JP3562857B2 - Axial piston pump / motor - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to an improvement of an axial piston pump motor.
[0002]
[Prior art]
To improve the suction and discharge characteristics of an axial piston pump / motor, there is one disclosed in Japanese Utility Model Laid-Open Publication No. 63-96372.
[0003]
As shown in FIGS. 8 to 10, a cylinder block 2 that rotates integrally with the drive shaft 8 is provided inside the casing 1, and the cylinder block 2 is arranged at equal intervals on the same circumference around the drive shaft 8. A plurality of cylinders 3 are formed, and a piston 4 is slidably inserted into each cylinder 3. The tips of the pistons 4 come into contact with the swash plate 5.
[0004]
The bottom surface of the cylinder block 2 comes into contact with a valve plate 6 fixed to a port block 7, and the valve plate 6 has a discharge side high pressure port 10 and a suction side low pressure port 11, each of which is formed in an arc shape. 2, and sequentially communicates with a communication hole 9 that communicates with the cylinder 3 formed therein.
[0005]
When the cylinder block 2 rotates together with the drive shaft 8, the piston 4 reciprocates in the cylinder 3 while sliding on the swash plate 5, and in the suction stroke in which the piston 4 comes out, the valve plate 6 is connected to the suction hole of the port block 7. The fluid is sucked into the cylinder 3 from the low-pressure port 11, and the fluid in the cylinder 3 is discharged from the high-pressure port 10 to the discharge hole in a compression stroke in which the piston 4 is pushed.
[0006]
In such an axial piston pump, the pressure change of the fluid flowing into the cylinder 3 and the fluid discharged from the cylinder 3 is moderated as much as possible to reduce the pump noise. , And similarly, a notch groove 13 is formed from the start end of the low-pressure port 11 toward the high-pressure port 10.
[0007]
[Problems to be solved by the invention]
However, in this case, as the cylinder block 2 rotates, the communication hole 9 of the cylinder 3 cuts off the communication with the high-pressure port 10, and at the moment when the communication hole 9 communicates with the cutout groove 13 of the low-pressure port 11, the high-pressure fluid remaining in the cylinder 3 becomes low-pressure. At the moment when the communication hole 9 of the cylinder 3 cuts off the communication with the low pressure port 11 and communicates with the notch groove 12 of the high pressure port 10, the high pressure fluid is jetted from the high pressure port 11 into the low pressure cylinder 3. I do.
[0008]
As is apparent from FIG. 10, the shape of the notch grooves 12 and 13 is formed in a triangular pyramid shape having a substantially isosceles triangular cross section, so that at the moment of the communication, the high-pressure jet with cavitation is generated. It collides with the side surface of the low-pressure port 11 or the inner wall of the cylinder 3 to generate noise or cause erosion.
[0009]
An object of the present invention is to solve the above-described problem by reducing the number of Reynolds nozzles in a cross section of a notch groove and suppressing a jet accompanied by cavitation.
[0010]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided an axial piston pump / motor having a substantially triangular pyramid-shaped notch formed at an end of a high-pressure port or a low-pressure port of a valve plate that is in sliding contact with a cylinder block. A large number of grooves extending in the direction of ejection.
[0011]
In a second aspect based on the first aspect, the groove width of each of the grooves is reduced so as to intersect at the apex of the triangular pyramid.
[0012]
In a third aspect based on the first aspect, the groove width of each of the grooves is formed in the same width and in parallel with each other.
[0013]
In a fourth aspect based on the first aspect, the groove width of each groove increases toward the apex of the triangular pyramid.
[0014]
[Action]
In the first invention, since a large number of grooves are provided at the bottom of the left and right grooves of the notch groove, the cross-sectional shape of the notch groove is substantially the same as the opening area, and the wet edge length is increased. The number drops. For this reason, turbulence of the high-pressure jet flowing through the notch groove can be suppressed, cavitation can be reduced, and generation of noise and erosion can be suppressed.
