200907162 九、發明說明： 【發明所屬之技術領域】 本發明係關於-種減壓裝置，尤指一種適 並具有使吹漏氣之油氣分離效果之引擎減壓裝置。、皁輛， 【先前技術】 在習知引擎汽缸頭内配置有閱動裝置，_ 輪軸總成包括凸輪轴及其上之至少一凸輪，鍊 凸輪軸上。閥動裝置是透過鍊條獲得曲柄的轉動网力、旦^ 驅動。鍊輪上會固定一離心盤，藉由離心力作用使Lt 吹漏氣產生油氣分離效果。 之· 15 Ο 另外，習知内燃機引擎中，為解決當曲柄轴 媳火而停止後若恰停於壓縮行程，則下次啟動時服機 大啟動阻抗之問題，發展出所謂的引擎減壓裝置 = 心式減壓裝置。圖1所示為—習知減壓裝置組裝於汽缸頭Γ3 内之剖面圖，圖中示出_置之離心塊3樞設於鍊輪仏 -側’減Μ裝置之減塵心軸4穿設於凸輪軸7之内部。 參考圖2與圖3,其分別為習知減壓裝置之 裝圖。習知減厂堅裝置中，固定凸緣_於凸輪轴7上並愈 鍊輪6相互鎖附。另有—離心塊_^__ 上，離心塊3依據凸輪軸7轉速而受不同離心力作用。㈣ 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η中的頂桿 9會呈完全收納於徑向滑槽llt之狀態，亦即低於閥動凸= 20 200907162 8之外環面’此時無減壓作用。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，在低於預力彈等2 之預拉力時，離心塊3會開始相對於鍊輪6枢轉，也促使離 5 心塊3上之一撥動凸塊1 〇帶動減壓心軸4轉動。而當減壓心 轴4轉動’減壓心轴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。 I 上述習知減壓裝置因鍊輪6—側之空間已設有離心塊 10 3，右再加裝一離心盤於鍊輪6，會導致組裝程序上的困難 度，因空間狹小致使吊掛鍊條於鍊輪6時容易受離心盤阻 擔。由上述可知，習知設計無法兼顧有引擎減壓功能以及 使吹漏氣油氣分離之功能，導致機油消耗量變大。 15 【發明内容】 •本表月之引擎減壓裝置係組設於一凸輪軸總成與一鍊 輪上，其中凸輪軸總成包括一凸輪轴、一閥動凸輪、及— 固定凸緣。 凸輪軸包括有一轴向腔室，閥動凸輪套固於凸輪軸上 20且包括有一捏向滑槽，徑向滑槽連通上述轴向腔室並開口 2閥動凸輪之外環面。固定凸賴配於凸輪軸上且包括有 凸緣鎖附孔，鍊輪包括有對應於上述凸緣鎖附孔之輪鎖 附孔。 上述引擎減壓裝置包括有一離心塊、一減壓心軸、一 200907162 、及頂彳干。離心塊樞設於鍊輪上，包括有一撥 動凸塊/咸壓心轴穿設於鍊輪與軸向腔室，其一端面凹設 有撥動槽，另—端面突設有一頂推凸塊，離心塊之撥動 凸塊位於撥動槽中。 5 …上述預力構件—端抵頂於離心塊另—端抵頂於鍊輪， 以施予離心塊一預力。頂桿滑移於閥動凸輪之徑向滑槽 ^ ’頂桿之環面上凹設有-頂推槽，其中頂推凸塊依據減 堡心軸之轉動而於頂推槽中頂推頂桿，以使頂桿選擇式突 出或收納於徑向滑槽。 1〇 ^上述離心塊之軸向外表面上還固設有一第一離心盤區 段，鍊輪之軸向外表面上還固設有—第二離心盤區段，且 第—離心盤區段係藉由穿過凸緣鎖附孔及輪鎖附孔之一鎖 附件而鎖附固定。 、本發明於減壓裝置之離心塊與鍊輪上分別組設共同構 15成:完整離心盤之二分離部件，且其中第二離心盤區段是 以鎖附方式而固定。因此當鍊輪與減壓裝置組裝於汽缸頭 内後，可接著先進行鍊條掛設於鍊輪上之組裝動作，然後 再進行第二離心盤區段之鎖附。如此一來’鍊條掛設便不 會因離心盤之阻礙而遭遇困難，而引擎内也可同時具有引 2〇 擎減壓及吹漏氣油氣分離之功能。 上述預力構件可為一扭簧。上述第一離心盤區段及/或 第離盤區#又可為圓弧狀，且較佳地，第一離心盤區段 與第二離心盤區段共同形成一圓盤輪廓。第一離心盤區段 可為銲固於離心塊上者。 200907162 面上之一偏心位置 。上述鎖附件可為 上述頂推凸塊可位於減壓心轴端 且頂桿之頂推槽之一頂推面可為平面 螺栓。 5 【實施方式】 本發明為整合有離心盤之減壓裝置，使引擎可同時具 有引擎減壓及吹漏氣油氣分離功能。主要是將離心盤分割 為相互獨立之元件，即第一離心盤區段、及第二離心盤區 段。藉由-習知減壓裝置之鎖附件將第二離心盤區段鎖固 1〇在鍊輪上。第一離心盤區段則可為離心塊之附加件或者與 離心塊一體成形者。 首先參考圖4,其繪示本發明一較佳實施例之減壓裝置 組裝於汽缸頭之剖面圖。圖中顯示汽缸頭4〇内組設有一鍊 輪22、凸輪軸總成21、及減壓裝置之離心塊26，其中離心 15塊26上還固設有一第一離心盤區段31，鍊輪22上鎖附有一 第二離心盤區段32。第一離心盤區段31與第二離心盤區段 32皆具有圓弧輪庵，且共同形成一約略圓盤之外型。 接著參考圖5與圖6，其分別繪示實施例之減壓裝置之 分解圖與組裝圖，其中顯示引擎減壓裝置是組設於一凸輪 20 軸總成21與一鍊輪22上。凸輪軸總成21包括一凸輪軸23、 一閥動凸輪24、及一固定凸緣25。凸輪軸23包括有一軸向 腔室231。 閥動凸輪24套固於凸輪軸23上，且其内部開設有—連 通至軸向腔室231之徑向滑槽241，徑向滑槽241並開口於閥 200907162 動凸輪24之外環面242。固定凸緣25壓配於凸輪轴23上，並 開设有二凸緣鎖附孔25 1，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 5 總成21互相連接固定。 引擎減壓裝置包括一離心塊26、減壓心轴27、一頂桿 28、一預力構件29以及一限位柱35。透過一枢柱33穿過離 心塊26、鍊輪22上之樞孔225，將離心塊26鉚固枢設在鍊輪 22上，離心塊26位置是在以鍊輪22為界相對於閥動凸輪24 10 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的轉動範圍。 離心塊26之軸向外表面上還固設有一第一離心盤區段 3 1 ’鍊輪22之軸向外表面上則固設有一第二離心盤區段 32 ’且第一離心盤區段32是藉由穿過其上二離心盤鎖附孔 15 321、二輪鎖附孔221與222、及二凸緣鎖附孔25 1之二鎖附 件34而鎖附固定在鍊輪22上。鎖附件34使用螺栓，其它等 效鎖附件如螺絲亦適用。 > 本例中’預力構件29使用一扭簧，其套於樞柱33而以 樞柱33為樞轉軸’且一端抵頂於離心塊26，另一端抵頂於 2〇 鍊輪22上所開設之彈簀扣孔224，藉此施予離心塊26 —預 力。 減壓心軸27穿設鍊輪22與凸輪軸23之軸向腔室231，且 其一端面凹設有一徑向延伸之撥動槽272,另一端面則在軸 向上突設有一頂推凸塊271。離心塊26之撥動凸塊261是對 200907162 應伸入撥動槽272中。 頂桿28位於閥動凸輪24之徑向滑槽241中且可滑移。並 且，頂桿28之環面281上凹設有一頂推槽282。頂推槽282之 頂推面283為平面，但不限於此。 5 參考圖7，其繒'示減壓裝置之橫剖面圖。減壓心軸27 之頂推凸塊271是依據減壓心轴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，其中頂桿28之頂推接觸面簡稱為頂推面 Ο 283。本實施例中，頂推凸塊271為一圓柱形凸起，伸入並 10卡合接觸於頂推槽282内，故頂推面283包括上、下二接觸 面。以下將詳細說明本實施例之整合吹漏氣油氣分離之減 壓裝置其作動過程。 圖7所不為引擎停止運轉時，減壓裝置處於作用中之狀 態。此狀態下，離心塊26失去可抵抗預力構件29預力之離 15〜力作用而位於m置。而頂桿28於其頂推面283處受 減壓^軸27之頂推凸塊271之頂推，突出於閥動凸輪24之徑 I 向滑槽241，達到引擎減壓之功效。 而田引擎發動至使離心塊26伴隨鍊輪22轉動所受到之 離心力作用大於扭簧預力時，離心塊财被甩開，即以枢 20柱33為軸相對於鍊輪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⑽27，連帶地也使 減壓〜軸27之頂推凸塊27!於頂推槽282中頂推頂桿之狀 況有所改I。亦即’減壓心軸27之轉動造成頂推凸塊⑺也 產生轉動偏位’也因此偏位之發生而使頂桿^由突出位置 200907162 被頂升而縮入至收納位置。 