JPH0663882U - Hydraulic pump - Google Patents

Abstract

(57)【要約】 【目的】 外歯歯車２の位置が、外歯歯車２の両側面の
うちで、途中に絞り部がなく作用室１０からの流体の漏
れが多い蓋部材８の摺接面８ａに常に近づくようにし
て、外歯歯車２の側面からの漏れを減少させ、容積効率
を向上させる。 【構成】 蓋部材８の摺接面８ａに凹部（面取り部）８
ｂを形成して、蓋部材８の摺接面８ａ側の受圧面積を小
さくすることで、蓋部材８の摺接面８ａから外歯歯車２
に加わる作用力を減少させた。 (57) [Abstract] [Purpose] The position of the external gear 2 is the sliding contact of the lid member 8 on both side surfaces of the external gear 2 which does not have a throttle part in the middle thereof and in which a large amount of fluid leaks from the working chamber 10. By constantly approaching the surface 8a, leakage from the side surface of the external gear 2 is reduced and the volumetric efficiency is improved. [Structure] A recessed portion (chamfered portion) 8 is formed in a sliding contact surface 8a of a lid member 8.
By forming b to reduce the pressure-receiving area of the lid member 8 on the side of the sliding contact surface 8a, the external gear 2 is removed from the sliding contact surface 8a of the lid member 8.
The acting force applied to is reduced.

Description

【考案の詳細な説明】[Detailed description of the device]

【０００１】[0001]

【産業上の利用分野】[Industrial applications]

本考案は、偏心して内接噛合する外歯歯車と内歯歯車を回転させて作動流体を 吐出する液圧ポンプに関するものである。 The present invention relates to a hydraulic pump that discharges a working fluid by rotating an externally toothed gear and an internally toothed gear that are eccentrically and internally meshed.

【０００２】[0002]

【従来の技術】[Prior art]

従来の液圧ポンプは、特開平３−２３７２８１号公報にあるように、ポンプ本 体の側面に開口した収装孔に、外歯歯車と内歯歯車の回転自在に収納し、この収 装孔を閉塞する蓋部材を取り付けて、外歯歯車と内歯歯車の一方の側面にポンプ 本体の壁面が摺接し、他方の側面に蓋部材の壁面が摺接するように形成して、ポ ンプ本体と蓋部材の摺接面、及び両歯車で区画される作用室に、流体が吸入ポー トより吸入され、ポンプ作用がなされた後に吐出ポートより吐出される。 A conventional hydraulic pump, as disclosed in Japanese Patent Laid-Open No. 3-237281, accommodates an external gear and an internal gear rotatably in a storage hole opened on a side surface of the pump body. Install a lid member to close the pump, and form one wall of the external gear and the internal gear so that the wall surface of the pump body is in sliding contact with the other side surface and the wall surface of the lid member is in sliding contact with the other side surface. The fluid is sucked into the sliding contact surface of the lid member and the working chamber defined by the two gears from the suction port, and after being pumped, discharged from the discharge port.

【０００３】[0003]

【考案が解決しようとする課題】[Problems to be solved by the device]

最近、液圧ポンプの吐出量を大きくすることを検討しているが、それに伴い容 積効率を向上させることが重要となっている。作用室の高圧の流体が、外歯歯車 の両側面の隙間を介して回転軸の方向へ漏れる漏れ量について考えると、図４に 示すような外歯歯車１０２がポンプ本体１０３側の摺接面１０４に近づいた位置 （Ｘ位置とする）では、蓋部材１０５の摺接面１０６と外歯歯車１０２の隙間が 大きくなり、その隙間から作用室１０１の流体が容易に漏れて、漏れ量が多くな る。 Recently, we are considering increasing the discharge rate of a hydraulic pump, but it is important to improve the storage efficiency accordingly. Considering the amount of leakage of the high-pressure fluid in the working chamber in the direction of the rotating shaft through the gaps on both sides of the external gear, the external gear 102 as shown in FIG. At a position close to 104 (X position), the gap between the sliding contact surface 106 of the lid member 105 and the external gear 102 becomes large, and the fluid in the working chamber 101 easily leaks from the gap, resulting in a large leak amount. Become.

