A7 542876 ___B7_ 五、發明說明（>) 次壓力口 28之壓力就會下降。藉此’閥芯51會收斂至二 次壓力口 28之壓力所造成之推力和第2彈簧54之推力兩 者平衡的位置上，而二次壓力口 28之壓力（二次壓力)即爲 對應於第2彈簧54之縮短量(操作桿44之操作量)之壓力 ，亦即二次壓力。 【發明欲解決之課題】 有上述構造之減壓閥上’由於二次壓力而在閥芯51上 產生一端側方向之推力，此推力透過第2彈簧54把活塞 152往上推，並以反作用力傳向操作桿44。因此，操作桿 44之操作力會隨著二次壓力之上昇而增大。 上述推力因和閥芯51之受壓面積成正比，在爲求大流 量化而使閥芯51大型化時，操作力會過大而導致操作上之 障礙。 爲避免上述推力所造成之操作力增加之問題，相關技 術有如日本專利特公平03-50126上所記載者。此爲第2習 知形態。此技術係如第5圖所示，第2活塞58把固接於下 端之閥桿59以下垂狀態保持在第1活塞152(相當於第1習 知形態之活塞52)之下端；該第2活塞58，係在閥芯151( 相當於第1習知形態之閥芯51)嵌裝成可相對滑動，用來 藉著向上作用而產生與在閥芯151所發生之一端側方向之 推力相平衡之他端側方向之推力。因在第2活塞58所發生 之另一端側方向之推力作用於第1活塞152，故透過第2 彈簧54而傳達的一端側方向之推力會被抵消。因此，操作 桿44之操作力隨著二次壓力之上昇而增加之現象會消失。 ____5___ _一 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） —I----------------訂·--------1AWI (請先閱讀背面之注意事項再填寫本頁) 542876 A7 B7 五、發明說明（j) 然而，這種減壓閥無法使閥芯151增加控制流量。這 是因爲閥桿59軸向貫穿閥芯151，而使軸向流過第一次虜 力口 49、二次壓力口 28、及排洩口 26之間之通路面積縮 小了（相當於閥桿59之截面積）。 本發明係著眼於上述習知的問題點而開發出來。 亦即本發明之目的爲提供一種減壓閥，其爲避免二次 壓力所產生之一方向推力使操作桿的操作力增加而造成操 作上之阻礙，故產生與二次壓力相當之另一方向的推力’ 使兩方向之推力大致相互抵消，而且相較於無上述構成之 習知減壓閥，也不會有控制流量降低等問題發生。 【解決課題之手段及作用效果】 爲達成上述目的，本發明，係具有閥芯，該閥芯承受 二次壓力之同時，透過活塞在抵抗該二次壓力之方向上承 受來自外部之推力，而在閥座內之孔內移動；閥芯移動量 所對應之二次壓力由一次壓力減壓產生且其輸出値可調整 ，其特徵在於： 前述二次壓力中有部分係利用閥芯及活塞來承受，並 且經由設於閥座內之油路(由二次壓力側連通到活塞)來承 受。 又，前述二次壓力中有部分係利用閥芯及設於活塞之 受壓部來承受，並且經由設於閥座內之油路（由二次壓力側 連通到活塞)來承受，而且 將內嵌有活塞之套筒以可拆裝之方式設於閥座內，並 且將油路連接在活塞及套筒之間。 6 — 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） --------訂---------線. C請先閱讀背面I注意事項存填寫本頁) 542876 A7 B7 五 、發明說明（/^ ) 根據上述構成，因二次壓力作用於活塞上而產生一方 向推力，故二次壓力作用於閥芯上而產生之另一方向之推 力會被抵消，讓閥芯移動的推力降低，而使操作性提高。 而且不致降低控制流量。 又，若如上述一樣在活塞與拆裝自如的套筒之間連接 油路，藉由活塞與套筒之更換，可改變承受二次壓力的面 積，並能自由地選定抵消另一方向推力的比例。因此，機 器之汎用性會提高。 【發明之實施形態】 以下，參照圖式詳細說明本發明之實施形態。又，即 ί吏ill示形狀和習知形態不同，但在構成上無差異的要素上 均附上相同符號。 首先，將第1實施形態之減壓閥顯示於第1圖。 閥本體40係具有閥座41，該閥座具備一次壓力口 49 、一次壓力口 28、及排洩口 26 ; —次壓力口 49係連接在 油壓栗等油壓源23上，排洩口 26則連接在槽24上。 在閥本體40之一端側安裝有搖動自如之操作桿44。 閥本體40，係在閥座41內具備閥芯51，該閥芯51 用來將〜次壓力口 49、二次壓力口 28、及排洩口 26之間 予以連通/遮斷；並且具備活塞52，該活塞52滑動自如地 插入閥芯51內，用來讓閥芯51朝一端側方向與另一端側 。活塞52係利用受本身另一端側之彈簧座12所 支撐之第1彈簧53而被往上推而往一端側。因此，活塞 52 用本身一端上之抵接部11來抵接於固定在操作桿 -------------鼋i — (請先閱讀背面之注意事項再填寫本頁) 訂---------線·A7 542876 ___B7_ 5. Explanation of the invention (>) The pressure at the secondary pressure port 28 will drop. In this way, the valve core 51 will converge to a position where the thrust caused by the pressure of the secondary pressure port 28 and the thrust of the second spring 54 are balanced, and the pressure (secondary pressure) of the secondary pressure port 28 is corresponding. The secondary pressure is the pressure of the shortened amount of the second spring 54 (the operation amount of the operation lever 44). [Problems to be Solved by the Invention] On the pressure reducing valve having the above-mentioned structure, a thrust force in one end side direction is generated on the valve core 51 due to the secondary pressure, and this thrust force pushes the piston 152 upward through the second spring 54 and reacts with the reaction The force is transmitted to the operating lever 44. Therefore, the operating force of the operating lever 44 increases as the secondary pressure increases. The above-mentioned thrust force is proportional to the pressure area of the valve element 51. When the valve element 51 is enlarged in order to quantify the large flow, the operating force will be too large, which will cause an obstacle to operation. In order to avoid the problem of increased