M418968 五、新型說明： 【新型所屬之技術領域】 本創作係關於一種減壓裝置，尤指一種適用於車輛、 方便拆裝之引擎減壓裝置。 【先前技術】 習知内燃機引擎中，為解決當曲柄軸於内燃機媳火而 • 停止後若恰停於壓缩行程，則下次啟動時需克服較大啟動 阻抗之問題，發展出所謂的引擎減壓裝置，例如離心式減 壓裝置，此類裝置在中華民國專利號1330216中有所揭露。 請參考圖1，所示為一習知減壓裝置组裝於汽缸頭13 内之剖面圖，圖中示出減壓裝置之離心塊3樞設於鍊輪6之 一側’減壓裝置之減壓心軸4穿設於凸輪軸7之内部。 參考圖2 ’其為習知減壓裝置之分解圖。習知減壓裝 置中固疋凸緣14壓配於凸輪轴7上並與鍊輪6相互鎖附。 鲁 另有一離心塊3透過一樞柱1樞設於鍊輪6上，離心塊3依據 凸輪軸7轉速而受不同離心力作用。減壓裝置之設計為，當 離心塊3所受離心力高於扭簧2之預拉力，則位於閥動凸輪8 外環面所凹設之徑向滑槽丨丨中的頂桿9會呈完全收納於徑 向’骨槽1 1中之狀態，亦即低於閥動凸輪8之外環面，此時無 減璧作用。通常於鍊輪6上會有一限位柱5限制住離心塊3 的轉動範圍。 而當離心塊3所受離心力漸漸降低，在低於扭簧2之預 拉力時’離心塊3會開始相對於鍊輪6梅轉，也促使離心塊3 3 M418968 上之一撥動凸塊丨〇帶動減壓心軸4轉動。而當減壓心軸4轉 動，減塵心軸4上偏心設置之頂推凸塊12會開始頂推頂桿 9’促使頂桿9從收納狀態轉變成突出閥動凸輪8外環面之狀 態，此時有減壓作用。 上述習知引擎減壓裝置存在有一缺點，即進行裝配或 拆卸時，容易發生未持穩減壓心軸而使其軸向滑移。一旦 減壓心軸滑移，頂桿也將因此脫離徑向滑槽並掉入引擎腔 肚内。P，例如汽缸頭、甚至曲軸箱，如此將需花費更多時 間與人力去找出掉落之頂桿，延誤組裝或拆卸步驟。 【新型内容】 本創作之主要目的係在提供一種引擎減壓裝置，俾能 解決組裝期間減壓心軸容易滑出凸輪軸而使頂桿掉落引擎 内部腔室之問題。 為達成上述目的，本創作之引擎減壓裝置係組設於一 凸輪軸總成與—鍊輪上，凸輪軸總成包括一凸輪軸、一閥 動凸輪，其中凸輪軸包括有一軸向腔室閥動凸輪套固於 凸輪軸上且包括有一徑向滑槽，徑向滑槽連通軸向腔室並 開口於閥動凸輪之外環面，鍊輪固定於凸輪轴而同步轉動。 引擎減壓裝置包括一離心塊 '一減壓心軸、一頂桿' —預力構件及一止擋銷。上述離心塊是樞設於鍊輪上，包 括有一撥動凸塊。 上述減壓心轴是穿設於軸向腔室，其一端面凹設有一 撥動彳曰另一端面突設有一頂推凸塊。離心塊之撥動凸塊 M418968 位於減壓心軸之撥動槽中。 上述頂桿滑移於閥動ώ輪之徑向滑槽中，且頂桿之環 面上凹叹有-頂推槽。減壓心軸之頂推ώ塊依據減壓心軸 之轉動而於頂推槽中頂推前述頂桿，以使頂桿選擇式突出 或收納於徑向滑槽。 上述預力構件一端抵頂於離心塊，另一端則抵頂於鍊 輪’以施予離心塊一預力。 凸輪軸之外表面設有一銷孔係連通至軸向腔室，止擔 銷係穿過銷礼進入軸向腔室。減壓心軸之外表面還設有一 心軸凸緣，止擋銷軸向上位於心軸凸緣與鍊輪之間，用以 軸向限位減壓心軸，使頂推凸塊保持於頂推槽中。 藉由上述結構設計，減壓裝置在組裝或拆卸時，因為 減壓心軸會以其心軸凸緣卡抵於止擋銷，故不會滑出軸向 腔室而導致頂桿也滑出徑向滑槽。 本創作中’銷孔的位置並不特別限定，例如可以設置 在凸輪軸之一軸頸部。此場合中止擋銷可以用滑配方式置 入銷孔，並由一軸承進行徑向限位，避免止擋銷滑出銷孔， 而且之後也可以輕易取出止擋銷。另外，即使不是在轴頸 4 ’銷孔叮没置在凸輪轴上有其它構件環繞之區段，例如 一固定凸緣（用於鎖附前述鍊輪）所套設之位置。 或者’鎖礼也可以設置在凸輪軸上未被遮覆之自由區 段。在此場合中，可考慮用緊配方式將止擋銷置入銷孔以 避免止擋銷滑出。 5 M418968 【貫施方式】 參考圖3〜5，分別為第一較佳實施例之減壓裝置分解 圖、組裝圖、具減璧裝置之引擎汽缸頭剖視圖。圖中顯示 汽缸頭40内組設有一晶輪軸總成21、一鍊輪22、及減壓裝 置。詳細而言，凸輪軸總成21包括一凸輪軸23、一閥動凸 輪24,凸輪轴23包括有一軸向腔室23卜閥動凸輪24套固於 凸輪軸23上，且其内部開設有一連通至軸向腔室231之徑向 滑槽241 ’徑向滑槽241並開口於閥動凸輪24之外環面242。 凸輪軸23透過套設在其轴頸部230之一滾珠轴承37而 安裝定位在汽缸頭40内之一凸輪軸座41。凸輪軸23之轴頸 部230表面凹設一銷孔23 2係連通至軸向腔室231。 一固定凸緣25壓配於凸輪轴23上，並開設有二凸緣鎖 附孔251，而鍊輪22亦開設有對應於凸緣鎖附孔251之二輪 鎖附孔221與222,其中輪鎖附孔222呈一弧形長槽狀。習知 上，鍊輪22即是透過鎖附方式而與凸輪軸總成21互相連接 固定。利用二鎖附件34穿過二輪鎖附孔22 1,222及二凸緣鎖 附孔25 1使固定凸緣25與鍊輪22相對固定，鎖附件34使用螺 栓，其它等效鎖附件如螺絲亦適用。 引擎減壓裝置包括一離心塊26 '減壓心軸27、一頂桿 28、一預力構件29以及一限位柱35。透過一樞柱33依序穿 過離心塊26、鍊輪22上之樞孔225，將離心塊26鉚接樞設在 練輪22上。沿軸向’離心塊26位置是在以鍊輪22為界相對 於閥動凸輪24之另一側。限位柱35穿過鍊輪22之限位孔223 而鉚固於鍊輪22上’其作用為限制離心塊26相對於鍊輪22 M418968 的轉動範圍。 本例中，預力構件29使用一扭簧，其套於樞柱33而以 框柱33為樞轉軸’且一端抵頂於離心塊26，另一端抵頂於 鍊輪22上所開設之扣孔224，藉此施予離心塊26—預力。 減壓心軸27伸入凸輪軸23之轴向腔室231。減壓心軸 27於一端面凹設有一徑向延伸之撥動槽272,於另一端面軸 向突設有一頂推凸塊271。離心塊26之撥動凸塊261是對應 伸入減壓心軸27之撥動槽272中。 頂桿28位於閥動凸輪24之徑向滑槽241中k可滑移。 並且’頂桿28之環面281上凹設有一頂推槽282供減壓心軸 27之頂推凸塊271伸入頂推。頂推槽282受頂推之面可設計 為平面或非平面，並不特別限制。 此外，減壓心軸27之外環面還設有一心軸凸緣273。 一止擋銷36穿過凸輪轴23之銷孔232並伸入轴向腔室231。 當心軸凸緣273與止擋銷36接觸時，減壓心軸27之頂推凸塊 271仍位於頂推槽282申，如此才能發揮防止頂桿28跑出徑 向滑槽241之功效。本實施例中，銷孔232(及止擋銷36)特 別配置成軸向重疊於軸承37(及轴頸部230)。 減壓心軸27之頂推凸塊271是依據減壓心軸27之轉動 而於頂桿28之頂推槽282中頂推頂桿28,藉此使頂桿28選擇 式突出或收納於徑向滑槽241。 當引擎停止運轉時，離心塊26失去可抵抗預力構件29 預力之離心力作用而位於一特定位置》而頂桿28因為受減 壓心軸27之頂推凸塊27 1之頂推，突出於閥動凸輪24之徑向 7 M418968 滑槽24丨使一搖臂42產生擺動位移，以達到引擎減壓之功 效。 