【０００４】 それに対して、図５に示すような外歯歯車１０２が蓋部材１０５の摺接面１０ ６に近づいた位置（Ｙ位置とする）では、蓋部材１０５の摺接面１０６と外歯歯 車１０２の隙間が小さくなり、そこからの流体の漏れ量が少なくなる。またポン プ本体１０３の摺接面１０４と外歯歯車１０２の間の隙間は大きくなるが、その 隙間の途中に外歯歯車１０２をポンプ本体１０３に対して回転支持するジャーナ ル部１０７の小さな隙間が位置しているので、ポンプ本体１０３の摺接面１０４ 側からも作用室１０１の流体が漏れにくく、全体の漏れ量が少ない。On the other hand, when the external gear 102 shown in FIG. 5 is close to the sliding contact surface 106 of the lid member 105 (Y position), the sliding contact surface 106 of the lid member 105 and the external teeth The gap between the toothed wheels 102 becomes smaller, and the amount of fluid leaking from the gap becomes smaller. Also, the gap between the sliding contact surface 104 of the pump body 103 and the external gear 102 becomes large, but a small gap in the journal portion 107 that rotatably supports the external gear 102 with respect to the pump body 103 in the middle of the gap. Is located, the fluid in the working chamber 101 does not easily leak from the sliding contact surface 104 side of the pump body 103, and the total amount of leakage is small.

【０００５】 そのため、液圧ポンプの吐出量は、図６に示すように、外歯歯車１０２が蓋部 材１０５の摺接面１０６に近づいたＹ位置の方が多くなる。つまり容積効率を向 上させるためには、外歯歯車を蓋部材の摺接面に近づけた位置にすればよいこと になる。 しかしながら、外歯歯車１０２の両側面に流体によって作用する圧力の分布は 、図７に示すように、ポンプ本体１０３側は受圧面積は小さいが、ジャーナル部 １０７の小さな隙間のため圧力は高く保持され台形状に分布している。また蓋部 材１０５側は受圧面積は大きいが、圧力は三角形状に分布している。そして、両 面の力はほぼつり合っていて、外歯歯車１０２は、両摺接面１０４、１０６とは ほぼ同じ距離の間隔の位置になり、加工精度等の影響で、もし外歯歯車１０２が ポンプ本体１０３の摺接面１０４に近づいたＸ位置になると容積効率が低下して しまう。Therefore, as shown in FIG. 6, the discharge amount of the hydraulic pump is larger at the Y position where the external gear 102 is closer to the sliding contact surface 106 of the lid member 105. In other words, in order to improve the volumetric efficiency, it suffices to position the external gear close to the sliding contact surface of the lid member. However, as shown in FIG. 7, the distribution of the pressure applied by the fluid on both sides of the external gear 102 is such that the pressure receiving area is small on the pump body 103 side, but the pressure is kept high due to the small gap in the journal portion 107. It is distributed in a trapezoidal shape. The pressure receiving area is large on the lid member 105 side, but the pressure is distributed in a triangular shape. The forces on both surfaces are almost balanced, and the external gear 102 is positioned at the same distance as the sliding contact surfaces 104 and 106, and if the external gear 102 is affected by machining accuracy and the like. When becomes the X position near the sliding contact surface 104 of the pump body 103, the volumetric efficiency decreases.

【０００６】[0006]

【課題を解決するための手段】[Means for Solving the Problems]

本考案は上述した問題を解決するためになされたもので、ポンプ本体の側面に 開口する収装孔内に、この収装孔の底部に位置する軸受部で前記ポンプ本体に対 して回転可能に軸支された外歯歯車と、この外歯歯車に対して偏心して内接噛合 した内歯歯車を回転自在に収納し、前記収装孔の側面に蓋部材を取り付けて前記 収装孔を閉塞して、前記両歯車を前記収装孔及び前記蓋部材の摺接面に摺接させ 、前記両歯車で区画される作用室へ吸入ポートより流体を吸入するとともに、吐 出ポートより流体を吐出する液圧ポンプにおいて、前記蓋部材の摺接面に、前記 蓋部材の摺接面から前記外歯歯車よ流体によって作用する力が前記収装孔の摺接 面から前記外歯歯車に流体によって作用する力より小さくなるように摺接面積を 小さくする凹部を形成したことを特徴とするものである。 The present invention has been made in order to solve the above-mentioned problems, and it is possible to rotate a pump body in a storage hole that is opened on a side surface of the pump body by a bearing portion located at the bottom of the storage hole. The external gear that is axially supported by the external gear and the internal gear that is eccentrically and internally meshed with the external gear are rotatably housed, and a lid member is attached to the side surface of the housing hole to secure the housing hole. When the gears are closed, the both gears are brought into sliding contact with the sliding contact surfaces of the storage hole and the lid member to suck the fluid into the working chamber defined by the both gears from the suction port, and to suck the fluid from the discharge port. In the discharging hydraulic pump, a force acting on the sliding contact surface of the lid member by the fluid from the sliding contact surface of the lid member causes a fluid to flow to the external gear from the sliding contact surface of the storage hole. The recess that reduces the sliding contact area so that it is smaller than the force acting by Is characterized in that the formed.