operating force caused by the above thrust, the related technology is as described in Japanese Patent Unexamined Publication No. 03-50126. This is the second known form. This technology is shown in FIG. 5. The second piston 58 keeps the valve rod 59 fixed to the lower end in a drooping state below the first piston 152 (equivalent to the piston 52 of the first known form); the second piston 58 The piston 58 is fitted on the valve element 151 (equivalent to the valve element 51 of the first known form) so as to be relatively slidable, and is used to generate a thrust force in the direction of one end side of the valve element 151 by acting upward. Balance the thrust from the other side. Since the thrust in the other end side direction generated by the second piston 58 acts on the first piston 152, the thrust in the one end side direction transmitted through the second spring 54 is canceled. Therefore, the phenomenon that the operating force of the operating lever 44 increases as the secondary pressure increases disappears. ____5___ _A paper size is applicable to China National Standard (CNS) A4 (210 X 297 mm) —I ---------------- Order · -------- 1AWI (Please read the precautions on the back before filling this page) 542876 A7 B7 V. Description of the invention (j) However, this pressure reducing valve cannot increase the control flow of the spool 151. This is because the valve rod 59 penetrates the spool 151 in the axial direction, so that the area of the passage between the first pressure port 49, the second pressure port 28, and the drain port 26 flowing in the axial direction is reduced (equivalent to the valve rod 59 Section area). The present invention has been developed focusing on the conventional problems. That is, the object of the present invention is to provide a pressure reducing valve, in order to avoid the operation force of the operating lever being increased due to the thrust in one direction caused by the secondary pressure, and the other direction equivalent to the secondary pressure is generated. Thrust force 'causes the thrust forces in both directions to substantially cancel each other, and compared with the conventional pressure reducing valve without the above-mentioned structure, problems such as reduced control flow rate do not occur. [Means for solving problems and effects] In order to achieve the above-mentioned object, the present invention has a valve core that receives a secondary pressure and at the same time receives a thrust from the outside through a piston in a direction resisting the secondary pressure, and Move in the hole in the valve seat; the secondary pressure corresponding to the valve core movement amount is generated by the primary pressure decompression and its output can be adjusted. It is characterized in that part of the aforementioned secondary pressure uses the valve core and the piston to It bears, and bears through the oil path (connected to the piston from the secondary pressure side) in the valve seat. In addition, part of the secondary pressure is received by the valve core and the pressure receiving portion provided in the piston, and is received by an oil path (connected from the secondary pressure side to the piston) provided in the valve seat. The sleeve in which the piston is embedded is detachably provided in the valve seat, and the oil circuit is connected between the piston and the sleeve. 