Claims (1)
七、申請專利範圍： 一種具減虔裝置之引擎汽紅頭，包括： 包括有至少二間動凸輪、及複數減愿槽孔. 輪轴驅動件，固定於該凸輪勒而同步轉動. 部 及 —離心塊’抱設於該凸輪轴驅動件，包叙 該離心塊可拖轉於一第一複數驅動 /、 第一位置之間；以 複數減愿構件，設於該凸輪轴内 有—受驅部、及—诘懕你田W 減壓構件包括 於該等驅動㉟ 4 ’該等受驅部分別對應抵頂 槽孔；。，^減㈣用部分別對應收容於該等減麼 動該離心塊位於該第—位置時，該等驅動部帶 之外二使該等減壓作用部不凸出於該等閥動凸輪 該等受驅部而使該等減跑用第時’該等驅動部帶動 廓。 作用。卩凸出於該等閥動凸輪之外 該複數減壓構件包括h H★頭其中’ 一軸體部，該軸m —凸輪式減壓構件，其包括有 ㈣禮杜 端形成為心凸塊型態之該凸輪式 減壓構件之受驅部， ^ 作用部，並依據該轴體邻；=為具有非圓截面之該減壓 出或不凸出於對應該減壓作用部選擇式凸 ^ 功㈣之外磨’且該凸輪式減壓構件 …部所對應之驅動部為_凹槽。 申專利軌圍第1項所述之引擎汽缸頭，其中， 1353408 該複數減壓構件包括有-頂桿式減壓構件，其包括有一轉 轴、以及-頂桿，該轉軸一端形成為凹槽型態之該頂桿式 減壓構件之受驅部，該轉軸另—端形成為偏心設置之__轴 向&塊，該頂桿之環面上凹設有一頂推槽，該頂桿之一端 形成為該減壓作用部，該軸向凸塊位於該頂推槽中並依據 該轉轴之轉動頂推該頂桿，使該減壓仙部選擇式凸出或 不凸出於對應閥動凸輪之外廓，該頂桿式減壓構件之受驅 部所對應之驅動部為一凸塊。VII. Patent application scope: An engine steam red head with a reducing device includes: at least two moving cams and a plurality of reducing slots. The axle driving member is fixed to the cam and synchronously rotates. The centrifugal block is erected on the camshaft driving member, and the centrifugal block can be dragged between a first plurality of driving/first positions; and the plurality of reducing members are disposed in the camshaft to be driven Department, and - 诘懕 your field W decompression members are included in the drive 35 4 'the driven parts correspond to the top slot holes respectively; And the (4) use portion is respectively received in the first position corresponding to the reduction, and the driving portion is disposed outside the driving portion, so that the decompression acting portions do not protrude from the valve cam When the driver is driven, the driver will drive the profile. effect. The plurality of pressure reducing members are protruded from the valve cams, and the plurality of pressure reducing members include a body portion, and the shaft m is a cam type pressure reducing member, which includes (4) a top end formed as a heart bump type The driven portion of the cam type decompression member, ^ acting portion, and depending on the axis body; = is the non-circular cross section of the reduced pressure or does not protrude from the corresponding decompression action portion selection type convex ^ The work (4) is grounded outside and the drive portion corresponding to the cam type pressure reducing member is a groove. The engine cylinder head according to claim 1, wherein the plurality of pressure reducing members comprise a top-rod type pressure reducing member including a rotating shaft and a top rod, wherein one end of the rotating shaft is formed as a groove The driven portion of the ejector-type decompression member of the type, the other end of the rotating shaft is formed as an eccentrically disposed __axial & block, the apex of the ejector is recessed with a pushing groove, the ejector One end is formed as the decompression action portion, and the axial protrusion is located in the pushing groove and pushes the ejector pin according to the rotation of the rotating shaft, so that the decompression fairy is selectively convex or not protruded correspondingly The valve cam has an outer contour, and the driving portion corresponding to the driven portion of the jack-type pressure reducing member is a bump.
