WO2021020217A1 - Hydraulic pump and hydraulic device - Google Patents

Hydraulic pump and hydraulic device Download PDF

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Publication number
WO2021020217A1
WO2021020217A1 PCT/JP2020/028150 JP2020028150W WO2021020217A1 WO 2021020217 A1 WO2021020217 A1 WO 2021020217A1 JP 2020028150 W JP2020028150 W JP 2020028150W WO 2021020217 A1 WO2021020217 A1 WO 2021020217A1
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WO
WIPO (PCT)
Prior art keywords
hydraulic
port
piston
peripheral side
hydraulic pump
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Application number
PCT/JP2020/028150
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French (fr)
Japanese (ja)
Inventor
望月　安久
愼吾 江口
Original Assignee
ヤンマーパワーテクノロジー株式会社
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Publication of WO2021020217A1 publication Critical patent/WO2021020217A1/en

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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

Definitions

  • the present invention relates to a hydraulic pump and a hydraulic device.
  • a hydraulic cylinder has a head chamber and a bottom chamber located across a piston. Since the piston rod is arranged in the head chamber, the change in the volume of the head chamber when the piston rod is displaced by a unit length is smaller than the change in the volume of the bottom chamber. Therefore, if the hydraulic cylinder and the hydraulic pump are simply connected to form a closed circuit, one of the suction amount and the discharge amount of the hydraulic pump becomes excessive and the other becomes excessive.
  • the pump is a multi-port pump having three or more ports, and some ports of this pump are connected to a tank (oil pool). A plurality of ports are arranged around the drive shaft of the pump. Then, the pump divides the sucked hydraulic oil according to the plurality of discharge side ports, and supplies an appropriate amount of the adjusted hydraulic oil to the head chamber of the hydraulic cylinder.
  • the present invention has been made in view of the above circumstances, and an object of the present invention is to reduce noise generated when hydraulic oil is supplied to a hydraulic cylinder and to improve the operational stability of the hydraulic cylinder. Is to provide a hydraulic system capable of
  • a hydraulic pump having the following configuration. That is, this hydraulic pump includes a cylinder block, a plurality of pistons, and a valve plate.
  • the cylinder block is rotatably supported, and a plurality of piston holes are provided around the center of rotation.
  • the piston is attached to each of the plurality of piston holes.
  • the valve plate switches the oil passage connected to the piston hole according to the rotation of the cylinder block.
  • a first port, a second port, and a third port are formed on the valve plate.
  • the first port is arranged in the first semicircular region when the circular region around the rotation axis of the cylinder block is divided into a first semicircular region and a second semicircular region.
  • the second port is arranged in the second semicircular region.
  • the third port is arranged on the inner peripheral side of the second port in the second semicircular region.
  • the plurality of piston holes are alternately arranged in the circumferential direction of the two virtual circles along two virtual circles having different diameters about the center of rotation.
  • the third port is located on the inner peripheral side of the second port, the port connected to the piston hole is switched due to the diversion or merging of the hydraulic oil during the discharge stroke and the suction stroke of the piston. It can be configured without. As a result, fluctuations in the discharge flow rate of hydraulic oil in the piston hole can be reduced. Therefore, the noise generated in the hydraulic device can be reduced, and the stability of the operation of the hydraulic device can be improved. Further, by utilizing the fact that the reciprocating stroke is different between the piston arranged on the outer peripheral side and the piston arranged on the inner peripheral side, it becomes easy to realize a variation in the ratio of the suction amount and the discharge amount. Therefore, the degree of freedom in designing the hydraulic system can be improved.
  • the diameter of the piston hole on the outer peripheral side and the diameter of the piston hole on the inner peripheral side are different.
  • the diameter of the piston hole arranged on the outer peripheral side is larger than the diameter of the piston hole arranged on the inner peripheral side.
  • the difference in the suction / discharge amount of hydraulic oil between the piston hole on the outer peripheral side and the piston hole on the inner peripheral side can be arbitrarily set. Can be secured. Further, by arranging a large-diameter piston hole on the outer peripheral side of the cylinder block, the space of the cylinder block can be efficiently used. As a result, the cylinder block can be miniaturized and have a high capacity.
  • this hydraulic device includes the above-mentioned hydraulic pump and a hydraulic cylinder.
  • the pressure chamber located on the side opposite to the piston rod is connected to the first port.
  • a pressure chamber located on the same side as the piston rod is connected to the second port.
  • the hydraulic system described above preferably has the following configuration. That is, this hydraulic device includes a hydraulic oil supply unit for replenishing hydraulic oil in a closed circuit formed between the hydraulic pump and the hydraulic cylinder. Of the first port, the second port, and the third port, ports other than the port connected to the hydraulic cylinder are connected to the hydraulic oil supply unit.
  • the hydraulic oil supply unit can be used as a buffer to cope with fluctuations in the amount of hydraulic oil in the closed circuit due to the difference between the discharge amount and the suction amount in the hydraulic pump.
  • ports other than the port connected to the hydraulic cylinder are operated via the inside of the casing of the hydraulic pump. It is preferably connected to the oil supply unit.
  • the hydraulic system described above preferably has the following configuration. That is, the casing of the hydraulic pump includes an oil passage member facing the valve plate.
  • the oil passage member is formed with a recess that opens on the valve plate side. When viewed along the rotation axis of the cylinder block, the opening of the recess is larger than the third port and includes the entire third port.
  • the third port is connected to the hydraulic oil supply unit via the recess.
  • the hydraulic oil supply unit is a charge circuit that pumps hydraulic oil by a charge pump.
  • the figure which shows the hydraulic circuit of the hydraulic apparatus which concerns on 1st Embodiment of this invention Partial cross-sectional perspective view of the hydraulic pump provided in the hydraulic system. The figure explaining the positional relationship of a plurality of cylinders in a hydraulic pump. The figure which looked at the valve plate in a hydraulic pump from the oil passage plate side. The cross-sectional view which shows the structure of a part of the charge circuit. The figure which shows the hydraulic circuit of the hydraulic apparatus which concerns on 2nd Embodiment of this invention. An exploded perspective sectional view showing the configuration of a valve plate and an oil passage plate. The figure which shows the modification of the valve plate.
  • FIG. 1 is a diagram showing a hydraulic circuit of the hydraulic device 1 according to the first embodiment of the present invention.
  • the hydraulic device 1 shown in FIG. 1 is applied to a machine having a hydraulic cylinder 5 (for example, a working machine).
  • a work machine examples include excavation work machines such as backhoes, ground work machines such as earth and sand lifters such as wheel loaders, and vehicles with lifting actuators such as ladder trucks.
  • the hydraulic device 1 includes a hydraulic pump 3 and a hydraulic cylinder 5.
  • the hydraulic device 1 includes a hydraulic circuit arranged between the hydraulic pump 3 and the hydraulic cylinder 5.
  • This hydraulic circuit is configured as a closed circuit that supplies the hydraulic oil discharged from the discharge side of the hydraulic pump 3 to the hydraulic cylinder 5 and returns the hydraulic oil discharged from the hydraulic cylinder 5 to the suction side of the hydraulic pump 3. Has been done.
  • the hydraulic cylinder 5 is configured as a single-rod type recovery cylinder.
  • the hydraulic cylinder 5 is formed with two pressure chambers (specifically, a bottom chamber 25 and a head chamber 27, which will be described later) located on both sides of the hydraulic cylinder 5 in the expansion / contraction direction.
  • the hydraulic pump 3 can selectively supply and discharge hydraulic oil to the two pressure chambers in order to expand and contract the hydraulic cylinder 5.
  • the hydraulic cylinder 5 includes a piston 36 and a piston rod 37.
  • the piston 36 is arranged so as to be reciprocating in the space inside the cylinder.
  • the space inside the hydraulic cylinder 5 is divided into a bottom chamber 25 and a head chamber 27 by a piston 36.
  • the piston rod 37 is fixed to the surface of the piston 36 on the head chamber 27 side, passes through the head chamber 27, and extends to the outside. Therefore, the change in the volume of the head chamber 27 when the piston 36 (piston rod 37) is displaced by a unit length is smaller than the change in the volume of the bottom chamber 25.
  • the hydraulic pump 3 is driven by the electric motor 7.
  • the hydraulic pump 3 sucks hydraulic oil from one of the two pressure chambers of the hydraulic cylinder 5, and discharges the hydraulic oil to the other pressure chamber.
  • the hydraulic pump 3 is configured as a movable swash plate type variable capacity pump. By tilting the tilt angle of the movable swash plate 11 from the neutral angle, the hydraulic pump 3 can suck and discharge hydraulic oil to extend or contract the hydraulic cylinder 5. The inclination angle of the movable swash plate 11 can be changed by operating the hydraulic servo mechanism (movable swash plate drive mechanism) 13.
  • the hydraulic pump 3 has a plurality of (3 or more) ports.
  • the hydraulic pump 3 is formed with a first port 21, a second port 22, and a third port 23.
  • the first port 21 and the second port 22 each function as a suction port or a discharge port when the hydraulic pump 3 sucks or discharges hydraulic oil to the hydraulic cylinder 5.
  • the first port 21 is connected to the bottom chamber 25 of the hydraulic cylinder 5 via the first oil passage 31.
  • the second port 22 is connected to the head chamber 27 of the hydraulic cylinder 5 via the second oil passage 32.
  • the third port 23 is connected to a charge oil passage 33 provided in a charge circuit (charge pressure supply unit) 35 as a hydraulic oil supply unit.
  • the charge circuit 35 replenishes the hydraulic circuit (closed circuit) with hydraulic oil.
  • the charge circuit 35 includes a charge oil passage 33 formed in the oil passage plate 85 described later.
  • the charge oil passage 33 is connected to the first oil passage 31 and is connected to the second oil passage 32.
  • the charge circuit 35 includes a charge pump 39.
  • the charge pump 39 is a hydraulic pump and is driven by an electric motor 48.
  • the hydraulic oil is supplied to the closed circuit in response to the loss of the hydraulic oil due to, for example, leakage of the hydraulic oil from the hydraulic pump 3.
  • the suction port of the charge pump 39 is connected to the hydraulic oil tank in which the hydraulic oil is stored.
  • the discharge port of the charge pump 39 is connected to the first oil passage 31, the second oil passage 32, and the third port 23 of the hydraulic pump 3, respectively, via the charge oil passage 33.
  • the charge circuit 35 is further connected to the hydraulic servo mechanism 13.
  • the hydraulic servo mechanism 13 changes the angle of the movable swash plate 11 by using the hydraulic pressure of the hydraulic oil supplied from the charge circuit 35. Since the configuration of the hydraulic servo mechanism 13 is known, detailed description thereof will be omitted.
  • the charge circuit 35 is provided with a charge relief valve 49.
  • the charge relief valve 49 is opened when the oil pressure of the charge circuit 35 exceeds a predetermined pressure. As a result, the pressure of the charge circuit 35 can be prevented from becoming excessive.
  • a check and relief valve 41 is arranged between the first oil passage 31 and the charge oil passage 33.
  • a check and relief valve 42 is arranged between the second oil passage 32 and the charge oil passage 33.
  • the check and relief valve 41 is opened when the pressure in the first oil passage 31 becomes lower than the pressure in the charge circuit 35. Therefore, when the hydraulic pump 3 sucks the hydraulic oil from the first oil passage 31 and the first oil passage 31 becomes low pressure, the hydraulic oil is supplied from the charge circuit 35 to the first oil passage 31. Further, the check and relief valve 41 is opened when the pressure of the first oil passage 31 exceeds a predetermined pressure. Therefore, when the pressure in the first oil passage 31 becomes excessive, the hydraulic oil in the first oil passage 31 can be released to the charge circuit 35 side.
  • the check and relief valve 42 is opened when the pressure in the second oil passage 32 becomes lower than the pressure in the charge circuit 35. Therefore, when the hydraulic pump 3 sucks the hydraulic oil from the second oil passage 32 and the second oil passage 32 becomes low pressure, the hydraulic oil is supplied from the charge circuit 35 to the second oil passage 32. Further, the check and relief valve 42 is opened when the pressure of the second oil passage 32 exceeds a predetermined pressure. Therefore, when the pressure in the second oil passage 32 becomes excessive, the hydraulic oil in the second oil passage 32 can be released to the charge circuit 35 side.
  • the check and relief valves 41 and 42 have a configuration in which the check valve and the relief valve are integrated, and the details will be described later.
  • a check valve 53 is arranged between the first port 21 and the hydraulic cylinder 5.
  • a check valve 54 is arranged between the second port 22 and the hydraulic cylinder 5.
  • the cylinder holding mechanism 51 is configured by these two check valves 53 and 54.
  • FIG. 2 is a partial cross-sectional perspective view of the hydraulic pump 3 included in the hydraulic device 1.
  • FIG. 3 is a diagram for explaining the positional relationship of the plurality of piston holes 69 in the hydraulic pump 3.
  • FIG. 4 is a view of the valve plate 67 of the hydraulic pump 3 as viewed from the oil passage plate 85 side.
  • the hydraulic pump 3 is an axial piston type hydraulic pump. As shown in FIG. 2, the hydraulic pump 3 includes a shaft 61, a cylinder block 63, a plurality of pistons 65, a valve plate 67, a movable swash plate 11, and a casing 70.
  • the shaft 61 is rotatably supported by the casing 70.
  • the shaft 61 is connected to the electric motor 7 outside the casing 70. By transmitting the driving force of the electric motor 7, the shaft 61 rotates around the axis 71 of the shaft 61.
  • the cylinder block 63 is arranged inside the casing 70.
  • the cylinder block 63 is formed in a cylindrical shape and is arranged around the shaft 61.
  • the cylinder block 63 is fixed in the middle of the shaft 61 in the longitudinal direction. Therefore, when the shaft 61 rotates, the cylinder block 63 rotates integrally with the shaft 61.
  • the rotation axis of the cylinder block 63 coincides with the axis 71 of the shaft 61.
  • a plurality of piston holes 69 are formed in the cylinder block 63.
  • Each piston hole 69 is formed in a columnar shape.
  • the centers of the plurality of piston holes 69 are assumed to be two concentric circles centered on the rotation axis. They are arranged side by side along this concentric circle.
  • five piston holes 69A are formed so as to be arranged at equal intervals along the first circle 91 having a large diameter (diameter d1), and the first circle having a small diameter (diameter d2, d2 ⁇ d1).
  • Each of the plurality of piston holes 69 is elongated in a direction parallel to the axis 71 of the shaft 61. Therefore, the plurality of piston holes 69 are oriented parallel to each other.
  • the diameters d3 of the five piston holes 69A on the outer peripheral side are the same as each other, and the diameters d4 of the five piston holes 69B on the inner peripheral side are the same as each other.
  • the diameter d3 of the piston hole 69A on the outer peripheral side is larger than the diameter d4 of the piston hole 69B on the inner peripheral side (d3> d4).
  • the phase in which the piston holes 69A on the outer peripheral side are arranged and the phase in which the piston holes 69B on the inner peripheral side are arranged appear alternately at equal angular intervals.
  • the plurality of pistons 65 have a cylindrical shape and are attached to each of the plurality of piston holes 69.
  • the outer peripheral side piston 65A is arranged in the outer peripheral side piston hole 69A
  • the inner peripheral side piston 65B is arranged in the inner peripheral side piston hole 69B.
  • the diameters of the pistons 65A and 65B correspond to the diameters of the piston holes 69A and 69B in which the pistons 65A and 65B are arranged.
  • Each of the plurality of pistons 65 can reciprocate in a direction parallel to the axis 71 of the shaft 61 while being fitted in the piston hole 69. By moving the piston 65, the hydraulic oil is sucked / discharged into the piston hole 69.
  • a retainer plate 73 for holding the shoe portion is provided at one end (shoe portion) in the direction in which each piston 65 reciprocates.
  • the retainer plate 73 is connected to a flat guide surface 74 formed on the movable swash plate 11.
  • the above-mentioned hydraulic servo mechanism 13 can adjust the inclination angle of the guide surface 74 with respect to the axis 71 of the shaft 61 by changing the angle of the movable swash plate 11.
  • the first connection hole 81 and the second connection hole 82 are formed in the cylinder block 63 in order to suck / discharge hydraulic oil to each piston hole 69.
  • the first connection hole 81 and the second connection hole 82 are open on one side in the axial direction (the side far from the movable swash plate 11) of the cylinder block 63.
  • the surface of the cylinder block 63 in which the first connection hole 81 and the second connection hole 82 are opened may be referred to as a suction / discharge surface 75.
