KR20050028831A - Axial piston fluid pump motor - Google Patents

Abstract

A fluid pump motor in the shape of axial piston is provided to decrease a flow rate of fluid toward fluid ports and reduce noise caused by collision between fluid, thereby restraining the fluid noise even though pressure of the fluid is increased. A fluid pump motor in the shape of axial piston includes a slide contact surface(50) of a slide contacting a cylinder block of a timing plate(42). The contact surface is formed with cutaway grooves(51,52,57,58) extended between fluid ports(43,44) from high pressure side to low pressure side. The cutaway grooves respectively have a sectional surface, of which a depth becomes smaller toward the fluid ports of low pressure. The sectional surface is in the shape of rectangular groove approximately. Both side surfaces(53,54) of the groove are inclined to become wider toward the slide contact surface.

Description

Axial piston fluid pump motor

The present invention relates to an axial piston fluid pump and motor with an improved timing plate.

As a conventional axial piston fluid pump motor, what is described in Unexamined-Japanese-Patent No. 2000-97146 (following patent document 1) is known, for example.

It includes a case, a cylinder block housed in the case and rotatable about an axis, a plurality of flangers slidably inserted into a cylinder chamber formed in the cylinder block and protruding or drawing in and out of the fluid into the cylinder chamber, and the case and the cylinder block. A timing plate having a bow-shaped pair of fluid ports mounted on the case and installed in the casing and performing flow in and out of the cylinder chamber, the slide contact surface being in sliding contact with the cylinder block of the timing plate; The cutting groove extending toward the low pressure side fluid port is formed at the rear end in the rotational direction of the side fluid port.

The patent document 1 describes a cutting groove that gradually decreases as the width and depth approaches the low pressure side fluid port, and gradually increases as the V notch having a V-shaped cross section or the depth approaches the low pressure side fluid port. At the same time, a point notch in which the cross section is substantially rectangular is used.

Herein, in order to improve the performance of the axial piston type fluid pump and motor (hereinafter, referred to as a fluid motor) as described above, the fluid motor is rotated at high speed by increasing the pressure of the fluid supplied to the fluid motor. There is a problem that a large noise occurs when the fluid motor rotates at high speed.

The reason for this is that, firstly, when the supply pressure of the fluid is increased as described above, the velocity of the fluid ejected into the cylinder chamber through the notch is also increased, so that the ejected fluid (hereinafter referred to as "classification") becomes the cylinder chamber (Kidney port). This is because the impact sound when it collides with the inner surface becomes large. Secondly, when the fluid is ejected into the cylinder chamber (kidney port) as described above, the fluid (fluid in the Kidney port) around this jet is drawn into the jet. In this case, the pressure around the jet decreases, and as the jet velocity increases, the pressure drop also increases, causing cavitation to occur severely in a wider range, and as a result, the impact sound when the bubbles generated by the cavitation bursts. I think.

An object of the present invention is to provide an axial piston type fluid pump and motor which is simple in structure and can effectively suppress noise during high speed rotation by reducing collisions in a cylinder chamber of a jet or pressure drop around the jet. do.

This object includes a case, a cylinder block housed in the case and rotatable about an axis, a plurality of flangers slidably inserted into a cylinder chamber formed in the cylinder block and protruding or drawing in and out of the fluid into the cylinder chamber, and the case. And a timing plate having a bow-shaped pair of fluid ports mounted to the case and installed between the cylinder block and performing fluid flow in and out of the cylinder chamber, the slide contact surface being in sliding contact with the cylinder block of the timing plate. An axial piston fluid pump / motor having a cutting groove extending toward the low pressure side fluid port at a rear end of the high pressure side fluid port in a rotational direction, wherein the cross section becomes shallower as the cutting groove is directed toward the low pressure side fluid port. At the same time, the groove is formed into a substantially rectangular groove, and both sides of the groove This can be achieved by inclining to widen toward the slide contact surface. Moreover, the fluid pump motor of this invention is a fluid apparatus which shows a motor action and a pump action by the same structure by the flow path connected.

