JP5480096B2 - Swash plate type piston pump motor - Google Patents

Description

  The present invention relates to a swash plate type piston pump motor used in various industrial machines.

  In the swash plate type piston pump / motor, as the cylinder block rotates, a plurality of pistons slide in contact with the swash plate via shoes, and the volume chambers are expanded and contracted by each piston.

  Conventionally, as this type of swash plate type piston pump / motor, there is a type in which a disc-shaped swash plate is accommodated at the bottom of the case and a rotation prevention pin is provided as means for locking the rotation of the swash plate with respect to the case ( (See Patent Documents 1 and 2).

  In this case, a hole is formed in each of the case and the swash plate, and the rotation prevention pin is inserted over each hole, so that the rotation of the swash plate with respect to the case is locked.

JP-A-5-231300 Japanese National Patent Publication No. 8-50083

  However, in such a conventional swash plate type piston pump / motor, since it is necessary to interpose a rotation-preventing pin between the case and the swash plate, the number of parts and assembly man-hours increase. Further, since it is necessary to form holes for inserting the rotation prevention pins in each of the case and the swash plate, the number of processing steps for the case and the swash plate is increased, resulting in an increase in the cost of the product.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a swash plate type piston pump motor that can simplify the structure.

  The present invention relates to a swash plate type piston pump motor in which a piston slides against a swash plate as the cylinder block rotates and reciprocates, and a volume chamber expands and contracts by the piston. And a notch is formed in the outer peripheral portion of the swash plate, and a notch portion is formed on the swash plate accommodating portion so as to face the notch. Is configured such that the rotation of the swash plate is locked by contacting the locking surface.

  According to the present invention, in the piston pump, the piston side frictional force acts on the swash plate as the cylinder block rotates, but the notch abuts the locking surface, and the reaction force causes the swash plate to rotate. Locked.

  As a result, the piston pump does not need to be provided with a non-rotating pin for locking the rotation of the swash plate as in the conventional device, and the number of parts, assembly man-hours and processing man-hours are reduced, and the cost of the product can be reduced.

Sectional drawing of the piston pump which shows embodiment of this invention. The front view of a cylinder block similarly. Similarly, a front view of the valve plate. Similarly, a sectional view and a front view of a swash plate. Similarly, a sectional view and a front view of the case.

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

  As shown in FIG. 1, the rotary swash plate type hydraulic piston pump 10 has a cylinder block 3 and a swash plate (thrust plate) 40 housed in an internal space formed by a case 30 and a port block 2.

  A shaft 5 that supports the cylinder block 3 is provided. The shaft 5 passes through the cylinder block 3, and the middle thereof is supported by the case 30 via the bearing 11, and one end thereof is supported by the port block 2 via the bearing 12.

  The rotation of the shaft 5 is transmitted from a power source (not shown) to one end of the shaft 5 that projects outward from the case 30. The cylinder block 3 is rotationally driven via the shaft 5.

  A plurality of cylinders 6 are formed in the cylinder block 3, and pistons 8 are inserted into the respective cylinders 6, and a volume chamber 7 is defined therebetween.

  Each cylinder 6 extends in parallel with the rotation axis O of the cylinder block 3 and is arranged on the same circumference with the rotation axis O as a center at a constant interval.

  One end of each piston 8 protrudes from the cylinder block 3, and a shoe 9 is rotatably connected. However, the present invention is not limited to this, and the shoe 9 may be formed integrally with the piston 8.

  A coiled spring 16 and a plurality of pins 17 are accommodated inside the cylinder block 3. Each pin 17 protrudes from the end face of the cylinder block 3 due to the urging force of the spring, and each shoe 9 via a hemispherical retainer holder 18 with which each pin 17 abuts and a disk-shaped retainer plate 19 with which the retainer holder 18 is in sliding contact. Is pressed against the swash plate 40.

  When the piston pump 10 is operated, the hydraulic oil from the volume chamber 7 is supplied between the shoe 9 and the swash plate 40 through the through hole 21 of the piston 8 and the through hole 22 of the shoe 9. It is supported in a floating manner on the sliding contact surface 41 (see FIG. 4) via a hydraulic oil film.

