JP2015071978A - Swash plate type piston pump motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a swash plate type piston pump motor that can prevent floating of a shoe during high speed rotation and suppress decline in pump efficiency during low speed rotation.SOLUTION: A swash plate type piston pump motor 100 includes: a retainer holder 50 slidably fitted to a rotating shaft 1 and having one end coming into sliding contact with a retainer 40; an energizing member 60 for energizing the retainer holder 50 on the retainer side; an annular recessed portion 15 that is formed in a cylinder block 10 to surround the outer periphery of the rotating shaft 1 and to which the other end side of the retainer holder 50 is inserted; and a movable member 80 that abuts on both of a bottom surface 15A of the annular recessed portion 15 and the other end surface 52 of the retainer holder 50 and is movable in the radial direction within the annular recessed portion 15 by using centrifugal force caused by the rotation of the cylinder block 10. Conversion portion 52, 15A for converting the force of the movable member 80 toward the radial outer side to the energizing force for energizing the retainer holder 50 on the retainer side are formed at least one of the retainer holder 50 and the annular recessed portion 15.

Description

  The present invention relates to a swash plate type piston pump motor.

  In Patent Document 1, a rotating shaft, a cylinder block fixed to the rotating shaft and having a plurality of cylinders, a piston disposed in each cylinder, a shoe rotatably provided at one end of the piston, A swash plate type piston pump including a swash plate on which a shoe slides as the cylinder block rotates is disclosed. When the rotating shaft is driven and the cylinder block rotates, each piston reciprocates with a stroke amount corresponding to the inclination angle of the swash plate, and the volume chamber defined in the cylinder expands and contracts.

  The swash plate type piston pump described above further includes a retainer plate that holds all the shoes provided for each piston, a retainer holder that is in sliding contact with the center of the retainer plate, and a spring that biases the retainer holder toward the retainer plate. I have.

JP 2001-107842 A

  In such a swash plate type piston pump, the urging force of the spring that urges the retainer holder is such that the shoe can be prevented from floating from the swash plate due to the pulling resistance of the piston or the centrifugal force acting on the shoe. Is set to the value of

  In order to prevent the shoe from lifting regardless of the rotational speed of the piston pump, it is necessary to set the biasing force of the spring in accordance with the high-speed rotation that requires a high pressing force. However, if the spring urging force is set in accordance with the high speed rotation, the spring urging force becomes excessive at the low speed rotation, and the sliding frictional force between the shoe and the swash plate increases, resulting in a decrease in pump efficiency. .

  Accordingly, the present invention has been made in view of the above-described problems, and a swash plate type piston pump motor that can prevent the shoe from being lifted during high-speed rotation and can suppress reduction in pump efficiency during low-speed rotation. The purpose is to provide.

  A swash plate type piston pump motor according to the present invention is fixed to a rotating shaft, and has a cylinder block having a plurality of cylinders arranged at predetermined intervals around the rotating shaft, and is slidably inserted into the cylinder. A piston defining a volume chamber inside the cylinder, a shoe rotatably connected to a tip of the piston, a swash plate on which the shoe slides as the rotating shaft rotates, An annular retainer that holds all the shoes provided for each piston, a retainer holder that is slidably mounted in the axial direction with respect to the outer periphery of the rotating shaft, and whose one end is in sliding contact with the central portion of the retainer; An urging member that urges the retainer holder toward the retainer so as to press the shoe against the swash plate, and a cylinder block that surrounds the outer periphery of the rotating shaft. Formed in the annular recess into which the other end of the retainer holder is inserted, the bottom surface of the annular recess and the other end surface of the retainer holder, and the inside of the annular recess by the centrifugal force accompanying the rotation of the cylinder block. A movable member movable in the radial direction. At least one of the retainer holder and the annular recess is formed with a conversion portion that converts the force of the movable member toward the radially outer side into a biasing force that biases the retainer holder toward the retainer.