(Example 1)

EMBODIMENT OF THE INVENTION Hereinafter, Embodiment 1 of this invention is described with reference to drawings.

In Fig. 1, reference numeral 11 denotes an axial piston fluid pump motor, in which an inclined plate type fluid motor, the fluid motor 11 has a case body 12, the other end of which is one end face of the case body 12. The shrinkage chamber 13 of the cross section circular shape which extends toward is formed. In addition, one end of the case main body 12 is fixed to the side plate 14 by a bolt or the like not shown, whereby the opening of the storage chamber 13 is blocked by the side plate 14 and sealed. It becomes a space. The case main body 12 and the side plate 14 mentioned above comprise the case 15 of the fluid motor 11 as a whole.

16 is a rotating shaft in which one side is inserted into the storage chamber 13. The rotating shaft 16 is connected to the case 15 through a pair of bearings 17 and 18, and in detail, the side plate 14 and the case body ( 12) is rotatably supported, respectively. And the other end of this rotating shaft 16 protrudes from the case main body 12, and is connected to the speed reducer which is not shown in figure. 19 is a sealing member provided between the other end part of the rotating shaft 16 and the case main body 12. As shown in FIG.

23 is a cylindrical cylinder block accommodated in the storage chamber 13 of the case 15. In this cylinder block 23, a thrust member 24 having a substantially cylindrical shape is inserted, and the thrust member 24 is provided. And the cylinder block 23 are connected to each other by spline coupling. In addition, the thrust member 24 is fitted to the outside of the rotary shaft 16 and is connected to the rotary shaft 16 by spline coupling. As a result, these rotary shafts 16 and the cylinder block 23 are connected. And the thrust member 24 may be integrally rotated around the axis of the rotation shaft 16.

The cylinder block 23 is provided with a plurality of cylinder chambers 25 extending in parallel to the axis line (nine in the present embodiment), and these cylinder chambers 25 are arranged at equal distances in the circumferential direction. In these cylinder chambers 25, a plurality of flangers 26 (the same number as the cylinder chambers 25) are inserted so as to be slidable, and a spherical ball portion 27 is provided at the front end of each flanger 26, that is, at the other end. Formed. In addition, each cylinder chamber 25 has a bow-shaped Kidney port 28 centered on the axis at one end thereof, and these Kidney ports 28 are open to one end surface of the cylinder block 23. . Although the number of the cylinder chambers 25 and the flanger 26 is not specifically limited, It is preferable to set it as odd, and it can be seven, 11, etc. other than nine.

31 is an inclined plate disposed in the storage chamber 13 between the cylinder block 23 in the case 15 on the other side, in detail, between the other end surface of the cylinder block 23 and the other inner surface of the case 15. The 31 is rotatably connected to the case 15 by a pin or the like not shown, and the rotation shaft 16 penetrates through the inside thereof. The inclined surface 32 opposite to the cylinder block 23 of the inclined plate 31 is inclined with respect to the vertical plane perpendicular to the axis. As a result, the inclined plate 31 has a thick portion 33 and a thin portion at the center thereof. It can be divided into (34). 35 is the same number of shoes as the flanger 26, and each shoe 35 is provided with a ball hole 36 in which approximately half of the ball portion 27 is accommodated.

In addition, the front end (the other end) of each flanger 26 is slidably hung on the inclined surface 32 of the inclined plate 31 via the shoe 35. As a result, when the fluid is supplied (inflowed) to the cylinder chamber 25, the flanger 26 rotates toward the thin portion 34 in the thick portion 33 while gradually protruding from the cylinder chamber 25, When the fluid is discharged (outflowed) from the cylinder chamber 25, the flanger 26 rotates toward the thick portion 33 from the thin portion 34 while gradually drawing into the cylinder chamber 25.