當引擎發動至使離心塊26伴隨鍊輪22轉動所受到之 離心力作用大於預力構件29預力時，離心塊26會被甩開， 亦即以框柱33為轉軸相對於鍊輪22開始轉動，促使其上之 撥動凸塊261於減壓心軸27之撥動槽272中撥轉減壓心轴 27，連帶地也使減壓心軸27之頂推凸塊271於頂推槽282中 頂推頂桿28之狀況有所改變。亦即，減壓心軸27之轉動造 成頂推凸塊271也產生轉動偏位，也因偏位之發生而使頂桿 28由突出位置滑移縮入至收納位置。 由上述可知，本創作因為增設一心軸凸緣273與一止 擋銷36之組合，當心軸凸緣273抵頂到止擋銷36時被軸向限 位’減壓心軸27不會滑出凸輪軸23之軸向腔室231，頂桿28 也因此不會掉出徑向滑槽24卜避免浪費人力與時間去尋找 掉落零件❶此外’本例所述止擋銷36位於軸承37厚度範圍 内之設計有一優點，亦即可將止擋銷36滑配於銷孔232，由 轴承3 7阻擋止擋銷36徑向滑出，如此一來，止擋銷36在以 後是可以容易取出的。 參考圖6，為第二實施例之具減壓裝置之引擎汽缸頭 剖視圖。本實施例減壓裝置之構成大致與第一例相同，其 差異處在於凸輪軸51之銷孔511 (及止擋銷54)位置不是轴 向重#於軸頸部56 ’而是軸向重疊於與鍊輪55相互鎖附固 定之固定凸緣53，止擋銷54由固定凸緣53阻擋住避免滑 出。如此設計除了減壓心軸52因心軸凸緣521受止擋銷54 M418968 卡擎而不會掉出凸輪轴51之基本功效外，也同樣具有第— 例之優點，即容易在以後取出止擋銷54。 參考圖7 ’為第三實施例之具減壓裝置之引擎汽缸頭 剖視圖。本實施例減難置與第—例之差異在於，凸輪轴 61之銷孔611(及止擋銷63)位置不是軸向重疊於軸頸部“ο 或固定凸緣64，而是曝露於空間、沒有拘束之自由區段 6 1 2在此例申，便可考慮將止擋銷63緊配於銷孔61 1，以 避免任意滑出。當然，此設計同樣有減壓心軸62與頂桿因 心軸凸緣621受止擋銷63卡掣而不會掉出凸輪軸61之基本 功效。 上述實施例僅係為了方便說明而舉例而已，本創作所 主張之權利範圍自應以申請專利範圍所述為準，而非僅限 於上述貫施例。 【圖式簡單說明】 圖1係習知引擎汽缸頭剖視圖。 圖2係習知減壓裝置之分解圖。 圖3係本創作第一較佳實施例之減壓裝置分解圖。 圖4係本創作第一較佳實施例之減壓裝置組裝圖。 圖5係本創作第一較佳實施例之引擎汽缸頭剖視圖。 圖6係本創作第二較佳實施例之引擎汽缸頭剖視圖。 圖7係本創作第三較佳實施例之引擎汽缸頭剖視圖。 【主要元件符號說明】 9 M418968 極柱1 離心塊3 限位柱5 Λ輪軸7 頂桿9 徑向滑槽11 汽缸頭13 凸輪軸總成2 1 輪鎖附孔221,222 扣孔224 凸輪軸23,51，61 軸向腔室23 1 閥動凸輪24 外環面242 凸緣鎖附孔251 撥動凸塊261 頂推凸塊27 1 心軸凸緣273,521,62 1 環面281 預力構件29 鎖附件34 止擋銷36,54,63 汽缸頭40 搖臂42 扭簧2 減壓心軸4 鍊輪6 閥動凸輪8 撥動凸塊10 頂推凸塊12 固定凸緣14 鍊輪22,55 限位孔223 樞孔225 軸頸部 230,56,610 銷孔 232,51 1,61 1 徑向滑槽241 固定凸緣25,53,64 離心塊2 6 減壓心軸27,52,62 撥動槽272 頂桿28 頂推槽282 極柱3 3 限位柱3 5 轴承3 7 凸輪軸座41 自由區段612 10M418968 V. New description: [New technical field] This creation is about a decompression device, especially an engine decompression device suitable for vehicles and easy to disassemble. [Prior Art] In the conventional internal combustion engine, in order to solve the problem that when the crankshaft is stopped in the compression stroke after stopping the internal combustion engine, it is necessary to overcome the problem of large starting impedance at the next startup, and the so-called engine reduction is developed. Pressing devices, such as centrifugal pressure reducing devices, are disclosed in the Republic of China Patent No. 1330216. Referring to FIG. 1, a cross-sectional view of a conventional pressure reducing device assembled in a cylinder head 13 is shown. The centrifugal block 3 of the pressure reducing device is pivotally disposed on one side of the sprocket 6 The pressure reducing mandrel 4 is bored inside the cam shaft 7. Referring to Figure 2', it is an exploded view of a conventional pressure reducing device. In the conventional pressure reducing device, the fixing flange 14 is press-fitted to the cam shaft 7 and interlocked with the sprocket 6. Another centrifugal block 3 is pivotally mounted on the sprocket 6 through a pivot post 1, and the centrifugal block 3 is subjected to different centrifugal forces depending on the rotational speed of the camshaft 7. The pressure reducing device is designed such that when the centrifugal force of the centrifugal