JPH0486379A - Axial piston pump - Google Patents

Abstract

PURPOSE:To uniform the face pressure acting between the mutual sliding surfaces of a cylinder block and a valve plate and completely suppress partial abrasion and seizure easy to generate on both the sliding surfaces by shifting the center of each bore opening in anti-rotating direction to the bore center. CONSTITUTION:In the sliding surface 31 part of a valve plate 30, an intake port 32 and discharge port 32 forming opposed circular forms in accord with the rotating orbit of a bore opening 23 are bored. The bore opening 23 is formed into an elliptic form curved along the rotating orbit, and its longitudinal (circumferential) center is offset in anti-rotating direction (bottom dead point B.D side) to the center of a bore 22. A dissociating force S based on the oil film pressure between sliding surfaces 21, 31 enclosing the bore opening 23 is worked with deviation to the anti-rotating direction or the bottom dead point B.D side to a pressing force P opposed thereto. Thus, the face pressure between the sliding surfaces 21, 31 in discharge area is held uniform, and a partial abrasion easy to generate, particularly, the lower dead point B.D side of the valve plate 30 is prevented.

Description

【発明の詳細な説明】 ［産業上の利用分野］ 本発明は、該機械の油圧作動系に用いられるアキシヤル
ピストンポンプに関覆る。DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an axial piston pump used in the hydraulic system of the machine.

［従来の技術］ アキシャルピストンポンプの中でも固定斜板型式のポン
プ（以下、単にポンプという）は、各種産業機械や産業
車両などに広く使用されており、第３図はとくに斜板傾
角の調節ａ構を装備した可変容量形のポンプを例示した
ものである。[Prior Art] Among axial piston pumps, fixed swash plate type pumps (hereinafter simply referred to as pumps) are widely used in various industrial machines and industrial vehicles. This is an example of a variable displacement pump equipped with a mechanism.

同ポンプは、ケーシング１及びその開放端を閉止するエ
ンドカバー２によって密封状の動作空間３が形成され、
この動作空間３内に挿入された駆動軸４は、これら両部
材１．２に軸受５を介して支承されている。駆動軸４に
結合され動作空間３内において駆動軸４と一体的に回転
するシリンダブロック６には、その軸心の周りに軸心と
ほぼ平行な複数のボア７が形成され、同ボア７内にはシ
ュー８を介して斜板９に係留されたピストン１０が１＋
復動可能に挿嵌されている。The pump has a sealed operating space 3 formed by a casing 1 and an end cover 2 that closes the open end of the casing 1.
A drive shaft 4 inserted into this operating space 3 is supported by these two members 1.2 via bearings 5. A cylinder block 6 that is connected to the drive shaft 4 and rotates integrally with the drive shaft 4 within the operating space 3 has a plurality of bores 7 formed around its axis that are approximately parallel to the axis. The piston 10 moored to the swash plate 9 via the shoe 8 is 1+
It is inserted so that it can move backwards.

また、エンドカバー２に固定されて各ボア７の量目端面
を封止する弁板１１には、ボア間ロアａの回転軌跡と符
合して対向円弧状をなす吸入ポ１〜１２ａ及び吐出ボー
　１〜１２　ｂか穿設され、同ボ１〜１２ａ、１２ｂは
これと同一形状に形成されたエンドカバー２の吸入及び
吐出［］１３ａ、１３ｂの端縁と整合ずべく構成されて
いる。したがって、駆動１ｌＩｌｌ１４と共動りるシリ
ンダシ［］ツク６の回転に伴い、斜板９に係召されて直
動するビス１〜ン１０がボア７の密閉空間容積を拡大す
る傾向にあるとぎ、同ボア７は吸入ポート１２ａと対応
して作動油を吸入し、逆にピストン１０がボア７の密閉
空間容積を縮小する傾向にあるとき、同ボア７は吐出ポ
ート１２ｂと対応して作動油を吐出量るようになされて
いる。なお、図示しない支軸に枢支された斜板９は何勢
部ｖＪ１／ｌにより常に傾角を増大する向きにイ」勢さ
れてあり、これに対抗覆る制御体１５を流体圧によって
進退動せしめることにより、斜板傾角つまりポンプ１回
転当りの理論吐出量が変更調節可能に構成されている。In addition, a valve plate 11 that is fixed to the end cover 2 and seals the end face of each bore 7 has suction ports 1 to 12a and discharge ports that form opposing circular arcs in line with the rotation locus of the inter-bore lower a. 1 to 12b are bored, and the holes 1 to 12a and 12b are configured to align with the edges of the suction and discharge ports 13a and 13b of the end cover 2, which are formed in the same shape as the holes 1 to 12b. Therefore, with the rotation of the cylinder cylinder 6 that moves together with the drive 11114, the screws 1 to 10 that are engaged with the swash plate 9 and move directly tend to expand the volume of the sealed space of the bore 7. The bore 7 corresponds to the suction port 12a and sucks hydraulic oil, and conversely, when the piston 10 tends to reduce the volume of the sealed space of the bore 7, the bore 7 corresponds to the discharge port 12b and sucks hydraulic oil. The amount of discharge is controlled. Incidentally, the swash plate 9, which is pivotally supported on a support shaft (not shown), is always urged in a direction to increase the inclination angle by a force member vJ1/l, and the control body 15 that counters this is moved forward and backward by fluid pressure. As a result, the swash plate inclination angle, that is, the theoretical discharge amount per revolution of the pump can be changed and adjusted.