  • the first connection hole 81 is connected to the piston hole 69A on the outer peripheral side
  • the second connection hole 82 is connected to the piston hole 69B on the inner peripheral side.
  • the first connection hole 81 and the second connection hole 82 are arranged side by side along two concentric circles around the rotation axis of the cylinder block 63 (the above-mentioned axis 71). Specifically, five first connection holes 81 are formed by arranging them at equal intervals along a large-diameter circle, and five second connection holes 82 are formed by arranging them at equal intervals along a small-diameter circle.
  • the first connection hole 81 and the second connection hole 82 are each composed of an arc-shaped hole centered on the rotation axis of the cylinder block 63.
  • the phase in which the first connection hole 81 is arranged and the phase in which the second connection hole 82 is arranged appear alternately at equal angular intervals.
  • the valve plate 67 is a plate-shaped member.
  • the valve plate 67 is fixed so as to face the oil passage plate (oil passage member) 85 provided in the casing 70. Inside the oil passage plate 85, a first oil passage 31, a second oil passage 32, a charge oil passage 33, and the like are formed.
  • the valve plate 67 is formed with a through-shaped shaft hole 62 for inserting the shaft 61.
  • the valve plate 67 is formed in a disk shape.
  • the valve plate 67 has a diameter similar to that of the cylinder block 63.
  • One surface of the valve plate 67 in the thickness direction is a contact surface 68.
  • the contact surface 68 slides into contact with the suction / discharge surface 75 of the rotating cylinder block 63.
  • the valve plate 67 has a first port 21, a second port 22, and a third port 23.
  • the first port 21, the second port 22, and the third port 23 are each provided so as to open to the above-mentioned contact surface 68.
  • the first port 21 is formed corresponding to a semicircular region (first semicircular region 67a) in which a circle corresponding to the valve plate 67 is divided in half.
  • the boundary between the two semicircular regions is a straight line perpendicular to the center of rotation of the cylinder block 63 and perpendicular to the central axis on which the movable swash plate 11 is tilted. This boundary can also be said to be the boundary at which the piston 65, which will be described later, switches between the suction stroke and the discharge stroke.
  • the first port 21 is composed of an arcuate elongated hole centered on the rotation axis of the cylinder block 63. This elongated hole is formed wider than the second port 22 and the third port 23 so that it can face any of the first connection hole 81 and the second connection hole 82 in a predetermined angle range. ..
  • the first port 21 is connected to the first oil passage 31 formed inside the oil passage plate 85.
  • the first port 21 can be connected to a plurality of piston holes 69 via the first connection hole 81 and the second connection hole 82 of the cylinder block 63.
  • the second port 22 is formed in a region (second semicircular region 67b) opposite to the side where the first port 21 is provided. Have been placed.
  • the second port 22 is composed of an arcuate elongated hole centered on the rotation axis of the cylinder block 63. This elongated hole can face the first connection hole 81 in a predetermined angle range.
  • the second port 22 is connected to the second oil passage 32 formed inside the oil passage plate 85.
  • the second port 22 can be connected to the piston hole 69A on the outer peripheral side of the plurality of piston holes 69 via the first connection hole 81 of the cylinder block 63.
  • the second port 22 since the second port 22 is located on the outer peripheral side with respect to the second connection hole 82, the second port 22 does not connect to the second connection hole 82.
  • the third port 23 is arranged in the region on the same side as the second port 22 (second semicircular region 67b) when the valve plate 67 is divided into two semicircular regions as described above.
  • the third port 23 is composed of an arcuate elongated hole centered on the rotation axis of the cylinder block 63. This elongated hole can face the second connection hole 82 in a predetermined angle range.
  • the third port 23 is arranged on the inner peripheral side of the second port 22.
  • the third port 23 is connected to the charge oil passage 33 formed in the oil passage plate 85.
  • the charge oil passage 33 is located between the first oil passage 31 and the second oil passage 32.
  • the third port 23 can be connected to the piston hole 69B on the inner peripheral side of the plurality of piston holes 69 via the second connection hole 82 of the cylinder block 63.
  • the third port 23 since the third port 23 is located on the inner peripheral side of the first connection hole 81, the third port 23 does not connect to the first connection hole 81.
  • the hydraulic pump 3 rotates the cylinder block 63 with the rotational drive of the shaft 61, whereby the plurality of pistons 65 are reciprocated so as to follow the movable swash plate 11.
  • each of the pistons 65 repeats the pumping action of suction and discharge.
  • the piston hole 69A arranged on the outer peripheral side is opened and closed with respect to the first port 21 and the second port 22 of the valve plate 67 as the cylinder block 63 rotates.
  • the piston hole 69B arranged on the inner peripheral side is opened and closed with respect to the first port 21 and the third port 23 of the valve plate 67 as the cylinder block 63 rotates.
  • the piston 65 When the movable swash plate 11 is tilted to one side from the neutral state, the piston 65 becomes a suction stroke in the piston hole 69 connected to the first port 21 of the valve plate 67, and becomes the second port 22 and the third port 23.
  • the piston 65 serves as a discharge stroke in the connected piston hole 69.
  • the hydraulic pump 3 sucks the hydraulic oil from the bottom chamber 25 of the hydraulic cylinder 5 from the first port 21 into the piston hole 69A on the outer peripheral side and the piston hole 69B on the inner peripheral side where the piston 65 is the suction stroke.
  • the hydraulic oil in the piston hole 69A on the outer peripheral side is discharged from the second port 22, and the hydraulic oil in the piston hole 69B on the inner peripheral side is discharged. It is discharged from the third port 23.
  • the hydraulic oil sucked from one port can be divided at a predetermined ratio and discharged from the two ports.
  • the hydraulic oil discharged from the second port 22 is supplied to the head chamber 27 in order to contract the hydraulic cylinder 5.
  • the hydraulic oil discharged from the third port 23 is discharged to the charge circuit 35.
  • the piston 65 When the movable swash plate 11 is tilted from the neutral state to the opposite side to the above, the piston 65 becomes the suction stroke in the piston hole 69 connected to the second port 22 and the third port 23 of the valve plate 67, and the first port The piston 65 serves as a discharge stroke in the piston hole 69 connected to the 21.
  • the hydraulic pump 3 sucks the hydraulic oil from the head chamber 27 of the hydraulic cylinder 5 from the second port 22 into the piston hole 69A on the outer peripheral side where the piston 65 is the suction stroke. Further, the hydraulic pump 3 sucks the hydraulic oil of the charge circuit 35 from the third port 23 into the piston hole 69B on the inner peripheral side where the piston 65 is the suction stroke.
  • the hydraulic oil in the piston hole 69A on the outer peripheral side and the hydraulic oil in the piston hole 69B on the inner peripheral side are both in the first port. It is discharged from 21.
  • hydraulic oil discharged from the first port 21 is supplied to the bottom chamber 25 in order to extend the hydraulic cylinder 5.
  • the hydraulic cylinder 5 can be operated by eliminating the difference between the supply amount and the discharge amount of the hydraulic oil between the bottom chamber 25 and the head chamber 27 when the hydraulic cylinder 5 is stroked.
  • 10 piston holes 69 are arranged by dividing them into 5 on the outer peripheral side and 5 on the inner peripheral side. Further, in the above-mentioned second semicircular region 67b, the piston hole 69A on the outer peripheral side is connected only to the second port 22, and the piston hole 69B on the inner peripheral side is connected only to the third port 23. Therefore, focusing on one of the piston holes 69, since the port to which the piston hole 69 is connected does not switch during the suction stroke and the discharge stroke of the piston 65, the hydraulic oil supplied and discharged from the piston hole 69 The flow rate fluctuation does not become so large. As a result, the noise generated from the hydraulic pump 3 can be reduced and the discharge pressure can be stabilized while realizing the above-mentioned diversion and merging of the hydraulic oil.
  • the hydraulic pump 3 of the present embodiment has a configuration in which 10 piston holes 69 are divided into a large-diameter first circle 91 and a small-diameter second circle 92 and arranged alternately in the circumferential direction.
  • the five piston holes 69A on the outer peripheral side and the five piston holes 69B on the inner peripheral side are arranged in a staggered manner in the circumferential direction centered on the rotation axis of the cylinder block 63.
  • the piston hole 69A on the outer peripheral side is a piston that accompanies the rotation of the cylinder block 63 as compared with the piston hole 69B on the inner peripheral side.
  • the diameter d3 of the piston hole 69A on the outer peripheral side is larger than the diameter d4 of the piston hole 69B on the inner peripheral side (d3> d4).
  • the diameters d3 and d4 may be equal to each other, but by making them different from each other, the degree of freedom in designing the suction / discharge ratio can be further increased.
  • the two piston holes 69A and 69B adjacent to each other in the circumferential direction are arranged so as to partially overlap each other in the radial direction centered on the rotation axis of the cylinder block 63.
  • a high-density arrangement of the piston holes 69 can be realized, and the cylinder block 63 can be configured compactly particularly in the radial direction. In other words, it is possible to realize a hydraulic pump 3 having a high capacity even if the size is the same.
  • the check and relief valve 41 includes a check valve body 43 and a relief valve body 44.
  • the check valve body 43 is arranged so as to be reciprocally movable in the oil hole 86 connecting the first oil passage 31 and the charge oil passage 33.
  • the check valve body 43 can open and close the oil hole 86 by moving along the oil hole 86.
  • the check and relief valve 41 is provided with a check spring 45 that urges the check valve body 43 (via the relief valve body 44 and the relief spring 46 described later) in the valve closing direction.
  • the check valve body 43 operates so as to block the flow of hydraulic oil from the first oil passage 31 to the charge oil passage 33 and allow the reverse flow.
  • the relief valve body 44 is an elongated member in the direction along the oil hole 86, and is arranged so as to be reciprocally movable in the oil hole 86.
  • One end of the relief valve body 44 in the axial direction is inserted into a relief hole 47 formed in the check valve body 43.
  • the check and relief valve 41 is provided with a relief spring 46.
  • the relief spring 46 urges the relief valve body 44 with respect to the check valve body 43 in the valve closing direction.
  • the relief valve body 44 opens. As a result, the hydraulic oil can be released from the first oil passage 31 to the charge oil passage 33 through the relief hole 47.
  • check and relief valve 42 is exactly the same as that of the check and relief valve 41 described above, so the description thereof will be omitted.
  • the hydraulic oil is sucked / discharged to the third port 23, and the hydraulic oil is supplied from the charge pump 39 to the first oil passage 31 and the second oil passage 32 via the check and relief valves 41 and 42.
  • the path for supplying the oil is configured as an oil passage (charge oil passage 33) formed in the oil passage plate 85. Therefore, since it is not necessary to provide special piping, it is possible to realize simplification and miniaturization of the configuration.
  • the hydraulic pump 3 of the present embodiment includes a cylinder block 63, a plurality of pistons 65, and a valve plate 67.
  • the cylinder block 63 is rotatably supported.
  • a plurality of piston holes 69 are formed in the cylinder block 63 around the center of rotation axis.
  • the piston 65 is attached to each of the plurality of piston holes 69.
  • the valve plate 67 switches the oil passage connected to the piston hole 69 according to the rotation of the cylinder block 63.
  • a first port 21, a second port 22, and a third port 23 are formed on the valve plate 67.
  • the first port 21 is arranged in the first semicircular region 67a when the circular region around the rotation axis of the cylinder block 63 is divided into the first semicircular region 67a and the second semicircular region 67b.
  • the second port 22 is arranged in the second semicircular region 67b.
  • the third port 23 is arranged on the inner peripheral side of the second port 22 in the second semicircular region 67b.
  • the plurality of piston holes 69 are alternately arranged in the circumferential direction of the two virtual circles 91 and 92 along the first circle 91 and the second circle 92 having different diameters about the axis 71.
  • the third port 23 is located on the inner peripheral side of the second port 22, the port connected to the piston hole 69 is divided or merged with the hydraulic oil during the discharge stroke and the suction stroke of the piston 65. Therefore, it can be configured so that it does not switch. As a result, fluctuations in the discharge flow rate of the hydraulic oil in the piston hole 69 can be reduced. Therefore, the noise generated by the hydraulic device 1 can be reduced, and the stability of the operation of the hydraulic device 1 can be improved.
  • the diameter d3 of the piston hole 69A on the outer peripheral side and the diameter d4 of the piston hole 69B on the inner peripheral side are different.
  • the difference in the suction / discharge amount of hydraulic oil due to the reciprocating stroke of the piston 65 can be freely added between the piston hole 69A on the outer peripheral side and the piston hole 69B on the inner peripheral side. Therefore, the degree of freedom in designing the ratio of the suction amount and the discharge amount of the hydraulic pump 3 can be increased.
  • the diameter d3 of the piston hole 69A on the outer peripheral side is larger than the diameter d4 of the piston hole on the inner peripheral side.
  • the suction / discharge amount of hydraulic oil between the piston hole 69A on the outer peripheral side and the piston hole 69B on the inner peripheral side The difference can be secured. Further, by arranging the large-diameter piston hole 69A on the outer peripheral side of the cylinder block 63, the space of the cylinder block 63 can be efficiently used. As a result, the cylinder block 63 can be made smaller and have a higher capacity.
  • the hydraulic device 1 of the present embodiment includes a hydraulic pump 3 and a hydraulic cylinder 5.
  • the bottom chamber 25 located on the opposite side of the piston rod 37 is connected to the first port 21 of the hydraulic pump 3.
  • the head chamber 27 located on the same side as the piston rod 37 is connected to the second port 22 of the hydraulic pump 3.
  • the hydraulic device 1 of the present embodiment includes a charge circuit 35 as a hydraulic oil supply unit for replenishing the closed circuit formed between the hydraulic pump 3 and the hydraulic cylinder 5 with hydraulic oil.
  • a charge circuit 35 as a hydraulic oil supply unit for replenishing the closed circuit formed between the hydraulic pump 3 and the hydraulic cylinder 5 with hydraulic oil.
  • the third port 23, which is not connected to the hydraulic cylinder 5, is connected to the charge circuit 35.
  • the charge circuit 35 can be used as a buffer to cope with fluctuations in the amount of hydraulic oil in the closed circuit due to the difference between the discharge amount and the suction amount in the hydraulic pump 3.
  • a charge circuit 35 for pumping hydraulic oil by a charge pump 39 is connected to the third port 23.
  • the hydraulic pump 3 when the hydraulic pump 3 sucks the hydraulic oil from the third port 23, the hydraulic pump 3 can be used to supply the hydraulic oil from the charge circuit 35 to the closed circuit. Further, when the hydraulic pump 3 discharges the hydraulic oil from the third port 23, the pressure of the charge circuit 35 is assisted, so that a small capacity charge pump 39 can be used accordingly. As a result, the cost of the charge pump 39 can be reduced.
  • FIG. 6 is a diagram showing a hydraulic device 1x according to the second embodiment.
  • FIG. 7 is an exploded perspective sectional view showing the configuration of the valve plate 67 and the oil passage plate 85.
  • the third port 23 of the hydraulic pump 3 is not the charge oil passage 33 of the charge circuit 35, but the hydraulic oil tank 102 of the hydraulic oil supply unit via the supply oil passage 101 as shown in FIG. It is connected.
  • the third port 23 of the hydraulic pump 3 sucks / discharges the hydraulic oil to the hydraulic oil tank 102.
  • the suction port of the charge pump 39 included in the charge circuit 35 is connected to the hydraulic oil tank 102.
  • the charge pump 39 is arranged side by side with the hydraulic pump 3 and is driven by the same electric motor 105 as the hydraulic pump 3.
  • a part of the supply oil passage 101 connecting the third port 23 and the hydraulic oil tank 102 is provided inside the casing 70 of the hydraulic pump 3, and the rest is provided outside.
  • a part of the supply oil passage 101 is formed inside the oil passage plate 85 provided in the casing 70, as shown in FIG.
  • a recess 107 is formed on the surface on the side where the valve plate 67 is attached.
  • the recess 107 forms an opening on the valve plate 67 side.
  • the opening of the recess 107 is larger than the arc-shaped third port 23 and has a shape including the entire third port 23.
  • the recess 107 is connected to the hydraulic oil tank 102 via the supply oil passage 101.
  • the opening of the recess 107 directly connected to the third port 23 is formed wider than the third port 23. Further, in the recess 107, the distance between the opening and the bottom surface (depth of the recess 107) is appropriately secured. Therefore, the hydraulic pump 3 can smoothly suck / discharge the hydraulic oil to the hydraulic oil tank 102 via the third port 23. Specifically, in the hydraulic pump 3, the self-priming performance at the time of sucking the hydraulic oil from the third port 23 can be improved. Further, it is possible to reduce the pressure loss when the hydraulic oil is discharged from the third port 23.