【０００７】[0007]

【作用】[Action]

蓋部材と収装孔の摺接面のうち作用室の漏れが多い蓋部材の摺接面に、凹部を 形成したことにより、外歯歯車に対する蓋部材の摺接面の摺接面積が減少する。 これにより、蓋部材の摺接面側の流体の受圧面積が小さくなり、外歯歯車に作用 する力が小さくなる。すると、外歯歯車に作用する力は、常に収装孔の摺接面側 が大きくなり、外歯歯車は蓋部材の摺接面に近づいた位置になる。この位置では 、流体が作用室から外歯歯車の側面の隙間を経て回転軸方向へ漏れる漏れ量が少 ないので、容積効率が向上する。 By forming a recess on the sliding contact surface of the lid member and the storage hole where the action chamber leaks a lot, the sliding contact area of the sliding contact surface of the lid member with respect to the external gear is reduced. . As a result, the pressure receiving area of the fluid on the sliding contact surface side of the lid member is reduced, and the force acting on the external gear is reduced. Then, the force acting on the external gear always increases on the sliding contact surface side of the housing hole, and the external gear moves to a position closer to the sliding contact surface of the lid member. At this position, the amount of fluid that leaks from the working chamber through the gap on the side surface of the external gear in the direction of the rotation axis is small, so that the volumetric efficiency is improved.

【０００８】[0008]

【実施例】【Example】

以下本考案の実施例を図面に基づいて説明する。図１において、１は回転軸で あり、図示しない他の駆動源により回転駆動されている。この回転軸１には、外 歯歯車２が一体的に嵌合されており、回転軸１と共に回転するようになっている 。そして外歯歯車２には、外歯歯車２の歯数より１枚歯数の多い内歯歯車４が偏 心して内接噛合されている。 An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a rotary shaft, which is rotationally driven by another drive source (not shown). An external gear 2 is integrally fitted to the rotary shaft 1 so as to rotate together with the rotary shaft 1. An internal gear 4 having one more tooth than the external gear 2 is eccentrically meshed with the external gear 2.

【０００９】 図２に示すように、ポンプ本体６の側面６ａが窪まされて、この側面６ａに開 口する収装孔７がポンプ本体６に形成されている。この収装孔７内には、収装孔 ７の摺接面７ａの底部に位置した軸受部７ｂで回転方向に軸支された外歯歯車２ と、この外歯歯車２に対して偏心して内接噛合した内歯歯車４が回転自在に収装 されている。ポンプ本体６の側面６ａには、蓋部材８が合わされ、その外周に沿 って配置された複数のボルト９により取り付けられて、収装孔７を閉塞している 。そして、両歯車２，４は、収装孔７の摺接面７ａと蓋部材８の摺接面８ａの間 に挟まれ、両摺接面７ａ，８ａにそれぞれ小さい隙間を介して摺接している。さ らに、蓋部材８の摺接面８ａには、面取り部８ｂが形成され、外歯歯車２と摺接 面８ａとの間の摺接面積を小さくしている。As shown in FIG. 2, a side surface 6 a of the pump body 6 is recessed, and a housing hole 7 that opens to the side surface 6 a is formed in the pump body 6. In the storage hole 7, an external gear 2 axially supported in the rotational direction by a bearing portion 7b located at the bottom of the sliding contact surface 7a of the storage hole 7, and eccentric to the external gear 2. The internally toothed gear 4 that is internally meshed is rotatably accommodated. A lid member 8 is fitted to the side surface 6a of the pump body 6, and is attached by a plurality of bolts 9 arranged along the outer periphery thereof to close the storage hole 7. The two gears 2 and 4 are sandwiched between the sliding contact surface 7a of the housing hole 7 and the sliding contact surface 8a of the lid member 8 and are in sliding contact with the sliding contact surfaces 7a and 8a via a small gap. There is. Furthermore, a chamfered portion 8b is formed on the sliding contact surface 8a of the lid member 8 to reduce the sliding contact area between the external gear 2 and the sliding contact surface 8a.

