EP2650538A1 - Skew plate-type hydraulic rotary machine - Google Patents
Skew plate-type hydraulic rotary machine Download PDFInfo
- Publication number
- EP2650538A1 EP2650538A1 EP10860466.1A EP10860466A EP2650538A1 EP 2650538 A1 EP2650538 A1 EP 2650538A1 EP 10860466 A EP10860466 A EP 10860466A EP 2650538 A1 EP2650538 A1 EP 2650538A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- swash plate
- cylinder block
- plain bearing
- type hydraulic
- 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.)
- Withdrawn
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01B—MACHINES OR ENGINES, IN GENERAL OR OF POSITIVE-DISPLACEMENT TYPE, e.g. STEAM ENGINES
- F01B3/00—Reciprocating-piston machines or engines with cylinder axes coaxial with, or parallel or inclined to, main shaft axis
- F01B3/10—Control of working-fluid admission or discharge peculiar thereto
- F01B3/103—Control of working-fluid admission or discharge peculiar thereto for machines with rotary cylinder block
- F01B3/108—Control of working-fluid admission or discharge peculiar thereto for machines with rotary cylinder block by turning the swash plate (with fixed inclination)
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F03—MACHINES OR ENGINES FOR LIQUIDS; WIND, SPRING, OR WEIGHT MOTORS; PRODUCING MECHANICAL POWER OR A REACTIVE PROPULSIVE THRUST, NOT OTHERWISE PROVIDED FOR
- F03C—POSITIVE-DISPLACEMENT ENGINES DRIVEN BY LIQUIDS
- F03C1/00—Reciprocating-piston liquid engines
- F03C1/02—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders
- F03C1/06—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis
- F03C1/0636—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block
- F03C1/0639—Reciprocating-piston liquid engines with multiple-cylinders, characterised by the number or arrangement of cylinders with cylinder axes generally coaxial with, or parallel or inclined to, main shaft axis having rotary cylinder block having two or more sets of cylinders or pistons
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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
- F04B1/122—Details or component parts, e.g. valves, sealings or lubrication means
- F04B1/124—Pistons
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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
- F04B1/122—Details or component parts, e.g. valves, sealings or lubrication means
- F04B1/124—Pistons
- F04B1/126—Piston shoe retaining means
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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
- F04B1/128—Driving means
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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
- F04B1/2014—Details or component parts
- F04B1/2035—Cylinder barrels
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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
- F04B1/2014—Details or component parts
- F04B1/2042—Valves
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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
- F04B1/2014—Details or component parts
- F04B1/2078—Swash plates
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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
- F04B1/2014—Details or component parts
- F04B1/2078—Swash plates
- F04B1/2085—Bearings for swash plates or driving axles
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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
- F04B1/22—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 having two or more sets of cylinders or pistons
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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
- F04B27/00—Multi-cylinder pumps specially adapted for elastic fluids and characterised by number or arrangement of cylinders
- F04B27/08—Multi-cylinder pumps specially adapted for elastic fluids and characterised by number or arrangement of cylinders having cylinders coaxial with, or parallel or inclined to, main shaft axis
- F04B27/0873—Component parts, e.g. sealings; Manufacturing or assembly thereof
- F04B27/0878—Pistons
- F04B27/0882—Pistons piston shoe retaining means
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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
- F04B27/00—Multi-cylinder pumps specially adapted for elastic fluids and characterised by number or arrangement of cylinders
- F04B27/08—Multi-cylinder pumps specially adapted for elastic fluids and characterised by number or arrangement of cylinders having cylinders coaxial with, or parallel or inclined to, main shaft axis
- F04B27/0873—Component parts, e.g. sealings; Manufacturing or assembly thereof
- F04B27/0878—Pistons
- F04B27/0886—Piston shoes
Definitions
- the present invention relates to a swash plate type hydraulic rotating machine suitably serving as, for example, a swash plate type hydraulic pump or swash plate type hydraulic motor.
- a conventional swash plate type hydraulic pump 100 includes: a cylindrical cylinder block 9 which is spline-fitted to a rotating shaft 3; a plurality of cylinders 11 formed in the cylinder block 9; pistons 13 inserted in the respective cylinders 11, such that the pistons 13 can move in a reciprocating manner; a valve plate 4 being in contact with one end of the cylinder block 9; and a keep plate 17 and a swash plate 15 facing each other, which are provided at the other end of the cylinder block 9.
- each piston 13 is formed as a spherical portion 13a protruding from the respective cylinder 11.
- Each spherical portion 13a is supported at its spherical surface by a respective one of shoes 14 which are slidingly in contact with a sliding contact surface 15c of the swash plate 15.
- the shoes 14 are fitted in respective shoe bearing holes 17a.
- the shoe bearing boles 17a are formed in the keep plate 17, corresponding to the respective cylinders 11.
- a spherical plain bearing 80 supporting the keep plate 17 is a tubular member spline-fitted to the rotating shaft 3, and is positioned between the cylinder block 9 and the swash plate 15.
- the diameter of the outer peripheral surface of the spherical plain bearing 80 gradually increases from the swash plate 15 side toward the valve plate 4 side.
- the outer peripheral surface of the spherical plain bearing 80 is in contact with the inner peripheral surface of the keep plate 17.
- Set springs 20 are provided between the spherical plain bearing 80 and the cylinder block 9. Due to the spring force of the set springs 20 and hydraulic pressure in the cylinders 11, the cylinder block 9 is pushed against the valve plate 4, so that the cylinder block 9 is in close contact with the valve plate 4, and the shoes 14 are pushed against the sliding contact surface 15c of the swash plate 15.
- the pistons 13 reciprocate within the respective cylinders 11 in accordance with the inclination of the swash plate 15.
- the swash plate type hydraulic pump utilizes the motion of the pistons 13 to suck a required amount of low-pressure working fluid and to discharge the working fluid to the high-pressure side.
- Swash plate type hydraulic motors are configured such that the rotation of the rotating shaft and the movement of the working fluid are opposite to those of the above swash plate type hydraulic pump.
- the swash plate type hydraulic pump disclosed in Patent Literature 1 is configured such that the peripheral portion of the keep plate 17 pushing the shoes 14 against the swash plate 15 has a tapered structure. Accordingly, the rigidity of the keep plate 17 is improved and deformation of the keep plate 17 is prevented, and thereby the shoes 14 are prevented from being lifted.
- Patent Literature 2 discloses an axial plunger type hydraulic system, in which the bearing surface of the shoes, the bearing surface contacting the swash plate, is formed of an aluminum-silicon alloy that is lighter than copper alloys and has excellent abrasion resistance, so that centrifugal force to be exerted on the shoes is reduced. In this manner, the shoes are prevented from being lifted from the swash plate.
- an object of the present invention is to provide a technique for preventing the shoes from being lifted from the swash plate in a swash plate type hydraulic rotating machine such as a swash plate type hydraulic pump or swash plate type hydraulic motor, and also to provide a structure capable of bearing further increase in the rotational speed of the swash plate type hydraulic rotating machine.
- a swash plate type hydraulic rotating machine includes: a rotating shaft; a valve plate and a swash plate facing each other and away from each other in an axial direction of the rotating shaft; a cylinder block fitted to an outside of the rotating shaft between the valve plate and the swash plate, such that the cylinder block is slidingly in contact with the valve plate; a plurality of cylinders provided in the cylinder block; a plurality of pistons inserted in the respective cylinders, such that the pistons are movable in the axial direction in a reciprocating manner; a plurality of shoes each connected to a distal end of a respective one of the pistons such that each shoe is movable in a rocking manner, wherein the distal end of each piston protrudes from a respective one of the cylinders toward the swash plate side; an annular keep plate loosely fitted to the rotating shaft between the swash plate and the cylinder block, the keep plate holding the shoes; a plain bearing provided between the keep plate and the cylinder block
- the gap desirably has a size of 0, or has a size of more than 0 and equal to or less than 1.2 mm.
- a swash plate type hydraulic rotating machine includes: a rotating shaft; a valve plate and a swash plate facing each other and away from each other in an axial direction of the rotating shaft; a cylinder block fitted to an outside of the rotating shaft between the valve plate and the swash plate, such that the cylinder block is slidingly in contact with the valve plate; a plurality of cylinders provided in the cylinder block; a plurality of pistons inserted in the respective cylinders, such that the pistons are movable in the axial direction in a reciprocating manner; a plurality of shoes each connected to a distal end of a respective one of the pistons such that each shoe is movable in a rocking manner, wherein the distal end of each piston protrudes from a respective one of the cylinders toward the swash plate side; an annular keep plate loosely fitted to the rotating shaft between the swash plate and the cylinder block, the keep plate holding the shoes; a plain bearing provided between the keep plate and
- the filling member may be at least one shim plate.
- a time-hardening or thermosetting filler may be provided between the filling member and one of the plain bearing and the cylinder block.
- the filling member may be a press-fit bushing.
- the gap between the cylinder block and the plain bearing is 0 or a fine gap. Accordingly, movement of the plain bearing toward the valve plate side is restricted as a result of the plain bearing contacting the cylinder block. That is, the keep plate, which pushes the shoes against the swash plate, is restricted from moving toward the valve plate side. Therefore, for example, even when the rotational speed of the rotating shaft increases and thereby inertial force that pulls the pistons toward the valve plate side, and centrifugal force moment that causes tipping of the shoes, become greater than the spring force of the set springs, the shoes do not become lifted from the swash plate or become tipped.
