201126081 六、發明說明： 【發明所屬之技術領域】 本發明係有關於一種液壓張緊裝置，特別是有關於一 種應用於動力裝置或傳動裝置中之液壓張緊裝置。 【先前技術】201126081 VI. Description of the Invention: [Technical Field] The present invention relates to a hydraulic tensioning device, and more particularly to a hydraulic tensioning device applied to a power device or a transmission device. [Prior Art]
液壓張緊裝置一般係應用在動力系統或傳動系統中。 例如.用來傳遞動力糸統驅動轴之動力的循環彈性構件， 為了使得動力的傳遞順暢，並避免循環彈性構件的張力變 化所1¾成的震動，故通常於循環彈性構件的鬆弛侧設置一 液壓張緊裝置，並透過一液壓通道連接液壓槽與液壓泵（例 如油壓泵(Oil Pump)形成液壓張緊裝置組，藉此自動地調整 循環彈性構件的張力。 在美國專利號US 5,346,436中，Francis J. Hunter等人 揭露一般液壓張緊裝置包含有本體、活塞、空氣閥及彈簧， "中上氣閥主要作用在提供一通道以連通活塞頂端之貫穿 =以及活塞凹陷部之空間，藉由空氣閥之通道，使得活塞 番、本體之間所包含之液壓油中的氣體能夠排出液壓張緊裝 、之外。其主要技術特徵在於空氣閥上通道的設計，其中 ^道係叹置在空氣閥的頂面，利用彎曲幾何形狀來增加空 上通道的距離。但是，此空氣閥的通道料讓氣體的 排出較不順暢。 【發明内容】 本發明之目的係在提供__種液壓張緊裝置，在液壓張 201126081 面設置第三凹陷部，以及連通第三凹 2帛―胃穿孔的通道部，讓㈣油巾所包含之 :體排出更順暢’並藉此增加液 =需流經的距離，減少過多的液壓油㈣液壓= 之丁之優點為’空氣閥之頂面可不必與活塞凹陷部 面5也能產生功效，故空氣閥可做模組化生產，並 且適用於各形式之張緊裝置。 根據本發明之-實施例，提供一種液壓張 ，液壓張緊裝置包括：具有第—凹陷部的本體、底面具有 凹陷部的活塞、容設於第二凹陷部的空氣閥、彈性構 件、液壓通道部以及逆止閥。第—凹陷部制以容設提供 液壓之液體。而活塞頂面具有第—貫穿孔，其中活塞射 移動地容設在第-凹陷部，並可凸伸於第—凹陷部之外。 而空氣閥具有相對的頂面與底面，其中頂面上包括有至少 一第二凹陷部以及連通第三凹陷部與與活塞第一貫穿孔的 至少-通道部，第三凹陷部之底面更凹設有用以連通第三 凹陷部與空氣狀底面較少_帛二貫穿孔。彈性構件之 一端與空氣閥接觸。液壓通道用以連通本體第一凹陷部與 液體之供應裝置。逆止閥用以防止液體逆流至供應裝置^ 【實施方式】 以下說明内容中，相似元件將以相同編號表示。 請參照第1A圖，其係繪示根據本發明之一實施例之 201126081 液壓張緊裝置的剖面示意圖。液壓張緊裝置100包括本體 102、活塞104、空氣閥200、彈性構件108及逆止閥110， 而本體102中更具有液壓通道112。液壓張緊裝置100以 液壓通道112與液壓管路（未繪示）相連接，其中液壓管路又 與液壓槽（未繪示）互相連通，而液壓槽則與液壓泵（未繪示) 互相連通，形成液壓張緊裝置組。在液壓張緊裝置組中， 主要係利用液壓泵將液壓槽中之液體（例如液壓油）透過液 壓管路以及液壓通道112輸送至液壓張緊裝置100的本體 102 中。 •在液壓張緊裝置100中，本體102具有第一凹陷部 102a，在此實施例中，第一凹陷部102a具有底面102aa及 側面102ab，其中第一凹陷部102a係用來容設前述來自於 液壓槽的液體，此液體主要係用來傳遞液壓泵之壓力，藉 此提供活塞104所需的推力。 在此實施例中，活塞104的底面104a具有第二凹陷部 104b，其中第二凹陷部104b包含底面104ba與側面104bb， 而活塞104之頂面104c具有第一貫穿孔104d，其中活塞 • 104容設在本體102的第一凹陷部102a中，活塞104之第 二凹陷部104b與本體102之第一凹陷部102a共同形成容 置來自於液壓槽之液體的空間，另外，活塞104的頂面104c 可凸伸於本體102的第一凹陷部102a之外。當活塞104受 到本體102之第一凹陷部102a中容設之液體的推動時，活 塞104可沿著本體102之第一凹陷部102a的軸向朝遠離本 體102之方向移動，藉此維持與活塞104之頂面104c接觸 之循環彈性構件（未繪示）的張力。 201126081 在本實施例中’空氣閥200係容設在活塞104的第二 凹陷部104b之中。 請同時參照第1B及ic圖，其中第1B圖係為第1A圖 之空氣閥200之上視圖’第ic圖係繪示沿著第1B圖中線 AA’剖切之剖面示意圖。空氣閥200具有相對的頂面202 與底面204以及一侧面205，其中於頂面202上設置有至 少一第三凹陷部206以及一通道部212，其中通道部212 係用以連通第三凹陷部2〇6與活塞1〇4的第一貫穿孔i〇4d。 在本實施例中，第三凹陷部206係為環狀，惟在其他 貫施例中，第三凹陷部2〇6可具有其他幾何形狀，例如多 邊形等。第三凹陷部206係環繞凹設於空氣閥2〇〇的頂面 202之上，且第三凹陷部2〇6之底面在本實施例中係規則 地设置有六個環繞第三凹陷部2〇6之第二貫穿孔21〇，第 一貫穿孔210係用以連通第三凹陷部2〇6與空氣閥2〇〇的 底面2〇4。 爾空氣閥200的頂面2〇2和側面205與活塞1〇4之第 二凹陷部104b的底面l〇4ba與側面1〇4bb緊密配合時，包 ，在第一凹陷部102a的液體所包含的氣體，係依序經由空 氣間00的底面204之第二貫穿孔21 〇，再到第三凹陷部 206，經通道部212之後，經由活塞104之第一貫穿孔104d 而排出液壓張緊裝置100之外。 如第1A圖所示，在本實施例中，彈性構件1〇8係一 彈簧但並不以此為限。彈性構件108容設於活塞1〇4的 第二凹陷部104b中，彈性構件108的其中一端與空氣閥 200接觸’另一端置於活塞104的第二凹陷部i〇4b内。彈 201126081 性構件108主要作用在於提供活塞104基本的推力，藉此 維持與活塞104之頂面丨〇4c接觸之循環彈性構件（未繪示） 的張力。 請參照第2A及2B圖，其係分別繪示根據本發明之另 一實施例之空氣閥300的上視圖，以及沿著第2A圖中線 BB’剖切之剖面示意圖。在此實施例中，空氣閥3〇〇相關結 構、變化以及與活塞之間的相對關係均類似於空氣閥2〇〇 之結構與關係，故以下僅就差異部分加以說明，類似部分 即不再贅述。為了進一步提升流經活塞1〇4之第一貫穿孔 l〇4d之液體所包含氣體的順暢性，空氣閥3〇〇除對應於空 氣閥200設有第三凹陷部206外，更增設一第四凹陷部 208，此第四凹陷部208在本實施例中與第三凹陷部206係 為一同心環，且直徑小於第三凹陷部2〇6。另外，第四凹 陷部208也相同於第三凹陷部2〇6，於底面3〇4規則地設 有六個環繞第四凹陷部2〇8之第二貫穿孔210，且第四凹 陷部208與第三凹陷部2〇6具有相同的水平底面；而第四 凹陷部208與第三凹陷部2〇6則具有相同之頂面3〇2，但 第二凹陷部206之一側璧高度係高於第四凹陷部208之一 側璧。