Hydraulic axial piston pump / motor with a valve plate with optimized opening shapes of the fluid connections and a residual pressure relief opening in the transfer area to form a rotational support area and a residual pressure release area

Abstract

Hydraulic axial pump / motor, wherein a cylinder block (6) with a plurality of cylinder bores (25) formed about an axis of rotation (C) slides with respect to a valve plate (7) which has a high-pressure port (PB2) and a low-pressure port (PB1) and controls the reversal of a piston in each of the cylinder bores (25) depending on the inclination (a) of a swashplate (3), wherein an opening shape of the high-pressure port (PB2) and an opening shape of the low-pressure port (PB1) extend circumferentially on the same arc centered about the axis of rotation (C) and are annular band shapes having no top dead center and bottom dead center, and an opening shape of a cylinder port (25P) in each of the cylinder bores (25) extends circumferentially on the same arc where the high-pressure port (PB2) and the low-pressure port (PB1) are arranged, and is an annular band shape.which does not communicate with the high-pressure port (PB2) and the low-pressure port (PB1), at least when it is positioned at top dead center and bottom dead center, an opening shape of an end part on a front side of the cylinder opening (25P) and an opening shape of an end part on a rear side of the cylinder opening (25P) with respect to a direction of rotation of the cylinder block (6) have circular convex shapes, an opening shape of an end part on a front side of the low-pressure port (PB1) in the direction of rotation of the cylinder block (6) is a circular convex shape, an opening shape of an end part on a rear side of the low-pressure port (PB1) in the direction of rotation of the cylinder block (6) is a circular concave shape,The opening shape of the end part on the front of the cylinder opening (25P) in the direction of rotation of the cylinder opening (25P) and the opening shape of the end part on the rear of the low-pressure port (PB1) in the direction of rotation of the cylinder block (6) have essentially the same corresponding shape, wherein the valve disc (7) further comprises a residual pressure relief port (30) which enables communication between the cylinder bore (25), via the cylinder opening (25P), via the residual pressure relief port (30), via a flow path (L1), via a working oil reservoir (T), via a flow path (L) with the low-pressure port (PB1), wherein the residual pressure relief port (30) is provided in a region within a rotational movement range (E) of the cylinder opening (25P) and near top dead center up to the valve disc intake port of the low-pressure port (PB1).and to describe the position of the cylinder opening (25P), the respective vertex of the following angles θ (θ0, θ1, θ2) is formed by the intersection of the axis of rotation (C) of the shaft (1) with the axis between bottom dead center and top dead center, the latter axis also being the reference axis for the respective angle θ. (&THgr;0, &THgr;1, &THgr;2) represents, and for the cylinder opening (25P), in a range starting from a position where the center of the cylinder opening (25P) is at top dead center, that is, a position where the end part of the front of the cylinder opening (25P) is at an angle θ0 in the direction of rotation, up to a position with an angle θ1 (θ1 > θ0), where the end part of the front of the cylinder opening (25P) first communicates with the residual pressure relief opening (30),The rotation of the cylinder block (6) is supported by pressurized working oil inside the cylinder bore (25), this area representing the specifically designed, relatively large rotation support area (ΔΔΔ1), and in the aforementioned angular range Δ0 to Δ1 there is no fluid connection between the cylinder opening (25P) and the residual pressure relief opening (30) as well as the low-pressure port (PB1), and in the course of further rotation, the end part of the front of the cylinder opening (25P) communicates with the residual pressure relief opening (30) from angle Δ1 to angle Δ2 (Δ2 > Δ1), and this in turn communicates with the low-pressure port (PB1), thereby reducing the pressure in the cylinder bore (25), the angular range Δ1 to Δ2 representing the residual pressure relief area (ΔΔΔ2).in which the fluid connection between the cylinder opening (25P) and the low-pressure port (PB1) only occurs via the residual pressure relief port (30), and in the course of further rotational movement, for angles ΔH greater than ΔH, for the end part of the front of the cylinder opening (25P), a suction process occurs, i.e., a direct fluid connection between the cylinder opening (25P) and the low-pressure port (PB1).

Description

Area

[0001] The present invention relates to an axial-type hydraulic pump / motor (hydraulic pump or hydraulic motor) in which a cylinder block with a plurality of cylinder bores formed around an axis of rotation slides relative to a valve disc, which has a high-pressure port and a low-pressure port and controls the reversal of a piston in each of the cylinder bores depending on the inclination of a swashplate. In particular, the present invention relates to a hydraulic pump / motor that can suppress a reduction in suction power while increasing rotational assistance power due to residual pressure inside a cylinder bore when transitioning from a discharge process (high-pressure process) to a suction process (low-pressure process). Background

[0002] In many cases, a hydraulic axial piston pump driven by a power engine and a hydraulic axial piston motor driven by a high-pressure working oil are commonly used, for example in construction machinery.

[0003] For example, the hydraulic axial piston pump comprises a cylinder block, a plurality of pistons, and a valve plate. The cylinder block is designed to rotate integrally with a rotary shaft, which is rotatably mounted inside a housing and is configured with a plurality of cylinders spaced apart circumferentially and extending axially. Each piston is slidably mounted within its corresponding cylinder of the cylinder block and draws in / discharges working oil by axial movement in accordance with the rotation of the cylinder block. The valve plate is located between the housing and an end face of the cylinder block and is configured with an intake port and a discharge port that communicate with each of the cylinders.In a hydraulic pump, when a drive shaft is set in motion, the cylinder block rotates together with a working shaft within the housing, and each piston moves back and forth in its corresponding cylinder of the cylinder block. The working oil, drawn into the cylinders from the intake port, is pressurized by the pistons and discharged from the discharge port as high-pressure working oil.