- the swash plate type hydraulic rotating machine according to the present invention can prevent the occurrence of, for example, decrease in operating efficiency, uneven wear of the swash plate and the shoes, galling phenomenon, and seizing, which are caused when the shoes slidingly rotate on the swash plate in a state where there is edge contact between the swash plate and the shoes. Since, as described above, the shoes do not become lifted from the swash plate even if the rotational speed of the rotating shaft is increased, the rotational speed of the rotating shaft can be further increased in the swash plate type hydraulic rotating machine.
- a swash plate type hydraulic pump 10 includes a rotating shaft 3 supported by a casing (not shown).
- the rotating shaft 3 is connected to a driving source (not shown) such as an engine.
- a cylinder block 9 having a cylindrical shape and large wall thickness is fitted to the outside of the rotating shaft 3. Specifically, splines formed at the outer periphery of the rotating shaft 3 are engaged with splines 9b formed at the inner periphery of the cylinder block 9. As a result, the cylinder block 9 rotates around the rotating shaft 3 in accordance with the rotation of the rotating shaft 3.
- a disc-shaped valve plate 4 is fixed to the casing.
- the valve plate 4 is slidingly in contact with a valve plate sliding contact surface 97, which is one end surface of the cylinder block 9.
- a pair of suction/discharge ports 5 and 6 are formed in the valve plate 4. These ports are in communication with a suction/discharge passage (not shown) formed in the casing.
- an annular swash plate 15 through which the rotating shaft 3 penetrates is provided facing the valve plate 4. The swash plate 15 and the cylinder block 9 are spaced apart from each other.
- a surface of the swash plate 15, the surface facing the cylinder block 9, is a sliding contact surface 9c on which shoes 14 slide.
- the shoes 14 will be described below.
- the swash plate 15 is inclined relative to a direction that is perpendicular to the axial direction of the rotating shaft 3 (hereinafter, simply referred to as the axial direction L).
- the swash plate 15 is configured such that the maximum tilting angle thereof can be changed by means of a tilting actuator which is not shown.
- the swash plate 15 side in the axial direction L is referred to as "the first side”
- the valve plate 4 side in the axial direction L is referred to as "the second side”.
- the first side is the opposite side to the second side.
- the cylinder block 9 integrally includes a guide portion 91 and a body 92.
- the guide portion 91 is inserted in a spherical plain bearing 80 which will be described below.
- the body 92 is provided with cylinders 11 in which pistons 13 are inserted.
- the body 92 has a diameter larger than that of the guide portion 91.
- the guide portion 91 protrudes from the body 92 toward the first side.
- the cylinder block 9 has two stepped end surfaces facing the first side.
- the end surface at the first step is a first end surface 95 positioned at the first side of the guide portion 91
- the end surface at the second step is a second end surface 96 positioned at the first side of the body 92.
- the cylinder block 9 has the aforementioned valve plate sliding contact surface 97 as an end surface facing the second side.
- a plurality of cylinders 11 (only two cylinders are shown in Fig. 1 ) are formed in the body 92 of the cylinder block 9, such that the cylinders 11 are arranged on the same circle centered on the rotating shaft 3.
- Each cylinder 11 is open toward the first side and has cylindrical space therein, the space extending in the axial direction L.
- the cylinder block 9 is provided with cylinder ports 11a through which the interiors of the cylinders 11 are in communication with the suction/discharge ports 5 and 6.
- a piston 13 is inserted such that the piston 13 can reciprocate in the axial direction L within the cylinder 11.
- a spherical portion 13a protruding from the cylinder block 9 toward the first side is formed at the first-side end of each piston 13.
- the spherical portion 13a of each piston 13 is fitted in a spherical surface support 14a formed at the second side of a respective one of the shoes 14.
- each shoe 14 is connected to the distal end of a respective one of the pistons 13 such that the shoe 14 can move in a rocking manner.
- the first side of each shoe 14 is slidingly in contact with the sliding contact surface 15c of the swash plate 15.
- each shoe 14 rotates around the rotating shaft 3 while slidingly contacting the sliding contact surface 15c of the swash plate 15.
- An annular keep plate 17 is provided between the cylinder block 9 and the swash plate 15.
- a plurality of shoe bearing holes 17a are formed in the keep plate 17, such that the shoe bearing holes 17a are provided corresponding to the respective cylinders 11.
- Each shoe 14 is fitted in a respective one of the shoe bearing holes 17a.
- the outer periphery of the shoe 14 has a smaller diameter portion 14c and a larger diameter portion 14d.
- the smaller diameter portion 14c can be fitted into the shoe bearing hole 17a.
- the larger diameter portion 14d is positioned at the first side relative to the smaller diameter portion 14c, and the larger diameter portion 14d has a diameter larger than that of the shoe bearing hole 17a.
- a stepped surface between the smaller diameter portion 14c and the larger diameter portion 14d of the shoe 14, the stepped surface facing the second side contacts a peripheral portion around the shoe bearing hole 17a. In this manner, movement of the shoe 14 toward the second side is restricted.
- the keep plate 17 is supported by the rotating shaft 3 via the spherical plain bearing 80, such that the keep plate 17 can move in a rocking manner.
- the diameter of an outer peripheral surface 81 of the spherical plain bearing 80 gradually increases toward the second side.
- the outer peripheral surface 81 is formed as a smooth curved surface.
- a flange 82 is formed at the second-side end of the outer peripheral surface 81 of the spherical plain bearing 80.
- the spherical plain bearing 80 is inserted toward the first side within the inner periphery of the keep plate 17.
- the outer peripheral surface 81 of the spherical plain bearing 80 is in contact with the inner peripheral surface 17b of the keep plate 17.
- the keep plate 17 can move in a rocking manner around the rotating shaft 3 as a result that the inner peripheral surface 17b of the keep plate 17 slides on the outer peripheral surface 81 of the spherical plain bearing 80.
- a fitting portion 83 and a guide hole 84 are formed at the inner periphery of the spherical plain bearing 80.
- the fitting portion 83 is positioned at the first side relative to the guide hole 84.
- Splines extending in the axial direction L are formed at the fitting portion 83 of the spherical plain bearing 80.
- the splines are fitted to the splines formed at the outer periphery of the rotating shaft 3.
- the spherical plain bearing 80 can integrally rotate with the rotating shaft 3 and move in the axial direction L.
- the guide hole 84 of the spherical plain bearing 80 has an opening facing the second side, and is formed as hollow space into which the above-described guide portion 91 of the cylinder block 9 can be inserted toward the first side.
- the outer periphery of the guide portion 91 of the cylinder block 9 is in contact with the inner periphery of the guide hole 84 of the spherical plain bearing 80.
- the spherical plain bearing 80 is thus guided by the guide portion 91 of the cylinder block 9, and therefore, the spherical plain bearing 80 can move in the axial direction L without wobbling.
- Set springs 20 are provided between the spherical plain bearing 80 and the cylinder block 9.
- the set springs 20 serve to bias the spherical plain bearing 80 and the cylinder block 9 toward the opposite sides in the axial direction L.
- a plurality of spring accommodating holes 93 which are open facing the first side, are formed in the body 92 of the cylinder block 9.
- a set spring 20 which is a coil spring is fitted in each spring accommodating hole 93.
- the first side of the set spring 20 protrudes from the cylinder block 9, and the protruding end of the set spring 20 is in contact with the flange 82 of the spherical plain bearing 80.
- the valve plate sliding contact surface 97 of the cylinder block 9 Due to the spring force of the set springs 20 and hydraulic pressure in the cylinders 11, the valve plate sliding contact surface 97 of the cylinder block 9 is pushed against the valve plate 4, so that the valve plate sliding contact surface 97 is in close contact with the valve plate 4. Also, the spherical plain bearing 80, which is pushed toward the first side by the spring force of the set springs 20 and the hydraulic pressure in the cylinders 11, pushes the keep plate 17 toward the first side. Further, the keep plate 17, which is pushed toward the first side, pushes the shoes 14 against the sliding contact surface 15c of the swash plate 15.
- the pistons 13 reciprocate within the respective cylinders 11 at a stroke corresponding to the maximum tilting angle of the swash plate 15.
- a suction stroke where each piston 13 moves from the top dead center to the bottom dead center, pressure oil is sucked from the suction/discharge passage into the respective cylinder 11 through the suction port 5.
- a discharge stroke where each piston 13 moves back from the bottom dead center to the top dead center, the pressure oil previously sucked into the respective cylinder 11 is discharged as high-pressure oil to the suction/discharge passage through the discharge port 6.
- the above swash plate type hydraulic pump 10 is configured such that, when in an assembled state, a gap in the axial direction L between the cylinder block 9 and the spherical plain bearing 80 is 0 or a fine gap.
- the term "assembled state” herein refers to a fully assembled state of the swash plate type hydraulic pump 10. It should be noted that the term “assembled state” does not exclude an operating state of the swash plate type hydraulic pump 10.
- the gap in the axial direction L between the cylinder block 9 and the spherical plain bearing 80 may be 0 or a fine gap when the swash plate type hydraulic pump 10 is in an operating state.
- the gap is 0
- the state where the gap in the axial direction L between the cylinder block 9 and the spherical plain bearing 80 is 0 includes: a state where the cylinder block 9 and the spherical plain bearing 80 are in contact with each other in the axial direction L; and a state where there is space G (i.e., a gap) in the axial direction L between the cylinder block 9 and the spherical plain bearing 80 and the space G is filled with a filling member F.
- space G i.e., a gap
- the spherical plain bearing 80 is unable to move toward the second side in the axial direction L since the spherical plain bearing 80 is in direct or indirect contact with the cylinder block 9.