使第三凹陷部206、第四凹陷部2〇8與空氣闕300 之頂面302之間形成一通道部2丨2，此通道部2丨2係用以 連通第四凹陷部208與三凹陷部2〇6,並與第一貫穿孔l〇4d 連通。而第三凹陷部206與第四凹陷部208之間所共有之 侧壁高度係相異於第四凹陷部2〇8之另一侧壁，並低於空 氣閥300之頂面302。 請參照第3A及3B圖，其係分別繪示根據本發明之另 201126081 -實施例之空氣閥400的上視圖，以及沿著第 CC’剖切之剖面示意圖。在此實施例 、、- 構、變化以及與活塞之間的相對關係均類 之結構與關係，故以下僅就差異部分加以說明，= =再贅述。在^氣閥40"，第三凹陷部2()6二2 ^之間的頂面與空氣闕4〇〇之頂面4〇2齊二並： :=二凹陷部祕之底面1〇4ba緊密配合通道部扣 二Si陷部2〇6與第四凹陷部2〇8之間的部分頂面搬 而形成-矩形溝槽狀，連通第三凹陷部施與 陷部208並與i〇4d連通。 請參照第4A及4B圖，其係分別緣示根據本發明之另 施例之空氣閥500的上視圖，以及沿著第4A圖中線 广剖切之剖面示意圖。在此實施例中，空氣閥5〇"目關 •、。構變化以及與活塞之間的相對關係均類似於空氣閥侧 ^結構與關係’故以下僅就差異部分加以說明，類似部分 ^不再头述。於空氣閥500巾，第三凹陷部2〇6之外週邊 ，質為-圓形且呈環狀’内週邊係由多個弧狀加以組合所 形成，幾何形狀(但並不以此形狀為限），目的是為增加第 —凹陷部206之空間，讓液體所包含之氣體容易在此聚 集二^四凹陷部208設於空氣閥5〇〇之圓心處，可直接與 ^貝穿孔l〇4d連通，而其底面凹陷程度較淺於第三凹陷 I5 206而在其他特定之實施例中，第四凹陷部208底面 凹陷程度亦可較深於第三凹陷部2〇6。 - =外’第四凹陷部208於本實施例中並未於底面設置 第一貝穿孔210，且在本實施例中，第四凹陷部2〇8與第 9 ⑶ 201126081 三凹陷部206間之頂面地更形成—通道部2i2，藉以連 通第三凹陷部施與第四凹陷部咖。其中通道部^在 第三凹陷部施與第四凹陷部施之間，是呈現—槽溝狀， 使聚集在第三凹陷部2G6之液體所包含的氣體，僅能經由 第三凹陷部206之内週邊料的位置進入通道部212，再 進入第四凹陷部施中，最後經由活塞刚之第—貫穿孔 104d而排出液塵張緊裝置1 〇〇之外。 請參照第4C ® ’於本實施财，空氣閥於底面504 更突設有-凸出部214’凸出部214係位在如第丨圖所示 之活塞H)4的第二凹陷部1〇仆之中。而凸出部214主要作 用在於降低活塞104之第二凹陷部1〇4b與本體1()2之第一 凹陷部102a間可容置液體的空間’藉此減少建立油壓所需 的時間。 上述已大略描述多個實施例的特徵，以使得熟悉此技 藝者能夠更了解與其對應的詳細敘述。熟悉此技藝者將可 體會到，洲本減作為基礎可料或修改其他程序及結 構，，達到本說明書所介紹之實施例的相同目的及/或優 點。熟悉此技#者亦可了解到在不脫離本揭露之精神及範 圍之等價的架構’以及在不脫離本揭露之精神及範圍内， 當可作各種的更動、替代和潤飾。 【圖式簡單說明】 為了能夠對本發明之觀點有較佳之理解，請參照上述 明並配合相應之圖式。要強調的是 工業之 &準常規’關中之各種特徵並未依比崎示。事實上， 201126081 為清楚說明上述實施例，可任意地放大或縮小各種特徵之 尺寸。相關圖式内容說明如下。 第1A圖係繪示根據本發明之一實施例之液壓張緊裝 置的剖面示意圖。 第1B圖係繪示第1A圖之空氣閥的俯視示意圖。 第1C圖係繪示沿著第1B圖中線AA’剖切之剖面示 意圖。 第2A係繪示根據本發明之另一實施例之空氣閥的俯 I 視示意圖。 第2B圖係繪示沿著第2A圖中線BB’剖切之剖面示 意圖。 第3A係繪示根據本發明之另一實施例之空氣閥的俯 視示意圖。 第3B圖係繪示沿著第3A圖中線CC’剖切之剖面示 意圖。 第4A係繪示根據本發明之另一實施例之空氣閥的俯 φ 視示意圖。 第4B圖係繪示沿著第4A圖中線DD’剖切之剖面示 意圖。 第4C圖係繪示根據本發明之另一實施例之空氣閥的 剖面示意圖。 102 :本體 【主要元件符號說明】 100 :液壓張緊裝置 201126081 102a :第一凹陷部 204 ： 底面 102aa :底面 205 ： 側面 102ab :側面 206 ： 第三凹陷部 104 :活塞 208 ： 第四凹陷部 104a :底面 210 ： 第二貫穿孔 104b :第二凹陷部 212 ： 通道部 104ba :底面 214 ： 凸出部 104bb :側面 300 : 空氣閥 104c :頂面 302 ： 頂面 104d :第一貫穿孔 304 ： 底面 108 :彈性構件 400 ： 空氣閥 110 :逆止閥 402 ： 頂面 112 :液壓通道 500 ： 空氣閥 200 :空氣閥 502 ： 頂面 202 :頂面 504 ： 底面Hydraulic tensioning devices are typically used in power systems or transmission systems. For example, a cyclic elastic member for transmitting the power of the power system drive shaft, in order to make the power transmission smooth and avoid the vibration of the cyclic elastic member, the hydraulic pressure is usually set on the slack side of the circulating elastic member. The tensioning device is coupled to the hydraulic pump via a hydraulic passage to form a hydraulic tensioning device with a hydraulic pump (e.g., an oil pump), thereby automatically adjusting the tension of the circulating elastic member. In U.S. Patent No. 5,346,436, Francis J. Hunter et al. disclose that a general hydraulic tensioning device includes a body, a piston, an air valve, and a spring. The upper middle air valve mainly functions to provide a passage to communicate the penetration of the top end of the piston and the space of the recessed