JPH06159230A - Swash plate type piston pump or motor - Google Patents
Swash plate type piston pump or motorInfo
- Publication number
- JPH06159230A JPH06159230A JP4337959A JP33795992A JPH06159230A JP H06159230 A JPH06159230 A JP H06159230A JP 4337959 A JP4337959 A JP 4337959A JP 33795992 A JP33795992 A JP 33795992A JP H06159230 A JPH06159230 A JP H06159230A
- Authority
- JP
- Japan
- Prior art keywords
- cylinder block
- piston
- motor
- hardness
- swash plate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
- F05C2201/00—Metals
- F05C2201/04—Heavy metals
- F05C2201/0433—Iron group; Ferrous alloys, e.g. steel
- F05C2201/0448—Steel
- F05C2201/0457—Cemented steel
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
- F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
- F05C2253/00—Other material characteristics; Treatment of material
- F05C2253/12—Coating
Landscapes
- Reciprocating Pumps (AREA)
- Details Of Reciprocating Pumps (AREA)
- Hydraulic Motors (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、斜板型ピストンポンプ
またはモータに関し、より詳細には鋳鉄製シリンダブロ
ックのシリンダの内面がブッシュを設けない鋳鉄のまま
であるものに用いるピストンが焼け付きを起こしにくい
ものに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swash plate type piston pump or motor, and more particularly to a cast iron cylinder block in which the inner surface of the cylinder is cast iron without bushing. Regarding things that are hard to cause.
【０００２】[0002]
【従来の技術】安価であることを第１の目的として製作
される斜板型ピストンポンプまたはモータの場合、その
シリンダブロックを鋳鉄とし、シリンダ内周面には銅合
金製等のブッシュを用いない構成で鋳鉄面をそのまま又
はタフトライド処理（窒化処理）を施したものとし、ピ
ストンにはクロムモリブデン鋼を用いて浸炭焼き入れ処
理をしたものとすることが行われていた。2. Description of the Related Art In the case of a swash plate type piston pump or motor whose primary purpose is to be inexpensive, the cylinder block is made of cast iron, and a bush made of copper alloy or the like is not used on the inner peripheral surface of the cylinder. In the structure, the cast iron surface is used as it is or is subjected to a tuftride treatment (nitriding treatment), and the piston is made to be carburized and quenched using chrome molybdenum steel.
【０００３】[0003]
【発明が解決しようとする課題】このような斜板型ピス
トンポンプまたはモータは、例えば、建設機械の走行用
モータとして使用されるが、ある程度以上の高速で運転
されると銅合金製ブッシュを使用したものには見られな
い焼け付きが発生する欠点がある。従って、通常は２５
００ｒ．ｐ．ｍ．程度以下で使用されており、回転数を
さらに上げて使用すると焼け付きを起こす問題があっ
た。この焼け付き防止対策として、ピストンとシリンダ
の隙間を大きくして摺動面がより良く冷却されるように
することがあるが、隙間を大きくすると起動時の機械効
率の低下と外部ドレン量の増大をまねく点で問題があ
る。本発明は、この種の斜板型ピストンポンプまたはモ
ータに使用して焼け付きを起こし難いピストンを提供し
て、より高速回転で使用できるようにすることを目的と
する。Such a swash plate type piston pump or motor is used, for example, as a traveling motor for a construction machine, but when it is operated at a high speed above a certain level, a copper alloy bush is used. There is a defect that burn-in occurs, which is not seen in the above. Therefore, usually 25
00r. p. m. It is used below a certain level, and there is a problem that burn-in occurs when the rotation speed is increased further. As a measure to prevent this seizure, it may be necessary to increase the clearance between the piston and cylinder so that the sliding surface is cooled better.However, increasing the clearance reduces the mechanical efficiency at startup and increases the amount of external drain. There is a problem in that it leads to. An object of the present invention is to provide a swash plate type piston pump or motor of this type that is resistant to seizure and can be used at higher speeds.
【０００４】[0004]
【課題を解決するための手段】本発明の手段は、シリン
ダ内周面が鋳鉄材質そのままもしくは窒化処理したシリ
ンダブロックと、このシリンダブロックに組み合わせて
使用されるピストンであって、材質が窒化可能な鋼であ
り、調質して素地硬度を上げたものに窒化処理を施し、
周面の硬化した表面層のうち高硬度層を除去して素地硬
度よりも高い硬度層を残したものとを具備することを特
徴とする。[Means for Solving the Problems] The means of the present invention is a cylinder block whose inner peripheral surface is cast iron or a nitriding cylinder block, and a piston which is used in combination with this cylinder block. Steel, which has been tempered to increase the hardness of the base material, is subjected to nitriding treatment,
The hardened surface layer of the peripheral surface is removed to leave a hardened layer having a hardness higher than the base hardness.