- the gap is a fine gap
- the gap means that there is a fine gap ⁇ L in the axial direction L between the cylinder block 9 and the spherical plain bearing 80. If there is a fine gap ⁇ L in the axial direction L between the spherical plain bearing 80 and the cylinder block 9, then the spherical plain bearing 80 can move toward the second side in the axial direction L by the gap ⁇ L. However, the size of the gap ⁇ L is sufficiently small.
- the size of the gap ⁇ L is such that the amount of movement of the keep plate 17 toward the second side, which is caused when the spherical plain bearing 80 moves toward the second side, is in such a range as not to cause the shoes 14 to lose contact with the sliding contact surface 15c of the swash plate 15.
- the size of the gap ⁇ L is more than 0 and equal to or less than 1.2 mm, and more desirably, more than 0 and equal to or less than 0.8 mm.
- the gap in the axial direction L between the cylinder block 9 and the spherical plain bearing 80 is designed to be approximately 3 to 5 mm.
- the space G in the axial direction L is provided between the first end surface 95 of the cylinder block 9 and the hole bottom 85 of the guide hole 84 (i.e., the second-side end surface) of the spherical plain bearing 80.
- the space G is filled with the filling member F.
- the cylinder block 9 and the spherical plain bearing 80 are continuously arranged in the axial direction L with no vacant space therebetween, and the size of the gap in the axial direction L is 0.
- the filling member F is at least one shim plate 30. The thickness and the number of shim plates 30 are suitably selected in accordance with the size of the space G.
- the space G in the axial direction L between the cylinder block 9 and the spherical plain bearing 80 can be filled with high precision by adjusting, i.e., increasing or decreasing, the number of shim plates 30 during the assembling process.
- the swash plate type hydraulic pump 10 is configured such that when force that causes the keep plate 17 to move toward the second side occurs, the movement of the spherical plain bearing 80 toward the second side is restricted since the spherical plain bearing 80 directly or indirectly contacts the cylinder block 9, and the movement of the keep plate 17 toward the second side is restricted since the keep plate 17 contacts the spherical plain bearing 80. In this manner, the movement of the keep plate 17 toward the second side is restricted in the swash plate type hydraulic pump 10 according to the present embodiment. Therefore, even in the case described above, there is not a risk that the shoes 14 become lifted from the sliding contact surface 15c of the swash plate 15 or become tipped.
- the swash plate type hydraulic pump 10 prevents the occurrence of, for example, pump efficiency decrease, uneven wear of components such as the swash plate 15 and the shoes 14, galling phenomenon, and seizing, which are caused when the shoes 14 slidingly rotate in a state where there is edge contact between the sliding contact surface 15c of the swash plate 15 and the shoes 14.
- the set springs 20 used therein may have spring force according to conventional specifications. Accordingly, there is not a risk that increased spring force causes an increase in the friction force between the swash plate 15 and the shoes 14, which causes efficiency decrease or seizing.
- the number of components added to prevent the shoes 14 from being lifted from the sliding contact surface 15c of the swash plate 15 and to prevent the shoes 14 from tipping is small, and thus the structure is simple.
- the gap G in the axial direction L is filled with the filling member F
- the cylinder block 9 and the spherical plain bearing 80 rotate in synchronization with each other. For this reason, relative slip does not occur between the filling member F and the cylinder block 9, and between the filling member F and the spherical plain bearing 80. Accordingly, excessive friction does not occur between the cylinder block 9 and the filling member F, and between the spherical plain bearing 80 and the filling member F. Therefore, these components can bear further increase in the rotational speed of the swash plate type hydraulic pump 10.
- Fig. 3 is an enlarged longitudinal sectional view of part of the swash plate type hydraulic pump, showing an example where a gap in the axial direction is provided between the spherical plain bearing and the cylinder block.
- the swash plate type hydraulic pump 10 shown in Fig. 3 is in an assembled state where a fine gap ⁇ L in the axial direction L is provided between the cylinder block 9 and the spherical plain bearing 80.
- the first end surface 95 of the cylinder block 9 and the hole bottom 85 of the guide hole 84 of the spherical plain bearing 80 are spaced apart from each other in the axial direction L, and there is the gap ⁇ L in the axial direction L between the first end surface 95 of the cylinder block 9 and the hole bottom 85 of the guide hole 84 of the spherical plain bearing 80.
- the size of the gap ⁇ L is designed to be more than 0 and equal to or less than 1.2 mm, and more desirably, more than 0 and equal to or less than 0.8 mm when the swash plate type hydraulic pump 10 is in an assembled state.
- Fig. 4 is an enlarged longitudinal sectional view of part of the swash plate type hydraulic pump, showing Example 2 where a gap in the axial direction is provided between the spherical plain bearing and the cylinder block. In the example shown in Fig.
- the second end surface 96 of the cylinder block 9 and the flange 82 of the spherical plain bearing 80 are spaced apart from each other in the axial direction L, and there is a fine gap ⁇ L in the axial direction L between the second end surface 96 of the cylinder block 9 and the flange 82 of the spherical plain bearing 80.
- the set springs 20 are multiple disc springs provided so as to apply resilient force between the hole bottom 85 of the guide hole 84 of the spherical plain bearing 80 and the first end surface 95 of the cylinder block 9.
- Fig. 5 is an enlarged longitudinal sectional view of part of the swash plate type hydraulic pump, showing Example 2 where space in the axial direction between the spherical plain bearing and the cylinder block is filled.
- space G in the axial direction L is provided between the first end surface 95 of the cylinder block 9 and the hole bottom 85 of the guide hole 84 of the spherical plain bearing 80.
- the space G is filled with a filling ring 31.
- the filling ring 31 serves as an annular filling member F.
- An accommodating portion 32 in the shape of an annular groove is formed in the hole bottom 85 of the guide hole 84 of the spherical plain bearing 80.
- the first side of the filling ring 31 is partially embedded in the accommodating portion 32.
- the second-side end surface of the filling ring 31 is in contact with the first end surface 95 of the cylinder block 9.
- a time-hardening or thermosetting filler 33 is injected into the accommodating portion 32 of the spherical plain bearing 80, and then the filling ring 31 is fitted into the accommodating portion 32 toward the first side. Thereafter, the filler 33 is cured in a state where the filling ring 31 and the first end surface 95 of the cylinder block 9 are in contact with each other.
- the filler 33 is provided between the spherical plain bearing 80 and the filling ring 31 in the above manner, even if the size of the space G varies due to dimensional errors of components, the space G can be filled with high precision by using the filling ring 31 and the filler 33.
- the filler 33 desirably has such bonding capability as to fix the filling ring 31 to the accommodating portion 32 of the spherical plain bearing 80.
- high-strength adhesive may be applied to the outer periphery of the filling ring 31, and the filling ring 31 and the spherical plain bearing 80 may be bonded together at their contacting faces via the adhesive. In such a case, the use of the filler 33 may be eliminated.
- a press-fit bushing may be used as the filling member F.
- FIG. 6 is an enlarged longitudinal sectional view of part of the swash plate type hydraulic pump, showing Example 3 where space in the axial direction between the spherical plain bearing and the cylinder block is filled.
- space G in the axial direction L is provided between the first end surface 95 of the cylinder block 9 and the hole bottom 85 of the guide hole 84 of the spherical plain bearing 80.
- the space G is filled with a press-fit bushing 41. Accordingly, the gap in the axial direction L between the cylinder block 9 and the spherical plain bearing 80 is 0.
- the press-fit bushing 41 serves as a tubular filling member F.
- An annular groove-shaped press-fit portion 42 is formed in the hole bottom 85 of the guide hole 84 of the spherical plain bearing 80.
- the press-fit bushing 41 is press-fitted into the press-fit portion 42 toward the first side.
- the press-fit bushing 41 press-fitted into the press-fit portion 42 of the spherical plain bearing 80 cannot be removed from the press-fit portion 42 due to friction.
- the second-side end surface of the press-fit bushing 41 is in contact with the first end surface 95 of the cylinder block 9.
- the press-fit bushing 41 When the press-fit bushing 41 is used as the filling member F in the above manner, the variation in the size of the space G can be absorbed by adjusting the degree of press-fitting of the press-fit bushing 41.
- high-strength adhesive may be applied to the outer periphery of the press-fit bushing 41, and the press-fit bushing 41 and the press-fit bushing 41 may be bonded together via the adhesive.
- the press-fit bushing 41 need not be press-fitted, but may be loose-fitted.
- the position of the gap in the axial direction L between the cylinder block 9 and the spherical plain bearing 80, which gap is to be filled with the filling member F is not limited to the position between the first end surface 95 of the cylinder block 9 and the hole bottom 85 of the guide hole 84 of the spherical plain bearing 80.
- Fig. 7 is an enlarged longitudinal sectional view of part of the swash plate type hydraulic pump, showing Example 4 where space in the axial direction between the spherical plain bearing and the cylinder block is filled. In the example shown in Fig.
- space G in the axial direction L is provided between the flange 82 of the spherical plain bearing 80 and the second end surface 96 of the cylinder block 9, at which surface the spring accommodating holes 93 are open.
- the space G is filled with a filling column 35 which serves as the filling member F. Accordingly, the gap in the axial direction L between the spherical plain bearing 80 and the cylinder block 9 is 0.
- the cylinder block 9 is provided with a plurality of filling member accommodating holes 98 opening toward the swash plate 15.
- the filling column 35 is inserted in each filling member accommodating hole 98.
- the filling column 35 protrudes toward the first side from each filling member accommodating hole 98 of the cylinder block 9.
- the end surface of the protruding first side of the filling column 35 is in contact with the flange 82 of the spherical plain bearing 80.
