉軸線一致的上 述支承的三點支承’該起動馬達2實質上會被支承爲水平 狀態，並且相對於上述馬達2的安裝支承位置，該馬達2 的重心位置是在略相同高度的位置或是在稍微下方的位置 ’所以㊉以穩疋且堅固的狀態安裝支承該起動馬達2。 第1圖〜第4圖的圖示的實施方式，由於是如上述的 構造’起動馬達2貫質上’是被安裝在上述曲軸箱1上部 的外殼部上所形成的凹部1 a且被收容在其下部，距離該 曲軸箱1的外殼部所描繪的外型線的突出量是被控制得較 小。 於是’ δ亥起動馬達2的安裝位置，會靠近上述曲軸$ ’會讓上述起動馬達2的旋轉軸2d與上述曲軸6的兩軸 之間的距離縮短’所以從該馬達2的旋轉軸2d朝向上述 曲軸6的旋轉驅動力的傳達可以經由一支中間軸4來進行 ’其構造可以簡化’且可減少齒輪等的零件數量，也可抑 制旋轉驅動力在傳達上的耗損。 上述起動馬達2的安裝支承，可以經由從上述馬達2 後部2b朝向斜後方八字型擴張地延伸的一對安裝用臂部 2 f、2 g而以上述安裝轂部1 b、1 b來進行，所以其支承很 堅固，可以得到能適當對應該馬達2的旋轉扭矩的變化的 -12 - (10) (10)200408764 穩定的安裝支承構造。 上述起動馬達2的安裝支承，是藉由：以及該馬達2 則d的上述環狀支承邰1 d所進行的支承、以該馬達2的 後部2b的呈現上述八字型延伸的一對安裝用臂部2f、& 的利用上述安裝轂部lb、lb的實質上是水平狀態的三點 支承，該馬達2的支承，是在從上述起動馬達2的側面來 看與中心高度位置大致相同高度的位置，該馬達2的重心 位置相對於上述安裝支承位置是在略相同高度的位置或是 在稍微下方的位置’所以能得到可適當地對應該馬達2起 動日寸的&E轉扭矩變動的上述起動馬達2的安裝支承構造。 【圖式簡單說明】 第1圖是顯示本發明的主要構造的曲軸箱的縱剖面圖 〇 第2圖是顯示本發明的內燃機的槪觀狀況的從與曲軸 垂直的其中一方向來看的剖面圖。 第3圖是顯示本發明的內燃機的槪觀狀況的從與曲軸 垂直的另一方向來看的剖面圖。 第4圖是本發明的起動馬達安裝部的放大圖。 第5圖是以剖面來顯示以往的內燃機的槪觀狀況與曲 軸箱的一部分構造部的顯示圖。 第6圖是以剖面來顯示以往發明的主要構造部的視圖 - 13- (11) (11)200408764 【圖號說明】 1 :曲軸箱 1 a :凹部 1 b :安裝轂部 1 C :螺栓 1 d :環狀支承部 1 e :開孔部 2 :起動馬達 鲁 2a :起動馬達殼體的前方突出部 2b :起動馬達後部 2c :環狀的彈性體 2 d :旋轉軸 2e :與旋轉軸一體的齒輪部 2f、2g :安裝用臂部 3 :中間齒輪 3 a :大直徑齒輪部 φ 3 b :小直徑齒輪部 4 :中間軸 . 5 :曲軸的被動齒輪 6 _·曲軸 7 :初始從動齒輪 8 ·離合益1 9 :變速機構 1 0 :正時鏈條 -14 > 200408764[Patent Document 1] Japanese Patent Application Laid-Open No. 7-208 1 4 1 (Page 3, Figure! And Figure 2) [Summary of the Invention] [Problems to be Solved by the Invention] The conventional technology described in the above Patent Document 1 The installation of the starter motor is shown in Figures 5 and 6. The starter motor 〇2 is relative to the inner -4-(2) (2) 200408764 gas turbine crankcase 0 1 and relative to the crankcase ο The profile line drawn by the outer shell of the box body 0 from the side view 1 is arranged outside the profile line (see Figure 5). The starter motor 02 and the crankshaft 05 are disposed at positions separated from each other. The distance between the rotary shaft 0 2 d of the starter motor 02 and the two shaft portions of the crankshaft 05 is large, and the starter motor 02 faces the above. The gear transmission of the rotational driving force of the crankshaft 〇5 starts from the gear 〇2 e which is integral with the rotation shaft 0 2 d of the above-mentioned starter motor 02 and passes through the gear 〇3 of the intermediate shaft 〇41 and the intermediate shaft Oh Gear 03 and gear 05! Of crankshaft 05 are transmitted through the intermediate shafts 04! And 042 (refer to FIG. 6). As described above, regarding the mounting structure of the conventional starter motor of the internal combustion engine, the Most of the body structure of the starter motor or the entire body structure is located on the outside of the outline drawn by the crankcase when viewed from the side of the crankcase (the face that intersects the crankshaft perpendicularly). It is assumed that the position of the crankshaft and the starter motor is separated. The distance between the rotation shaft of the starter motor and the crankshaft is large. The transmission of the rotational driving force from the starter motor to the crankshaft is in Gears are used to convey the situation through a plurality of intermediate shafts, and at least two intermediate shafts are used. The gear transmission of the rotational driving force via the plurality of intermediate shafts will not only complicate the power transmission mechanism, but also increase the number of parts such as gears, which will increase the size of the mechanism and transmit the rotational driving force. Efficiency will also increase. (3) (3) 200408764 In the above situation, it is necessary to focus on the improvement of the women's clothing structure of the starter motor of the internal combustion engine, and particularly to simplify the transmission mechanism of the rotational driving force from the starter motor to the crankshaft, and Its improved structure conveys the improvement of efficiency and the reduction of the number of parts to reduce costs. [Means for Solving the Problem and Effects of the Invention] The present invention