【０００５】[0005]
【作用】窒化処理を施すと、例えば、タフトライド５時
間処理で０．５ｍｍ程度の表面硬化層ができる。その硬
化層の硬度分布状態は、表面において最も硬く、内側に
移動するにしたがって素地硬度に近づく。タフトライド
処理されたピストンをそのままの状態で使用すると、短
時間で硬化層が１０〜２０μｍ程部分的に剥離してしま
い、剥離境界の段付き部によりシリンダブロック内周面
を削り取る。しかし、硬化した表面層のうち高硬度層を
除去して、例えば表面から２０μｍ程度除去して使用す
ると、硬化した表面層の剥離が生じなくなり、また、従
来よりピストン速度を上げても焼け付きが生じなくな
る。すなわち、焼け付く限界速度が高くなる。本発明に
おいて用いられる窒化可能な鋼としては、構造用鋼の他
に、窒化鋼として知られるクロムモリブデン鋼、アルミ
ニュームクロムモリブデン鋼、クロムバナジュウム鋼、
ニッケルクロムアルミニュームモリブデン鋼等が挙げら
れる。When the nitriding treatment is performed, for example, a surface hardened layer having a thickness of about 0.5 mm can be formed by the treatment with tuftride for 5 hours. The hardness distribution of the hardened layer is the hardest on the surface, and approaches the substrate hardness as it moves inward. When the tufftride-treated piston is used as it is, the hardened layer is partially peeled off by about 10 to 20 μm in a short time, and the stepped portion of the peeling boundary scrapes off the inner peripheral surface of the cylinder block. However, if the high hardness layer of the cured surface layer is removed, for example, by removing from the surface by about 20 μm, peeling of the cured surface layer does not occur, and seizure does not occur even if the piston speed is increased from the conventional value. It will not occur. That is, the critical speed for burning is increased. Examples of the nitridable steel used in the present invention include, in addition to structural steel, chromium molybdenum steel known as nitrided steel, aluminum chrome molybdenum steel, chrome vanadium steel,
Nickel chrome aluminum molybdenum steel and the like can be mentioned.
【０００６】[0006]
【実施例】以下本発明の一実施例を説明する。この実施
例の斜板型ピストンモータはの概略の構成は図１に示す
ようになっている。図１（ａ）において、１は本体、２
はこの本体１に設けた内孔である。３は、この内孔２を
貫通し本体１に回転自在に支承される回転軸である。４
はシリンダブロックで、回転軸３にスプラインで連結し
てあり、複数本のピストン５ａ、５ｂが摺動自在に嵌入
される孔４ａ、４ｂ穿設してある。７は、前記ピストン
５ａ、５ｂがシュー６ａ、６ｂを介して当接する斜板
で、本体１の内孔に２位置に傾転可能に設けてある。８
は、弁板で、シリンダブロック４の左端面と本体１の内
孔を閉鎖する蓋体９との間に設けてあり、シリンダブロ
ック４の孔４ａ、４ｂに圧油を給排するための半月型
（図示しない）のポートを有する。EXAMPLE An example of the present invention will be described below. The schematic structure of the swash plate type piston motor of this embodiment is as shown in FIG. In FIG. 1A, 1 is a main body, 2
Is an inner hole provided in the main body 1. Reference numeral 3 denotes a rotary shaft that penetrates the inner hole 2 and is rotatably supported by the main body 1. Four
Is a cylinder block, which is connected to the rotary shaft 3 by a spline, and is provided with holes 4a and 4b into which a plurality of pistons 5a and 5b are slidably fitted. Reference numeral 7 denotes a swash plate with which the pistons 5a and 5b come into contact with each other via shoes 6a and 6b, and is provided in an inner hole of the main body 1 so as to be tiltable in two positions. 8
Is a valve plate that is provided between the left end surface of the cylinder block 4 and the lid 9 that closes the inner hole of the main body 1, and is a half-moon for supplying and discharging pressure oil to the holes 4a and 4b of the cylinder block 4. It has a port of a mold (not shown).