【００１０】 また、回転軸１と共に外歯歯車２が回転駆動されたときに、外歯歯車２と内歯 歯車４との各歯及び両摺接面７ａ，８ａにより囲まれた複数の作用室１０が、回 転に伴って膨張と収縮を行い、歯車ポンプとしてポンプ作用をなすように形成さ れている。そして、作用室１０が膨張しつつある状態の時に、この作用室１０に 連通する吸入ポート１２，１４が、それぞれ収装孔７の摺接面７ａと蓋部材８の 摺接面８ａに、両歯車２，４に沿って円弧状に窪まされて形成されている。Further, when the external gear 2 is driven to rotate together with the rotary shaft 1, a plurality of action chambers surrounded by the respective teeth of the external gear 2 and the internal gear 4 and both sliding contact surfaces 7 a, 8 a. 10 expands and contracts as it rotates, and is formed as a gear pump. When the working chamber 10 is inflating, the suction ports 12 and 14 communicating with the working chamber 10 are connected to the sliding contact surface 7a of the storage hole 7 and the sliding contact surface 8a of the lid member 8, respectively. It is formed by being recessed in an arc shape along the gears 2 and 4.

【００１１】 さらに、作用室１０が膨張を開始する側の吸入ポート１２に連続して、吸入ポ ート１２より深い窪みからなる吸入室１５が形成されている。この吸入室１５に は、ポンプ本体６に形成された吸入口１６が接続されており、吸入口１６には、 図示しないタンクから作動流体が供給されるように接続されている。 一方、作用室１０が収縮しつつある状態の時に、この作用室１０に連通する吐 出ポート１８，２０が、それぞれ収装孔７の摺接面７ａと蓋部材８の摺接面８ａ に、両歯車２，４に沿って円弧状に窪まされて形成されている。また、作用室１ ０が収縮を終了する側の吐出ポート１８に連続して、吐出ポート１８より深い窪 みからなる吐出室２１が形成されている。この吐出室２１には、図示しない外部 の機器に作動流体を供給する吐出口２２が接続されている。Further, a suction chamber 15 having a recess deeper than the suction port 12 is formed continuously with the suction port 12 on the side where the working chamber 10 starts to expand. A suction port 16 formed in the pump body 6 is connected to the suction chamber 15, and the suction port 16 is connected so that the working fluid is supplied from a tank (not shown). On the other hand, when the working chamber 10 is contracting, the discharge ports 18 and 20 communicating with the working chamber 10 are provided on the sliding contact surface 7a of the storage hole 7 and the sliding contact surface 8a of the lid member 8, respectively. It is formed by being recessed in an arc shape along both gears 2, 4. Further, a discharge chamber 21 having a recess deeper than the discharge port 18 is formed continuously with the discharge port 18 on the side where the working chamber 10 ends contraction. A discharge port 22 that supplies a working fluid to an external device (not shown) is connected to the discharge chamber 21.

【００１２】 そして、吐出室２１に連接して連通孔２４が形成され、ポンプ本体６に収納さ れたスリーブ２６の摺動孔２８が連通孔２４が連通するように構成されている。 また、スリーブ２６を径方向に貫通する貫通孔２９ａが、摺動孔２８に接続する ように形成され、摺動孔２８と吸入室１５とを連通する逃し流路２９に貫通孔２ ９ａが接続している。A communication hole 24 is formed so as to be connected to the discharge chamber 21, and a sliding hole 28 of the sleeve 26 housed in the pump body 6 is configured to communicate with the communication hole 24. Further, a through hole 29a that penetrates the sleeve 26 in the radial direction is formed so as to be connected to the sliding hole 28, and the through hole 29a is connected to the escape passage 29 that connects the sliding hole 28 and the suction chamber 15. is doing.

