TWI611094B - Engine and vehicle - Google Patents

Abstract

於本發明中，自凸輪軸之軸線方向觀察，將通過凸輪軸之旋轉中心與配重體之旋轉中心之直線設為縱軸。將與縱軸正交且通過凸輪軸之旋轉中心之直線設為橫軸。將平行於縱軸之方向中之自凸輪軸之旋轉中心朝向配重體之旋轉中心之方向設為第1縱方向。將平行於橫軸之方向中之一者設為第1橫方向。自凸輪軸之軸線方向觀察，配重體之重心配置於第1區域。第1區域相對於橫軸位於第1縱方向，並且相對於縱軸位於第1橫方向。配重體包含第1部分，自凸輪軸之軸線方向觀察，該第1部分配置於第1區域。於閉合狀態下，第1部分包含第1突出部，自凸輪軸之軸線方向觀察，該第1突出部朝較軸承之外周面更靠外側突出。 In the present invention, when viewed from the axial direction of the cam shaft, a straight line passing through the rotation center of the cam shaft and the rotation center of the weight body is set as the vertical axis. A straight line that is orthogonal to the vertical axis and passes through the center of rotation of the cam shaft is taken as the horizontal axis. In the direction parallel to the vertical axis, the direction from the rotation center of the cam shaft toward the rotation center of the weight body is set as the first vertical direction. One of the directions parallel to the horizontal axis is set as the first horizontal direction. When viewed from the axial direction of the camshaft, the center of gravity of the weight body is arranged in the first area. The first region is located in the first vertical direction with respect to the horizontal axis and is located in the first horizontal direction with respect to the vertical axis. The weight body includes a first portion, and the first portion is disposed in the first region when viewed from the axial direction of the camshaft. In the closed state, the first portion includes a first protruding portion. When viewed from the axial direction of the camshaft, the first protruding portion protrudes further outward than the outer peripheral surface of the bearing.

Description

引擎及車輛 Engines and vehicles

本發明係關於一種具備減壓(decompression)機構(以下稱為「減壓機構」)之引擎及車輛。 The present invention relates to an engine and a vehicle having a decompression mechanism (hereinafter referred to as a "decompression mechanism").

當使引擎起動時，需要藉由外力使引擎旋轉直至起動結束。例如存在利用起動馬達旋轉者，或利用腳踩起動機旋轉者。另一方面，於引擎之壓縮步驟中，汽缸內之空氣被壓縮，故而旋轉之阻力增加。為了減少此種阻力，已知有用以於藉由外力使引擎旋轉時之壓縮步驟中使汽缸內之壓力減少之減壓機構。 When starting the engine, it is necessary to rotate the engine by external force until the start is completed. For example, there are those who use a starter motor to rotate, or those who use a foot starter to rotate. On the other hand, during the compression step of the engine, the air in the cylinder is compressed, so the resistance to rotation increases. In order to reduce such resistance, a pressure reducing mechanism is known which is used to reduce the pressure in the cylinder in a compression step when the engine is rotated by an external force.

例如日本專利特開2008-128171號所揭示之引擎之減壓機構具有減壓凸輪，該減壓凸輪係藉由配重體之旋轉而切換成作動狀態及解除狀態。該減壓機構支持於凸輪鏈條之鏈輪。因此，存在包含減壓機構之凸輪軸於軸向上變大之問題。 For example, the decompression mechanism of the engine disclosed in Japanese Patent Laid-Open No. 2008-128171 has a decompression cam, and the decompression cam is switched to an activated state and a released state by the rotation of the weight body. The decompression mechanism is supported on a sprocket of a cam chain. Therefore, there is a problem that the cam shaft including the pressure reducing mechanism becomes large in the axial direction.

於日本專利特開2008-64083號所揭示之引擎中，減壓機構配置於凸輪軸之兩端部之間之位置。減壓機構具有配重體及減壓凸輪，配重體藉由支持軸可相對於凸輪軸旋轉地受到支持。減壓凸輪與配重體藉由銷而連接，配重體以支持軸為中心旋轉，藉此，銷使減壓凸輪旋轉。 In the engine disclosed in Japanese Patent Laid-Open No. 2008-64083, the pressure reducing mechanism is disposed between the two ends of the camshaft. The decompression mechanism includes a weight body and a decompression cam, and the weight body is rotatably supported relative to the cam shaft via a support shaft. The decompression cam and the weight body are connected by a pin, and the weight body rotates around the support shaft, whereby the pin rotates the decompression cam.

於日本專利特開2008-64083號之減壓機構中，當凸輪軸不旋轉時，配重體藉由回復彈簧之作用而保持於閉合之狀態。於配重體閉合之狀態下，減壓凸輪成為可對排氣閥進行作用之狀態。因此，當引擎 起動時，減壓凸輪對排氣閥進行作用而打開排氣閥，藉此使汽缸內之壓力減少。 In the decompression mechanism of Japanese Patent Laid-Open No. 2008-64083, when the camshaft does not rotate, the weight body is kept closed by the action of a return spring. When the weight body is closed, the decompression cam is in a state capable of acting on the exhaust valve. So when the engine When starting, the pressure reducing cam acts on the exhaust valve and opens the exhaust valve, thereby reducing the pressure in the cylinder.

若凸輪軸旋轉，則配重體因受到離心力而繞支持軸旋轉。若凸輪軸之旋轉速度上升至某設定旋轉速度以上，則離心力超過回復彈簧之彈力，藉此使配重體成為打開之狀態。於配重體打開之狀態下，減壓凸輪成為不對排氣閥進行作用之狀態。 When the cam shaft rotates, the weight body rotates around the support shaft due to the centrifugal force. If the rotation speed of the camshaft rises above a certain set rotation speed, the centrifugal force exceeds the elastic force of the return spring, thereby bringing the weight body into an open state. When the weight body is opened, the decompression cam is in a state where it does not act on the exhaust valve.

於日本專利特開2008-64083號之減壓機構中，可有效利用凸輪軸之兩端之間之空間。因此，與於凸輪軸之外配置減壓機構之情形相比，有時能夠使包含減壓機構之凸輪軸於軸向上精簡化。然而，本案之發明者進行研究後發現，於如日本專利特開2008-64083號所記載般之先前技術之引擎中，存在當起動時減壓機構不作動而使起動性之改善並不充分之情況。 In the pressure reducing mechanism of Japanese Patent Laid-Open No. 2008-64083, the space between the two ends of the camshaft can be effectively used. Therefore, compared with a case where a pressure reducing mechanism is provided outside the camshaft, the cam shaft including the pressure reducing mechanism may be simplified in the axial direction. However, the inventor of the present case conducted research and found that, in the engine of the prior art as described in Japanese Patent Laid-Open No. 2008-64083, there is an inadequate improvement in the startability of the decompression mechanism when the start is not activated. Happening.

本發明之課題在於提供一種可提高減壓機構之起動性之引擎及車輛。 An object of the present invention is to provide an engine and a vehicle capable of improving the startability of a decompression mechanism.

本案之發明者對先前技術之引擎中當起動時減壓不作動之原因進行了驗證。結果可知，存在當引擎起動時，配重體已經成為打開之狀態之情況。亦即，可知，存在當引擎停止時，配重體並未閉合而以打開之狀態維持之情況。 The inventors of this case have verified the reason why the decompression does not work when starting in the engine of the prior art. As a result, it was found that there may be a case where the weight body has been opened when the engine is started. That is, it can be seen that when the engine is stopped, there is a case where the weight body is not closed but maintained in an opened state.

根據本案之發明者之研究，認為其原因在於回復彈簧之彈力較弱。而且，彈力變弱之原因在於，藉由將減壓機構配置於凸輪軸之兩端之間，而使配重體變小。即，於日本專利特開2008-64083號之減壓機構中，減壓機構係配置於凸輪軸之兩端之間，故而與日本專利特開2008-128171號之減壓機構相比，配置之限制較大。因此，於日本專 利特開2008-64083號之減壓機構中，需要使配重體小於日本專利特開2008-128171號之減壓機構中之配重體。 According to the research of the inventor of this case, it is thought that the reason is that the elastic force of the return spring is weak. Further, the reason why the elastic force is weakened is that the weight body is made smaller by disposing the decompression mechanism between both ends of the cam shaft. That is, in the decompression mechanism of Japanese Patent Laid-Open No. 2008-64083, the decompression mechanism is disposed between both ends of the cam shaft, so compared with the decompression mechanism of Japanese Patent Laid-Open No. 2008-128171, The restrictions are greater. Therefore, in Japan In the decompression mechanism of Japanese Patent Laid-Open No. 2008-64083, it is necessary to make the weight body smaller than that in the decompression mechanism of Japanese Patent Laid-Open No. 2008-128171.

若配重體變小，則配重體之質量變小。若旋轉速度相同，則配重體之質量越小，作用至配重體之離心力之大小越小。因此，於用以將配重體設為打開狀態之設定旋轉速度下，作用至配重體之離心力變小。因此，需要亦使彈力減小。 If the weight body becomes smaller, the weight of the weight body becomes smaller. If the rotation speed is the same, the smaller the mass of the weight, the smaller the centrifugal force acting on the weight. Therefore, the centrifugal force acting on the weight body becomes smaller at the set rotation speed for setting the weight body to the open state. Therefore, it is necessary to also reduce the elastic force.

然而，配重體之位置係根據凸輪軸之旋轉之相位而變化。亦存在配重體之打開方向與重力方向一致之狀態下凸輪軸停止之情況。本案之發明者查明：此時，因使彈力減小，而使作用至配重體之重力所引起之力矩變得大於彈力，其結果，配重體成為打開狀態。 However, the position of the weight body changes according to the phase of the rotation of the camshaft. There is also a case where the camshaft stops when the opening direction of the weight body coincides with the direction of gravity. The inventor of the present case ascertained that at this time, due to the reduction of the elastic force, the moment caused by the gravity acting on the weight body becomes larger than the elastic force, and as a result, the weight body is opened.

認為，為了防止如上所述般之現象，而增大彈力，但若彈力增大，則打開配重體之設定旋轉速度上升。設定旋轉速度之上升會成為產生噪音之原因，故而不佳。 It is considered that the elastic force is increased in order to prevent the phenomenon as described above, but if the elastic force is increased, the set rotation speed of the open weight is increased. Increasing the setting rotation speed is a cause of noise, so it is not good.

本發明之一態樣之引擎具備汽缸頭、排氣閥、閥動機構、凸輪軸、軸承、及減壓機構。排氣閥收納於汽缸頭。閥動機構使排氣閥打開及閉合。凸輪軸藉由與閥動機構接觸，而驅動閥動機構。軸承將凸輪軸可旋轉地支持於汽缸頭。減壓機構配置於凸輪軸之軸線方向上之兩端部之間。 An aspect of the invention is an engine including a cylinder head, an exhaust valve, a valve operating mechanism, a camshaft, a bearing, and a pressure reducing mechanism. The exhaust valve is housed in the cylinder head. The valve action mechanism opens and closes the exhaust valve. The camshaft drives the valve mechanism by being in contact with the valve mechanism. The bearing rotatably supports the camshaft to the cylinder head. The decompression mechanism is disposed between both end portions in the axial direction of the cam shaft.

減壓機構包含配重體、回復彈簧、及減壓凸輪。配重體相對於凸輪軸可於閉合狀態與打開狀態之間旋轉地受到支持。回復彈簧以使配重體自打開狀態恢復至閉合狀態之方式對該配重體彈壓。減壓凸輪係以如下方式而設置，即，當配重體為閉合狀態時，與閥動機構接觸，當配重體為打開狀態時，不與閥動機構接觸。 The decompression mechanism includes a weight body, a return spring, and a decompression cam. The weight body is rotatably supported with respect to the camshaft between a closed state and an open state. The return spring urges the weight body so that the weight body returns from the open state to the closed state. The decompression cam is provided in such a manner that, when the weight body is in a closed state, it is in contact with the valve mechanism, and when the weight body is in an open state, it is not in contact with the valve mechanism.

自凸輪軸之軸線方向觀察，將通過凸輪軸之旋轉中心與配重體之旋轉中心之直線設為縱軸。將與縱軸正交且通過凸輪軸之旋轉中心之直線設為橫軸。將平行於縱軸之方向中之自凸輪軸之旋轉中心朝向 配重體之旋轉中心之方向設為第1縱方向。將平行於橫軸之方向中之一者設為第1橫方向。 As viewed from the axis direction of the camshaft, a straight line passing through the rotation center of the camshaft and the rotation center of the weight body is set as the vertical axis. A straight line that is orthogonal to the vertical axis and passes through the center of rotation of the cam shaft is taken as the horizontal axis. Orient the center of rotation of the camshaft in a direction parallel to the longitudinal axis The direction of the rotation center of the weight is set to the first vertical direction. One of the directions parallel to the horizontal axis is set as the first horizontal direction.

自凸輪軸之軸線方向觀察，配重體之重心配置於第1區域。第1區域相對於橫軸位於第1縱方向，並且相對於縱軸位於第1橫方向。配重體包含第1部分，自凸輪軸之軸線方向觀察，該第1部分配置於第1區域。於閉合狀態下，自凸輪軸之軸線方向觀察，第1部分包含較軸承之外周面更朝外側突出之第1突出部。 When viewed from the axial direction of the camshaft, the center of gravity of the weight body is arranged in the first area. The first region is located in the first vertical direction with respect to the horizontal axis and is located in the first horizontal direction with respect to the vertical axis. The weight body includes a first portion, and the first portion is disposed in the first region when viewed from the axial direction of the camshaft. In the closed state, when viewed from the axial direction of the camshaft, the first portion includes a first protruding portion that protrudes more outwardly than the outer peripheral surface of the bearing.

於本態樣之引擎中，配重體中之位於第1區域之第1部分之第1突出部朝較軸承之外周面更靠外側突出。藉此，與第1部分不突出之情形相比，可使配重體之重心遠離凸輪軸之旋轉中心。因此，若凸輪軸之旋轉速度相同，則施加至配重體之離心力變大。藉此，可增大彈力，故而無需使設定轉數上升，便可抑制重力所引起之配重體之打開。 In the engine of this aspect, the first protruding portion in the first portion of the weight body located in the first region protrudes further outward than the outer peripheral surface of the bearing. As a result, the center of gravity of the weight body can be kept away from the center of rotation of the cam shaft, as compared with the case where the first part does not protrude. Therefore, if the rotation speed of the cam shaft is the same, the centrifugal force applied to the weight body becomes large. Thereby, the elastic force can be increased, so that the opening of the weight body caused by gravity can be suppressed without increasing the set number of revolutions.