  • FIG. 8 is a diagram showing a modified example of the valve plate 67.
  • the third port 23 is formed so as to be connected to the shaft hole 62 for inserting the shaft 61.
  • the third port 23 is directly connected to the shaft hole 62, and the third port 23 and the shaft hole 62 are integrally formed to form one through hole.
  • the first port 21 is composed of a plurality of through holes 21a.
  • the plurality of through holes 21a are arranged side by side at predetermined intervals in the circumferential direction along the same circle centered on the axis 71.
  • the second port 22 is composed of a plurality of through holes 22a.
  • the plurality of through holes 22a are arranged side by side at predetermined intervals in the circumferential direction along the same circle centered on the axis 71.
  • the configuration of the ports divided in the circumferential direction in this way may be applied to only one of the first port 21 and the second port 22.
  • the third port 23 is connected to the hydraulic oil tank (hydraulic oil supply unit) 102 via the inside of the casing 70 of the hydraulic pump 3.
  • connection configuration between the third port 23 and the hydraulic oil tank 102 can be simplified.
  • the casing 70 of the hydraulic pump 3 includes an oil passage plate 85 facing the valve plate 67.
  • the oil passage plate 85 is formed with a recess 107 that opens on the valve plate 67 side.
  • the opening of the recess 107 is larger than the third port 23 and includes the entire third port 23.
  • the third port 23 is connected to the hydraulic oil tank 102 via the recess 107.
  • the flow of hydraulic oil between the hydraulic oil tank 102 and the third port 23 is smoothly formed in the oil passage plate 85 and through the wide recess 107 directly connected to the third port 23. Will be done. Therefore, in the hydraulic pump 3, the self-priming performance when the hydraulic oil is sucked from the third port 23 can be improved. Further, it is possible to reduce the pressure loss when the hydraulic oil is discharged from the third port 23.
  • the hydraulic pump 3 has three ports, but the present invention is not limited to this, and any pump 3 may have three or more ports.
  • the number of piston holes 69A and piston holes 69B can be changed arbitrarily.
  • the number of piston holes 69A on the outer peripheral side can be three
  • the number of piston holes 69B on the inner peripheral side can be three.
  • the number of piston holes 69A on the outer peripheral side can be five, and the number of piston holes 69B on the inner peripheral side can be three.
  • the two piston holes 69A on the outer peripheral side and the one piston hole on the inner peripheral side are alternately arranged in the circumferential direction of the two virtual circles.
  • the diameter d3 of the piston hole 69A on the outer peripheral side may be smaller than the diameter d4 of the piston hole 69B on the inner peripheral side (d3 ⁇ d4).
  • a hydraulic oil tank that simply stores hydraulic oil can be connected to the third port 23 of the hydraulic pump 3 instead of the charge circuit 35.
  • the charge oil passage 33 may be connected to the second port 22, and the second oil passage 32 (head chamber 27) may be connected to the third port 23.
  • the hydraulic servo mechanism 13 may be driven by a hydraulic pump different from the charge pump 39 of the charge circuit 35.
  • the discharge direction of the hydraulic pump 3 is controlled by changing the inclination direction of the movable swash plate 11, but the present invention is not limited to this.
  • the suction / discharge of the hydraulic pump 3 may be switched by switching the rotation direction of the shaft 61.
  • the tilt angle of the movable swash plate 11 may be changed by, for example, an electric motor.
  • At least one of the hydraulic pump 3 and the charge pump 39 can be configured to be driven by a drive source (for example, an engine) different from that of the electric motor.
  • a drive source for example, an engine
  • Hydraulic device Hydraulic pump 5 Hydraulic cylinder 13 Hydraulic servo mechanism (hydraulic drive mechanism) 21 1st port 22 2nd port 23 3rd port 25 Bottom chamber 27 Head chamber 35 Charge circuit (hydraulic oil supply unit) 39 Charge pump 61 Shaft 63 Cylinder block 65 Piston 67 Valve plate 67a 1st semicircular area 67b 2nd semicircular area 69 Piston hole 69A Outer peripheral side piston hole 69B Inner peripheral side piston hole 70 Casing 85 Oil passage plate (oil passage) Element) 91 1st yen (virtual circle) 92 Second Yen (Virtual Circle) 102 Hydraulic oil tank (hydraulic oil supply unit) 107 Recess d3 Diameter of piston hole on the outer circumference side d4 Diameter of piston hole on the inner circumference side

Abstract

A hydraulic pump 3 comprises a cylinder block 63 and a valve plate 67. The valve plate 67 has formed therein a first port 21, a second port 22, and a third port 23. If the circular area around the rotation axis of the cylinder block 63 is divided into a first semicircular area 67a and a second semicircular area 67b, the first port 21 is disposed in the first semicircular area 67a. The second port 22 is disposed in the second semicircular area 67b. The third port 23 is disposed more peripherally inward than the second port 22 in the second semicircular area 67b. In the cylinder block 63, a plurality of piston holes 69 are disposed along two virtual circles having mutually different diameters that are centered on the axial center 71, the piston holes being arranged alternately in the circumferential direction of the two virtual circles.

Description

油圧ポンプ及び油圧装置Hydraulic pump and hydraulic system
　本発明は、油圧ポンプ及び油圧装置に関する。 The present invention relates to a hydraulic pump and a hydraulic device.
　従来から、油圧ポンプから吐出される作動油を油圧シリンダに供給し、かつ、この油圧シリンダから排出される作動油を油圧ポンプの吸入側に戻す閉回路を構成する油圧装置が知られている。この種の油圧装置は、例えば特許文献１及び２に開示されている。 Conventionally, a hydraulic device having a closed circuit for supplying hydraulic oil discharged from a hydraulic pump to a hydraulic cylinder and returning the hydraulic oil discharged from the hydraulic cylinder to the suction side of the hydraulic pump has been known. This type of hydraulic system is disclosed in, for example, Patent Documents 1 and 2.
　油圧シリンダを有する作業機では、油圧シリンダへ高圧の作動油を油圧装置により供給する場合、油圧回路が開回路であると、油圧バルブを介する損失の発生が避けられず、低燃費を実現することが難しい。特許文献１及び２の油圧装置のように閉回路を構成することで、油圧バルブを不要とすることができる。 In a work machine having a hydraulic cylinder, when high-pressure hydraulic oil is supplied to the hydraulic cylinder by a hydraulic device, if the hydraulic circuit is open, loss through the hydraulic valve is unavoidable, and low fuel consumption is realized. Is difficult. By configuring a closed circuit as in the hydraulic devices of Patent Documents 1 and 2, the hydraulic valve can be eliminated.
　一般的に、油圧シリンダは、ピストンを挟んで位置するヘッド室及びボトム室を有する。ヘッド室にはピストンロッドが配置されているので、ピストンロッドが単位長さだけ変位する場合のヘッド室の容積の変化は、ボトム室の容積の変化よりも小さい。そのため、油圧シリンダと油圧ポンプとを単純に接続して閉回路を構成するだけでは、油圧ポンプの吸入量及び吐出量のうち一方が過多となり、他方が過少となってしまう。 Generally, a hydraulic cylinder has a head chamber and a bottom chamber located across a piston. Since the piston rod is arranged in the head chamber, the change in the volume of the head chamber when the piston rod is displaced by a unit length is smaller than the change in the volume of the bottom chamber. Therefore, if the hydraulic cylinder and the hydraulic pump are simply connected to form a closed circuit, one of the suction amount and the discharge amount of the hydraulic pump becomes excessive and the other becomes excessive.
　この点、特許文献１及び２が開示する構成では、ポンプは３以上の複数のポートを有する複数ポートポンプとし、このポンプの一部のポートをタンク（油溜まり）に接続している。複数のポートは、ポンプの駆動軸まわりに配置されている。そして、ポンプが、吸入した作動油を複数の吐出側のポートに合わせて分け、調節された適宜の量の作動油を油圧シリンダのヘッド室に供給する。 In this regard, in the configuration disclosed in Patent Documents 1 and 2, the pump is a multi-port pump having three or more ports, and some ports of this pump are connected to a tank (oil pool). A plurality of ports are arranged around the drive shaft of the pump. Then, the pump divides the sucked hydraulic oil according to the plurality of discharge side ports, and supplies an appropriate amount of the adjusted hydraulic oil to the head chamber of the hydraulic cylinder.
特開平１０－１６９５４７号公報Japanese Unexamined Patent Publication No. 10-169547 特許第５３４２９４９号公報Japanese Patent No. 5342949
　しかし、特許文献１及び２の構成では、作動油の量を調節するために作動油を複数の吐出側のポートに合わせて分けるとき、油圧ポンプを構成するピストンが端から端まで移動する途中でポートの切換が生じるため、作動油の吐出流量の変動が大きくなる。この変動により、油圧装置に関して、特に高負荷時に振動を伴う騒音が大きくなるとともに、油圧シリンダの作動も不安定になる。 However, in the configurations of Patent Documents 1 and 2, when the hydraulic oil is divided according to a plurality of discharge side ports in order to adjust the amount of the hydraulic oil, the piston constituting the hydraulic pump is in the process of moving from end to end. Since the port is switched, the fluctuation of the discharge flow rate of the hydraulic oil becomes large. Due to this fluctuation, the noise accompanied by vibration of the hydraulic device becomes large, especially when the load is high, and the operation of the hydraulic cylinder becomes unstable.
　本発明は以上の事情に鑑みてされたものであり、その目的は、油圧シリンダへの作動油の供給時に発生する騒音を低減することができるとともに、油圧シリンダの作動の安定性を向上させることができる油圧装置を提供することにある。 The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce noise generated when hydraulic oil is supplied to a hydraulic cylinder and to improve the operational stability of the hydraulic cylinder. Is to provide a hydraulic system capable of
課題を解決するための手段及び効果Means and effects to solve problems
　本発明の解決しようとする課題は以上の如くであり、次にこの課題を解決するための手段とその効果を説明する。 The problem to be solved by the present invention is as described above, and next, the means for solving this problem and its effect will be described.
　本発明の第１の観点によれば、以下の構成の油圧ポンプが提供される。即ち、この油圧ポンプは、シリンダブロックと、複数のピストンと、バルブプレートと、を備える。前記シリンダブロックは、回転可能に支持され、複数のピストン穴が回転軸心まわりに設けられる。前記ピストンは、前記複数のピストン穴のそれぞれに取り付けられる。前記バルブプレートは、前記ピストン穴に接続される油路を前記シリンダブロックの回転に応じて切り換える。前記バルブプレートには、第１ポートと、第２ポートと、第３ポートと、が形成される。前記第１ポートは、前記シリンダブロックの回転軸心の周囲の円形の領域を第１半円領域と第２半円領域に分けたときに、前記第１半円領域に配置される。前記第２ポートは、前記第２半円領域に配置される。前記第３ポートは、前記第２半円領域において前記第２ポートよりも内周側に配置される。前記複数のピストン穴は、前記回転軸心を中心とした互いに異なる径の２つの仮想円に沿って、当該２つの仮想円の周方向に交互に配置されている。 According to the first aspect of the present invention, a hydraulic pump having the following configuration is provided. That is, this hydraulic pump includes a cylinder block, a plurality of pistons, and a valve plate. The cylinder block is rotatably supported, and a plurality of piston holes are provided around the center of rotation. The piston is attached to each of the plurality of piston holes. The valve plate switches the oil passage connected to the piston hole according to the rotation of the cylinder block. A first port, a second port, and a third port are formed on the valve plate. The first port is arranged in the first semicircular region when the circular region around the rotation axis of the cylinder block is divided into a first semicircular region and a second semicircular region. The second port is arranged in the second semicircular region. The third port is arranged on the inner peripheral side of the second port in the second semicircular region. The plurality of piston holes are alternately arranged in the circumferential direction of the two virtual circles along two virtual circles having different diameters about the center of rotation.
　これにより、吸入量と吐出量が不等な油圧ポンプを実現することができる。また、第３ポートが第２ポートの内周側に位置することから、ピストンの吐出行程の途中及び吸入行程の途中では、ピストン穴に接続するポートが作動油の分流又は合流のために切り換わらない構成とすることができる。これにより、ピストン穴における作動油の吐出流量の変動を低減することができる。従って、油圧装置で発生する騒音を低減することができるとともに、油圧装置の作動に関する安定性を向上させることができる。また、外周側に配置されるピストンと内周側に配置されるピストンとで往復ストロークが異なることを利用して、吸入量と吐出量の比のバリエーションを実現し易くなる。従って、油圧装置の設計の自由度を向上させることができる。 This makes it possible to realize a hydraulic pump in which the suction amount and the discharge amount are unequal. Further, since the third port is located on the inner peripheral side of the second port, the port connected to the piston hole is switched due to the diversion or merging of the hydraulic oil during the discharge stroke and the suction stroke of the piston. It can be configured without. As a result, fluctuations in the discharge flow rate of hydraulic oil in the piston hole can be reduced. Therefore, the noise generated in the hydraulic device can be reduced, and the stability of the operation of the hydraulic device can be improved. Further, by utilizing the fact that the reciprocating stroke is different between the piston arranged on the outer peripheral side and the piston arranged on the inner peripheral side, it becomes easy to realize a variation in the ratio of the suction amount and the discharge amount. Therefore, the degree of freedom in designing the hydraulic system can be improved.
　前記の油圧ポンプにおいては、外周側の前記ピストン穴の直径と、内周側の前記ピストン穴の直径と、が異なることが好ましい。 In the hydraulic pump, it is preferable that the diameter of the piston hole on the outer peripheral side and the diameter of the piston hole on the inner peripheral side are different.
　これにより、外周側のピストン穴と内周側のピストン穴との間で、ピストンの往復運動による作動油の吸入・吐出量の差を自由に付けることができる。従って、油圧ポンプの吸入量と吐出量の比の設計の自由度を、より高くすることができる。 As a result, it is possible to freely make a difference in the suction / discharge amount of hydraulic oil due to the reciprocating motion of the piston between the piston hole on the outer peripheral side and the piston hole on the inner peripheral side. Therefore, the degree of freedom in designing the ratio of the suction amount and the discharge amount of the hydraulic pump can be increased.
　前記の油圧ポンプにおいては、外周側に配置される前記ピストン穴の直径が、内周側に配置される前記ピストン穴の直径よりも大きいことが好ましい。 In the hydraulic pump, it is preferable that the diameter of the piston hole arranged on the outer peripheral side is larger than the diameter of the piston hole arranged on the inner peripheral side.
　これにより、ピストンの往復ストロークの差とピストン穴の直径の差の相乗効果により、外周側のピストン穴と内周側のピストン穴との間で、作動油の吸入・吐出量の差を任意に確保することができる。また、シリンダブロックにおいて外周側に大径のピストン穴を配置することで、シリンダブロックのスペースを効率的に利用することができる。この結果、シリンダブロックの小型化及び高容量化を実現できる。 As a result, due to the synergistic effect of the difference in the reciprocating stroke of the piston and the difference in the diameter of the piston hole, the difference in the suction / discharge amount of hydraulic oil between the piston hole on the outer peripheral side and the piston hole on the inner peripheral side can be arbitrarily set. Can be secured. Further, by arranging a large-diameter piston hole on the outer peripheral side of the cylinder block, the space of the cylinder block can be efficiently used. As a result, the cylinder block can be miniaturized and have a high capacity.
　本発明の第２の観点によれば、以下の構成の油圧装置が提供される。即ち、この油圧装置は、前記の油圧ポンプと、油圧シリンダと、を備える。前記油圧シリンダにおいてピストンにより区画される圧力室のうち、前記ピストンロッドと反対側に位置する圧力室が、前記第１ポートに接続される。前記ピストンロッドと同じ側に位置する圧力室が、前記第２ポートに接続される。 According to the second aspect of the present invention, a hydraulic system having the following configuration is provided. That is, this hydraulic device includes the above-mentioned hydraulic pump and a hydraulic cylinder. Of the pressure chambers partitioned by the piston in the hydraulic cylinder, the pressure chamber located on the side opposite to the piston rod is connected to the first port. A pressure chamber located on the same side as the piston rod is connected to the second port.
　これにより、ピストンロッドが単位長さだけ変位する場合に油圧シリンダの２つの圧力室の間で容積変化が異なるのに合わせて、油圧ポンプから作動油を吸入及び吐出することができる。 As a result, when the piston rod is displaced by a unit length, the hydraulic oil can be sucked in and discharged from the hydraulic pump according to the difference in volume between the two pressure chambers of the hydraulic cylinder.