【００１３】 スリーブ２６の摺動孔２８には、弁体３０が摺動自在に嵌合されており、ポン プ本体６に形成された収納孔３２に、プラグ３４がＯリング３６により漏れ止め されて螺入されている。また収納孔３２内の弁体３０とプラグ３４との間には、 ばね３８が配設されていて、ばね３８の付勢力で、逃し流路２９と吐出室２１間 を遮断する方向に付勢し、リリーフ弁３９を構成している。A valve body 30 is slidably fitted in a sliding hole 28 of the sleeve 26, and a plug 34 is leak-tightened by an O-ring 36 in a housing hole 32 formed in the pump body 6. Have been screwed in. Further, a spring 38 is arranged between the valve body 30 and the plug 34 in the storage hole 32, and is biased by the biasing force of the spring 38 in the direction of blocking the escape passage 29 from the discharge chamber 21. The relief valve 39.

【００１４】 前記ばね３８の付勢力に抗して弁体３０が摺動すると、弁体３０が貫通孔２９ ａを開口して、逃し流路２９、貫通孔２９ａ、摺動孔２８、連通孔２４を介して 、吸入室１５と吐出室２１を連通される。そして、逃し流路２９内には、その一 部が絞られる絞り部４２が形成され、この絞り部４２と収納孔３２を連通する圧 力導入路４４が形成されている。そして、絞り部４２を通過する作動流体に応じ て生じる圧力を、収納孔３２，摺動孔２８，弁体３０及びプラグ３４で構成され た背圧室４６に導くようにしている。When the valve body 30 slides against the biasing force of the spring 38, the valve body 30 opens the through hole 29 a, and the escape passage 29, the through hole 29 a, the sliding hole 28, the communication hole. The suction chamber 15 and the discharge chamber 21 are communicated with each other via 24. Further, in the escape passage 29, a throttle portion 42, a portion of which is narrowed, is formed, and a pressure introduction passage 44 that connects the throttle portion 42 and the storage hole 32 is formed. Then, the pressure generated according to the working fluid passing through the throttle portion 42 is guided to the back pressure chamber 46 constituted by the housing hole 32, the sliding hole 28, the valve body 30 and the plug 34.

【００１５】 次に、前述した液圧ポンプの作動について説明する。まず、回転軸１が図１の 矢印の方向に回転駆動されると、回転軸１の回転と共に外歯歯車２と内歯歯車４ が噛合した状態で回転して、外歯歯車２と内歯歯車４との各歯及び両摺接面７ａ ，８ａにより囲まれた作用室１０が、一回転の間に膨張と収縮をする。作用室１ ０が膨張するときに、作用室１０は吸入ポート１２，１４から作動流体を吸入し 、作用室１０が収縮するときに、作用室１０は吐出ポート１８，２０から加圧し た作動流体を吐出する。Next, the operation of the above-described hydraulic pump will be described. First, when the rotary shaft 1 is rotationally driven in the direction of the arrow in FIG. 1, the external gear 2 and the internal gear 4 rotate together with the rotation of the rotary shaft 1, and the external gear 2 and the internal gear 4 rotate. The working chamber 10 surrounded by the teeth of the gear 4 and the sliding contact surfaces 7a, 8a expands and contracts during one rotation. When the working chamber 10 expands, the working chamber 10 sucks the working fluid from the suction ports 12 and 14, and when the working chamber 10 contracts, the working chamber 10 pressurizes the working fluid from the discharge ports 18 and 20. Is discharged.

【００１６】 吐出ポート１８，２０から吐出された作動流体の圧力が、吐出室２１を介して 弁体３０に作用し、弁体３０をばね３８の付勢力に抗して摺動させる。弁体３０ が摺動すると、貫通孔２９ａが開口し、摺動孔２８、貫通孔２９ａを介して、吐 出室２１と逃し流路２９とを連通する。そして、吐出ポート１８，２０から吐出 された作動流体は、逃し流路２９から吸入室１５に排出される。このように、吐 出ポート１８，２０から吐出された作動流体の圧力は、ばね３８の付勢力に応じ た圧力に規制される。The pressure of the working fluid discharged from the discharge ports 18 and 20 acts on the valve body 30 via the discharge chamber 21 to slide the valve body 30 against the biasing force of the spring 38. When the valve body 30 slides, the through hole 29a opens, and the discharge chamber 21 and the escape passage 29 communicate with each other through the sliding hole 28 and the through hole 29a. Then, the working fluid discharged from the discharge ports 18 and 20 is discharged to the suction chamber 15 from the escape passage 29. In this way, the pressure of the working fluid discharged from the discharge ports 18 and 20 is regulated to the pressure corresponding to the biasing force of the spring 38.