較佳為，配重體進而包含第2部分。自凸輪軸之軸線方向觀察，第2部分配置於第2區域。第2區域相對於橫軸位於第2縱方向，並且相對於縱軸位於第1橫方向。第2縱方向係與第1縱方向相反之方向。自凸輪軸之軸線方向觀察，第2部分之外周面位於較軸承之外周面更靠內側處。 Preferably, the weight body further includes a second portion. When viewed from the axial direction of the camshaft, the second portion is disposed in the second region. The second region is located in the second vertical direction with respect to the horizontal axis, and is located in the first horizontal direction with respect to the vertical axis. The second longitudinal direction is a direction opposite to the first longitudinal direction. Viewed from the axial direction of the camshaft, the outer peripheral surface of the second part is located more inward than the outer peripheral surface of the bearing.

於此情形時，可使配重體之重心進一步遠離凸輪軸之旋轉中心。又，與第2部分之外周面位於較軸承之外周面更靠外側之情形相比，可使配重體之重心位置靠近配重體之旋轉中心。因此，可減小作用至配重體之重力所引起之力矩。因此，可抑制重力所引起之配重體之打開。藉此，易於避免當引擎起動時配重體打開之狀態，故而可提高引擎之起動性。 In this case, the center of gravity of the weight body can be further away from the center of rotation of the camshaft. Moreover, compared with the case where the outer peripheral surface of the second part is located further outside than the outer peripheral surface of the bearing, the position of the center of gravity of the weight body can be brought closer to the center of rotation of the weight body. Therefore, the moment caused by the gravity acting on the weight can be reduced. Therefore, the weight body can be prevented from being opened by gravity. Thereby, it is easy to avoid the state where the weight body is opened when the engine is started, so the startability of the engine can be improved.

第2部分亦可包含第2突出部，自凸輪軸之軸線方向觀察，該第2突出部較軸承之外周面更朝外側突出。第1突出部之體積大於第2突出 部之體積。 The second part may also include a second protruding portion, and the second protruding portion projects further outward than the outer peripheral surface of the bearing when viewed from the axial direction of the camshaft. The volume of the first protrusion is larger than that of the second protrusion Department of volume.

於此情形時，可使配重體之重心進一步遠離凸輪軸之旋轉中心。又，與第2突出部之體積大於第1突出部之體積之情形相比，可使配重體之重心位置靠近配重體之旋轉中心。因此，可減小作用至配重體之重力所引起之力矩。因此，可抑制重力所引起之配重體之打開。藉此，易於避免當引擎起動時配重體打開之狀態，故而可提高引擎之起動性。 In this case, the center of gravity of the weight body can be further away from the center of rotation of the camshaft. Moreover, compared with the case where the volume of the second protrusion is larger than the volume of the first protrusion, the position of the center of gravity of the weight body can be brought closer to the center of rotation of the weight body. Therefore, the moment caused by the gravity acting on the weight can be reduced. Therefore, the weight body can be prevented from being opened by gravity. Thereby, it is easy to avoid the state where the weight body is opened when the engine is started, so the startability of the engine can be improved.

較佳為，凸輪軸之軸線方向上之第1突出部之最大厚度大於凸輪軸之軸線方向上之第2部分之最大厚度。於此情形時，可使配重體之重心進一步遠離凸輪軸之旋轉中心。 Preferably, the maximum thickness of the first protruding portion in the axial direction of the cam shaft is larger than the maximum thickness of the second portion in the axial direction of the cam shaft. In this case, the center of gravity of the weight body can be further away from the center of rotation of the camshaft.

較佳為，配重體進而包含第3部分。自凸輪軸之軸線方向觀察，第3部分配置於第3區域。第3區域相對於橫軸位於第2縱方向，並且相對於縱軸位於第2橫方向。第2橫方向係與第1橫方向相反之方向。自凸輪軸之軸線方向觀察，第3部分之外周面位於較軸承之外周面更靠內側處。於此情形時，與自凸輪軸之軸線方向觀察，第3部分之外周面位於較軸承之外周面更靠外側之情形相比，可使配重體之重心進一步遠離凸輪軸之旋轉中心。 Preferably, the weight body further includes a third portion. When viewed from the axial direction of the camshaft, the third portion is disposed in the third region. The third region is located in the second vertical direction with respect to the horizontal axis, and is located in the second horizontal direction with respect to the vertical axis. The second lateral direction is a direction opposite to the first lateral direction. Viewed from the axial direction of the camshaft, the outer peripheral surface of the third portion is located more inward than the outer peripheral surface of the bearing. In this case, the center of gravity of the weight body can be further away from the center of rotation of the cam shaft, as compared with the case where the outer peripheral surface of the third portion is located further outside than the outer peripheral surface of the bearing when viewed from the axial direction of the cam shaft.

第3部分亦可包含第3突出部，自凸輪軸之軸線方向觀察，該第3突出部較軸承之外周面更朝外側突出。第1突出部之體積大於第3突出部之體積。於此情形時，與第3突出部之體積大於第1突出部之體積之情形相比，可使配重體之重心進一步遠離凸輪軸之旋轉中心。 The third part may further include a third protruding portion, and the third protruding portion projects further outward than the outer peripheral surface of the bearing when viewed from the axial direction of the camshaft. The volume of the first protrusion is larger than the volume of the third protrusion. In this case, compared with the case where the volume of the third protrusion is larger than the volume of the first protrusion, the center of gravity of the weight body can be further away from the center of rotation of the cam shaft.

較佳為，凸輪軸之軸線方向上之第1突出部之最大厚度大於凸輪軸之軸線方向上之第3部分之最大厚度。於此情形時，與第1突出部之最大厚度小於第3部分之最大厚度之情形相比，可使配重體之重心進一步遠離凸輪軸之旋轉中心。 Preferably, the maximum thickness of the first protruding portion in the axial direction of the cam shaft is larger than the maximum thickness of the third portion in the axial direction of the cam shaft. In this case, compared with the case where the maximum thickness of the first protruding portion is smaller than the maximum thickness of the third portion, the center of gravity of the weight body can be further away from the center of rotation of the cam shaft.

較佳為，自凸輪軸之軸線方向觀察，第1突出部包含：較近之部 分，其於軸承之周向上，較無第1突出部時之配重體之重心之位置更靠近配重體之旋轉中心；及較遠之部分，其於軸承之周向上，較無第1突出部時之配重體之重心之位置更遠離配重體之旋轉中心，且較近之部分大於較遠之部分。於此情形時，與較遠之部分大於較近之部分之情形相比，可使配重體之重心進一步靠近配重體之旋轉中心。 Preferably, when viewed from the axial direction of the camshaft, the first protruding portion includes: a closer portion In the circumferential direction of the bearing, it is closer to the center of rotation of the weight body than in the position of the center of gravity of the weight body when there is no first protrusion; and in the farther portion, it is less in the circumferential direction of the bearing than the first The position of the center of gravity of the weight body at the time of the protrusion is further away from the center of rotation of the weight body, and the closer part is larger than the farther part. In this case, the center of gravity of the weight body can be brought closer to the center of rotation of the weight body compared to the case where the farther part is larger than the closer part.

較佳為，配重體包含樞銷支持部。減壓機構進而包含安裝於樞銷支持部之樞銷。配重體經由樞銷可相對於凸輪軸旋轉地受到支持。凸輪軸之軸線方向上之第1突出部之厚度大於凸輪軸之軸線方向上之樞銷支持部之厚度。 Preferably, the weight body includes a pivot pin support portion. The decompression mechanism further includes a pivot pin mounted on the pivot pin support portion. The weight body is rotatably supported relative to the cam shaft via a pivot pin. The thickness of the first protruding portion in the axis direction of the cam shaft is greater than the thickness of the pivot pin support portion in the axis direction of the cam shaft.

於此情形時，與第1突出部之厚度小於樞銷支持部之厚度之情形相比，可使配重體之重心遠離凸輪軸之旋轉中心。 In this case, compared with the case where the thickness of the first protruding portion is smaller than the thickness of the pivot pin support portion, the center of gravity of the weight body can be kept away from the center of rotation of the cam shaft.

較佳為，引擎進而具備曲軸、及凸輪鏈條。汽缸頭包含支持軸承之軸承支持孔。軸承支持孔包含可使第1突出部通過之凹部。凹部之至少一部分位於相對於軸承支持孔之中心與曲軸為相反的一側。 Preferably, the engine further includes a crankshaft and a cam chain. The cylinder head contains bearing support holes to support the bearings. The bearing support hole includes a recessed portion through which the first protruding portion can pass. At least a part of the recess is located on the side opposite to the crankshaft with respect to the center of the bearing support hole.

於此情形時，當將凸輪軸、減壓機構、及軸承一體地安裝至汽缸頭時，第1突出部可通過凹部。藉此，可避免第1突出部干涉軸承支持孔。另一方面，若於軸承支持孔設置有凹部，則於凹部並未支持有軸承，故而有軸承之支持強度之降低之顧慮。然而，凹部之至少一部分位於相對於軸承支持孔之中心與曲軸為相反的一側。因此，可抑制較大地承受來自曲軸之負載之軸承支持孔之曲軸側的部分之支持強度之降低。 In this case, when the camshaft, the pressure reducing mechanism, and the bearing are integrally mounted to the cylinder head, the first protruding portion may pass through the recessed portion. This prevents the first protrusion from interfering with the bearing support hole. On the other hand, if a recess is provided in the bearing support hole, the bearing is not supported in the recess, so there is a concern that the support strength of the bearing is reduced. However, at least a part of the recess is located on the side opposite to the crankshaft with respect to the center of the bearing support hole. Therefore, it is possible to suppress a decrease in the support strength of the portion on the crankshaft side of the bearing support hole that greatly receives the load from the crankshaft.

本發明之另一態樣之車輛具備上述引擎。 A vehicle according to another aspect of the present invention includes the engine described above.

根據本發明，可提供一種能夠提高減壓機構之起動性之引擎及車輛。 According to the present invention, it is possible to provide an engine and a vehicle capable of improving startability of a decompression mechanism.