  According to the present invention, when the rotation speed of the cylinder block is low, the retainer holder is biased mainly by the biasing force of the biasing member, and the retainer is pressed toward the swash plate. On the other hand, when the rotational speed of the cylinder block increases, the movable member moves radially outward by centrifugal force, and the force of the movable member radially outward presses the rear end surface of the retainer holder in the axial direction by the conversion unit. It is converted into power to do. The retainer holder is biased by the biasing force of the biasing member and the pressing force acting on the rear end surface, and the retainer is pressed toward the swash plate. Thus, in the swash plate type piston pump / motor, the urging force for urging the retainer holder can be changed according to the rotational speed of the cylinder block. As a result, the pressing force can be increased during high-speed rotation to prevent the shoe from lifting from the swash plate, and the pressing force can be set to a lower value during low-speed rotation, so the sliding friction force between the shoe and the swash plate It is possible to suppress a decrease in pump efficiency by reducing

It is sectional drawing of the swash plate type piston pump motor by 1st Embodiment of this invention. It is an enlarged view of the retainer holder periphery of a swash plate type piston pump motor. It is an enlarged view of the retainer holder periphery of the swash plate type piston pump motor by 2nd Embodiment of this invention. It is the figure which looked at the cylinder block of a swash plate type piston pump motor from the opening end side.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

(First embodiment)
FIG. 1 is a sectional view of a swash plate type piston pump motor 100 according to the first embodiment.

  The swash plate type piston pump / motor 100 functions as a piston pump capable of supplying a working fluid by rotating the rotating shaft 1 and reciprocating the piston 2 by power from outside, and the working fluid supplied from the outside. The piston 2 reciprocates due to the fluid pressure and the rotating shaft 1 rotates, thereby functioning as a piston motor capable of outputting a rotational driving force. In the swash plate type piston pump motor 100, water, oil, other alternative liquids, etc. are used as the working fluid.

  In the following, a case where the swash plate type piston pump / motor 100 is caused to function as a piston pump will be exemplified, and the swash plate type piston pump / motor 100 is simply referred to as “piston pump 100”.

  Piston pump 100 is mounted on a vehicle such as a construction machine. The piston pump 100 supplies the working fluid to an actuator or the like when the rotating shaft 1 is rotationally driven by the power of an engine (not shown) installed in the vehicle.

  The piston pump 100 includes a cylindrical case 3, end blocks 4 and 5 provided so as to close openings at both ends of the case 3, and a rotary shaft 1 rotatably supported by the end blocks 4 and 5. And a cylinder block 10 housed in a housing chamber 6 defined by the case 3 and the end blocks 4 and 5.

  The rotating shaft 1 is a shaft member, and is rotationally driven based on the power of an engine provided in the vehicle. The rotating shaft 1 is provided so as to pass through the insertion hole 5 </ b> A of the end block 5, and the rear end portion of the rotating shaft 1 is inserted into a recess 4 </ b> A formed in the end block 4. The tip of the rotary shaft 1 protrudes from the end block 5 to the outside, and engine power is transmitted to the tip.

  The rotary shaft 1 is rotatably supported by front end side bearings 7A and 7B provided in the insertion hole 5A of the end block 5 and a rear end side bearing 8 provided in the recess 4A of the end block 4. The end block 4 is formed with a suction port 4B for guiding working fluid sucked into the volume chamber 13 described later and a discharge port 4C for guiding working fluid discharged from the volume chamber 13.

  The cylinder block 10 is a bottomed cylindrical member and is rotatably provided in the storage chamber 6. The cylinder block 10 includes an insertion portion 11 having an insertion hole 11A through which the rotation shaft 1 is inserted, and the rotation shaft 1 and the insertion hole 11A of the insertion portion 11 are spline-coupled. Thus, since the cylinder block 10 is fixed to the rotating shaft 1, the cylinder block 10 rotates in synchronization with the rotation of the rotating shaft 1.