そして上述したポンプにおりるボア７は、作動油の円滑
な出入を図るため、ボア開ロア８部分かボア７よりも小
さな断面積をもら、かつその多くは回転軌跡に沿って湾
曲した長孔状に形成され、しかもその両端縁は例えば特
開昭４．８−８７４０６号公報にも開示されているよう
に、ボア７の内周面と接するように配設されている（第
４図）。The bore 7 in the pump mentioned above has a cross-sectional area smaller than the bore opening lower 8 portion or the bore 7 in order to allow the hydraulic fluid to enter and exit smoothly, and most of the bores are elongated holes curved along the rotation locus. It is formed into a shape, and both edges thereof are arranged so as to be in contact with the inner circumferential surface of the bore 7, as disclosed in, for example, Japanese Patent Application Laid-open No. 4.8-87406 (FIG. 4). .

つまり、ボア７の中心とボア聞ロアａの長手方向の中心
とは同心状に整合せしめられているのが一般的である。In other words, the center of the bore 7 and the longitudinal center of the bore lower a are generally aligned concentrically.

［発明が解決しようとする課題］ さて、シリンダブロック６か弁板１１と摺動じながら回
転覆る際、シリンダブ［ｌツク６には吐出される圧力媒
体（作動油）を介して強大な押付力が作用するが、同時
に斜板９の反力として生じる軸直角方向（下死点１３・
Ｄニア’ｆ向）の分力「がシリンダブロック６を同方向
へ傾倒せしめるイ」勢力として作用し、その結果、吐出
領域において弁板１１との摺動面間に働く押付力の中心
位置は実質的に下死点Ｂ　−Ｄ側へ転移する。[Problems to be Solved by the Invention] Now, when the cylinder block 6 and the valve plate 11 are rotated while sliding, a strong pressing force is applied to the cylinder block 6 through the discharged pressure medium (hydraulic oil). However, at the same time, the reaction force of the swash plate 9 occurs in the direction perpendicular to the axis (bottom dead center 13,
The component force "D near 'f direction)" acts as a force to tilt the cylinder block 6 in the same direction, and as a result, the center position of the pressing force acting between the sliding surface with the valve plate 11 in the discharge region is Substantially moves to the bottom dead center B-D side.

しかしながら、従来のシリンダブロック６は、上述のよ
うにボア７の中心とボア開ロアａの長手方向の中心とか
整合せしめられでおり、上記分力「の影響を磨外祝すれ
ば、ボア７を介して上記摺動面間に働く押（ｑツノと、
ボア聞ロアａを取巻く摺動面間の油膜圧力に基づく開離
力とは、その中心位置（点Ａ）が全く一致する構成とな
されている。However, in the conventional cylinder block 6, as mentioned above, the center of the bore 7 is aligned with the longitudinal center of the bore opening lower a. A pusher (q-horn and
The center position (point A) of the separation force based on the oil film pressure between the sliding surfaces surrounding the bore and the lower a coincides completely.