  When the cylinder block 3 rotates during the operation of the piston pump 10, each piston 8 reciprocates in contact with the swash plate 40 via the shoe 9 slidably contacting the swash plate 40, thereby expanding and contracting the volume chamber 7 of the cylinder 6. . As the cylinder block 3 rotates in one direction, the suction stroke for expanding the volume chamber 7 by the piston 8 and the discharge stroke for contracting the volume chamber 7 are repeated.

  As shown in FIG. 2, cylinder ports 13 communicating with the respective volume chambers 7 are opened on the end surface of the cylinder block 3 side by side on a circumference around the rotation axis O.

  The case 30 is provided with a valve plate 15 slidably contacting the end face of the cylinder block 3.

  As shown in FIG. 3, an arcuate suction port 25 and a plurality of discharge ports 24 are opened in the valve plate 15 side by side on the circumference centering on the rotation axis O.

  The cylinder block 3 rotates in the direction indicated by the arrow in FIG. Each piston 8 reaches a top dead center and a bottom dead center whose sliding direction is switched at a position facing the center line C of the valve plate 15. The piston pump 10 is divided into a suction area A and a discharge area B by a center line C. The sliding contact surface 20 of the valve plate 15 with respect to the cylinder block 3 is also divided into a suction area A and a discharge area B by a center line C. A suction port 25 is opened in the suction area A, and a discharge port 24 is opened in the discharge area B. ing.

  When the cylinder block 3 rotates, each cylinder port 13 communicates with the suction port 25 and the discharge port 24, and the supply and discharge (suction and discharge) of hydraulic oil to and from each volume chamber 7 is controlled.

  More specifically, in the suction area A, each piston 8 expands the volume chamber 7 as the cylinder block 3 rotates, and hydraulic oil from a tank (not shown) is connected to a pipe (not shown), a suction passage, and a suction port 25. It passes through the cylinder port 13 and is sucked into each volume chamber 7.

  As the cylinder block 3 rotates in the discharge region B, the piston 8 contracts the volume chamber 7, and the pressurized hydraulic oil discharged from the volume chamber 7 passes through the discharge port 24, the discharge passage, and piping (not shown) to the hydraulic equipment. It is guided.

  4A is a cross-sectional view of the swash plate 40, and FIG. 4B is a front view of the swash plate 40. The swash plate 40 is formed in a disk shape, and a hole 46 through which the shaft 5 passes is opened at the center thereof.

  The disc-shaped swash plate 40 includes a sliding contact surface 41 that is in sliding contact with the shoe 9, a back surface 42 that is in contact with the case 30, and a cylindrical outer peripheral surface 43.

  5A is a cross-sectional view of the case 30, and FIG. 5B is a front view showing the bottom of the case 30. A swash plate housing portion 31 into which the swash plate 40 is fitted is formed at the bottom of the case 30.

  The swash plate accommodating portion 31 has a cylindrical side surface 32 and a planar bottom surface 33, and thereby defines a disk-shaped space that is recessed in the bottom of the case 30. A hole 36 through which the shaft 5 passes is opened at the center of the bottom surface 33.

  The swash plate accommodating portion 31 is formed so as to have a predetermined gap between the swash plate 40. In a state where the swash plate 40, the spring 16, the pin 17, the retainer holder 18, the retainer plate 19, the shoe 9, the piston 8, the cylinder block 3, etc. are assembled to the case 30, the swash plate 40 is moved by the urging force of the spring 16. The swash plate accommodating portion 31 is pressed against the swash plate accommodating portion 31 so that the swash plate accommodating portion 31 does not fall off.

  As a gist of the present invention, first and second cutout portions 44 and 45 are formed on the outer peripheral portion of the swash plate 40 as means for locking the rotation of the swash plate 40 with respect to the case 30. On the other hand, first and second locking surfaces 34 and 35 that face the first and second cutout portions 44 and 45 of the swash plate 40 are formed in the swash plate accommodating portion 31 of the case 30.