  The cylinder block 10 includes a plurality of cylinders 12 extending in parallel with the rotation shaft 1. These cylinders 12 are arranged at a constant interval on the same circumference centered on the axis of the rotary shaft 1. A piston 2 that is a columnar member is inserted into the cylinder 12 so as to freely reciprocate. By inserting the piston 2 into the cylinder 12, a volume chamber 13 is defined in the cylinder 12.

  The piston pump 100 holds a shoe 20 that is rotatably connected to the tip of each piston 2, a swash plate 30 on which the shoe 20 slides as the rotary shaft 1 rotates, and all the shoes 20. A retainer plate 40 and a retainer holder 50 that is in sliding contact with the retainer plate 40 are provided.

  The shoe 20 includes a circular flat plate portion 21 that slides on the swash plate 30, and a receiving portion 22 that is integrally formed with the flat plate portion 21 and receives the spherical seat 2 </ b> A formed at the tip of the piston 2. The inner surface of the receiving portion 22 is formed in a spherical shape, and slides with respect to the outer surface of the spherical seat 2 </ b> A of the piston 2. Thus, the shoe 20 is configured to be angularly displaceable with respect to the spherical seat 2A of the piston 2.

  The swash plate 30 is fixed to the inner end surface of the end block 4, and has a sliding contact surface 31 that is inclined with respect to a direction orthogonal to the rotation shaft 1. The flat plate portion 21 of the shoe 20 connected to the piston 2 is disposed so as to be in surface contact with the sliding contact surface 31 of the swash plate 30.

  In the piston pump 100, the swash plate 30 is fixed to the end block 5 so that the tilt angle (tilt angle) of the swash plate 30 is constant. However, the swash plate 30 can be adjusted so that the tilt angle can be adjusted. May be slidably disposed in the storage chamber 6.

  The retainer plate 40 (retainer) is formed as an annular flat plate member. The retainer plate 40 has a plurality of insertion holes 41 formed at predetermined intervals in the circumferential direction. The retainer plate 40 holds all the shoes 20 provided at the tip of each piston 2 on the same plane in a state where the receiving portion 22 of the shoe 20 is inserted into the insertion hole 41.

  The retainer holder 50 is a cylindrical member that is attached to the outer periphery of the rotary shaft 1 and is slidable in the axial direction along the rotary shaft 1. The retainer holder 50 is disposed such that the tip thereof is in sliding contact with the center portion of the retainer plate 40.

  An annular recess 15 is formed at the distal end portion of the insertion portion 11 of the cylinder block 10 so as to surround the outer periphery of the rotating shaft 1, and the rear end side of the retainer holder 50 is inserted into the annular recess 15. The retainer holder 50 not only slides on the outer peripheral surface of the rotary shaft 1 but also slides on the inner peripheral surface of the annular recess 15.

  A flange portion 51 protruding outward in the radial direction is formed at a substantially central position in the axial direction of the retainer holder 50. The flange portion 51 is provided along the outer periphery of the retainer holder 50. A compressed spring 60 is interposed between the flange portion 51 of the retainer holder 50 and the distal end surface of the insertion portion 11 of the cylinder block 10. The spring 60 is a biasing member that biases the retainer holder 50 toward the retainer plate 40. The retainer holder 50 biased in this way presses the retainer plate 40 toward the swash plate 30, whereby the shoe 20 is pressed against the swash plate 30.

  A valve plate 70 with which the end face of the cylinder block 10 is in sliding contact is fixed to the end block 4 that closes the open end of the case 3. The valve plate 70 communicates with a suction port 4B of the end block 4 and communicates with a suction hole 71 serving as a supply / discharge passage communicating with the volume chamber 13 of the cylinder block 10 and a discharge port 4C of the end block 4 and with the cylinder block. Discharge holes 72 communicating with the ten volume chambers 13 are formed.