[0004] When the cylinder port of each cylinder communicates with the intake port of the valve head, an intake stroke occurs. During the intake stroke, the pistons move out of the cylinders between the starting and ending edges of the intake port, drawing the working oil from the intake port into the cylinder. Conversely, when the cylinder port of each cylinder communicates with the discharge port, an exhaust stroke occurs. During the exhaust stroke, the pistons move inward between the starting and ending edges of the discharge port, expelling the working oil from the cylinders to the discharge port. By rotating the cylinder block so that the intake and discharge strokes are repeated, the working oil drawn into the cylinders from the intake port is pressurized during the intake stroke and discharged to the discharge port during the exhaust stroke. Objections from patent literature

[0005] Patent literature 1: Japanese published patent publication no. 2000-64950 Brief description of the technical problem

[0006] In the conventional hydraulic pump or similar described above, the pressure inside the cylinders, from which the working oil was discharged via the discharge opening of the valve plate during the discharge process, is high.

[0007] Therefore, for example, patent literature 1 provides a residual pressure extraction port, causing the high-pressure working oil inside the cylinders to flow back to the intake port when transitioning from the discharge to the intake process. As a result, the change in working oil pressure from discharge to intake is small, ensuring that the working oil pressure inside the cylinder and the working oil pressure inside the intake port are equal when the cylinder port communicates with the intake port.

[0008] However, during the transition from the discharge to the intake process, in a case where the residual pressure inside the cylinder is high, the rotation of the cylinder block is assisted, thus improving rotational efficiency. Therefore, it is preferred that the rotational assistance zone, extending from top dead center to the residual pressure extraction port with which the cylinder port communicates, be increased in length with respect to rotational torque efficiency. However, increasing the length of the rotational assistance zone shifts an end portion on the side of the intake port's top dead center towards the side of a bottom dead center. As a result, the intake start time, at which the cylinder port communicates with the intake port, is delayed, and the duration of the overall intake process is shortened; therefore, the suction efficiency during the intake process is reduced.

[0009] The present invention is made with regard to the above, and an object thereof is the provision of a hydraulic pump / motor that can suppress a reduction in suction power while increasing the rotational support power due to residual pressure inside a cylinder bore during the transition from a discharge to a suction process. Solution to the problem

[0010] To solve the problem described above and to achieve the objective, a hydraulic pump / motor according to the present invention is a hydraulic axial pump / motor in which a cylinder block with a plurality of cylinder bores formed around an axis of rotation slides with respect to a valve disc that has a high-pressure port and a low-pressure port and controls the reversal of a piston in each of the cylinder bores depending on the inclination of a swashplate. Furthermore, the opening shapes of the high-pressure port and the low-pressure port extend circumferentially on the same arc centered around the axis of rotation and are annular band shapes that have no top dead center and no bottom dead center, wherein an opening shape of a cylinder port in each of the cylinder bores is located on the same arc where the high-pressure port and the low-pressure port are arranged.extending circumferentially and having an annular band shape that does not communicate with the high-pressure port and the low-pressure port, at least when positioned at top dead center and bottom dead center, and wherein, based on the direction of rotation of the cylinder block: an opening shape of an end part on the front in the direction of rotation of the cylinder opening and an opening shape of an end part on the rear in the direction of rotation of the low-pressure port partially have the same shape; and / or an opening shape of an end part on the rear in the direction of rotation of the cylinder opening and an opening shape of an end part on the front in the direction of rotation of the low-pressure port partially have the same shape.

[0011] Furthermore, in the hydraulic pump / motor according to the present invention, in the above invention, the opening shape of the end part on the front in the direction of rotation of the cylinder opening and the opening shape of the end part on the back in the direction of rotation of the low-pressure port have the same shape, and / or the opening shape of the end part on the back in the direction of rotation of the cylinder opening and the opening shape of the end part on the front in the direction of rotation of the low-pressure port have the same shape.

[0012] Furthermore, in the hydraulic pump / motor according to the present invention, in the above invention, the opening shape of the end part on the front in the direction of rotation of the cylinder opening and an opening shape of an end part on the back in the direction of rotation of the high-pressure port have partially the same shape, and / or the opening shape of the end part on the back in the direction of rotation of the cylinder opening and an opening shape of an end part on the front in the direction of rotation of the high-pressure port have partially the same shape.

[0013] Furthermore, in the hydraulic pump / motor according to the present invention, in the above invention, the opening shape of the end part on the front in the direction of rotation of the cylinder opening and the opening shape of the end part on the back in the direction of rotation of the high-pressure port have the same shape, and / or the opening shape of the end part on the back in the direction of rotation of the cylinder opening and the opening shape of the end part on the front in the direction of rotation of the high-pressure port have the same shape.

[0014] Furthermore, the hydraulic pump / motor according to the present invention, in the above invention, further comprises a residual pressure relief opening which is provided on the valve plate and communicates with the cylinder bore on the side of the top dead center before the cylinder bore on the side of the top dead center communicates with the low pressure port.Furthermore, an opening portion of the end part on the rear side is separated from the top dead center in the rotational direction of the low-pressure port, so that it communicates with an opening portion of the end part on the front side in the rotational direction of the cylinder opening, after the opening portion of the end part on the front side in the rotational direction of the cylinder opening passes through a rotation support zone, where the rotation of the cylinder block is supported by pressurized oil inside the cylinder bore from a top dead center position of the cylinder opening, and a residual pressure relief zone, where the pressure inside the cylinder bore is reduced by the communication between the residual pressure relief port and the cylinder bore, and transitions to a suction process.

[0015] Furthermore, in the hydraulic pump / motor according to the present invention, in the above invention, at least one opening part of the end part on the front in the direction of rotation of the low-pressure port, an opening part of the end part on the back in the direction of rotation of the high-pressure port, and an opening part of the end part on the front in the direction of rotation of the high-pressure port are formed at a position that does not communicate with the cylinder opening, only when the cylinder opening is positioned at top dead center or bottom dead center.

[0016] Furthermore, in the hydraulic pump / motor according to the present invention, in the above invention, the opening shape of the cylinder opening is a cocoon-like annular band shape, in which the end parts on the front and the back form arcs in the direction of rotation.

[0017] Furthermore, in the hydraulic pump / motor according to the present invention, in the above invention, the opening shapes of the high-pressure port and the low-pressure port are cocoon-like annular band shapes in which the end parts on the front and the back form arcs in the directions of rotation.