38 is a substantially ring-shaped retainer plate inserted to the outside of the rotation shaft 16 so that the retainer plate 38 is disposed between the cylinder block 23 and the inclined plate 31. The retainer plate 38 is engaged with all the shoes 35, and the radially inner end portion is in spherical contact with the outer circumference of the other end of the thrust member 24. As shown in FIG. 39 is a spring disposed between the thrust member 24 and the snap ring 40 caught on the inner circumference of one end of the cylinder block 23, and the biasing force of the spring 39 is the thrust member 24 and the retainer plate 38. Is transmitted to the shoe 35 through the), and the shoe 35 is pushed onto the inclined surface 32 of the inclined plate 31, and transferred to the cylinder block 23 to describe the cylinder block 23 later. Push it onto the plate.

1, 2, 3, and 4, 42 is provided between the cylinder block 23 and the case 15, specifically, the side plate 14, in surface contact with them, and is better than the cylinder block 23. As a ring-shaped timing plate with a slightly larger diameter, the timing plate 42 is rotatably mounted to the case 15 via a pin or the like. The timing plate 42 is formed with a pair of long bow-shaped fluid ports 43 and 44 about an axis, and the fluid port 43 has a protruding side stroke end and an inlet side stroke of the flanger 26. On one side of the straight line connecting the ends, the fluid port 44 is also arranged on the other side of the straight line, 180 degrees apart from each other in the circumferential direction.

45 and 46 are the inflow and outflow passages formed in the case 15, specifically the side plate 14, the inflow and outflow passage 45 to the fluid port 43, the inflow and outflow passage 46 to the fluid port 44, respectively It is always in communication. These inflow and outflow passages 45 and 46 are connected to a pump and a tank via a switching valve (not shown). When the switching valve is switched, one of them flows into the high pressure (supply) side and the other flows into the low pressure (discharge) side.

When the outflow passage 45 is connected to the pump to the high pressure side and the outflow passage 46 is connected to the tank to the low pressure side, the fluid port 43 on the high pressure side is supplied from the outflow passage 45. The high pressure fluid is guided to the cylinder chamber 25 located on one side of the straight line, while the low pressure fluid discharged from the cylinder chamber 25 located on the other side of the straight line is connected to the low pressure fluid outlet 44. Guide cylinder 46 is made to rotate the cylinder block 23 forward in the direction shown by the arrow in FIG.

On the contrary, when the inflow passage 46 is connected to the pump to the high pressure side and the outflow passage 45 is connected to the tank to the low pressure side, the high pressure side fluid port 44 is supplied from the outflow passage 46. The fluid is guided to the cylinder chamber 25, while the low pressure side fluid port 43 guides the low pressure fluid discharged from the cylinder chamber 25 to the inflow and outflow passage 45 to guide the cylinder block 23 to FIG. The motor is rotated in the reverse direction to the direction indicated by the arrow.

When the high pressure fluid is supplied to the inflow passage 45 as described above, the fluid port 43 becomes the high pressure side fluid port and the cylinder block 23 rotates forward, and the rear end of the fluid port 43 rotates in the rotational direction. In the slide contact surface 50 in sliding contact with the cylinder block 23 of the timing plate 42, a bow-shaped cutting groove 51 extending toward the fluid port 44, which is a low pressure side fluid port, is formed. On the other hand, when the high pressure fluid is supplied to the inflow passage 46 contrary to the above, the fluid port 44 becomes the high pressure side fluid port and the cylinder block 23 reversely rotates, and the fluid port 44 rotates. In the slide contact surface 50 of the timing plate 42 at the rear end in the direction, a bow-shaped cutting groove 52 extending toward the fluid port 43 which is the low pressure side fluid port is formed. Here, the rotation direction described above means the rotation direction of the cylinder block 23.

If the cutting grooves 51 and 52 are provided at such a position, the Kidney port 28 of the cylinder chamber 25 is connected to the fluid port 43 or 44 on the high pressure side by the rotation of the cylinder block 23. The high pressure fluid flows gradually into the cylinder chamber 25 through the cutting grooves 51 or 52 immediately before the high pressure fluid flows into the cylinder chamber 25 from the fluid port 43 or 44 on the high pressure side. Since the inflow is slightly increased while increasing the pressure, the sudden and large pressure change of the high-pressure fluid is alleviated to reduce the noise.

