EP1760313A1 - Hydraulische schrägscheiben-rotationsmaschine mit variabler verdrängung - Google Patents

Hydraulische schrägscheiben-rotationsmaschine mit variabler verdrängung Download PDF

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Publication number
EP1760313A1
EP1760313A1 EP05743472A EP05743472A EP1760313A1 EP 1760313 A1 EP1760313 A1 EP 1760313A1 EP 05743472 A EP05743472 A EP 05743472A EP 05743472 A EP05743472 A EP 05743472A EP 1760313 A1 EP1760313 A1 EP 1760313A1
Authority
EP
European Patent Office
Prior art keywords
swash plate
main
hydrostatic bearing
auxiliary
supply
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.)
Withdrawn
Application number
EP05743472A
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English (en)
French (fr)
Inventor
T. Hitachi Construction Mach. Co. Ltd. NIIDOME
Y. Hitachi Construction Mach. Co. Ltd. YABUUCHI
T. Hitachi Construction Mach. Co. Ltd. KOBAYASHI
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Construction Machinery Co Ltd
Original Assignee
Hitachi Construction Machinery Co Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Hitachi Construction Machinery Co Ltd filed Critical Hitachi Construction Machinery Co Ltd
Publication of EP1760313A1 publication Critical patent/EP1760313A1/de
Withdrawn legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B1/00—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders
    • F04B1/12—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis
    • F04B1/20—Multi-cylinder machines or pumps characterised by number or arrangement of cylinders having cylinder axes coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
    • F04B1/2092—Means for connecting rotating cylinder barrels and rotating inclined swash plates