1‧‧‧車輛 1‧‧‧ vehicle

2‧‧‧車輛本體 2‧‧‧vehicle body

2a‧‧‧平坦腳踏板 2a‧‧‧flat pedal

3‧‧‧前輪 3‧‧‧ front wheel

4‧‧‧後輪 4‧‧‧ rear wheel

5‧‧‧把手 5‧‧‧handle

6‧‧‧座部 6‧‧‧ seat

7‧‧‧引擎 7‧‧‧ Engine

8‧‧‧變速箱 8‧‧‧ Gearbox

11‧‧‧曲軸 11‧‧‧ crankshaft

12‧‧‧曲軸箱 12‧‧‧ crankcase

13‧‧‧汽缸體 13‧‧‧ cylinder block

14‧‧‧汽缸頭 14‧‧‧ Cylinder head

15‧‧‧活塞 15‧‧‧Piston

16‧‧‧連桿 16‧‧‧ connecting rod

17‧‧‧燃燒室 17‧‧‧combustion chamber

18‧‧‧火星塞 18‧‧‧ Mars Plug

19‧‧‧頭蓋 19‧‧‧ head cover

21‧‧‧進氣埠 21‧‧‧air inlet

22‧‧‧排氣埠 22‧‧‧ exhaust port

23‧‧‧排氣閥 23‧‧‧ exhaust valve

24‧‧‧進氣閥 24‧‧‧Air inlet valve

25‧‧‧閥動機構 25‧‧‧Valve action mechanism

26‧‧‧凸輪軸 26‧‧‧camshaft

27‧‧‧第1軸承 27‧‧‧The first bearing

28‧‧‧第2軸承 28‧‧‧ 2nd bearing

29‧‧‧凸輪鏈條 29‧‧‧ cam chain

31‧‧‧第1鏈輪 31‧‧‧1st sprocket

32‧‧‧第2鏈輪 32‧‧‧Second sprocket

33‧‧‧排氣搖動軸 33‧‧‧Exhaust rocker shaft

34‧‧‧排氣搖動臂 34‧‧‧Exhaust rocker arm

35‧‧‧進氣搖動軸 35‧‧‧Inlet rocker shaft

36‧‧‧進氣搖動臂 36‧‧‧Inlet rocker arm

40‧‧‧減壓機構 40‧‧‧ Decompression mechanism

41‧‧‧凸緣 41‧‧‧ flange

42‧‧‧配重體 42‧‧‧ weight

42a‧‧‧第1卡止部 42a‧‧‧1st locking part

42b‧‧‧第2卡止部 42b‧‧‧ 2nd locking part

43‧‧‧減壓凸輪 43‧‧‧ Decompression cam

44‧‧‧減壓銷 44‧‧‧ Decompression Pin

45‧‧‧回復彈簧 45‧‧‧Restoration spring

46‧‧‧樞銷 46‧‧‧ pivot pin

47‧‧‧第1配重體部 47‧‧‧ 1st weight body

48‧‧‧第2配重體部 48‧‧‧Second weight body

141‧‧‧第1支持壁 141‧‧‧The first support wall

142‧‧‧第2支持壁 142‧‧‧ 2nd support wall

143‧‧‧第1軸承支持孔 143‧‧‧The first bearing support hole

144‧‧‧第1凹部 144‧‧‧1st recess

145‧‧‧第2凹部 145‧‧‧2nd recess

146‧‧‧第3凹部 146‧‧‧3rd recess

231‧‧‧排氣閥彈簧 231‧‧‧Exhaust valve spring

232‧‧‧桿端 232‧‧‧ Rod End

241‧‧‧進氣閥彈簧 241‧‧‧Intake valve spring

242‧‧‧桿端 242‧‧‧ Rod End

261‧‧‧第1凸輪軸端部 261‧‧‧The first camshaft end

262‧‧‧第2凸輪軸端部 262‧‧‧ 2nd camshaft end

263‧‧‧進氣凸輪 263‧‧‧Air intake cam

264‧‧‧排氣凸輪 264‧‧‧Exhaust Cam

265‧‧‧凹部 265‧‧‧Concave

266‧‧‧基圓 266‧‧‧base circle

267‧‧‧凸輪凸部 267‧‧‧ cam protrusion

271‧‧‧內輪 271‧‧‧Inner wheel

272‧‧‧外輪 272‧‧‧outer

341‧‧‧臂本體 341‧‧‧arm body

342‧‧‧排氣輥 342‧‧‧Exhaust roller

343‧‧‧排氣閥推壓部 343‧‧‧Exhaust valve pushing part

361‧‧‧臂本體 361‧‧‧arm body

362‧‧‧進氣輥 362‧‧‧Air intake roller

363‧‧‧進氣閥推壓部 363‧‧‧Intake valve pushing part

411‧‧‧孔 411‧‧‧hole

412‧‧‧第1凸部 412‧‧‧1st protrusion

413‧‧‧第2凸部 413‧‧‧ 2nd convex part

414‧‧‧孔 414‧‧‧hole

421‧‧‧第1部分 421‧‧‧Part 1

421a‧‧‧內徑部 421a‧‧‧Inner diameter section

421b‧‧‧外徑部 421b‧‧‧outer diameter

422‧‧‧第2部分 422‧‧‧Part 2

423‧‧‧樞銷支持部 423‧‧‧ pivot pin support department

423a‧‧‧收納部 423a‧‧‧Storage

423b‧‧‧凸座部 423b‧‧‧ convex seat

423c‧‧‧孔 423c‧‧‧hole

424‧‧‧第1突出部 424‧‧‧ 1st protrusion

424a‧‧‧較近之部分 424a‧‧‧More recent

424b‧‧‧較遠之部分 424b

425‧‧‧突出部 425‧‧‧ protrusion

426‧‧‧內輪接觸部 426‧‧‧Inner wheel contact

426a‧‧‧第1接觸部 426a‧‧‧1st contact

426b‧‧‧第2接觸部 426b‧‧‧2nd contact

426c‧‧‧第3接觸部 426c‧‧‧3rd contact

427‧‧‧第2突出部 427‧‧‧ 2nd protrusion

428‧‧‧第3部分 428‧‧‧Part 3

429‧‧‧第3突出部 429‧‧‧3rd protrusion

431‧‧‧頭部 431‧‧‧Head

432‧‧‧軸部 432‧‧‧Shaft

433‧‧‧槽部 433‧‧‧Slot

434‧‧‧凸輪部 434‧‧‧Cam

451‧‧‧第1彈簧端部 451‧‧‧1st spring end

452‧‧‧第2彈簧端部 452‧‧‧ 2nd spring end

471‧‧‧端部 471‧‧‧ tip

481‧‧‧端部 481‧‧‧ tip

A1‧‧‧第1區域 A1‧‧‧Area 1

A2‧‧‧第2區域 A2‧‧‧ Zone 2

A3‧‧‧第3區域 A3‧‧‧Region 3

A4‧‧‧第4區域 A4‧‧‧Area 4

C1‧‧‧凸輪軸26之旋轉中心 C1‧‧‧ center of rotation of camshaft 26

C2‧‧‧配重體42之旋轉中心 C2‧‧‧ weight center of rotation 42

G1‧‧‧配重體42之重心 Center of gravity of G1‧‧‧ weight body 42

G2‧‧‧無第1突出部424之情形時之配重體42之重心 G2 ‧‧‧ Center of gravity of weight body 42 without first protrusion 424

X‧‧‧橫軸 X‧‧‧ horizontal axis

x1‧‧‧第1橫方向 x1‧‧‧ 1st horizontal direction

x2‧‧‧第2橫方向 x2‧‧‧ 2nd horizontal direction

Y‧‧‧縱軸 Y‧‧‧Vertical axis

y1‧‧‧第1縱方向 y1‧‧‧1st vertical direction

y2‧‧‧第2縱方向 y2‧‧‧ 2nd vertical direction

圖1係車輛之側視圖。 Figure 1 is a side view of the vehicle.

圖2係引擎之一部分之剖視圖。 Figure 2 is a sectional view of a part of the engine.

圖3係垂直於凸輪軸之平面中之汽缸頭之剖視圖。 Figure 3 is a sectional view of the cylinder head in a plane perpendicular to the camshaft.

圖4係凸輪軸組裝體之放大剖視圖。 Fig. 4 is an enlarged sectional view of a camshaft assembly.

圖5係凸輪軸組裝體之立體圖。 Fig. 5 is a perspective view of a camshaft assembly.

圖6係凸輪軸組裝體之分解圖。 Fig. 6 is an exploded view of a camshaft assembly.

圖7係表示閉合狀態之配重體之圖。 Fig. 7 is a view showing a weight body in a closed state.

圖8係表示打開狀態之配重體之圖。 Fig. 8 is a view showing a weight body in an opened state.

圖9(A)、(B)係排氣凸輪之放大圖。 Figures 9 (A) and (B) are enlarged views of the exhaust cam.

圖10係凸輪軸組裝體之側視圖。 Fig. 10 is a side view of a camshaft assembly.

圖11係表示自凸輪軸線方向觀察之凸輪軸組裝體之圖。 FIG. 11 is a view showing a camshaft assembly viewed from the cam axis direction.

圖12係表示自凸輪軸線方向觀察之配重體之圖。 Fig. 12 is a view showing a weight body viewed from the cam axis direction.

圖13係配重體之立體圖。 Fig. 13 is a perspective view of a weight body.

圖14係自圖10之箭頭XIV之方向觀察之凸輪軸組裝體之側視圖。 FIG. 14 is a side view of the camshaft assembly viewed from the direction of arrow XIV in FIG. 10.

圖15係表示自凸輪軸線方向觀察之凸緣、配重體、及回復彈簧之圖。 FIG. 15 is a view showing a flange, a weight body, and a return spring viewed from the cam axis direction.

圖16係表示將頭蓋拆除後之狀態之汽缸頭之圖。 Fig. 16 is a view showing a cylinder head in a state where a head cover is removed.

圖17係表示第1變化例之配重體之圖。 FIG. 17 is a view showing a weight body according to a first modification.

圖18係表示第2變化例之配重體之圖。 FIG. 18 is a view showing a weight body according to a second modification.

圖19係表示第3變化例之配重體之圖。 FIG. 19 is a view showing a weight body according to a third modification.

圖20係表示第4變化例之配重體之圖。 FIG. 20 is a view showing a weight body according to a fourth modification.

圖21係表示第5變化例之配重體之圖。 FIG. 21 is a view showing a weight body according to a fifth modification.

圖22係表示第6變化例之配重體之圖。 FIG. 22 is a view showing a weight body according to a sixth modification.

以下，參照圖式，對實施形態之車輛1進行說明。圖1係車輛1之側視圖。車輛1係速克達(scooter)型機車。車輛1包含車輛本體2、前 輪3、後輪4、把手5、及座部6。車輛本體2包含平坦腳踏板2a。車輛本體2支持前輪3及後輪4。把手5與座部6安裝於車輛本體2。平坦腳踏板2a配置於座部6之前方且下方。 Hereinafter, the vehicle 1 according to the embodiment will be described with reference to the drawings. FIG. 1 is a side view of the vehicle 1. The vehicle is a Scooter locomotive. Vehicle 1 includes vehicle body 2 and front Wheel 3, rear wheel 4, handle 5, and seat 6. The vehicle body 2 includes a flat footrest 2a. The vehicle body 2 supports front wheels 3 and rear wheels 4. The handle 5 and the seat portion 6 are attached to the vehicle body 2. The flat footrest 2 a is disposed in front of and below the seat portion 6.

車輛1包含實施形態之引擎7。圖2係引擎7之一部分之剖視圖。如圖2所示，引擎7包含曲軸11、曲軸箱12、汽缸體13、汽缸頭14、及頭蓋19。汽缸體13連接於曲軸箱12。汽缸體13可與曲軸箱12為一體，或亦可與曲軸箱12分開。汽缸體13收納活塞15。活塞15經由連桿16連結於曲軸11。曲軸11連接於變速箱8。 The vehicle 1 includes an engine 7 according to the embodiment. Fig. 2 is a sectional view of a part of the engine 7. As shown in FIG. 2, the engine 7 includes a crankshaft 11, a crankcase 12, a cylinder block 13, a cylinder head 14, and a head cover 19. The cylinder block 13 is connected to a crankcase 12. The cylinder block 13 may be integrated with the crankcase 12 or may be separated from the crankcase 12. The cylinder block 13 houses a piston 15. The piston 15 is connected to the crankshaft 11 via a connecting rod 16. The crankshaft 11 is connected to the transmission 8.

汽缸頭14連接於汽缸體13。汽缸頭14包含燃燒室17。於汽缸頭14安裝有火星塞18。火星塞18之前端部面向燃燒室17而配置。頭蓋19安裝於汽缸頭14。 The cylinder head 14 is connected to a cylinder block 13. The cylinder head 14 includes a combustion chamber 17. A spark plug 18 is mounted on the cylinder head 14. The front end of the spark plug 18 is disposed facing the combustion chamber 17. The head cover 19 is attached to the cylinder head 14.

引擎7包含閥動機構25及凸輪軸26。閥動機構25與凸輪軸26收納於汽缸頭14。凸輪軸26藉由與閥動機構25接觸，而驅動閥動機構25。 The engine 7 includes a valve mechanism 25 and a camshaft 26. The valve mechanism 25 and the camshaft 26 are housed in the cylinder head 14. The cam shaft 26 drives the valve mechanism 25 by being in contact with the valve mechanism 25.

凸輪軸26支持於汽缸頭14。汽缸頭14包含第1支持壁141及第2支持壁142。第1支持壁141與第2支持壁142沿凸輪軸26之軸線方向(以下稱為「凸輪軸線方向」)並排配置。第1支持壁141支持凸輪軸26。第1支持壁141經由第1軸承27支持凸輪軸26。第2支持壁142支持凸輪軸26。第2支持壁142經由第2軸承28支持凸輪軸26。第1軸承27與第2軸承28將凸輪軸26可旋轉地支持於汽缸頭14。第1軸承27之外徑大於第2軸承28之外徑。再者，第1支持壁141亦可不經由第1軸承27而支持凸輪軸26。第2支持壁142亦可不經由第2軸承28而支持凸輪軸26。 The camshaft 26 is supported by the cylinder head 14. The cylinder head 14 includes a first support wall 141 and a second support wall 142. The first support wall 141 and the second support wall 142 are arranged side by side in the axial direction of the cam shaft 26 (hereinafter referred to as the "cam axis direction"). The first support wall 141 supports the camshaft 26. The first support wall 141 supports the camshaft 26 via a first bearing 27. The second support wall 142 supports the camshaft 26. The second support wall 142 supports the camshaft 26 via a second bearing 28. The first bearing 27 and the second bearing 28 rotatably support the camshaft 26 to the cylinder head 14. The outer diameter of the first bearing 27 is larger than the outer diameter of the second bearing 28. The first support wall 141 may support the camshaft 26 without passing through the first bearing 27. The second support wall 142 may support the camshaft 26 without passing through the second bearing 28.

凸輪軸26包含第1凸輪軸端部261及第2凸輪軸端部262。第1軸承27配置於在凸輪軸線方向上較第2凸輪軸端部262更靠第1凸輪軸端部261處。第2軸承28配置於在凸輪軸線方向上較第1凸輪軸端部261更靠第2凸輪軸端部262處。 The camshaft 26 includes a first camshaft end portion 261 and a second camshaft end portion 262. The first bearing 27 is disposed closer to the first camshaft end portion 261 than the second camshaft end portion 262 in the cam axis direction. The second bearing 28 is disposed closer to the second camshaft end portion 262 than the first camshaft end portion 261 in the cam axis direction.

於凸輪軸26與曲軸11捲繞有凸輪鏈條29。詳細而言，於凸輪軸26 安裝有第1鏈輪31。第1鏈輪31安裝於第1凸輪軸端部261。於曲軸11安裝有第2鏈輪32。凸輪鏈條29捲繞於第1鏈輪31與第2鏈輪32。 A cam chain 29 is wound around the camshaft 26 and the crankshaft 11. In detail, the camshaft 26 The first sprocket 31 is attached. The first sprocket 31 is attached to the first camshaft end portion 261. A second sprocket 32 is attached to the crankshaft 11. The cam chain 29 is wound around the first sprocket 31 and the second sprocket 32.

曲軸11之旋轉經由凸輪鏈條29傳遞至凸輪軸26，藉此，使凸輪軸26旋轉。凸輪軸26包含進氣凸輪263及排氣凸輪264。進氣凸輪263與排氣凸輪264沿凸輪軸線方向並排配置。藉由凸輪軸26旋轉，而使進氣凸輪263與排氣凸輪264旋轉。進氣凸輪263與排氣凸輪264與閥動機構25接觸，藉由進氣凸輪263與排氣凸輪264旋轉，而驅動閥動機構25。 The rotation of the crankshaft 11 is transmitted to the camshaft 26 via the cam chain 29, whereby the camshaft 26 is rotated. The camshaft 26 includes an intake cam 263 and an exhaust cam 264. The intake cam 263 and the exhaust cam 264 are arranged side by side in the cam axis direction. The camshaft 26 rotates to rotate the intake cam 263 and the exhaust cam 264. The intake cam 263 and the exhaust cam 264 are in contact with the valve mechanism 25, and the intake cam 263 and the exhaust cam 264 rotate to drive the valve mechanism 25.

圖3係垂直於凸輪軸26之平面中之汽缸頭14之剖視圖。如圖3所示，引擎7包含排氣閥23及進氣閥24。汽缸頭14包含與燃燒室17連通之進氣埠21及排氣埠22。排氣閥23與進氣閥24收納於汽缸頭14。進氣閥24使進氣埠21打開及閉合。排氣閥23使排氣埠22打開及閉合。閥動機構25使進氣閥24與排氣閥23打開及閉合。 FIG. 3 is a sectional view of the cylinder head 14 in a plane perpendicular to the camshaft 26. As shown in FIG. 3, the engine 7 includes an exhaust valve 23 and an intake valve 24. The cylinder head 14 includes an intake port 21 and an exhaust port 22 in communication with the combustion chamber 17. The exhaust valve 23 and the intake valve 24 are housed in the cylinder head 14. The intake valve 24 opens and closes the intake port 21. The exhaust valve 23 opens and closes the exhaust port 22. The valve mechanism 25 opens and closes the intake valve 24 and the exhaust valve 23.