Here, the cutting grooves 51 and 52 are both deeper toward the low pressure side fluid port (the fluid port 44 for the cutting groove 51 and the fluid port 43 for the cutting groove 52). At the same time, the radial cross section is constituted by grooves having a substantially rectangular shape, and both side surfaces 53 and 54 of these grooves are inclined to widen toward the slide contact surface 50 (cylinder block 23). As a result, the radial cross section of the said cutting grooves 51 and 52 has shown the pedestal shape in which the slide contact surface 50 side is a long side, and the bottom surface is a short side. In addition, the cutting grooves 51 and 52 having such a shape can be easily cut into a phrase mill or the like using a cutting tool (for example, an end mill) matching the cross-sectional shape of the cutting grooves 51 and 52. Therefore, the processing cost is not increased.

When the cutting grooves 51 and 52 are configured as described above, the cylinder chamber 25 (kidney port 28) is brought into the cutting grooves 51 or 52 by the rotation of the cylinder block 23. In other words, when approaching the high pressure side fluid port 43 or 44, in other words, when the overlapping amount between the Kidney port 28 and the cutting groove 51 or 52 gradually increases, the cutting groove 51 or The flow path cross-sectional area of the high pressure fluid flowing through 52 is wider than the cutting grooves (V notches, point notches) described in the background art at any circumferential position.

As a result, the velocity of the fluid ejected through the cutting groove 51 or 52 into the cylinder chamber 25 (kidney pot 28) is reduced, thereby reducing the impact sound caused by the collision of the jet and at the same time surrounding the jet. Also, the pressure drop of the cavities decreases, and the impact sound when the bubbles of the cavitation bursts also decreases. In this simple structure, noise can be effectively suppressed even at high fluid pressure for high speed rotation.

In addition, in the first embodiment, the cutting groove extending from the slide contact surface 50 toward the fluid ports 43 and 44 at the high pressure side also at the front end in the rotational direction at the fluid ports 44 and 43 at the low pressure side ( 57 and 58, respectively, and at the same time, the cutting grooves 57 and 58 are also composed of grooves having a substantially rectangular cross section (reverse support shape) whose depth becomes shallower toward the fluid ports 43 and 44 on the low pressure side. At the same time, both side surfaces 53 and 54 of this groove are inclined so as to extend toward the slide contact surface 50.

Thus, when the cutting grooves 57 and 58 are installed in the fluid ports 44 and 43, when the switching valve is switched from the flow position to the neutral position and the fluid motor 11 performs the pumping action, the cylinder chamber 25 The high pressure fluid extruded by the flanger 26 from the low pressure side fluid port 44 through the cutting groove 57 at the forward rotation, and through the cutting groove 58 at the reverse rotation, 43), each of which is jetted, and the sorting speed at this time can be lowered as described above, so that noise can be effectively suppressed. Further, in the above-described embodiment, the cutting grooves 51, 52, 57, 58 are provided because the fluid motor 11 rotates forward and reverse, but the fluid motor 11 rotates in one direction (for example, forward rotation). ), The cutting grooves 52 and 58 may be omitted, or the V notch or pointed notch described in the background art may be used.

Here, when the inclination angle (inclination angle with respect to the straight line perpendicular to the slide contact surface 50) A of both side surfaces 53 and 54 of the groove in the cutting grooves 51, 52, 57, 58 is 30 degrees or more, Noise can be suppressed strongly. However, when the inclination angle A exceeds 50 degrees, the width of the proximal ends of the cutting grooves 51, 52, 57, 58 becomes wider than the width of the fluid ports 43, 44, and the noise suppression effect is saturated. There is. In this regard, the inclination angle A is preferably in the range of 30 to 50 degrees.