[0018] Furthermore, the hydraulic pump / motor according to the present invention is a hydraulic axial pump / motor in which a cylinder block with a plurality of cylinder bores formed around an axis of rotation slides with respect to a valve disc, which has a high-pressure port and a low-pressure port and controls the reversal of a piston in each of the cylinder bores depending on the inclination of a swashplate. Furthermore, the opening shapes of the high-pressure port and the low-pressure port extend circumferentially on the same arc centered around the axis of rotation and are annular band shapes that have no top dead center and no bottom dead center. An opening shape of a cylinder port in each of the cylinder bores extends circumferentially on the same arc where the high-pressure port and the low-pressure port are arranged and is an annular band shape.which does not communicate with the high-pressure port and the low-pressure port, at least when positioned at top dead center and bottom dead center, and based on the direction of rotation of the cylinder block: opening shapes of the end parts on the front and rear in the direction of rotation of the cylinder opening are circular convex shapes; opening shapes of the end parts on the front and rear in the direction of rotation of the high-pressure port and an opening shape of an end part on the front in the direction of rotation of the low-pressure port are circular convex shapes; , The opening shape of an end part on the rear side in the direction of rotation of the low-pressure port is a circular concave shape; and the opening shape of the end part on the front side in the direction of rotation of the cylinder opening and the opening shape of the end part on the rear side in the direction of rotation of the low-pressure port have the same shape.

[0019] Furthermore, the hydraulic pump / motor according to the present invention is a hydraulic axial pump / motor, wherein a cylinder block with a plurality of cylinder bores formed around an axis of rotation slides with respect to a valve disc, which has a high-pressure port and a low-pressure port and controls the reversal of a piston in each of the cylinder bores as a function of the inclination of a swashplate. Furthermore, the opening shapes of the high-pressure port and the low-pressure port extend circumferentially on the same arc centered around the axis of rotation and are annular band shapes that have no top dead center and no bottom dead center. An opening shape of a cylinder port in each of the cylinder bores, extending circumferentially on the same arc where the high-pressure port and the low-pressure port are located, is an annular band shape that does not communicate with the high-pressure port and the low-pressure port, at least when positioned at top dead center and bottom dead center, and based on the direction of rotation of the cylinder block: opening shapes of the end parts on the front and rear in the direction of rotation of the cylinder port are circular convex shapes; an opening shape of an end part on the front in the direction of rotation of the high-pressure port is a circular concave shape; opening shapes of the end parts on the front and rear in the direction of rotation of the low-pressure port are circular concave shapes;The opening shape of the end part on the front side in the direction of rotation of the cylinder opening and the opening shape of the end part on the back side in the direction of rotation of the low-pressure port are the same; and the opening shape of the end part on the back side in the direction of rotation of the cylinder opening, the opening shape of the end part on the front side in the direction of rotation of the low-pressure port, and the opening shape of the end part on the front side in the direction of rotation of the high-pressure port are the same. Advantageous effects of the invention

[0020] According to the present invention, based on the direction of rotation of a cylinder block, an opening shape of an end part (which can also be called an end region) on the front side in the direction of rotation of a cylinder opening and an opening shape of an end part on the rear side in the direction of rotation of a low-pressure port partially have the same shape, and / or an opening shape of an end part on the rear side in the direction of rotation of the cylinder opening and an opening shape of an end part on the front side in the direction of rotation of the low-pressure port partially have the same shape. As a result, the opening region of the low-pressure port is enlarged, and thus the reduction in suction power can be suppressed, while the rotational support power is increased due to residual pressure inside a cylinder bore during the transition from a discharge process to a suction process. Brief description of the drawings

[0021] Fig. Figure 1 is a sectional view and illustrates a schematic configuration of a hydraulic pump according to an embodiment of the present invention.

[0022] Fig. 2 is a cross-sectional view with respect to line AA of the hydraulic pump, which is located in Fig. 1 is explained.

[0023] Fig. 3 is a view and illustrates a cross-section with respect to line BB of the hydraulic pump, which is located in Fig. 1 is explained, and a cross-section of a working oil accumulator connected to the hydraulic pump.

[0024] Fig. Figure 4 is a view and illustrates a configuration of a sliding surface of a cylinder block with respect to a valve head, viewed in the X direction.

[0025] Fig. 5 is a view and explains opening shapes of a valve head intake port and a valve head discharge port of the valve head with respect to a cylinder port, which is in Fig. 3 is explained.

[0026] Fig. Figure 6 is a view and illustrates opening shapes of a valve disc intake opening and a valve disc discharge opening of a valve disc with respect to a cylinder opening, according to a first modification of the embodiment in the present invention.

[0027] Fig. Figure 7 is a view and illustrates opening shapes of a valve disc intake opening and a valve disc discharge opening of a valve disc with respect to a cylinder opening according to a second modification of the embodiment in the present invention.

[0028] Fig. Figure 8 is a view and illustrates opening shapes of a valve disc intake opening and a valve disc discharge opening of a valve disc with respect to a cylinder opening according to a third modification of the embodiment in the present invention.

[0029] Fig. Figure 9 is a view and illustrates opening shapes of a valve disc intake opening and a valve disc discharge opening of a valve disc with respect to a cylinder opening according to a fourth modification of the embodiment in the present invention.

[0030] Fig. Figure 10 is a view and illustrates an example of an opening shape of a valve disc intake opening with respect to a cylinder opening according to a fifth modification of the embodiment in the present invention.

[0031] Fig. Figure 11 is a view and illustrates an example of an opening shape of the valve plate intake opening with respect to the cylinder opening according to the fifth modification of the embodiment in the present invention. Description of embodiments

[0032] In the following, a hydraulic pump / motor, which is an embodiment of the present invention, is described with reference to the drawings. <Erste Ausführungsform> [Complete configuration of the hydraulic pump]

[0033] Fig. Figure 1 is a sectional view and illustrates a schematic configuration of a hydraulic pump according to a first embodiment of the present invention. Fig. Figure 2 is a line-AA cross-sectional view of the hydraulic pump located in Fig. 1 is explained. The hydraulic pump, which is in Fig. 1 and Fig. As explained in section 2, the motor speed is transferred to a shaft. 1The hydraulic pump converts transmitted torque into hydraulic pressure and then discharges oil drawn in through an intake port P1 through a discharge port P2 as high-pressure working oil. Furthermore, the hydraulic pump is a variable displacement hydraulic pump that adjusts the amount of working oil delivered by changing the tilt angle of a swashplate. 3 may vary.