4·如申請專利範圍第2項所述之引擎汽缸頭，其中， 該複數減壓構件包括二凸輪式減壓構件。 5 ·如申响專利範圍第1項所述之引擎汽缸頭，更包括 有一限位機構，使該離心塊被限位於該第—位置與該第二 位置之間。 〃 一 6.如申請專利範圍第5項所述之引擎汽缸頭，其中， 該限位機構包括一限位滑槽 該限位滑槽凹 與一限位銷 »又於。玄離〜塊’遠限位銷固定於該凸輪轴驅動件且位於該 限位滑槽中。4. The engine cylinder head of claim 2, wherein the plurality of pressure reducing members comprise two cam type pressure reducing members. 5. The engine cylinder head of claim 1, further comprising a limiting mechanism for restricting the centrifugal block between the first position and the second position. The engine cylinder head according to claim 5, wherein the limit mechanism comprises a limit chute, the limit chute recess and a limit pin » again. The remote limit block is fixed to the camshaft drive member and located in the limit chute.
7.如申叫專利$已圍第i項所述之引擎汽紅頭，更包括 有復位構件’其一端抵頂於該離心塊，另一端抵頂於該 凸輪軸驅動件。 卜8.如中請專利範圍第7項所述之引擎汽虹頭，其中 該復位構件為一扭轉彈簧。 9.如申請專利範圍第！項所述之引擎汽紅頭，兑中 該凸輪軸驅動件為一鍊輪。 八 m 12 1353408 卜/干 h , p ’ y,丨-‘二-—; } ' Ά ， 頂桿式減壓構件可包括有一轉軸、以及一頂桿。轉# 一端形成為凹槽型態之頂桿式減壓構件之受驅部，轉轴另 一端形成為偏心設置之一軸向凸塊。頂桿之環面上凹設有 一頂推槽’頂桿之一端形成為減壓作用部，軸向凸塊位於 頂推槽中並依據轉軸之轉動頂推頂桿，使減壓作用部選擇 式凸出或不凸出於對應之閥動凸輪外廓。頂桿式減壓構件 之受驅部所對應之驅動部為一凸塊。7. The engine steam red head as claimed in claim i, further comprising a reset member' having one end abutting the centrifugal block and the other end abutting the camshaft drive member. 8. The engine steam head according to item 7, wherein the reset member is a torsion spring. 9. If you apply for a patent scope! The engine steam head is described in the item, and the camshaft drive member is a sprocket.八 m 12 1353408 卜/干 h , p y y, 丨-‘二-—; } ' Ά , the ejector-type decompression member may include a rotating shaft, and a ejector rod. One end of the turn # is formed as a driven portion of the ejector type decompression member of the groove type, and the other end of the rotating shaft is formed as an axial projection of one of the eccentric portions. The top surface of the ejector is concavely provided with a pushing groove. One end of the ejector rod is formed as a decompression action portion, and the axial bulge is located in the ejector groove and pushes the ejector rod according to the rotation of the rotating shaft, so that the decompression action portion is selected. Projected or not protruded from the corresponding valve cam profile. The driving portion corresponding to the driven portion of the jack-type pressure reducing member is a bump.
引擎汽缸頭可更包括有一限位機構，使離心塊被限位 於第一位置與第二位置之間。限位機構可包括—限位滑 槽、與一限位銷，限位滑槽凹設於離心塊，限位銷固定於 凸輪轴驅動件且位於限位滑槽中。 引擎汽缸頭可更包括有一復位構件，其一端抵頂於離 心塊’另一端抵頂於凸輪軸驅動件。復位構件可為一扭轉 彈簧。上述凸輪轴驅動件可為一鍊輪。 【實施方式】 參考圖1與圖2，圖1為具減壓裝置之引擎汽缸頭立趙 圖’圖2為減壓裝置分解圖。圖1示出一雙紅引擎之汽缸頭， 有一減壓裝置8安裝於一汽缸頭本體9上。如圖2所示，減壓 裝置8包括一凸輪軸1〇、一凸輪軸驅動件μ、一離心塊μ、 一復位構件20、一第一減壓構件15、一第二減壓構件3〇、 以及一限位機構31。 上述凸輪轴ίο於外週面包括有二閥動凸輪1112、一鎖 固凸緣13，且於轴端面處凹設有二轴向腔室1〇1，1〇2、於外 5 1353408 y^-> r / ' ! 週面亦凹設有二減壓槽孔i〇3，i〇4 ’其中第—轴向腔室1〇1 連通第一減壓槽孔103,第二軸向腔室102連通第二減壓槽 孔104。二閥動凸輪11，12分別對應不同汽缸，而第一減壓槽 孔103開口於閥動凸輪11之外廓11a表面、第二減壓槽孔1〇4 則是鄰接閥動凸輪12 ’當然亦可設計為開口於閥動凸輪12 之外廓12a表面。 凸輪轴驅動件14本例中為一鍊輪，係透過鎖附件a 23 鎖固於鎖固凸緣13而與凸輪軸10呈同步轉動，藉以帶動凸 輪軸10轉動。 離心塊18被一枢柱19穿過而樞設於凸輪軸驅動件14， 其包括有二驅動部181,182。離心塊18可拖轉於一第一位置 與一第二位置之間，第一位置與一第二位置係分別為減壓 裝置不作用與作用時離心塊18之位置。前述復位構件2〇為 一扭轉彈簧，同樣被樞柱19穿過，且一端抵頂於離心塊18， 另一端抵頂於凸輪軸驅動件14，藉此對離心塊18施以一預 力，使離心塊18傾向往第二位置轉動。 第一減壓構件15為一凸輪式減壓構件，包括有一軸體 部150、自軸體部150相反兩端分別延伸之一第一受驅部151 與一第一減壓作用部152。軸體部150位於凸輪轴1〇之第一 軸向腔室101中’第一受驅部151呈一偏心凸塊結構，第一 減壓作用部152具有非圓截面。離心塊18之第一驅動部 為一凹槽結構，上述第一受驅部151即位於此凹槽中受其撥 第二減壓構件30為一頂桿式減壓構件，包括有一轉軸 6 1353408 ，啐/^ /瞭免)¾:芬頁 16、以及一頂桿17。轉軸16容設於凸輪轴10之第二軸向腔 室102 ’轉軸16兩端分別為一第二受驅部16ι '與一軸向凸 塊162’第二受驅部161為一長形凹槽，轴向凸塊162則為偏 心設置。頂桿17環面上凹設有一頂推槽171，頂桿17一端並 形成為一第二減壓作用部172。 上述轴向凸塊162伸入頂推槽171中，依據轉軸16之轉 動頂推頂桿17。而軸向凸塊162於頂推槽171之不同部位頂 推也決定了頂桿17是否滑動凸出於閥動凸輪丨2之外廓 12a。