したがって、上記分力Ｆによる押付力中心位置の（点Ｂ
〉への転移は摺動面間の圧力バランスに変動を生じ、弁
板１１の吐出ボー１へ１２ｂを囲繞する摺動面１１ａの
うち下死点Ｂ−Ｄ寄りかとくに強圧される結果、当該部
分に偏摩耗が進行して容積効率が低下し、果ては焼側な
ど重大な事故を誘発する虞れがある。Therefore, the center position of the pressing force due to the above component force F (point B
The transition to > causes a fluctuation in the pressure balance between the sliding surfaces, and as a result, pressure is particularly strong on the sliding surface 11a surrounding the discharge bow 12b of the valve plate 11 near the bottom dead center B-D. Uneven wear progresses on the parts, reducing volumetric efficiency, which may even lead to serious accidents such as on the burning side.

本発明はシリンダブロック、弁仮相ｑの摺動面間に働く
血圧の均一化を図ることを、解決すべき技術課題とする
ものである。A technical problem to be solved by the present invention is to equalize the blood pressure acting between the sliding surfaces of the cylinder block and the valve phase q.

［課題を解決するための手段］ 上記課題解決のため、本発明の各ボア開口の中心はボア
中心に対して反回転方向に偏在せしめられているという
新規な構成を採用している。[Means for Solving the Problems] In order to solve the above problems, the present invention adopts a novel configuration in which the center of each bore opening is unevenly distributed in the counter-rotational direction with respect to the bore center.

［作用］ 各ボア開口の中心は、ボア中心に対して反回転方向（不
死点側）に偏在せしめられており、吐出領域にお（プる
各ボア開口周辺の摺動面間には油膜圧ツノによって下死
点側を開離させ、上死点側を押付けようとするモーメン
１〜か動く。これにより開離力の中心位置と押イ」力（
斜板反力の軸直角方向弁ツノを含む）の中心位置とがほ
ぼ整合し、摺動面間の血圧の均一化が達成される。[Function] The center of each bore opening is unevenly distributed in the counter-rotational direction (to the dead center side) with respect to the bore center, and there is an oil film pressure between the sliding surfaces around each bore opening in the discharge area. The horn moves the bottom dead center side apart and presses the top dead center side. This causes the center position of the opening force and the pushing force (
The center position of the swash plate reaction force (including the valve horn in the direction perpendicular to the axis) is substantially aligned with the center position of the swash plate reaction force, thereby achieving uniformity of blood pressure between the sliding surfaces.

［実施例］ 以下、図に基づいて本発明の実施例を具体的に説明する
。なお、アキシャルピストンポンプの基本的な構成は従
来ととくに変るところはないので、同一の構成要素には
同一の符号を付して詳しい説明は省略する。[Example] Hereinafter, an example of the present invention will be specifically described based on the drawings. Note that, since the basic configuration of the axial piston pump is not particularly different from the conventional one, the same components are given the same reference numerals and detailed explanations will be omitted.

第１図は弁板の摺動向側を表し、第２図はボア中心の局
部断面を示したものであって、第１図には等分に配置さ
れたボア（２点鎖線で示ず〉のうちの１個が上死点Ｔ−
Ｄ位置へ周来した状態が画かれている。Figure 1 shows the sliding direction side of the valve plate, and Figure 2 shows a local cross section at the center of the bore. One of them is at top dead center T-
The state in which it has come around to the D position is depicted.

図において、弁板３０の摺動面３１部分には、ボア開口
２３の回転軌跡と符合して対向円弧状をなず吸入ポート
３２及び吐出ポート３３が穿設され、所要の幅員をもっ
て該両ポート３２．３３を囲包するように形成された環
状の摺動面３１は、シリンダブロック２０の相対的な１
門動面２１とも整合して、その内外周域が逃げ面として
僅かに段差状に避退せしめられている。なお、本例の上
記吐出ボー１〜３３は吐出行程の不規則化によって吐出
脈動の低減を図るべく３個に分割して配設されており、
また、両ポート３２．３３の始端部にはボア開口２３と
の連通をＪ：り円滑ならしめる三角状のり欠３４が刻設
されている。In the figure, a suction port 32 and a discharge port 33 are bored in the sliding surface 31 of the valve plate 30 in a circular arc shape facing each other in line with the rotation locus of the bore opening 23, and the two ports are provided with a required width. The annular sliding surface 31 formed so as to surround 32 and 33 is a relative one of the cylinder block 20.
It is also aligned with the gate movement surface 21, and its inner and outer circumferential regions are retracted slightly into steps as relief surfaces. In addition, the above-mentioned discharge bows 1 to 33 in this example are arranged in three parts in order to reduce discharge pulsation by making the discharge stroke irregular.
Furthermore, a triangular notch 34 is cut into the starting end of both ports 32 and 33 to smooth the communication with the bore opening 23.