　前記の油圧装置においては、以下の構成とすることが好ましい。即ち、この油圧装置は、前記油圧ポンプと前記油圧シリンダとの間で構成される閉回路に作動油を補充するための作動油供給部を備える。前記第１ポート、前記第２ポート及び前記第３ポートのうち、前記油圧シリンダに接続されたポート以外のポートが、前記作動油供給部と接続されている。 The hydraulic system described above preferably has the following configuration. That is, this hydraulic device includes a hydraulic oil supply unit for replenishing hydraulic oil in a closed circuit formed between the hydraulic pump and the hydraulic cylinder. Of the first port, the second port, and the third port, ports other than the port connected to the hydraulic cylinder are connected to the hydraulic oil supply unit.
　これにより、作動油供給部をバッファとして利用して、油圧ポンプにおける吐出量と吸入量の差によって閉回路での作動油の量が変動するのに対応することができる。 As a result, the hydraulic oil supply unit can be used as a buffer to cope with fluctuations in the amount of hydraulic oil in the closed circuit due to the difference between the discharge amount and the suction amount in the hydraulic pump.
　前記の油圧装置においては、前記第１ポート、前記第２ポート及び前記第３ポートのうち、前記油圧シリンダに接続されたポート以外のポートは、前記油圧ポンプのケーシングの内部を介して、前記作動油供給部と接続されていることが好ましい。 In the hydraulic device, of the first port, the second port, and the third port, ports other than the port connected to the hydraulic cylinder are operated via the inside of the casing of the hydraulic pump. It is preferably connected to the oil supply unit.
　これにより、ポートと作動油供給部とを接続するためのコンパクトな構成を実現することができる。 This makes it possible to realize a compact configuration for connecting the port and the hydraulic oil supply unit.
　前記の油圧装置においては、以下の構成とすることが好ましい。即ち、前記油圧ポンプのケーシングは、前記バルブプレートと対向する油路部材を備える。前記油路部材には、前記バルブプレート側に開口する凹部が形成される。前記シリンダブロックの回転軸心に沿って見たとき、前記凹部の開口部は、前記第３ポートより大きく、かつ前記第３ポートの全部を含んでいる。前記第３ポートが、前記凹部を介して、前記作動油供給部と接続されている。 The hydraulic system described above preferably has the following configuration. That is, the casing of the hydraulic pump includes an oil passage member facing the valve plate. The oil passage member is formed with a recess that opens on the valve plate side. When viewed along the rotation axis of the cylinder block, the opening of the recess is larger than the third port and includes the entire third port. The third port is connected to the hydraulic oil supply unit via the recess.
　これにより、作動油供給部と第３ポートとの間での作動油の流通が、油路部材に形成されるとともに第３ポートに直接接続された広い凹部を介して、円滑に行われる。従って、油圧ポンプにおいて、第３ポートから作動油を吸入する場合の自吸性能を向上させることができる。また、第３ポートから作動油を吐出する場合の圧力損失を低減することができる。 As a result, the flow of hydraulic oil between the hydraulic oil supply unit and the third port is smoothly performed through a wide recess formed in the oil passage member and directly connected to the third port. Therefore, in the hydraulic pump, the self-priming performance when the hydraulic oil is sucked from the third port can be improved. Further, it is possible to reduce the pressure loss when the hydraulic oil is discharged from the third port.
　前記の油圧装置においては、前記作動油供給部が、チャージポンプによって作動油を圧送するチャージ回路であることが好ましい。 In the hydraulic device, it is preferable that the hydraulic oil supply unit is a charge circuit that pumps hydraulic oil by a charge pump.
　これにより、油圧ポンプを利用して、チャージ回路から作動油を閉回路内に供給することができる。また、チャージポンプだけでなく前述の油圧ポンプを用いてチャージ回路に作動油を圧送できるので、その分、チャージポンプとして容量が小さいものを使用することができる。この結果、チャージポンプのコストを低減することができる。 This makes it possible to supply hydraulic oil from the charge circuit into the closed circuit using a hydraulic pump. Further, since the hydraulic oil can be pumped to the charge circuit by using not only the charge pump but also the above-mentioned hydraulic pump, a charge pump having a smaller capacity can be used accordingly. As a result, the cost of the charge pump can be reduced.
本発明の第１実施形態に係る油圧装置の油圧回路を示す図。The figure which shows the hydraulic circuit of the hydraulic apparatus which concerns on 1st Embodiment of this invention. 油圧装置が備える油圧ポンプの一部断面斜視図。Partial cross-sectional perspective view of the hydraulic pump provided in the hydraulic system. 油圧ポンプにおける複数のシリンダの位置関係を説明する図。The figure explaining the positional relationship of a plurality of cylinders in a hydraulic pump. 油圧ポンプにおけるバルブプレートを油路板側から見た図。The figure which looked at the valve plate in a hydraulic pump from the oil passage plate side. チャージ回路の一部の構成を示す断面図。The cross-sectional view which shows the structure of a part of the charge circuit. 本発明の第２実施形態に係る油圧装置の油圧回路を示す図。The figure which shows the hydraulic circuit of the hydraulic apparatus which concerns on 2nd Embodiment of this invention. バルブプレートと油路板の構成を示す分解斜視断面図。An exploded perspective sectional view showing the configuration of a valve plate and an oil passage plate. バルブプレートの変形例を示す図。The figure which shows the modification of the valve plate.
　次に、図面を参照して本発明の実施の形態を説明する。図１は、本発明の第１実施形態に係る油圧装置１の油圧回路を示す図である。 Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a hydraulic circuit of the hydraulic device 1 according to the first embodiment of the present invention.
　図１に示す油圧装置１は、油圧シリンダ５を有する機械（例えば、作業機）に適用される。作業機としては、例えば、バックホー等の掘削作業機、ホイールローダ等の土砂持上機等の対地作業機、梯子車等の昇降用アクチュエータ付車両を挙げることができる。 The hydraulic device 1 shown in FIG. 1 is applied to a machine having a hydraulic cylinder 5 (for example, a working machine). Examples of the work machine include excavation work machines such as backhoes, ground work machines such as earth and sand lifters such as wheel loaders, and vehicles with lifting actuators such as ladder trucks.
　油圧装置１は、油圧ポンプ３と、油圧シリンダ５と、を備える。油圧装置１は、油圧ポンプ３と油圧シリンダ５との間に配置される油圧回路を備える。この油圧回路は、油圧ポンプ３の吐出側から吐出される作動油を油圧シリンダ５に供給し、かつ、この油圧シリンダ５から排出される作動油を油圧ポンプ３の吸入側に戻す閉回路として構成されている。 The hydraulic device 1 includes a hydraulic pump 3 and a hydraulic cylinder 5. The hydraulic device 1 includes a hydraulic circuit arranged between the hydraulic pump 3 and the hydraulic cylinder 5. This hydraulic circuit is configured as a closed circuit that supplies the hydraulic oil discharged from the discharge side of the hydraulic pump 3 to the hydraulic cylinder 5 and returns the hydraulic oil discharged from the hydraulic cylinder 5 to the suction side of the hydraulic pump 3. Has been done.
　油圧シリンダ５は、片ロッド式の復動シリンダとして構成されている。油圧シリンダ５には、油圧シリンダ５の伸縮方向の両側に位置する２つの圧力室（具体的には、後述するボトム室２５及びヘッド室２７）が形成されている。油圧ポンプ３は、油圧シリンダ５を伸縮させるために、この２つの圧力室に選択的に作動油を給排することができる。 The hydraulic cylinder 5 is configured as a single-rod type recovery cylinder. The hydraulic cylinder 5 is formed with two pressure chambers (specifically, a bottom chamber 25 and a head chamber 27, which will be described later) located on both sides of the hydraulic cylinder 5 in the expansion / contraction direction. The hydraulic pump 3 can selectively supply and discharge hydraulic oil to the two pressure chambers in order to expand and contract the hydraulic cylinder 5.
　油圧シリンダ５は、ピストン３６と、ピストンロッド３７と、を備える。ピストン３６は、シリンダ内の空間に往復移動可能に配置されている。油圧シリンダ５の内部の空間は、ピストン３６によって、ボトム室２５とヘッド室２７とに区画される。 The hydraulic cylinder 5 includes a piston 36 and a piston rod 37. The piston 36 is arranged so as to be reciprocating in the space inside the cylinder. The space inside the hydraulic cylinder 5 is divided into a bottom chamber 25 and a head chamber 27 by a piston 36.
　ピストンロッド３７は、ピストン３６のヘッド室２７側の面に固定されており、ヘッド室２７を通過して外部へ延びている。従って、ピストン３６（ピストンロッド３７）が単位長さだけ変位した場合のヘッド室２７の容積の変化は、ボトム室２５の容積の変化よりも小さい。容積変化の比は、ピストンロッド３７の太さにもよるが、例えば、ボトム室：ヘッド室＝１００：５０～７０程度である。 The piston rod 37 is fixed to the surface of the piston 36 on the head chamber 27 side, passes through the head chamber 27, and extends to the outside. Therefore, the change in the volume of the head chamber 27 when the piston 36 (piston rod 37) is displaced by a unit length is smaller than the change in the volume of the bottom chamber 25. The ratio of the volume change depends on the thickness of the piston rod 37, but is, for example, about bottom chamber: head chamber = 100: 50 to 70.
　油圧ポンプ３は、電動モータ７により駆動される。油圧ポンプ３は、油圧シリンダ５の２つの圧力室のうち一方の圧力室から作動油を吸入し、他方の圧力室へ作動油を吐出する。 The hydraulic pump 3 is driven by the electric motor 7. The hydraulic pump 3 sucks hydraulic oil from one of the two pressure chambers of the hydraulic cylinder 5, and discharges the hydraulic oil to the other pressure chamber.
　油圧ポンプ３は、可動斜板式可変容量ポンプとして構成されている。可動斜板１１の傾斜角度を中立角度から傾けることによって、油圧ポンプ３が作動油の吸入及び吐出を行って、油圧シリンダ５を伸長又は収縮させることができる。可動斜板１１の傾斜角度は、油圧サーボ機構（可動斜板駆動機構）１３の作動により変更することができる。 The hydraulic pump 3 is configured as a movable swash plate type variable capacity pump. By tilting the tilt angle of the movable swash plate 11 from the neutral angle, the hydraulic pump 3 can suck and discharge hydraulic oil to extend or contract the hydraulic cylinder 5. The inclination angle of the movable swash plate 11 can be changed by operating the hydraulic servo mechanism (movable swash plate drive mechanism) 13.
　油圧ポンプ３は、複数（３以上）のポートを有する。本実施形態では、油圧ポンプ３には、第１ポート２１と、第２ポート２２と、第３ポート２３と、が形成されている。第１ポート２１及び第２ポート２２は、それぞれ、油圧ポンプ３が油圧シリンダ５に対し作動油の吸入又は吐出を行うとき、吸入ポート又は吐出ポートとして機能する。 The hydraulic pump 3 has a plurality of (3 or more) ports. In the present embodiment, the hydraulic pump 3 is formed with a first port 21, a second port 22, and a third port 23. The first port 21 and the second port 22 each function as a suction port or a discharge port when the hydraulic pump 3 sucks or discharges hydraulic oil to the hydraulic cylinder 5.
　第１ポート２１は、油圧シリンダ５のボトム室２５に第１油路３１を介して接続されている。第２ポート２２は、油圧シリンダ５のヘッド室２７に第２油路３２を介して接続されている。第３ポート２３は、作動油供給部としてのチャージ回路（チャージ圧供給部）３５が備えるチャージ油路３３に接続されている。 The first port 21 is connected to the bottom chamber 25 of the hydraulic cylinder 5 via the first oil passage 31. The second port 22 is connected to the head chamber 27 of the hydraulic cylinder 5 via the second oil passage 32. The third port 23 is connected to a charge oil passage 33 provided in a charge circuit (charge pressure supply unit) 35 as a hydraulic oil supply unit.
　チャージ回路３５は、油圧回路（閉回路）に作動油を補充する。チャージ回路３５には、後述の油路板８５に形成されたチャージ油路３３が含まれている。チャージ油路３３は、第１油路３１に接続されるとともに、第２油路３２に接続されている。 The charge circuit 35 replenishes the hydraulic circuit (closed circuit) with hydraulic oil. The charge circuit 35 includes a charge oil passage 33 formed in the oil passage plate 85 described later. The charge oil passage 33 is connected to the first oil passage 31 and is connected to the second oil passage 32.
　チャージ回路３５は、チャージポンプ３９を備える。チャージポンプ３９は、油圧ポンプであり、電動モータ４８により駆動される。この結果、例えば油圧ポンプ３からの作動油の漏れ等を原因として作動油が失われるのに応じて、閉回路に作動油が供給される。 The charge circuit 35 includes a charge pump 39. The charge pump 39 is a hydraulic pump and is driven by an electric motor 48. As a result, the hydraulic oil is supplied to the closed circuit in response to the loss of the hydraulic oil due to, for example, leakage of the hydraulic oil from the hydraulic pump 3.
　チャージポンプ３９の吸入ポートは、作動油が貯留された作動油タンクに接続されている。チャージポンプ３９の吐出ポートは、チャージ油路３３を介して、第１油路３１と、第２油路３２と、油圧ポンプ３の第３ポート２３と、にそれぞれ接続されている。 The suction port of the charge pump 39 is connected to the hydraulic oil tank in which the hydraulic oil is stored. The discharge port of the charge pump 39 is connected to the first oil passage 31, the second oil passage 32, and the third port 23 of the hydraulic pump 3, respectively, via the charge oil passage 33.
　チャージ回路３５は、更に油圧サーボ機構１３に接続されている。油圧サーボ機構１３は、チャージ回路３５から供給される作動油の油圧を用いて、可動斜板１１の角度を変更する。油圧サーボ機構１３の構成は公知であるため、詳細な説明は省略する。 The charge circuit 35 is further connected to the hydraulic servo mechanism 13. The hydraulic servo mechanism 13 changes the angle of the movable swash plate 11 by using the hydraulic pressure of the hydraulic oil supplied from the charge circuit 35. Since the configuration of the hydraulic servo mechanism 13 is known, detailed description thereof will be omitted.
　チャージ回路３５には、チャージリリーフ弁４９が設けられている。チャージリリーフ弁４９は、チャージ回路３５の油圧が所定圧以上となったときに開放される。これにより、チャージ回路３５の圧力が過大にならないようにすることができる。 The charge circuit 35 is provided with a charge relief valve 49. The charge relief valve 49 is opened when the oil pressure of the charge circuit 35 exceeds a predetermined pressure. As a result, the pressure of the charge circuit 35 can be prevented from becoming excessive.
　第１油路３１とチャージ油路３３との間には、チェックアンドリリーフ弁４１が配置されている。同様に、第２油路３２とチャージ油路３３との間には、チェックアンドリリーフ弁４２が配置されている。 A check and relief valve 41 is arranged between the first oil passage 31 and the charge oil passage 33. Similarly, a check and relief valve 42 is arranged between the second oil passage 32 and the charge oil passage 33.
　チェックアンドリリーフ弁４１は、第１油路３１の圧力がチャージ回路３５の圧力よりも低くなったときに開放される。従って、油圧ポンプ３が第１油路３１から作動油を吸入し、第１油路３１が低圧となったとき、チャージ回路３５から第１油路３１に作動油が供給される。また、チェックアンドリリーフ弁４１は、第１油路３１の圧力が所定の圧力を上回った場合に開放される。従って、第１油路３１の圧力が過大になったときは、第１油路３１の作動油をチャージ回路３５側へ逃がすことができる。 The check and relief valve 41 is opened when the pressure in the first oil passage 31 becomes lower than the pressure in the charge circuit 35. Therefore, when the hydraulic pump 3 sucks the hydraulic oil from the first oil passage 31 and the first oil passage 31 becomes low pressure, the hydraulic oil is supplied from the charge circuit 35 to the first oil passage 31. Further, the check and relief valve 41 is opened when the pressure of the first oil passage 31 exceeds a predetermined pressure. Therefore, when the pressure in the first oil passage 31 becomes excessive, the hydraulic oil in the first oil passage 31 can be released to the charge circuit 35 side.