[0034] In the following, an axis along an axis C of the shaft will be described. 1 referred to as the X-axis, an axis along an inclined central axis, which is a line that defines the pivot points for the swashplate. 3 To tilt, a line connecting the two sides is called the Z-axis, and an axis perpendicular to the X-axis and Z-axis is called the Y-axis. Additionally, the direction is determined by an end piece on one side of the shaft. 1 to an end part of the opposite side, referred to as the X-direction.

[0035] The hydraulic pump points the shaft 1, a cylinder block 6 and the swashplate 3 up. The wave 1 is through a housing 2 and a finishing cap 8 each via stock 9a , 9b The cylinder block is mounted on a rotatable and swiveling bearing. 6 is with the wave 1 via a wedge structure 11 connected, and becomes integral to the rotation with the shaft 1 inside the housing 2 and the end cap 8 driven. The swashplate 3 is between a side wall of the housing 2 and the cylinder block 6 provided for. The cylinder block 6 is equipped with a variety of piston cylinders (cylinder bores) 25 ) provided, which are at equal intervals relating to the circumference (circumferentially) around the axis C of the shaft 1 and parallel to the axis C of the shaft 1 are arranged. A piston 5, which is able to align itself parallel to the axis C of the shaft 1 Moving back and forth is possible in each of the multitude of cylinder bores. 25 introduced.

[0036] The piston 5 , which comes from each of the cylinder bores 25 The protruding part has a spherical-concave shape at its tip. A spherical-convex part of a shoe 4 It fits into the spherical-concave part, and the piston 5 and the shoe 4 They form a spherical shaft bearing. The spherical concave part of the piston 5 It is sealed, thus preventing separation from the shoe. 4 prevented.

[0037] The swashplate 3 has a flat sliding surface S on the cylinder block 6 the side facing the shoe. 4 slides according to the rotation of the shaft 1 geared rotation of the cylinder block 6circular or elliptical as it is pressed against the sliding surface S. A spring 15 , a movable ring 16 , a needle 17 , and a ring-shaped pressure element 18 are around the axis of the shaft 1 provided. The spring 15 is through a ring 14 supported on the inner circumference on the side of the X-direction of the cylinder block 6 is intended. The movable ring 16 and the needle 17 are caused by the spring 15 pressed down. The pressure element 18 bumps against the needle 17 on. The shoe 4 is caused by the pressure element 18 pressed against the sliding surface S.

[0038] On the side wall of the case 2 are two hemispherical shaft bearings 20 , 21 , each on the side of the swashplate 3 protrude upwards, in symmetrical positions with respect to the axis center of the shaft1 Provided. On the side of the housing's side wall. 2 the swashplate 3 There are two concave balls on each part corresponding to the positions where the shaft bearings are located. 20 , 21 were arranged, formed. A swashplate shaft bearing 3 is formed when the shaft bearing 20 , 21 and two concave spheres of the swashplate 3 collide. The shaft bearings 20 , 21 are arranged in the Z-axis direction.

[0039] As in Fig. 2 explained, the swashplate tilts 3 in a plane perpendicular to an XY plane using a line that defines the shaft bearing 20 , 21 connects, as an axis (parallel to the Z-axis). The inclination of the swashplate 3 is by a piston 10 determined, which is during the pressing from one end of the swashplate 3along the X-direction from the side of the case's side wall 2 moved back and forth. The swashplate 3 tilts due to the back-and-forth movement of the piston 10 using the line that the shaft bearing 20 , 21 connects, as a joint line. The sliding surface S also tilts due to the tilt of the swashplate. 3 and thus the cylinder block rotates 6 according to the rotation of the wave 1 For example, it glides, as in Fig. 1 and Fig. 2 explained, in a case where the angle of inclination from an XZ plane is a, when the cylinder block rotates counterclockwise, viewed in the X direction, the shoe 4 circular or elliptical along the sliding surface S, and the piston moves accordingly. 5 inside each of the cylinder bores 25 back and forth.

[0040] If the piston 5to the side of the swashplate 3 When moved, the oil is drawn from an intake opening P1 into each of the cylinder bores. 25 via a valve plate 7 (or valve plate) is drawn in. When the piston 5 to the side of the valve plate 7 When moved, the oil inside each of the cylinder bores is circulated. 25 over the valve plate 7 High-pressure working oil is discharged from discharge port P2. The amount of working oil discharged from discharge port P2 is controlled by adjusting the tilt of the swashplate. 3 Variable control. [Configuration of valve head and cylinder block]

[0041] The one on the side of the end cap 8 fixed valve plates 7 and the cylinder block 6m The rotating parts are in mutual contact via a sliding surface Sa. Fig. 3 is a cross-sectional view with respect to the BB lines of the hydraulic pump, which is in Fig. 1 is explained. Fig. Figure 4 is a view and illustrates a configuration of the sliding surface Sa of the cylinder block. 6 regarding the valve plate 7 , viewed in the X-direction. An end face on the side of the sliding surface Sa of the valve disc. 7 and an end surface on the side of the sliding surface Sa of the cylinder block 6 , who in Fig. 3 and Fig. As explained in section 4, they slide due to the rotation of the cylinder block. 6 one on top of the other.

[0042] As in Fig. 3 explained, the valve plate 7The device features a valve plate intake port PB1, which communicates with the intake port P1, and a valve plate discharge port PB2, which communicates with the discharge port P2. The opening shapes of the valve plate intake port PB1 and the valve plate discharge port PB2 extend circumferentially along the same arc centered on the axis of rotation C and are annular band shapes without a top dead center or a bottom dead center.