  In the piston pump 100 configured as described above, when the rotary shaft 1 is rotationally driven by the power of the engine and the cylinder block 10 rotates, the flat plate portion 21 of each shoe 20 slides with respect to the swash plate 30, and each piston 2 reciprocates along the cylinder 12 with a stroke amount corresponding to the tilt angle of the swash plate 30. The volume of each volume chamber 13 is increased or decreased by the reciprocation of each piston 2.

  The volume chamber 13 that is enlarged by the rotation of the cylinder block 10 includes a suction port 4B of the end block 4, a suction hole 71 of the valve plate 70, and a through hole formed in the bottom of the cylinder block 10 corresponding to each volume chamber 13. The working fluid is drawn through 14. On the other hand, the working fluid is discharged from the volume chamber 13 that is reduced by the rotation of the cylinder block 10 through the through hole 14 of the cylinder block 10, the discharge hole 72 of the valve plate 70, and the discharge port 4 </ b> C of the end block 4. Thus, in the piston pump 100, the working fluid is continuously sucked and discharged as the cylinder block 10 rotates.

  In the piston pump 100, in order to stably suck and discharge the working fluid as the rotating shaft 1 and the cylinder block 10 rotate, the flat plate portion 21 of the shoe 20 connected to the piston 2 is always slid on the swash plate 30. It is necessary to slide with respect to the swash plate 30 in surface contact with the contact surface 31.

  In the conventional piston pump, when the rotational speed of the rotary shaft increases and the high speed rotation state is reached, the pulling resistance of the piston in the region where the volume chamber expands, the centrifugal force acting on the shoe, etc., increase, and the shoe comes off the swash plate. There is a risk of floating. When the shoe is lifted off the swash plate, the expansion / contraction of the volume chamber becomes insufficient, and the discharge flow rate decreases. In order to prevent the shoe from being lifted regardless of the rotational speed of the shaft, it is necessary to set a biasing force of a spring that biases the retainer holder in accordance with a high-speed rotation that requires a high pressing force. However, if the spring urging force is set in accordance with the high speed rotation, the spring urging force becomes excessive at the low speed rotation, and the sliding frictional force between the shoe and the swash plate increases, resulting in a decrease in pump efficiency. .

  Therefore, in the piston pump 100 according to the present embodiment, the urging force of the spring 60 that urges the retainer holder 50 is set to the urging force required when the rotating shaft 1 rotates at a low speed. Further, the piston pump 100 includes a movable member 80 that applies a biasing force to the retainer holder 50 according to the rotational speed of the cylinder block 10.

  As shown in FIGS. 1 and 2, the movable member 80 is a spherical weight and is accommodated in a space defined between the annular recess 15 of the cylinder block 10 and the retainer holder 50. The movable members 80 are arranged one by one along the outer periphery of the rotating shaft 1. The outer diameter of the movable member 80 is set smaller than the distance between the inner peripheral surface of the annular recess 15 and the outer peripheral surface of the rotary shaft 1. In the present embodiment, a plurality of movable members 80 are provided, but the number of movable members 80 is arbitrarily set as necessary.

  As shown in FIG. 2, each movable member 80 provided in the annular recess 15 is disposed so as to contact both the bottom surface 15 </ b> A of the annular recess 15 and the rear end surface 52 of the retainer holder 50. A bottom surface 15 </ b> A of the annular recess 15 is formed as a flat surface extending in the radial direction of the rotating shaft 1, and a rear end surface 52 of the retainer holder 50 is formed as an inclined surface inclined with respect to the radial direction of the rotating shaft 1. ing. The rear end surface 52 of the retainer holder 50 is an inclined surface that is inclined so as to approach the bottom surface 15A of the annular recess 15 toward the radially outer side. As described above, the rear end surface 15A of the retainer holder 50 has a conical shape.