另一方面，離心盤31與32因為與鍊輪22鎖附固定在一 起，故其伴隨鍊輪22旋轉，藉由離心盤之轉動帶動油氣之 轉動使其中的油滴甩出至擋板42或至汽叙頭壁41 (繪於圖 5 4)上，達成油氣分離效果。 需特別說明的是，此種藉由減壓心軸27轉動頂推頂桿 28之設計視需求而有多種設計變化，例如頂推凸塊η!之偏 心位置、大小等參數皆會影響頂桿28突出之程度，而且也 可以針對其外型輪廓特別設計而達到將其設置於非偏心位 10 置。 為更清楚瞭解離心塊位置狀態之變化，可另外參考圖 8。圖8(a)表示離心塊26未受離心力而只受預力構件29施力 時之狀態，此時減壓裝置發揮作用；圖8(b)表示離心塊％ 同時受離心力與預力構件29預力、且離心力大於預力構件 15 29之預力時之狀態，可明顯看出減壓心軸27受離心塊26之 撥動凸塊（圖未示）撥轉後之變化，此時減壓裝置並不作用。 利用本發明將可達到只需另外製作第一離心盤區段與 第二離心盤區段即可與習知減壓裝置組裝結合，且所使用 的固定第二離心盤之方式為鎖附固定，可避免若事先將離 20 心盤組裝在鍊輪，則會導致之後吊掛鍊條於鍊輪上的組裝 困難性。另外本發明也不須設計變更任何習知零件，因為 是利用原本鍊輪上具有的輪鎖附孔及鎖附件來固定第二離 心盤區段’因此具有極佳的生產成本優勢。 上述實施例僅係為了方便說明而舉例而巳，本發明戶斤 11 200907162 主張之權利範圍自應以申請專利範圍所述為準，而非僅限 於上述實施例。 【圖式簡單說明】 5 圖1係習知減壓裝置組裝於汽缸頭之剖面圖。 圖2係習知減壓裝置之分解圖。 圖3係圖2之組裝圖。 圖4係本發明一較佳實施例之減壓裝置組裝於汽缸頭之剖 面圖。 10圖5係本發明一較佳實施例之減壓裝置分解圖。 圖6係圖5之組裝圖。 圖7係圖6之橫剖面圖。 圖8係圖6之離心塊於不同狀態之平面圖。 扭簧2 減壓心軸4,27 鍊輪6,22 閥動凸輪8,24 撥動凸塊10 頂推凸塊12 固定凸緣14,25 輪鎖附孔221,222 彈簧扣孔224 15 【主要元件符號說明】 插柱1 離心塊3,26 限位柱5 凸輪軸7,23 頂桿9,28 徑向滑槽11 汽缸頭13,40 凸輪軸總成21 限位孔223 12 200907162 樞孔225 徑向滑槽241 凸緣鎖附孔251 頂推凸塊271 頂桿環面281 頂推面283 第一離心盤區段31 離心盤鎖附孔321 鎖附件34 汽缸頭壁41 軸向腔室231 閥動凸輪外環面242 撥動凸塊261 撥動槽272 頂推槽282 預力構件29 第二離心盤區段32 柩柱3 3 限位柱35 擋板42200907162 IX. Description of the Invention: [Technical Field] The present invention relates to a pressure reducing device, and more particularly to an engine pressure reducing device which has an effect of separating oil and gas from a blow-by gas. , soap vehicle, [Prior Art] In the conventional engine cylinder head is equipped with a reading device, the _ axle assembly includes a cam shaft and at least one cam thereon, on the chain cam shaft. The valve actuator is driven by the chain to obtain the rotational mesh force of the crank. A centrifugal disc is fixed on the sprocket, and the centrifugal force acts to cause the Lt to blow off the gas to generate an oil and gas separation effect. 15 Ο In addition, in the conventional internal combustion engine, in order to solve the problem of the large starting impedance of the machine when the crankshaft is ignited and stopped, the so-called engine decompression device is developed. = Cardiac decompression device. Figure 1 is a cross-sectional view showing the assembly of the conventional pressure reducing device in the cylinder head ,3, which shows that the centrifugal block 3 is pivoted on the sprocket-side reduction device. It is disposed inside the cam shaft 7. Referring to Figures 2 and 3, which are respectively a view of a conventional pressure reducing device. In the conventional reduction device, the fixing flange is on the cam shaft 7 and the sprocket 6 is interlocked with each other. In addition, on the centrifugal block _^__, the centrifugal block 3 is subjected to different centrifugal forces depending on the rotational speed of the cam shaft 7. (4) The design of the device is '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 η recessed in the outer annular surface of the valve moving cam 8 is completely received. The state of the radial chute llt, that is, below the valve motion convex = 20 200907162 8 outside the torus ' no decompression at this time. 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 block 3 starts to pivot relative to the sprocket 6 when it is lower than the pre-tension of the pre-force bomb 2, and also causes one of the five core blocks 3 to be moved. Block 1 〇 drives the decompression mandrel 4 to rotate. When the decompression mandrel 4 rotates, the ejector pin 12 on the decompression mandrel 4 is eccentrically set to start pushing the jack 9' to cause the jack 9 to change from the stowed state to the state of the outer ring of the poppet 8 At this