  When the cylinder block 3 is rotationally driven via the shaft 5 during the operation of the piston pump 10, each piston 8 reciprocates following the swash plate 40 via the shoe 9 slidably contacting the swash plate 40. The six volume chambers 7 are expanded and contracted. The swash plate 40 works in a direction in which the frictional force of the shoe 9 is rotated about the rotation axis O when the shoe 9 is in sliding contact, but the first and second cutout portions 44 and 45 are accommodated in the swash plate. The first and second locking surfaces 34 and 35 of the portion 31 are brought into contact with each other, and the rotation of the case 31 with respect to the case 30 is locked.

  The first and second cutout portions 44 and 45 formed on the outer peripheral portion of the swash plate 40 have a shape obtained by cutting out the cylindrical outer peripheral surface 43 into a flat shape.

  The first and second cutout portions 44 and 45 are arranged so that the extended lines along the respective end faces are substantially orthogonal to each other.

  The sizes of the first and second cutout portions 44 and 45 are different, and the distance L1 of the first cutout portion 44 with respect to the rotation axis O is larger than the distance L2 of the second cutout portion 45. .

  When the piston pump 10 is assembled, the swash plate 40 is assembled such that the back surface 42 abuts the bottom surface 33 of the swash plate housing 31 and the sliding contact surface 41 faces the shoe 9. When the sizes of the first and second cutout portions 44 and 45 are different, when the piston pump 10 is assembled, the orientation of the back and front where the swash plate 40 is assembled to the swash plate accommodating portion 31 is limited. It is avoided that the rear surface 42 of the swash plate 40 is assembled so as to face the shoe 9.

  The first and second locking surfaces 34, 35 of the swash plate accommodating portion 31 are formed in a similar shape to the first and second cutout portions 44, 45 of the swash plate 40, and the first and second notches It is formed in a planar shape extending in parallel to the notches 44 and 45.

  The swash plate accommodating portion 31 is divided into a suction area A and a discharge area B by a center line C as shown by hatching in FIG.

  The first and second cutout portions 44 and 45 of the swash plate 40 and the first and second locking surfaces 34 and 35 of the swash plate housing portion 31 are provided in the discharge region B and provided in the suction region A. I can't.

  When the piston pump 10 is operated, the oil pressure in the volume chamber 7 contracted by the piston 8 in the discharge region B is higher than the oil pressure in the volume chamber 7 expanded by the piston 8 in the suction region A. However, the force that presses the shoe 9 against the swash plate 40 is greater in the discharge region B than in the suction region A, so the frictional force that the shoe 9 applies to the swash plate 40 is greater in the discharge region B than in the suction region A.

  Because of the configuration in which the first and second cutout portions 44 and 45 and the first and second locking surfaces 34 and 35 are disposed in the discharge region B where the frictional force applied to the swash plate 40 by the shoe 9 increases. The first and second cutout portions 44 and 45 and the first and second locking surfaces 34 and 35 are arranged in the suction region A where the frictional force applied to the swash plate 40 by the shoe 9 is reduced. In comparison, the distance between the point of action of the friction force acting on the swash plate 40 and the point of reaction of the reaction force that locks the rotation is shortened, so that deformation of the swash plate 40 can be suppressed, and the swash plate 40 can be fixed. Surely done. As a result, the rigidity required for the swash plate 40 is reduced, and the thickness of the swash plate 40 can be reduced.

  The metal swash plate 40 is made of, for example, a steel material and is formed by pressing.

  The first and second cutout portions 44 and 45 are integrally formed in the step of pressing the swash plate 40.

  After the swash plate 40 is pressed, the sliding contact surface 41 is polished. Thereby, the surface of the sliding contact surface 41 is smaller than that of the back surface 42.

  The metal case 30 is made of, for example, an aluminum alloy and is cast by a die casting method using a mold. After the case 30 is cast, the swash plate accommodating portion 31 and the hole 35 are formed by cutting.

