JPH04203279A - Slant plate type hydraulic rotary machine - Google Patents

Abstract

PURPOSE:To prevent a reduction in a mechanical efficiency even if a shoe is finely deformed and to prevent a wear of the shoe or the like by a method wherein the shoe is stored in a shoe storing groove in a shoe supporting plate and the shoe supporting plate is rotatably contacted with a slant plate or the like. CONSTITUTION:As a rotary shaft 3 is driven, a cylinder block 9 is integrally rotated and slidably rotated in respect to a valve plate 4. Each of shoes 23 is held by a shoe pressing plate 17 and rotated together with a cylinder block 9 and a piston 21. In this case, each of the shoes 23 is stored in a shoe storing groove 26 of a shoe supporting plate 25, the shoe supporting plate 25 is integrally rotated with the shoes 23, i.e., the cylinder block 9 and a piston 21. Accordingly, the shoe supporting plate 25 is slidably rotated at its slant plate contacting surface on a sliding plane 31 of the shoe supporting plate of the slant plate 30. As a result, since the sliding amount of each of the shoes 23 is low, it is possible to prevent phenomenon of reducing a mechanical efficiency, occurrence of wear, biting and seizure or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a swash plate type hydraulic rotating machine used as a variable capacity or fixed capacity swash plate type hydraulic pump, hydraulic motor, or the like.

[Conventional technology]

Conventionally, as a swash plate type hydraulic rotating machine, a swash plate type variable displacement hydraulic pump shown in FIGS. 6 to 11 has been known.

In the figure, 1 is a head casing, 2 is a body casing, and these casings 1 and 2 are connected by a cylindrical casing body (not shown) to constitute the casing. 3 is the helad casing 1. A rotating shaft is rotatably provided between the bottom casings 2, and the rotating shaft 3 is supported by a bearing (not shown). Reference numeral 4 denotes a disc-shaped valve plate, which is fixed to the head casing 1 via a bottle (not shown), and has a pair of semicircular arc-shaped supply/discharge ports 5 and 6. are provided symmetrically on the left and right (see Figure 4). The head casing 1 is provided with liquid passages 7 and 8 that are constantly in communication with the supply/discharge port 5.6.

Reference numeral 9 denotes a cylinder block formed in a cylindrical shape. The cylinder block 9 is located inside the casing and is provided to pass through the rotating shaft 3, and rotates integrally with the rotating shaft 3 via male and female splines 10. The valve plate sliding surface 9A, which is one end surface of the valve plate sliding contact surface 9A, is connected to a pressurized spring 2, which will be described later.
O's spring force and the hydraulic pressure in the cylinder hole 11 cause the cylinder block sliding surface 4A of the valve plate 4 to be in close contact with the cylinder block sliding surface 4A so as to be able to slide and rotate. The cylinder block 9 has a plurality of cylinder holes 11, 11. ... are bored in the axial direction, and one end side of each cylinder hole 11 is an oval cylinder port 1], A that opens to the valve plate sliding surface 9A. Furthermore, double oil grooves 12.1.2, which are a combination of circumferential and radial grooves, are formed on the valve plate sliding surface 9A of the cylinder block 9 (
(see FIG. 8), the oil stored in the oil groove 12 causes the valve plate 4 to
When the cylinder block 9 slides and rotates, a lubricating action is applied to the cylinder block 9.

1.3,13. . . . are pistons provided reciprocally in each cylinder hole 11, and the tip of each piston 13 protrudes from the other end surface 9B of the cylinder block 9 to form a spherical portion 13A. 14, 14, . . . indicate shoes that are swingably connected to the spherical portion 13A of each piston 13 on one end side, and the other end side of each shoe 14 is a flat shoe of a swash plate 15, which will be described later. It is adapted to slide and rotate on the sliding contact surface 15C.

Reference numeral 15 denotes a swash plate consisting of a circular flat plate portion 15A and a pair of tooth portions protruding from the other side of the flat plate portion 15A so as to sandwich the rotating shaft 3; and 5B (however, only one side is shown); The flat plate portion 15A of No. 15 has a flat shoe sliding contact surface 15C on one side.
Then, the shoe 14 slides and rotates, and the pair of teeth 15
The other side surface of B becomes a convex curved sliding surface 15D, and the sliding surface 1
5D is a concave curved sliding surface 1 formed on the bottom casing 2
6 is fitted. The valve plate 15 is configured to slide and tilt on a concave curved sliding surface 16 by a tilting actuator (not shown).