  Since the movable member 80 and the bottom surface 15A of the annular recess 15 are in contact with each other, when the cylinder block 10 rotates, the movable member 80 also rotates about the axis of the rotating shaft 1 as a rotation center. When the movable member 80 rotates in this way, a centrifugal force acts on the movable member 80, and the movable member 80 moves radially outward as indicated by an arrow A1 in FIG. That is, the movable member 80 is configured to move in the radial direction in the annular recess 15 by the centrifugal force accompanying the rotation of the cylinder block 10.

  When the movable member 80 moves from the radially inner side to the outer side by the action of centrifugal force with the movable member 80 in contact with the rear end surface 52 of the retainer holder 50 formed as an inclined surface, the retainer holder is moved by the movable member 80. 50 is pushed out to the retainer plate 40 side (swash plate 30 side) as shown by arrow A2. As described above, the rear end surface 52 of the retainer holder 50 formed as an inclined surface converts the force (centrifugal force) of the movable member 80 toward the radially outer side into a biasing force that biases the retainer holder 50 toward the retainer plate 40. It functions as a conversion unit for conversion.

  The urging force acting on the retainer holder 50 by the movable member 80 moving radially outward changes in accordance with the rotational speed of the rotary shaft 1 and the cylinder block 10 which is correlated with the rotational speed of the movable member 80, and rotates. The higher the rotational speed of the shaft 1 and the cylinder block 10, the larger it becomes. Thus, the retainer holder 50 attaches the retainer plate 40 not only to urge the retainer plate 40 by receiving the reaction force of the spring 60 but also to be pushed out by the movable member 80 that moves by receiving the centrifugal force. Rush.

  In the piston pump 100 configured as described above, when the rotational speed of the rotary shaft 1 and the cylinder block 10 is low, the retainer holder 50 is biased mainly by the biasing force of the spring 60, and the retainer plate 40 is swash plate. It is pressed to the 30 side. On the other hand, when the rotational speed of the rotating shaft 1 and the cylinder block 10 is high, the biasing force of the spring 60 and the pressing force acting on the rear end surface 52 of the retainer holder 50 when the movable member 80 moves radially outward. The retainer holder 50 is biased, and the retainer plate 40 is pressed toward the swash plate 30 side.

  As described above, in the piston pump 100, the pressing force of the shoe 20 against the swash plate 30 increases from the value defined in advance by the biasing force of the spring 60 as the rotational speed of the rotary shaft 1 and the cylinder block 10 increases. Go. Accordingly, a decrease in pump efficiency is suppressed by a predetermined pressing force during low-speed rotation, and the shoe 20 is prevented from being lifted by a high pressing force during high-speed rotation.

  According to the piston pump 100 of the first embodiment described above, the following effects can be obtained.

  The piston pump 100 abuts both the spring 60 that urges the retainer holder 50 toward the retainer plate 40, the bottom surface 15 </ b> A of the annular recess 15 of the cylinder block 10, and the rear end surface 52 of the retainer holder 50. And a movable member 80 that is movable in the radial direction within the annular recess 15 by the centrifugal force associated therewith. The rear end surface 52 of the retainer holder 50 is formed as an inclined surface (converting portion) that converts a force of the movable member 80 toward the radially outer side into a biasing force that biases the retainer holder 50 toward the retainer plate 40. When the rotational speeds of the rotary shaft 1 and the cylinder block 10 are low, the retainer holder 50 is biased mainly by the biasing force of the spring 60, and the retainer plate 40 is pressed toward the swash plate 30 side. On the other hand, when the rotational speed of the rotating shaft 1 and the cylinder block 10 increases, the rear end surface 52 of the retainer holder 50 that contacts the movable member 80 is moved in the axial direction by moving the movable member 80 radially outward by centrifugal force. The retainer holder 50 is urged by the pressing force acting on the rear end surface 52 and the urging force of the spring 60, and the retainer plate 40 is pressed toward the swash plate 30. Thus, in the piston pump 100, the urging force that urges the retainer holder 50 can be changed according to the rotational speed of the cylinder block 10.