Further, the radial direction of the cutting grooves 51, 52, 57, 58 at a position circumferentially away from the distal end of the cutting grooves 51, 52, 57, 58 toward the fluid ports 43, 44 by 10 degrees. When the cross-sectional area is 3 mm 2 or more, the noise can be suppressed more strongly. However, when the said cross-sectional area exceeds 6 mm <2>, the circumferential length of the cutting grooves 51, 52, 57, 58 may become short and the noise suppression effect may be reduced. In this regard, the cross-sectional area is preferably in the range of 3 to 6 mm 2.

In addition, as described above, when the cross-sectional area at a position 10 degrees away from the tip of the cutting grooves 51, 52, 57, 58 is in the range of 3 to 6 mm 2, the cross-sectional area at a position separated by 14 degrees is 5 to 5 degrees. It is preferable to carry out in the range of 9 mm <2>. This is because if it is within this range, the rate of increase of the cross-sectional area in the cutting grooves 51, 52, 57, 58 becomes an appropriate value, and the noise suppression effect is assured.

Next, the operation of the first embodiment will be described.

It is assumed that the switching valve is now switched, and the inflow passage 45 and the fluid port 43 are connected to the pump to the high pressure side, and the outflow passage 46 and the fluid port 44 are connected to the tank to the low pressure side. At this time, the high pressure fluid is supplied (inflowed) from the outflow passage 45 to the cylinder chamber 25 located on one side of the straight line through the fluid port 43, and the flanger 26 in the cylinder chamber 25 is inclined. Protrude toward (31) and pushed to the inclined surface (32). As a result, a force directed to the thinnest portion of the inclined plate 31 acts on these flangers 26, thereby giving the cylinder block 23 a torque around the axis. As a result, the flanger 26, the cylinder block 23, the rotary shaft 16 is integrally rotated in the forward rotation direction, at which time the flanger 26 of the one side together with the shoe 35 on the inclined surface (32) Slide toward the thinnest portion of the inclined plate 31.

By the rotation of the cylinder block 23, the flanger 26 positioned on the other side of the straight line is engaged with the inclined surface 32 of the inclined plate 31 through the shoe 35, and the thickest portion of the inclined plate 31 is formed. As it moves toward the surface, it is pushed into the inclined surface 32 and gradually introduced into the cylinder chamber 25 to extrude the fluid in the cylinder chamber 25 and discharged into the tank through the fluid port 44 and the inflow and outflow passage 46. (Spill) As a result of the rotation of the cylinder block 23 as described above, the connection between the cylinder chamber 25 and the fluid ports 43 and 44 located on one side and the other side of the straight line changes one after another.

Here, when the Kidney port 28 of the cylinder chamber 25 which rotated slightly from the inlet side stroke end toward the thin part 34 side of the inclined plate 31 reaches the cutting groove 51, and they overlap, the cutting groove ( 51, the high pressure fluid is ejected into the cylinder chamber 25 (kidney port 28), and the cross section of which the depth becomes shallow as the cutting groove 51 is directed to the low pressure side fluid port 44 is approximately The fluid ejected into the cylinder chamber 25 (kidney port 28) is formed by the rectangular groove and inclined so that both side surfaces 53 and 54 of the groove widen toward the slide contact surface 50. The speed of the is lowered, whereby the noise is effectively suppressed.

Further, when the switching valve is switched so that the inflow passage 46 is connected to the pump and the outflow passage 45 is connected to the tank, the cylinder in which the high pressure fluid is located on the other side of the straight line from the inflow passage 46 and the fluid port 44 is located. At the same time as being supplied (inflowed) to the chamber 25, the fluid pushed out from the cylinder chamber 25 located on one side of the straight line is discharged (outflowed) from the fluid port 43 and the inflow and outflow passage 45, and the rotating shaft (16), the cylinder block 23 rotates in the reverse direction. In this state, when the Kidney port 28 overlaps the cutting groove 52, the high pressure fluid is ejected to the cylinder chamber 25 (Kidney port 28) through the cutting groove 52. Similarly, the velocity of the fluid jetted into the cylinder chamber 25 (kidney pot 28) is lowered, whereby noise is effectively suppressed.