【００１７】 また、収装孔７を閉塞する蓋部材８の外歯歯車２と摺接する側に、面取り部８ ｂが形成され、外歯歯車２と蓋部材８の摺接面積を減少させている。すると、外 歯歯車４の両側面に流体によって作用する圧力の分布は、図３に示すように、蓋 部材８の摺接面８ａ側は、摺接面積の減少に伴って圧力の受圧面積が減少し、こ の摺接面８ａ側から作用する圧力の分布は、従来の破線図示の状態から実線で図 示した状態になって、その作用力が小さくなる。それに対して、収装孔７の摺接 面７ａ側は、受圧面積は小さいが軸受部７ｂの小さな隙間のため圧力は高く保持 された台形形状に分布して、その作用力は従来と変わらない。そのため、両面に 作用する力の関係は、常に収装孔７の摺接面７ａ側の方が大きな作用力となり、 外歯歯車２の位置は、必ず蓋部材８の摺接面８ａに近づいた図５に示されるＹ位 置になる。Further, a chamfered portion 8 b is formed on the side of the lid member 8 that closes the housing hole 7 in sliding contact with the external gear 2, to reduce the sliding contact area between the external gear 2 and the lid member 8. There is. Then, as shown in FIG. 3, the distribution of the pressure applied by the fluid on both side surfaces of the external gear 4 is such that, as shown in FIG. 3, the sliding contact surface 8a side of the lid member 8 has a smaller pressure receiving area as the sliding contact area decreases. The distribution of the pressure acting from the sliding contact surface 8a side decreases from the state shown by the conventional broken line to the state shown by the solid line, and the acting force becomes small. On the other hand, the sliding contact surface 7a side of the storage hole 7 is distributed in a trapezoidal shape in which the pressure receiving area is small but the pressure is kept high due to the small gap of the bearing portion 7b, and the acting force is the same as before. . Therefore, regarding the relationship of the forces acting on both surfaces, the acting force is always larger on the sliding contact surface 7a side of the storage hole 7, and the position of the external gear 2 is always closer to the sliding contact surface 8a of the lid member 8. The Y position is shown in FIG.

【００１８】 ところで、図５に示すＹ位置は、蓋部材８の摺接面８ａと外歯歯車２の隙間が 小さくなって漏れ量が少なくなる。また、収装孔７の摺接面７ａと外歯歯車２の 間の隙間が大きくなるが、その隙間の通路の途中に外歯歯車２をポンプ本体６に 対して回転支持する軸受部７ｂの小さな隙間が位置しているので、収装孔７の摺 接面７ａ側からの作用室１０の流体は漏れにくく、全体の漏れ量が少ない。それ に対して、図４に示す外歯歯車２が収装孔７の摺接面７ａに近づいたＸ位置は、 蓋部材８の摺接面８ａと外歯歯車２の隙間から流体が抵抗なく漏れるので、漏れ 量が多くなる。このように、外歯歯車２が蓋部材８の摺接面８ａに近づいたＹ位 置の方が漏れ量を少なくなる。By the way, at the Y position shown in FIG. 5, the gap between the sliding contact surface 8a of the lid member 8 and the external gear 2 is reduced, and the amount of leakage is reduced. Further, although the gap between the sliding contact surface 7a of the housing hole 7 and the external gear 2 becomes large, the bearing portion 7b that rotatably supports the external gear 2 with respect to the pump body 6 is provided in the middle of the passage of the gap. Since a small gap is located, the fluid in the working chamber 10 from the sliding surface 7a side of the storage hole 7 is unlikely to leak, and the total leak amount is small. On the other hand, at the X position where the external gear 2 shown in FIG. 4 approaches the sliding contact surface 7a of the housing hole 7, the fluid does not flow from the gap between the sliding contact surface 8a of the lid member 8 and the external gear 2 without resistance. Since it leaks, the amount of leakage increases. Thus, the amount of leakage is smaller in the Y position where the external gear 2 is closer to the sliding contact surface 8a of the lid member 8.