6 — This paper size applies Chinese National Standard (CNS) A4 specification (210 X 297 mm) -------- Order --------- Line. C Please read the precautions on the back I (Fill in this page) 542876 A7 B7 V. Description of the invention (/ ^) According to the above structure, the secondary pressure acts on the piston to generate thrust in one direction, so the secondary pressure acts on the spool in the other direction. It will be canceled, and the thrust to move the spool will be reduced, which will improve the operability. And does not reduce the control flow. In addition, if the oil path is connected between the piston and the detachable sleeve as described above, by replacing the piston and the sleeve, the area under the secondary pressure can be changed, and the one that can offset the thrust in the other direction can be freely selected. proportion. Therefore, the versatility of the machine will be improved. [Embodiment of the invention] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In other words, the ill shows that the shape and the known form are different, but the elements that have no difference in structure are all attached with the same symbol. First, the pressure reducing valve of the first embodiment is shown in FIG. 1. The valve body 40 has a valve seat 41, which has a primary pressure port 49, a primary pressure port 28, and a drain port 26; the secondary pressure port 49 is connected to a hydraulic pressure source 23 such as a hydraulic pump, and the drain port 26 is Connected to the slot 24. A swingable operating lever 44 is attached to one end of the valve body 40. The valve body 40 is provided with a valve element 51 in the valve seat 41. The valve element 51 is used to communicate / block between the secondary pressure port 49, the secondary pressure port 28, and the drain port 26; and the piston 52 is provided. The piston 52 is slidably inserted into the valve core 51 and is used to make the valve core 51 toward one end side and the other end side. The piston 52 is pushed upward to one end side by a first spring 53 supported by a spring seat 12 on the other end side. Therefore, the piston 52 uses the contact portion 11 on one end of the piston 52 to abut on the operation lever fixed ------------- 鼋 i — (Please read the precautions on the back before filling in this page) Order --------- line ·
X 297公釐） 542876 A7 _B7____ 五、發明說明（(） 44上之連桿57。閥芯51係自彈簧座12朝另一端側下垂， 並且被受彈簧座12所支撐之第2彈簧54施加往另一端側 方向之彈壓。 在此，彈簧座12之直徑比抵接部11之直徑爲大，而 在彈簧座12與抵接部11之間形成段差部13。 閥座41係具有受壓室14，對段差部13施加油壓而產 生另一端側方向之推力；及油路15，把二次壓力口 28之 壓力導入受壓室14。 其次說明減壓閥之動作。操作桿44在中立位置時二次 壓力口 28呈現一液壓油停止供應狀態。亦即，閥芯51係 保持在被第2彈簧54往下推後的位置上，在此位置二次壓 力口 28和一次壓力口 49之間係遮斷狀態，而二次壓力口 28和排洩口 26之間則呈連通狀態。 當把操作桿44由中立位置操作至箭頭a方向而成爲運 轉位置時，活塞52即被連桿57往下推，而閥芯51則透過 第2彈簧54被往下推而呈液壓油供應狀態。亦即在此位置 ，二次壓力口 28和一次壓力口 49之間呈連通狀態，而在 二次壓力口 28與排洩口 26之間則呈遮斷狀態，二次壓力 口 28之壓力會上昇並藉由二次壓力口 28供應液壓油。/ 此時，二次壓力口 28之壓力會抵抗第2彈簧54而欲 把閥芯51往上推。閥芯51 —被往上推二次壓力口 28的壓 力隨即下降。藉此，閥芯51將收斂於二次壓力口 28的壓 力所造成之推力和第2彈簧54之推力彼此平衡之位置上， 故二次壓力口 28的壓力爲一與第2彈簧54之縮短量(操作 _____ 8_ 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） ---------------------訂·----------11--- (請先閱讀背面之注意事項再填寫本頁) 542876 A7 ____B7 ___ 五、發明說明（L ) 桿44之操作量)相對應之壓力’亦即二次壓力。 此時，由於二次壓力在閥芯51上會產生一端側方向之 推力，該推力透過第2彈簧54把活塞52往上推，但二次 壓力同時透過油路15被導入受壓室14，並作用於段差部 13而產生另一端側方向之推力’將活塞52往下推。 