　チェックアンドリリーフ弁４２は、第２油路３２の圧力がチャージ回路３５の圧力よりも低くなったときに開放される。従って、油圧ポンプ３が第２油路３２から作動油を吸入し、第２油路３２が低圧となったとき、チャージ回路３５から第２油路３２に作動油が供給される。また、チェックアンドリリーフ弁４２は、第２油路３２の圧力が所定の圧力を上回った場合に開放される。従って、第２油路３２の圧力が過大になったときは、第２油路３２の作動油をチャージ回路３５側へ逃がすことができる。 The check and relief valve 42 is opened when the pressure in the second oil passage 32 becomes lower than the pressure in the charge circuit 35. Therefore, when the hydraulic pump 3 sucks the hydraulic oil from the second oil passage 32 and the second oil passage 32 becomes low pressure, the hydraulic oil is supplied from the charge circuit 35 to the second oil passage 32. Further, the check and relief valve 42 is opened when the pressure of the second oil passage 32 exceeds a predetermined pressure. Therefore, when the pressure in the second oil passage 32 becomes excessive, the hydraulic oil in the second oil passage 32 can be released to the charge circuit 35 side.
　チェックアンドリリーフ弁４１，４２は、チェック弁とリリーフ弁を一体化した構成となっており、詳細は後述する。 The check and relief valves 41 and 42 have a configuration in which the check valve and the relief valve are integrated, and the details will be described later.
　第１油路３１において、第１ポート２１と油圧シリンダ５との間にはチェック弁５３が配置されている。第２油路３２において、第２ポート２２と油圧シリンダ５との間にはチェック弁５４が配置されている。この２つのチェック弁５３，５４により、シリンダ保持機構５１が構成される。 In the first oil passage 31, a check valve 53 is arranged between the first port 21 and the hydraulic cylinder 5. In the second oil passage 32, a check valve 54 is arranged between the second port 22 and the hydraulic cylinder 5. The cylinder holding mechanism 51 is configured by these two check valves 53 and 54.
　油圧ポンプ３が駆動を停止した状態で、油圧シリンダ５のピストンロッド３７が移動しようとした場合、チェック弁５３及びチェック弁５４のうち何れか一方が、油圧シリンダ５から第１油路３１又は第２油路３２への作動油の通過を阻止する。従って、ピストンロッド３７の位置を保持することができる。一方、油圧ポンプ３が駆動して、例えば第１油路３１の圧力が上昇した場合は、この第１油路３１の圧力がチェック弁５４に導かれるので、チェック弁５４が強制的に開弁される。従って、油圧シリンダ５から第２油路３２への作動油の通過が許容され、油圧シリンダ５を駆動することができる。 When the piston rod 37 of the hydraulic cylinder 5 tries to move while the hydraulic pump 3 is stopped, one of the check valve 53 and the check valve 54 is connected to the first oil passage 31 or the first oil passage 31 from the hydraulic cylinder 5. 2 Prevents the passage of hydraulic oil through the oil passage 32. Therefore, the position of the piston rod 37 can be maintained. On the other hand, when the hydraulic pump 3 is driven and the pressure in the first oil passage 31 rises, for example, the pressure in the first oil passage 31 is guided to the check valve 54, so that the check valve 54 is forcibly opened. Will be done. Therefore, the passage of hydraulic oil from the hydraulic cylinder 5 to the second oil passage 32 is allowed, and the hydraulic cylinder 5 can be driven.
　次に、図２から図４までを参照して、油圧ポンプ３の構成について詳細に説明する。図２は、油圧装置１が備える油圧ポンプ３の一部断面斜視図である。図３は、油圧ポンプ３における複数のピストン穴６９の位置関係を説明する図である。図４は、油圧ポンプ３におけるバルブプレート６７を油路板８５側から見た図である。 Next, the configuration of the hydraulic pump 3 will be described in detail with reference to FIGS. 2 to 4. FIG. 2 is a partial cross-sectional perspective view of the hydraulic pump 3 included in the hydraulic device 1. FIG. 3 is a diagram for explaining the positional relationship of the plurality of piston holes 69 in the hydraulic pump 3. FIG. 4 is a view of the valve plate 67 of the hydraulic pump 3 as viewed from the oil passage plate 85 side.
　油圧ポンプ３は、アキシャルピストン型の油圧ポンプである。図２に示すように、油圧ポンプ３は、シャフト６１と、シリンダブロック６３と、複数のピストン６５と、バルブプレート６７と、可動斜板１１と、ケーシング７０と、を備える。 The hydraulic pump 3 is an axial piston type hydraulic pump. As shown in FIG. 2, the hydraulic pump 3 includes a shaft 61, a cylinder block 63, a plurality of pistons 65, a valve plate 67, a movable swash plate 11, and a casing 70.
　シャフト６１は、ケーシング７０に回転可能に支持されている。シャフト６１は、ケーシング７０の外部で電動モータ７に接続されている。電動モータ７の駆動力が伝達されることにより、シャフト６１は、当該シャフト６１の軸心７１まわりに回転する。 The shaft 61 is rotatably supported by the casing 70. The shaft 61 is connected to the electric motor 7 outside the casing 70. By transmitting the driving force of the electric motor 7, the shaft 61 rotates around the axis 71 of the shaft 61.
　シリンダブロック６３は、ケーシング７０の内部に配置されている。シリンダブロック６３は、円筒状に形成され、シャフト６１の周囲に配置されている。シリンダブロック６３は、シャフト６１の長手方向の途中部に固定されている。従って、シャフト６１が回転すると、シリンダブロック６３はシャフト６１と一体的に回転する。シリンダブロック６３の回転軸心は、シャフト６１の軸心７１と一致する。 The cylinder block 63 is arranged inside the casing 70. The cylinder block 63 is formed in a cylindrical shape and is arranged around the shaft 61. The cylinder block 63 is fixed in the middle of the shaft 61 in the longitudinal direction. Therefore, when the shaft 61 rotates, the cylinder block 63 rotates integrally with the shaft 61. The rotation axis of the cylinder block 63 coincides with the axis 71 of the shaft 61.
　シリンダブロック６３には、複数のピストン穴６９が形成されている。それぞれのピストン穴６９は、円柱状に形成されている。シリンダブロック６３の回転軸心（上述の軸心７１）に沿って当該シリンダブロック６３を見たときに、複数のピストン穴６９の中心は、回転軸心を中心とする２つの同心円を仮想したときに、この同心円に沿って並べて配置されている。具体的には、図３に示すように、大径（直径ｄ１）の第１円９１に沿って５つのピストン穴６９Ａが等間隔に並べて形成され、小径（直径ｄ２、ｄ２＜ｄ１）の第２円９２に沿って５つのピストン穴６９Ｂが等間隔に並べて形成されている。複数のピストン穴６９は何れも、シャフト６１の軸心７１と平行な方向に細長く形成されている。従って、複数のピストン穴６９は互いに平行に向けられている。 A plurality of piston holes 69 are formed in the cylinder block 63. Each piston hole 69 is formed in a columnar shape. When the cylinder block 63 is viewed along the rotation axis of the cylinder block 63 (the above-mentioned axis 71), the centers of the plurality of piston holes 69 are assumed to be two concentric circles centered on the rotation axis. They are arranged side by side along this concentric circle. Specifically, as shown in FIG. 3, five piston holes 69A are formed so as to be arranged at equal intervals along the first circle 91 having a large diameter (diameter d1), and the first circle having a small diameter (diameter d2, d2 <d1). Five piston holes 69B are formed so as to be arranged at equal intervals along the 2 circle 92. Each of the plurality of piston holes 69 is elongated in a direction parallel to the axis 71 of the shaft 61. Therefore, the plurality of piston holes 69 are oriented parallel to each other.
　外周側の５つのピストン穴６９Ａの直径ｄ３は互いに同一であり、内周側の５つのピストン穴６９Ｂの直径ｄ４は互いに同一である。本実施形態において、外周側のピストン穴６９Ａの直径ｄ３は、内周側のピストン穴６９Ｂの直径ｄ４よりも大きい（ｄ３＞ｄ４）。シリンダブロック６３において、外周側のピストン穴６９Ａが配置される位相と、内周側のピストン穴６９Ｂが配置される位相とが、等角度間隔で交互に現れる。 The diameters d3 of the five piston holes 69A on the outer peripheral side are the same as each other, and the diameters d4 of the five piston holes 69B on the inner peripheral side are the same as each other. In the present embodiment, the diameter d3 of the piston hole 69A on the outer peripheral side is larger than the diameter d4 of the piston hole 69B on the inner peripheral side (d3> d4). In the cylinder block 63, the phase in which the piston holes 69A on the outer peripheral side are arranged and the phase in which the piston holes 69B on the inner peripheral side are arranged appear alternately at equal angular intervals.
　複数のピストン６５は、円柱形状を有し、複数のピストン穴６９のそれぞれに取り付けられている。外周側のピストン穴６９Ａには外周側のピストン６５Ａが配置され、内周側のピストン穴６９Ｂには内周側のピストン６５Ｂが配置される。それぞれのピストン６５Ａ，６５Ｂの直径は、当該ピストン６５Ａ，６５Ｂが配置されるピストン穴６９Ａ，６９Ｂの直径に対応している。 The plurality of pistons 65 have a cylindrical shape and are attached to each of the plurality of piston holes 69. The outer peripheral side piston 65A is arranged in the outer peripheral side piston hole 69A, and the inner peripheral side piston 65B is arranged in the inner peripheral side piston hole 69B. The diameters of the pistons 65A and 65B correspond to the diameters of the piston holes 69A and 69B in which the pistons 65A and 65B are arranged.
　複数のピストン６５のそれぞれは、ピストン穴６９に嵌められた状態で、シャフト６１の軸心７１と平行な方向に往復動することができる。ピストン６５の移動により、ピストン穴６９への作動油の吸入／吐出が行われる。 Each of the plurality of pistons 65 can reciprocate in a direction parallel to the axis 71 of the shaft 61 while being fitted in the piston hole 69. By moving the piston 65, the hydraulic oil is sucked / discharged into the piston hole 69.
　各ピストン６５が往復動する方向の一側の端部（シュー部）には、図２に示すように、シュー部を保持するリテーナプレート７３が設けられている。リテーナプレート７３は、可動斜板１１に形成された平坦な案内面７４に接続されている。前述の油圧サーボ機構１３は、可動斜板１１の角度を変更することで、シャフト６１の軸心７１に対する案内面７４の傾斜角度を調節することができる。 As shown in FIG. 2, a retainer plate 73 for holding the shoe portion is provided at one end (shoe portion) in the direction in which each piston 65 reciprocates. The retainer plate 73 is connected to a flat guide surface 74 formed on the movable swash plate 11. The above-mentioned hydraulic servo mechanism 13 can adjust the inclination angle of the guide surface 74 with respect to the axis 71 of the shaft 61 by changing the angle of the movable swash plate 11.
　第１接続孔８１及び第２接続孔８２は、それぞれのピストン穴６９に対して作動油を吸入／吐出するために、シリンダブロック６３に形成されている。第１接続孔８１及び第２接続孔８２は、シリンダブロック６３における軸方向一側（可動斜板１１から遠い側）の面に開口している。以下では、シリンダブロック６３において第１接続孔８１及び第２接続孔８２が開口されている面を、吸入・吐出面７５と呼ぶことがある。第１接続孔８１は外周側のピストン穴６９Ａに接続され、第２接続孔８２は内周側のピストン穴６９Ｂに接続されている。 The first connection hole 81 and the second connection hole 82 are formed in the cylinder block 63 in order to suck / discharge hydraulic oil to each piston hole 69. The first connection hole 81 and the second connection hole 82 are open on one side in the axial direction (the side far from the movable swash plate 11) of the cylinder block 63. Hereinafter, the surface of the cylinder block 63 in which the first connection hole 81 and the second connection hole 82 are opened may be referred to as a suction / discharge surface 75. The first connection hole 81 is connected to the piston hole 69A on the outer peripheral side, and the second connection hole 82 is connected to the piston hole 69B on the inner peripheral side.
　第１接続孔８１及び第２接続孔８２は、シリンダブロック６３の回転軸心（上述の軸心７１）の周囲に、２つの同心円に沿って並べて配置されている。具体的には、大径の円に沿って５つの第１接続孔８１が等間隔に並べて形成され、小径の円に沿って５つの第２接続孔８２が等間隔に並べて形成されている。 The first connection hole 81 and the second connection hole 82 are arranged side by side along two concentric circles around the rotation axis of the cylinder block 63 (the above-mentioned axis 71). Specifically, five first connection holes 81 are formed by arranging them at equal intervals along a large-diameter circle, and five second connection holes 82 are formed by arranging them at equal intervals along a small-diameter circle.
　第１接続孔８１及び第２接続孔８２は、それぞれ、シリンダブロック６３の回転軸心を中心とする円弧状の孔から構成されている。シリンダブロック６３において、第１接続孔８１が配置される位相と、第２接続孔８２が配置される位相とが、等角度間隔で交互に現れる。 The first connection hole 81 and the second connection hole 82 are each composed of an arc-shaped hole centered on the rotation axis of the cylinder block 63. In the cylinder block 63, the phase in which the first connection hole 81 is arranged and the phase in which the second connection hole 82 is arranged appear alternately at equal angular intervals.
　バルブプレート６７は、板状の部材である。バルブプレート６７は、ケーシング７０に備えられた油路板（油路部材）８５に対向した状態で固定されている。油路板８５の内部には、第１油路３１、第２油路３２、及びチャージ油路３３等が形成されている。バルブプレート６７には、シャフト６１を差し込むための貫通状の軸孔６２が形成されている。 The valve plate 67 is a plate-shaped member. The valve plate 67 is fixed so as to face the oil passage plate (oil passage member) 85 provided in the casing 70. Inside the oil passage plate 85, a first oil passage 31, a second oil passage 32, a charge oil passage 33, and the like are formed. The valve plate 67 is formed with a through-shaped shaft hole 62 for inserting the shaft 61.
　バルブプレート６７は、円板状に形成されている。バルブプレート６７は、シリンダブロック６３と同程度の径を有する。バルブプレート６７の厚み方向一側の面は、接触面６８となっている。この接触面６８は、回転するシリンダブロック６３における上述の吸入・吐出面７５に対し、滑りながら接触する。 The valve plate 67 is formed in a disk shape. The valve plate 67 has a diameter similar to that of the cylinder block 63. One surface of the valve plate 67 in the thickness direction is a contact surface 68. The contact surface 68 slides into contact with the suction / discharge surface 75 of the rotating cylinder block 63.
　バルブプレート６７は、第１ポート２１と、第２ポート２２と、第３ポート２３と、を有する。バルブプレート６７において、第１ポート２１、第２ポート２２、及び第３ポート２３は、それぞれ、前述の接触面６８に開口するように設けられている。 The valve plate 67 has a first port 21, a second port 22, and a third port 23. In the valve plate 67, the first port 21, the second port 22, and the third port 23 are each provided so as to open to the above-mentioned contact surface 68.
　第１ポート２１は、図４に示すように、バルブプレート６７に相当する円を半分に分割した半円状の領域（第１半円領域６７ａ）に対応して形成されている。２つの半円状の領域の境界は、シリンダブロック６３の回転軸心に垂直であり、かつ、可動斜板１１が傾く中心軸に垂直な直線である。この境界は、後述のピストン６５が吸入行程と吐出行程との間で切り換わる境界ということもできる。 As shown in FIG. 4, the first port 21 is formed corresponding to a semicircular region (first semicircular region 67a) in which a circle corresponding to the valve plate 67 is divided in half. The boundary between the two semicircular regions is a straight line perpendicular to the center of rotation of the cylinder block 63 and perpendicular to the central axis on which the movable swash plate 11 is tilted. This boundary can also be said to be the boundary at which the piston 65, which will be described later, switches between the suction stroke and the discharge stroke.
　第１ポート２１は、シリンダブロック６３の回転軸心を中心とする円弧状の長孔から構成されている。この長孔は、所定の角度範囲にある第１接続孔８１及び第２接続孔８２の何れにも対面できるように、第２ポート２２及び第３ポート２３と比較して幅広に形成されている。 The first port 21 is composed of an arcuate elongated hole centered on the rotation axis of the cylinder block 63. This elongated hole is formed wider than the second port 22 and the third port 23 so that it can face any of the first connection hole 81 and the second connection hole 82 in a predetermined angle range. ..
　第１ポート２１は、油路板８５の内部に形成された第１油路３１と接続されている。第１ポート２１は、複数のピストン穴６９に、シリンダブロック６３の第１接続孔８１及び第２接続孔８２を介して接続することができる。 The first port 21 is connected to the first oil passage 31 formed inside the oil passage plate 85. The first port 21 can be connected to a plurality of piston holes 69 via the first connection hole 81 and the second connection hole 82 of the cylinder block 63.