portion of the piston. The passage of the air valve enables the gas in the hydraulic oil contained between the piston and the body to be discharged out of the hydraulic tensioning device. The main technical feature is the design of the passage on the air valve, wherein the channel is placed in the sigh The top surface of the air valve uses the curved geometry to increase the distance of the upper air passage. However, the passage of this air valve allows the gas to [Invention] The object of the present invention is to provide a hydraulic tensioning device, which is provided with a third recessed portion on the surface of the hydraulic pressure 201126081, and a passage portion that communicates with the third concave 2帛-stomach perforation. (4) The oil towel contains: the body discharge is smoother 'and thereby increase the liquid = the distance that needs to flow, reduce the excessive hydraulic oil (4) hydraulic pressure = the advantage of the 'air valve top surface does not have to be with the piston recessed surface 5 can also produce efficacy, so the air valve can be modularized and applied to various forms of tensioning device. According to an embodiment of the invention, a hydraulic tensioning device is provided, the hydraulic tensioning device comprising: having a first recess a body, a bottom surface having a recessed piston, an air valve accommodated in the second recess, an elastic member, a hydraulic passage portion, and a check valve. The first recessed portion is configured to receive a liquid for providing hydraulic pressure, and the top surface of the piston has a first through hole, wherein the piston is movably disposed in the first recess and protrudes beyond the first recess; and the air valve has opposite top and bottom surfaces, wherein the top surface includes at least one Two concave a recessed portion and a third recessed portion and at least a channel portion of the first through hole of the piston, wherein a bottom surface of the third recessed portion is recessed to communicate the third recessed portion and the airy bottom surface is less than two through holes. One end of the member is in contact with the air valve. The hydraulic passage is for connecting the first recess of the body with the liquid supply device. The check valve is for preventing the liquid from flowing back to the supply device. [Embodiment] In the following description, similar components will be the same Please refer to FIG. 1A, which is a cross-sectional view showing a hydraulic tensioning device according to an embodiment of the present invention. The hydraulic tensioning device 100 includes a body 102, a piston 104, an air valve 200, an elastic member 108, and The valve 110 is further provided with a hydraulic passage 112. The hydraulic tensioning device 100 is connected to a hydraulic line (not shown) by a hydraulic passage 112, which in turn is in contact with a hydraulic groove (not shown). The hydraulic grooves are connected to a hydraulic pump (not shown) to form a hydraulic tensioning device