- a time-hardening or thermosetting filler 36 is injected into the filling member accommodating holes 98 of the cylinder block 9, and then the filling column 35 is fitted into each filling member accommodating hole 98. Thereafter, the filler 36 is cured in a state where the first-side end surface of the filling column 35 and the flange 82 of the spherical plain bearing 80 are in contact with each other.
- the filler 36 When the filler 36 is provided between the cylinder block 9 and the filling column 35 in the above manner, even if the size of the space G varies due to dimensional errors of components, the space G can be filled with high precision by using the filling column 35 and the filler 36.
- the filler 36 desirably has such bonding capability as to fix the filling column 35 into the filling member accommodating hole 98 of the cylinder block 9.
- high-strength adhesive may be applied to the outer periphery of the filling column 35, and the filling column 35 and the cylinder block 9 may be bonded together via the adhesive. In such a case, the use of the filler 33 may be eliminated.
- the filling member F (filling ring 31, press-fit bushing 41, filling column 35) is used to fill the space G in the axial direction L between the cylinder block 9 and the spherical plain bearing 80.
- These filling members F may be provided either at the cylinder block 9 or at the spherical plain bearing 80.
- the above embodiment has been described by taking the swash plate type hydraulic pump as an example of a swash plate type hydraulic rotating machine.
- the swash plate type hydraulic rotating machine to which the present invention is applicable is not limited to a swash plate type hydraulic pump.
- the swash plate type hydraulic rotating machine to which the present invention is applied may be a swash plate type hydraulic motor, for example.
- the present invention is, when applied to a swash plate type hydraulic rotating machine such as a swash plate type hydraulic pump or swash plate type hydraulic motor, capable of preventing the shoes from being lifted from the swash plate even if the rotational speed of the rotating shaft is increased. Therefore, the present invention is widely applicable to swash plate type hydraulic rotating machines that include a swash plate with a variable maximum tilting angle, regardless of the structural details of such machines.
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Abstract
A swash plate type hydraulic rotating machine (10) includes: a rotating shaft (3); a valve plate (4); a swash plate (15); a cylinder block (9) fitted to the outside of the rotating shaft (3), such that the cylinder block (9) is slidingly in contact with the valve plate (4); cylinders (11) provided in the cylinder block (9); pistons (13) inserted in the respective cylinders (11), such that the pistons (13) are movable in an axial direction (L) in a reciprocating manner; shoes (14) each fitted to the distal end of a respective one of the pistons (13); an annular keep plate (17) provided between the swash plate (15) and the cylinder block (9), the keep plate (17) supporting the shoes (14); a plain bearing (80) inserted within the inner periphery of the keep plate (17), the plain bearing (80) supporting the keep plate (17) in a manner to push the keep plate (17) toward the swash plate (15) side; and set springs (20) biasing the plain bearing (80) and the cylinder block (9) toward the opposite sides in the axial direction L. The swash plate type hydraulic rotating machine (10) is configured such that, when in an assembled state, a gap in the axial direction (L) between the cylinder block (9) and the plain bearing (80) is 0 or a fine gap.
Description
- The present invention relates to a swash plate type hydraulic rotating machine suitably serving as, for example, a swash plate type hydraulic pump or swash plate type hydraulic motor.
- Conventionally, there are known swash plate type hydraulic rotating machines such as swash plate type hydraulic pumps and swash plate type hydraulic motors (see Patent Literature 1).
Fig. 8 shows a conventional swash plate type hydraulic pump. As shown inFig. 8 , a conventional swash plate typehydraulic pump 100 includes: acylindrical cylinder block 9 which is spline-fitted to a rotatingshaft 3; a plurality ofcylinders 11 formed in thecylinder block 9;pistons 13 inserted in therespective cylinders 11, such that thepistons 13 can move in a reciprocating manner; avalve plate 4 being in contact with one end of thecylinder block 9; and akeep plate 17 and aswash plate 15 facing each other, which are provided at the other end of thecylinder block 9. The distal end of eachpiston 13 is formed as aspherical portion 13a protruding from therespective cylinder 11. Eachspherical portion 13a is supported at its spherical surface by a respective one ofshoes 14 which are slidingly in contact with a slidingcontact surface 15c of theswash plate 15. Theshoes 14 are fitted in respectiveshoe bearing holes 17a. Theshoe bearing boles 17a are formed in thekeep plate 17, corresponding to therespective cylinders 11. A spherical plain bearing 80 supporting thekeep plate 17 is a tubular member spline-fitted to the rotatingshaft 3, and is positioned between thecylinder block 9 and theswash plate 15. The diameter of the outer peripheral surface of the spherical plain bearing 80 gradually increases from theswash plate 15 side toward thevalve plate 4 side. The outer peripheral surface of the spherical plain bearing 80 is in contact with the inner peripheral surface of thekeep plate 17.Set springs 20 are provided between the spherical plain bearing 80 and thecylinder block 9. Due to the spring force of theset springs 20 and hydraulic pressure in thecylinders 11, thecylinder block 9 is pushed against thevalve plate 4, so that thecylinder block 9 is in close contact with thevalve plate 4, and theshoes 14 are pushed against the slidingcontact surface 15c of theswash plate 15. - In the swash plate type hydraulic pump having the above configuration, when the
rotating shaft 3 rotates, thepistons 13 reciprocate within therespective cylinders 11 in accordance with the inclination of theswash plate 15. The swash plate type hydraulic pump utilizes the motion of thepistons 13 to suck a required amount of low-pressure working fluid and to discharge the working fluid to the high-pressure side. Swash plate type hydraulic motors are configured such that the rotation of the rotating shaft and the movement of the working fluid are opposite to those of the above swash plate type hydraulic pump. - In the above-described conventional swash plate type
hydraulic pump 100, thekeep plate 17, which is pushed toward theswash plate 15 side by the spring force of theset springs 20 and the hydraulic pressure in thecylinders 11, causes theshoes 14 to be in close contact with the slidingcontact surface 15c of theswash plate 15. However, when the rotatingshaft 3 and thecylinder block 9 rotate at high speed, the speed of the reciprocating motion of thepistons 13 within thecylinders 11 increases, which results in that thepistons 13 pull theshoes 14 toward thevalve plate 4 side with greater force. In such a high-speed rotation state, if the hydraulic pressure in thecylinders 11 decreases due to, for example, a low-pressure operation, then the force pushing theshoes 14 against theswash plate 15 depends on the spring force of theset springs 20. As a result, the pulling force of thepistons 13 pulling theshoes 14 toward thevalve plate 4 side becomes greater than the pushing force pushing theshoes 14, which pushing force is derived from theset springs 20 and the hydraulic pressure. Consequently, as shown inFig. 9 , there is a case where theshoes 14 become lifted from theswash plate 15 or become tipped (become tilted). If theshoes 14 become lifted from theswash plate 15, edge contact occurs between the slidingcontact surface 15c of theswash plate 15 and theshoes 14. If theshoes 14 in such an edge-contact state rotate while sliding on theswash plate 15, then torque loss occurs and pump efficiency decreases significantly. In addition, due to the edge contact of theshoes 14, uneven wear, galling, seizing, or the like occurs to theswash plate 15 and theshoes 14. As a result, the life of theshoes 14 and theswash plate 15 is reduced. - In order to prevent the shoes from being lifted as above, the swash plate type hydraulic pump disclosed in Patent Literature 1 is configured such that the peripheral portion of the
keep plate 17 pushing theshoes 14 against theswash plate 15 has a tapered structure. Accordingly, the rigidity of thekeep plate 17 is improved and deformation of thekeep plate 17 is prevented, and thereby theshoes 14 are prevented from being lifted. - Patent Literature 2 discloses an axial plunger type hydraulic system, in which the bearing surface of the shoes, the bearing surface contacting the swash plate, is formed of an aluminum-silicon alloy that is lighter than copper alloys and has excellent abrasion resistance, so that centrifugal force to be exerted on the shoes is reduced. In this manner, the shoes are prevented from being lifted from the swash plate.
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- PTL 1: Japanese Laid-Open Patent Application Publication No.
5-164038 - PTL 2: Japanese Laid-Open Patent Application Publication No.
50-146907 - Even though deformation of the
keep plate 17 is prevented in the conventional swash plate typehydraulic pump 100 as disclosed in Patent Literature 1, if the set springs 20 shrink, then there is a risk that thekeep plate 17 moves toward thevalve plate 4 side, resulting in that theshoes 14 become lifted from theswash plate 15. Here, one conceivable method of preventing the shoes from being lifted as above is to increase the spring force of theset springs 20 pushing thekeep plate 17 toward theswash plate 15 side. However, there is a limit of the spring force of theset springs 20. In addition, if the spring force is increased, then the friction force between theswash plate 15 and theshoes 14 increases, resulting in reduced efficiency and a risk of seizing. For these reasons, the conventional swash plate typehydraulic pump 100 cannot bear a significant increase in the rotational speed of the rotatingshaft 3. - In the axial plunger type hydraulic system disclosed in Patent Literature 2, in order to fix the position of the shoes, not a keep plate but a frame is provided at the outer peripheral portion of the swash plate. The frame serves to hold the shoes such that the shoes are kept in contact with the swash plate. When the hydraulic system having this configuration operates, relative slip occurs between the frame of the swash plate and the shoes. Therefore, the axial plunger type hydraulic system disclosed in Patent Literature 2 cannot bear a significant increase in the rotational speed.
- In view of the above, an object of the present invention is to provide a technique for preventing the shoes from being lifted from the swash plate in a swash plate type hydraulic rotating machine such as a swash plate type hydraulic pump or swash plate type hydraulic motor, and also to provide a structure capable of bearing further increase in the rotational speed of the swash plate type hydraulic rotating machine.