block 3 is higher than the pre-tensioning force of the torsion spring 2, the ejector pin 9 located in the radial sliding groove 凹 recessed in the outer annular surface of the valve moving cam 8 is completely completed. The state accommodated in the radial 'bone groove 1 1 ', that is, lower than the outer ring surface of the valve cam 8 , at this time, there is no mitigating effect. Usually, a limit post 5 is provided on the sprocket 6 to limit the range of rotation of the centrifugal block 3. When the centrifugal force of the centrifugal block 3 is gradually reduced, the centrifugal mass 3 will start to rotate relative to the sprocket 6 at a lower pre-tension than the torsion spring 2, and also causes one of the centrifugal blocks 3 3 M418968 to move the bump 丨The 减压 drives the decompression mandrel 4 to rotate. When the decompression mandrel 4 rotates, the eccentric protrusion 12 on the eccentric shaft 4 of the dust reduction mandrel 4 starts to push the ejector pin 9' to cause the ejector pin 9 to change from the accommodating state to the state of protruding the outer ring surface of the valve cam 8 At this time, there is a decompression effect. The above-described conventional engine decompression device has a drawback in that, when assembling or disassembling, the unsteady decompression mandrel is liable to cause axial sliding. Once the decompression mandrel slips, the ram will also detach from the radial chute and fall into the engine cavity. P, such as the cylinder head, or even the crankcase, will take more time and manpower to find the falling ram and delay the assembly or disassembly steps. [New Content] The main purpose of this creation is to provide an engine decompression device that solves the problem that the decompression mandrel easily slides out of the camshaft during assembly and causes the jack to drop into the engine's internal chamber. In order to achieve the above object, the engine decompression device of the present invention is assembled on a camshaft assembly and a sprocket. The camshaft assembly includes a camshaft and a valve cam, wherein the camshaft includes an axial chamber. The valve cam is sleeved on the cam shaft and includes a radial sliding slot. The radial sliding slot communicates with the axial cavity and opens outside the valve cam. The sprocket is fixed to the camshaft for synchronous rotation. The engine decompression device includes a centrifugal block 'a decompression mandrel, a jack' - a pre-force member and a stop pin. The centrifugal block is pivotally mounted on the sprocket and includes a toggle projection. The decompression mandrel is disposed in the axial chamber, and one end surface is concavely provided with a dialing jaw and the other end surface is provided with an pushing protrusion. The toggle block of the centrifugal block M418968 is located in the shifting groove of the decompression mandrel. The ejector rod slides in the radial sliding