於進氣閥24安裝有進氣閥彈簧241。進氣閥彈簧241將進氣閥24向進氣閥24閉合進氣埠21之方向彈壓。於排氣閥23安裝有排氣閥彈簧231。排氣閥彈簧231將排氣閥23向排氣閥23閉合排氣埠22之方向彈壓。 An intake valve spring 241 is attached to the intake valve 24. The intake valve spring 241 urges the intake valve 24 in a direction in which the intake valve 24 closes the intake port 21. An exhaust valve spring 231 is attached to the exhaust valve 23. The exhaust valve spring 231 urges the exhaust valve 23 in a direction in which the exhaust valve 23 closes the exhaust port 22.

閥動機構25包含排氣搖動軸33及排氣搖動臂34。排氣搖動軸33與凸輪軸26平行地配置。排氣搖動軸33支持於汽缸頭14。排氣搖動臂34能夠以排氣搖動軸33為中心搖動地支持於排氣搖動軸33。排氣搖動臂34設置為可使排氣閥23動作。排氣搖動臂34包含臂本體341、排氣輥342、及排氣閥推壓部343。 The valve moving mechanism 25 includes an exhaust rocking shaft 33 and an exhaust rocking arm 34. The exhaust rocking shaft 33 is arranged parallel to the cam shaft 26. The exhaust rocking shaft 33 is supported by the cylinder head 14. The exhaust rocking arm 34 can be supported by the exhaust rocking shaft 33 while swinging about the exhaust rocking shaft 33 as a center. The exhaust rocker arm 34 is provided to operate the exhaust valve 23. The exhaust rocking arm 34 includes an arm body 341, an exhaust roller 342, and an exhaust valve pressing portion 343.

臂本體341可搖動地支持於排氣搖動軸33。臂本體341之一端將排氣輥342可旋轉地支持。臂本體341之另一端支持排氣閥推壓部343。排氣輥342與排氣凸輪264接觸，且藉由排氣凸輪264之旋轉而旋轉。排氣閥推壓部343之前端與排氣閥23之桿端232相對向。 The arm body 341 is swingably supported by the exhaust swing shaft 33. One end of the arm body 341 rotatably supports the exhaust roller 342. The other end of the arm body 341 supports an exhaust valve pressing portion 343. The exhaust roller 342 is in contact with the exhaust cam 264 and is rotated by the rotation of the exhaust cam 264. The front end of the exhaust valve pressing portion 343 faces the rod end 232 of the exhaust valve 23.

若藉由排氣凸輪264上推排氣輥342，則排氣搖動臂34搖動，藉此，排氣閥推壓部343下壓排氣閥23之桿端232。藉此，下壓排氣閥23而打開排氣埠22。當不藉由排氣凸輪264上推排氣輥342時，藉由排氣閥彈簧231上推排氣閥23，而閉合排氣埠22。 When the exhaust roller 342 is pushed up by the exhaust cam 264, the exhaust rocking arm 34 is rocked, whereby the exhaust valve pressing portion 343 presses the rod end 232 of the exhaust valve 23. Thereby, the exhaust valve 23 is depressed and the exhaust port 22 is opened. When the exhaust roller 342 is not pushed up by the exhaust cam 264, the exhaust valve 23 is pushed up by the exhaust valve spring 231 to close the exhaust port 22.

閥動機構25包含進氣搖動軸35及進氣搖動臂36。進氣搖動軸35與凸輪軸26平行而配置。進氣搖動軸35支持於汽缸頭14。進氣搖動臂36能夠以進氣搖動軸35為中心搖動地支持於進氣搖動軸35。進氣搖動臂36設置為可使進氣閥24動作。進氣搖動臂36包含臂本體361、進氣輥362、及進氣閥推壓部363。 The valve moving mechanism 25 includes an intake rocking shaft 35 and an intake rocking arm 36. The intake rocking shaft 35 is arranged parallel to the cam shaft 26. The intake rocking shaft 35 is supported by the cylinder head 14. The intake rocker arm 36 is swingably supported by the intake rocker shaft 35 around the intake rocker shaft 35. The intake rocker arm 36 is provided to operate the intake valve 24. The intake rocker arm 36 includes an arm body 361, an intake roller 362, and an intake valve pressing portion 363.

臂本體361可搖動地支持於進氣搖動軸35。臂本體361之一端將進氣輥362可旋轉地支持。臂本體361之另一端支持進氣閥推壓部363。進氣輥362與進氣凸輪263接觸，且藉由進氣凸輪263之旋轉而旋轉。進氣閥推壓部363之前端與進氣閥24之桿端242相對向。 The arm body 361 is swingably supported by the intake swing shaft 35. One end of the arm body 361 rotatably supports the air intake roller 362. The other end of the arm body 361 supports an intake valve pressing portion 363. The intake roller 362 is in contact with the intake cam 263 and is rotated by the rotation of the intake cam 263. The front end of the intake valve pressing portion 363 faces the rod end 242 of the intake valve 24.

若進氣凸輪263上推進氣輥362，則進氣搖動臂36搖動，藉此，進氣閥推壓部363下壓進氣閥24之桿端。藉此，下壓進氣閥24而打開進氣埠21。當不藉由進氣凸輪263上推進氣輥362時，藉由進氣閥彈簧241上推進氣閥24，而閉合進氣埠21。 When the air roller 362 is pushed on the intake cam 263, the intake rocker arm 36 is swung, whereby the intake valve pressing portion 363 pushes down the rod end of the intake valve 24. Thereby, the intake valve 24 is depressed and the intake port 21 is opened. When the air roller 362 is not pushed on the intake cam 263, the air valve 24 is pushed on the intake valve spring 241 to close the intake port 21.

如圖2所示，引擎7包含減壓機構40。圖4係凸輪軸26、減壓機構40、及第1軸承27之組裝體(以下稱為「凸輪軸組裝體」)之放大圖。減壓機構40於凸輪軸線方向上配置於第1凸輪軸端部261與第2凸輪軸端部262之間。減壓機構40配置於汽缸頭14之第1支持壁141與第2支持壁142之間。 As shown in FIG. 2, the engine 7 includes a decompression mechanism 40. FIG. 4 is an enlarged view of an assembly of the camshaft 26, the pressure reducing mechanism 40, and the first bearing 27 (hereinafter referred to as "camshaft assembly"). The decompression mechanism 40 is arranged between the first camshaft end portion 261 and the second camshaft end portion 262 in the cam axis direction. The pressure reducing mechanism 40 is disposed between the first support wall 141 and the second support wall 142 of the cylinder head 14.

圖5係凸輪軸組裝體之立體圖。圖6係凸輪軸組裝體之分解圖。如圖5及圖6所示，減壓機構40包含凸緣41、配重體42、減壓凸輪43、減壓銷44、及回復彈簧45。 Fig. 5 is a perspective view of a camshaft assembly. Fig. 6 is an exploded view of a camshaft assembly. As shown in FIGS. 5 and 6, the pressure reducing mechanism 40 includes a flange 41, a weight body 42, a pressure reducing cam 43, a pressure reducing pin 44, and a return spring 45.

如圖6所示，凸緣41與凸輪軸26分開，且固定於凸輪軸26。詳細 而言，凸緣41包含孔411。於凸緣41之孔411***有凸輪軸26，凸緣41藉由壓入而固定於凸輪軸26。凸緣41於凸輪軸線方向上，配置於配重體42與排氣凸輪264之間。 As shown in FIG. 6, the flange 41 is separated from the cam shaft 26 and is fixed to the cam shaft 26. detailed In other words, the flange 41 includes a hole 411. A camshaft 26 is inserted into a hole 411 of the flange 41, and the flange 41 is fixed to the camshaft 26 by press-fitting. The flange 41 is arranged between the weight body 42 and the exhaust cam 264 in the cam axis direction.

凸緣41包含第1凸部412及第2凸部413。於第1凸部412安裝有樞銷46。於第2凸部413設置有孔414。於第2凸部413之孔414***有減壓凸輪43。 The flange 41 includes a first convex portion 412 and a second convex portion 413. A pivot pin 46 is attached to the first convex portion 412. A hole 414 is provided in the second convex portion 413. A pressure reducing cam 43 is inserted into the hole 414 of the second convex portion 413.

配重體42於凸輪軸線方向上，配置於第1軸承27與凸緣41之間。配重體42相對於凸輪軸26可於閉合狀態與打開狀態之間旋轉地受到支持。 The weight body 42 is arranged between the first bearing 27 and the flange 41 in the cam axis direction. The weight body 42 is rotatably supported with respect to the cam shaft 26 between a closed state and an open state.

圖7及圖8係圖4中之A-A剖視圖。圖7係表示閉合狀態之配重體42。圖8係表示打開狀態之配重體42。 7 and 8 are cross-sectional views taken along A-A in FIG. 4. FIG. 7 shows the weight body 42 in a closed state. FIG. 8 shows the weight body 42 in an opened state.

減壓凸輪43可旋轉地支持於凸緣41。詳細而言，配重體42經由樞銷46可旋轉地支持於凸緣41。配重體42藉由以樞銷46為中心旋轉，而切換成閉合狀態與打開狀態。 The decompression cam 43 is rotatably supported by the flange 41. Specifically, the weight body 42 is rotatably supported by the flange 41 via a pivot pin 46. The weight body 42 is switched to a closed state and an open state by rotating around the pivot pin 46 as a center.

減壓凸輪43經由減壓銷44與配重體42連接。藉此，減壓凸輪43隨著配重體42之旋轉而旋轉。 The decompression cam 43 is connected to the weight body 42 via a decompression pin 44. Thereby, the decompression cam 43 rotates with the rotation of the weight body 42.

詳細而言，如圖4及圖6所示，減壓凸輪43包含頭部431及軸部432。軸部432***至凸緣41之孔414。頭部431配置於凸緣41與配重體42之間。頭部431之外徑大於凸緣41之孔414之內徑。頭部431包含槽部433。槽部433具有自頭部431之端面凹陷之形狀。槽部433自頭部431之外周面朝頭部431之內側延伸。減壓銷44之端部配置於槽部433內。再者，於本實施形態中，內側係指徑向上之內側。又，外側係指徑向上之外側。 Specifically, as shown in FIGS. 4 and 6, the decompression cam 43 includes a head portion 431 and a shaft portion 432. The shaft portion 432 is inserted into the hole 414 of the flange 41. The head portion 431 is disposed between the flange 41 and the weight body 42. The outer diameter of the head 431 is larger than the inner diameter of the hole 414 of the flange 41. The head portion 431 includes a groove portion 433. The groove portion 433 has a shape recessed from an end surface of the head portion 431. The groove portion 433 extends from the outer peripheral surface of the head portion 431 toward the inside of the head portion 431. An end portion of the pressure reducing pin 44 is disposed in the groove portion 433. In addition, in this embodiment, the inner side means the inner side in the radial direction. The outer side means the outer side in the radial direction.

軸部432包含凸輪部434。排氣凸輪264包含凹部265。凹部265具有自排氣凸輪264之外周面朝排氣凸輪264之內側凹陷之形狀。圖9係排氣凸輪264之放大圖。圖10係凸輪軸組裝體之側視圖。 The shaft portion 432 includes a cam portion 434. The exhaust cam 264 includes a recessed portion 265. The recessed portion 265 has a shape that is recessed from the outer peripheral surface of the exhaust cam 264 toward the inside of the exhaust cam 264. FIG. 9 is an enlarged view of the exhaust cam 264. Fig. 10 is a side view of a camshaft assembly.

凸輪部434配置於排氣凸輪264之凹部265內。凸輪部434之截面具有一部分切缺之圓形之形狀。如上所述，減壓凸輪43隨著配重體42之旋轉而旋轉。圖9(A)係表示配重體42打開狀態時之減壓凸輪43。圖9(B)係表示配重體42閉合狀態時之減壓凸輪43。減壓凸輪43隨著配重體42之旋轉，切換成與閥動機構25之排氣輥342之接觸之狀態、及不與排氣輥342接觸之狀態。 The cam portion 434 is disposed in the recessed portion 265 of the exhaust cam 264. The cross section of the cam portion 434 has a circular shape partially cut away. As described above, the decompression cam 43 rotates as the weight body 42 rotates. FIG. 9 (A) shows the decompression cam 43 when the weight body 42 is opened. FIG. 9 (B) shows the decompression cam 43 when the weight body 42 is closed. The decompression cam 43 is switched to a state in which it is in contact with the exhaust roller 342 of the valve operating mechanism 25 and a state in which it is not in contact with the exhaust roller 342 as the weight body 42 rotates.

詳細而言，當配重體42為打開狀態時，如圖9(A)所示，減壓凸輪43之凸輪部434之整體配置於凹部265內。即，當配重體42為打開狀態時，凸輪部434成為不自排氣凸輪264之外周面朝外側突出之狀態。藉此，當配重體42為打開狀態時，減壓凸輪43不與排氣輥342接觸。 Specifically, when the weight body 42 is in an open state, as shown in FIG. 9A, the entire cam portion 434 of the decompression cam 43 is disposed in the recessed portion 265. That is, when the weight body 42 is in the open state, the cam portion 434 does not protrude outward from the outer peripheral surface of the exhaust cam 264. Thereby, when the weight body 42 is in the open state, the decompression cam 43 does not contact the exhaust roller 342.

當配重體42為閉合狀態時，如圖9(B)所示，減壓凸輪43之凸輪部434之一部分配置於凹部265外。即，當配重體42為閉合狀態時，凸輪部434之一部分成為自排氣凸輪264之外周面朝外側突出之狀態。藉此，當配重體42為閉合狀態時，減壓凸輪43與排氣輥342接觸。 When the weight body 42 is in a closed state, as shown in FIG. 9 (B), a part of the cam portion 434 of the decompression cam 43 is disposed outside the concave portion 265. That is, when the weight body 42 is in the closed state, a part of the cam portion 434 is in a state of protruding outward from the outer peripheral surface of the exhaust cam 264. Thereby, when the weight body 42 is in a closed state, the decompression cam 43 comes into contact with the exhaust roller 342.