因此，可抵消由於在閥芯51產生之一端側方向之推力 對操作桿操作力所造成之增加部分。 根據上述第1實施形態，由於在閥芯51產生之一端側 方向之推力對操作桿操作力所造成之增加部分被抵消掉’ 故本發明之操作性比第1習知形態爲高。 而且，因不必如第2習知形態一樣設置貫穿閥芯內的 • 構件，故與第1習知形態相較，不會有大型化和控制流量 降低等之缺點。 其次說明第2實施形態。和第1實施形態之差異係將 在與活塞之間形成有受壓室之閥座部分，做成對於閥座拆 裝自如的套筒。藉著把此套筒和活塞成套更換，能改變受 壓室另一端側方向之受壓面積，而可自由地選定抵消掉操 作桿操作力增加部分之比例。 第2圖顯示第2實施形態之減壓閥，第3圖顯示第2 圖之放大詳細圖。和第1實施形態相同之構件均賦予相同 的符號，並省略其說明。 閥本體90係於閥座91內具備閥芯51，並具備使閥芯 51移動之活塞92。活塞92係被滑動自如地插入以可拆裝 方式被嵌入閥座91內之套筒80內。活塞92之一端側上具 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） - * 螓 ---I----I I---------I 訂 * - -------—ΑνΊ (請先閱讀背面之注意事項再填寫本頁) 542876 B7 五、發明說明（1 ^ 備彈簧座62，活塞92被支撐於彈簧座62之第1彈簧53 往上推。結果，活塞92會在抵接部61(位於活塞92之一 端側)抵接於固定於操作桿44上之連桿57。閥芯51係自 彈簧座62朝另一端側下垂，並藉由支撐在彈簧座62上之 第2彈簧54被施加一往另一端側方向之彈壓。 在此，活塞92在彈簧座62之外徑側之一端側具有小 徑部93，而在另一端側具有大徑部94。套筒80係在內徑 側之另一端側具有大徑部82，而在一端側具有小徑部81。 活塞92之小徑部93和套筒80之小徑部81上其直徑均大 致相等並以略靠緊的狀態滑動，而彈簧座62之大徑部94 和套筒80之大徑部82上其直徑均大致相等並以略靠緊狀 態滑動。 而且，在彈簧座62之小徑部9#套筒80之大徑部 82之間形成受壓室64。受壓室64係具備導入二次壓力之 油路65。導入受壓室64之二次壓力會對於在彈簧座62之 小徑部93和大徑部94之間所形成之段差部63加以作用而 產生另一端側方向之推力。 當將操作桿44從中立位置操作至箭頭a方向而成爲運 轉位置時’活塞92及閥芯51郎被往下推而使二次壓力口 之壓力上昇。此二次壓力係作用於閥芯51上，欲將活塞 92朝一端側方向往上推。但二次壓力則同時透過油路65 被導入受壓室64，並作用於段差部63而產生另一端側方 向之推力，將活塞92往下推。 因此’在閥芯51上產生之一端側方向之推力所造成之 — _____1〇_- 本纸張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） -------------暾·II (請先閱讀背面之注意事項再填寫本頁) 訂----：-----線. 542876 A7 ___B7___ 五、發明說明) 操作桿操作力增加部分會被抵消而提高操作性。、 在此，被抵消掉之操作桿操作力部分係與段差部之受 壓面積成正比。亦即，假設彈簧座62之小徑部91之直徑 爲dl，而大徑部94之直徑爲d2，則受壓面積爲(d2xd2-dlxdl)X 7Γ/4，而被抵消掉之操作桿操作力部分則和 (d2xd2-dlxdl)成正比。 根據第2實施形態，除了有第1實施形態之效果外， 還有，藉著將套筒80和活塞92成套地更換，即可改變dl 及/或d2。 當把活塞92更換爲dl及/或d2値爲相異時，套筒80 或活塞92均須成套地更換以維持大致緊靠狀態。 當將活塞92和套筒80成套更換而改變dl及/或d2時 ，就會改變受壓面積。於是會改變在活塞92發生之另一端 側方向之推力，故可自由地選定抵消掉操作桿操作力增加 部分之比例。 一般，操作桿操作力之最佳要求値係隨操作人員之習 慣、操作頻度、操作桿長度、及其他諸項條件之不同而不 同。因此，因上述構造可自由地選定抵消掉操作桿操作力 增加部分之比例，故對閥本體不須大幅地加以改變即可對 應不同的要求値。亦即，機器之泛用性會提高。 還有，本發明之減壓閥未必靠搖動自如的操作桿來操 作。也可以例如以將活塞在直線方向推入之方式來操作。 按照以上實施形態所述，根據本發明之減壓閥，二次 壓力作用後產生的推力所造成之操作力增加部分會被抵消 _L3_ 一 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐） —I--------A__w^--------訂--------- <請先閱讀背面之注意事項再填寫本頁) A7 542876 _B7_ 五、發明說明) 而使操作性提高。而且不降低控制流量下即可提高操作性 Ο 【圖式之簡單說明】 第1圖，係本發明第1實施形態之減壓閥。 第2圖，係本發明第2實施形態之減壓閥。 第3圖，係第2圖之詳細圖。 第4圖，係第1習知形態之減壓閥。 第5圖，係第2習知形態之減壓閥。 【符號說明】 15,65 油路 28 二次壓力口 41.91 閥座 51，151 閥芯 52.92 活塞 63 段差部 80 套筒 n n n n n n n n n in —ai n « ·1 11 n 1 Ha l_i n ^ ^ · fftBi an nfl ·ϋ —Bi m 1_1 I (請先閱讀背面之注意事項再填寫本頁) 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐）X 297 mm) 542876 A7 _B7____ 5. Description of the invention (() 44 of the connecting rod 57. The valve core 51 is suspended from the spring seat 12 to the other end side, and is applied by the second spring 54 supported by the spring seat 12 The spring is pushed toward the other end side. Here, the diameter of the spring seat 12 is larger than the diameter of the abutting portion 11, and a step portion 13 is formed between the spring seat 12 and the abutting portion 11. The valve seat 41 is under pressure. The chamber 14 applies oil pressure to the step portion 13 to generate thrust in the other end side direction; and the oil passage 15 introduces the pressure of the secondary pressure port 28 into the pressure receiving chamber 14. Next, the operation of the pressure reducing valve will be described. The operating lever 44 is at In the neutral position, the secondary pressure port 28 assumes a