【０００７】上記アキシャル型のピストンモータにおい
て、圧油が、弁板８を介してシリンダブロック４の孔４
ａ、４ｂに給排される。（なお、シリンダブロック４の
孔４ａ、４ｂは、９個あり、油圧がこの９本の孔４ａ、
４ｂの内の４個に供給され他の５個の孔内の油が排出さ
れる状態と、圧油が５個の孔４ａ、４ｂに供給され他の
４個の孔内の油が排出される状態との２つの状態に弁板
８が孔４ａ、４ｂへの圧油の給排を制御する。）すると
圧油が給排された孔に摺動自在に嵌入しているピストン
は、斜板７の斜面から受ける分力で、シリンダブロック
４が回転軸３と共に回転させられる。In the above axial type piston motor, the pressure oil passes through the valve plate 8 and the hole 4 of the cylinder block 4.
It is supplied to and discharged from a and 4b. (Note that the cylinder block 4 has nine holes 4a and 4b, and the hydraulic pressure is 9 holes 4a and 4b.
4b is supplied to four of the other four holes and oil in the other five holes is discharged, and pressure oil is supplied to the five holes 4a and 4b and oil of the other four holes is discharged. The valve plate 8 controls the supply and discharge of the pressure oil to and from the holes 4a and 4b in two states. Then, the piston, which is slidably fitted in the hole through which the pressure oil is supplied and discharged, causes the cylinder block 4 to rotate together with the rotary shaft 3 by the component force received from the slope of the swash plate 7.
【０００８】上記動作において、図１（ｂ）の拡大図に
示すように、孔４ａに圧油が供給されて、ピストン５ａ
が斜面に押圧力ｆ１で押圧されると、その分力ｆ２の力
をその先端に受ける。この分力ｆ２をピストン５ａが受
け止めるためには、孔４ａの端部（開口端部）４ａ１の
部分にｆ２−１の力が作用し、ピストン５ａの端部５ａ
−２の部分にｆ２−２の力が作用する。一般にこの孔４
ａの端部（開口端部）４ａ１の部分と接触するピストン
の部分に焼け付きが生じやすい。In the above operation, as shown in the enlarged view of FIG. 1 (b), pressure oil is supplied to the hole 4a and the piston 5a
When is pressed against the slope by the pressing force f1, the tip receives the force of the component force f2. In order for the piston 5a to receive the component force f2, the force f2-1 acts on the end portion (opening end portion) 4a1 of the hole 4a, and the end portion 5a of the piston 5a.
The force of f2-2 acts on the -2 part. Generally this hole 4
Burn-in is likely to occur at the portion of the piston that comes into contact with the end portion (open end portion) 4a1 of a.
【０００９】このような斜板型ピストンモータのピスト
ン５ａ、５ｂ及びシリンダブロック４が次のように作ら
れている。すなわち、ピストン５ａ、５ｂは、材質がＳ
ＣＭ４４０、調質した素地硬さがＨｖ３００であり、こ
れにタフトライド処理を施してから、外周面の高硬度層
として２０μｍを研削により除去し、ばふ仕上げしたも
の（表面粗さ０．４Ｓ程度）である。その表面の硬さは
Ｈｖ６５０であった。タフトライド処理を施したこのピ
ストンの断面の硬度分布を図２に示す。調質した段階で
ピストン素地の硬さはＨｖ３００程度であるが、タフト
ライド処理により表面はＨＶ７７０となっており、深さ
方向に向かって低下して０．５５ｍｍ付近で素地の硬さ
になっている。The pistons 5a and 5b and the cylinder block 4 of such a swash plate type piston motor are made as follows. That is, the pistons 5a and 5b are made of S
CM440, the tempered ground hardness is Hv300, and after the tuftride treatment is applied to this, 20 μm is removed as a high hardness layer on the outer peripheral surface by grinding and rough finish (surface roughness about 0.4S) Is. The hardness of the surface was Hv650. FIG. 2 shows the hardness distribution of the cross section of this piston that has been subjected to the tuftride treatment. The hardness of the piston base material is about Hv300 at the time of tempering, but the surface becomes HV770 by the tuftride treatment, which decreases in the depth direction and becomes the hardness of the base material in the vicinity of 0.55 mm. .
【００１０】このピストン５ａ、５ｂとは別に、比較例
としてのピストンを準備した。この比較例のピストン
は、実施例のピストン５ａ、５ｂと同一形状、同一寸
法、略同一材質（ＳＣＭ４２０）のものに、従来の浸炭
焼き入れ処理を施したもの（表面の硬さがＨｖ６９４）
である。A piston as a comparative example was prepared separately from the pistons 5a and 5b. The piston of this comparative example has the same shape, same size, and substantially the same material (SCM420) as the pistons 5a and 5b of the embodiment, and has been subjected to the conventional carburizing and quenching treatment (the surface hardness is Hv694).
Is.