Definitions

  • This invention relates to a swash plate type variable displacement hydraulic rotary machine suitable for use as a hydraulic pump or motor on working vehicles such as wheel loaders, wheel type hydraulic excavator or hydraulic cranes, or crawler type hydraulic excavator or cranes.
  • swash plate type variable displacement hydraulic rotary machines have been in use on working vehicles such as wheel loaders and hydraulic excavator, as a swash plate type variable displacement hydraulic pump of a hydraulic pressure source.
  • working vehicles such as wheel loaders and hydraulic excavator
  • swash plate type variable displacement hydraulic rotary machines have been resorted to as a hydraulic revolving motor or as a hydraulic vehicle drive motor.
  • a pair of supply/discharge passages are provided within the casing to supply pressure oil to and from the respective cylinders in the cylinder block.
  • hydrostatic bearings are provided between the leg portions of the swash plate and the swash plate support portions (hereinafter referred to as "the first prior art" for brevity).
  • a swash plate type variable displacement hydraulic rotary machine which is provided with first and second hydrostatic bearings independently between a pair of leg portions of a swash plate and swash plate support portions, the first hydrostatic bearing being communicated with one of supply/discharge passages which are provided in a casing, while the second hydrostatic bearing is communicated with the other one of the supply/discharge passages (e.g., as disclosed in U. S. Patent 6,048,176 ).
  • a swash plate type variable displacement hydraulic rotary machine for use in a hydraulic closed circuit type hydraulic power transmission mechanism (a hydrostatic transmission, hereinafter referred to as "HST" for brevity).
  • This swash plate type variable displacement hydraulic rotary machine is provided with a swash plate and a tilting actuator which drives the swash plate.
  • the tilting actuator is adapted to tilt the swash plate in a forward or reverse direction from a zero angle neutral position, for example, by switching a pressure oil delivery direction of a hydraulic pump from forward to reverse direction or vice versa (e.g., as disclosed in Japanese Pstent Laid-Open No. Sho 63-259182 ).
  • each leg portion of the swash plate tends to float up in a tilted state away from the swash plate support portion, letting pressure oil in the hydrostatic bearing leak to outside. As a result, the hydrostatic bearing becomes unable to maintain a lubricated state between each leg portion of the swash plate and a swash plate support portion.
  • a swash plate is tilted in forward and reverse directions from a zero angle neutral position by means of a tilting actuator.
  • the swash plate type variable displacement hydraulic pump of the third prior art suffers from the same problem even if the hydrostatic bearings of the first prior art are applied by switching a pair of supply/discharge passages from a higher pressure side to a lower pressure side or from a lower pressure side to higher pressure side corresponding to the tilted direction of the swash plate.
  • the hydraulic rotary machine of the second prior art can be applied as a hydraulic motor with a reversible rotational shaft or as a swash plate type variable displacement hydraulic pump for use in HST.
  • the rotational shaft 13 of the hydraulic pump 1 is rotationally driven by a prime mover 2, for example, by a diesel engine or the like serving as a drive source, to deliver pressure oil to a pair of main conduits 3A and 3B as shown in Fig. 1.
  • a prime mover 2 for example, by a diesel engine or the like serving as a drive source
  • the hydraulic pump 1 is connected to a hydraulic motor 5, which will be described hereinafter, to form the so-called closed hydraulic circuit 4.
  • Indicated at 5 is a vehicle drive hydraulic motor serving as a hydraulic actuator.
  • This hydraulic motor 5 is coupled, for example, with wheels 7 of a wheel type working vehicle through a reducer 6.
  • the first and second main hydrostatic bearings 22A and 22B are located closer to the through hole 21D than the first and second auxiliary hydrostatic bearings 22C and 22D.
  • the first and second main hydrostatic bearings 22A and 22B have effective bearing surface areas Sa and Sb which are broader than effective bearing surface areas Sc and Sd of the first and second auxiliary hydrostatic bearings 22C and 22D.
  • the effective bearing surface areas Sa, Sb, Sc and Sd are equivalent to pressure receiving surface areas of the bearings 22A, 22B, 22C and 22D, respectively.
  • Indicated at 24 is an oil guide passage for leading pressure oil to the first main hydrostatic bearing 22A and the first auxiliary hydrostatic bearing 22C of the hydrostatic bearing 22.
  • the oil guide passage 24 is provided between the supply/discharge passage 12A and the first main and auxiliary hydrostatic bearings 22A and 22C.
  • the oil guide passage 24 is provided in the casing 11, and composed of a common oil passage 24A which is connected at one end with the supply/discharge passage 12A and extended at the other end toward the first main and auxiliary hydrostatic bearings 22A and 22C, and two branched oil passages 24B and 24C which are branched from the other end of the common oil passage 24A.
  • One branched oil passage 24B is connected to the first main hydrostatic bearing 22A, while the other branched oil passage 24C is connected to the first auxiliary hydrostatic bearing 22C.
  • Indicated at 28 and 29 are throttles (hereinafter referred to simply as discrete throttles 28 and 29) which are provided in the course of the branched oil passages 24B and 25B, respectively, and indicated at 30 and 31 are other throttles (hereinafter referred to simply as discrete throttles 30 and 31) which are provided in the course of the branched oil passages 24C and 25C, respectively.
  • the discrete throttles 28 to 31 have a smaller throttling diameter than the common throttles 26 and 27.