relates to improvement of a mounting structure of a starter motor of an internal combustion engine for solving the above-mentioned problem. By mounting the starter motor as close as possible to the crankshaft, The installation structure of the starter motor is to shorten the distance between the shaft of the starter motor and the crankshaft and simplify the transmission mechanism of the rotational driving force from the starter motor to the crankshaft. The starter motor has a starter motor, a crankshaft, A driven gear on one side of the crankshaft, an initial transmission gear provided on the other side of the crankshaft, and a gear of a starter motor and a starter motor of an intermediate wheel for transmitting the rotational driving force of the starter motor to the passive gear. The mounting structure is characterized in that: a crankcase includes a housing portion for housing the intermediate gear and the passive gear for transmitting the rotational driving force from the starter motor to the crankshaft, and a housing for receiving the initial gear The receiving portion of the initial driven gear meshed with the transmission gear is sandwiched between the receiving portions corresponding to the two receiving portions. A recessed portion is formed in the outer casing portion of the crankcase upper part of the space area, and the starter motor is housed in the recessed portion. In the state where the starter motor is accommodated, a mounting hub portion for mounting the starter motor is provided corresponding to the starter motor. The housing portion on the upper portion of the crankcase that houses the accommodating portion of the initial driven gear. The first invention is a crankcase, and includes a housing for housing the intermediate gear and the passive gear for transmitting the rotational driving force from the starter motor to the crankshaft in winter (4) (4) 200408764, and A receiving portion that accommodates the initial driven gear that meshes with the initial transmission gear, a recessed portion is formed in a housing portion of the upper portion of the crankcase corresponding to a space region sandwiched by the two receiving portions, and the starter motor is received in the recessed portion, And in the state where the starter motor is stored, the mounting hub portion for mounting the starter motor is provided on a housing portion corresponding to the upper portion of the crankcase that houses the receiving portion that houses the initial driven gear; _ let the starter motor and The arrangement position of the crankshaft is close, which can greatly shorten the distance between the rotary shaft of the starter motor and the crankshaft. When the rotational driving force is transmitted from the rotary shaft of the starter motor to the crankshaft, it is not via a plurality of intermediate shafts as in the past. Method, but the transmission of the rotational driving force is performed through an intermediate shaft, so the Simplification of structure 'reduces the number of parts used to transmit the driving force, and also reduces the wear caused by the rotational driving force when the gear is transmitted. According to a second invention, the starter motor is mounted on the mounting hub portion of the recess and the recessed portion in a stored state, and a pair of positions are provided on an outer shell portion of the crankcase in order to mount the starter motor. It is suitable for accommodating and fixing the vicinity of the front end portion of a pair of mounting arm portions, which are extended so as to expand in a sigmoid shape from the rear end portion of the starter motor or near the end portion. The starter motor is housed in the recessed portion with a low and stable center of gravity and is securely and firmly supported. Since the pair of mounting arm portions are formed in a figure-eight shape, the rotation of the starter motor when the starter motor is started is -7- (5) (5) 200408764 The supporting force of the change in the turning torque is strong, and it