state where the supply of hydraulic oil is stopped. That is, the spool 51 is held in a position pushed down by the second spring 54. At this position, the secondary pressure port 28 and the primary pressure port 49 is in a blocked state, and the secondary pressure port 28 and the drain port 26 are in a communication state. When the operating lever 44 is operated from the neutral position to the direction of the arrow a to become the operating position, the piston 52 is connected by the connecting rod. 57 is pushed down, and the spool 51 is pushed down through the second spring 54 to present Pressure oil supply state. That is, at this position, the secondary pressure port 28 and the primary pressure port 49 are in a communication state, and the secondary pressure port 28 and the drain port 26 are in a blocked state. The secondary pressure port The pressure of 28 will rise and the hydraulic oil will be supplied through the secondary pressure port 28. / At this time, the pressure of the secondary pressure port 28 will resist the second spring 54 and push the spool 51 upward. The pressure of the push-up secondary pressure port 28 then drops. As a result, the valve core 51 will converge to a position where the thrust caused by the pressure of the secondary pressure port 28 and the thrust of the second spring 54 are balanced with each other, so the secondary pressure port The pressure of 28 is the shortening amount of the first and second spring 54 (operation _____ 8_ This paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) ------------- -------- Order · ---------- 11 --- (Please read the precautions on the back before filling this page) 542876 A7 ____B7 ___ V. Description of the Invention (L) Rod 44 The pressure corresponding to the operation amount) is the secondary pressure. At this time, due to the secondary pressure, a thrust force in the direction of one end side is generated on the spool 51, and the thrust force passes through the second spring 54 The piston 52 is pushed upward, but the secondary pressure is simultaneously introduced into the pressure receiving chamber 14 through the oil passage 15 and acts on the step portion 13 to generate a thrust force in the other end side direction 'to push the piston 52 downward. Therefore, it can be offset by Increasing part of the thrust force generated by one end side direction of the valve element 51 to the operating force of the operating lever. According to the above-mentioned first embodiment, the increase of thrust force produced by one end side direction of the valve element 51 is caused by the operating force of the operating lever. Partially cancelled out 'Therefore, the operability of the present invention is higher than the first conventional form. In addition, since it is not necessary to provide a member penetrating into the spool as in the second known form, compared with the first known form, there are no disadvantages such as increased size and reduced control flow. Next, a second embodiment will be described. The difference from the first embodiment is that a valve seat portion in which a pressure receiving chamber is formed between the piston and the piston is formed into a sleeve which is detachable from the valve seat. By replacing the sleeve and the piston as a set, the pressure area in the direction of