【００１９】 このように、本実施例は、蓋部材８の摺接面８ａに、蓋部材８と外歯歯車２の 間の摺接面積を小さくする面取り部８ｂを形成した構成を有して、外歯歯車２と 蓋部材８の摺接面８ａが摺接する面積を小さくし、外歯歯車２には常に収装孔７ の摺接面７ａ側から流体による力が大きく加わるようにして、外歯歯車２の位置 が、必ず蓋部材８の摺接面８ａに近づいたＹ位置になるようにしたので、吐出ポ ート１８，２０側の作用室１０にて高圧となった流体が、外歯歯車２の両側の側 面の隙間から回転軸１方向に漏れる漏れ量を少なくすることができ、ポンプの容 積効率を向上させることができる。As described above, the present embodiment has a configuration in which the sliding contact surface 8 a of the lid member 8 is formed with the chamfered portion 8 b for reducing the sliding contact area between the lid member 8 and the external gear 2. By reducing the area where the external gear 2 and the sliding contact surface 8a of the lid member 8 are in sliding contact with each other, a large force of fluid is always applied to the external gear 2 from the sliding contact surface 7a side of the housing hole 7. Since the position of the external gear 2 is always set to the Y position which is close to the sliding contact surface 8a of the lid member 8, the fluid having a high pressure in the working chamber 10 on the discharge port 18, 20 side is It is possible to reduce the amount of leakage in the direction of the rotating shaft 1 from the gap between the side surfaces on both sides of the external gear 2, and to improve the storage efficiency of the pump.

【００２０】 上記実施例は、蓋部材８の摺接面８ａに面取り部８ｂを形成して、蓋部材８と 外歯歯車２の間の摺接面積を小さくしているが、蓋部材８と外歯歯車２の間の摺 接面積を小さくする構成として面取り部８ｂに限定するものではなく、例えば摺 接面８ａにへこみ部を形成した構成にしてもよい。In the above embodiment, the chamfered portion 8b is formed on the sliding contact surface 8a of the lid member 8 to reduce the sliding contact area between the lid member 8 and the external gear 2. The configuration for reducing the sliding contact area between the external gears 2 is not limited to the chamfered portion 8b, and for example, a configuration in which a recessed portion is formed on the sliding contact surface 8a may be used.

【００２１】[0021]

【考案の効果】 以上述べたように、本願考案は、ポンプ本体の側面に開口する収装孔内に、こ の収装孔の底部に位置する軸受部で前記ポンプ本体に対して回転可能に軸支され た外歯歯車と、この外歯歯車に対して偏心して内接噛合した内歯歯車を回転自在 に収納し、前記収装孔の側面に蓋部材を取り付けて前記収装孔を閉塞して、前記 両歯車を前記収装孔及び前記蓋部材の摺接面に摺接させ、前記両歯車で区画され る作用室へ吸入ポートより流体を吸入するとともに、吐出ポートより流体を吐出 する液圧ポンプにおいて、前記蓋部材の摺接面に、前記蓋部材の摺接面から前記 外歯歯車よ流体によって作用する力が前記収装孔の摺接面から前記外歯歯車に流 体によって作用する力より小さくなるように摺接面積を小さくする凹部を形成し たことを特徴とし、外歯歯車の両側面のうち、軸受部の絞り部がなく流体の漏れ が多い蓋部材に摺接する面の受圧面積を、凹部を形成したことで小さくして、外 歯歯車の位置を蓋部材に摺接する面に近づけたことで、外歯歯車の側面からの漏 れを減少させることができ、容積効率を向上することができる。As described above, according to the invention of the present application, the inside of the storage hole that is opened on the side surface of the pump body is rotatable with respect to the pump body by the bearing portion located at the bottom of the storage hole. The rotatably housed axially supported external gear and the internal gear that is eccentrically and internally meshed with the external gear are rotatably accommodated, and a lid member is attached to the side surface of the storage hole to close the storage hole. Then, the both gears are brought into sliding contact with the sliding contact surfaces of the housing hole and the lid member to suck the fluid into the action chamber defined by the both gears from the suction port and discharge the fluid from the discharge port. In the hydraulic pump, a force acting on the sliding contact surface of the lid member by the fluid from the sliding contact surface of the lid member is applied to the external gear by the fluid from the sliding contact surface of the storage hole. Form a recess that reduces the sliding contact area so that it is smaller than the acting force. Among the two side surfaces of the external gear, the pressure receiving area of the surface that is in sliding contact with the lid member that does not have the throttle part of the bearing part and has a large amount of fluid leakage is reduced by forming the concave part, By making the position of the gear closer to the surface in sliding contact with the lid member, it is possible to reduce leakage from the side surface of the external gear and improve the volumetric efficiency.