In addition, when the switching valve is switched from the flow position to the neutral position and the fluid motor 11 performs the pumping action, the high pressure fluid extruded by the flanger 26 from the cylinder chamber 25 is cut in the forward rotation. Through the 57 to the fluid port 44 on the low pressure side, and in the reverse rotation to the fluid port 43 on the low pressure side through the cutting groove 58, respectively, the velocity of the jet at this time as well as described above Since it can reduce, a noise can be suppressed effectively.

(Example 2)

5 is a diagram showing Embodiment 2 of the present invention. In the second embodiment, the groove bottom of each cutting groove 59 is formed with a bow-shaped groove 60 having a rectangular cross section with the same width as the groove bottom. In this way, when the groove 60 of the bow shape is further formed at the bottom of the groove of the cutting groove 59, the cross-sectional area of the flow path can be increased to suppress the noise more effectively.

(Example 3)

Fig. 6 is a diagram showing Embodiment 3 of the present invention. In the third embodiment, the cross section is formed in a bow shape so as to deepen the groove bottom of each cutting groove 61 toward the center in the width direction. This makes it possible to smooth the flow of the fluid and at the same time slightly increase the cross-sectional area of the flow path as compared with the flat groove bottom, so that the noise can be suppressed more effectively.

Next, a test example is demonstrated. In this test, the conventional motor in which the V notches were formed in both the front and rear ends of the high pressure and low pressure side fluid ports, and the cutting described in Example 1 in both the front and rear ends of the high pressure and low pressure side fluid ports were rotated. A well-known sirloin whose grooves are formed in a groove and a high and low pressure side fluid port, both before and after the rotational direction, whose width and depth are constant irrespective of the circumferential position and whose cross section is substantially rectangular. A reference motor with notches was prepared.

And the noise was measured while changing the rotation speed per unit time of each of these motors, and the result is shown in FIG. In Fig. 7, the curve indicated by the dashed-dotted line corresponds to the conventional motor having the V notch, the curve indicated by the solid line corresponds to the published motor having the cutting groove of the present invention, and the curve indicated by the dotted line corresponds to the reference motor having the fillet notch, It can be seen that the noise in the published motor is more effectively suppressed at high speeds than the noise in the conventional motor. Further, in the reference motor, since a certain amount of fluid passes through the fillet notch and is ejected into the cylinder chamber from the initial stage of overlapping the Kidney port and the fillet notch, the pressure change is insufficient, and at any rotational speed, A loud noise is occurring.

In addition, in the above-described embodiment, the case where the fluid pump motor is an inclined plate type fluid motor has been described. However, the present invention may be an inclined shaft type fluid motor. In addition, in the above-described embodiment, the inclination plate type fluid motor has been described, but in the present invention, the inclination plate type or the inclination axis type fluid pump may be used. In this case, when the flanger is drawn into the cylinder chamber, the high pressure fluid is discharged (outflowed) through the high pressure side fluid port, while the low pressure fluid is sucked in (flowed in) through the low pressure side fluid port when the flanger protrudes from the cylinder chamber. do.

Incidentally, in the above-described embodiment, the inclination angles A of both side surfaces 53, 54 of the cutting grooves 51, 52, 57, 58 are the same at any circumferential position, but in the present invention, the circumferential center portion In this case, the inclination angles of these two side surfaces may be changed, for example, the inclination angle of the proximal end side (side close to the fluid port) may be larger than the inclination angle of the front end side. This increases the cross-sectional area of the flow path and improves the noise reduction effect.

In the present invention, the cylinder groove is inclined so that both sides of the groove are widened toward the slide contact surface while the cutting groove is composed of a substantially rectangular groove whose depth becomes shallow as the cutting port is directed toward the low pressure side fluid port. The flow path cross section of the cutting groove when the cutting groove approaches the high pressure side fluid port is wider than the conventional cutting groove (notch) at any position. As a result, the velocity of the fluid jetted through the cutting groove into the cylinder chamber or the fluid port decreases, thereby reducing the impact noise caused by the collision of the jets and at the same time, the pressure drop around the jets. The impact sound is also reduced. In this simple structure, noise can be effectively suppressed even at high fluid pressure for high speed rotation.