【００１１】実施例、比較例共にシリンダブロックは、
材質がＦＣＤ５０で、シリンダ内面の表面粗さＲmax ＝
１０〜３０Ｓ程度であり、シリンダとピストンとの間隙
が３５〜５０μｍである。In each of the examples and the comparative examples, the cylinder block is
Material is FCD50 and surface roughness of cylinder inner surface is Rmax =
It is about 10 to 30 S, and the gap between the cylinder and the piston is 35 to 50 μm.
【００１２】上記実施例の油圧モータと比較例の油圧モ
ータの比較試験を行った結果を表１に示す。Table 1 shows the results of a comparative test conducted between the hydraulic motor of the above embodiment and the hydraulic motor of the comparative example.
【００１３】[0013]
【表１】 [Table 1]
【００１４】表１について説明すると、所定の負荷を与
えて、回転数が２９００ｒ．ｐ．ｍ．、油圧が３５０kg
f/cm2 、油温度が９５°Ｃの条件で、継続運転した結
果、実施例のものには６０分経過しても変化が見られ
ず、比較例のものは６０分で焼け付きを生じ破損して停
止した。分解してピストンの状況を観察したところ、実
施例のものには摺動面に全く変色は認められず、比較例
のものには幅広くピストン表面が凝着摩耗をおこしてい
ることが認められ、さらに表面硬度がＨｖ４００程に低
下していた。また、実施例のものを、運転条件を変え
て、回転数が３２００ｒ．ｐ．ｍ．、油圧が３５０kgf/
cm2 、油温度が９５°Ｃの条件で、６０分継続運転した
ところ、運転中に異常は発生しなかったが、分解してピ
ストンを観察すると、僅かに発熱による変色が認められ
た。しかし、硬度低下は認められなかった。Referring to Table 1, a predetermined load is applied and the rotation speed is 2900 rpm. p. m. , Hydraulic pressure is 350kg
As a result of continuous operation under the conditions of f / cm 2 and oil temperature of 95 ° C, no change was observed in the example of the invention even after 60 minutes passed, and burning of the comparative example occurred in 60 minutes. Damaged and stopped. When disassembling and observing the situation of the piston, no discoloration was observed on the sliding surface in the example, and it was observed that the piston surface widely caused adhesive wear in the comparative example. Further, the surface hardness was reduced to about Hv400. Further, in the example, the operating speed was changed and the rotation speed was 3200 rpm. p. m. , Hydraulic pressure is 350kgf /
After continuous operation for 60 minutes under conditions of cm 2 and oil temperature of 95 ° C, no abnormality occurred during operation, but when disassembled and the piston was observed, slight discoloration due to heat generation was observed. However, no decrease in hardness was observed.
【００１５】この結果から、実施例のものは従来の浸炭
焼き入れ処理を施したものよりも焼け付き難いものであ
り、従来よりも高速運転が可能なものであると言える。From these results, it can be said that the embodiment is harder to burn than the conventional carburized and quenched material, and can be operated at a higher speed than the conventional one.
【００１６】浸炭焼き入れした比較例のピストンは、摺
動抵抗により発生した熱によってピストン表面の局部が
変態点の温度を越えて軟化し、シリンダブロックと凝着
したと考えられる。実施例のピストンは、化合物がピス
トン表面に形成されていて軟化しにくいと考えられる。
比較例のピストンも凝着部以外では硬度低下が認められ
なかった。このことから、凝着部は、硬度の高いシリン
ダブロックに高硬度のピストンを摺動させているから、
互いになじまないため、円筒度に基づく局部接触に起因
したピストンの部分表面の高温化による焼け付きである
と考えられる。よって、シリンダブロックに銅合金製の
ブッシュを圧入したタイプではなじみ性が良好であるか
ら、実施例のピストンをそのまま適用しても格別の効果
はない。実施例の焼け付き難く、高速運転化のであると
いう効果は、ブッシュを用いない鋳鉄製シリンダブロッ
クと組み合わせた場合の特有の効果である。It is considered that the carburized and hardened piston of the comparative example softened the local portion of the piston surface over the temperature of the transformation point due to the heat generated by the sliding resistance, and adhered to the cylinder block. In the pistons of the examples, it is considered that the compound is formed on the surface of the piston and is not easily softened.
Also in the pistons of the comparative examples, no decrease in hardness was observed except in the adhered part. From this, the adhesion part slides the piston of high hardness on the cylinder block of high hardness,
Since they are not compatible with each other, it is considered that the partial surface of the piston is burnt due to a high temperature due to local contact based on cylindricity. Therefore, since the type in which the bush made of copper alloy is press-fitted into the cylinder block has good conformability, there is no particular effect even if the piston of the embodiment is applied as it is. The effect of being hard to burn and high-speed operation of the embodiment is a unique effect when combined with a cast iron cylinder block that does not use a bush.