　第２ポート２２は、バルブプレート６７を上述のように２つの半円状の領域に分けたときに、第１ポート２１が設けられた側と反対側の領域（第２半円領域６７ｂ）に配置されている。第２ポート２２は、シリンダブロック６３の回転軸心を中心とする円弧状の長孔から構成されている。この長孔は、所定の角度範囲にある第１接続孔８１と対面することができる。 When the valve plate 67 is divided into two semicircular regions as described above, the second port 22 is formed in a region (second semicircular region 67b) opposite to the side where the first port 21 is provided. Have been placed. The second port 22 is composed of an arcuate elongated hole centered on the rotation axis of the cylinder block 63. This elongated hole can face the first connection hole 81 in a predetermined angle range.
　第２ポート２２は、油路板８５の内部に形成された第２油路３２と接続されている。第２ポート２２は、複数のピストン穴６９のうち外周側のピストン穴６９Ａに、シリンダブロック６３の第１接続孔８１を介して接続することができる。一方、第２ポート２２は第２接続孔８２に対して外周側に外れて位置しているため、第２ポート２２が第２接続孔８２と接続することはない。 The second port 22 is connected to the second oil passage 32 formed inside the oil passage plate 85. The second port 22 can be connected to the piston hole 69A on the outer peripheral side of the plurality of piston holes 69 via the first connection hole 81 of the cylinder block 63. On the other hand, since the second port 22 is located on the outer peripheral side with respect to the second connection hole 82, the second port 22 does not connect to the second connection hole 82.
　第３ポート２３は、バルブプレート６７を上述のように２つの半円状の領域に分けたときに、第２ポート２２と同じ側の領域（第２半円領域６７ｂ）に配置されている。第３ポート２３は、シリンダブロック６３の回転軸心を中心とする円弧状の長孔から構成されている。この長孔は、所定の角度範囲にある第２接続孔８２と対面することができる。第３ポート２３は、第２ポート２２よりも内周側に配置されている。 The third port 23 is arranged in the region on the same side as the second port 22 (second semicircular region 67b) when the valve plate 67 is divided into two semicircular regions as described above. The third port 23 is composed of an arcuate elongated hole centered on the rotation axis of the cylinder block 63. This elongated hole can face the second connection hole 82 in a predetermined angle range. The third port 23 is arranged on the inner peripheral side of the second port 22.
　第３ポート２３は、油路板８５に形成されたチャージ油路３３と接続されている。チャージ油路３３は、第１油路３１と第２油路３２の間に位置している。第３ポート２３は、複数のピストン穴６９のうち内周側のピストン穴６９Ｂに、シリンダブロック６３の第２接続孔８２を介して接続することができる。一方、第３ポート２３は第１接続孔８１に対して内周側に外れて位置しているため、第３ポート２３が第１接続孔８１と接続することはない。 The third port 23 is connected to the charge oil passage 33 formed in the oil passage plate 85. The charge oil passage 33 is located between the first oil passage 31 and the second oil passage 32. The third port 23 can be connected to the piston hole 69B on the inner peripheral side of the plurality of piston holes 69 via the second connection hole 82 of the cylinder block 63. On the other hand, since the third port 23 is located on the inner peripheral side of the first connection hole 81, the third port 23 does not connect to the first connection hole 81.
　以上の構成で、油圧ポンプ３は、シャフト６１の回転駆動に伴ってシリンダブロック６３を回転させ、これにより、複数のピストン６５を可動斜板１１に追従するように往復運動させる。これにより、ピストン６５のそれぞれは、吸入、吐出のポンプ作用を繰り返す。 With the above configuration, the hydraulic pump 3 rotates the cylinder block 63 with the rotational drive of the shaft 61, whereby the plurality of pistons 65 are reciprocated so as to follow the movable swash plate 11. As a result, each of the pistons 65 repeats the pumping action of suction and discharge.
　外周側に配置されたピストン穴６９Ａは、シリンダブロック６３の回転に伴って、バルブプレート６７の第１ポート２１及び第２ポート２２に対して開閉される。内周側に配置されたピストン穴６９Ｂは、シリンダブロック６３の回転に伴って、バルブプレート６７の第１ポート２１及び第３ポート２３に対して開閉される。 The piston hole 69A arranged on the outer peripheral side is opened and closed with respect to the first port 21 and the second port 22 of the valve plate 67 as the cylinder block 63 rotates. The piston hole 69B arranged on the inner peripheral side is opened and closed with respect to the first port 21 and the third port 23 of the valve plate 67 as the cylinder block 63 rotates.
　可動斜板１１を中立状態から一側に傾斜させた場合、バルブプレート６７の第１ポート２１に接続しているピストン穴６９でピストン６５が吸入行程となり、第２ポート２２及び第３ポート２３に接続しているピストン穴６９でピストン６５が吐出行程となる。 When the movable swash plate 11 is tilted to one side from the neutral state, the piston 65 becomes a suction stroke in the piston hole 69 connected to the first port 21 of the valve plate 67, and becomes the second port 22 and the third port 23. The piston 65 serves as a discharge stroke in the connected piston hole 69.
　油圧ポンプ３は、油圧シリンダ５のボトム室２５の作動油を、第１ポート２１から、ピストン６５が吸入行程となっている外周側のピストン穴６９Ａ及び内周側のピストン穴６９Ｂに吸入する。シリンダブロック６３の回転に伴ってピストン６５が吸入行程から吐出行程に切り換わると、外周側のピストン穴６９Ａの作動油は第２ポート２２から吐出され、内周側のピストン穴６９Ｂの作動油は第３ポート２３から吐出される。これにより、１つのポートから吸入した作動油を、所定の比率で分流して２つのポートから吐出することができる。第２ポート２２から吐出された作動油は、油圧シリンダ５を縮めるために、ヘッド室２７に供給される。第３ポート２３から吐出された作動油は、チャージ回路３５に排出される。 The hydraulic pump 3 sucks the hydraulic oil from the bottom chamber 25 of the hydraulic cylinder 5 from the first port 21 into the piston hole 69A on the outer peripheral side and the piston hole 69B on the inner peripheral side where the piston 65 is the suction stroke. When the piston 65 is switched from the suction stroke to the discharge stroke as the cylinder block 63 rotates, the hydraulic oil in the piston hole 69A on the outer peripheral side is discharged from the second port 22, and the hydraulic oil in the piston hole 69B on the inner peripheral side is discharged. It is discharged from the third port 23. As a result, the hydraulic oil sucked from one port can be divided at a predetermined ratio and discharged from the two ports. The hydraulic oil discharged from the second port 22 is supplied to the head chamber 27 in order to contract the hydraulic cylinder 5. The hydraulic oil discharged from the third port 23 is discharged to the charge circuit 35.
　可動斜板１１を中立状態から上記と反対側に傾斜させた場合、バルブプレート６７の第２ポート２２及び第３ポート２３に接続しているピストン穴６９でピストン６５が吸入行程となり、第１ポート２１に接続しているピストン穴６９でピストン６５が吐出行程となる。 When the movable swash plate 11 is tilted from the neutral state to the opposite side to the above, the piston 65 becomes the suction stroke in the piston hole 69 connected to the second port 22 and the third port 23 of the valve plate 67, and the first port The piston 65 serves as a discharge stroke in the piston hole 69 connected to the 21.
　油圧ポンプ３は、油圧シリンダ５のヘッド室２７の作動油を、第２ポート２２から、ピストン６５が吸入行程となっている外周側のピストン穴６９Ａに吸入する。更に、油圧ポンプ３は、チャージ回路３５の作動油を、第３ポート２３から、ピストン６５が吸入行程となっている内周側のピストン穴６９Ｂに吸入する。シリンダブロック６３の回転に伴ってピストン６５が吸入行程から吐出行程に切り換わると、外周側のピストン穴６９Ａの作動油、及び、内周側のピストン穴６９Ｂの作動油は、何れも第１ポート２１から吐出される。これにより、互いに異なるポートから所定の比率で吸入した作動油を、１つのポートに合流して吐出することができる。第１ポート２１から吐出された作動油は、油圧シリンダ５を伸ばすために、ボトム室２５に供給される。 The hydraulic pump 3 sucks the hydraulic oil from the head chamber 27 of the hydraulic cylinder 5 from the second port 22 into the piston hole 69A on the outer peripheral side where the piston 65 is the suction stroke. Further, the hydraulic pump 3 sucks the hydraulic oil of the charge circuit 35 from the third port 23 into the piston hole 69B on the inner peripheral side where the piston 65 is the suction stroke. When the piston 65 is switched from the suction stroke to the discharge stroke as the cylinder block 63 rotates, the hydraulic oil in the piston hole 69A on the outer peripheral side and the hydraulic oil in the piston hole 69B on the inner peripheral side are both in the first port. It is discharged from 21. As a result, hydraulic oil sucked from different ports at a predetermined ratio can be merged into one port and discharged. The hydraulic oil discharged from the first port 21 is supplied to the bottom chamber 25 in order to extend the hydraulic cylinder 5.
　このように、油圧シリンダ５をストロークさせる場合のボトム室２５とヘッド室２７との作動油の供給量と排出量との間の差を解消して、油圧シリンダ５を作動させることができる。 In this way, the hydraulic cylinder 5 can be operated by eliminating the difference between the supply amount and the discharge amount of the hydraulic oil between the bottom chamber 25 and the head chamber 27 when the hydraulic cylinder 5 is stroked.
　本実施形態では、シリンダブロック６３において、１０個のピストン穴６９を、外周側と内周側で５個ずつ振り分けて配置している。また、上述の第２半円領域６７ｂにおいて、外周側のピストン穴６９Ａは第２ポート２２にのみ接続し、内周側のピストン穴６９Ｂは第３ポート２３にのみ接続する。従って、ピストン穴６９の１つに着目すると、ピストン６５の吸入行程の途中及び吐出行程の途中でピストン穴６９の接続先のポートが切り換わらないため、ピストン穴６９から給排される作動油の流量変動があまり大きくならない。この結果、上述の作動油の分流及び合流を実現しつつ、油圧ポンプ３から発生する騒音を低減でき、また、吐出圧力も安定させることができる。 In the present embodiment, in the cylinder block 63, 10 piston holes 69 are arranged by dividing them into 5 on the outer peripheral side and 5 on the inner peripheral side. Further, in the above-mentioned second semicircular region 67b, the piston hole 69A on the outer peripheral side is connected only to the second port 22, and the piston hole 69B on the inner peripheral side is connected only to the third port 23. Therefore, focusing on one of the piston holes 69, since the port to which the piston hole 69 is connected does not switch during the suction stroke and the discharge stroke of the piston 65, the hydraulic oil supplied and discharged from the piston hole 69 The flow rate fluctuation does not become so large. As a result, the noise generated from the hydraulic pump 3 can be reduced and the discharge pressure can be stabilized while realizing the above-mentioned diversion and merging of the hydraulic oil.
　ところで、本実施形態の油圧ポンプ３では、１０個のピストン穴６９を、大径の第１円９１と小径の第２円９２に振り分けて周方向で交互に並べた構成となっている。言い換えれば、５つの外周側のピストン穴６９Ａと５つの内周側のピストン穴６９Ｂとが、シリンダブロック６３の回転軸心を中心とする周方向で千鳥状に配置されている。 By the way, the hydraulic pump 3 of the present embodiment has a configuration in which 10 piston holes 69 are divided into a large-diameter first circle 91 and a small-diameter second circle 92 and arranged alternately in the circumferential direction. In other words, the five piston holes 69A on the outer peripheral side and the five piston holes 69B on the inner peripheral side are arranged in a staggered manner in the circumferential direction centered on the rotation axis of the cylinder block 63.
　外周側／内周側を問わずピストン６５は可動斜板１１に沿って運動するので、外周側のピストン穴６９Ａは、内周側のピストン穴６９Ｂと比べて、シリンダブロック６３の回転に伴うピストン６５の往復ストロークが大きくなる。従って、仮にｄ３＝ｄ４、即ち、外周側と内周側とでピストン穴６９の直径が同一の場合でも、ピストン６５のストロークの差を利用して、上述した油圧シリンダ５の容積変化の比（例えば、１００：５０～７０）に適合した吸入吐出比を実現することが容易になる。 Since the piston 65 moves along the movable swash plate 11 regardless of the outer peripheral side / inner peripheral side, the piston hole 69A on the outer peripheral side is a piston that accompanies the rotation of the cylinder block 63 as compared with the piston hole 69B on the inner peripheral side. The reciprocating stroke of 65 becomes large. Therefore, even if d3 = d4, that is, even if the diameters of the piston holes 69 are the same on the outer peripheral side and the inner peripheral side, the ratio of the volume change of the hydraulic cylinder 5 described above can be utilized by utilizing the difference in the strokes of the piston 65. For example, it becomes easy to realize an intake / discharge ratio suitable for 100: 50 to 70).
　本実施形態では、外周側のピストン穴６９Ａの直径ｄ３は、内周側のピストン穴６９Ｂの直径ｄ４よりも、大きくなっている（ｄ３＞ｄ４）。直径ｄ３，ｄ４は互いに等しくしても差し支えないが、互いに異ならせることで、吸入吐出比の設計の自由度を更に高めることができる。 In the present embodiment, the diameter d3 of the piston hole 69A on the outer peripheral side is larger than the diameter d4 of the piston hole 69B on the inner peripheral side (d3> d4). The diameters d3 and d4 may be equal to each other, but by making them different from each other, the degree of freedom in designing the suction / discharge ratio can be further increased.
　図３において破線のハッチングで示すように、周方向で隣り合う２つのピストン穴６９Ａ，６９Ｂは、シリンダブロック６３の回転軸心を中心とする径方向で、互いに部分的に重複するように配置される。これにより、ピストン穴６９の高密度配置を実現でき、シリンダブロック６３を特に径方向でコンパクトに構成することができる。言い換えれば、同一の大きさでも、高容量化した油圧ポンプ３を実現することができる。 As shown by the hatching of the broken line in FIG. 3, the two piston holes 69A and 69B adjacent to each other in the circumferential direction are arranged so as to partially overlap each other in the radial direction centered on the rotation axis of the cylinder block 63. To. As a result, a high-density arrangement of the piston holes 69 can be realized, and the cylinder block 63 can be configured compactly particularly in the radial direction. In other words, it is possible to realize a hydraulic pump 3 having a high capacity even if the size is the same.
　次に、図５を参照して、チェックアンドリリーフ弁４１，４２の構成を説明する。 Next, the configurations of the check and relief valves 41 and 42 will be described with reference to FIG.
　チェックアンドリリーフ弁４１は、チェック弁体４３と、リリーフ弁体４４と、を備える。 The check and relief valve 41 includes a check valve body 43 and a relief valve body 44.
　チェック弁体４３は、第１油路３１とチャージ油路３３とを繋ぐ油孔８６に、往復移動可能に配置されている。チェック弁体４３は、油孔８６に沿って移動することで、当該油孔８６を開閉することができる。チェックアンドリリーフ弁４１には、チェック弁体４３を（リリーフ弁体４４及び後述のリリーフバネ４６を介して）閉弁方向に付勢するチェックバネ４５が設けられている。チェック弁体４３は、第１油路３１からチャージ油路３３へ向かう作動油の流れを阻止し、その逆の流れを許容するように動作する。 The check valve body 43 is arranged so as to be reciprocally movable in the oil hole 86 connecting the first oil passage 31 and the charge oil passage 33. The check valve body 43 can open and close the oil hole 86 by moving along the oil hole 86. The check and relief valve 41 is provided with a check spring 45 that urges the check valve body 43 (via the relief valve body 44 and the relief spring 46 described later) in the valve closing direction. The check valve body 43 operates so as to block the flow of hydraulic oil from the first oil passage 31 to the charge oil passage 33 and allow the reverse flow.
　リリーフ弁体４４は、油孔８６に沿う向きに細長い部材であり、油孔８６に往復移動可能に配置されている。リリーフ弁体４４の軸方向一端部は、チェック弁体４３に形成された逃がし孔４７に差し込まれている。チェックアンドリリーフ弁４１には、リリーフバネ４６が設けられている。リリーフバネ４６は、リリーフ弁体４４をチェック弁体４３に対して閉弁方向に付勢する。第１油路３１の圧力によってリリーフ弁体４４が押される力が、リリーフバネ４６のバネ力を上回ると、リリーフ弁体４４が開く。これにより、第１油路３１から逃がし孔４７を介してチャージ油路３３へ作動油を逃がすことができる。 The relief valve body 44 is an elongated member in the direction along the oil hole 86, and is arranged so as to be reciprocally movable in the oil hole 86. One end of the relief valve body 44 in the axial direction is inserted into a relief hole 47 formed in the check valve body 43. The check and relief valve 41 is provided with a relief spring 46. The relief spring 46 urges the relief valve body 44 with respect to the check valve body 43 in the valve closing direction. When the force pushing the relief valve body 44 by the pressure of the first oil passage 31 exceeds the spring force of the relief spring 46, the relief valve body 44 opens. As a result, the hydraulic oil can be released from the first oil passage 31 to the charge oil passage 33 through the relief hole 47.