  The first and second locking surfaces 34 and 35 are integrally formed in the process of cutting the swash plate housing 31. Cutting of the first and second locking surfaces 34 and 35 is automatically formed continuously with the swash plate housing 31 based on a program set in the cutting machine. Thereby, by providing the first and second locking surfaces 34 and 35, the number of steps for cutting the swash plate accommodating portion 31 does not increase.

  As described above, in the present embodiment, with the piston pump 10 in which the piston 8 reciprocates in sliding contact with the swash plate 40 via the shoe 9 as the cylinder block 3 rotates, the volume chamber 7 expands and contracts by the piston 8. The disk-like swash plate 40 and the swash plate accommodating portion 31 into which the swash plate 40 is fitted are provided, and notches 44 and 45 are formed on the outer periphery of the swash plate 40, while the swash plate Locking surfaces 34 and 35 that face the notches 44 and 45 are formed in the accommodating portion 31.

  Based on the above configuration, in the piston pump 10, the frictional force on the piston 8 side (the shoe 9) acts on the swash plate 40 with the rotation of the cylinder block 3, but the notches 44 and 45 have the locking surfaces 34 and 35. Or it contacts the vicinity and rotation of the swash plate 40 is latched by the reaction force.

  As a result, the piston pump 10 does not need to be provided with a non-rotating pin for locking the rotation of the swash plate 40 as in the conventional device, and the number of parts, processing man-hours and assembly man-hours are reduced, and the cost of the product can be reduced. .

  In this embodiment, the swash plate 40 is formed with at least first and second cutout portions 44 and 45, and the sizes of the first and second cutout portions 44 and 45 are different from each other. The first and second locking surfaces 34 and 35 that face the first and second cutout portions 44 and 45 are formed in the structure 31.

  Based on the above configuration, when the piston pump 10 is assembled, the direction of the back and front where the swash plate 40 is assembled with respect to the swash plate accommodating portion 31 is limited, and the rear surface 42 of the swash plate 40 is assembled so as to face the shoe 9. Is avoided.

  In the present embodiment, the swash plate accommodating portion 31 is a piston pump 10 that is divided into a suction area A in which the volume chamber 7 is expanded by the piston 8 and a discharge area B in which the volume chamber 7 is contracted by the piston 8. The engaging surfaces 34 and 35 are arranged in the discharge region B.

  Based on the above configuration, the distance between the point of action of the frictional force acting on the swash plate 40 and the point of action of the reaction force that locks the rotation is shortened, and the swash plate 40 is fixed securely.

  The present invention can be applied not only to the fixed displacement type piston pump 10 in which the swash plate 40 is fixed to the case 30 but also to a variable displacement type piston pump in which the swash plate is swingably provided in the case.

  Moreover, this invention is applicable not only to a piston pump but the piston motor driven with the supplied working fluid.

  The working fluid supplied to and discharged from the piston pump / motor is not limited to hydraulic oil (oil), and for example, a water-soluble alternative liquid may be used.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

3 Cylinder block 7 Volume chamber
8 Piston
9 Shoe 10 Piston pump
30 cases
31 Swash plate housing portion 34, 35 Locking surface 40 Swash plate 44, 45 Notch

Claims (3)

As the cylinder block rotates, the piston slides against the swash plate via the shoe and reciprocates.
A swash plate type piston pump motor whose volume chamber is expanded and contracted by the piston,
The disk-shaped swash plate;
A swash plate housing portion into which the swash plate is fitted,
While a notch is formed on the outer periphery of the swash plate,
The swash plate type piston pump / motor is characterized in that a locking surface is formed in the swash plate housing portion to face the notch. The swash plate is formed with at least first and second notches,
The size of the first and second notches is different,
2. The swash plate type piston pump motor according to claim 1, wherein the swash plate accommodating portion is formed with first and second engaging surfaces facing the first and second cutout portions. The swash plate housing is
A suction region in which the volume chamber is expanded by the piston;
The volume chamber is divided into a discharge region contracted by the piston,
The swash plate type piston pump motor according to claim 1, wherein the locking surface is disposed in the discharge region.

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