Furthermore, 17 is a ring-shaped shoe press plate, and each shoe 14 is fitted into the shoe press plate 17, respectively.

Reference numeral 18 denotes a shoe presser temporary pressing member which is provided between the other end surface 9B of the cylinder block 9 and the shoe presser plate 17, and whose end surface on the side of the shoe presser plate 17 is a convex curved surface. A rotating shaft 3 passes through the rotating shaft 3 and is connected to the rotating shaft 3 via male and female splines 19 so as to rotate integrally. Reference numeral 20 denotes a pressurizing spring stretched between the cylinder block 9 and the shoe presser temporary pressing member 18, and the spring force of the pressurizing spring 20 causes the pressing member 18 and the shoe presser plate 1 to be pressed.
7 to the shoe sliding contact surface 15c of the valve plate 15.
At the same time, the cylinder block 9 is pressed against the valve plate 4.

The swash plate type hydraulic pump according to the prior art is constructed as described above, and among the pair of supply and discharge ports h5 and 6 provided on the valve plate 4, one supply and discharge port 5 is connected to the suction side bow 1-1, and the other supply and discharge port 5 is connected to the suction side bow 1-1. The operation when the exhaust port 6 is used as a discharge port will be described.

First, when the rotating shaft 3 is rotationally driven using a driving device (not shown) such as an engine, the cylinder block 9 rotates integrally with the rotating shaft 3 and slides and rotates with respect to the valve plate 4.

Each shoe 14 is held by a shoe holding plate 17 and rotates together with the cylinder block 9 and piston 13, and each shoe 14 slides and rotates on the shoe sliding surface 15C of the swash plate 15.

As a result, each piston] 3 reciprocates within the cylinder hole 11, and during the suction stroke in which each piston 13 is pushed from the top dead center to the bottom dead center, the liquid passage 7 passes through the suction bows 1 to 5 into each cylinder hole. Pressure oil is sucked into 11, and during the discharge stroke from bottom dead center to top dead center, the pressure oil sucked into each cylinder hole 1 is discharged from discharge port 1-6 to liquid passage 8 as high pressure oil. . The pumping action is performed in this manner, and by tilting the swash plate 15 using the tilting actuator, the discharge capacity can be made variable.

[Problem to be Solved by the Invention 1] However, in the prior art, while the cylinder block 9 rotates, the piston 13. The shoe 14 also rotates integrally, and the shoe 14 rotates while slidingly contacting the shoe sliding surface 15C of the swash plate 15.

Also, while each piston 13 reciprocates, the piston 13 on the discharge stroke side is caused by pressure oil in the cylinder hole 1].
A pressing force as shown by arrow Fs in FIG. 9 is acting.

Furthermore, a large number of shoes 14 (nine in this embodiment) slide and rotate on a swash plate 15'', and in response to the desire to downsize the structure of the hydraulic rotating machine, the system is designed as shown in FIG. The axial dimension C1 of the shoe 14 and the area A of the sliding surface are limited, and these shapes cannot be made too thick.

Due to the three problems mentioned above, especially when performing a pump action, if the pressing force FS becomes large due to high pressure oil, the shoe 14
The sliding surface side of the shoe is deformed into a curved shape as shown in FIG. 10, and slides and rotates on the swash plate 15 and the shoe sliding surface 15C. Moreover, since the shape of the shoe 14, especially the area A of the sliding surface is limited, the lubrication condition when sliding and rotating on the shoe sliding surface 15C of the swash plate 15 is extremely poor. These disadvantages include a decrease in mechanical efficiency as a hydraulic rotating machine, and occurrence of wear, galling, seizure, etc. of the piston 13 and shoe 14.

Furthermore, when the cylinder block 9 rotates at high speed, a centrifugal force F shown in the direction of the arrow in FIG. There is also a drawback that the shoe 14 slides and rotates in a state where it is in partial contact with the shoe 14, causing uneven wear, galling, etc.

The present invention was developed in view of the problems of the prior art, and aims to prevent phenomena such as wear, galling, and seizure of the shoe by minimizing the amount of sliding displacement of the shoe as much as possible. Another object of the present invention is to provide a swash plate type hydraulic rotating machine that is designed to improve mechanical efficiency.