離心塊18之第二驅動部182為一凸塊結構，伸入於上 述凹槽型態之第二受驅部161對其進行撥動。 限位機構31包括一限位滑槽183、與一限位銷21,限位 滑槽183凹設於離心塊18 ,限位銷21穿過限位滑槽183並固 定於凸輪軸驅動件14上，如此可使離心塊μ之轉動被限制 於第一位置與第二位置之間。 圖3為減壓裝置組裝後之部分剖開視圖（未含凸輪轴驅 動件）。由圖中可清楚看出減壓裝置主要是由單一離心塊18 同時帶動二減壓構件，使各自之減壓作用部丨52,172凸出或 不凸出於凸輪軸10上相對應之閥動凸輪n，12之外廓 11 a，12a。以下將分別說明減壓裝置作用與未作用時之機構 運作。 參考圖2與圖4»當引擎運轉時，曲柄軸（圓未示）之旋 轉動力傳遞到凸輪軸驅動件14(鍊輪）、及凸輪軸1〇,離心塊 18也因離心力作用抵抗扭轉彈簧預力而樞轉至第一位置。 此時離心塊18上之二驅動部181，182個別驅動二減壓構件之 7 η ：： ιι -. f 11 jfc n v . i τ · _ - _^.x — ·.- 受驅部151,161，亦即第一減壓構件15會被帶動旋轉而使其 第一減壓作用部152縮入於第一減壓槽孔1〇3，不凸出於閥 動凸輪11之外廓11a;就第二減壓構件30而言，其轉轴16先 被撥動旋轉，其上偏心設置之軸向凸塊162也因此產生位 移，改變頂推頂桿17之部位，使得頂桿π之第二減壓作用 部172於第二減壓槽孔1〇4内滑移而不凸出於閥動凸輪12之 外廓12a ’二減壓構件皆無法推移對應之閥門（圖未示）。如 此減壓裝置便無法發揮減壓功用。 參考圖2與圖5。當引擎低於特定轉速或停止運轉時， 由於凸輪軸驅動件14(鍊輪）、及凸輪軸1〇轉速低或不再轉 動，離心塊18之離心力作用降低，故會被扭轉彈簧預力推 到第二位置》此時離心塊18上之二驅動部181,182以相反於 上述之方向個別驅動二減壓構件之受驅部151，161，亦即第 一減壓構件15會被帶動旋轉而使其第一減壓作用部152凸 出於閥動凸輪11之外廓11a;就第二減壓構件3〇而言，轴向 凸塊162再次產生位移而改變頂推頂桿17之部位，使得頂桿 17之第二減壓作用部172凸出於閥動凸輪12之外廓12a表 面，故二減壓構件皆能推移對應之閥門，減壓裝置發揮減 壓功用》 圖6顯示二減壓構件之減壓作用部152,172分別突出於 凸輪軸10之閥動凸輪外廓，並可看出減壓作用部152推移其 對應閥門26之情形。 圖2中，凸輪軸媒動件14上更可適當地配設一平衡配重 塊（圖未示），藉此與離心塊18及閥動凸輪之不平衡量相互平 1353408 i〇° r I // 衡。此外，第-軸向腔室101所穿設過凸輪軸之一支撐軸承 24之直徑不等於凸輪軸其它支撐軸承直徑。 前述實施例中凸塊/凹槽組合之連動機構，孰知此項技 藝者應當瞭解其型態是可互易的，例如第一受驅部π可換 為一凹槽型態，而對應之第一驅動部28則可換為凸塊型 態，如圖7所示之第二實施例。 參考圖8,為本發明第三實施例。本例主要特色在於， 二減壓構件具有相同構造，也就是都採用第__實施例中凸 輪式減壓構件之結構。同樣地，依靠單一離心塊3ι之轉動 來驅動一受驅部321,331，使二減壓作用部322,332凸出或不 凸出於各自閥動凸輪之外廓。 上述實施例僅係為了方便說明而舉例而已，本發明所 主張之權利範圍自應以申請專利範圍所述為準，而非僅限 於上述實施例。 【圖式簡單說明】 圖1係本發明第一較佳實施例之具減壓裝置之引擎汽缸頭 立體圖。 圖2係圖1中減壓裝置分解圖。 圖3係減壓裝置組裝後之部分剖開視圖。 圖4係離心塊於第一位置時減壓裝置之立體圖。 圖5係離心塊於第二位置時減壓裝置之立體圖。 圖6係減壓裝置作用時剖視圖。 圖7係第二較佳實施例之減壓裝置平面圖。 9 1353408 ^ r ( 1/ 圖8係第三較佳實施例之 【主要元件符號說明】 減壓裝置8 凸輪軸10 第二軸向腔室102 第二減壓槽孔104 外廓 1 la，12a 凸輪軸驅動件14 軸體部150 第一減壓作用部152,322 第二受驅部161,331 頂桿17 第二減壓作用部172,332 第一驅動部181,28 限位滑槽183 復位構件20 鎖附件22,23 閥門26 限位機構31 減壓裝置立體圖。 汽缸頭本體9 第一轴向腔室101 第一減壓槽孔103 閥動凸輪11,12 鎖固凸緣13 第一減壓構件15 第一受驅部151,27,321 轉轴16 軸向凸塊162 頂推槽171 離心塊18,31 第二驅動部182 極柱19 限位銷2 1 支撐軸承24 第二減壓構件30The engine cylinder head may further include a limit mechanism to position the centrifugal block between the first position and the second position. The limiting mechanism may include a limiting slot and a limiting pin, the limiting slot is recessed in the centrifugal block, and the limiting pin is fixed to the camshaft driving component and is located in the limiting sliding slot. The engine cylinder head may further include a reset member having one end abutting against the center of the centrifugal block and the other end abutting against the camshaft drive member. The reset member can be a torsion spring. The camshaft drive member may be a sprocket. [Embodiment] Referring to Fig. 1 and Fig. 2, Fig. 1 is an engine cylinder head with a pressure reducing device. Fig. 2 is an exploded view of the pressure reducing device. Figure 1 shows a cylinder head of a double red engine with a pressure reducing device 8 mounted to a cylinder head body 9. As shown in FIG. 2, the pressure reducing device 8 includes a cam shaft 1〇, a cam shaft driving member μ, a centrifugal block μ, a reset member 20, a first decompression member 15, and a second decompression member 3〇. And a limit mechanism 31. The camshaft ίο includes a two-valve cam 1112 and a locking flange 13 on the outer peripheral surface, and a two-axis chamber 1〇1,1〇2, and an outer 5 1353408 y^ are recessed at the end surface of the shaft. -> r / ' ! The