groove of the valve moving wheel, and the apex of the ejector pin is sagged with the ejector groove. The top pushing block of the decompression mandrel pushes the top rod in the pushing groove according to the rotation of the decompression mandrel, so that the jack is selectively protruded or received in the radial chute. One end of the pre-stress member abuts against the centrifugal block, and the other end abuts against the sprocket to apply a pre-stress to the centrifugal block. The outer surface of the camshaft is provided with a pin hole that communicates with the axial chamber, and the pin is passed through the pin to enter the axial chamber. The outer surface of the decompression mandrel is further provided with a mandrel flange, and the stop pin is axially located between the mandrel flange and the sprocket for axially limiting the decompression mandrel so that the thrusting projection is held at the top Push in the slot. With the above structural design, when the pressure reducing device is assembled or disassembled, since the pressure reducing mandrel is stuck against the stop pin with its mandrel flange, it does not slip out of the axial chamber and the ejector rod also slides out. Radial chute. The position of the pin hole in the present creation is not particularly limited, and for example, it may be provided on one of the camshaft shafts. In this case, the stop pin can be placed into the pin hole by sliding fit, and the bearing is radially limited to prevent the stop pin from slipping out of the pin hole, and the stop pin can be easily removed later. Further, even if the journal 4' pin hole is not placed on the cam shaft, there is a section surrounded by other members, such as a fixing flange (for locking the aforementioned sprocket). Alternatively, the lock can also be placed on a free section of the camshaft that is not covered. In this case, it is conceivable to place the stop pin into the pin hole in a tight fit to prevent the stop pin from slipping out. 5 M418968 [Practical Mode] Referring to Figs. 3 to 5, respectively, the exploded view of the pressure reducing device of the first preferred embodiment, the assembled view, and the cross-sectional view of the engine cylinder head with the reducing device. The figure shows a cylinder shaft assembly 21, a sprocket 22, and a pressure reducing device in the cylinder head 40. In detail, the camshaft assembly 21 includes a camshaft 23 and a valve cam 24, and the camshaft 23 includes an axial chamber 23, and the valve cam 24 is sleeved on the camshaft 23, and has a connection therein. It passes to the radial chute 241 'the radial chute 241 of the axial chamber 231 and opens to the outer annular surface 242 of the valve cam 24 . The camshaft 23 mounts a camshaft seat 41 positioned in the cylinder head 40 through a ball bearing 37 that is sleeved on one of its journals 230. A pin hole 23 2 is recessed in the surface of the journal portion 