[Means for Solving the Problems] In order to achieve the above object, the swash plate type hydraulic rotating machine according to the present invention has a configuration including a casing, a rotating shaft rotatably supported by the casing, and a rotating shaft rotatably supported by the casing. a valve plate provided on one side in the axial direction of the casing and having a pair of semicircular arc-shaped supply/discharge ports; a cylinder block that rotatably slides into contact with the valve plate; and a plurality of holes are provided in the axial direction of the cylinder block so as to surround the rotating shaft, and the cylinder block is intermittently connected to the pair of supply/discharge ports while the cylinder block rotates. A cylinder hole having a communicating cylinder port, a plurality of pistons provided in each of the cylinder holes so as to be reciprocally movable, the tip side of which protrudes from the other side of the cylinder block, and a plurality of pistons that are movable on the tip side of each piston, respectively. a plurality of attached shoes; a shoe support plate having one side formed with a plurality of shoe accommodation grooves for respectively accommodating the shoes; and the other side serving as a swash plate sliding contact surface; and the other axial side of the casing. a swash plate that is tilted or tiltable, and one side of which serves as a shoe support plate sliding contact surface that rotatably slides on the swash plate sliding contact surface of the shoe support plate; and the shoe support plate. one or more pressure chambers provided on at least one of the sliding contact surface of the swash plate and the sliding contact surface of the shoe support plate of the swash plate; It consists of a piston, a shoe, and a curved extension provided through the shoe support plate.

Further, the pressure chamber can be formed as a semicircular groove having substantially the same shape as at least the high-pressure side supply/discharge port of a pair of supply/discharge ports provided on the valve.

Further, the pressure chambers can be formed as a plurality of oval grooves having substantially the same shape as cylinder ports of a plurality of cylinder holes opening in one end surface of the cylinder block.

[Function] With this configuration, each shoe is housed in the shoe housing groove provided on one side of the shoe support plate, and the other side of the shoe support plate is in rotatable sliding contact with the swash plate. Therefore, when the piston and shoe rotate together with the cylinder pro-tsuku, the shoe support plate slides and rotates on the sliding contact surface of the shoe support plate of the swash plate, reducing the amount of shoe sliding to virtually zero. It can be done. At this time, there is a gap between the swash plate sliding surface of the shoe support plate and the shoe support plate sliding surface of the swash plate.
Since more than one pressure chamber is provided and pressure oil in the cylinder hole is introduced through the curve, the hydraulic pressure balance between the shoe support plate and the swash plate is maintained, and the shoe support plate rotates smoothly. be able to.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to FIGS. 1 to 5. Note that the same components as those in the prior art described above are given the same reference numerals, and their explanations will be omitted.

1 to 4 show a first embodiment of the invention.

In the figure, 21, 21. , . . . are pistons according to the present embodiment, and each piston 21 is provided reciprocatingly in the cylinder hole 1 like the piston 13 according to the prior art, and has a spherical portion 2LA at the tip. This embodiment differs from the embodiment in that a curved line 21 is bored in the axial direction on the tip side of the piston 21 to communicate the cylinder hole 11 with pressure chambers 27, 32, and 33, which will be described later.

23.23. . . . are shoes according to the present embodiment, and each shoe 23 is also pivotally connected at one end side to the spherical portion 21A of each piston 21 similarly to the shoe 14 according to the prior art. The shoe 23 is different in that the other end side of the shoe 23 is accommodated in a shoe housing groove 26 of a shoe support plate 25 to be described later, and a curved lead 24 communicating with the curved lead 22 is bored in the axial direction.

Next, reference numeral 25 denotes a shoe support plate in the form of an annular plate, which is slidably supported by a swash plate 30, which will be described later, and into which the rotating shaft 3 is loosely fitted, and one side of the shoe support plate 25 is a shoe support surface. 25A, and the other side is a flat swash plate sliding contact surface 25B. Here, each shoe 23 is provided on the shoe support surface 25A side.
Oval or circular shoe housing grooves 26, 26, . Further, the swash plate sliding surface 25B side has an elliptical shape corresponding to each cylinder port 11A so that it has almost the same shape as the valve plate sliding surface 9A of the cylinder block 9 shown in FIG. Pressure chambers 27, 27.・
... are formed, and double oil grooves 28, 28 are formed which are a combination of circumferential and radial grooves, and the shoe support plate 25 has a groove between each shoe housing groove 26 and the pressure chamber 27. 29, 29. ... are bored in the axial direction (see Figure 3).