group. In the hydraulic tensioning device group, the liquid (e.g., hydraulic oil) in the hydraulic pressure tank is mainly supplied to the body 102 of the hydraulic tensioning device 100 through the hydraulic pressure line and the hydraulic passage 112 by means of a hydraulic pump. In the hydraulic tensioning device 100, the body 102 has a first recessed portion 102a. In this embodiment, the first recessed portion 102a has a bottom surface 102aa and a side surface 102ab, wherein the first recessed portion 102a is used to accommodate the aforementioned The liquid in the hydraulic tank, which is primarily used to transfer the pressure of the hydraulic pump, thereby providing the thrust required by the piston 104. In this embodiment, the bottom surface 104a of the piston 104 has a second recess 104b, wherein the second recess 104b includes a bottom surface 104ba and a side surface 104bb, and the top surface 104c of the piston 104 has a first through hole 104d, wherein the piston 104 In the first recessed portion 102a of the body 102, the second recessed portion 104b of the piston 104 and the first recessed portion 102a of the body 102 together form a space for accommodating the liquid from the hydraulic groove, and in addition, the top surface 104c of the piston 104 It may protrude beyond the first recess 102a of the body 102. When the piston 104 is pushed by the liquid contained in the first recess 102a of the body 102, the piston 104 can move along the axial direction of the first recess 102a of the body 102 away from the body 102, thereby maintaining the piston The tension of the cyclic elastic member (not shown) that the top surface 104c of 104 contacts. 201126081 In the present embodiment, the 'air valve 200 is housed in the second recessed portion 104b of the piston 104. Please refer to FIG. 1B and the ic diagram, wherein FIG. 1B is a top view of the air valve 200 of FIG. 1A. The ic diagram shows a cross-sectional view taken along line AA' of FIG. 1B. The air valve 200 has an opposite top surface 202 and a bottom surface 204 and a side surface 205. The top surface 202 is provided with at least a third recess portion 206 and a channel portion 212, wherein the channel portion 212 is configured to communicate with the third recess portion. 2〇6 and the first through hole i〇4d of the piston 1〇4. In the present embodiment, the third recessed portion 206 is annular, but in other embodiments, the third recessed portion 2〇6 may have other geometric shapes such as a polygon or the like. The third recessed portion 206 is disposed around the top surface 202 of the air valve 2〇〇, and the bottom surface of the third recessed portion 2〇6 is regularly provided with six surrounding third recessed portions 2 in this embodiment. The second through hole 21 of the crucible 6 is configured to communicate the third recessed portion 2〇6 with the bottom surface 2〇4 of the air valve 2〇〇. When the top surface 2〇2 and the side surface 205 of the air valve 200 and the bottom surface 104b of the second recessed portion 104b of