230 of the cam shaft 23 to communicate with the axial chamber 231. A fixing flange 25 is press-fitted on the camshaft 23 and has two flange locking holes 251, and the sprocket 22 is also provided with two wheel locking holes 221 and 222 corresponding to the flange locking holes 251, wherein the wheel The locking hole 222 has an arcuate long groove shape. Conventionally, the sprocket 22 is fixedly coupled to the camshaft assembly 21 by means of a locking means. The two flange attachments 34 are passed through the two-wheel locking holes 22, 222 and the two flange locking holes 25 1 to fix the fixing flange 25 to the sprocket 22, the locking attachment 34 uses a bolt, and other equivalent locking accessories such as screws are also suitable. The engine decompression device includes a centrifugal block 26' decompression mandrel 27, a jack 28, a pre-force member 29, and a limit post 35. The pivoting block 26 and the pivot hole 225 of the sprocket 22 are sequentially passed through a pivot post 33, and the centrifugal block 26 is riveted and pivoted on the training wheel 22. The position of the centrifugal block 26 in the axial direction is on the other side of the valve cam 22 with the sprocket 22 as the boundary. The limit post 35 is threaded through the stop hole 223 of the sprocket 22 and is riveted to the sprocket 22, which acts to limit the range of rotation of the centrifugal block 26 relative to the sprocket 22 M418968. In this example, the pre-stress member 29 uses a torsion spring which is sleeved on the pivot post 33 with the frame post 33 as the pivot axis 'and one end abuts against the centrifugal block 26 and the other end abuts against the buckle provided on the sprocket 22 Hole 224, thereby applying centrifugation block 26 - pre-force. The pressure reducing mandrel 27 projects into the axial chamber 231 of the camshaft 23. The decompression mandrel 27 is concavely provided with a radially extending dial groove 272 at one end surface, and an thrust projection 271 is axially protruded from the other end surface. The toggle projection 261 of the centrifugal block 26 is correspondingly inserted into the dial groove 272 of the pressure reducing spindle 27. The jack 28 is located in the radial slot 241 of the valve cam 24 and is slidable. And a pushing groove 282 is recessed on the toroidal surface 281 of the ejector pin 28 for the pushing protrusion 271 of the decompression mandrel 27 to extend into the pushing. The surface of the thrust groove 282 that is pushed up may be designed to be flat or non-planar, and is not particularly limited. In addition, a toroidal flange 273 is provided on the outer annular surface of the pressure reducing mandrel 27. A stop pin 36 passes through the pin bore 232 of the camshaft 23 and projects into the axial chamber 231. When the mandrel flange 273 is in contact with the stop pin 36, the push-pull projection 271 of the decompression mandrel 27 is still