can ensure the installation state of the motor in response to the change in the turning torque. [Embodiment] An embodiment of the present invention will be described below with reference to Figs. 1 to 4. FIG. 1 is a longitudinal cross-sectional view showing a direction along a crankshaft (not shown) of a crankcase 1 of an internal combustion engine. In the first figure, a partial structure of the crankcase 1 is shown, and in the drawing, it is described The characteristic structure of the present invention is the starter motor 2 and its surrounding structure. The intermediate gear 3 is shown. The intermediate gear 3 meshes with the gear 2e. The gear 2e is integrated with the rotation shaft 2d of the starter motor 2. The intermediate gear 3 is connected to a crankshaft 6 (not shown). The driven gear 5 on one of the sides is meshed to transmit the rotational driving force of the starter motor 2 to the crankshaft 6 via the intermediate gear 3 (see FIG. 2). The intermediate gear 3 is a gear having a structure having two gear portions of a large-diameter gear portion 3 a and a small-diameter gear portion 3 b. The large-diameter gear portion 3 a of the intermediate gear 3 is made in accordance with the starter motor 2. Rotating shaft 2 (1 is integrally meshed with the gear 2e, and the small-diameter gear portion 3b provided with the intermediate gear 3 meshes with the passive gear 5 provided on one side of the crankshaft 6 (see FIG. 2) The structure is such that the rotational driving force of the starter motor 2 is transmitted to the crankshaft 6 via the meshing of the gear 5. The crankshaft 6 is opposite to one side of the crankshaft 6 that transmits the rotational driving force from the starter motor 2. On the other side, an initial transmission gear (not shown) is provided, and the initial transmission gear meshes with the initial driven gear 7 (6) (6) 200408764. In Figs. 1 to 3, 8 is a clutch, 9 is a transmission mechanism, 10 is a timing chain, and 11 is a cylinder block. The above crankcase 1 ′ is provided with a structural portion for mounting the starter motor 2 on the upper casing, and the structural portion has a recessed portion 1 a Structure, the recess 1 a, In the illustration in FIG. 1, the crankshaft 6 is formed as a receiving part of the intermediate gear 3 and the passive gear 5 that transmits the rotational driving force of the rotation shaft 2 d of the starter motor 2 to the crankshaft 6, that is, the crankshaft. The space area of the crankcase on one side of the gearbox 6 and the gear receiving section of the gear that meshes with the initial transmission gear and the initial driven gear 7 are sandwiched by the space area of the crankcase on the other side of the crankshaft 6. The crankcase interior space corresponds to the upper housing portion of the box body 1. The recessed portion 1a for mounting the starter motor 2 has a cross-sectional shape that is made into a cylindrical shape and a shallow arc shape ( (Refer to FIG. 3), the long axis direction is a structure extending a predetermined length in the above-mentioned cylindrical shape, and the starter motor 2 is arranged in the state shown in FIGS. 1 to 3 in the recess 1a. The above-mentioned arrangement operation of the motor 2 is performed by accommodating the lower part of the arrangement state of the starter motor 2 in the recessed portion 1 a, thereby allowing the starter motor 2 to arrange the state of the recessed portion 1 a. , The above-mentioned starter motor 2 The amount of protrusion from the contour line drawn from the casing portion of the crankcase 1 is suppressed to a considerable degree. The arrangement state of the starter motor 2 to the recessed portion 1 a, the starter motor 2 and the front rotary shaft 2 d The side is supported by a -9- (7) (7) 20040764 annular support portion 1 d formed with an opening portion 1 e. The opening portion 1 e is provided so as to protrude from the upper casing portion of the crankcase 1 described above. The second part 2 b is fixed to a mounting hub portion lb protruding a predetermined amount from the housing portion of the crankcase 1 via a pair of mounting arm portions 2 f and 2 g extending obliquely rearward from the rear portion 2 b of the starter motor 2. 