[0043] exhibit dead center. As in Fig. As explained in section 4, the openings of the nine cylinder bores are 25 (cylinder openings) 25P ), where the piston 5 moved back and forth, on the side of the sliding surface Sa of the cylinder block 6 The valve plate intake port PB1 and the valve plate discharge port PB2 are located at equal intervals and on the same arc. One opening shape of the cylinder port. 25PWith regard to its circumference, it extends over the same arc where the valve plate intake port PB1 and the valve plate discharge port PB2 are located, and is an annular band shape which, when positioned at top dead center and bottom dead center, does not communicate with the valve plate intake port PB1 and the valve plate discharge port PB2.

[0044] In Fig. 3 and Fig. 4, if the cylinder block 6 rotated clockwise, viewed in a direction towards the X-direction, as in Fig. 3. The discharge process is carried out on the side of the valve disc discharge port PB2, which is located on the upper side of the drawing, and the intake process is carried out on the side of the valve disc intake port PB1, which is located on the lower side of the drawing. Therefore, in such a case, the right end of the drawing is shown in Fig. 3 to top dead center, where the discharge process has switched to the intake process and where the piston 5 maximum towards the side of the sliding surface Sa inside the cylinder bore 25 has moved inwards. The high-pressure status inside the cylinder bore. 25 shifts to a low-pressure state. On the other hand, the left end of the drawing is in Fig. 3 to bottom dead center, where the intake process has switched to the discharge process and where the piston 5 furthest from the side of the sliding surface Sa inside the cylinder bore 25 moved away. If the cylinder opening 25P As the engine passes through bottom dead center, the low-pressure status shifts to a high-pressure status.

[0045] As in Fig. As explained in point 3, there is a notch. 26 in the valve plate 7 provided. The notch 26is designed so that it extends from the end part of the valve disc discharge opening PB2 on the bottom dead center side to the side of the bottom dead center. The notch 26 It has a function of regulating the internal pressure of the cylinder bore. 25 , before the cylinder bore 25 communicates with the valve plate discharge opening PB2. By providing the notch 26 The pressure comes from inside the cylinder bore. 25 gradually approaching the pressure inside the valve disc discharge opening PB2, just immediately before the cylinder bore 25 It communicates with the valve plate discharge port PB2. As a result, erosion and noise from the cylinder bore occur. 25 , which are caused when the cylinder bore 25 Communication with the valve plate discharge opening PB2 is suppressed.

[0046] As in Fig. 3 explained, is in valve plate 7 a residual pressure relief opening30 provided. The residual pressure relief opening 30 is in an area within a rotational movement range E of the cylinder opening 25P and located near top dead center up to the valve disc intake port PB1. The residual pressure relief port 30 is provided in a position that is able to align with the cylinder bore 25 to communicate before the cylinder bore 25 communicates with the valve plate intake port PB1. The residual pressure relief port. 30 is connected via a flow path L1 to a working oil reservoir T. The working oil reservoir T is connected via a flow path L to the valve disc intake port PB1.

[0047] The working oil reservoir T is equipped with a separating plate 50 The system is designed to separate the working oil into zones E1 and E2 in the horizontal direction. The working oil is located inside the cylinder bore. 25The working oil, which contains a large amount of air, flows through flow path L1 into area E1. The working oil is guided from area E2 through flow path L to the valve plate intake port PB1. The air in the working oil that flowed into area E1 is removed in area E1. The clean working oil, with the reduced air content from area E1, flows over the upper part of the baffle plate. 50 into area E2. There is a shielding plate in area E2. 51 , which extends horizontally, is provided at the upper part of an outlet opening for the working oil. By providing the shielding plate 51 The pure working oil, which contains no settled dust or the like, is supplied to the side of the valve plate intake opening PB1.

[0048] From a position where the cylinder opening 25P is located at top dead center, i.e., a position where the circumferential tip end of the cylinder opening is 25Pin the direction of rotation at an angle θ0, up to a position where the cylinder bore 25 with the residual pressure relief opening 30 (Rotational support area Δθ1) communicates, the rotation of the cylinder block is 6 through the pressurized working oil inside the cylinder bore 25 The working oil is typically assisted in the intake port P1 by means of an impeller (not explained) that increases the rotational force of the shaft. 1 The impeller is used; however, depending on the device type, there is a case where the impeller does not need to be used when implementing rotational support. Therefore, by implementing rotational support as much as possible, the energy efficiency can be improved while simplifying the structure.

[0049] Then it flows until the circumferential tip end of the cylinder opening. 25Ppasses through an angle θ1 and the cylinder bore 25 with the residual pressure relief opening 30 communicated, and the cylinder bore 25 communicates with the valve plate intake port PB1 when the circumferential tip end of the cylinder opening 25P at an angle θ2 (residual pressure relief area Δθ2), the pressurized working oil is located inside the cylinder bore 25 via the residual pressure relief opening 30 and the flow path L1 into the working oil reservoir T. As a result, a residual pressure is present inside the cylinder bore. 25 away. [Cylinder opening shapes and valve plate intake opening]

[0050] As in Fig. As explained in section 5, an opening shape PB1b of an end part has an arc on the rear side in the direction of rotation of a conventional valve disc intake port PB1, which projects towards the rear end. Similarly, an opening shape S1a of an end part has an arc on the front side in the direction of rotation of the cylinder opening. 25P an arc that protrudes towards the tip end. Therefore, if the cylinder opening 25P The valve plate intake opening PB1 communicates at an angle θ2, they contact each other at one point, and the communicating area was gradually increased according to the rotation of the cylinder block. 6 enlarged.

[0051] In the present embodiment, the opening shape PB1b of the end part on the rear side in the direction of rotation of the valve plate intake opening PB1 is an opening shape B1b of an end part on the rear side in the

[0052] Direction of rotation thereof. Furthermore, the opening shape B1b of the end part on the back and the opening shape S1a of the end part on the front have the same shape in the direction of rotation. That is, if the cylinder opening 25P with the valve plate intake opening PB1 according to the rotation of the cylinder block 6 communicated, the opening shape S1a of the end part overlaps on the front side in the direction of rotation of the cylinder opening. 25P and the opening shape B1b of the end part on the back in the direction of rotation of the valve disc intake opening PB1. As a result, compared to before, the suction power during the intake process can be increased by the area of ​​the regions E10, E11 illustrated by diagonal lines. That is, it is possible to suppress the reduction in suction power even if the rotation support area Δθ1 is set larger than before.