the other end of the pressure chamber can be changed, and the proportion of the increase in the operating force of the operating lever can be freely selected. Fig. 2 shows the pressure reducing valve of the second embodiment, and Fig. 3 shows an enlarged detailed view of the second figure. The same members as those in the first embodiment are assigned the same reference numerals, and descriptions thereof are omitted. The valve body 90 includes a valve body 51 in a valve seat 91 and a piston 92 for moving the valve body 51. The piston 92 is slidably inserted into a sleeve 80 which is detachably inserted into the valve seat 91. One end of the piston 92 has the paper size applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 mm)-* 螓 --- I ---- I I --------- I Order *--------— ΑνΊ (Please read the precautions on the back before filling out this page) 542876 B7 V. Description of the invention (1 ^ Prepare spring seat 62, piston 92 is supported by the first spring of spring seat 62 53 pushes upward. As a result, the piston 92 will abut against the connecting rod 57 fixed on the operating rod 44 at the abutting portion 61 (located on one end side of the piston 92). The valve core 51 hangs from the spring seat 62 toward the other end side And a second spring 54 supported on the spring seat 62 is urged in the direction of the other end side. Here, the piston 92 has a small diameter portion 93 on one end side of the outer diameter side of the spring seat 62, and The other end side has a large diameter portion 94. The sleeve 80 has a large diameter portion 82 on the other end side of the inner diameter side and a small diameter portion 81 on one end side. The small diameter portion 93 of the piston 92 and the smaller portion of the sleeve 80 The diameter portions 81 are substantially equal in diameter and slide in a slightly tight state, while the large diameter portion 94 of the spring seat 62 and the large diameter portion 82 of the sleeve 80 are approximately equal in diameter and slide in a slightly tight state Further, a pressure receiving chamber 64 is formed between the small diameter portion 9 # of the spring seat 62 and the large diameter portion 82 of the sleeve 80. The pressure receiving chamber 64 is provided with an oil passage 65 for introducing a secondary pressure. The pressure receiving chamber 64bis The secondary pressure acts on the stepped portion 63 formed between the small-diameter portion 93 and the large-diameter portion 94 of the spring seat 62 to generate the thrust in the other end side direction. When the operating lever 44 is operated from the neutral position to the direction of arrow a When it is in the operating position, the piston 92 and the valve core 51 are pushed down to increase the pressure of the secondary pressure port. This secondary pressure is applied to the valve core 51, and the piston 92 is pushed upward toward one end side. However, the secondary pressure is simultaneously introduced into the pressure receiving chamber 64 through the oil passage 65, and acts on the step portion 63 to generate a thrust in the other end side direction, pushing the piston 92 downward. Therefore, one end is generated on the valve core 51 Caused by the thrust in the side direction — _____ 1〇_- This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) ------------- 