  Therefore, in the piston pump 100, the pressing force can be increased during high-speed rotation to prevent the shoe 20 from lifting from the swash plate 30, and the pressing force can be reduced during low-speed rotation to reduce the contact between the shoe 20 and the swash plate 30. By reducing the sliding frictional force, it is possible to suppress a decrease in pump efficiency.

  Since the biasing force of the spring 60 that biases the retainer holder 50 is set to a predetermined biasing force required when the rotating shaft 1 rotates at a low speed, the rotating speed of the rotating shaft 1 and the cylinder block 10 is low, and the movable member. Even when a sufficient centrifugal force does not act on 80, the retainer holder 50 can be pressed against the retainer plate 40 by the biasing force of the spring 60. Therefore, it is possible to prevent the shoe 20 from being lifted even during low-speed rotation.

  Thus, since the spring 60 is set to a predetermined urging force required at the time of low speed rotation, the spring 60 can be reduced in size, and the piston pump 100 can be reduced in size and weight.

(Second Embodiment)
Next, a piston pump motor 100 according to a second embodiment of the present invention will be described with reference to FIG. In FIG. 3, the same reference numerals as those in the first embodiment are assigned to members having the same functions as those in the first embodiment. In the following, a case where the swash plate type piston pump / motor 100 is caused to function as a piston pump will be exemplified, and the swash plate type piston pump / motor 100 is simply referred to as “piston pump 100”.

  In the piston pump 100 according to the second embodiment, the rear end surface 52 of the retainer holder 50 is formed as a flat surface extending in the radial direction of the rotary shaft 1, and an annular recess formed in the insertion portion 11 of the cylinder block 10. The bottom surface 15 </ b> A of 15 is formed as an inclined surface that is inclined with respect to the radial direction of the rotary shaft 1. The bottom surface 15 </ b> A of the annular recess 15 is an inclined surface that is inclined so as to approach the rear end surface 52 of the retainer holder 50 toward the radially outer side. As described above, the bottom surface 15A of the annular recess 15 has a conical shape.

  Each movable member 80 provided in the annular recess 15 is disposed so as to contact both the bottom surface 15 </ b> A of the annular recess 15 and the rear end surface 52 of the retainer holder 50. Further, the outer diameter of the movable member 80 is set smaller than the distance between the inner peripheral surface of the annular recess 15 and the outer peripheral surface of the rotary shaft 1.

  Since the movable member 80 and the bottom surface 15A of the annular recess 15 are in contact with each other, when the cylinder block 10 rotates, the movable member 80 also rotates about the axis of the rotating shaft 1 as a rotation center. When the movable member 80 rotates in this way, a centrifugal force acts on the movable member 80, and the movable member 80 moves radially outward as indicated by an arrow A1 in FIG.

  When centrifugal force acts on the movable member 80, the movable member 80 moves from the radially inner side to the outer side and moves in the axial direction (right side in FIG. 3) along the bottom surface 15A (inclined surface) of the annular recess 15. . The rear end surface 52 of the retainer holder 50 is pushed in the axial direction by the movable member 80 moving in this way, and the retainer holder 50 is pushed out to the retainer plate 40 side (swash plate 30 side) as shown by an arrow A2. Thus, the bottom surface 15A of the annular recess 15 formed as an inclined surface converts the force (centrifugal force) of the movable member 80 toward the radially outer side into a biasing force that biases the retainer holder 50 toward the retainer plate 40. Functions as a conversion unit.

  In the piston pump 100 according to the second embodiment, when the rotational speeds of the rotary shaft 1 and the cylinder block 10 are low, the retainer holder 50 is biased mainly by the biasing force of the spring 60, and the retainer plate 40 is moved to the swash plate 30 side. Pressed. On the other hand, when the rotational speed of the rotating shaft 1 and the cylinder block 10 is increased, the movable member 80 moves radially outward along the bottom surface 15A of the annular recess 15 by centrifugal force, so that the retainer holder 50 that contacts the movable member 80 is moved. The rear end face 52 is pushed in the axial direction, the retainer holder 50 is urged by the pressing force acting on the rear end face 52 and the urging force of the spring 60, and the retainer plate 40 is pushed toward the swash plate 30 side.