回復彈簧45以使配重體42自打開狀態恢復至閉合狀態之方式對該配重體42彈壓。於本實施形態中，回復彈簧45係螺旋彈簧。但是，回復彈簧45亦可為其他種類之彈簧。如圖6所示，回復彈簧45包含第1彈簧端部451及第2彈簧端部452。第1彈簧端部451沿凸輪軸線方向延伸。第2彈簧端部452沿與凸輪軸線方向交叉之方向延伸。第2彈簧端部452沿回復彈簧45之周向延伸。第1彈簧端部451卡止於凸緣41。第2彈簧端部452卡止於配重體42。 The return spring 45 urges the weight body 42 so that the weight body 42 returns from the open state to the closed state. In this embodiment, the return spring 45 is a coil spring. However, the return spring 45 may be another type of spring. As shown in FIG. 6, the return spring 45 includes a first spring end portion 451 and a second spring end portion 452. The first spring end portion 451 extends in the cam axis direction. The second spring end portion 452 extends in a direction crossing the cam axis direction. The second spring end portion 452 extends in the circumferential direction of the return spring 45. The first spring end portion 451 is locked to the flange 41. The second spring end portion 452 is locked to the weight body 42.

繼而，對配重體42之構造進行詳細說明。如圖7所示，自凸輪軸線方向觀察，將通過凸輪軸26之旋轉中心C1與配重體42之旋轉中心C2之直線設為縱軸Y。將與縱軸Y正交、且通過凸輪軸26之旋轉中心C1之直線設為橫軸X。將平行於縱軸Y之方向中之自凸輪軸26之旋轉中心C1朝向配重體42之旋轉中心C2之方向設為第1縱方向y1。將與第 1縱方向y1相反之方向設為第2縱方向y2。將平行於橫軸X之方向中之一者設為第1橫方向x1。將與第1橫方向x1相反之方向設為第2橫方向x2。 Next, the structure of the weight body 42 will be described in detail. As shown in FIG. 7, when viewed from the cam axis direction, a straight line passing through the rotation center C1 of the cam shaft 26 and the rotation center C2 of the weight body 42 is taken as the vertical axis Y. A straight line orthogonal to the vertical axis Y and passing through the rotation center C1 of the cam shaft 26 is referred to as a horizontal axis X. In the direction parallel to the longitudinal axis Y, the direction from the rotation center C1 of the cam shaft 26 toward the rotation center C2 of the weight body 42 is set to the first longitudinal direction y1. Will be with The direction opposite to the one vertical direction y1 is the second vertical direction y2. One of the directions parallel to the horizontal axis X is set to the first horizontal direction x1. A direction opposite to the first lateral direction x1 is referred to as a second lateral direction x2.

又，將相對於橫軸X位於第1縱方向y1、並且相對於縱軸Y位於第1橫方向x1之區域設為第1區域A1。將相對於橫軸X位於第2縱方向y2、並且相對於縱軸Y位於第1橫方向x1之區域設為第2區域A2。自凸輪軸線方向觀察，將相對於橫軸X位於第2縱方向y2、並且相對於縱軸Y位於第2橫方向x2之區域設為第3區域A3。將相對於橫軸X位於第1縱方向y1、並且相對於縱軸Y位於第2橫方向x2之區域設為第4區域A4。 A region located in the first vertical direction y1 with respect to the horizontal axis X and in the first horizontal direction x1 with respect to the vertical axis Y is referred to as a first region A1. A region located in the second vertical direction y2 with respect to the horizontal axis X and in the first horizontal direction x1 with respect to the vertical axis Y is referred to as a second region A2. When viewed from the cam axis direction, a region located in the second vertical direction y2 with respect to the horizontal axis X and in the second horizontal direction x2 with respect to the vertical axis Y is referred to as a third region A3. A region located in the first vertical direction y1 with respect to the horizontal axis X and in a second horizontal direction x2 with respect to the vertical axis Y is referred to as a fourth region A4.

再者，圖7係表示於凸輪軸線方向上自第1凸輪軸端部261側觀察之配重體42。因此，上述方向x1、x2、y1、y2及區域A1~A4係於在凸輪軸線方向上自第1凸輪軸端部261側觀察之情形時所定義，但亦可於在凸輪軸線方向上自第2凸輪軸端部262側觀察之情形時定義上述方向x1、x2、y1、y2及區域A1~A4。 In addition, FIG. 7 shows the weight body 42 viewed from the first camshaft end portion 261 side in the cam axis direction. Therefore, the above directions x1, x2, y1, y2, and areas A1 to A4 are defined when the cam axis direction is viewed from the first camshaft end portion 261 side, but may be defined from the 2 When the camshaft end 262 is viewed from the side, the directions x1, x2, y1, y2, and areas A1 to A4 are defined.

如圖7所示，配重體42具有沿凸輪軸26之周向延伸之形狀。配重體42於第1區域A1、第2區域A2、及第4區域A4配置於凸輪軸26之周圍。配重體42具有於凸輪軸26之周向上跨及第1~第4區域A1~A4中之複數個區域之形狀。自凸輪軸線方向觀察，配重體42並不具有配置於第3區域A3之部分。 As shown in FIG. 7, the weight body 42 has a shape extending in the circumferential direction of the cam shaft 26. The weight body 42 is arranged around the cam shaft 26 in the first area A1, the second area A2, and the fourth area A4. The weight body 42 has a shape that spans in the circumferential direction of the cam shaft 26 and a plurality of areas in the first to fourth areas A1 to A4. When viewed from the cam axis direction, the weight body 42 does not have a portion arranged in the third area A3.

詳細而言，配重體42包含第1配重體部47及第2配重體部48。第1配重體部47自配重體42之旋轉中心C2沿凸輪軸26之周向且第1橫方向x1延伸。第1配重體部47之周向上之端部471相對於縱軸Y位於第1橫方向x1。即，第1配重體部47之整體相對於縱軸Y位於第1橫方向x1。自凸輪軸線方向觀察，第1配重體部47之端部471配置於第2區域A2。 Specifically, the weight body 42 includes a first weight body portion 47 and a second weight body portion 48. The first weight body portion 47 extends from the rotation center C2 of the weight body 42 in the circumferential direction of the cam shaft 26 and in the first lateral direction x1. An end portion 471 in the circumferential direction of the first weight body portion 47 is located in the first lateral direction x1 with respect to the longitudinal axis Y. That is, the entire first weight body portion 47 is located in the first horizontal direction x1 with respect to the vertical axis Y. When viewed from the cam axis direction, the end portion 471 of the first weight body portion 47 is disposed in the second area A2.

第2配重體部48自配重體42之旋轉中心C2沿凸輪軸26之周向且第 2橫方向x2延伸。第2配重體部48之周向上之端部481相對於縱軸Y位於第2橫方向x2。即，第2配重體部48之整體相對於縱軸Y位於第2橫方向x2。自凸輪軸線方向觀察，第2配重體部48之端部481配置於第4區域A4。 The second weight body portion 48 extends from the center of rotation C2 of the weight body 42 in the circumferential direction of the cam shaft 26 and 2 horizontal direction x2 extends. An end portion 481 in the circumferential direction of the second weight body portion 48 is located in the second lateral direction x2 with respect to the longitudinal axis Y. That is, the entire second weight body portion 48 is located in the second horizontal direction x2 with respect to the vertical axis Y. When viewed from the cam axis direction, the end portion 481 of the second weight body portion 48 is disposed in the fourth area A4.

於凸輪軸26之周向上，第1配重體部47較第2配重體部48長。即，繞凸輪軸26之旋轉中心C1之配重體42之旋轉中心C2至第1配重體部47之端部471之角度大於配重體42之旋轉中心C2至第2配重體部48之端部481之角度。 In the circumferential direction of the cam shaft 26, the first weight body portion 47 is longer than the second weight body portion 48. That is, the angle of the rotation center C2 of the weight body 42 around the rotation center C1 of the cam shaft 26 to the end portion 471 of the first weight body portion 47 is larger than the rotation center C2 to the second weight body portion 48 of the weight body 42 Angle of the end 481.

第1配重體部47包含第1部分421及第2部分422。自凸輪軸線方向觀察，第1部分421配置於第1區域A1。自凸輪軸線方向觀察，第2部分422配置於第2區域A2。第2配重體部48配置於第4區域A4。 The first weight body 47 includes a first portion 421 and a second portion 422. When viewed from the cam axis direction, the first portion 421 is disposed in the first region A1. When viewed from the cam axis direction, the second portion 422 is disposed in the second area A2. The second weight body 48 is arranged in the fourth area A4.

配重體42包含樞銷支持部423。樞銷支持部423跨第1部分421與第2部分422而配置。樞銷46安裝於樞銷支持部423。 The weight body 42 includes a pivot pin support portion 423. The pivot pin support portion 423 is disposed across the first portion 421 and the second portion 422. The pivot pin 46 is attached to the pivot pin support portion 423.

排氣凸輪264包含朝較基圓266更靠外側突出之凸輪凸部267(cam lobe)。自凸輪軸線方向觀察，樞銷46之一部分並不與凸輪凸部267重疊。即，自凸輪軸線方向觀察，樞銷46之一部分位於較排氣凸輪264之外周面更靠外側處。又，樞銷46包含自凸輪軸線方向觀察位於較基圓266更靠內側之部分。 The exhaust cam 264 includes a cam lobe 267 protruding toward the outside from the base circle 266. As viewed from the cam axis direction, a part of the pivot pin 46 does not overlap the cam projection 267. That is, when viewed from the cam axis direction, a part of the pivot pin 46 is located further outside than the outer peripheral surface of the exhaust cam 264. In addition, the pivot pin 46 includes a portion located further inside than the base circle 266 as viewed from the cam axis direction.

減壓銷44連接於第1配重體部47。詳細而言，減壓銷44連接於第2部分422。自凸輪軸線方向觀察，減壓銷44配置於第2區域A2。自凸輪軸線方向觀察，配重體42之旋轉中心C2與減壓銷44之間之距離為配重體42之旋轉中心C2與凸輪軸26之旋轉中心C1之間之距離以上。 The pressure reduction pin 44 is connected to the first weight body 47. Specifically, the pressure reducing pin 44 is connected to the second portion 422. When viewed from the cam axis direction, the decompression pin 44 is arranged in the second area A2. Viewed from the cam axis direction, the distance between the rotation center C2 of the weight body 42 and the pressure reduction pin 44 is greater than the distance between the rotation center C2 of the weight body 42 and the rotation center C1 of the cam shaft 26.

圖11係表示自凸輪軸線方向觀察之凸輪軸組裝體之圖。如圖11所示，自凸輪軸線方向觀察，凸緣41之外形包含大於第1軸承27之外形之部分。詳細而言，第1凸部412朝較第1軸承27之外周面更靠外側突出。 FIG. 11 is a view showing a camshaft assembly viewed from the cam axis direction. As shown in FIG. 11, when viewed from the cam axis direction, the outer shape of the flange 41 includes a portion larger than the outer shape of the first bearing 27. Specifically, the first convex portion 412 protrudes further outward than the outer peripheral surface of the first bearing 27.

於閉合狀態下，配重體42之第1部分421包含第1突出部424。自凸輪軸線方向觀察，第1突出部424較第1軸承27之外周面更朝外側突出。自凸輪軸線方向觀察，第2部分422之外周面位於較第1軸承27之外周面更靠內側處。自凸輪軸線方向觀察，第2配重體部48之外周面位於較第1軸承27之外周面更靠內側處。 In the closed state, the first portion 421 of the weight body 42 includes a first protruding portion 424. When viewed from the cam axis direction, the first protruding portion 424 projects further outward than the outer peripheral surface of the first bearing 27. When viewed from the cam axis direction, the outer peripheral surface of the second portion 422 is located more inward than the outer peripheral surface of the first bearing 27. When viewed from the cam axis direction, the outer peripheral surface of the second weight body portion 48 is located more inward than the outer peripheral surface of the first bearing 27.

樞銷支持部423包含突出部425，自凸輪軸線方向觀察，該突出部425朝較第1軸承27之外周面更靠外側突出。突出部425之突出長度之最大值大於第1突出部424之突出長度之最大值。即，突出部425較第1突出部424更大幅地朝第1軸承27之徑向突出。再者，突出長度係指於第1軸承27之徑向上自第1軸承27之外周面之突出長度。 The pivot pin support portion 423 includes a protruding portion 425, and the protruding portion 425 projects further outward than the outer peripheral surface of the first bearing 27 when viewed from the cam axis direction. The maximum value of the protruding length of the protruding portion 425 is larger than the maximum value of the protruding length of the first protruding portion 424. That is, the protruding portion 425 protrudes more radially than the first protruding portion 424 in the radial direction of the first bearing 27. The protruding length refers to a protruding length of the first bearing 27 in the radial direction from the outer peripheral surface of the first bearing 27.

如圖11所示，第1軸承27包含內輪271及外輪272。內輪271接觸於凸輪軸26。外輪272接觸於汽缸頭14之第1支持壁141。如圖7所示，配重體42包含內輪接觸部426。內輪接觸部426於凸輪軸線方向上與內輪271並排配置。內輪接觸部426自鄰接於第1軸承27之配重體42之表面朝內輪271突出。 As shown in FIG. 11, the first bearing 27 includes an inner wheel 271 and an outer wheel 272. The inner wheel 271 is in contact with the camshaft 26. The outer wheel 272 is in contact with the first support wall 141 of the cylinder head 14. As shown in FIG. 7, the weight body 42 includes an inner wheel contact portion 426. The inner wheel contact portion 426 is arranged side by side with the inner wheel 271 in the cam axis direction. The inner wheel contact portion 426 projects from the surface of the weight body 42 adjacent to the first bearing 27 toward the inner wheel 271.