　チェックアンドリリーフ弁４２の構成は、上述のチェックアンドリリーフ弁４１と全く同様であるので、説明を省略する。 The configuration of the check and relief valve 42 is exactly the same as that of the check and relief valve 41 described above, so the description thereof will be omitted.
　本実施形態では、第３ポート２３に対して作動油を吸入／吐出し、かつ、チャージポンプ３９からチェックアンドリリーフ弁４１，４２を介して第１油路３１及び第２油路３２に作動油を供給するための経路が、油路板８５に形成された油路（チャージ油路３３）として構成されている。従って、特別な配管を設ける必要がないので、構成の簡素化及び小型化を実現することができる。 In the present embodiment, the hydraulic oil is sucked / discharged to the third port 23, and the hydraulic oil is supplied from the charge pump 39 to the first oil passage 31 and the second oil passage 32 via the check and relief valves 41 and 42. The path for supplying the oil is configured as an oil passage (charge oil passage 33) formed in the oil passage plate 85. Therefore, since it is not necessary to provide special piping, it is possible to realize simplification and miniaturization of the configuration.
　以上に説明したように、本実施形態の油圧ポンプ３は、シリンダブロック６３と、複数のピストン６５と、バルブプレート６７と、を備える。シリンダブロック６３は、回転可能に支持される。シリンダブロック６３には、複数のピストン穴６９が回転軸心まわりに形成される。ピストン６５は、複数のピストン穴６９のそれぞれに取り付けられる。バルブプレート６７は、ピストン穴６９に接続される油路をシリンダブロック６３の回転に応じて切り換える。バルブプレート６７には、第１ポート２１と、第２ポート２２と、第３ポート２３と、が形成される。第１ポート２１は、シリンダブロック６３の回転軸心の周囲の円形の領域を第１半円領域６７ａと第２半円領域６７ｂに分けたときに、第１半円領域６７ａに配置される。第２ポート２２は、第２半円領域６７ｂに配置される。第３ポート２３は、第２半円領域６７ｂにおいて第２ポート２２よりも内周側に配置される。複数のピストン穴６９は、軸心７１を中心とした互いに異なる径の第１円９１及び第２円９２に沿って、当該２つの仮想円９１，９２の周方向に交互に配置されている。 As described above, the hydraulic pump 3 of the present embodiment includes a cylinder block 63, a plurality of pistons 65, and a valve plate 67. The cylinder block 63 is rotatably supported. A plurality of piston holes 69 are formed in the cylinder block 63 around the center of rotation axis. The piston 65 is attached to each of the plurality of piston holes 69. The valve plate 67 switches the oil passage connected to the piston hole 69 according to the rotation of the cylinder block 63. A first port 21, a second port 22, and a third port 23 are formed on the valve plate 67. The first port 21 is arranged in the first semicircular region 67a when the circular region around the rotation axis of the cylinder block 63 is divided into the first semicircular region 67a and the second semicircular region 67b. The second port 22 is arranged in the second semicircular region 67b. The third port 23 is arranged on the inner peripheral side of the second port 22 in the second semicircular region 67b. The plurality of piston holes 69 are alternately arranged in the circumferential direction of the two virtual circles 91 and 92 along the first circle 91 and the second circle 92 having different diameters about the axis 71.
　これにより、吸入量と吐出量が不等な油圧ポンプ３を実現することができる。また、第３ポート２３が第２ポート２２の内周側に位置することから、ピストン６５の吐出行程の途中及び吸入行程の途中では、ピストン穴６９に接続するポートが作動油の分流又は合流のために切り換わらない構成とすることができる。これにより、ピストン穴６９における作動油の吐出流量の変動を低減することができる。従って、油圧装置１で発生する騒音を低減することができるとともに、油圧装置１の作動に関する安定性を向上させることができる。また、外周側のピストン穴６９Ａと内周側のピストン穴６９Ｂとでピストン６５の往復ストロークが異なることを利用して、吸入量と吐出量の比のバリエーションを実現し易くなる。従って、設計の自由度が高くなり、様々な構成の油圧シリンダ５に容易に適合させることができる。 This makes it possible to realize a hydraulic pump 3 in which the suction amount and the discharge amount are unequal. Further, since the third port 23 is located on the inner peripheral side of the second port 22, the port connected to the piston hole 69 is divided or merged with the hydraulic oil during the discharge stroke and the suction stroke of the piston 65. Therefore, it can be configured so that it does not switch. As a result, fluctuations in the discharge flow rate of the hydraulic oil in the piston hole 69 can be reduced. Therefore, the noise generated by the hydraulic device 1 can be reduced, and the stability of the operation of the hydraulic device 1 can be improved. Further, by utilizing the fact that the reciprocating stroke of the piston 65 is different between the piston hole 69A on the outer peripheral side and the piston hole 69B on the inner peripheral side, it becomes easy to realize a variation in the ratio of the suction amount and the discharge amount. Therefore, the degree of freedom in design is increased, and it can be easily adapted to the hydraulic cylinder 5 having various configurations.
　また、本実施形態の油圧ポンプ３においては、外周側のピストン穴６９Ａの直径ｄ３と、内周側のピストン穴６９Ｂの直径ｄ４と、が異なる。 Further, in the hydraulic pump 3 of the present embodiment, the diameter d3 of the piston hole 69A on the outer peripheral side and the diameter d4 of the piston hole 69B on the inner peripheral side are different.
　これにより、外周側のピストン穴６９Ａと内周側のピストン穴６９Ｂとの間で、ピストン６５の往復ストロークによる作動油の吸入・吐出量の差を自由に付けることができる。従って、油圧ポンプ３の吸入量と吐出量の比の設計の自由度を、より高くすることができる。 As a result, the difference in the suction / discharge amount of hydraulic oil due to the reciprocating stroke of the piston 65 can be freely added between the piston hole 69A on the outer peripheral side and the piston hole 69B on the inner peripheral side. Therefore, the degree of freedom in designing the ratio of the suction amount and the discharge amount of the hydraulic pump 3 can be increased.
　また、本実施形態の油圧ポンプ３において、外周側のピストン穴６９Ａの直径ｄ３が、内周側のピストン穴の直径ｄ４よりも大きい。 Further, in the hydraulic pump 3 of the present embodiment, the diameter d3 of the piston hole 69A on the outer peripheral side is larger than the diameter d4 of the piston hole on the inner peripheral side.
　これにより、ピストン６５の往復ストロークの差とピストン穴６９の直径の差の相乗効果により、外周側のピストン穴６９Ａと内周側のピストン穴６９Ｂとの間で、作動油の吸入・吐出量の差を確保することができる。また、シリンダブロック６３において外周側に大径のピストン穴６９Ａを配置することで、シリンダブロック６３のスペースを効率的に利用することができる。この結果、シリンダブロック６３の小型化及び高容量化を実現できる。 As a result, due to the synergistic effect of the difference in the reciprocating stroke of the piston 65 and the difference in the diameter of the piston hole 69, the suction / discharge amount of hydraulic oil between the piston hole 69A on the outer peripheral side and the piston hole 69B on the inner peripheral side The difference can be secured. Further, by arranging the large-diameter piston hole 69A on the outer peripheral side of the cylinder block 63, the space of the cylinder block 63 can be efficiently used. As a result, the cylinder block 63 can be made smaller and have a higher capacity.
　また、本実施形態の油圧装置１は、油圧ポンプ３と、油圧シリンダ５と、を備える。油圧シリンダ５においてピストン３６により区画される圧力室のうち、ピストンロッド３７と反対側に位置するボトム室２５が、油圧ポンプ３の第１ポート２１に接続される。ピストンロッド３７と同じ側に位置するヘッド室２７が、油圧ポンプ３の第２ポート２２に接続される。 Further, the hydraulic device 1 of the present embodiment includes a hydraulic pump 3 and a hydraulic cylinder 5. Of the pressure chambers partitioned by the piston 36 in the hydraulic cylinder 5, the bottom chamber 25 located on the opposite side of the piston rod 37 is connected to the first port 21 of the hydraulic pump 3. The head chamber 27 located on the same side as the piston rod 37 is connected to the second port 22 of the hydraulic pump 3.
　これにより、ピストンロッド３７が単位長さだけ変位する場合に油圧シリンダ５のボトム室２５とヘッド室２７との間で容積変化が異なるのに合わせて、油圧ポンプ３から作動油を吸入及び吐出することができる。 As a result, when the piston rod 37 is displaced by a unit length, the hydraulic oil is sucked and discharged from the hydraulic pump 3 in accordance with the difference in volume change between the bottom chamber 25 and the head chamber 27 of the hydraulic cylinder 5. be able to.
　また、本実施形態の油圧装置１は、油圧ポンプ３と油圧シリンダ５との間で構成される閉回路に作動油を補充するための作動油供給部としてのチャージ回路３５を備える。油圧ポンプ３の第１ポート２１、第２ポート２２及び第３ポート２３のうち、油圧シリンダ５に接続されていない第３ポート２３が、チャージ回路３５と接続されている。 Further, the hydraulic device 1 of the present embodiment includes a charge circuit 35 as a hydraulic oil supply unit for replenishing the closed circuit formed between the hydraulic pump 3 and the hydraulic cylinder 5 with hydraulic oil. Of the first port 21, the second port 22, and the third port 23 of the hydraulic pump 3, the third port 23, which is not connected to the hydraulic cylinder 5, is connected to the charge circuit 35.
　これにより、チャージ回路３５をバッファとして利用して、油圧ポンプ３における吐出量と吸入量の差によって閉回路での作動油の量が変動するのに対応することができる。 As a result, the charge circuit 35 can be used as a buffer to cope with fluctuations in the amount of hydraulic oil in the closed circuit due to the difference between the discharge amount and the suction amount in the hydraulic pump 3.
　また、本実施形態の油圧装置１において、第３ポート２３には、チャージポンプ３９によって作動油を圧送するチャージ回路３５が接続される。 Further, in the hydraulic device 1 of the present embodiment, a charge circuit 35 for pumping hydraulic oil by a charge pump 39 is connected to the third port 23.
　これにより、油圧ポンプ３において第３ポート２３から作動油を吸入する場合、油圧ポンプ３を利用して、チャージ回路３５から作動油を閉回路へ供給することができる。また、油圧ポンプ３において第３ポート２３から作動油を吐出する場合、チャージ回路３５の圧力の補助となるので、その分、チャージポンプ３９として小容量のものを使用することができる。この結果、チャージポンプ３９のコストを低減することができる。 As a result, when the hydraulic pump 3 sucks the hydraulic oil from the third port 23, the hydraulic pump 3 can be used to supply the hydraulic oil from the charge circuit 35 to the closed circuit. Further, when the hydraulic pump 3 discharges the hydraulic oil from the third port 23, the pressure of the charge circuit 35 is assisted, so that a small capacity charge pump 39 can be used accordingly. As a result, the cost of the charge pump 39 can be reduced.
　次に、図６及び図７を参照して、第２実施形態を説明する。図６は、第２実施形態に係る油圧装置１ｘを示す図である。図７は、バルブプレート６７と油路板８５の構成を示す分解斜視断面図である。 Next, the second embodiment will be described with reference to FIGS. 6 and 7. FIG. 6 is a diagram showing a hydraulic device 1x according to the second embodiment. FIG. 7 is an exploded perspective sectional view showing the configuration of the valve plate 67 and the oil passage plate 85.
　本実施形態では、油圧ポンプ３の第３ポート２３が、チャージ回路３５のチャージ油路３３ではなく、図６に示すように、作動油供給部の作動油タンク１０２に供給油路１０１を介して接続されている。油圧ポンプ３の第３ポート２３は、作動油タンク１０２に対して作動油の吸入／吐出を行う。 In the present embodiment, the third port 23 of the hydraulic pump 3 is not the charge oil passage 33 of the charge circuit 35, but the hydraulic oil tank 102 of the hydraulic oil supply unit via the supply oil passage 101 as shown in FIG. It is connected. The third port 23 of the hydraulic pump 3 sucks / discharges the hydraulic oil to the hydraulic oil tank 102.
　チャージ回路３５が備えるチャージポンプ３９の吸入ポートは、作動油タンク１０２に接続されている。チャージポンプ３９は、油圧ポンプ３と並べて配置され、油圧ポンプ３と同じ電動モータ１０５により駆動される。 The suction port of the charge pump 39 included in the charge circuit 35 is connected to the hydraulic oil tank 102. The charge pump 39 is arranged side by side with the hydraulic pump 3 and is driven by the same electric motor 105 as the hydraulic pump 3.
　第３ポート２３と作動油タンク１０２とを接続する供給油路１０１の一部は、油圧ポンプ３のケーシング７０の内部に設けられ、残りは外部に設けられている。本実施形態において、供給油路１０１の一部は、図７に示すように、ケーシング７０に備えられた油路板８５の内部に形成されている。 A part of the supply oil passage 101 connecting the third port 23 and the hydraulic oil tank 102 is provided inside the casing 70 of the hydraulic pump 3, and the rest is provided outside. In the present embodiment, a part of the supply oil passage 101 is formed inside the oil passage plate 85 provided in the casing 70, as shown in FIG.
　油路板８５において、バルブプレート６７が取り付けられる側の面には、凹部１０７が形成されている。凹部１０７は、バルブプレート６７側に開口を形成している。 In the oil passage plate 85, a recess 107 is formed on the surface on the side where the valve plate 67 is attached. The recess 107 forms an opening on the valve plate 67 side.
　上述の軸心７１に沿って見たとき、凹部１０７の開口部は、円弧状の第３ポート２３より大きく、かつ第３ポート２３の全部を含む形状となっている。この凹部１０７が、供給油路１０１を介して、作動油タンク１０２と接続されている。 When viewed along the above-mentioned axis 71, the opening of the recess 107 is larger than the arc-shaped third port 23 and has a shape including the entire third port 23. The recess 107 is connected to the hydraulic oil tank 102 via the supply oil passage 101.
　本実施形態では、第３ポート２３に直接接続する凹部１０７の開口部が、第３ポート２３に対して広く形成されている。また、凹部１０７において開口部と底面との間の距離（凹部１０７の深さ）が、適宜確保されている。従って、油圧ポンプ３が作動油タンク１０２に対して、第３ポート２３を介して作動油を円滑に吸入／吐出することができる。具体的には、油圧ポンプ３において、第３ポート２３からの作動油の吸入時における自吸性能を向上させることができる。また、第３ポート２３からの作動油の吐出時における圧力損失を低減することができる。 In the present embodiment, the opening of the recess 107 directly connected to the third port 23 is formed wider than the third port 23. Further, in the recess 107, the distance between the opening and the bottom surface (depth of the recess 107) is appropriately secured. Therefore, the hydraulic pump 3 can smoothly suck / discharge the hydraulic oil to the hydraulic oil tank 102 via the third port 23. Specifically, in the hydraulic pump 3, the self-priming performance at the time of sucking the hydraulic oil from the third port 23 can be improved. Further, it is possible to reduce the pressure loss when the hydraulic oil is discharged from the third port 23.
　また、バルブプレート６７は、図８に示すように変更することもできる。図８は、バルブプレート６７の変形例を示す図である。図８の変形例では、バルブプレート６７において、第３ポート２３が、シャフト６１を差し込むための軸孔６２に連なるように形成される。第３ポート２３は軸孔６２に直接接続されており、第３ポート２３と軸孔６２とが一体となって１つの貫通孔を形成している。 The valve plate 67 can also be changed as shown in FIG. FIG. 8 is a diagram showing a modified example of the valve plate 67. In the modified example of FIG. 8, in the valve plate 67, the third port 23 is formed so as to be connected to the shaft hole 62 for inserting the shaft 61. The third port 23 is directly connected to the shaft hole 62, and the third port 23 and the shaft hole 62 are integrally formed to form one through hole.