暾 · II (Please Read the precautions on the back before filling out this page) Order ----: ----- line. 542876 A7 ___B7___ 5. Description of the invention The increase in operating force will be offset to improve operability. Here, the part of the operating force of the canceled lever is proportional to the pressure area of the stepped part. That is, assuming that the diameter of the small-diameter portion 91 of the spring seat 62 is dl and the diameter of the large-diameter portion 94 is d2, the pressure area is (d2xd2-dlxdl) X 7Γ / 4, and the canceled lever operation The force component is proportional to (d2xd2-dlxdl). According to the second embodiment, in addition to the effects of the first embodiment, it is also possible to change dl and / or d2 by replacing the sleeve 80 and the piston 92 as a set. When the piston 92 is replaced with dl and / or d2, the sleeve 80 or the piston 92 must be replaced in sets to maintain a substantially close state. When the piston 92 and the sleeve 80 are replaced in sets and the dl and / or d2 are changed, the pressure area is changed. As a result, the thrust in the direction of the other end side of the piston 92 is changed, so that the ratio that cancels out the increase in the operating force of the operating lever can be freely selected. In general, the best requirements for operating force of the joystick are different according to the habits of the operator, the frequency of operation, the length of the joystick, and other various conditions. Therefore, because the above structure can freely select the proportion that offsets the increase in the operating force of the operating lever, the valve body can be responded to different requirements without requiring substantial changes. That is, the versatility of the machine will increase. In addition, the pressure reducing valve of the present invention is not necessarily operated by a rocking operation lever. It may be operated, for example, by pushing the piston in a straight direction. According to the above embodiment, according to the pressure reducing valve of the present invention, the increase of the operating force caused by the thrust generated after the secondary pressure is applied will be offset _L3_ A paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) —I -------- A__w ^ -------- Order --------- < Please read the notes on the back before filling this page) A7 542876 _B7_ V. Description of the invention) to improve operability. In addition, the operability can be improved without reducing the control flow rate. [Simple illustration of the drawing] Fig. 1 is a pressure reducing valve according to the first embodiment of the present invention. Fig. 2 is a pressure reducing valve according to a second embodiment of the present invention. Figure 3 is a detailed view of Figure 2. Fig. 4 is a pressure reducing valve of the first known form. Fig. 5 is a pressure reducing valve of a second conventional form. [Symbol description] 15, 65 oil circuit 28 secondary pressure port 41.91 valve seat 51, 151 spool 52.92 piston 63 step difference 80 sleeve nnnnnnnnn in —ai n «· 1 11 n 1 Ha l_i n ^ ^ · fftBi an nfl · Ϋ —Bi m 1_1 I (Please read the notes on the back before filling out this page) This paper size applies to China National Standard (CNS) A4 (210 X 297 mm)