如圖11所示，內輪接觸部426位於較外輪272之內周面更靠內側處。再者，無論配重體42處於閉合狀態及打開狀態中之何種狀態，內輪接觸部426均位於較外輪272之內周面更靠內側處。自凸輪軸線方向觀察，內輪接觸部426之至少一部分配置於較凸輪軸26之旋轉中心C1更靠近配重體42之旋轉中心C2。自凸輪軸線方向觀察，內輪接觸部426位於配重體42之旋轉中心C2與凸輪軸26之間。如圖4所示，於內輪接觸部426接觸於內輪271之狀態下，配重體42之其他部分並不接觸於外輪272。 As shown in FIG. 11, the inner wheel contact portion 426 is located more inward than the inner peripheral surface of the outer wheel 272. Moreover, the inner wheel contact portion 426 is located more inward than the inner peripheral surface of the outer wheel 272 regardless of the state of the weight body 42 in the closed state and the opened state. Viewed from the cam axis direction, at least a part of the inner wheel contact portion 426 is disposed closer to the rotation center C2 of the weight body 42 than the rotation center C1 of the cam shaft 26. Viewed from the cam axis direction, the inner wheel contact portion 426 is located between the rotation center C2 of the weight body 42 and the cam shaft 26. As shown in FIG. 4, in a state where the inner wheel contact portion 426 is in contact with the inner wheel 271, other parts of the weight body 42 are not in contact with the outer wheel 272.

詳細而言，當配重體42為閉合狀態，內輪接觸部426跨及第4區域A4、第1區域A1、及第2區域A2而配置。內輪接觸部426包含第1接觸部426a、第2接觸部426b、及第3接觸部426c。當配重體42為閉合狀 態，第1接觸部426a配置於第1區域A1。當配重體42為閉合狀態，第2接觸部426b配置於第2區域A2。當配重體42為閉合狀態，第3接觸部426c配置於第4區域A4。自凸輪軸線方向觀察，第1接觸部426a之面積大於第2接觸部426b之面積。自凸輪軸線方向觀察，第1接觸部426a之面積大於第3接觸部426c之面積。 Specifically, when the weight body 42 is in a closed state, the inner wheel contact portion 426 is disposed across the fourth area A4, the first area A1, and the second area A2. The inner-wheel contact portion 426 includes a first contact portion 426a, a second contact portion 426b, and a third contact portion 426c. When the weight 42 is closed In this state, the first contact portion 426a is disposed in the first region A1. When the weight body 42 is in a closed state, the second contact portion 426b is disposed in the second area A2. When the weight body 42 is closed, the third contact portion 426c is disposed in the fourth area A4. When viewed from the cam axis direction, the area of the first contact portion 426a is larger than the area of the second contact portion 426b. When viewed from the cam axis direction, the area of the first contact portion 426a is larger than the area of the third contact portion 426c.

圖12中之G1係表示配重體42之重心之位置。G2係表示無第1突出部424之情形時之配重體42之重心之位置。再者，於圖12中，對第1突出部424標註有影線。「無第1突出部424之情形時」係指將於圖12中標註有影線之部分去除之後之狀態。又，於圖12中，以二點鏈線表示第1軸承27之外周面。如圖12所示，自凸輪軸線方向觀察，配重體42之重心G1配置於第1區域A1。配重體42之重心G1與凸輪軸26之旋轉中心C1之間之距離大於配重體42之重心G1與配重體42之旋轉中心C2之間之距離。自凸輪軸線方向觀察，第1突出部424包含：較近之部分424a，其於第1軸承27之周向上，較無第1突出部424時之配重體42之重心G2之位置更靠近配重體42之旋轉中心C2；及較遠之部分424b，其於第1軸承27之周向上，較無第1突出部424時之配重體42之重心G2之位置更遠離配重體42之旋轉中心C2。關於自第1軸承27之外周面朝外側之突出量，較近之部分424a大於較遠之部分424b。 G1 in FIG. 12 indicates the position of the center of gravity of the weight body 42. G2 indicates the position of the center of gravity of the weight body 42 when there is no first protruding portion 424. Note that in FIG. 12, the first protruding portion 424 is hatched. “When there is no first protruding portion 424” refers to a state after the portion marked with a hatched line in FIG. 12 is removed. In FIG. 12, the outer peripheral surface of the first bearing 27 is shown by a two-dot chain line. As shown in FIG. 12, when viewed from the cam axis direction, the center of gravity G1 of the weight body 42 is disposed in the first area A1. The distance between the center of gravity G1 of the weight body 42 and the center of rotation C1 of the cam shaft 26 is greater than the distance between the center of gravity G1 of the weight body 42 and the center of rotation C2 of the weight body 42. Viewed from the cam axis direction, the first protrusion 424 includes: a closer portion 424a, which is closer to the weight in the circumferential direction of the first bearing 27 than the center of gravity G2 of the weight body 42 without the first protrusion 424 The center of rotation C2 of the weight 42; and the farther portion 424b, which is farther away from the position of the center of gravity G2 of the weight body 42 than the weight body 42 when there is no first protrusion 424 in the circumferential direction of the first bearing 27 Rotation center C2. As for the amount of protrusion from the outer peripheral surface of the first bearing 27 to the outside, the closer portion 424a is larger than the farther portion 424b.

又，自凸輪軸線方向觀察，於內輪接觸部426中較配重體42之重心G1更靠近配重體42之旋轉中心C2的部分大於在內輪接觸部426中較配重體42之重心G1更遠離配重體42之旋轉中心C2的部分。例如，凸輪軸26之徑向上之第1接觸部426a之最大寬度大於凸輪軸26之徑向上之第2接觸部426b之最大寬度。 Also, as viewed from the direction of the cam axis, the portion of the inner wheel contact portion 426 that is closer to the center of rotation C2 of the weight body 42 than the center of gravity 42 of the weight body 42 is larger than the center of gravity of the weight body 42 in the inner wheel contact portion 426 G1 is further away from the center of rotation C2 of the weight body 42. For example, the maximum width of the first contact portion 426 a in the radial direction of the cam shaft 26 is larger than the maximum width of the second contact portion 426 b in the radial direction of the cam shaft 26.

圖13係表示配重體42之第2凸輪軸端部262側之表面之立體圖。圖14係於圖10中自箭頭XIV之方向觀察之凸輪軸組裝體之側視圖。如圖13所示，凸輪軸線方向上之第1部分421之最大厚度大於凸輪軸線方 向上之第2部分422之最大厚度。凸輪軸線方向上之第2配重體部48之最大厚度大於凸輪軸線方向上之第2部分422之最大厚度。 FIG. 13 is a perspective view showing a surface on the second camshaft end portion 262 side of the weight body 42. 14 is a side view of the camshaft assembly viewed from the direction of arrow XIV in FIG. 10. As shown in FIG. 13, the maximum thickness of the first portion 421 in the direction of the cam axis is larger than that of the cam axis. The maximum thickness of the upward part 2 422. The maximum thickness of the second weight body portion 48 in the cam axis direction is larger than the maximum thickness of the second portion 422 in the cam axis direction.

如圖13所示，第1部分421包含內徑部421a及外徑部421b。內徑部421a位於外徑部421b之內側。凸輪軸線方向上之外徑部421b之厚度大於凸輪軸線方向上之內徑部421a之厚度。外徑部421b包含上述第1突出部424。因此，凸輪軸線方向上之第1突出部424之最大厚度大於凸輪軸線方向上之第2部分422之最大厚度。凸輪軸線方向上之第1突出部424之最大厚度大於凸輪軸線方向上之第2配重體部48之最大厚度。凸輪軸線方向上之第1突出部424之厚度大於凸輪軸線方向上之樞銷支持部423之厚度。 As shown in FIG. 13, the first portion 421 includes an inner diameter portion 421 a and an outer diameter portion 421 b. The inner diameter portion 421a is located inside the outer diameter portion 421b. The thickness of the outer diameter portion 421b in the cam axis direction is larger than the thickness of the inner diameter portion 421a in the cam axis direction. The outer diameter portion 421 b includes the first protruding portion 424. Therefore, the maximum thickness of the first protruding portion 424 in the cam axis direction is larger than the maximum thickness of the second portion 422 in the cam axis direction. The maximum thickness of the first protruding portion 424 in the cam axis direction is larger than the maximum thickness of the second weight body portion 48 in the cam axis direction. The thickness of the first protruding portion 424 in the cam axis direction is greater than the thickness of the pivot pin support portion 423 in the cam axis direction.

如圖10所示，自凸輪軸26之徑向觀察，配重體42之一部分與凸緣41重疊。詳細而言，自凸輪軸26之徑向觀察，第1部分421之外徑部421b與凸緣41重疊。第2凸輪軸端部262側之第2配重體部48之表面及內徑部421a之表面與第1凸輪軸端部261側之凸緣41之表面相對向。於第2部分422與凸緣41之間配置有上述減壓凸輪43之頭部431。 As shown in FIG. 10, when viewed from the radial direction of the camshaft 26, a part of the weight body 42 overlaps the flange 41. Specifically, when viewed from the radial direction of the cam shaft 26, the outer diameter portion 421 b of the first portion 421 overlaps the flange 41. The surface of the second weight body portion 48 on the second camshaft end portion 262 side and the surface of the inner diameter portion 421a face the surface of the flange 41 on the first camshaft end portion 261 side. A head 431 of the pressure reducing cam 43 is disposed between the second portion 422 and the flange 41.

如圖13所示，樞銷支持部423包含收納部423a及凸座部423b。凸座部423b自收納部423a朝凸輪軸線方向突出。凸輪軸線方向上之收納部423a之厚度小於凸輪軸線方向上之第1部分421及第2配重體部48之厚度。因此，收納部423a具有自配重體42之表面朝凸輪軸線方向凹陷之形狀。 As shown in FIG. 13, the pivot pin support portion 423 includes a receiving portion 423 a and a convex portion 423 b. The boss portion 423b protrudes from the storage portion 423a in the cam axis direction. The thickness of the accommodating portion 423a in the cam axis direction is smaller than the thickness of the first portion 421 and the second weight body portion 48 in the cam axis direction. Therefore, the storage portion 423a has a shape recessed from the surface of the weight body 42 in the cam axis direction.

圖15係自第2凸輪軸端部262側觀察凸緣41、配重體42、及回復彈簧45之圖。如圖15所示，收納部423a收納回復彈簧45。凸座部423b***至上述回復彈簧45。於凸座部423b設置有孔423c。於凸座部423b之孔423c***有樞銷46。 FIG. 15 is a view of the flange 41, the weight body 42, and the return spring 45 as viewed from the second camshaft end portion 262 side. As shown in FIG. 15, the storage portion 423 a stores the return spring 45. The boss portion 423b is inserted into the return spring 45 described above. A hole 423c is provided in the convex portion 423b. A pivot pin 46 is inserted into the hole 423c of the boss portion 423b.

如圖13及圖15所示，配重體42包含第2卡止部42b。第2卡止部42b卡止於回復彈簧45之第2彈簧端部452。第2卡止部42b包含於第1部 分421。詳細而言，第2卡止部42b係第1部分421中之相對於樞銷支持部423而形成之階部。 As shown in FIGS. 13 and 15, the weight body 42 includes a second locking portion 42 b. The second locking portion 42 b is locked to the second spring end portion 452 of the return spring 45. The second locking portion 42b is included in the first portion Points 421. Specifically, the second locking portion 42 b is a stepped portion formed in the first portion 421 with respect to the pivot pin supporting portion 423.

如圖14及圖15所示，凸緣41包含第1卡止部42a。第1卡止部42a卡止於回復彈簧45之第1彈簧端部451。詳細而言，第1卡止部42a係第1凸部412之一部分。第1卡止部42a一體地成型於凸緣41。例如，凸緣41包含第1卡止部42a，利用燒結、鍛造、或鑄造等製法而一體地成形。 As shown in FIGS. 14 and 15, the flange 41 includes a first locking portion 42 a. The first locking portion 42 a is locked to the first spring end portion 451 of the return spring 45. Specifically, the first locking portion 42 a is a part of the first convex portion 412. The first locking portion 42 a is integrally formed on the flange 41. For example, the flange 41 includes the first locking portion 42 a and is integrally formed by a manufacturing method such as sintering, forging, or casting.

圖16係表示將頭蓋19拆除後之狀態之汽缸頭14之圖。如圖16所示，汽缸頭14包含第1軸承支持孔143。第1軸承支持孔143支持第1軸承27。第1軸承支持孔143設置於第1支持壁141。第1軸承支持孔143包含第1凹部144、第2凹部145、及第3凹部146。第1凹部144、第2凹部145、及第3凹部146位於相對於第1軸承支持孔143之中心與曲軸11為相反的一側。第1凹部144具有可使第1突出部424及進氣凸輪263通過之形狀。第2凹部145具有可使排氣凸輪264通過之形狀。第3凹部146具有可使樞銷支持部423通過之形狀。再者，亦可使第1凹部144之一部分位於相對於第1軸承支持孔143之中心與曲軸11為相反的一側，其他部分位於相對於第1軸承支持孔143之中心與曲軸11為相同的一側。或，亦可使第2凹部145之一部分位於相對於第1軸承支持孔143之中心與曲軸11為相反的一側，其他部分位於相對於第1軸承支持孔143之中心與曲軸11為相同的一側。 FIG. 16 is a diagram showing the cylinder head 14 in a state where the head cover 19 is removed. As shown in FIG. 16, the cylinder head 14 includes a first bearing support hole 143. The first bearing support hole 143 supports the first bearing 27. The first bearing support hole 143 is provided in the first support wall 141. The first bearing support hole 143 includes a first recessed portion 144, a second recessed portion 145, and a third recessed portion 146. The first recessed portion 144, the second recessed portion 145, and the third recessed portion 146 are located on the side opposite to the crankshaft 11 with respect to the center of the first bearing support hole 143. The first recessed portion 144 has a shape through which the first protruding portion 424 and the intake cam 263 can pass. The second concave portion 145 has a shape through which the exhaust cam 264 can pass. The third recessed portion 146 has a shape through which the pivot pin support portion 423 can pass. Furthermore, one part of the first recessed portion 144 may be located on the side opposite to the crankshaft 11 with respect to the center of the first bearing support hole 143, and the other part may be located on the same side as the crankshaft 11 with respect to the center of the first bearing support hole 143 The side. Alternatively, one part of the second recess 145 may be located on the side opposite to the crankshaft 11 relative to the center of the first bearing support hole 143, and the other part may be located on the same side as the crankshaft 11 relative to the center of the first bearing support hole 143 One side.