1b ° The front portion of the starter motor 2 is supported by the ring-shaped support portion 1 d. More specifically, the front portion 2a of the housing portion of the starter motor 2 is passed through the ring-shaped portion. An elastic member 2 c (for example, an O-ring) is fitted into a recessed portion 1 a supported on the upper casing portion of the crankcase 1, and a ring-shaped opening portion 1 e provided on one of the ends thereof in the long axis direction, This way. The fitting support of the front projection 2a of the motor case by the opening portion 1e is substantially the center of the opening portion 1e coincides with the center of the rotation shaft 2d of the starter motor 2 and from The relationship can be deduced that the center of the above-mentioned opening portion 1 e is a relationship that substantially coincides with the center in the longitudinal direction of the motor 2. The starter motor 2 rear portion 2b is supported by the motor 2 via the pair of mounting arm portions 2f, 2g, and more specifically, via the recess 1a in the upper casing of the crankcase 1 in the long axis direction. The installation of the two protruding hub portions 1 b and 1 b at the other end forming the end is performed (see FIG. 4). The respective front ends of the pair of mounting arm portions 2f, 2g extending obliquely rearward from the rear portion 2b of the starter motor 2 are fixed to the two mounting hub portions lb, lb using bolts, etc., respectively. The upper part of the -10-(8) (8) 200408764 two mounting hubs 1 b, 1 b, as can be seen from the first figure, are provided in the initial transmission gear which corresponds slightly to the above-mentioned crankcase 2 The upper part of 7 is the position on the outer casing part of the upper part of the crankcase 1. The pair of mounting arm portions 2f, 2g extending from the rear portion 2b of the starter motor 2 extends slightly obliquely from the rear portion 2b of the starter motor 2 toward the oblique rear as shown in the enlarged view in FIG. As shown in FIGS. 3 and 4, the figure 8 extending diagonally from the rear part 2 b of the motor 2 to the sigmoid of the mounting arm parts 2 f and 2 g is due to the mounting arm part 2 on the right side. The f-side has a hot cylinder 1 1 'but a' compromising 'design. In other words, because of the existence of the cylinder block 11, the right-hand mounting arm portion 2f cannot extend at right angles with respect to the long-axis direction of the motor 2. On the other hand, in order to resist the start-up motor 2 from starting, The motor 2 is supported stably by the rotating torque of the motor. However, in a situation where it is required to support the mounting arm portion extending at right angles to the long axis direction of the motor 2, the above-mentioned splayed mutual extension is selected. The mounting arm portions 2f and 2g are used as support structures. The mounting and support of the rear portion 2b of the starter motor 2 through the pair of mounting arm portions 2f and 2g exhibiting the aforementioned figure-shaped mounting arms by the two mounting hub portions 1b and 1b are performed by the starter motor 2 When viewed from the side, the position of approximately the same height as the center line is performed toward the pair of mounting arm portions 2f, 2g extending obliquely rearward from the motor 2, whereby the center of gravity of the motor 2 relative to the mounting support position is Setting it at a lower position allows stable support, and helps control the change in the rotation torque of the starter motor 2 at the time of starting. -11-(9) (9) 200408764 The starter motor 2 'is a pair of mountings performed by the two mounting hubs 1b, 1b at the rear portion 2b and extending through the figure eight The mounting support of the arm portions 2f, 2g, and the annular support