time, there is a decompression effect. I The above-mentioned conventional pressure reducing device has a centrifugal block 10 3 in the space of the sprocket 6 side, and a centrifugal disk is attached to the sprocket 6 on the right side, which may cause difficulty in assembly procedures, and the hanging space is caused by the narrow space. When the chain is on the sprocket 6, it is easily blocked by the centrifugal disk. As can be seen from the above, the conventional design cannot take into consideration the function of decompressing the engine and the function of separating the oil and gas from the blow-by gas, resulting in an increase in the consumption of the oil. 15 SUMMARY OF THE INVENTION • The engine decompression device of this watch month is assembled on a camshaft assembly and a sprocket, wherein the camshaft assembly includes a camshaft, a valve cam, and a fixing flange. The camshaft includes an axial chamber, the valve cam is sleeved on the camshaft 20 and includes a pinch chute, the radial chute communicating with the axial chamber and opening 2 the outer camber of the valve cam. The fixing protrusion is disposed on the cam shaft and includes a flange locking hole, and the sprocket includes a wheel lock attachment hole corresponding to the flange locking hole. The engine decompression device includes a centrifugal block, a decompression mandrel, a 200907162, and a top dry. The centrifugal block is pivotally disposed on the sprocket, and comprises a toggle cam/salt pressure mandrel disposed on the sprocket and the axial cavity, wherein one end face is concavely provided with a shifting groove, and the other end face is provided with a pushing convex The block, the toggle block of the centrifugal block is located in the dial groove. 5 ... The pre-stress member - the end abuts against the other end of the centrifugal block against the sprocket to apply a pre-force of the centrifugal block. The ejector rod slides on the radial sliding groove of the valve-moving cam. The 'nozzle groove is recessed on the ring surface of the ejector pin. The urging protrusion pushes the top in the pushing groove according to the rotation of the boring spindle. The rod is such that the jack is selectively protruded or received in the radial chute. 1〇^ The first centrifugal disk segment is further fixed on the axial outer surface of the centrifugal block, and the axial outer surface of the sprocket is further fixed with a second centrifugal disk segment, and the first centrifugal disk segment The lock is fixed by locking the attachment through one of the flange locking hole and the wheel lock attachment hole. In the present invention, the centrifugal block and the sprocket of the decompression device are respectively configured to form a separate component of the complete centrifugal disk, and wherein the second centrifugal disk segment is fixed by locking. Therefore, after the sprocket and the pressure reducing device are assembled in the cylinder head, the assembly operation of the chain hanging on the sprocket can be performed first, and then the second centrifugal disk section can be locked. In this way, the chain hang will not encounter difficulties due to the obstruction of the centrifugal disc, and the engine can also have the functions of decompression and blow-off gas separation. The pre-stress member may be a torsion spring. The first centrifugal disk section and/or the first partial disk section # may be arcuate, and preferably, the first centrifugal disk section and the second centrifugal disk section together form a disk profile. The first centrifugal disk section can be welded to the centrifugal block. 