the piston 1〇4 are closely fitted with the side surface 1〇4bb, the package includes the liquid in the first recessed portion 102a. The gas is sequentially discharged through the second through hole 21 of the bottom surface 204 of the air chamber 00, and then to the third recess portion 206, and after the passage portion 212, the hydraulic tensioning device is discharged through the first through hole 104d of the piston 104. Outside of 100. As shown in Fig. 1A, in the present embodiment, the elastic member 1 is a spring, but is not limited thereto. The elastic member 108 is accommodated in the second recessed portion 104b of the piston 1〇4, one end of the elastic member 108 is in contact with the air valve 200' and the other end is placed in the second recessed portion i4b of the piston 104. The spring 201126081 member 108 serves primarily to provide the basic thrust of the piston 104, thereby maintaining the tension of a circulating resilient member (not shown) that is in contact with the top surface 丨〇4c of the piston 104. Referring to Figures 2A and 2B, respectively, a top view of an air valve 300 according to another embodiment of the present invention, and a cross-sectional view taken along line BB' of Figure 2A are shown. In this embodiment, the air valve 3 〇〇 related structure, variation and relative relationship with the piston are similar to the structure and relationship of the air valve 2 ,, so the following only explains the difference, the similar part is no longer Narration. In order to further improve the smoothness of the gas contained in the liquid flowing through the first through hole l〇4d of the piston 1〇4, the air valve 3 is removed corresponding to the air valve 200 having the third recessed portion 206, and a first addition is provided. In the present embodiment, the fourth recessed portion 208 is concentric with the third recessed portion 206 and has a smaller diameter than the third recessed portion 2〇6. In addition, the fourth recessed portion 208 is also identical to the third recessed portion 2〇6, and the second through hole 210 surrounding the fourth recessed portion 2〇8 is regularly provided on the bottom surface 3〇4, and the fourth recessed portion 208 is further provided. The third recessed portion 2〇6 has the same horizontal bottom surface; and the fourth recessed portion 208 and the third recessed portion 2〇6 have the same top surface 3〇2, but one of the second recessed portions 206 has a side height It is higher than one side of the fourth recessed portion 208. A channel portion 2丨2 is formed between the third recessed portion 206 and the fourth recessed portion 2〇8 and the top surface 302 of the air 阙300, and the channel portion 2丨2 is configured to communicate with the fourth recessed portion 208 and the third recessed portion. The portion 2〇6 is in communication with the first through hole l〇4d. The height of the side wall shared between the third recessed portion 206 and the fourth recessed portion 208 is different from the other side wall of the fourth recessed portion 2〇8 and lower than the top surface 302 of the air valve 300. 