located in the thrust groove 282, so as to prevent the plunger 28 from running out of the radial chute 241. In the present embodiment, the pin holes 232 (and the stop pins 36) are specifically arranged to overlap the bearing 37 (and the journal portion 230) in the axial direction. The pushing protrusion 271 of the decompression mandrel 27 pushes the jack 28 in the pushing groove 282 of the jack 28 according to the rotation of the pressure reducing mandrel 27, thereby causing the jack 28 to be selectively protruded or accommodated in the diameter To the chute 241. When the engine is stopped, the centrifugal block 26 loses its centrifugal force against the pre-stressing member 29 and is in a specific position, and the jack 28 is pushed by the pushing protrusion 27 1 of the decompression mandrel 27 to protrude. In the radial direction of the valve cam 24, the 7 M418968 chute 24 丨 causes a rocker arm 42 to generate a swinging displacement to achieve the effect of decompressing the engine. When the engine is started to cause the centrifugal force of the centrifugal block 26 to be rotated by the sprocket 22 to be greater than the pre-force member 29 pre-force, the centrifugal block 26 is split, that is, the frame 33 is rotated relative to the sprocket 22. The dialing protrusion 261 is urged to rotate the decompression mandrel 27 in the dialing groove 272 of the decompression mandrel 27, and the pushing depressor 27 of the decompression mandrel 27 is also pushed into the pushing groove 282. The condition of the mid-top ejector lever 28 has changed. That is, the rotation of the decompression mandrel 27 causes the urging projection 271 to also generate a rotational offset, and the ejector 28 is also slidably retracted from the projecting position to the stowed position due to the occurrence of the eccentricity. As can be seen from the above, the present invention is axially restrained when the mandrel flange 273 abuts against the stop pin 36 because of the addition of a combination of a mandrel flange 273 and a stop pin 36. The decompression mandrel 27 does not slip out. The axial chamber 231 of the camshaft 23, so that the ram 28 does not fall out of the radial chute 24, avoids wasting manpower and time to find the drop part. Further, the stop pin 36 is located at the thickness of the bearing 37. The design in the range has the advantage that the stop pin 36 can be slidably fitted to the pin hole 232, and the stop pin 36 can be prevented from sliding radially out by the bearing 37, so that the stop pin 36 can be easily taken out later. of. Referring to Figure 6, there is shown a cross-sectional view of an engine cylinder head with a pressure reducing device of the second embodiment. The configuration of the decompression device of this embodiment is substantially the same as that of the first example, and the difference is that the pin holes 511 (and the stop pins 54) of the cam shaft 51 are not axially