200907162 One of the eccentric positions on the face. The lock attachment may be such that the pushing protrusion can be located at the end of the decompression mandrel and one of the jacking surfaces of the jack of the jack can be a planar bolt. [Embodiment] The present invention is a pressure reducing device incorporating a centrifugal disk, so that the engine can simultaneously have an engine decompression and a blow-off gas-oil separation function. The main purpose is to divide the centrifugal disk into mutually independent components, namely a first centrifugal disk section and a second centrifugal disk section. The second centrifugal disk section is locked to the sprocket by a lock attachment of a conventional pressure reducing device. The first centrifugal disk section can then be an add-on to the centrifugal block or be integrally formed with the centrifugal block. Referring first to Figure 4, there is shown a cross-sectional view of a pressure reducing device assembled to a cylinder head in accordance with a preferred embodiment of the present invention. The figure shows a sprocket 22, a camshaft assembly 21, and a centrifugal block 26 of a pressure reducing device. The first centrifugal disk section 31 is also fixed on the centrifugal 15 block 26, and the sprocket is provided. A second centrifugal disk section 32 is attached to the lock. Both the first centrifugal disk section 31 and the second centrifugal disk section 32 have circular rims and together form an approximate disc shape. Referring to Fig. 5 and Fig. 6, respectively, an exploded view and an assembled view of the pressure reducing device of the embodiment are shown, wherein the engine pressure reducing device is assembled on a cam 20 shaft assembly 21 and a sprocket 22. The camshaft assembly 21 includes a camshaft 23, a valve cam 24, and a fixed flange 25. The camshaft 23 includes an axial chamber 231. The valve cam 24 is sleeved on the cam shaft 23, and is internally provided with a radial sliding groove 241 communicating with the axial chamber 231, and the radial sliding groove 241 is opened to the outside of the valve 200907162. . The fixing flange 25 is press-fitted on the cam shaft 23 and has two flange locking holes 25 1 , 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 lock attachment hole 222 has an arcuate long groove shape. The conventional sprocket 22 is fixedly coupled to the camshaft 5 assembly 21 by means of a locking means. The engine pressure reducing device includes a centrifugal block 26, a pressure reducing mandrel 27, a jack 28, a pre-stress member 29, and a limit post 35. The centrifugal block 26 is riveted and fixed to the sprocket 22 through a pivot post 33 through the pivot block 26 and the pivot hole 225 on the sprocket 22. The position of the centrifugal block 26 is relative to the valve with the sprocket 22 as the boundary. The other side of the cam 24 10 . The limit post 35 is threaded through the stop hole 223 of the sprocket 22 and is riveted to the sprocket 22 to limit the range of rotation of the centrifugal block 26 relative to the sprocket 22. A first centrifugal disk section is also fixed on the axially outer surface of the centrifugal block 26. The axial outer surface of the sprocket 22 is fixed with a second centrifugal disk section 32' and the first centrifugal disk section. 