  • the discrete throttle 28 finely and separately adjusts the amount of pressure oil to be supplied to the first main hydrostatic bearing 22A through the branched oil passage 24B, while the discrete throttle 29 finely and separately adjusts the amount of pressure oil to be supplied to the second main hydrostatic bearing 22B through the branched oil passage 25B.
  • the discrete throttle 30 finely and separately adjusts the amount of pressure oil to be supplied to the first auxiliary hydrostatic bearing 22C through the branched oil passage 24C, while the discrete throttle 31 finely and separately adjusts the amount of pressure oil to be supplied to the second auxiliary hydrostatic bearing 22D through the branched oil passage 25C.
  • Indicated at 41 is a conversion mechanism which converts a tilting movement of the swash plate 21 into an axial displacement by means of a cam groove 42 and a cam follower 43 as described below. More particularly, by the conversion mechanism 41, a tilting movement of the swash plate 21 is converted into an axial displacement as described later and generated a translational movement (a straight parallel movement) of a translation bar 44 in the direction of axis O-O of the rotational shaft 13.
  • the cam groove 42 is a cam groove which is provided with a cam surface for converting a tilting movement of the swash plate 21 into an axial displacement of a cam follower 43.
  • the cam groove 42 is constituted by a bent groove which is formed substantially in the shape of "V" or "U” on a lateral side of the swash plate 21 (on a lateral side of the other leg portion 21B).
  • the cam groove 42 located at a position which is spaced from the tilting center C of the swash plate 21.
  • the cam groove 42 is formed in a width which corresponds to outside diameter of the roller 43A.
  • the intermediate groove portion 42A is located at a most distant position Ra (Ra > R) from the tilting center C of the swash plate 21 along the axis O-O of the rotational shaft 13 when the swash plate 21 is in the neutral position.
  • the downwardly inclined groove portion 42B is inclined obliquely downward in a direction toward the tilting center C
  • the upwardly inclined groove portion 42C is inclined obliquely upward in a direction toward the tilting center C.
  • the roller 43A of the cam follower 43 which is in engagement with the cam groove 42 on the side of the swash plate 21 is located in an initial position of Fig. 11 together with the translation bar 44 on a line F-F perpendicularly intersecting the axis O-O of the rotational shaft 13.
  • the roller 43A of the cam follower 43 is located at a most receded position along the axis O-O of the rotational shaft 13 (in the direction of arrow E in Fig. 10).
  • the translation bar 44 is provided with the cam follower 43 at one longitudinal end and put in a translational movement together with the cam follower 43 in the direction of the axis O-O of the rotational shaft 13. Further, as shown in Figs. 3 and 4, the translation bar 44 is provided with a bifurcated anchor portion 44A at the other longitudinal end, which is adapted to grip the control sleeve 36 radially from outside.
  • the anchor portion 44A is securely fixed on the outer periphery of the control sleeve 36 by means of a plural number of set screws, rivets or other suitable fixation means.
  • the translation bar 44 is fixed to the control sleeve 36 at a predetermined angle relative to the latter (e.g., vertically at right angles), and the translation bar 44 is put in an axial displacement along the axis O-O of the rotational shaft 13 along with the roller 43A of the cam follower 43.
  • Indicated at 45 is a guide member which is provided in such a way as to cover the slot 11D of the casing 11 as shown in Fig. 3.
  • the guide member 45 is arranged to displacably and slidably support a longitudinally intermediate portion of the translation bar 44, suppressing upward and downward movements (e.g., movements in a radial direction of the cylinder block 14) as well as rattling vibrational movements of the translation bar 44. That is to say, the guide member 45 ensures smooth parallel movements (translational movements) of the translation bar 44 in the axial direction of the rotational shaft 13.
  • a control conduit 48B is provided between the inlet/outlet port 35B of the regulator 34 and a forward/reverse switch valve 51 which will be described hereinafter.
  • a tilting control pressure in the pressure chamber 32B of the tilting actuator 32 is discharged to the tank 47 through the control conduits 50B and 48B and the regulator 34, and the swash plate 21 is driven by the tilting piston 33C of the tilting actuator 33 to tilt in the direction of arrow A in Fig. 10.
  • a vehicle control valve which is provided in the side of a driver room of a wheel type vehicle as a command means. Attached to the vehicle control valve 52 is a vehicle drive pedal 52A which corresponds to an accelerator pedal of an automotive vehicle. As the vehicle drive pedal 52A is depressed by an operator of the vehicle, a pilot pressure is supplied to the hydraulic pilot portion 38 of the regulator 34 as a command signal through a command pressure conduit 53, variably adjusting the vehicle speed of the automotive vehicle in the manner as described hereinafter.
  • the swash plate type variable displacement hydraulic pump 1 operates in a vehicle driving hydraulic circuit of a wheel type working vehicle, in the manner as follows.
  • control conduit 48B is now connected to the tank 47 through the regulator 34 and the drain chamber within the casing 11 to discharge pressure oil in the pressure chamber 32B of the tilting actuator 32 to the tank 47 through the control conduits 50B and 48B and the regulator 34.
  • the swash plate 21 is driven by the piston 33C of the tilting actuator 33 in the direction of arrow A in Fig. 10.
  • the dissociative force fa of the first main hydrostatic bearing 22A and the dissociative force fc of the first auxiliary hydrostatic bearing 22C are set to satisfy conditions of the following Formula. f ⁇ 1 ⁇ fa + fc