【図面の簡単な説明】[Brief description of drawings]

【図１】本考案の実施例を示す液圧ポンプの側面図であ
る。FIG. 1 is a side view of a hydraulic pump showing an embodiment of the present invention.

【図２】本考案の実施例を示す図１のＡ−Ａ線断面図で
ある。FIG. 2 is a sectional view taken along line AA of FIG. 1 showing an embodiment of the present invention.

【図３】本考案の実施例の外歯歯車の両側面の圧力分布
を示す図である。FIG. 3 is a diagram showing a pressure distribution on both side surfaces of the external gear according to the embodiment of the present invention.

【図４】外歯歯車が収装孔の摺接面に近づいた位置の状
態を示す説明図である。FIG. 4 is an explanatory view showing a state in which an external gear is located near a sliding contact surface of a mounting hole.

【図５】外歯歯車が蓋部材の摺接面に近づいた位置の状
態を示す説明図である。FIG. 5 is an explanatory view showing a state in which the external gear is close to the sliding contact surface of the lid member.

【図６】外歯歯車が収装孔の摺接面に近づいた位置と蓋
部材の摺接面に近づいた位置の吐出量を比較する図であ
る。FIG. 6 is a diagram comparing discharge amounts at a position where an external gear approaches a sliding contact surface of a housing hole and a position where the external gear approaches a sliding contact surface of a lid member.

【図７】従来技術の外歯歯車の両側面の圧力分布を示す
図である。FIG. 7 is a diagram showing pressure distribution on both side surfaces of a conventional external gear.

【符号の説明】[Explanation of symbols]

１ 回転軸 ２ 外歯歯車 ４ 内歯歯車 ６ ポンプ本体 ６ａ 側面 ７ 収納孔 ７ａ 摺接面 ７ｂ 軸受部 ８ 蓋部材 ８ａ 摺接面 ８ｂ 面取り部（凹部） １０ 作用室 １２，１４ 吸入ポート １８，２０ 吐出ポート DESCRIPTION OF SYMBOLS 1 rotary shaft 2 external gear 4 internal gear 6 pump body 6a side 7 storage hole 7a sliding contact surface 7b bearing 8 lid member 8a sliding contact 8b chamfer (recess) 10 working chamber 12, 14 suction port 18, 20 Discharge port

Claims (1)

【実用新案登録請求の範囲】[Scope of utility model registration request] 【請求項１】 ポンプ本体の側面に開口する収装孔内
に、この収装孔の底部に位置する軸受部で前記ポンプ本
体に対して回転可能に軸支された外歯歯車と、この外歯
歯車に対して偏心して内接噛合した内歯歯車を回転自在
に収納し、前記収装孔の側面に蓋部材を取り付けて前記
収装孔を閉塞して、前記両歯車を前記収装孔及び前記蓋
部材の摺接面に摺接させ、前記両歯車で区画される作用
室へ吸入ポートより流体を吸入するとともに、吐出ポー
トより流体を吐出する液圧ポンプにおいて、前記蓋部材
の摺接面に、前記蓋部材の摺接面から前記外歯歯車よ流
体によって作用する力が前記収装孔の摺接面から前記外
歯歯車に流体によって作用する力より小さくなるように
摺接面積を小さくする凹部を形成したことを特徴とする
液圧ポンプ。1. An external gear, which is rotatably supported by a bearing portion located at the bottom of the pumping hole in the pumping hole that is open to the side surface of the pump body, and an external gear. An internal gear, which is eccentrically and internally meshed with a tooth gear, is rotatably housed, a lid member is attached to a side surface of the housing hole to close the housing hole, and the both gears are housed in the housing hole. And a sliding contact surface of the lid member, which sucks fluid from a suction port into a working chamber defined by the both gears and discharges fluid from a discharge port. The surface has a sliding contact area so that the force exerted by the fluid from the sliding contact surface of the lid member is smaller than the force exerted by the fluid from the sliding contact surface of the storage hole on the external gear. A hydraulic pump characterized in that a recess for reducing the size is formed.