In addition, when configured as described in claim 2, the noise when the fluid motor performs the pumping action or when the fluid pump performs the motoring action can be effectively suppressed by the same operation as described above.

Moreover, if comprised as described in Claim 3, a noise can be suppressed strongly.

In addition, when configured as described in claim 4, the noise can be suppressed more strongly.

In addition, if it constitutes as described in Claim 5, the flow path cross-sectional area in a cutting groove will become an appropriate value of increase rate, and the noise suppression effect will be sure.

Further, the present invention can be applied to an axial piston type, that is, a swash plate type and a bent axis fluid pump motor.

1 is a front sectional view showing a first embodiment of the present invention.

2 is a right side view of the timing plate.

3 is a cross-sectional view taken along the line II of FIG. 2.

4 is a cross-sectional view taken along the line II-II of FIG. 3.

Fig. 5 is a sectional view of the same manner as in Fig. 4 showing Embodiment 2 of the present invention.

FIG. 6 is a cross-sectional view in the same manner as in FIG. 4 showing Embodiment 3 of the present invention; FIG.

7 is a graph showing test results.

(Explanation of symbols for the main parts of the drawing)

11 Fluid Pumps & Motors

15 cases

23 cylinder blocks

25 cylinder chamber

26 flanger

42 timing plate

43, 44 fluid ports

50 Slide Contact

51, 52, 57, 58 cutting groove

53, 54 side

A tilt angle

Claims (10)

A cylinder block accommodated in the case and rotatable about an axis, a plurality of flangers slidably inserted into a cylinder chamber formed in the cylinder block and protruding or drawing in and out of the fluid into the cylinder chamber; A timing plate mounted to the case in a state of being installed between the cylinder blocks, wherein a pair of fluid ports for carrying out flow of the fluid into the cylinder chamber are formed in a bow shape, and the cylinder of the timing plate A first cutting groove is formed on the slide contact surface in sliding contact with the block at the rear end of the high pressure side fluid port toward the low pressure side fluid port, and both sides of the cutting groove are inclined to widen toward the slide contact surface. Axial Piston Fluid Pumps motor. The method of claim 1, An axial piston fluid pump and motor, characterized in that the first cutting groove is formed into a substantially rectangular groove whose depth is shallow as it is directed to the low pressure side fluid port. The method of claim 1, On the slide contact surface, a second cutting groove extending toward the high pressure side fluid port is formed at the front end side of the low pressure side fluid port, and both sides of the second cutting groove are inclined to be widened toward the slide contact surface. Axial piston fluid pumps and motors. The method of claim 3, wherein The axial piston fluid pump and motor, characterized in that the second cutting groove comprises a groove that is shallow in depth as it is directed to the high pressure side fluid port. The method of claim 1, An axial piston fluid pump and motor, wherein the inclination angles of both side surfaces of the first cutting groove are in a range of 30 to 50 degrees. The method of claim 1, An axial piston fluid pump and motor, characterized in that the cross-sectional area at a position 10 degrees away from the tip of the first cutting groove to the fluid port is within the range of 3 to 6 mm 2. The method of claim 6, An axial piston fluid pump motor, characterized in that the cross-sectional area at a position separated by 14 degrees from the distal end of the first cutting groove is within a range of 5 to 9 mm 2. The method of claim 3, wherein An axial piston fluid pump and motor, wherein the inclination angles of both side surfaces of the second cutting groove are in a range of 30 to 50 degrees. The method of claim 3, wherein An axial piston fluid pump and motor, wherein the cross-sectional area at a position 10 degrees away from the tip of the second cutting groove to the fluid port side is within the range of 3 to 6 mm 2. The method of claim 9, An axial piston fluid pump motor, characterized in that the cross-sectional area at a position separated by 14 degrees from the tip of said second cutting groove to the fluid port is within the range of 5 to 9 mm 2.