於本實施形態之引擎7中，配重體42中之位於第1區域A1之第1部分421之第1突出部424朝較第1軸承27之外周面更靠外側突出。藉此，與第1部分421不突出之情形時(參照圖12之重心G2)相比，可使配重體42之重心G1遠離凸輪軸26之旋轉中心C1。因此，若凸輪軸26之旋轉速度相同，則施加至配重體42之離心力變大。藉此，可增大回復彈簧45之彈力，故而無需使設定轉數上升，便可抑制重力所引起之配重體 42之打開。 In the engine 7 of this embodiment, the first protruding portion 424 of the weight body 42 located in the first portion 421 of the first region A1 protrudes further outward than the outer peripheral surface of the first bearing 27. As a result, the center of gravity G1 of the weight body 42 can be separated from the center of rotation C1 of the cam shaft 26 as compared with the case where the first portion 421 does not protrude (see the center of gravity G2 of FIG. 12). Therefore, if the rotation speed of the cam shaft 26 is the same, the centrifugal force applied to the weight body 42 becomes large. With this, the elastic force of the return spring 45 can be increased, so that the weight body caused by gravity can be suppressed without increasing the set number of revolutions. 42 of them open.

自凸輪軸26之軸線方向觀察，配重體42之第2部分422之外周面位於較第1軸承27之外周面更靠內側處。因此，可使配重體42之重心G1進一步遠離凸輪軸26之旋轉中心C1。又，與第2部分422之外周面位於較第1軸承27之外周面更靠外側之情形相比，可使配重體42之重心G1之位置靠近配重體42之旋轉中心C2。藉此，可減小作用至配重體42之重力所引起之力矩。因此，可抑制重力所引起之配重體42之打開。藉此，易於避免當引擎7起動時配重體42打開之狀態，故而可提高引擎7之起動性。 When viewed from the axial direction of the cam shaft 26, the outer peripheral surface of the second portion 422 of the weight body 42 is located more inward than the outer peripheral surface of the first bearing 27. Therefore, the center of gravity G1 of the weight body 42 can be further separated from the rotation center C1 of the cam shaft 26. In addition, compared with the case where the outer peripheral surface of the second portion 422 is located further outside than the outer peripheral surface of the first bearing 27, the center of gravity G1 of the weight body 42 can be brought closer to the center of rotation C2 of the weight body 42. Thereby, the moment caused by the gravity acting on the weight body 42 can be reduced. Therefore, the weight body 42 can be prevented from being opened by gravity. Thereby, it is easy to avoid the state where the weight body 42 is opened when the engine 7 is started, so that the startability of the engine 7 can be improved.

凸輪軸26之軸線方向上之第1突出部424之最大厚度大於凸輪軸26之軸線方向上之第2部分422之最大厚度。因此，可使配重體42之重心G1進一步遠離凸輪軸26之旋轉中心C1。 The maximum thickness of the first protruding portion 424 in the axial direction of the cam shaft 26 is greater than the maximum thickness of the second portion 422 in the axial direction of the cam shaft 26. Therefore, the center of gravity G1 of the weight body 42 can be further separated from the rotation center C1 of the cam shaft 26.

自凸輪軸26之軸線方向觀察，第1突出部424包含：較近之部分424a，其於第1軸承27之周向上，較無第1突出部424時之配重體42之重心G2之位置更靠近配重體42之旋轉中心C2；及較遠之部分424b，其於第1軸承27之周向上，較無第1突出部424時之配重體42之重心G2之位置更遠離配重體42之旋轉中心C2，且較近之部分424a大於較遠之部分424b。因此，與較遠之部分424b大於較近之部分424a之情形相比，可使配重體42之重心G1進一步靠近配重體42之旋轉中心C2。 Viewed from the axial direction of the camshaft 26, the first protruding portion 424 includes: a closer portion 424a, which is located in the circumferential direction of the first bearing 27 and has a position of the center of gravity G2 of the weight body 42 when the first protruding portion 424 is not present The rotation center C2 closer to the weight body 42; and the further portion 424b, which is farther away from the weight in the circumferential direction of the first bearing 27 than the position of the center of gravity G2 of the weight body 42 when there is no first protrusion 424 The center of rotation C2 of the body 42, and the closer portion 424a is larger than the farther portion 424b. Therefore, compared with the case where the farther portion 424b is larger than the closer portion 424a, the center of gravity G1 of the weight body 42 can be brought closer to the rotation center C2 of the weight body 42.

凸輪軸26之軸線方向上之第1突出部424之厚度大於凸輪軸26之軸線方向上之樞銷支持部423之厚度。因此，與第1突出部424之厚度小於樞銷支持部423之厚度之情形相比，可使配重體42之重心G1遠離凸輪軸26之旋轉中心C1。 The thickness of the first protruding portion 424 in the axial direction of the cam shaft 26 is greater than the thickness of the pivot pin support portion 423 in the axial direction of the cam shaft 26. Therefore, compared with the case where the thickness of the first protruding portion 424 is smaller than the thickness of the pivot pin support portion 423, the center of gravity G1 of the weight body 42 can be separated from the rotation center C1 of the cam shaft 26.

於汽缸頭14之第1軸承支持孔143，具有第1凹部144、第2凹部145、及第3凹部146。因此，當將凸輪軸26、減壓機構40、及第1軸承27一體地安裝至汽缸頭14時，可使第1突出部424及進氣凸輪263通過 第1凹部144，使排氣凸輪264通過第2凹部145，使樞銷支持部423通過第3凹部146。因此，可避免第1突出部424、進氣凸輪263、排氣凸輪264、及樞銷支持部423與第1軸承支持孔143干涉。 The first bearing support hole 143 in the cylinder head 14 includes a first recessed portion 144, a second recessed portion 145, and a third recessed portion 146. Therefore, when the cam shaft 26, the pressure reducing mechanism 40, and the first bearing 27 are integrally mounted to the cylinder head 14, the first protruding portion 424 and the intake cam 263 can pass through The first recessed portion 144 passes the exhaust cam 264 through the second recessed portion 145 and the pivot pin support portion 423 passes through the third recessed portion 146. Therefore, it is possible to prevent the first protruding portion 424, the intake cam 263, the exhaust cam 264, and the pivot pin support portion 423 from interfering with the first bearing support hole 143.

又，第1凹部144、第2凹部145、及第3凹部146位於相對於第1軸承支持孔143之中心與曲軸11為相反的一側。因此，可抑制較大地承受來自曲軸11之負載之第1軸承支持孔143之曲軸11側的部分之支持強度之降低。 The first recessed portion 144, the second recessed portion 145, and the third recessed portion 146 are located on the side opposite to the crankshaft 11 with respect to the center of the first bearing support hole 143. Therefore, it is possible to suppress a decrease in the support strength of the portion on the crankshaft 11 side of the first bearing support hole 143 that greatly receives the load from the crankshaft 11.

以上，對本發明之一實施形態進行了說明，但本發明並不限定於上述實施形態，可於不脫離發明之主旨之範圍內進行各種變更。 As mentioned above, although one Embodiment of this invention was described, this invention is not limited to the said embodiment, Various changes are possible in the range which does not deviate from the meaning of invention.

配重體之形狀並不限於上述實施形態之形狀，亦可進行變更。例如，圖17係表示第1變化例之配重體42之圖。如圖17所示，亦可使第2部分422包含第2突出部427。自凸輪軸26之軸線方向觀察，第2突出部427較第1軸承27之外周面更朝外側突出。第1突出部424之體積大於第2突出部427之體積。於此情形時，與上述實施形態同樣地，可使配重體42之重心G1進一步遠離凸輪軸26之旋轉中心C1。又，與第2突出部427之體積大於第1突出部424之體積之情形相比，可使配重體42之重心G1之位置靠近配重體42之旋轉中心C2。 The shape of the weight is not limited to the shape of the embodiment described above, and may be changed. For example, FIG. 17 is a diagram showing a weight body 42 according to a first modification. As shown in FIG. 17, the second portion 422 may include the second protruding portion 427. When viewed from the axial direction of the camshaft 26, the second protruding portion 427 protrudes further outward than the outer peripheral surface of the first bearing 27. The volume of the first protrusion 424 is larger than the volume of the second protrusion 427. In this case, the center of gravity G1 of the weight body 42 can be further separated from the rotation center C1 of the cam shaft 26 in the same manner as in the above-described embodiment. In addition, compared with the case where the volume of the second protruding portion 427 is larger than the volume of the first protruding portion 424, the center of gravity G1 of the weight body 42 can be brought closer to the rotation center C2 of the weight body 42.

圖18係表示第2變化例之配重體42之圖。如圖18所示，配重體42亦可包含配置於第3區域A3之第3部分428。自凸輪軸26之軸線方向觀察，第3部分428之外周面位於較第1軸承27之外周面更靠內側處。凸輪軸26之軸線方向上之第1突出部424之最大厚度大於凸輪軸26之軸線方向上之第2配重體部48之最大厚度。於此情形時，與自凸輪軸26之軸線方向觀察，第3部分428之外周面位於較第1軸承27之外周面更靠外側之情形相比，可使配重體42之重心G1遠離凸輪軸26之旋轉中心C1。 FIG. 18 is a view showing a weight body 42 according to a second modification. As shown in FIG. 18, the weight body 42 may include a third portion 428 arranged in the third area A3. Viewed from the axial direction of the camshaft 26, the outer peripheral surface of the third portion 428 is located more inward than the outer peripheral surface of the first bearing 27. The maximum thickness of the first protruding portion 424 in the axial direction of the cam shaft 26 is larger than the maximum thickness of the second weight body portion 48 in the axial direction of the cam shaft 26. In this case, the center of gravity G1 of the weight body 42 can be moved away from the cam as compared with the case where the outer peripheral surface of the third portion 428 is located further outside than the outer peripheral surface of the first bearing 27 as viewed from the axial direction of the camshaft 26. The rotation center C1 of the shaft 26.

或，亦可使配重體之周向長度較上述實施形態之配重體42短。 例如，亦可將第1配重體部47之周向端部471配置於第1區域A1。 Alternatively, the circumferential length of the weight body may be made shorter than the weight body 42 of the above embodiment. For example, the circumferential end portion 471 of the first weight body portion 47 may be disposed in the first region A1.

圖19係表示第3變化例之配重體42之圖。如圖19所示，第3部分428亦可包含第3突出部429。自凸輪軸26之軸線方向觀察，第3突出部429較第1軸承27之外周面更朝外側突出。第1突出部424之體積大於第3突出部429之體積。於此情形時，與第3突出部429之體積大於第1突出部424之體積之情形相比，可使配重體42之重心G1遠離凸輪軸26之旋轉中心C1。 FIG. 19 is a view showing a weight body 42 according to a third modification. As shown in FIG. 19, the third portion 428 may include a third protruding portion 429. When viewed from the axial direction of the cam shaft 26, the third protruding portion 429 protrudes further outward than the outer peripheral surface of the first bearing 27. The volume of the first protrusion 424 is larger than the volume of the third protrusion 429. In this case, compared with the case where the volume of the third protrusion 429 is larger than the volume of the first protrusion 424, the center of gravity G1 of the weight body 42 can be separated from the rotation center C1 of the cam shaft 26.

圖20係表示第4變化例之配重體42之圖。如圖20所示，亦可自凸輪軸線方向觀察，使樞銷支持部423位於較第1軸承27之外周面更靠內側處。 FIG. 20 is a view showing a weight body 42 according to a fourth modification. As shown in FIG. 20, the pivot pin support portion 423 may be positioned further inside than the outer peripheral surface of the first bearing 27 when viewed from the cam axis direction.

圖21係表示第5變化例之配重體42之圖。如圖21所示，亦可自凸輪軸線方向觀察，使樞銷46位於較排氣凸輪264之基圓266更靠內側處。即，亦可自凸輪軸線方向觀察，使配重體42之旋轉中心C2位於較排氣凸輪264之基圓266更靠內側處。 FIG. 21 is a view showing a weight body 42 according to a fifth modification. As shown in FIG. 21, the pivot pin 46 can also be viewed from the direction of the cam axis so that the pivot pin 46 is located further inside than the base circle 266 of the exhaust cam 264. In other words, the rotation center C2 of the weight body 42 may be located further inside than the base circle 266 of the exhaust cam 264 as viewed from the cam axis direction.

圖22係表示第6變化例之配重體42之圖。如圖22所示，亦可自凸輪軸線方向觀察，使配重體42之旋轉中心C2位於較排氣凸輪264之凸輪凸部267更靠外側處。又，亦可使樞銷46之整體位於較排氣凸輪264之外周面更靠外側處。 FIG. 22 is a view showing a weight body 42 according to a sixth modification. As shown in FIG. 22, the rotation center C2 of the weight body 42 can also be viewed further from the cam axis direction than the cam convex portion 267 of the exhaust cam 264. In addition, the entirety of the pivot pin 46 may be positioned further outside than the outer peripheral surface of the exhaust cam 264.

於上述實施形態中，配重體42係經由凸緣41支持於凸輪軸26，但亦可將配重體直接支持於凸輪軸。於上述實施形態中，凸緣41係與凸輪軸分開，且藉由壓入固定於凸輪軸，但亦可藉由壓入以外之固定方法而固定。或，亦可使凸緣與凸輪軸一體地形成。 In the above embodiment, the weight body 42 is supported by the cam shaft 26 via the flange 41, but the weight body may be directly supported by the cam shaft. In the above embodiment, the flange 41 is separated from the camshaft and fixed to the camshaft by press-fitting, but may be fixed by a fixing method other than press-fitting. Alternatively, the flange may be formed integrally with the camshaft.

亦可省略配重體之內輪接觸部。亦可省略配重體之收納部。即，亦可將回復彈簧配置於配重體以外之位置。 The inner wheel contact portion of the weight body may be omitted. The storage portion of the weight body may be omitted. That is, the return spring may be disposed at a position other than the weight body.

於上述實施形態中，係舉出速克達型機車來作為車輛之例，但本發明之車輛並不限於速克達型，亦可為運動型、越野型、輕型等其 他種類之機車。此處，機車並不限於二輪，包含三輪之車輛。又，本發明之車輛較佳為機車、全地形車輛(ALL-TERRAIN VEHICLE)、或雪上摩托車等跨坐型車輛，但亦可為跨坐型車輛以外之車輛。 In the above-mentioned embodiment, a scooter type locomotive is used as an example of the vehicle, but the vehicle of the present invention is not limited to the scooter type, and may be a sports type, an off-road type, a light type, or the like Other types of locomotives. Here, the locomotive is not limited to two-wheeled vehicles, and includes three-wheeled vehicles. The vehicle of the present invention is preferably a straddle type vehicle such as a locomotive, an all-terrain vehicle (ALL-TERRAIN VEHICLE), or a snowmobile, but may be a vehicle other than a straddle type vehicle.