Furthermore, 30 is a swash plate according to the present embodiment, and the swash plate 30 also has a flat plate portion 30A and a pair of protruding parts on the other side of the flat plate portion 30A so as to sandwich the rotating shaft 3. The other side of each tooth 30B is a convex curved surface 30C, which is rotatably fitted into the concave curved sliding surface 6 formed on the bottom casing 2. However, one side of the swash plate 30 according to the present embodiment becomes a shoe support plate sliding contact surface 31 in the shape of a concave circular groove, and the shoe support plate sliding contact surface 3
1 is different in that pressure chambers 32 and 33 consisting of a pair of semicircular grooves are formed so as to have almost the same shape as the cylinder block sliding surface 4A of the valve plate 4 shown in FIG. . Note that 34 is an annular projection surrounding the outer periphery of the shoe support plate sliding surface 3], and the shoe support plate 25 is positioned in the radial direction by the annular projection 34.

The swash plate type hydraulic pump of this embodiment is constructed as described above, but as in the prior art, a pair of supply/discharge balls 1-
5. Among the 6, connect one of the supply/discharge ports 1-5 to the suction side port,
The operation when the other supply/discharge port 6 is used as a discharge port will be described.

First, when the rotating shaft 3 is rotationally driven using a driving device (not shown) such as an engine, the cylinder block 9 rotates integrally with the rotating shaft 3 and slides and rotates with respect to the valve plate 4.

Each shoe 23 is held by the shoe press plate 17 and rotates together with the cylinder block 9 and the piston 21.

At this time, in this embodiment, each of the shoes 23 is accommodated in the shoe housing groove 26 of the shoe support plate 25, so that the shoe support plate 25 is connected to the shoe 23, that is, the cylinder block 9. It rotates integrally with the piston 21. Therefore, the shoe support plate 25 has its swash plate sliding surface 25B slidingly rotated on the shoe support plate sliding surface 31 of the swash plate 30.

As a result of the shoe 23 being guided to the swash plate 30 via the shoe support plate 25, each piston 21 reciprocates within the cylinder hole 11, and each piston 21 reciprocates from top dead center to bottom dead center. In the suction stroke, pressurized oil is sucked into each cylinder hole 1 from the liquid passage 7 through the suction port 5, and in the discharge stroke, which moves back from the bottom dead center to the top dead center, the pressure oil sucked into each cylinder hole 11 is is discharged as high-pressure oil from the discharge port 6 to the liquid passage 8. In this way, a pumping action is performed.

However, in this embodiment, each shoe 23 is accommodated in each shoe housing groove 26 of a shoe support plate 25, and the shoe support plate 25 slides on the swash plate 30, and each shoe 23 itself is Even if there is a slight deformation within each shoe housing groove 26, the amount of sliding is minute. For this reason, the piston 21
Pressing forces F and I as shown in FIG. 9 are applied to the shoe 2.
3 causes minute deformation as shown in FIG. 10, since the amount of sliding of each shoe 23 itself is minute, it may cause a decrease in mechanical efficiency as in the prior art, or cause wear, galling, seizure, etc. It is possible to prevent the occurrence of this phenomenon.

Further, the pressing force FS acting on each piston 21 is the same as that of the shoe 23. It is received by the shoe support plate sliding surface 31 of the swash plate 30 via the shoe support plate 25 . Therefore, the pressure-receiving area of the entire pressing force acting on the piston 21 on the high-pressure side is the entire area of the shoe support plate sliding contact surface 31, making it possible to secure a sufficient pressure-receiving area and significantly reducing the surface pressure. be able to.

Furthermore, in this embodiment, the swash plate sliding contact surface 2 of the shoe support plate 25
Cylinder port 1 of each cylinder hole 11 on the 5B side. I
Pressure chambers 27, 27°, . The piston 2 is formed in these pressure chambers 27, 32, 33.
1. The shoe 23° and the oil passage 22° drilled in the shoe support plate 25 respectively are configured to communicate with the cylinder hole 11 through the 6 24.29, and the high pressure oil in the cylinder hole 11 is transferred to the pressure chamber 27.32.
33. For this reason, the shoe support plate 2
The high-pressure oil introduced as described above generates a separating force between the swash plate sliding surface 25B of No. 5 and the shoe support plate sliding surface 31 of the swash plate 30 to maintain a good hydraulic balance and lubricate. The sliding contact surfaces 25B can be slid and rotated in the state of
.