circumference is also recessed with two decompression slots i〇3, i〇4 'where the first-axial chamber 1〇1 communicates with the first decompression slot 103, the second axial cavity The chamber 102 communicates with the second reduced pressure slot 104. The two valve moving cams 11, 12 respectively correspond to different cylinders, and the first pressure reducing groove 103 is open to the surface of the outer surface 11a of the valve moving cam 11, and the second pressure reducing hole 1〇4 is adjacent to the valve moving cam 12' It is also designed to open on the surface of the outer periphery 12a of the valve cam 12. The camshaft drive member 14 is a sprocket in this example, which is locked to the lock flange 13 via the lock attachment a 23 to rotate synchronously with the camshaft 10, thereby driving the camshaft 10 to rotate. The centrifugal block 18 is pivoted through a pivot post 19 and is pivotally mounted to the camshaft drive member 14 and includes two drive portions 181, 182. The centrifugal block 18 can be dragged between a first position and a second position, the first position and the second position being the positions of the centrifugal block 18 when the pressure reducing device is inactive and acting, respectively. The reset member 2 is a torsion spring, which is also passed through by the pivot post 19, and one end abuts against the centrifugal block 18, and the other end abuts against the camshaft drive member 14, thereby applying a pre-force to the centrifugal block 18. The centrifugal block 18 is inclined to rotate toward the second position. The first decompression member 15 is a cam type decompression member, and includes a shaft body portion 150, and a first driven portion 151 and a first decompressing portion 152 extending from opposite ends of the shaft portion 150, respectively. The shaft portion 150 is located in the first axial chamber 101 of the cam shaft 1'. The first driven portion 151 has an eccentric convex structure, and the first pressure reducing portion 152 has a non-circular cross section. The first driving portion of the centrifugal block 18 is a groove structure, and the first driven portion 151 is located in the groove, and the second pressure reducing member 30 is a ejector type pressure reducing member, including a rotating shaft 6 1353408. , 啐 / ^ / free) 3⁄4: Fen page 16, and a pole 17 . The rotating shaft 16 is disposed on the second axial chamber 102 of the camshaft 10. The two ends of the rotating shaft 16 are respectively a second driven portion 16 ι ' and an axial projection 162 ′. The second driven portion 161 is an elongated concave portion. The slots and axial projections 162 are eccentrically disposed. A pushing groove 171 is recessed on the annular surface of the ejector pin 17, and one end of the ejector pin 17 is formed as a second decompressing action portion 172. The axial projection 162 extends into the thrust groove 171 to push the plunger 17 in accordance with the rotation of the rotating shaft 16. The pushing of the axial projection 162 at different portions of the thrust groove 171 also determines whether the ram 17 slides out of the outer contour 12a of the valve cam 丨2. The second driving portion 182 of the centrifugal block 18 has a convex structure, and the second driven portion 161 which protrudes into the above-mentioned groove type is slid. The