32 is locked and fixed to the sprocket 22 by passing through the upper two centrifugal disc locking holes 15 321 , the two-wheel locking holes 221 and 222 , and the two flange locking holes 25 1 . Bolts are used for the lock attachments 34, and other equivalent lock attachments such as screws are also suitable. > In the present example, the pre-force member 29 uses a torsion spring which is sleeved on the pivot post 33 with the pivot post 33 as the pivot axis and one end abuts against the centrifugal block 26 and the other end abuts against the 2-pin sprocket 22 The opened snap hole 224 is thereby applied to the centrifugal block 26 as a pre-force. The decompression mandrel 27 is disposed with the sprocket 22 and the axial chamber 231 of the camshaft 23, and one end surface is concavely provided with a radially extending dial groove 272, and the other end surface is protruded in the axial direction. Block 271. The toggle projection 261 of the centrifugal block 26 is intended to extend into the dial groove 272 for 200907162. The jack 28 is located in the radial slot 241 of the valve cam 24 and is slidable. Moreover, a top pushing groove 282 is recessed in the toroidal surface 281 of the jack 28 . The pushing surface 283 of the pushing groove 282 is a flat surface, but is not limited thereto. 5 Referring to Figure 7, there is shown a cross-sectional view of the pressure reducing device. 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, the pushing contact surface of the jack 28 is simply referred to as the pushing surface 283. In this embodiment, the pushing protrusion 271 is a cylindrical protrusion that protrudes into and engages with the pushing groove 282. Therefore, the pushing surface 283 includes upper and lower contact surfaces. The operation of the pressure reducing device for integrating the blow-off gas and oil separation in the present embodiment will be described in detail below. In Fig. 7, when the engine is not in operation, the pressure reducing device is in an active state. In this state, the centrifugal block 26 loses its force against the pre-force member 29 preload force and is placed at m. The jack 28 is pushed by the pushing protrusion 271 of the decompression shaft 27 at its pushing surface 283, and protrudes from the diameter I of the valve cam 24 to the chute 241 to achieve the function of decompressing the engine. When the field 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 torsion spring pre-force, the centrifugal block is opened, that is, the rotation of the pivot 20 column 33 relative to the sprocket 22 is started. The dialing protrusion 261 is turned to the decompression (10) 27 in the dialing groove 272 of the decompression mandrel 27, and the decompression of the axis 27 is pushed by the pushing block 27 in the pushing groove 282. The condition of the ejector has been changed. That is, the rotation of the decompression mandrel 27 causes the thrust projection (7) to also generate a rotational offset, and thus the occurrence of the misalignment causes the jack to be lifted up to the storage position by the protruding position 200907162. On the other hand, the centrifugal discs 31 and 32 are locked and fixed together with the sprocket 22, so that as the sprocket 22 rotates, the rotation of the oil and gas drives the rotation of the oil and gas to cause the oil droplets therein to be ejected to the baffle 42 or To the automobile head wall 41 (pictured in Figure 5 4), the oil and gas separation effect is achieved. It should be specially noted that the design of rotating the push-up ejector 28 by the pressure-reducing mandrel 27 has various design changes as needed. For example, the eccentric position and size of the push-pull bump η will affect the ejector. 