【００１７】上記実施例では、タフトライド処理を適用
したが、この他にも通常の窒化、軟窒化等を適用しても
よい。In the above embodiment, the tufftride process is applied, but other than this, ordinary nitriding, soft nitriding, etc. may be applied.
【００１８】[0018]
【発明の効果】本発明によれば、表面硬化処理方法では
比較的簡単な部類に属する窒化処理を利用し、鋳鉄製シ
リンダと窒化処理ピストンとを組み合わせて焼け付き限
界速度を向上させたので、このクラスでは従来よりも高
速運転が可能な斜板式ポンプ又はモータを安価に提供で
きる。According to the present invention, the surface hardening treatment method uses the nitriding treatment which belongs to a relatively simple class, and the cast iron cylinder and the nitriding piston are combined to improve the burning speed limit. In this class, a swash plate type pump or motor that can operate at higher speed than before can be provided at low cost.
【図１】本発明の一実施例の斜板型ピストンモータの概
略の構成を示し、（ａ）は全体の縦断側面図、（ｂ）は
（ａ）の部分拡大図である。FIG. 1 shows a schematic configuration of a swash plate type piston motor according to an embodiment of the present invention, (a) is a vertical sectional side view of the whole, and (b) is a partially enlarged view of (a).
【図２】同実施例のタフトライド処理を施したピストン
の断面硬さ分布状態を示すグラフである。FIG. 2 is a graph showing a cross-sectional hardness distribution state of a piston that has been subjected to the tuftride treatment of the same example.
４ シリンダブロック ４ａ 孔 ４ａ 孔 ５ａ ピストン ５ｂ ピストン 4 Cylinder block 4a hole 4a hole 5a piston 5b piston
Claims (1)
くは窒化処理したシリンダブロックと、このシリンダブ
ロックに組み合わせて使用されるピストンであって、材
質が窒化可能な鋼であり、調質して素地硬度を上げたも
のに窒化処理を施し、周面の硬化した表面層のうち高硬
度層を除去して素地硬度よりも高い硬度層を残したもの
とを具備することを特徴とする斜板型ピストンポンプま
たはモータ。1. A cylinder block whose inner circumferential surface is made of cast iron or is nitrided, and a piston used in combination with the cylinder block, the material being nitridable steel, which is tempered and hardened. A swash plate type piston having a higher hardness than the base hardness by removing the high hardness layer from the hardened surface layer of the peripheral surface by nitriding Pump or motor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04337959A JP3073845B2 (en) | 1992-11-24 | 1992-11-24 | Swash plate type piston pump or motor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP04337959A JP3073845B2 (en) | 1992-11-24 | 1992-11-24 | Swash plate type piston pump or motor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06159230A true JPH06159230A (en) | 1994-06-07 |
| JP3073845B2 JP3073845B2 (en) | 2000-08-07 |
Family
ID=18313607
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP04337959A Expired - Lifetime JP3073845B2 (en) | 1992-11-24 | 1992-11-24 | Swash plate type piston pump or motor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3073845B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103306929A (en) * | 2012-03-08 | 2013-09-18 | 日立建机株式会社 | Hydraulic rotating machine and manufacturing method thereof |
| CN103306930A (en) * | 2012-03-08 | 2013-09-18 | 日立建机株式会社 | Slantwise axial type hydraulic rotary machine and method for manufacturing same |
| JP2016023353A (en) * | 2014-07-23 | 2016-02-08 | 日立建機株式会社 | Slide structure and production method for the same |
-
1992
- 1992-11-24 JP JP04337959A patent/JP3073845B2/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103306929A (en) * | 2012-03-08 | 2013-09-18 | 日立建机株式会社 | Hydraulic rotating machine and manufacturing method thereof |
| CN103306930A (en) * | 2012-03-08 | 2013-09-18 | 日立建机株式会社 | Slantwise axial type hydraulic rotary machine and method for manufacturing same |
| JP2013185520A (en) * | 2012-03-08 | 2013-09-19 | Hitachi Constr Mach Co Ltd | Liquid pressure rotary machine and method for manufacturing the same |
| JP2013185223A (en) * | 2012-03-08 | 2013-09-19 | Hitachi Constr Mach Co Ltd | Bent axis type hydraulic rotating machine and method for producing the same |
| JP2016023353A (en) * | 2014-07-23 | 2016-02-08 | 日立建機株式会社 | Slide structure and production method for the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3073845B2 (en) | 2000-08-07 |
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