portion of the front protruding portion 2a of the front portion of the opening portion] e are performed to center the opening portion 1e with the motor 2 Three-point support of the above-mentioned support with the same rotation axis' The starter motor 2 is substantially supported in a horizontal state, and the position of the center of gravity of the motor 2 is at a position of approximately the same height or The starter motor 2 is installed and supported in a slightly lower position. The embodiment shown in FIGS. 1 to 4 has a structure as described above, and the 'starter motor 2' is a recessed portion 1 a formed on the housing portion of the upper portion of the crank case 1 and is accommodated in the structure. In the lower part, the amount of protrusion of the contour line drawn from the casing portion of the crankcase 1 is controlled to be small. Then, the installation position of the delta starter motor 2 will be close to the crankshaft. 'The distance between the rotary shaft 2d of the starter motor 2 and the two shafts of the crankshaft 6 will be shortened.' The transmission of the rotational driving force of the crankshaft 6 can be carried out through a single intermediate shaft 4 'the structure can be simplified', the number of parts such as gears can be reduced, and the transmission loss of the rotational driving force can be suppressed. The mounting and supporting of the starter motor 2 may be performed by the mounting hubs 1 b and 1 b through a pair of mounting arm portions 2 f and 2 g that extend from the rear portion 2 b of the motor 2 to an oblique rear sigma shape. Therefore, its support is very strong, and a stable mounting support structure can be obtained which can appropriately respond to the change of the rotation torque of the motor 2 (-12) (10) (10) 200408764. The mounting support of the starter motor 2 is supported by the ring-shaped support 邰 1 d of the motor 2 and d, and a pair of mounting arms extending in a figure-eight shape in the rear portion 2 b of the motor 2. The three-point support of the portion 2f, & using the mounting hub portions lb, lb in a substantially horizontal state, and the support of the motor 2 is approximately the same height as the center height position when viewed from the side of the starter motor 2 Position, the position of the center of gravity of the motor 2 is at a position that is slightly the same height or slightly lower than the above-mentioned mounting support position, so it is possible to obtain a & E turning torque that can appropriately respond to the starting inch of the motor 2 The mounting support structure of the starter motor 2 described above. [Brief Description of the Drawings] FIG. 1 is a longitudinal sectional view of a crankcase showing a main structure of the present invention. FIG. 2 is a cross-sectional view of the internal combustion engine of the present invention, viewed from one direction perpendicular to the crankshaft. Illustration. Fig. 3 is a cross-sectional view of the internal combustion engine of the present invention, viewed from another direction perpendicular to the crankshaft. Fig. 4 is an enlarged view of a starter motor mounting portion of the present invention. Fig. 5 is a cross-sectional view showing an overview of a conventional internal combustion engine and a part of a crankcase structure. Fig. 6 is a cross-sectional view showing the main structural parts of the conventional invention.-13- (11) (11) 200408764 [Description of Drawing Numbers] 1: Crankcase 1a: Recess 1b: Mounting Hub 1C: Bolt 1 d: annular support portion 1 e: opening portion 2: starter motor 2a: front protrusion of starter motor case 2b: starter motor rear portion 2c: annular elastic body 2 d: rotary shaft 2e: integrated with the rotary shaft Gear parts 2f, 2g: Mounting arm part 3: Intermediate gear 3 a: Large-diameter gear part φ 3 b: Small-diameter gear part 4: Intermediate shaft 5: Crankshaft passive gear 6 _ · Crankshaft 7: Initial driven Gear 8Clutch benefit 19: Gear shift mechanism 1 0: Timing chain-14 > 200408764