  Accordingly, the pressing force can be increased during high-speed rotation to prevent the shoe 20 from being lifted from the swash plate 30, and a decrease in pump efficiency can be suppressed by the predetermined pressing force during low-speed rotation.

  The embodiment of the present invention has been described above. However, the above embodiment is merely one example of application of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

  In the first and second embodiments, since the movable member 80 and the bottom surface 15A of the annular recess 15 are in contact with each other, the movable member 80 also rotates when the cylinder block 10 rotates. That is, a frictional resistance is generated between the movable member 80 and the bottom surface 15 </ b> A of the annular recess 15, and the movable member 80 rotates so as to be rotated by the cylinder block 10 by the action of this frictional resistance. Therefore, the higher the rotational speed of the cylinder block 10 is, the higher the rotational speed of the movable member 80 is. However, the rotational speed of the cylinder block 10 and the rotational speed of the movable member 80 do not always coincide with each other. The rotational speed of the movable member 80 may be lower than the rotational speed. In order to make the rotational speed of the cylinder block 10 and the rotational speed of the movable member 80 coincide with each other, a guide groove 15B that guides the movement of the movable member 80 in the radial direction is formed on the bottom surface 15A of the annular recess 15 as shown in FIG. May be.

  The guide groove 15 </ b> B is a groove that extends straight along the radial direction of the rotary shaft 1, and is recessed on the bottom surface 15 </ b> A of the annular recess 15. The groove depth of the guide groove 15B is set smaller than the diameter of the movable member 80. Therefore, in a state where the movable member 80 is disposed in the guide groove 15B, a part of the movable member 80 protrudes from the guide groove 15B and abuts on the rear end surface 52 of the retainer holder 50.

  As shown in FIG. 4, the guide groove 15B is formed on the bottom surface 15A of the annular recess 15, and the movable member 80 is disposed in the guide groove 15B. Therefore, when the cylinder block 10 rotates, the movable member 80 is disposed in the guide groove 15B. In this state, the rotating shaft 1 is rotated. As a result, the rotational speed of the cylinder block 10 matches the rotational speed of the movable member 80. Thus, by making both rotational speed correspond, desired centrifugal force can be made to act on the movable member 80 according to the rotational speed of the rotating shaft 1 and the cylinder block 10, and the dispersion | variation in the urging | biasing force of the retainer holder 50 can be made. It becomes possible to reduce.

  In FIG. 4, a total of four guide grooves 15B are formed on the bottom surface 15A of the annular recess 15, and these guide grooves 15B are arranged every 90 ° in the circumferential direction. However, the number and positions of the guide grooves 15B are as required. It can be set freely. Further, the number of movable members 80 is also set corresponding to the number of guide grooves 15B.

  In the first embodiment described above, the bottom surface 15A of the annular recess 15 of the cylinder block 10 is formed as a flat surface, but may be formed as an inclined surface as in the second embodiment. In the second embodiment, the rear end surface 52 of the retainer holder 50 is formed as a flat surface, but may be formed as an inclined surface as in the first embodiment.

  Furthermore, in the first and second embodiments, the spring 60 is interposed between the flange portion 51 of the retainer holder 50 and the distal end surface of the insertion portion 11 of the cylinder block 10, but in place of the spring 60, the retainer An urging member such as rubber capable of urging the holder 50 may be interposed.

  Furthermore, in the first and second embodiments, the movable member 80 is formed in a spherical shape, but any shape can be used as long as it is a member that can be moved in the radial direction by the centrifugal force accompanying the rotation of the cylinder block 10. It may be. For example, the movable member 80 is formed as a wedge-shaped member or a ring member formed by connecting a plurality of arc-shaped members in the circumferential direction so as to come into surface contact with the rear end surface 52 of the retainer holder 50 and the bottom surface 15A of the annular recess 15. Is done.