そして本発明の最も重要な特徴である上記ボア開口２３
は、回転軌跡に沿って湾曲した長孔状に形成され、かつ
その長手方向（円周方向）の中心はボア２２中心に対し
て反回転方向（不死点Ｂ・Ｄ側）に偏在せしめられてお
り、図には位相差中心角αとして示されている。The bore opening 23 is the most important feature of the present invention.
is formed in the shape of a long hole curved along the rotation locus, and its center in the longitudinal direction (circumferential direction) is unevenly located in the counter-rotation direction (toward the dead center B and D side) with respect to the center of the bore 22. This is shown as the phase difference central angle α in the figure.

既述したようにアキシャルビス１〜ンボンプにおいては
、シリンダブロック２０か弁板３０と１門動しながら回
転覆る際、シリンダブロック２０には吐出される圧力媒
体（作動油）を介して強大な押付力Ｐか作用するか、同
時に斜板９の反力とじて生じる軸直角方向（下死点Ｂ−
Ｄ方向）の分力「がシリンダブロック２０を同方向へ傾
倒せしめる付勢力として作用し、その結果、吐出領域に
おいて摺動面２１．３１間に動く押付力Ｐの中心位置は
実質的に下死点Ｂ−Ｄ側へ転移する（第３図）。As mentioned above, when the axial screws 1 to 1 are rotated over each other while moving with the cylinder block 20 and the valve plate 30, the cylinder block 20 is subjected to strong pressure through the discharged pressure medium (hydraulic oil). The direction perpendicular to the axis (bottom dead center B-
D direction) acts as a biasing force to tilt the cylinder block 20 in the same direction, and as a result, the center position of the pressing force P that moves between the sliding surfaces 21 and 31 in the discharge area is substantially at the bottom dead end. It moves to the point B-D side (Fig. 3).

すなわち第１図の状態において、吐出領域にあるボア２
２中心にはそれぞれ押付力Ｐが作用し−Ｃおり、その場
合の総合的な押付力Ｐの範囲は中心角Ｍ、押付力Ｐの中
心位置は点Ａとなるのであるが、上記分力「の影響によ
り同抑圧力Ｐの中心位置は点Ｂへと下死点Ｂ−Ｄ側へ転
移する。That is, in the state shown in Fig. 1, the bore 2 in the discharge area
A pressing force P acts on each of the two centers, and in that case, the range of the overall pressing force P is the center angle M, and the center position of the pressing force P is point A, but the above component force `` Due to the influence of , the center position of the suppressing force P shifts to point B and toward the bottom dead center B-D side.

しかしながら、本例のボア開口２３はボア２２中心に対
して上記位相差中心角α分、反回転方向に偏在して設Ｃ
ブられているため、各ボア開口２３を囲む摺動面２Ｌ　
３１間の油膜圧力に基づく開離力Ｓは、対向する押付力
１つに対して反回転方向すなわち下死点Ｂ−Ｄ側へ偏っ
て作用することとなり、同開離力Ｓによって摺動面２１
．３１間には下死点Ｂ−Ｄ側を間離させ、十死点丁・Ｄ
側を押付ようとするモーメンｉ〜が働く。その場合の総
合的な開離力Ｓの範囲は中心角Ｎとして示されており、
開離力Ｓの中心位置も上記分力−を含む押付力Ｐの中心
位置点Ｂにきわめて近接若しくは整合される。したがっ
て、吐出領域におりる摺動面２Ｌ　３１間の血圧はほぼ
均一に保たれ、弁板３０のとくに下死点Ｂ−Ｄ側に生じ
易い偏摩耗は合理的に防止される。However, the bore opening 23 of this example is unevenly located in the counter-rotational direction by the phase difference center angle α with respect to the center of the bore 22.
Since the sliding surface 2L surrounding each bore opening 23 is
The separation force S based on the oil film pressure between 21
．． 31, the bottom dead center B-D side is spaced apart, and the ten dead center D
A moment i~ tries to press the side. The range of the overall opening force S in that case is shown as the central angle N,
The center position of the separation force S is also very close to or aligned with the center position point B of the pressing force P including the component force -. Therefore, the blood pressure between the sliding surfaces 2L and 31 in the discharge region is maintained substantially uniform, and uneven wear of the valve plate 30, which tends to occur particularly on the bottom dead center B-D side, is rationally prevented.