This prevents galling and seizure phenomena caused by increased surface pressure between 31 and 31. Furthermore, the swash plate sliding surface 25B of the shoe support plate 25 has almost the same shape as the valve plate sliding surface 9A of the cylinder block 9, and the shoe support plate sliding surface 31 of the swash plate 3o also has the same shape as the valve plate sliding surface 9A of the cylinder block 9.
Although it has almost the same shape as the cylinder block sliding surface 4A of can be equal to the cylinder block 9,
The sliding rotation of the shoe support plate 25 can be made extremely good.

Furthermore, since each shoe 23 is accommodated in the shoe accommodation groove 26 of the shoe support plate 25, even if a centrifugal force F as shown in FIG. Since it is reliably supported within the groove 26, it does not cause uneven contact, galling, etc. as in the prior art.

Next, FIG. 5 shows a swash plate according to a second embodiment of the present invention, and the same components as those of the swash plate according to the first embodiment are marked with a dash ('), and their explanation will be omitted. do.

However, in the swash plate 30' according to this embodiment, the semicircular arc-shaped pressure chamber 33' is formed only on one side of the shoe support plate sliding surface 31', which is the high pressure side.

Although the present embodiment is configured as described above, when the cylinder block 9 rotates to perform a pump action, the pressing force F3 is applied only to the piston 21 on the discharge stroke side. Pressing force FI+ by piston 21
is Shoe 23. Via the shoe support plate 25, it acts on only one side of the shoe support plate sliding contact surface 31 that is on the high pressure side. Therefore, a configuration in which only the pressure chamber 33' is provided as in the present embodiment can achieve the same effect as in the first embodiment, but it is particularly suitable for a single-rotation hydraulic pump whose rotation direction is determined. suitable.

In addition, in the embodiment, the swash plate sliding contact surface 25B of the shoe support plate 25
cylinder port 1. Although the configuration is such that the same number of pressure chambers 27 as LA and double oil grooves 28, 28 are formed, these pressure chambers 27. It is also possible to eliminate the oil groove 28 and make it flat, and to open only the armholes 29, 29°, . . . . In this case, the pressure chamber 32 shown in FIG.
．． 33 or only the pressure chamber 33' shown in FIG. 5 is provided.

Further, in the first embodiment, a pair of pressure chambers 32.33 are formed on the shoe support plate sliding surface 31 of the swash plate 30, but these pressure chambers 32.33 are eliminated, and FIG. A plurality of pressure chambers 27, 27, . . . and a double oil groove 28 shown in FIG.
．． 28 may be formed on the shoe support plate sliding surface 31. In this case, the swash plate sliding contact surface 25B side of the shoe support plate 25 becomes a flat surface, and the armholes 29, 29. ...
It is sufficient to adopt a configuration in which only the opening is open.

Furthermore, in the first embodiment, the pair of pressure chambers 32 and 33 provided on the shoe support plate sliding surface 31 of the swash plate 30 are eliminated, and the shoe support plate sliding surface 31 is formed into a flat surface, and one Pressure chamber 27 on the swash plate sliding contact surface 25B side of the shoe support plate 25,
27. . . may be omitted, and the pressure chamber may be formed as a pair of semicircular grooves as shown in FIG.

Furthermore, the swash plate type hydraulic rotating machine according to the present invention is not limited to a hydraulic pump, and may of course be used as a hydraulic motor, and the swash plate 30 is a fixed capacity type with a constant tilting angle. Of course, a swash plate type hydraulic rotating machine may also be used.