此處所使用之用語及表達係用以進行說明者，而非用以限定性地進行解釋者。須認識到：亦不排除此處所示且所述之特徵事項之所有均等物，亦容許本發明之申請專利範圍內之各種變化。本發明能夠以許多不同之形態而實現。應將該揭示視為提供本發明之原理之實施形態者。於理解該等實施形態並非意欲將本發明限定於此處所記載且/或圖示之較佳之實施形態者之前提下，將實施形態記載於此。並不限定於此處所記載之實施形態。本發明亦包含業者可基於該揭示而認識到之包含均等之要素、修正、刪除、組合、改良、及/或變更之所有實施形態。申請專利範圍之限定事項應基於該申請專利範圍所使用之用語廣義地進行解釋，不應限定於本說明書或本案之審查過程中所記載之實施形態。 The terms and expressions used herein are for the purpose of explanation and not for the purpose of limiting interpretation. It must be recognized that all equivalents of the characteristic matters shown and described herein are not excluded, and variations within the scope of the patent application of the present invention are also allowed. The invention can be implemented in many different forms. This disclosure should be regarded as an embodiment providing the principle of the present invention. Prior to understanding these embodiments, it is not intended to limit the present invention to the preferred embodiments described and / or illustrated herein, and the embodiments are described here. It is not limited to the embodiment described here. The present invention also includes all embodiments which can be recognized by the supplier based on the disclosure, including equal elements, corrections, deletions, combinations, improvements, and / or changes. The matters limiting the scope of the patent application shall be interpreted broadly based on the terms used in the scope of the patent application, and shall not be limited to the implementation forms described in the examination process of this specification or this case.

27‧‧‧第1軸承 27‧‧‧The first bearing

42‧‧‧配重體 42‧‧‧ weight

47‧‧‧第1配重體部 47‧‧‧ 1st weight body

48‧‧‧第2配重體部 48‧‧‧Second weight body

272‧‧‧外輪 272‧‧‧outer

421‧‧‧第1部分 421‧‧‧Part 1

422‧‧‧第2部分 422‧‧‧Part 2

423‧‧‧樞銷支持部 423‧‧‧ pivot pin support department

424‧‧‧第1突出部 424‧‧‧ 1st protrusion

424a‧‧‧較近之部分 424a‧‧‧More recent

424b‧‧‧較遠之部分 424b

426‧‧‧內輪接觸部 426‧‧‧Inner wheel contact

A1‧‧‧第1區域 A1‧‧‧Area 1

A2‧‧‧第2區域 A2‧‧‧ Zone 2

A3‧‧‧第3區域 A3‧‧‧Region 3

A4‧‧‧第4區域 A4‧‧‧Area 4

C1‧‧‧凸輪軸26之旋轉中心 C1‧‧‧ center of rotation of camshaft 26

C2‧‧‧配重體42之旋轉中心 C2‧‧‧ weight center of rotation 42

G1‧‧‧配重體42之重心 Center of gravity of G1‧‧‧ weight body 42

G2‧‧‧無第1突出部424之情形時之配重體42之重心 G2 ‧‧‧ Center of gravity of weight body 42 without first protrusion 424

X‧‧‧橫軸 X‧‧‧ horizontal axis

Y‧‧‧縱軸 Y‧‧‧Vertical axis

Claims (11)

一種引擎，其包括：汽缸頭；排氣閥，其收納於上述汽缸頭；閥動機構，其使上述排氣閥打開及閉合；凸輪軸，其藉由與上述閥動機構接觸，而驅動上述閥動機構；第1軸承，其將上述凸輪軸可旋轉地支持於上述汽缸頭；及減壓機構，其配置於上述凸輪軸之軸線方向上之兩端部之間；上述減壓機構包括：配重體，其相對於上述凸輪軸可於閉合狀態與打開狀態之間旋轉地受到支持；回復彈簧，其以使上述配重體自上述打開狀態恢復至上述閉合狀態之方式對該配重體彈壓；及減壓凸輪，其以如下方式而設置，即，當上述配重體為上述閉合狀態時，與上述閥動機構接觸，當上述配重體為上述打開狀態時，不與上述閥動機構接觸；自上述凸輪軸之軸線方向觀察，將通過上述凸輪軸之旋轉中心與上述配重體之旋轉中心之直線設為縱軸，將與上述縱軸正交且通過上述凸輪軸之旋轉中心之直線設為橫軸，將平行於上述縱軸之方向中之自上述凸輪軸之旋轉中心朝向上述配重體之旋轉中心之方向設為第1縱方向，將平行於上述橫軸之方向中之一者設為第1橫方向，自上述凸輪軸之軸線方向觀察，上述配重體之重心配置於第1 區域，該第1區域相對於上述橫軸位於上述第1縱方向，並且相對於上述縱軸位於上述第1橫方向，上述配重體包含第1部分，自上述凸輪軸之軸線方向觀察，該第1部分配置於上述第1區域，且於上述閉合狀態下，上述第1部分包含第1突出部，自上述凸輪軸之軸線方向觀察，該第1突出部較上述第1軸承之外周面更朝外側突出。 An engine includes: a cylinder head; an exhaust valve housed in the cylinder head; a valve operating mechanism that opens and closes the exhaust valve; and a camshaft that drives the valve by contacting the valve operating mechanism A valve mechanism; a first bearing rotatably supporting the camshaft on the cylinder head; and a pressure reducing mechanism disposed between both ends of the camshaft in the axial direction; the pressure reducing mechanism includes: The weight body is rotatably supported relative to the camshaft between a closed state and an open state; a return spring restores the weight body to the weight body in a manner that restores the weight body from the open state to the closed state. Spring pressure; and a decompression cam provided in such a manner that, when the weight body is in the closed state, it is in contact with the valve moving mechanism, and when the weight body is in the open state, it is not moved with the valve Mechanism contact; viewed from the axial direction of the camshaft, a straight line passing through the rotation center of the camshaft and the rotation center of the weight body is set as a vertical axis, and is orthogonal to the vertical axis and passes through A straight line of the rotation center of the cam shaft is set as a horizontal axis, and a direction from the rotation center of the cam shaft toward the rotation center of the weight body in a direction parallel to the vertical axis is set as a first longitudinal direction, and is parallel to One of the directions of the horizontal axis is set to the first horizontal direction. When viewed from the axial direction of the cam shaft, the center of gravity of the weight body is arranged at the first The first region is located in the first vertical direction with respect to the horizontal axis and in the first horizontal direction with respect to the vertical axis, and the weight body includes a first portion, viewed from the axial direction of the camshaft, the The first portion is disposed in the first region, and in the closed state, the first portion includes a first protruding portion. When viewed from the axial direction of the camshaft, the first protruding portion is more than the outer peripheral surface of the first bearing. Protrudes outward. 如請求項1之引擎，其中將與上述第1縱方向相反之方向設為第2縱方向，上述配重體進而包含第2部分，自上述凸輪軸之軸線方向觀察，上述第2部分配置於第2區域，該第2區域相對於上述橫軸位於上述第2縱方向，並且相對於上述縱軸位於上述第1橫方向，且自上述凸輪軸之軸線方向觀察，上述第2部分之外周面位於較上述第1軸承之外周面更靠內側處。 For example, the engine of claim 1, wherein the direction opposite to the first longitudinal direction is set to the second longitudinal direction, the weight body further includes a second portion, and the second portion is disposed in the axial direction of the camshaft. A second region located in the second longitudinal direction with respect to the horizontal axis and in the first horizontal direction with respect to the vertical axis, and viewed from the axial direction of the cam shaft, the outer peripheral surface of the second portion It is located inward from the outer peripheral surface of the first bearing. 如請求項1之引擎，其中將與上述第1縱方向相反之方向設為第2縱方向，上述配重體進而包含第2部分，自上述凸輪軸之軸線方向觀察，上述第2部分配置於第2區域，該第2區域相對於上述橫軸位於上述第2縱方向，並且相對於上述縱軸位於上述第1橫方向，上述第2部分包含第2突出部，自上述凸輪軸之軸線方向觀察，該第2突出部較上述第1軸承之外周面更朝外側突出，且上述第1突出部之體積大於上述第2突出部之體積。 For example, the engine of claim 1, wherein the direction opposite to the first longitudinal direction is set to the second longitudinal direction, the weight body further includes a second portion, and the second portion is disposed in the axial direction of the camshaft. A second region located in the second vertical direction with respect to the horizontal axis and in the first horizontal direction with respect to the vertical axis, the second portion including a second protruding portion from the axial direction of the cam shaft It is observed that the second protruding portion protrudes more outwardly than the outer peripheral surface of the first bearing, and the volume of the first protruding portion is greater than the volume of the second protruding portion. 如請求項2之引擎，其中上述凸輪軸之軸線方向上之上述第1突出部之最大厚度大於上 述凸輪軸之軸線方向上之上述第2部分之最大厚度。 The engine of claim 2, wherein the maximum thickness of the first protrusion in the axial direction of the camshaft is greater than The maximum thickness of the second part in the axial direction of the camshaft is described. 如請求項1之引擎，其中將與上述第1縱方向相反之方向設為第2縱方向，將與上述第1橫方向相反之方向設為第2橫方向，上述配重體進而包含第3部分，自上述凸輪軸之軸線方向觀察，上述第3部分配置於第3區域，該第3區域相對於上述橫軸位於上述第2縱方向，並且相對於上述縱軸位於上述第2橫方向，且自上述凸輪軸之軸線方向觀察，上述第3部分之外周面位於較上述第1軸承之外周面更靠內側處。 For example, the engine of claim 1, wherein a direction opposite to the first vertical direction is set as a second vertical direction, and a direction opposite to the first horizontal direction is set as a second horizontal direction, and the weight body further includes a third In part, viewed from the axial direction of the camshaft, the third portion is disposed in a third region, the third region is located in the second vertical direction with respect to the horizontal axis, and is located in the second horizontal direction with respect to the vertical axis, When viewed from the axial direction of the camshaft, the outer peripheral surface of the third portion is located more inward than the outer peripheral surface of the first bearing. 如請求項1之引擎，其中將與上述第1縱方向相反之方向設為第2縱方向，將與上述第1橫方向相反之方向設為第2橫方向，上述配重體進而包含第3部分，自上述凸輪軸之軸線方向觀察，上述第3部分配置於第3區域，該第3區域相對於上述橫軸位於上述第2縱方向，並且相對於上述縱軸位於上述第2橫方向，自上述凸輪軸之軸線方向觀察，上述第3部分包含較上述第1軸承之外周面更朝外側突出之第3突出部，且上述第1突出部之體積大於上述第3突出部之體積。 For example, the engine of claim 1, wherein a direction opposite to the first vertical direction is set as a second vertical direction, and a direction opposite to the first horizontal direction is set as a second horizontal direction, and the weight body further includes a third In part, viewed from the axial direction of the camshaft, the third portion is disposed in a third region, the third region is located in the second vertical direction with respect to the horizontal axis, and is located in the second horizontal direction with respect to the vertical axis, Viewed from the axial direction of the camshaft, the third portion includes a third protruding portion that protrudes more outwardly than the outer peripheral surface of the first bearing, and the volume of the first protruding portion is greater than the volume of the third protruding portion. 如請求項5之引擎，其中上述凸輪軸之軸線方向上之上述第1突出部之最大厚度大於上述凸輪軸之軸線方向上之上述第3部分之最大厚度。 The engine of claim 5, wherein the maximum thickness of the first protruding portion in the axial direction of the camshaft is greater than the maximum thickness of the third portion in the axial direction of the camshaft. 如請求項1之引擎，其中自上述凸輪軸之軸線方向觀察，上述第1突出部包含：較近之部分，其於上述第1軸承之周向上，較無上述第1突出部時之上 述配重體之重心之位置更靠近上述配重體之旋轉中心；及較遠之部分，其於上述第1軸承之周向上，較無上述第1突出部時之上述配重體之重心之位置更遠離上述配重體之旋轉中心，且上述較近之部分大於上述較遠之部分。 If the engine of claim 1 is viewed from the axial direction of the camshaft, the first protruding portion includes: a closer portion, which is higher in a circumferential direction of the first bearing than when there is no first protruding portion; The position of the center of gravity of the weight body is closer to the center of rotation of the weight body; and the farther part is, in the circumferential direction of the first bearing, less than the center of gravity of the weight body without the first protrusion. The position is farther from the center of rotation of the weight body, and the closer part is larger than the farther part. 如請求項1之引擎，其中上述配重體包含樞銷支持部，上述減壓機構進而包含安裝於上述樞銷支持部之樞銷，上述配重體經由上述樞銷可相對於上述凸輪軸旋轉地受到支持，且上述凸輪軸之軸線方向上之上述第1突出部之厚度大於上述凸輪軸之軸線方向上之上述樞銷支持部之厚度。 For example, the engine of claim 1, wherein the weight body includes a pivot pin support portion, the decompression mechanism further includes a pivot pin mounted on the pivot pin support portion, and the weight body is rotatable relative to the cam shaft via the pivot pin. The ground is supported, and the thickness of the first protruding portion in the axial direction of the cam shaft is greater than the thickness of the pivot pin supporting portion in the axial direction of the cam shaft. 如請求項1之引擎，其進而包括：曲軸；及凸輪鏈條，其捲繞於上述曲軸與上述凸輪軸；上述汽缸頭包含支持上述第1軸承之第1軸承支持孔，上述第1軸承支持孔包含可使上述第1突出部通過之第1凹部，且上述第1凹部之至少一部分位於相對於上述第1軸承支持孔之中心與上述曲軸為相反的一側。 The engine according to claim 1, further comprising: a crankshaft; and a cam chain wound around the crankshaft and the camshaft; the cylinder head includes a first bearing support hole supporting the first bearing, and the first bearing support hole It includes a first recessed portion through which the first protruding portion can pass, and at least a portion of the first recessed portion is located on the side opposite to the crankshaft with respect to the center of the first bearing support hole. 一種車輛，其包含如請求項1至10中任一項之引擎。 A vehicle comprising an engine as claimed in any one of claims 1 to 10.