[0053] If the cylinder opening 25P Communicating with the valve plate intake opening PB1, the opening shape B1b of the end part on the back can be in the direction of rotation of the valve plate intake opening PB1 and the opening shape S1a of the end part on the front can be in the direction of rotation of the cylinder opening. 25P They partially have the same shape and partially overlap.

[0054] Both end parts are chamfered in the radial direction by means of shaft milling, specifically the opening shape B1b of the end part on the back in the direction of rotation of the valve plate intake opening PB1. (First modification)

[0055] In the embodiment described above, the opening shape B1b of the end part on the rear side faces in the direction of rotation of the valve disc intake opening PB1, and the opening shape S1a of the end part on the front side faces in the direction of rotation of the cylinder opening. 25Pthe same form. As in Fig. As explained in section 6, in a first modification, an opening shape B1a of an end part on the front in the direction of rotation of a valve disc intake opening PB1 and an opening shape H1a of an end part on the front in the direction of rotation of a valve disc discharge opening PB2 each have the same shape as an opening shape S1b of an end part on the back in the direction of rotation of a cylinder opening. 25P That is, if the communication between the cylinder opening 25P and the valve plate intake port PB1 according to the rotation of the cylinder block 6 is interrupted, and if the communication between the cylinder opening 25P and the valve plate discharge opening PB2 is interrupted, the opening shape S1b of the end part overlaps on the back in the direction of rotation of the cylinder opening. 25Pwith an opening shape B1b of an end part on the front in the direction of rotation of the valve disc intake opening PB1 and an opening shape H1a of an end part on the front in the direction of rotation of the valve disc discharge opening PB2. As a result, the intake area and the discharge area can be larger than before.

[0056] If the communication between the cylinder opening 25PIf the valve plate intake port PB1 is interrupted, the opening shape B1a of the end part on the front side in the direction of rotation, the opening shape H1a of the end part on the front side in the direction of rotation, and the opening shape S1b of the end part on the rear side in the direction of rotation may be partially identical, and opening shapes B1a and H1a may each partially overlap with opening shape S1b. Opening shape B1a of the end part on the front side in the direction of rotation, or opening shape H1a of the end part on the front side in the direction of rotation, may be identical or partially identical to opening shape S1b of the end part on the rear side in the direction of rotation.

[0057] As in Fig. As explained in section 6, to increase the intake area and the discharge area as described above, it is preferred that the opening areas of the valve plate intake port PB1 and the valve plate discharge port PB2 are widened as much as possible, so that the cylinder opening 25P Communication with the valve plate intake port PB1 and the valve plate discharge port PB2 is only not possible if the cylinder opening 25P is positioned at top dead center and bottom dead center. However, a circumferential rear end-opening position of the valve head intake port PB1, which has a rotation support area Δθ1 where a discharge process transitions into an intake process, is not limited to this. In a case where a notch 26 The cylinder opening is provided on the valve plate discharge opening PB2. 25P only then not with the tip end part of the notch 26 , when the cylinder opening 25Pis positioned at bottom dead center. The opening areas of the valve head intake port PB1 and the valve head discharge port PB2 are widened as much as possible, so that the cylinder opening 25P Communication with the valve plate intake port PB1 and the valve plate discharge port PB2 is only not possible if the cylinder opening 25P is positioned at the top dead center and the bottom dead center; however, in view of manufacturing defects, it is preferred to position the openings PB1 and PB2 separately by a predetermined distance. (Second modification)

[0058] According to a second modification, as in Fig. As explained in section 7, the convex opening shape S1a of the end part on the front side is in the direction of rotation of the cylinder opening. 25PThe opening shape S2a of an end part on the front side is changed in the direction of rotation, and the concave opening shape B1b of the end part on the rear side in the direction of rotation of the valve head intake port PB1 is changed into a convex opening shape B2b of an end part on the rear side in the direction of rotation of a valve head intake port PB1; therefore, the opening shape S2a of the end part on the front side in the direction of rotation and the opening shape B2b of the end part on the rear side in the direction of rotation have the same shape. That is, if a cylinder opening 25P with the valve plate intake opening PB1 according to the rotation of a cylinder block 6 communicated, the opening shape S2a of the end part overlaps on the front side in the direction of rotation of the cylinder opening. 25Pand the opening shape B2b of the end part on the rear in the direction of rotation of the valve head intake opening PB1. Similar to the first modification, overlap when the communication between the cylinder opening 25P and the valve plate intake port PB1 is interrupted, and if the communication between the cylinder opening 25P and the valve plate discharge opening PB2 is interrupted, an opening shape S1b of an end part on the back in the direction of rotation of the cylinder opening 25P with an opening shape B1a of an end part on the front in the direction of rotation of the valve disc intake opening PB1 and an opening shape H1a of an end part on the front in the direction of rotation of the valve disc discharge opening PB2. In this case, the opening shape S2a of the end part on the front in the direction of rotation and the opening shape B2b of the end part on the back in the direction of rotation may also be partially the same. (Third modification)