　図８の変形例では、第１ポート２１が、複数の貫通孔２１ａから構成される。複数の貫通孔２１ａは、軸心７１を中心とした同一の円に沿って、周方向に所定間隔毎に並べて配置される。第２ポート２２が、複数の貫通孔２２ａから構成される。複数の貫通孔２２ａは、軸心７１を中心とした同一の円に沿って、周方向に所定間隔毎に並べて配置される。このように周方向に分割されたポートの構成は、第１ポート２１及び第２ポート２２の一方だけに適用されても良い。 In the modified example of FIG. 8, the first port 21 is composed of a plurality of through holes 21a. The plurality of through holes 21a are arranged side by side at predetermined intervals in the circumferential direction along the same circle centered on the axis 71. The second port 22 is composed of a plurality of through holes 22a. The plurality of through holes 22a are arranged side by side at predetermined intervals in the circumferential direction along the same circle centered on the axis 71. The configuration of the ports divided in the circumferential direction in this way may be applied to only one of the first port 21 and the second port 22.
　以上に説明したように、本実施形態の油圧装置１ｘにおいては、第３ポート２３は、油圧ポンプ３のケーシング７０の内部を介して、作動油タンク（作動油供給部）１０２と接続される。 As described above, in the hydraulic device 1x of the present embodiment, the third port 23 is connected to the hydraulic oil tank (hydraulic oil supply unit) 102 via the inside of the casing 70 of the hydraulic pump 3.
　これにより、第３ポート２３と作動油タンク１０２との接続構成の簡易化を図ることができる。 As a result, the connection configuration between the third port 23 and the hydraulic oil tank 102 can be simplified.
　また、本実施形態の油圧装置１ｘにおいては、油圧ポンプ３のケーシング７０は、バルブプレート６７と対向する油路板８５を備える。油路板８５には、バルブプレート６７側に開口する凹部１０７が形成される。シリンダブロック６３の回転軸心に沿って見たとき、凹部１０７の開口部は、第３ポート２３より大きく、かつ第３ポート２３の全部を含んでいる。第３ポート２３は、凹部１０７を介して作動油タンク１０２と接続されている。 Further, in the hydraulic device 1x of the present embodiment, the casing 70 of the hydraulic pump 3 includes an oil passage plate 85 facing the valve plate 67. The oil passage plate 85 is formed with a recess 107 that opens on the valve plate 67 side. When viewed along the rotation axis of the cylinder block 63, the opening of the recess 107 is larger than the third port 23 and includes the entire third port 23. The third port 23 is connected to the hydraulic oil tank 102 via the recess 107.
　これにより、作動油タンク１０２と第３ポート２３との間での作動油の流通が、油路板８５に形成されるとともに第３ポート２３に直接接続された広い凹部１０７を介して、円滑に行われる。従って、油圧ポンプ３において、第３ポート２３から作動油を吸入する場合の自吸性能を向上させることができる。また、第３ポート２３から作動油を吐出する場合の圧力損失を低減することができる。 As a result, the flow of hydraulic oil between the hydraulic oil tank 102 and the third port 23 is smoothly formed in the oil passage plate 85 and through the wide recess 107 directly connected to the third port 23. Will be done. Therefore, in the hydraulic pump 3, the self-priming performance when the hydraulic oil is sucked from the third port 23 can be improved. Further, it is possible to reduce the pressure loss when the hydraulic oil is discharged from the third port 23.
　以上に本発明の好適な実施の形態を説明したが、上記の構成は例えば以下のように変更することができる。 Although the preferred embodiment of the present invention has been described above, the above configuration can be changed as follows, for example.
　上記の実施形態では、油圧ポンプ３は、３個のポートを有するものであるが、これに限定されず、３以上の複数のポートを有するものであれば良い。 In the above embodiment, the hydraulic pump 3 has three ports, but the present invention is not limited to this, and any pump 3 may have three or more ports.
　ピストン穴６９Ａ及びピストン穴６９Ｂの数は、任意に変更することができる。例えば、外周側のピストン穴６９Ａを３つ、内周側のピストン穴６９Ｂを３つとすることができる。 The number of piston holes 69A and piston holes 69B can be changed arbitrarily. For example, the number of piston holes 69A on the outer peripheral side can be three, and the number of piston holes 69B on the inner peripheral side can be three.
　別の例では、外周側のピストン穴６９Ａを５つ、内周側のピストン穴６９Ｂを３つとすることができる。この場合、外周側の２つのピストン穴６９Ａと、内周側の１つのピストン穴とが、２つの仮想円の周方向に交互に配置されることになる。 In another example, the number of piston holes 69A on the outer peripheral side can be five, and the number of piston holes 69B on the inner peripheral side can be three. In this case, the two piston holes 69A on the outer peripheral side and the one piston hole on the inner peripheral side are alternately arranged in the circumferential direction of the two virtual circles.
　外周側のピストン穴６９Ａの直径ｄ３が、内周側のピストン穴６９Ｂの直径ｄ４と等しくても良い（ｄ３＝ｄ４）。この場合、外周側と内周側とでピストン６５を同一の構成とすることができるので、コストを低減することができる。外周側のピストン穴６９Ａの直径ｄ３が、内周側のピストン穴６９Ｂの直径ｄ４より小さくても良い（ｄ３＜ｄ４）。 The diameter d3 of the piston hole 69A on the outer peripheral side may be equal to the diameter d4 of the piston hole 69B on the inner peripheral side (d3 = d4). In this case, since the piston 65 can have the same configuration on the outer peripheral side and the inner peripheral side, the cost can be reduced. The diameter d3 of the piston hole 69A on the outer peripheral side may be smaller than the diameter d4 of the piston hole 69B on the inner peripheral side (d3 <d4).
　作動油供給部として、作動油を単に貯留する作動油タンクを、チャージ回路３５の代わりに油圧ポンプ３の第３ポート２３に接続することもできる。 As the hydraulic oil supply unit, a hydraulic oil tank that simply stores hydraulic oil can be connected to the third port 23 of the hydraulic pump 3 instead of the charge circuit 35.
　チャージ油路３３を第２ポート２２に接続し、第２油路３２（ヘッド室２７）を第３ポート２３に接続しても良い。 The charge oil passage 33 may be connected to the second port 22, and the second oil passage 32 (head chamber 27) may be connected to the third port 23.
　油圧サーボ機構１３は、チャージ回路３５のチャージポンプ３９とは異なる油圧ポンプによって駆動されても良い。 The hydraulic servo mechanism 13 may be driven by a hydraulic pump different from the charge pump 39 of the charge circuit 35.
　上記の実施形態では、油圧ポンプ３の吐出方向の制御は可動斜板１１の傾斜方向の変更により行われるが、これに限定されない。例えば、シャフト６１の回転方向を切り換えることで、油圧ポンプ３の吸入／吐出を切り換えても良い。 In the above embodiment, the discharge direction of the hydraulic pump 3 is controlled by changing the inclination direction of the movable swash plate 11, but the present invention is not limited to this. For example, the suction / discharge of the hydraulic pump 3 may be switched by switching the rotation direction of the shaft 61.
　可動斜板１１の傾斜角度を、例えば電動モータによって変更しても良い。 The tilt angle of the movable swash plate 11 may be changed by, for example, an electric motor.
　油圧ポンプ３及びチャージポンプ３９のうち少なくとも何れかを、電動モータとは異なる駆動源（例えば、エンジン）によって駆動するように構成することもできる。 At least one of the hydraulic pump 3 and the charge pump 39 can be configured to be driven by a drive source (for example, an engine) different from that of the electric motor.
　上述の教示を考慮すれば、本発明が多くの変更形態及び変形形態をとり得ることは明らかである。従って、本発明が、添付の特許請求の範囲内において、本明細書に記載された以外の方法で実施され得ることを理解されたい。 Considering the above teachings, it is clear that the present invention can take many modified and modified forms. Therefore, it should be understood that the present invention may be practiced in ways other than those described herein, within the scope of the appended claims.
　１　油圧装置
　３　油圧ポンプ
　５　油圧シリンダ
　１３　油圧サーボ機構（油圧駆動機構）
　２１　第１ポート
　２２　第２ポート
　２３　第３ポート
　２５　ボトム室
　２７　ヘッド室
　３５　チャージ回路（作動油供給部）
　３９　チャージポンプ
　６１　シャフト
　６３　シリンダブロック
　６５　ピストン
　６７　バルブプレート
　６７ａ　第１半円領域
　６７ｂ　第２半円領域
　６９　ピストン穴
　６９Ａ　外周側のピストン穴
　６９Ｂ　内周側のピストン穴
　７０　ケーシング
　８５　油路板（油路部材）
　９１　第１円（仮想円）
　９２　第２円（仮想円）
　１０２　作動油タンク（作動油供給部）
　１０７　凹部
　ｄ３　外周側のピストン穴の直径
　ｄ４　内周側のピストン穴の直径 1 Hydraulic device 3 Hydraulic pump 5 Hydraulic cylinder 13 Hydraulic servo mechanism (hydraulic drive mechanism)
21 1st port 22 2nd port 23 3rd port 25 Bottom chamber 27 Head chamber 35 Charge circuit (hydraulic oil supply unit)
39 Charge pump 61 Shaft 63 Cylinder block 65 Piston 67 Valve plate 67a 1st semicircular area 67b 2nd semicircular area 69 Piston hole 69A Outer peripheral side piston hole 69B Inner peripheral side piston hole 70 Casing 85 Oil passage plate (oil passage) Element)
91 1st yen (virtual circle)
92 Second Yen (Virtual Circle)
102 Hydraulic oil tank (hydraulic oil supply unit)
107 Recess d3 Diameter of piston hole on the outer circumference side d4 Diameter of piston hole on the inner circumference side

Claims (8)

  1. 　回転可能に支持され、複数のピストン穴が回転軸心まわりに設けられるシリンダブロックと、
    　前記複数のピストン穴のそれぞれに取り付けられる複数のピストンと、
    　前記ピストン穴に接続される油路を前記シリンダブロックの回転に応じて切り換えるバルブプレートと、
    を備え、
    　前記バルブプレートには、
    　前記シリンダブロックの回転軸心の周囲の円形の領域を第１半円領域と第２半円領域に分けたときに、前記第１半円領域に配置される第１ポートと、
    　前記第２半円領域に配置される第２ポートと、
    　前記第２半円領域において前記第２ポートよりも内周側に配置される第３ポートと、
    が形成され、
    　前記複数のピストン穴は、前記回転軸心を中心とした互いに異なる径の２つの仮想円に沿って、当該２つの仮想円の周方向に交互に配置されることを特徴とする油圧ポンプ。     A cylinder block that is rotatably supported and has multiple piston holes around the center of rotation.
    A plurality of pistons attached to each of the plurality of piston holes,
    A valve plate that switches the oil passage connected to the piston hole according to the rotation of the cylinder block.
    With
    The valve plate has
    When the circular region around the rotation axis of the cylinder block is divided into a first semicircular region and a second semicircular region, the first port arranged in the first semicircular region and
    The second port arranged in the second semicircular region and
    A third port arranged on the inner peripheral side of the second port in the second semicircular region,
    Is formed,
    A hydraulic pump characterized in that the plurality of piston holes are alternately arranged in the circumferential direction of the two virtual circles along two virtual circles having different diameters about the center of rotation.
  2. 　請求項１に記載の油圧ポンプであって、
    　外周側に配置される前記ピストン穴の直径と、内周側に配置される前記ピストン穴の直径、が異なることを特徴とする油圧ポンプ。     The hydraulic pump according to claim 1.
    A hydraulic pump characterized in that the diameter of the piston hole arranged on the outer peripheral side and the diameter of the piston hole arranged on the inner peripheral side are different.
  3. 　請求項２に記載の油圧ポンプであって、
    　外周側に配置される前記ピストン穴の直径が、内周側に配置される前記ピストン穴の直径よりも大きいことを特徴とする油圧ポンプ。     The hydraulic pump according to claim 2.
    A hydraulic pump characterized in that the diameter of the piston hole arranged on the outer peripheral side is larger than the diameter of the piston hole arranged on the inner peripheral side.
  4. 　請求項１から３までの何れか一項に記載の油圧ポンプと、
    　油圧シリンダと、
    を備え、
    　前記油圧シリンダにおいてピストンにより区画される圧力室のうち、ピストンロッドと反対側に位置する圧力室が、前記第１ポートに接続され、
    　前記ピストンロッドと同じ側に位置する圧力室が、前記第２ポート又は前記第３ポートに接続されることを特徴とする油圧装置。     The hydraulic pump according to any one of claims 1 to 3 and
    Hydraulic cylinder and
    With
    Of the pressure chambers partitioned by the piston in the hydraulic cylinder, the pressure chamber located on the side opposite to the piston rod is connected to the first port.
    A hydraulic device characterized in that a pressure chamber located on the same side as the piston rod is connected to the second port or the third port.
  5. 　請求項４に記載の油圧装置であって、
    　前記油圧ポンプと前記油圧シリンダとの間で構成される閉回路に作動油を補充するための作動油供給部を備え、
    　前記第１ポート、前記第２ポート及び前記第３ポートのうち、前記油圧シリンダに接続されたポート以外のポートが、前記作動油供給部と接続されていることを特徴とする油圧装置。     The hydraulic device according to claim 4.
    The closed circuit formed between the hydraulic pump and the hydraulic cylinder is provided with a hydraulic oil supply unit for replenishing hydraulic oil.
    A hydraulic device characterized in that, of the first port, the second port, and the third port, ports other than the port connected to the hydraulic cylinder are connected to the hydraulic oil supply unit.
  6. 　請求項５に記載の油圧装置であって、
    　前記第１ポート、前記第２ポート及び前記第３ポートのうち、前記油圧シリンダに接続されたポート以外のポートは、前記油圧ポンプのケーシングの内部を介して、前記作動油供給部と接続されていることを特徴とする油圧装置。     The hydraulic device according to claim 5.
    Of the first port, the second port, and the third port, ports other than the port connected to the hydraulic cylinder are connected to the hydraulic oil supply unit via the inside of the casing of the hydraulic pump. A hydraulic system characterized by being present.
  7. 　請求項６に記載の油圧装置であって、
    　前記油圧ポンプのケーシングは、前記バルブプレートと対向する油路部材を備え、
    　前記油路部材には、前記バルブプレート側に開口する凹部が形成され、
    　前記シリンダブロックの回転軸心に沿って見たとき、前記凹部の開口部は、前記第３ポートより大きく、かつ前記第３ポートの全部を含んでおり、
    　前記第３ポートが、前記凹部を介して、前記作動油供給部と接続されていることを特徴とする油圧装置。     The hydraulic device according to claim 6.
    The casing of the hydraulic pump includes an oil passage member facing the valve plate.
    The oil passage member is formed with a recess that opens on the valve plate side.
    When viewed along the rotation axis of the cylinder block, the opening of the recess is larger than the third port and includes the entire third port.
    A hydraulic device characterized in that the third port is connected to the hydraulic oil supply unit via the recess.
  8. 　請求項５から７までの何れか一項に記載の油圧装置であって、
    　前記作動油供給部が、チャージポンプによって作動油を圧送するチャージ回路であることを特徴とする油圧装置。     The hydraulic device according to any one of claims 5 to 7.
    A hydraulic device characterized in that the hydraulic oil supply unit is a charge circuit for pumping hydraulic oil by a charge pump.
PCT/JP2020/028150 2019-07-31 2020-07-20 Hydraulic pump and hydraulic device WO2021020217A1 (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5578707U (en) * 1978-11-24 1980-05-30
WO1998017913A1 (en) * 1996-10-24 1998-04-30 Komatsu Ltd. Hydraulic pump/motor apparatus
JPH10184532A (en) * 1996-12-26 1998-07-14 Daikin Ind Ltd Variable displacement piston pump
JP2009121435A (en) * 2007-11-19 2009-06-04 Yanmar Co Ltd Axial piston device, hydraulic circuit and working machine
JP2011017317A (en) * 2009-07-10 2011-01-27 Kanzaki Kokyukoki Manufacturing Co Ltd Pump for closed-circuit configuration

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5578767U (en) * 1978-11-27 1980-05-30

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5578707U (en) * 1978-11-24 1980-05-30
WO1998017913A1 (en) * 1996-10-24 1998-04-30 Komatsu Ltd. Hydraulic pump/motor apparatus
JPH10184532A (en) * 1996-12-26 1998-07-14 Daikin Ind Ltd Variable displacement piston pump
JP2009121435A (en) * 2007-11-19 2009-06-04 Yanmar Co Ltd Axial piston device, hydraulic circuit and working machine
JP2011017317A (en) * 2009-07-10 2011-01-27 Kanzaki Kokyukoki Manufacturing Co Ltd Pump for closed-circuit configuration

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