なお、本実施例においては、ボア開口２３が回転軌跡に
沿って湾曲した長孔状に形成されているが、これに限ら
ず単に円形断面のボア開口２３としてもよく、要はその
中心がボア中心に対して反回転方向に偏在しておれば十
分である。In this embodiment, the bore opening 23 is formed in the shape of a long hole curved along the rotation locus, but the bore opening 23 is not limited to this, and may simply have a circular cross section. It is sufficient that they are unevenly distributed in the counter-rotational direction with respect to the center.

［発明の効果］ 以上、詳述したように本発明は、ボア開口の中心をボア
７中心から反回転方向に偏在せしめて、シリンダブロッ
ク、弁板間の摺動面に生じる開離力の作用点を下死点側
へ移動させたものであるから、これが斜板反力の軸方向
分力により実質的に下死点側に転移する押付力と拮抗し
て、該摺動面間の血圧をほぼ均一に保持するので、両店
動面に生起し易い偏摩耗や焼イ」は完全に抑止され、ポ
ンプの性能並びに耐久性を格段と向上させることができ
る。[Effects of the Invention] As described in detail above, the present invention makes the center of the bore opening unevenly distributed in the counter-rotational direction from the center of the bore 7, thereby reducing the effect of the opening force generated on the sliding surface between the cylinder block and the valve plate. Since the point is moved toward the bottom dead center, this counteracts the pressing force that is substantially transferred to the bottom dead center due to the axial component of the swash plate reaction force, and the blood pressure between the sliding surfaces increases. Since it maintains almost uniformity, uneven wear and burning that tend to occur on both moving surfaces are completely suppressed, and the performance and durability of the pump can be significantly improved.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は本発明の一実施例であって、ボア及びボア開口
と対応する弁板の）門動面側を示す側面図、第２図は同
じく押付力と開離力との作用状態を示すボア中心の部分
断面図、第３図は従来のアキシャルビス１〜ンボンプの
全容を示づ断面図、第４図は従来の弁板の摺動向側を示
す第１図と同一形態の側面図で必る。 ２０・・・シリンダブロック ２１・・・摺動面　　　　２２・・・ボア２３・・・ボ
ア開口　　　３０・・・弁板３１・・・摺動面　　　　
３２・・・吸入ポート３３・・・吐出ポートFig. 1 shows an embodiment of the present invention, and is a side view showing the gate movement side (of the valve plate corresponding to the bore and the bore opening), and Fig. 2 similarly shows the operating state of the pressing force and the separating force. FIG. 3 is a cross-sectional view showing the entire structure of a conventional axial screw 1 to pump, and FIG. 4 is a side view of the same form as FIG. 1 showing the sliding side of a conventional valve plate. It is necessary. 20... Cylinder block 21... Sliding surface 22... Bore 23... Bore opening 30... Valve plate 31... Sliding surface
32...Suction port 33...Discharge port

Claims (1)

【特許請求の範囲】[Claims] （１）駆動軸と共に回転するシリンダブロックの軸心の
周りに該軸心とほぼ平行な複数のボアを有し、各ボアに
はシユーを介して斜板と係留するピストンが挿嵌される
とともに、これらボアの開口端面を封止する弁板には、
ボア開口の回転軌跡と符合して対向円弧状をなす吸入及
び吐出ポートが穿設され、該両ポートはそれぞれ吸入及
び吐出口端と整合すべく構成されたアキシヤルピストン
ポンプにおいて、上記各ボア開口の中心はボア中心に対
して反回転方向に偏在せしめられていることを特徴とす
るアキシャルピストンポンプ。(1) The cylinder block that rotates with the drive shaft has a plurality of bores around the axis that are approximately parallel to the axis, and a piston that is moored to the swash plate is inserted into each bore through a shoe. , the valve plate that seals the open end faces of these bores has
In an axial piston pump, suction and discharge ports are formed in opposing circular arc shapes in alignment with the rotation locus of the bore openings, and the ports are configured to align with the suction and discharge port ends, respectively. An axial piston pump characterized in that the center of the pump is unevenly located in the counter-rotational direction with respect to the center of the bore.