[0059] According to a third modification, as in Fig. As explained in section 8, this is an opening shape of an end part on the front side in the direction of rotation of a cylinder opening. 25P a convex opening shape S1a of the end part on the front side in the direction of rotation, and an opening shape of an end part on the back side in the direction of rotation of the cylinder opening 25PThe opening shape S2b of the end part on the rear side in the direction of rotation is concave. Accordingly, the opening shape of an end part on the rear side in the direction of rotation of a valve disc intake port PB1 is a concave opening shape B1b of the end part on the rear side in the direction of rotation; the opening shape of an end part on the front side in the direction of rotation of the valve disc intake port PB1 is a convex opening shape B2a of the end part on the front side in the direction of rotation; and the opening shape of an end part on the front side in the direction of rotation of a valve disc discharge port PB2 is a convex opening shape H2a of the end part on the front side in the direction of rotation. Furthermore, the opening shape S1a of the end part on the front side in the direction of rotation and the opening shape B1b of the end part on the rear side in the direction of rotation have the same shape.The opening shape S2b of the end part on the back in the direction of rotation and the opening shape B2a of the end part on the front in the direction of rotation have the same shape. The opening shape S2b of the end part on the back in the direction of rotation and the opening shape H2a of the end part on the front in the direction of rotation have the same shape. That is, if the cylinder opening... 25P communicates with the valve plate intake port PB1, and if the communication between them is interrupted, and if the communication between the cylinder opening 25P If the valve disc discharge opening PB2 is interrupted, one opening shape of the end part overlaps the other in the opening. In this case, the opening shapes may not be completely identical, but they may be partially identical. (Fourth modification)

[0060] According to a fourth modification, as in Fig. As explained in section 9, an opening shape of an end part on the front in the direction of rotation of a cylinder opening is required. 25P and an opening shape of an end part on the back in the direction of rotation of the cylinder opening 25PA concave opening shape S2a of the end part on the front side in the direction of rotation, and a concave opening shape S2b of the end part on the back side in the direction of rotation. Accordingly, an opening shape B2b of an end part on the back side in the direction of rotation of a valve disc intake port PB1 has a convex shape, an opening shape B2a of an end part on the front side in the direction of rotation of the valve disc intake port PB1 has a convex shape, and an opening shape H2a of an end part on the front side in the direction of rotation of a valve disc discharge port PB2 has a convex shape. Furthermore, the opening shape S2a of the end part on the front side in the direction of rotation and the opening shape B2b of the end part on the back side in the direction of rotation have the same shape.The opening shape S2b of the end part on the back in the direction of rotation and the opening shape B2a of the end part on the front in the direction of rotation have the same shape. The opening shape S2b of the end part on the back in the direction of rotation and the opening shape H2a of the end part on the front in the direction of rotation have the same shape. That is, if the cylinder opening... 25P communicates with the valve plate intake port PB1, and if the communication between them is interrupted, and if the communication between the cylinder opening 25P If the valve disc discharge opening PB2 is interrupted, one opening shape of the end part overlaps the other in the opening. In this case, too, the opening shapes do not need to be completely identical, but can partially overlap. (Fifth modification)

[0061] In the embodiment and the first to fourth modifications described above, the opening shapes of the end parts on the front and / or back side in the direction of rotation were circular convex shapes or circular concave shapes; however, the opening shapes of the end parts are not limited to these and can be any shape. For example, any opening shape can be the same as a straight line shape as an opening shape S3a of an end part on the front side in the direction of rotation of a cylindrical opening. 25P and an opening shape B3b of an end part on the rear side in the direction of rotation of a valve disc intake opening PB1, which is in Fig. As explained in section 10, each opening shape can have the same shape with a wave shape with a convex / concave shape as an opening shape S4a of an end part on the front side in the direction of rotation of the cylinder opening. 25Pand an opening shape B4b of an end part on the rear side in the direction of rotation of the valve disc intake opening PB1, which is in Fig. As explained in section 11, the forms may exhibit the same shape. In these cases, the shapes may not be completely identical, but may partially be identical.

[0062] The convex or concave shape of the opening shape in the embodiment and the first to fourth modifications described above has the shape of an inverted U or a U-shape.

[0063] The components of the embodiment and the first to fifth modifications described above can be combined as required.

[0064] In the embodiment and the first to fifth modifications described above, the hydraulic pump was described as an example; however, the invention is not limited to this and can also be applied to a hydraulic motor. In the case of the hydraulic motor, a high-pressure side corresponds to a discharge side of the hydraulic pump, and a low-pressure side corresponds to a suction side of the hydraulic pump.

[0065] In this case too, the rotation of a cylinder block overlaps. 6 , if a cylinder opening 25P communicates with a low-pressure connection, or if the communication between them is interrupted, or if the communication between the cylinder opening 25P and a high-pressure connection is interrupted, any opening shape of the end part in the direction of rotation in the opening completely or partially.

[0066] Furthermore, in the embodiment and the first to fifth modifications, the swashplate hydraulic pump / motor was described as an example; however, the invention is not limited to this and can also be applied to an inclined hydraulic shaft pump / motor. Reference symbol list 1 wave 2 cases 3 Swashplate 4 shoes 5, 10 pistons 6-cylinder block 7 valve plates 8 End cap 9a, 9b Camp 11 Wedge structure 14 rings 15 springs 16 Movable ring 17 needles 18 Pressure element 20, 21 shaft bearings 25 cylinder bore 25P cylinder opening 26 notch 30 residual pressure relief opening 50 separating plate 51 Shielding plate L, L1 Flow path P1 Intake opening P2 Drop-off opening PB1 Valve plate intake opening PB2 valve disc discharge opening S, Sa sliding surface S1a, S2a, S3a, S4a Opening shapes of the end part on the back in the direction of rotation of the cylinder opening S1b, S2b Opening shapes of the end part on the back in the direction of rotation of the cylinder opening B1a, B2a Opening shapes of the end part on the front in the direction of rotation of the valve plate intake opening B1b, B2b, B3b, B4b Opening shapes of the end part on the front in the direction of rotation of the valve plate intake opening H1a, H2a Opening shapes of the end part on the front in the direction of rotation of the valve disc discharge opening T Working oil container