- A swash plate type hydraulic rotating machine according to the present invention includes: a rotating shaft; a valve plate and a swash plate facing each other and away from each other in an axial direction of the rotating shaft; a cylinder block fitted to an outside of the rotating shaft between the valve plate and the swash plate, such that the cylinder block is slidingly in contact with the valve plate; a plurality of cylinders provided in the cylinder block; a plurality of pistons inserted in the respective cylinders, such that the pistons are movable in the axial direction in a reciprocating manner; a plurality of shoes each connected to a distal end of a respective one of the pistons such that each shoe is movable in a rocking manner, wherein the distal end of each piston protrudes from a respective one of the cylinders toward the swash plate side; an annular keep plate loosely fitted to the rotating shaft between the swash plate and the cylinder block, the keep plate holding the shoes; a plain bearing provided between the keep plate and the cylinder block, the plain bearing supporting the keep plate; and spring members provided between the plain bearing and the cylinder block, the spring members biasing the plain bearing to cause the plain bearing to push the keep plate toward the swash plate side. A gap in the axial direction between the plain bearing and the cylinder block is 0 or a fine gap when the swash plate type hydraulic rotating machine is in an assembled state.
- In the above swash plate type hydraulic rotating machine, the gap desirably has a size of 0, or has a size of more than 0 and equal to or less than 1.2 mm.
- Alternatively, a swash plate type hydraulic rotating machine according to the present invention includes: a rotating shaft; a valve plate and a swash plate facing each other and away from each other in an axial direction of the rotating shaft; a cylinder block fitted to an outside of the rotating shaft between the valve plate and the swash plate, such that the cylinder block is slidingly in contact with the valve plate; a plurality of cylinders provided in the cylinder block; a plurality of pistons inserted in the respective cylinders, such that the pistons are movable in the axial direction in a reciprocating manner; a plurality of shoes each connected to a distal end of a respective one of the pistons such that each shoe is movable in a rocking manner, wherein the distal end of each piston protrudes from a respective one of the cylinders toward the swash plate side; an annular keep plate loosely fitted to the rotating shaft between the swash plate and the cylinder block, the keep plate holding the shoes; a plain bearing provided between the keep plate and the cylinder block, the plain bearing supporting the keep plate; spring members provided between the plain bearing and the cylinder block, the spring members biasing the plain bearing to cause the plain bearing to push the keep plate toward the swash plate side; and a filling member filling a gap in the axial direction between the plain bearing and the cylinder block.
- The filling member may be at least one shim plate. A time-hardening or thermosetting filler may be provided between the filling member and one of the plain bearing and the cylinder block. Alternatively, the filling member may be a press-fit bushing.
- According to the swash plate type hydraulic rotating machine having the above configuration, the gap between the cylinder block and the plain bearing is 0 or a fine gap. Accordingly, movement of the plain bearing toward the valve plate side is restricted as a result of the plain bearing contacting the cylinder block. That is, the keep plate, which pushes the shoes against the swash plate, is restricted from moving toward the valve plate side. Therefore, for example, even when the rotational speed of the rotating shaft increases and thereby inertial force that pulls the pistons toward the valve plate side, and centrifugal force moment that causes tipping of the shoes, become greater than the spring force of the set springs, the shoes do not become lifted from the swash plate or become tipped. As described above, in the swash plate type hydraulic rotating machine according to the present invention, the shoes are prevented from being lifted from the swash plate and from tipping. Therefore, the swash plate type hydraulic rotating machine according to the present invention can prevent the occurrence of, for example, decrease in operating efficiency, uneven wear of the swash plate and the shoes, galling phenomenon, and seizing, which are caused when the shoes slidingly rotate on the swash plate in a state where there is edge contact between the swash plate and the shoes.
Since, as described above, the shoes do not become lifted from the swash plate even if the rotational speed of the rotating shaft is increased, the rotational speed of the rotating shaft can be further increased in the swash plate type hydraulic rotating machine. - According to the present invention, even if inertial force that pulls the pistons toward the valve plate side, and centrifugal force moment that causes tipping of the shoes, become greater than the spring force of the set springs, the movement of the keep plate toward the valve plate side is restricted as a result of the plain bearing contacting the cylinder block. This makes it possible to prevent the shoes from being lifted from the swash plate and from tipping.
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- [
Fig. 1] Fig. 1 is a longitudinal sectional view showing a schematic configuration of a swash plate type hydraulic pump according to one embodiment of the present invention. - [
Fig. 2] Fig. 2 is an enlarged view of a portion X circled by a two-dot chain line inFig. 1 . - [
Fig. 3] Fig. 3 is an enlarged longitudinal sectional view of part of the swash plate type hydraulic pump, showing Example 1 where a gap in an axial direction is provided between a spherical plain bearing and a cylinder block. - [
Fig. 4] Fig. 4 is an enlarged longitudinal sectional view of part of the swash plate type hydraulic pump, showing Example 2 where a gap in the axial direction is provided between the spherical plain bearing and the cylinder block. - [
Fig. 5] Fig. 5 is an enlarged longitudinal sectional view of part of the swash plate type hydraulic pump, showing Example 2 where space in the axial direction between the spherical plain bearing and the cylinder block is filled. - [
Fig. 6] Fig. 6 is an enlarged longitudinal sectional view of part of the swash plate type hydraulic pump, showing Example 3 where space in the axial direction between the spherical plain bearing and the cylinder block is filled. - [
Fig. 7] Fig. 7 is an enlarged longitudinal sectional view of part of the swash plate type hydraulic pump, showing Example 4 where space in the axial direction between the spherical plain bearing and the cylinder block is filled. - [
Fig. 8] Fig. 8 is a longitudinal sectional view showing a schematic configuration of a conventional swash plate type hydraulic pump. - [
Fig. 9] Fig. 9 shows a shoe being lifted from a swash plate in the conventional swash plate type hydraulic pump. - One embodiment of the present invention is described below in detail with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same reference signs, and a repetition of the same description is avoided. Hereinafter, the description is given by taking a swash plate type hydraulic pump as an example of a swash plate type hydraulic rotating machine.
- First, a schematic configuration of the swash plate type hydraulic pump is described with reference to
Fig. 1 . A swash plate typehydraulic pump 10 includes arotating shaft 3 supported by a casing (not shown). Therotating shaft 3 is connected to a driving source (not shown) such as an engine. Acylinder block 9 having a cylindrical shape and large wall thickness is fitted to the outside of therotating shaft 3. Specifically, splines formed at the outer periphery of therotating shaft 3 are engaged with splines 9b formed at the inner periphery of thecylinder block 9. As a result, thecylinder block 9 rotates around therotating shaft 3 in accordance with the rotation of therotating shaft 3. - At one side of the cylinder block 9 (right side in
Fig. 1 ), a disc-shapedvalve plate 4 is fixed to the casing. Thevalve plate 4 is slidingly in contact with a valve plate slidingcontact surface 97, which is one end surface of thecylinder block 9. A pair of suction/discharge ports valve plate 4. These ports are in communication with a suction/discharge passage (not shown) formed in the casing. At the other side of the cylinder block 9 (left side inFig. 1 ), anannular swash plate 15 through which therotating shaft 3 penetrates is provided facing thevalve plate 4. Theswash plate 15 and thecylinder block 9 are spaced apart from each other. A surface of theswash plate 15, the surface facing thecylinder block 9, is a sliding contact surface 9c on which shoes 14 slide. Theshoes 14 will be described below. Theswash plate 15 is inclined relative to a direction that is perpendicular to the axial direction of the rotating shaft 3 (hereinafter, simply referred to as the axial direction L). Theswash plate 15 is configured such that the maximum tilting angle thereof can be changed by means of a tilting actuator which is not shown. In the description below, for the sake of convenience, theswash plate 15 side in the axial direction L is referred to as "the first side", and thevalve plate 4 side in the axial direction L is referred to as "the second side". The first side is the opposite side to the second side. - The
cylinder block 9 integrally includes aguide portion 91 and abody 92. Theguide portion 91 is inserted in a spherical plain bearing 80 which will be described below. Thebody 92 is provided withcylinders 11 in whichpistons 13 are inserted. Thebody 92 has a diameter larger than that of theguide portion 91. Theguide portion 91 protrudes from thebody 92 toward the first side. Accordingly, thecylinder block 9 has two stepped end surfaces facing the first side. The end surface at the first step is afirst end surface 95 positioned at the first side of theguide portion 91, and the end surface at the second step is asecond end surface 96 positioned at the first side of thebody 92. Thecylinder block 9 has the aforementioned valve plate slidingcontact surface 97 as an end surface facing the second side. A plurality of cylinders 11 (only two cylinders are shown inFig. 1 ) are formed in thebody 92 of thecylinder block 9, such that thecylinders 11 are arranged on the same circle centered on therotating shaft 3. Eachcylinder 11 is open toward the first side and has cylindrical space therein, the space extending in the axial direction L. Thecylinder block 9 is provided withcylinder ports 11a through which the interiors of thecylinders 11 are in communication with the suction/discharge ports cylinder 11, apiston 13 is inserted such that thepiston 13 can reciprocate in the axial direction L within thecylinder 11. Aspherical portion 13a protruding from thecylinder block 9 toward the first side is formed at the first-side end of eachpiston 13. Thespherical portion 13a of eachpiston 13 is fitted in aspherical surface support 14a formed at the second side of a respective one of theshoes 14. In this manner, eachshoe 14 is connected to the distal end of a respective one of thepistons 13 such that theshoe 14 can move in a rocking manner. The first side of eachshoe 14 is slidingly in contact with the slidingcontact surface 15c of theswash plate 15. In accordance with the rotation of therotating shaft 3, eachshoe 14 rotates around therotating shaft 3 while slidingly contacting the slidingcontact surface 15c of theswash plate 15. - An annular keep
plate 17 is provided between thecylinder block 9 and theswash plate 15. A plurality ofshoe bearing holes 17a are formed in thekeep plate 17, such that theshoe bearing holes 17a are provided corresponding to therespective cylinders 11. Eachshoe 14 is fitted in a respective one of theshoe bearing holes 17a. The outer periphery of theshoe 14 has asmaller diameter portion 14c and alarger diameter portion 14d. Thesmaller diameter portion 14c can be fitted into theshoe bearing hole 17a. Thelarger diameter portion 14d is positioned at the first side relative to thesmaller diameter portion 14c, and thelarger diameter portion 14d has a diameter larger than that of theshoe bearing hole 17a. A stepped surface between thesmaller diameter portion 14c and thelarger diameter portion 14d of theshoe 14, the stepped surface facing the second side, contacts a peripheral portion around theshoe bearing hole 17a. In this manner, movement of theshoe 14 toward the second side is restricted. - The keep