3A and 3B are respectively a top view of an air valve 400 according to another embodiment of the present invention, and a cross-sectional view taken along line CC'. In this embodiment, the structure, the change, and the relative relationship with the piston are similar in structure and relationship, so the following only explains the difference, and == repeat. In the top of the gas valve 40 ", the third recess 2 () 6 2 2 ^ and the top surface of the air 阙 4 〇 2 〇 2 and two: : = two concave part of the bottom of the surface 1 〇 4ba a portion of the top surface between the channel portion buckles the second Si trap portion 2〇6 and the fourth recess portion 2〇8 is formed to be formed in a rectangular groove shape, and the third recess portion is connected to the trap portion 208 and i〇4d Connected. 4A and 4B are respectively a top view of an air valve 500 according to another embodiment of the present invention, and a schematic cross-sectional view taken along line 4A. In this embodiment, the air valve 5 " The structural change and the relative relationship with the piston are similar to the air valve side structure and relationship. Therefore, only the difference is explained below, and the similar part will not be described. In the air valve 500, the outer periphery of the third recessed portion 2〇6, the quality is a circular shape and the annular shape is formed by a plurality of arc-shaped inner circumferences, and the geometric shape (but not the shape) The purpose is to increase the space of the first recessed portion 206, so that the gas contained in the liquid is easily collected here. The recessed portion 208 is disposed at the center of the air valve 5〇〇, and can be directly connected with the hole. 4d is connected, and the bottom surface is recessed to a lesser extent than the third recess I5 206. In other specific embodiments, the fourth recessed portion 208 may be recessed to a greater extent than the third recess 2〇6. In the present embodiment, the first recessed portion 208 is not disposed on the bottom surface, and in the present embodiment, the fourth recessed portion 2〇8 and the ninth (3) 201126081 three recessed portion 206 are The top surface is further formed by the passage portion 2i2, thereby connecting the third recess portion to the fourth recess portion. The channel portion is disposed between the third recessed portion and the fourth recessed portion, and is formed in a groove shape, so that the gas contained in the liquid collected in the third recessed portion 2G6 can only pass through the third recessed portion 206. The position of the inner peripheral material enters the channel portion 212, enters the fourth recess portion, and finally exits the liquid dust tensioning device 1 through the first through hole 104d of the piston. Referring to FIG. 4C ® 'in this embodiment, the air valve is further protruded from the bottom surface 504 - the protrusion 214 is protruded from the second recess 1 of the piston