  • the dissociative force fa of the first main hydrostatic bearing 22A acts at a position which is at a distance La from the resulting force acting point k1
  • the dissociative force fc of the first auxiliary hydrostatic bearing 22C acts at a position which is at a distance Lc from the resultant force acting point k1. Therefore, on the basis of the resultant force acting point k1, moments of the dissociative forces fa and fc are set to satisfy the relations of the following Formula.
  • the pressure oil which is drawn to the hydrostatic bearings 22A and 22C are prevented from leaking to the outside, that is to say, the leg portions 21A and 21B of the swash plate 21 as well as the tilting support surfaces 20A and 20B of the swash plate support member 20 are maintained in a lubricated state, stabilizing tilting motions of the swash plate 21 and permitting to minimize the rotational driving force of the tilting actuators 32 and 33.
  • a feedback mechanism 40 is provided between the control sleeve 36 of the regulator 34 and a lateral side of the swash plate 21.
  • this feedback mechanism 40 is arranged to make the regulator 34 follow tilting movements of the swash plate 21 when the swash plate 21 is driven to tilt either in a forward direction or in a reverse direction from the zero angle neutral position.
  • the cam groove 42 on the side of the swash plate 21 is composed of the intermediate groove portion 42A which is located at a most distant position Ra (Ra ⁇ R) from the tilting center C of the swash plate 21 along the axis O-O of the rotational shaft 13 when the swash plate 21 is in the neutral position as shown in Fig. 11, the downwardly inclined groove portion 42B which is inclined obliquely downward from the intermediate groove portion 42A in a direction toward the tilting center C, and the upwardly inclined groove portion 42C which is inclined obliquely upward from the intermediate groove portion 42A in a direction toward the tilting center C.
  • the cam groove 42 is formed as a groove which is bent in the shape of letter "V" of "U” at the position of the intermediate groove portion 42A of the lateral side of the swash plate 21.
  • the roller 43A of the cam follower 43 is restricted of movements (deviational movements) in a direction perpendicular to the axis O-O of the rotational shaft 13 and permitted of only an axial displacement along the axis O-O.
  • the roller 43A of the cam follower 43 is located in the intermediate groove portion 42A of the cam groove 42.
  • the roller 43A is moved along and in sliding contact with the downwardly inclined groove portion 42B.
  • the roller 43A is moved along and in sliding contact with the upwardly inclined groove portion 42C.
  • the discharge rate (flow rate) of pressure oil can be controlled in both forward and reverse directions by tilting the swash plate 21, a variable displacement portion, in a forward or reverse direction from a zero angle neutral position when automobile is driven in a forward direction and backward direction, and speed of the automobile can be controlled smoothly corresponding to the tilting angle of the swash plate 21.
  • the first and second main hydrostatic bearings 22A and 22B are located near the acting points k1 and k2 of the resultant force of hydraulic reaction forces which are exerted on the swash plate 21 by the pistons 16. That is to say, the dissociative forces fa and fb of the main hydrostatic bearings 22A and 22B can be close to the resultant force acting points k1 and k2.
  • the common oil passage 24A and branched oil passages 24B and 24C are provided between one supply/discharge passage 12A and the first main hydrostatic bearing 22A and the first auxiliary hydrostatic bearing 22C.
  • another common oil passage 25A and branched oil passages 25B and 25C are provided between the other supply/discharge passage 12B and the second main hydrostatic bearing 22B and the second auxiliary hydrostatic bearing 22D.
  • the common throttles 26 and 27 are provided in the course of the common oil passages 24A and 25A, respectively.
  • one oil guide passage 64 is composed of a first oil passage 64A (see Fig. 14) having one end communicated with the supply/discharge passage 12A and the other end extended toward the first main hydrostatic bearing 62A, and a second oil passage 64B, a third oil passage 64C and fourth oil passages 64D, which are bored in the swash plate 21.
  • the first main hydrostatic bearing 62A is communicated with the first auxiliary hydrostatic bearings 62C.
  • the other oil guide passage 65 is composed of a first oil passage 65A having one end communicated with the other supply/discharge passage 12B and the other end extended as far as the second main hydrostatic bearing 62B, and a second oil passage 65B, a third oil passage 65C and fourth oil passages 65D, which are bored into the swash plate 21.
  • the second oil passage 65B, third oil passage 65C and fourth oil passage 65D the second main hydrostatic bearing 62B is communicated with the auxiliary hydrostatic bearings 62D.
  • the swash plate type variable displacement hydraulic pump 1 or 61 is applied to a vehicle drive hydraulic circuit of a wheel type working vehicle like a wheel loader.
  • the present invention can be applied not only to a vehicle drive hydraulic circuit but also to other closed hydraulic circuits of various purposes, for example, to a swinging hydraulic circuit.
  • application of the present invention is not limited to a working vehicle like a wheel loader.
  • the present invention can be applied to other working vehicles such as wheel type hydraulic excavators, wheel type hydraulic cranes, bulldozers and lift trucks, or to crawler type hydraulic excavators as well.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Reciprocating Pumps (AREA)
EP05743472A 2004-06-09 2005-05-18 Hydraulische schrägscheiben-rotationsmaschine mit variabler verdrängung Withdrawn EP1760313A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2004171483A JP2005351140A (ja) 2004-06-09 2004-06-09 可変容量型斜板式液圧回転機
PCT/JP2005/009503 WO2005121554A1 (ja) 2004-06-09 2005-05-18 可変容量型斜板式液圧回転機