plate 17 is supported by therotating shaft 3 via the spherical plain bearing 80, such that thekeep plate 17 can move in a rocking manner. The diameter of an outerperipheral surface 81 of the spherical plain bearing 80 gradually increases toward the second side. The outerperipheral surface 81 is formed as a smooth curved surface. Aflange 82 is formed at the second-side end of the outerperipheral surface 81 of the spherical plain bearing 80. The spherical plain bearing 80 is inserted toward the first side within the inner periphery of thekeep plate 17. The outerperipheral surface 81 of the spherical plain bearing 80 is in contact with the innerperipheral surface 17b of thekeep plate 17. The keepplate 17 can move in a rocking manner around therotating shaft 3 as a result that the innerperipheral surface 17b of thekeep plate 17 slides on the outerperipheral surface 81 of the spherical plain bearing 80. Afitting portion 83 and aguide hole 84 are formed at the inner periphery of the spherical plain bearing 80. Thefitting portion 83 is positioned at the first side relative to theguide hole 84. Splines extending in the axial direction L are formed at thefitting portion 83 of the spherical plain bearing 80. The splines are fitted to the splines formed at the outer periphery of therotating shaft 3. As a result, the spherical plain bearing 80 can integrally rotate with therotating shaft 3 and move in the axial direction L. Theguide hole 84 of the spherical plain bearing 80 has an opening facing the second side, and is formed as hollow space into which the above-describedguide portion 91 of thecylinder block 9 can be inserted toward the first side. In a state where theguide portion 91 of thecylinder block 9 is inserted in theguide hole 84 of the spherical plain bearing 80, the outer periphery of theguide portion 91 of thecylinder block 9 is in contact with the inner periphery of theguide hole 84 of the spherical plain bearing 80. The spherical plain bearing 80 is thus guided by theguide portion 91 of thecylinder block 9, and therefore, the spherical plain bearing 80 can move in the axial direction L without wobbling. - Set springs 20 are provided between the spherical plain bearing 80 and the
cylinder block 9. The set springs 20 serve to bias the spherical plain bearing 80 and thecylinder block 9 toward the opposite sides in the axial direction L. Specifically, a plurality ofspring accommodating holes 93, which are open facing the first side, are formed in thebody 92 of thecylinder block 9. Aset spring 20 which is a coil spring is fitted in eachspring accommodating hole 93. The first side of theset spring 20 protrudes from thecylinder block 9, and the protruding end of theset spring 20 is in contact with theflange 82 of the spherical plain bearing 80. Due to the spring force of the set springs 20 and hydraulic pressure in thecylinders 11, the valve plate slidingcontact surface 97 of thecylinder block 9 is pushed against thevalve plate 4, so that the valve plate slidingcontact surface 97 is in close contact with thevalve plate 4. Also, the spherical plain bearing 80, which is pushed toward the first side by the spring force of the set springs 20 and the hydraulic pressure in thecylinders 11, pushes thekeep plate 17 toward the first side. Further, thekeep plate 17, which is pushed toward the first side, pushes theshoes 14 against the slidingcontact surface 15c of theswash plate 15. - Hereinafter, operations of the swash plate type
hydraulic pump 10 having the above configuration are described in relation to a case where, of the suction/discharge ports discharge port 5 is used as a suction port and the other suction/discharge port 6 is used as a discharge port. First, when a driving unit such as an engine drives therotating shaft 3 to rotate, thecylinder block 9 integrally rotates with therotating shaft 3, and the valve plate sliding contact surface 9a of thecylinder block 9 rotates while slidingly contacting thevalve plate 4. Also, theshoes 14 held by thekeep plate 17 rotate with thecylinder block 9 and thepistons 13 while slidingly contacting the slidingcontact surface 15c of theswash plate 15. As a result, thepistons 13 reciprocate within therespective cylinders 11 at a stroke corresponding to the maximum tilting angle of theswash plate 15. In a suction stroke where eachpiston 13 moves from the top dead center to the bottom dead center, pressure oil is sucked from the suction/discharge passage into therespective cylinder 11 through thesuction port 5. In a discharge stroke where eachpiston 13 moves back from the bottom dead center to the top dead center, the pressure oil previously sucked into therespective cylinder 11 is discharged as high-pressure oil to the suction/discharge passage through thedischarge port 6. When the maximum tilting angle of theswash plate 15 is adjusted by a tilting actuator (not shown), the stroke of thepistons 13 is changed, accordingly. In this manner, the discharge capacity from thecylinders 11 can be variably controlled. - The above swash plate type
hydraulic pump 10 is configured such that, when in an assembled state, a gap in the axial direction L between thecylinder block 9 and the spherical plain bearing 80 is 0 or a fine gap. The term "assembled state" herein refers to a fully assembled state of the swash plate typehydraulic pump 10. It should be noted that the term "assembled state" does not exclude an operating state of the swash plate typehydraulic pump 10. The gap in the axial direction L between thecylinder block 9 and the spherical plain bearing 80 may be 0 or a fine gap when the swash plate typehydraulic pump 10 is in an operating state. The above expression, "the gap is 0", means that the spherical plain bearing 80 and thecylinder block 9 are continuously arranged in the axial direction L and there is no vacant space therebetween. Therefore, the state where the gap in the axial direction L between thecylinder block 9 and the spherical plain bearing 80 is 0 includes: a state where thecylinder block 9 and the spherical plain bearing 80 are in contact with each other in the axial direction L; and a state where there is space G (i.e., a gap) in the axial direction L between thecylinder block 9 and the spherical plain bearing 80 and the space G is filled with a filling member F. In a case where the gap in the axial direction L between the spherical plain bearing 80 and thecylinder block 9 is 0, the spherical plain bearing 80 is unable to move toward the second side in the axial direction L since the spherical plain bearing 80 is in direct or indirect contact with thecylinder block 9. - The above expression, "the gap is a fine gap", means that there is a fine gap ΔL in the axial direction L between the
cylinder block 9 and the spherical plain bearing 80. If there is a fine gap ΔL in the axial direction L between the spherical plain bearing 80 and thecylinder block 9, then the spherical plain bearing 80 can move toward the second side in the axial direction L by the gap ΔL. However, the size of the gap ΔL is sufficiently small. The size of the gap ΔL is such that the amount of movement of thekeep plate 17 toward the second side, which is caused when the spherical plain bearing 80 moves toward the second side, is in such a range as not to cause theshoes 14 to lose contact with the slidingcontact surface 15c of theswash plate 15. Specifically, the size of the gap ΔL is more than 0 and equal to or less than 1.2 mm, and more desirably, more than 0 and equal to or less than 0.8 mm. For reference, in a conventional general swash plate type hydraulic motor, the gap in the axial direction L between thecylinder block 9 and the spherical plain bearing 80 is designed to be approximately 3 to 5 mm. - In the swash plate type
hydraulic pump 10 shown inFig. 1 andFig. 2 , the space G in the axial direction L is provided between thefirst end surface 95 of thecylinder block 9 and thehole bottom 85 of the guide hole 84 (i.e., the second-side end surface) of the spherical plain bearing 80. The space G is filled with the filling member F. Accordingly, thecylinder block 9 and the spherical plain bearing 80 are continuously arranged in the axial direction L with no vacant space therebetween, and the size of the gap in the axial direction L is 0. The filling member F is at least oneshim plate 30. The thickness and the number ofshim plates 30 are suitably selected in accordance with the size of the space G. Since theshim plates 30 are used as the filling member F, even if the size of the space G varies due to dimensional errors of components, the space G in the axial direction L between thecylinder block 9 and the spherical plain bearing 80 can be filled with high precision by adjusting, i.e., increasing or decreasing, the number ofshim plates 30 during the assembling process. - In the swash plate type
hydraulic pump 10 having the above configuration, if therotating shaft 3 rotates at high speed when the hydraulic pressure in thecylinders 11 has decreased due to, for example, a low-pressure operation, then inertial force that pulls thepistons 13 toward the second side, and centrifugal force moment that causes tipping of theshoes 14, may become greater than the spring force of the set springs 20. In this case, if thekeep plate 17 is pulled by thepistons 13 and moved toward the second side, then the pushing force of theshoes 14 against theswash plate 15 decreases, which causes tipping of theshoes 14. In this respect, the swash plate typehydraulic pump 10 according to the present embodiment is configured such that when force that causes thekeep plate 17 to move toward the second side occurs, the movement of the spherical plain bearing 80 toward the second side is restricted since the spherical plain bearing 80 directly or indirectly contacts thecylinder block 9, and the movement of thekeep plate 17 toward the second side is restricted since thekeep plate 17 contacts the spherical plain bearing 80. In this manner, the movement of thekeep plate 17 toward the second side is restricted in the swash plate typehydraulic pump 10 according to the present embodiment. Therefore, even in the case described above, there is not a risk that theshoes 14 become lifted from the slidingcontact surface 15c of theswash plate 15 or become tipped. As a result, the swash plate typehydraulic pump 10 according to the present embodiment prevents the occurrence of, for example, pump efficiency decrease, uneven wear of components such as theswash plate 15 and theshoes 14, galling phenomenon, and seizing, which are caused when theshoes 14 slidingly rotate in a state where there is edge contact between the slidingcontact surface 15c of theswash plate 15 and theshoes 14. In addition, in the swash plate typehydraulic pump 10 according to the present embodiment, the set springs 20 used therein may have spring force according to conventional specifications. Accordingly, there is not a risk that increased spring force causes an increase in the friction force between theswash plate 15 and theshoes 14, which causes efficiency decrease or seizing. Moreover, the number of components added to prevent theshoes 14 from being lifted from the slidingcontact surface 15c of theswash plate 15 and to prevent theshoes 14 from tipping is small, and thus the structure is simple. When the gap G in the axial direction L is filled with the filling member F, thecylinder block 9 and the spherical plain bearing 80 rotate in synchronization with each other. For this reason, relative slip does not occur between the filling member F and thecylinder block 9, and between the filling member F and the spherical plain bearing 80. Accordingly, excessive friction does not occur between thecylinder block 9 and the filling member F, and between the spherical plain bearing 80 and the filling member F. Therefore, these components can bear further increase in the rotational speed of the swash plate typehydraulic pump 10. - Although one preferred embodiment of the present invention is as described above, the present invention is not limited to the above-described embodiment. Various design changes may be made to the above embodiment without departing from the scope of the claims.