H) 4 as shown in FIG. Among the servants. The projection 214 is mainly used to reduce the space in which the second recessed portion 1〇4b of the piston 104 and the first recessed portion 102a of the body 1 can accommodate liquid, thereby reducing the time required to establish the oil pressure. The features of the various embodiments have been described above in a manner to provide a more detailed description of the embodiments. It will be appreciated by those skilled in the art that the same purpose and/or advantages of the embodiments described in the present specification are achieved by the fact that the present invention can be used as a basis or modify other procedures and structures. It will be appreciated that those skilled in the art will be able to make various modifications, substitutions, and refinements without departing from the spirit and scope of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS In order to provide a better understanding of the present invention, reference is made to the above description and the corresponding drawings. It is important to emphasize that the various characteristics of the industrial & In fact, 201126081, to clearly illustrate the above embodiments, the dimensions of the various features can be arbitrarily enlarged or reduced. The relevant schema description is as follows. Fig. 1A is a schematic cross-sectional view showing a hydraulic tensioning device according to an embodiment of the present invention. Fig. 1B is a schematic plan view showing the air valve of Fig. 1A. Fig. 1C is a cross-sectional view taken along line AA' of Fig. 1B. Fig. 2A is a schematic cross-sectional view showing an air valve according to another embodiment of the present invention. Fig. 2B is a cross-sectional view taken along line BB' of Fig. 2A. Fig. 3A is a schematic plan view showing an air valve according to another embodiment of the present invention. Fig. 3B is a cross-sectional view taken along line CC' of Fig. 3A. Fig. 4A is a schematic view showing the air valve according to another embodiment of the present invention. Fig. 4B is a cross-sectional view taken along line DD' of Fig. 4A. Fig. 4C is a schematic cross-sectional view showing an air valve according to another embodiment of the present invention. 102: main body [main component symbol description] 100: hydraulic tensioning device 201126081 102a: first recessed portion 204: bottom surface 102aa: bottom surface 205: side surface 102ab: side surface 206: third recessed portion 104: piston 208: fourth recessed portion 104a : bottom surface 210 : second through hole 104 b : second recess portion 212 : channel portion 104ba : bottom surface 214 : projection portion 104bb : side surface 300 : air valve 104 c : top surface 302 : top surface 104 d : first through hole 304 : bottom surface 108: elastic member 400: air valve 110: check valve 402: top surface 112: hydraulic passage 500: air valve 200: air valve 502: top surface 202: top surface 504: bottom surface
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