Publications (1)

Publication Number Publication Date
EP1760313A1 true EP1760313A1 (de) 2007-03-07

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EP05743472A Withdrawn EP1760313A1 (de) 2004-06-09 2005-05-18 Hydraulische schrägscheiben-rotationsmaschine mit variabler verdrängung

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US (1) US20070180986A1 (de)
EP (1) EP1760313A1 (de)
JP (1) JP2005351140A (de)
WO (1) WO2005121554A1 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103982387A (zh) * 2014-05-08 2014-08-13 西安交通大学 一种采用旋转窗口配油的端面凸轮驱动式向柱塞泵
EP3617501A1 (de) * 2018-08-31 2020-03-04 Nabtesco Corporation Hydrauliksystem

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5777411B2 (ja) * 2011-06-01 2015-09-09 油研工業株式会社 双方向回転型アキシャルピストンポンプ
JP6495018B2 (ja) * 2015-01-20 2019-04-03 日立建機株式会社 可変容量型斜板式油圧ポンプ
JP6206513B2 (ja) * 2016-01-14 2017-10-04 株式会社豊田自動織機 可変容量型斜板式ピストンポンプ

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2134188B (en) * 1983-01-27 1986-09-10 Linde Ag An adjustable axial piston machine of the inclined swash plate type
JPH08200208A (ja) * 1995-01-30 1996-08-06 Hitachi Constr Mach Co Ltd 斜板式ピストンポンプ・モータ装置
FR2761414B1 (fr) * 1997-02-25 2002-09-06 Linde Ag Systeme de reglage pour une unite hydrostatique volumetrique
JPH11351134A (ja) * 1998-06-12 1999-12-21 Hitachi Constr Mach Co Ltd 可変容量型斜板式油圧ポンプ
JP3778715B2 (ja) * 1999-01-11 2006-05-24 カヤバ工業株式会社 斜板式ピストンポンプ・モータ

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2005121554A1 *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103982387A (zh) * 2014-05-08 2014-08-13 西安交通大学 一种采用旋转窗口配油的端面凸轮驱动式向柱塞泵
CN103982387B (zh) * 2014-05-08 2016-03-02 西安交通大学 一种采用旋转窗口配油的端面凸轮驱动式轴向柱塞泵
EP3617501A1 (de) * 2018-08-31 2020-03-04 Nabtesco Corporation Hydrauliksystem
US11002136B2 (en) 2018-08-31 2021-05-11 Nabtesco Corporation Hydraulic system

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Publication number Publication date
WO2005121554A1 (ja) 2005-12-22
JP2005351140A (ja) 2005-12-22
US20070180986A1 (en) 2007-08-09

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