limiting mechanism 31 includes a limiting slot 183 and a limiting pin 21 . The limiting slot 183 is recessed in the centrifugal block 18 . The limiting pin 21 passes through the limiting slot 183 and is fixed to the camshaft driving component 14 . In this way, the rotation of the centrifugal block μ can be restricted between the first position and the second position. Figure 3 is a partially cutaway view of the pressure reducing device after assembly (without the camshaft drive). It can be clearly seen from the figure that the pressure reducing device mainly drives the two pressure reducing members simultaneously by the single centrifugal block 18, so that the respective pressure reducing action portions 52, 172 protrude or do not protrude from the corresponding valve moving cam on the cam shaft 10. n, 12 outer contours 11 a, 12a. The operation of the decompression device and the operation of the non-acting mechanism will be separately described below. Referring to Figures 2 and 4, when the engine is running, the rotational power of the crankshaft (circle not shown) is transmitted to the camshaft drive member 14 (sprocket) and the camshaft 1〇, and the centrifugal block 18 also resists the torsion spring due to the centrifugal force. Pivoted to the first position. At this time, the two driving portions 181, 182 on the centrifugal block 18 individually drive the 7 η :: ιι -. f 11 jfc nv . i τ · _ - _^.x — ·-- the driven portion 151, 161 of the two decompression members. That is, the first decompression member 15 is rotated to cause the first decompression action portion 152 to retract into the first decompression slot 1 〇 3, not protruding from the outer contour 11a of the valve cam 11; In the case of the two decompression members 30, the rotating shaft 16 is first slidably rotated, and the axially convex 162 disposed on the eccentric portion thereof is also displaced, and the position of the ejector pin 17 is changed, so that the second π of the ejector pin is reduced. The pressure acting portion 172 slides in the second pressure reducing groove 1〇4 without protruding from the outer periphery of the valve cam 12a. The two pressure reducing members cannot move the corresponding valve (not shown). Therefore, the decompression device cannot perform the decompression function. Refer to Figures 2 and 5. When the engine is lower than the specific speed or stops running, the centrifugal force of the centrifugal block 18 is reduced due to the low rotation speed of the camshaft drive member 14 (sprocket) and the camshaft 1 不再, and the centrifugal force is reduced by the torsion spring. In the second position, at this time, the two driving portions 181, 182 on the centrifugal block 18 individually drive the driven portions 151, 161 of the two decompression members in the opposite directions, that is, the first decompression member 15 is rotated. The first decompression action portion 152 protrudes from the outer contour 11a of the valve cam 13; in the case of the second decompression member 3〇, the axial projection 162 is again displaced to change the position of the jacking rod 17, so that The second decompression action portion 172 of the jack 17 protrudes from the surface of the outer periphery 12a of the valve cam 12, so that the two decompression members can all move the corresponding valve, and the decompression device