[Effects of the Invention] The swash plate type hydraulic rotating machine according to the present invention is as described above in detail, and the shoe is accommodated in the shoe housing groove provided in the shoe support plate, and the shoe support plate is rotated by the swash plate. one or more pressure chambers are provided on at least one of the swash plate sliding contact surface of the shoe support plate and the shoe support plate sliding surface of the swash plate, and pressurized oil in the cylinder hole is provided. Since the curved line leading to the pressure chamber is provided through the piston, shoe, and shoe support plate, even if a large pressing force is applied to the piston due to the pressure inside the cylinder and the shoe is slightly deformed, the mechanical Reduced efficiency, shoe wear, galling, seizure,
This prevents phenomena such as uneven contact, and since the pressure-receiving area between the shoe support plate and the swash plate is large, the surface pressure between them can be significantly reduced. Since the pressure oil in the cylinder hole is guided through the curved line, it improves the pressure balance and lubrication between the shoe support plate and the swash plate, improving mechanical efficiency and preventing seizure. It has the effect of being able to do things.

[Brief explanation of the drawing]

1 to 4 relate to a first embodiment of the present invention, FIG. 1 is a longitudinal sectional view of a swash plate type hydraulic rotating machine according to this embodiment, and FIG. 2 is a side view of the shoe support plate of the shoe support plate. 3 is a plan view showing the swash plate sliding contact surface of the shoe support plate, FIG. 4 is a plan view showing the shoe support plate sliding surface of the swash plate, and FIG. 5 is a plan view showing the sliding contact surface of the shoe support plate of the swash plate. The plan view showing the sliding contact surface of the shoe support plate of the swash plate according to the embodiment, FIGS. 6 to 11, relate to the prior art,
Fig. 6 is a longitudinal sectional view showing a conventional swash plate type hydraulic rotating machine, Fig. 7 is a plan view showing the sliding contact surface of the cylinder block on the valve plate, and Fig. 8 shows the sliding contact surface of the cylinder block on the valve plate. A plan view, FIG. 9 is an external view showing the piston and shoe combination, FIG. 10 is an external view similar to FIG. 9 showing the shoe in a deformed state, and FIG. 11 is a state in which centrifugal force is applied to the shoe. FIG. 9 is an external view similar to FIG. DESCRIPTION OF SYMBOLS 1... Head casing, 2... Bottom casing, 3... Rotating shaft, 4... Valve plate, 4A... Cylinder block sliding surface, 5.6... Supply/discharge port, 9... ...Cylinder block, 9A...Valve plate sliding surface, 11...Cylinder hole, ], LA...Cylinder port, 21...
Bis I・N, 21A... Spherical part, 22, 24.29・
... Curved progression, 23... Shoe, 25... Shoe support plate, 25A... Shoe support surface, 25B... Swash plate sliding contact surface, 26... Shoe accommodation groove, 27.32, 33 .33'
...Pressure chamber, 30.30'...Swash plate, 31.31'
... Shoe support plate sliding contact surface.

Claims (3)

[Claims] (1) a casing, a rotating shaft rotatably supported by the casing, a valve plate provided on one axial side of the casing and having a pair of semi-circular supply and discharge ports; a cylinder block that is positioned so as to rotate integrally with the rotating shaft, and one side of which rotatably slides in contact with the valve plate; , a cylinder hole having a cylinder port that communicates intermittently with the pair of supply/discharge ports while the cylinder block rotates, and a cylinder hole provided in each cylinder hole so as to be reciprocally movable, the tip side facing away from the other side of the cylinder block. A plurality of protruding pistons, a plurality of shoes each swingably attached to the tip side of each piston, a plurality of shoe accommodation grooves for accommodating each shoe respectively are formed on one side, and the other side is slanted. A shoe support plate serving as a plate sliding contact surface is provided in a tilted or tiltable manner toward the other side in the axial direction of the casing, and one side of the shoe support plate rotatably slides into contact with the swash plate sliding contact surface of the shoe support plate. A swash plate serving as a sliding contact surface of the shoe support plate, and one or more pressure chambers provided on at least one of the swash plate sliding contact surface of the shoe support plate and the shoe support plate sliding contact surface of the swash plate. and an oil passage provided through the piston, the shoe, and the shoe support plate for guiding the pressure oil in the cylinder hole to the pressure chamber. (2) The pressure chamber is formed as a semicircular groove having substantially the same shape as at least the high-pressure side supply and discharge port of the pair of supply and discharge ports provided on the valve plate. Swash plate type hydraulic rotating machine. (3) Claim (1) wherein the pressure chamber is formed as a plurality of oval grooves having substantially the same shape as cylinder ports of a plurality of cylinder holes opening in one end surface of the cylinder block.
The swash plate type hydraulic rotating machine described in .