- For example, although the gap in the axial direction L between the
cylinder block 9 and the spherical plain bearing 80 is 0 in the swash plate typehydraulic pump 10 according to the above embodiment, the gap may alternatively be a fine gap.Fig. 3 is an enlarged longitudinal sectional view of part of the swash plate type hydraulic pump, showing an example where a gap in the axial direction is provided between the spherical plain bearing and the cylinder block. The swash plate typehydraulic pump 10 shown inFig. 3 is in an assembled state where a fine gap ΔL in the axial direction L is provided between thecylinder block 9 and the spherical plain bearing 80. To be more specific, thefirst end surface 95 of thecylinder block 9 and thehole bottom 85 of theguide hole 84 of the spherical plain bearing 80 are spaced apart from each other in the axial direction L, and there is the gap ΔL in the axial direction L between thefirst end surface 95 of thecylinder block 9 and thehole bottom 85 of theguide hole 84 of the spherical plain bearing 80. The size of the gap ΔL is designed to be more than 0 and equal to or less than 1.2 mm, and more desirably, more than 0 and equal to or less than 0.8 mm when the swash plate typehydraulic pump 10 is in an assembled state. - It should be noted that the position of the gap ΔL in the axial direction L between the
cylinder block 9 and the spherical plain bearing 80 is not limited to the position between thefirst end surface 95 of thecylinder block 9 and thehole bottom 85 of theguide hole 84 of the spherical plain bearing 80.Fig. 4 is an enlarged longitudinal sectional view of part of the swash plate type hydraulic pump, showing Example 2 where a gap in the axial direction is provided between the spherical plain bearing and the cylinder block. In the example shown inFig. 4 , thesecond end surface 96 of thecylinder block 9 and theflange 82 of the spherical plain bearing 80 are spaced apart from each other in the axial direction L, and there is a fine gap ΔL in the axial direction L between thesecond end surface 96 of thecylinder block 9 and theflange 82 of the spherical plain bearing 80. It should be noted that, in this example, the set springs 20 are multiple disc springs provided so as to apply resilient force between thehole bottom 85 of theguide hole 84 of the spherical plain bearing 80 and thefirst end surface 95 of thecylinder block 9. - As another example, although the
shim plates 30 are used as the filling member F in the swash plate typehydraulic pump 10 according to the above embodiment, the filling member F is not limited to theshim plates 30.Fig. 5 is an enlarged longitudinal sectional view of part of the swash plate type hydraulic pump, showing Example 2 where space in the axial direction between the spherical plain bearing and the cylinder block is filled. In the example shown inFig. 5 , space G in the axial direction L is provided between thefirst end surface 95 of thecylinder block 9 and thehole bottom 85 of theguide hole 84 of the spherical plain bearing 80. The space G is filled with a fillingring 31. Accordingly, the gap in the axial direction L between thecylinder block 9 and the spherical plain bearing 80 is 0. The fillingring 31 serves as an annular filling member F. Anaccommodating portion 32 in the shape of an annular groove is formed in thehole bottom 85 of theguide hole 84 of the spherical plain bearing 80. The first side of the fillingring 31 is partially embedded in theaccommodating portion 32. The second-side end surface of the fillingring 31 is in contact with thefirst end surface 95 of thecylinder block 9. At the time of assembling the swash plate typehydraulic pump 10, first, a time-hardening orthermosetting filler 33 is injected into theaccommodating portion 32 of the spherical plain bearing 80, and then the fillingring 31 is fitted into theaccommodating portion 32 toward the first side. Thereafter, thefiller 33 is cured in a state where the fillingring 31 and thefirst end surface 95 of thecylinder block 9 are in contact with each other. When thefiller 33 is provided between the spherical plain bearing 80 and the fillingring 31 in the above manner, even if the size of the space G varies due to dimensional errors of components, the space G can be filled with high precision by using the fillingring 31 and thefiller 33. It should be noted that thefiller 33 desirably has such bonding capability as to fix the fillingring 31 to theaccommodating portion 32 of the spherical plain bearing 80. Alternatively, high-strength adhesive may be applied to the outer periphery of the fillingring 31, and the fillingring 31 and the spherical plain bearing 80 may be bonded together at their contacting faces via the adhesive. In such a case, the use of thefiller 33 may be eliminated. - Further alternatively, a press-fit bushing may be used as the filling member F.
Fig. 6 is an enlarged longitudinal sectional view of part of the swash plate type hydraulic pump, showing Example 3 where space in the axial direction between the spherical plain bearing and the cylinder block is filled. In the example shown inFig. 6 , space G in the axial direction L is provided between thefirst end surface 95 of thecylinder block 9 and thehole bottom 85 of theguide hole 84 of the spherical plain bearing 80. The space G is filled with a press-fit bushing 41. Accordingly, the gap in the axial direction L between thecylinder block 9 and the spherical plain bearing 80 is 0. The press-fit bushing 41 serves as a tubular filling member F. An annular groove-shaped press-fit portion 42 is formed in thehole bottom 85 of theguide hole 84 of the spherical plain bearing 80. The press-fit bushing 41 is press-fitted into the press-fit portion 42 toward the first side. The press-fit bushing 41 press-fitted into the press-fit portion 42 of the spherical plain bearing 80 cannot be removed from the press-fit portion 42 due to friction. When the swash plate typehydraulic pump 10 is in an assembled state, the second-side end surface of the press-fit bushing 41 is in contact with thefirst end surface 95 of thecylinder block 9. When the press-fit bushing 41 is used as the filling member F in the above manner, the variation in the size of the space G can be absorbed by adjusting the degree of press-fitting of the press-fit bushing 41. Alternatively, high-strength adhesive may be applied to the outer periphery of the press-fit bushing 41, and the press-fit bushing 41 and the press-fit bushing 41 may be bonded together via the adhesive. In this case, the press-fit bushing 41 need not be press-fitted, but may be loose-fitted. - As yet another example, in the swash plate type
hydraulic pump 10 according to the above embodiment, the position of the gap in the axial direction L between thecylinder block 9 and the spherical plain bearing 80, which gap is to be filled with the filling member F, is not limited to the position between thefirst end surface 95 of thecylinder block 9 and thehole bottom 85 of theguide hole 84 of the spherical plain bearing 80.Fig. 7 is an enlarged longitudinal sectional view of part of the swash plate type hydraulic pump, showing Example 4 where space in the axial direction between the spherical plain bearing and the cylinder block is filled. In the example shown inFig. 7 , space G in the axial direction L is provided between theflange 82 of the spherical plain bearing 80 and thesecond end surface 96 of thecylinder block 9, at which surface thespring accommodating holes 93 are open. The space G is filled with a fillingcolumn 35 which serves as the filling member F. Accordingly, the gap in the axial direction L between the spherical plain bearing 80 and thecylinder block 9 is 0. Similar to thespring accommodating holes 93, thecylinder block 9 is provided with a plurality of fillingmember accommodating holes 98 opening toward theswash plate 15. The fillingcolumn 35 is inserted in each fillingmember accommodating hole 98. The fillingcolumn 35 protrudes toward the first side from each fillingmember accommodating hole 98 of thecylinder block 9. The end surface of the protruding first side of the fillingcolumn 35 is in contact with theflange 82 of the spherical plain bearing 80. At the time of assembling the swash plate typehydraulic pump 10, first, a time-hardening orthermosetting filler 36 is injected into the fillingmember accommodating holes 98 of thecylinder block 9, and then the fillingcolumn 35 is fitted into each fillingmember accommodating hole 98. Thereafter, thefiller 36 is cured in a state where the first-side end surface of the fillingcolumn 35 and theflange 82 of the spherical plain bearing 80 are in contact with each other. When thefiller 36 is provided between thecylinder block 9 and the fillingcolumn 35 in the above manner, even if the size of the space G varies due to dimensional errors of components, the space G can be filled with high precision by using the fillingcolumn 35 and thefiller 36. It should be noted that thefiller 36 desirably has such bonding capability as to fix the fillingcolumn 35 into the fillingmember accommodating hole 98 of thecylinder block 9. Alternatively, high-strength adhesive may be applied to the outer periphery of the fillingcolumn 35, and the fillingcolumn 35 and thecylinder block 9 may be bonded together via the adhesive. In such a case, the use of thefiller 33 may be eliminated. - In the above examples shown in
Figs. 5, 6 , and7 , the filling member F (fillingring 31, press-fit bushing 41, filling column 35) is used to fill the space G in the axial direction L between thecylinder block 9 and the spherical plain bearing 80. These filling members F may be provided either at thecylinder block 9 or at the spherical plain bearing 80. The above embodiment has been described by taking the swash plate type hydraulic pump as an example of a swash plate type hydraulic rotating machine. However, the swash plate type hydraulic rotating machine to which the present invention is applicable is not limited to a swash plate type hydraulic pump. The swash plate type hydraulic rotating machine to which the present invention is applied may be a swash plate type hydraulic motor, for example. - The present invention is, when applied to a swash plate type hydraulic rotating machine such as a swash plate type hydraulic pump or swash plate type hydraulic motor, capable of preventing the shoes from being lifted from the swash plate even if the rotational speed of the rotating shaft is increased. Therefore, the present invention is widely applicable to swash plate type hydraulic rotating machines that include a swash plate with a variable maximum tilting angle, regardless of the structural details of such machines.