functions as a decompression function. The decompression action portions 152, 172 of the members respectively protrude from the valve cam profile of the cam shaft 10, and it can be seen that the decompression action portion 152 is displaced by its corresponding valve 26. In FIG. 2, a balance weight (not shown) can be appropriately disposed on the camshaft medium 14 to thereby offset the imbalance between the centrifugal block 18 and the valve cam by 1353408 i〇° r I / / Balance. Further, the diameter of one of the support shafts 24 through which the first axial chamber 101 is passed through the cam shaft is not equal to the other support bearing diameter of the cam shaft. In the foregoing embodiment, the linkage mechanism of the bump/groove combination, it is known to those skilled in the art that the type is reciprocally easy, for example, the first driven portion π can be replaced by a groove type, and the corresponding The first driving portion 28 can be replaced with a bump type, as shown in the second embodiment shown in FIG. Referring to Figure 8, a third embodiment of the present invention is shown. The main feature of this example is that the two decompression members have the same configuration, that is, the structure of the cam-type decompression member in the first embodiment is employed. Similarly, a driven portion 321 , 331 is driven by the rotation of a single centrifugal block 3 to cause the two decompression action portions 322 , 332 to protrude or not protrude from the respective valve cam profile. The above-described embodiments are merely examples for the convenience of the description, and the scope of the claims is intended to be limited by the scope of the claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of an engine cylinder head with a pressure reducing device according to a first preferred embodiment of the present invention. Figure 2 is an exploded view of the pressure reducing device of Figure 1. Fig. 3 is a partially cutaway view showing the assembly of the pressure reducing device. Figure 4 is a perspective view of the pressure reducing device when the centrifugal block is in the first position. Figure 5 is a perspective view of the pressure reducing device when the centrifugal block is in the second position. Figure 6 is a cross-sectional view showing the action of the pressure reducing device. Figure 7 is a plan view of the pressure reducing device of the second preferred embodiment. 9 1353408 ^ r ( 1 / Figure 8 is a description of the main components in the third preferred embodiment) Pressure reducing device 8 Camshaft 10 Second axial chamber 102 Second pressure reducing hole 104 Outline 1 la, 12a Camshaft drive member 14 Shaft portion 150 First decompression action portion 152, 322 Second driven portion 161, 331 Plunger 17 Second decompression action portion 172, 332 First drive portion 181, 28 Limit chute 183 Reset member 20 Lock attachment 22 23 valve 26 limit mechanism 31 perspective view of the pressure reducing device. cylinder head body 9 first axial chamber 101 first pressure reducing groove 103 valve moving cam 11, 12 locking flange 13 first pressure reducing member 15 first Driven part 151, 27, 321 Rotary shaft 16 Axial lug 162 Pushing groove 171 Centrifugal block 18, 31 Second drive part 182 Pole 19 Limit pin 2 1 Support bearing 24 Second decompression member 30