Claims

[1] Hydraulic axial pump / motor, wherein a cylinder block with a plurality of cylinder bores formed about an axis of rotation slides with respect to a valve disc which has a high-pressure port and a low-pressure port and controls the reversal of a piston in each of the cylinder bores depending on the inclination of a swashplate, wherein the opening shapes of the high-pressure port and the low-pressure port extend circumferentially on the same arc centered around the axis of rotation and are annular band shapes that have no top dead center and bottom dead center, an opening shape of a cylinder opening extending in each of the cylinder bores on the same arc with respect to the circumference where the high-pressure port and the low-pressure port are located, and is an annular band shape that does not communicate with the high-pressure port and the low-pressure port, at least when positioned at top dead center and bottom dead center, and based on the direction of rotation of the cylinder block: an opening shape of an end part on the front in the direction of rotation of the cylinder opening and an opening shape of an end part on the back in the direction of rotation of the low-pressure connection partially have the same shape; and / or The opening shape of an end part on the back in the direction of rotation of the cylinder opening and the opening shape of an end part on the front in the direction of rotation of the low-pressure connection may partially have the same shape. [2] Hydraulic pump / motor according to claim 1, wherein the opening shape of the end part on the front side in the direction of rotation of the cylinder opening and the opening shape of the end part on the rear side in the direction of rotation of the low-pressure port have the same shape, and / or the opening shape of the end part on the rear side in the direction of rotation of the cylinder opening and the opening shape of the end part on the front side in the direction of rotation of the low-pressure port have the same shape. [3] Hydraulic pump / motor according to claim 1 or 2, wherein the opening shape of the end part on the front in the direction of rotation of the cylinder opening and an opening shape of an end part on the rear in the direction of rotation of the high-pressure port have partially the same shape, and / or the opening shape of the end part on the rear in the direction of rotation of the cylinder opening and an opening shape of an end part on the front in the direction of rotation of the high-pressure port have partially the same shape. [4] Hydraulic pump / motor according to claim 3, wherein the opening shape of the end part on the front side in the direction of rotation of the cylinder opening and the opening shape of the end part on the rear side in the direction of rotation of the high-pressure port have the same shape, and / or the opening shape of the end part on the rear side in the direction of rotation of the cylinder opening and the opening shape of the end part on the front side in the direction of rotation of the high-pressure port have the same shape. [5] Hydraulic pump / motor according to any one of claims 1 to 4, comprising a residual pressure relief port provided on the valve disc and communicating with the cylinder bore on the top dead center side before the cylinder bore on the top dead center side communicates with the low-pressure port, wherein an opening portion of the end part on the rear side is separated from the top dead center in the rotational direction of the low-pressure port, so that it communicates with an opening portion of the end part on the front side in the rotational direction of the cylinder opening, after the opening portion of the end part on the front side passes through a rotational support area in the rotational direction of the cylinder opening, where the rotation of the cylinder block is supported by pressurized oil inside the cylinder bore from a top dead center position of the cylinder opening, and a residual pressure relief area where the pressure inside the cylinder bore,through communication between the residual pressure relief opening and the cylinder bore, the pressure decreases and transitions into a suction process. [6] Hydraulic pump / motor according to one of claims 1 to 5, wherein at least one of an opening part of the end part on the front in the direction of rotation of the low-pressure port, an opening part of the end part on the rear in the direction of rotation of the high-pressure port, and an opening part of the end part on the front in the direction of rotation of the high-pressure port is formed at a position which only does not communicate with the cylinder opening when the cylinder opening is positioned at top dead center or bottom dead center. [7] Hydraulic pump / motor according to one of claims 1 to 6, wherein the opening shape of the cylinder opening is a cocoon-like annular band shape in which the end parts on the front and the back form arcs in the direction of rotation. [8] Hydraulic pump / motor according to any one of claims 1 to 6, wherein the opening shapes of the high pressure port and the low pressure port are cocoon-like annular band shapes, wherein the end parts on the front and the back form arcs in the directions of rotation. [9] Hydraulic axial pump / motor, wherein a cylinder block with a plurality of cylinder bores formed about an axis of rotation slides with respect to a valve disc which has a high-pressure port and a low-pressure port and controls the reversal of a piston in each of the cylinder bores depending on the inclination of a swashplate, wherein the opening shapes of the high-pressure port and the low-pressure port extend circumferentially on the same arc centered around the axis of rotation and are annular band shapes that have no top dead center and bottom dead center, an opening shape of a cylinder opening in each of the cylinder bores extending circumferentially on the same arc where the high-pressure port and the low-pressure port are located, and is an annular band shape that does not communicate with the high-pressure port and the low-pressure port, at least when positioned at top dead center and bottom dead center, and based on the direction of rotation of the cylinder block: The opening shapes of the end parts on the front and back are circular convex shapes in the direction of rotation of the cylinder opening; The opening shapes of the end parts on the front and back in the direction of rotation of the high-pressure connection and an opening shape of an end part on the front in the direction of rotation of the low-pressure connection are circular convex shapes; an opening shape of an end part on the back in the direction of rotation of the low-pressure connection is a circular concave shape; and The opening shape of the end part on the front side in the direction of rotation of the cylinder opening and the opening shape of the end part on the back side in the direction of rotation of the low-pressure connection have the same shape. [10] Axial-type hydraulic pump / motor, wherein a cylinder block with a plurality of cylinder bores formed about an axis of rotation slides with respect to a valve disc having a high-pressure port and a low-pressure port, and controls the reversal of a piston in each of the cylinder bores depending on the inclination of a swashplate, wherein the opening shapes of the high-pressure port and the low-pressure port extend circumferentially on the same arc centered around the axis of rotation and are annular band shapes that do not include a top dead center and bottom dead center, an opening shape of a cylinder opening in each of the cylinder bores extending circumferentially on the same arc where the high-pressure port and the low-pressure port are located, and is an annular band shape that does not communicate with the high-pressure port and the low-pressure port, at least when positioned at top dead center and bottom dead center, and based on the direction of rotation of the cylinder block: The opening shapes of the end parts on the front and back are circular convex shapes in the direction of rotation of the cylinder opening; an opening shape of an end part on the front in the direction of rotation of the high-pressure connection is a circular concave shape; The opening shapes of the end parts on the front and back in the direction of rotation of the low-pressure connection are circular concave shapes; the opening shape of the end part on the front side in the direction of rotation of the cylinder opening and the opening shape of the end part on the back side in the direction of rotation of the low-pressure connection have the same shape; and The opening shape of the end part on the back in the direction of rotation of the cylinder opening, the opening shape of the end part on the front in the direction of rotation of the low-pressure port, and the opening shape of the end part on the front in the direction of rotation of the high-pressure port have the same shape.

Images