  The inclination angle of the rear end surface 52 of the retainer holder 50 of the first embodiment and the bottom surface 15A of the annular recess 15 of the second embodiment is set to a constant angle, but the inclination angle is stepwise or continuous along the radial direction. May be changed. By changing the inclination angle in this way, it is possible to adjust the urging force acting on the retainer holder 50 to a desired characteristic by moving the movable member 80 radially outward.

  In the first and second embodiments, the space in which the movable member 80 is accommodated may be filled with a working fluid such as water or oil. By filling the liquid in this way, it is possible to reduce the impact force when the movable member 80 collides with the outer peripheral surface of the rotating shaft 1 or the inner peripheral surface of the annular recess 15. Thereby, generation | occurrence | production of a collision sound can be suppressed and durability of the movable member 80, the rotating shaft 1, the cylinder block 10, etc. can be improved.

  Furthermore, in the first and second embodiments, the movable member 80 is positioned at the initial position where it contacts the outer peripheral surface of the rotating shaft 1 when the rotating shaft 1 is stopped or when the rotating shaft 1 is rotating at a very low speed. An elastic member that pushes the retainer holder 50 back in the axial direction may be provided.

  Further, in the first and second embodiments, the case where the swash plate type piston pump / motor 100 is caused to function as a piston pump is exemplified, but the swash plate type piston pump / motor 100 may be made to function as a piston motor capable of outputting a rotational driving force. Even in the case of functioning as a piston motor, the urging force of the retainer holder 50 can be increased during high-speed rotation to prevent the shoe 20 from being lifted from the swash plate 30. On the other hand, at the time of low-speed rotation, a decrease in pump efficiency can be suppressed by reducing the urging force of the retainer holder 50.

DESCRIPTION OF SYMBOLS 100 Swash plate type piston pump motor 1 Rotating shaft 2 Piston 10 Cylinder block 12 Cylinder 13 Volume chamber 15 Annular recessed part 15A Bottom face (conversion part)
15B Guide groove 20 Shoe 30 Swash plate 40 Retainer plate (Retainer)
50 Retainer holder 51 Flange part 52 Rear end face (conversion part)
60 Spring (biasing member)
80 Movable members

Claims (3)

A cylinder block having a plurality of cylinders fixed to the rotary shaft and arranged at predetermined intervals around the rotary shaft;
A piston that is slidably inserted into the cylinder and defines a volume chamber in the cylinder;
A shoe rotatably connected to the tip of the piston;
A swash plate on which the shoe slides as the rotating shaft rotates;
An annular retainer for holding all the shoes provided for each piston;
A retainer holder, which is slidably mounted in the axial direction with respect to the outer periphery of the rotating shaft, and whose one end is in sliding contact with the central portion of the retainer;
A biasing member that biases the retainer holder toward the retainer so as to press the shoe against the swash plate;
An annular recess formed in the cylinder block so as to surround the outer periphery of the rotating shaft and into which the other end of the retainer holder is inserted;
A movable member that abuts both the bottom surface of the annular recess and the other end surface of the retainer holder, and is movable in the radial direction within the annular recess by a centrifugal force accompanying rotation of the cylinder block;
At least one of the retainer holder and the annular recess is formed with a conversion portion that converts a force of the movable member toward the radially outer side into a biasing force that biases the retainer holder toward the retainer.
Swash plate type piston pump motor. The converter is an inclined surface formed on the other end surface of the retainer holder,
The inclined surface is inclined so as to approach the bottom surface of the annular recess toward the outer side in the radial direction.
The swash plate type piston pump motor according to claim 1. A guide groove for guiding the movement of the movable member in the radial direction is formed on the bottom surface of the annular recess.
The swash plate type piston pump motor according to claim 1 or 2.

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