28 degree of prominence, and can also be specially designed for its outline to achieve its non-eccentric position. For a clearer understanding of the change in the position of the centrifugal block, an additional reference can be made to Figure 8. Fig. 8(a) shows a state in which the centrifugal block 26 is not subjected to centrifugal force and is only biased by the pre-stress member 29, and the decompression device functions at this time; Fig. 8(b) shows the centrifugal block % simultaneously subjected to the centrifugal force and the pre-force member 29 When the pre-force and the centrifugal force are greater than the pre-force of the pre-force member 15 29, it can be clearly seen that the decompression mandrel 27 is changed by the dialing projection of the centrifugal block 26 (not shown). The pressure device does not work. With the invention, it can be achieved that only the first centrifugal disk segment and the second centrifugal disk segment can be separately assembled and assembled with the conventional pressure reducing device, and the fixed second centrifugal disk used is locked and fixed. It can be avoided that if the 20-heart disc is assembled to the sprocket in advance, the assembly of the chain to the sprocket will be difficult to be assembled later. Further, the present invention does not require any design modification of the conventional parts because the second disc portion is fixed by the wheel lock attachment hole and the lock attachment provided on the original sprocket, thus having an excellent production cost advantage. The above embodiments are merely exemplified for convenience of description, and the scope of the claims of the present invention is based on the scope of the patent application, and is not limited to the above embodiments. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view showing a conventional pressure reducing device assembled to a cylinder head. Figure 2 is an exploded view of a conventional pressure reducing device. Figure 3 is an assembled view of Figure 2. Figure 4 is a cross-sectional view showing the assembly of the pressure reducing device of the preferred embodiment of the present invention in a cylinder head. Figure 5 is an exploded view of a pressure reducing device in accordance with a preferred embodiment of the present invention. Figure 6 is an assembled view of Figure 5. Figure 7 is a cross-sectional view of Figure 6. Figure 8 is a plan view of the centrifugal block of Figure 6 in different states. Torsion spring 2 decompression mandrel 4,27 sprocket 6,22 valve cam 8,24 toggle cam 10 pusher lug 12 fixing flange 14,25 wheel lock hole 221,222 spring button hole 224 15 [main components Explanation of symbols] Insert 1 Centrifugal block 3, 26 Limit post 5 Camshaft 7, 23 Plunger 9, 28 Radial chute 11 Cylinder head 13, 40 Camshaft assembly 21 Limit hole 223 12 200907162 Pivot hole 225 diameter To the chute 241, the flange locking hole 251, the pushing protrusion 271, the ejector ring surface 281, the pushing surface 283, the first centrifugal disk section 31, the centrifugal disk locking hole 321, the lock attachment 34, the cylinder head wall 41, the axial chamber 231, the valve Moving cam outer ring surface 242 toggle projection 261 dial groove 272 thrust groove 282 pre-force member 29 second centrifugal disk section 32 mast 3 3 limit post 35 baffle 42