-
- G
- space
- F
- filling member
- 3
- rotating shaft
- 4
- valve plate
- 5, 6
- suction/discharge port
- 9
- cylinder block
- 11
- cylinder
- 13
- piston
- 14
- shoe
- 15
- swash plate
- 17
- keep plate
- 20
- set spring
- 30
- shim plate
- 31
- filling ring
- 32
- accommodating portion
- 33
- filler
- 35
- filling column
- 36
- filler
- 41
- press-fit bushing
- 80
- spherical plain bearing
Claims (6)
- A swash plate type hydraulic rotating machine comprising:a rotating shaft;a valve plate and a swash plate facing each other and away from each other in an axial direction of the rotating shaft;a cylinder block fitted to an outside of the rotating shaft between the valve plate and the swash plate, such that the cylinder block is slidingly in contact with the valve plate;a plurality of cylinders provided in the cylinder block;a plurality of pistons inserted in the respective cylinders, such that the pistons are movable in the axial direction in a reciprocating manner;a plurality of shoes each connected to a distal end of a respective one of the pistons such that each shoe is movable in a rocking manner, wherein the distal end of each piston protrudes from a respective one of the cylinders toward the swash plate side;an annular keep plate loosely fitted to the rotating shaft between the swash plate and the cylinder block, the keep plate holding the shoes;a plain bearing provided between the keep plate and the cylinder block, the plain bearing supporting the keep plate; andspring members provided between the plain bearing and the cylinder block, the spring members biasing the plain bearing to cause the plain bearing to push the keep plate toward the swash plate side, whereina gap in the axial direction between the plain bearing and the cylinder block is 0 or a fine gap when the swash plate type hydraulic rotating machine is in an assembled state.
- The swash plate type hydraulic rotating machine according to claim 1, wherein the gap has a size of 0, or has a size of more than 0 and equal to or less than 1.2 mm.
- A swash plate type hydraulic rotating machine comprising:a rotating shaft;a valve plate and a swash plate facing each other and away from each other in an axial direction of the rotating shaft;a cylinder block fitted to an outside of the rotating shaft between the valve plate and the swash plate, such that the cylinder block is slidingly in contact with the valve plate;a plurality of cylinders provided in the cylinder block;a plurality of pistons inserted in the respective cylinders, such that the pistons are movable in the axial direction in a reciprocating manner;a plurality of shoes each connected to a distal end of a respective one of the pistons such that each shoe is movable in a rocking manner, wherein the distal end of each piston protrudes from a respective one of the cylinders toward the swash plate side;an annular keep plate loosely fitted to the rotating shaft between the swash plate and the cylinder block, the keep plate holding the shoes;a plain bearing provided between the keep plate and the cylinder block, the plain bearing supporting the keep plate;spring members provided between the plain bearing and the cylinder block, the spring members biasing the plain bearing to cause the plain bearing to push the keep plate toward the swash plate side; anda filling member filling a gap in the axial direction between the plain bearing and the cylinder block.
- The swash plate type hydraulic rotating machine according to claim 3, wherein the filling member is at least one shim plate.
- The swash plate type hydraulic rotating machine according to claim 3, comprising a time-hardening or thermosetting filler between the filling member and one of the plain bearing and the cylinder block.
- The swash plate type hydraulic rotating machine according to claim 3, wherein the filling member is a press-fit bushing.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/JP2010/007103 WO2012077157A1 (en) | 2010-12-07 | 2010-12-07 | Skew plate-type hydraulic rotary machine |
Publications (1)
Publication Number | Publication Date |
---|---|
EP2650538A1 true EP2650538A1 (en) | 2013-10-16 |
Family
ID=46206681
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP10860466.1A Withdrawn EP2650538A1 (en) | 2010-12-07 | 2010-12-07 | Skew plate-type hydraulic rotary machine |
Country Status (6)
Country | Link |
---|---|
US (1) | US20130327208A1 (en) |
EP (1) | EP2650538A1 (en) |
JP (1) | JPWO2012077157A1 (en) |
KR (1) | KR20130030761A (en) |
CN (1) | CN103069161A (en) |
WO (1) | WO2012077157A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9856851B2 (en) | 2013-03-29 | 2018-01-02 | Kyb Corporation | Opposed swash plate type fluid pressure rotating machine |
Families Citing this family (8)
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US10066484B2 (en) | 2013-03-29 | 2018-09-04 | Kyb Corporation | Fluid pressure rotating machine |
JP6246582B2 (en) * | 2013-12-16 | 2017-12-13 | 日立建機株式会社 | Hydraulic rotating machine |
JP6254897B2 (en) * | 2014-05-01 | 2017-12-27 | 川崎重工業株式会社 | Swash plate type hydraulic rotating machine and manufacturing method thereof |
DE102016223307A1 (en) * | 2016-11-24 | 2018-05-24 | Danfoss Power Solutions Gmbh & Co. Ohg | HYDRAULIC AXIAL PISTON UNIT WITH CENTRALLY FIXED LOW HOLDER |
CN107387351A (en) * | 2017-09-04 | 2017-11-24 | 杭州力龙液压有限公司 | Plunger assembly, plunger pump and hydraulic transmission |
CN108131266B (en) * | 2018-02-01 | 2019-08-30 | 李涌权 | Fluid pump |
CN108547748A (en) * | 2018-04-09 | 2018-09-18 | 张家港市海工船舶机械制造有限公司 | A kind of low-noise axial plunger pump |
JP2020183744A (en) * | 2019-05-09 | 2020-11-12 | ナブテスコ株式会社 | Hydraulic pump and construction machine |
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JPS5432162B2 (en) | 1974-05-16 | 1979-10-12 | ||
JPS5164038A (en) | 1974-11-27 | 1976-06-03 | Fujikura Ltd | TEEPUMAKISOCHI |
JPS54163302U (en) * | 1978-05-09 | 1979-11-15 | ||
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JPH0640940Y2 (en) * | 1986-05-19 | 1994-10-26 | 東芝機械株式会社 | Swash plate type piston pump / motor |
JPH0239578U (en) * | 1988-09-08 | 1990-03-16 | ||
JPH0373678U (en) * | 1989-11-20 | 1991-07-24 | ||
JP2977043B2 (en) * | 1990-11-28 | 1999-11-10 | 日立建機株式会社 | Swash plate type hydraulic rotary machine |
JPH07167044A (en) * | 1993-12-17 | 1995-07-04 | Uchida Yuatsu Kiki Kogyo Kk | Cylinder block engaging device for swash plate type piston pump motor |
JPH0886273A (en) * | 1994-09-19 | 1996-04-02 | Hitachi Ltd | Swash type axial piston machine |
JP3587498B2 (en) * | 1998-01-23 | 2004-11-10 | 株式会社荏原製作所 | Axial piston type pump |
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2010
- 2010-12-07 WO PCT/JP2010/007103 patent/WO2012077157A1/en active Application Filing
- 2010-12-07 CN CN2010800690030A patent/CN103069161A/en active Pending
- 2010-12-07 EP EP10860466.1A patent/EP2650538A1/en not_active Withdrawn
- 2010-12-07 KR KR1020127031763A patent/KR20130030761A/en not_active Application Discontinuation
- 2010-12-07 JP JP2012547597A patent/JPWO2012077157A1/en active Pending
- 2010-12-07 US US13/882,832 patent/US20130327208A1/en not_active Abandoned
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
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US9856851B2 (en) | 2013-03-29 | 2018-01-02 | Kyb Corporation | Opposed swash plate type fluid pressure rotating machine |
Also Published As
Publication number | Publication date |
---|---|
KR20130030761A (en) | 2013-03-27 |
WO2012077157A1 (en) | 2012-06-14 |
CN103069161A (en) | 2013-04-24 |
JPWO2012077157A1 (en) | 2014-05-19 |
US20130327208A1 (en) | 2013-12-12 |
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