overlapped with the axial portion 56' but axially overlapped. The fixing flange 53 is interlocked with the sprocket 55, and the stopper pin 54 is blocked by the fixing flange 53 to prevent slipping out. In this way, in addition to the basic function of the decompression mandrel 52 because the mandrel flange 521 is prevented from falling out of the camshaft 51 by the stop pin 54 M418968, it also has the advantage of the first example, that is, it is easy to take out later. Stop pin 54. Referring to Figure 7', there is shown a cross-sectional view of an engine cylinder head with a pressure reducing device of the third embodiment. The difference between the dampening and the first embodiment of the present embodiment is that the pin holes 611 (and the stop pins 63) of the cam shaft 61 are not axially overlapped with the shaft neck "o" or the fixing flange 64, but are exposed to the space. The unconstrained free section 6 1 2 can be considered to fit the stop pin 63 to the pin hole 61 1 to avoid any slipping out. Of course, this design also has a decompression mandrel 62 and a top. The basic effect of the rod due to the clamping of the mandrel flange 621 by the stop pin 63 without falling out of the cam shaft 61. The above embodiments are merely exemplified for convenience of explanation, and the scope of claims claimed by the present invention is patented. The description of the scope is not limited to the above-mentioned embodiments. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view of a conventional engine cylinder head. Fig. 2 is an exploded view of a conventional pressure reducing device. Figure 4 is an assembled view of the pressure reducing device of the first preferred embodiment of the present invention. Figure 5 is a cross-sectional view of the engine cylinder head of the first preferred embodiment of the present invention. A cross-sectional view of the engine cylinder head of the second preferred embodiment is created. Cross-sectional view of the engine cylinder head of the embodiment. [Main component symbol description] 9 M418968 pole 1 centrifugal block 3 limit column 5 Λ axle 7 ejector 9 radial chute 11 cylinder head 13 camshaft assembly 2 1 wheel lock attachment hole 221,222 Buckle 224 Camshaft 23,51,61 Axial chamber 23 1 Valve cam 24 Outer ring face 242 Flange lock hole 251 Pushing lug 261 Pushing lug 27 1 Mandrel flange 273,521,62 1 Torus 281 Pre-force member 29 Locking attachment 34 Stop pin 36, 54, 63 Cylinder head 40 Rocker arm 42 Torsion spring 2 Pressure reducing mandrel 4 Sprocket 6 Valve cam 8 Shifting lug 10 Pushing lug 12 Fixed Flange 14 Sprocket 22, 55 Restriction hole 223 Pivot hole 225 Shaft neck 230, 56, 610 Pin hole 232, 51 1, 61 1 Radial chute 241 Fixing flange 25, 53, 64 Centrifugal block 2 6 Decompression core Shaft 27, 52, 62 Shifting groove 272 Plunger 28 Pushing groove 282 Pole pole 3 3 Retaining post 3 5 Bearing 3 7 Camshaft seat 41 Free section 612 10