[0015]
In the second to fourth inventions as well, similarly, the cavitation of the jet can be suppressed by increasing the wet edge length without changing the opening area of the notch groove.
[0016]
【Example】
FIG. 1 shows a first embodiment in which the present invention is applied to an axial piston pump, in which a notch groove 12 provided at a start end of a high pressure port 10 formed in a valve plate 6 and a start end of a low pressure port 11 are provided. The cutout groove 13 provided has a generally isosceles triangular cross section as a whole, and is formed in a triangular pyramid shape extending tangentially from the port end with respect to each port circumferential center line. And 14b, a number of grooves 15 are formed in the direction of the jet.
[0017]
In this embodiment, each groove 15 has a semicircular cross-section, and all the grooves intersect at one point at the apex of the triangular pyramid. It is formed so that the width increases.
[0018]
Since a large number of grooves 15 are formed on the left and right groove bottoms 14a and 14b of the notch grooves 12 and 13 as described above, for example, the communication hole 9 of each cylinder 3 When the communication is cut off and the low-pressure port 11 communicates with the low-pressure port 11 through the notch groove 13, when the high pressure in the cylinder 3 blows out toward the low-pressure port 11, the opening area of the notch groove 13 is almost the same as the conventional one. By increasing the length of the wet edge, the number of Reynolds nozzles in the high-pressure jet can be reduced, so that the turbulence of the flow is reduced and the jet accompanied by cavitation is suppressed.
[0019]
As a result, erosion due to the jet colliding with the side surface of the low-pressure port 11 is reduced, and noise is reduced.
[0020]
This means that when the communication hole 9 of the cylinder 3 cuts off the communication with the low-pressure port 11 and communicates with the high-pressure port 10, even when high pressure from the high-pressure port 10 blows into the cylinder 3, a large number of grooves are formed. By the notch groove 12 having 15, cavitation of the high-pressure jet can be suppressed, and erosion and noise can be reduced.
[0021]
Next, a second embodiment shown in FIG. 2 will be described. In this embodiment, a large number of grooves 16 formed on the left and right groove bottoms 14a and 14b of the notch grooves 12 and 13 have the apex of the triangular pyramid as described above. , And have the same groove width extending parallel to each other.
[0022]
Also in this case, similarly to the above-described embodiment, the length of the wet edge can be increased to reduce the number of Reynolds nozzles, and the erosion and noise due to the high-pressure jet can be reduced without substantially changing the opening areas of the notched grooves 12 and 13. .
[0023]
The third embodiment of FIG. 3 will now be described. This is different from the first embodiment in that a large number of grooves 17 are formed such that the groove width increases toward the apex of the triangular pyramid. It is.
[0024]
Also in this case, as in the first and second embodiments, the generation of erosion and noise due to the high-pressure jet can be reduced.
[0025]
Each of the groove sections 15 to 17 was semicircular, but as shown in FIGS. 4 to 7, a rectangular section 18a, a slit groove section 18b, a U-shaped section 18c, and a step (triangular) section 18d. The length of the wet edge may be increased. In any case, the groove width can be reduced, enlarged, or formed parallel to the apexes of the notched grooves 12 and 13.
[0026]
The cross section of the notch groove is not limited to a substantially isosceles triangle, but may be an arbitrary triangle.
[0027]
In any of the embodiments, it is possible to effectively reduce erosion and noise generated by the high-pressure jet.
[0028]
Note that, in the above-described embodiment, an application example as an axial piston pump has been described. However, the present invention can be similarly applied to an axial piston motor.
[0029]
【The invention's effect】
According to the first invention, by arranging a large number of grooves on the left and right groove bottoms of the notch groove, the wetted edge length is increased while the opening area of the cross-sectional shape of the notch groove is substantially the same, and the Reynolds nozzle is formed. The number can be reduced, turbulence of the high-pressure jet flowing through the notch groove can be suppressed, cavitation can be suppressed, and erosion and noise can be reduced.
[0030]
In the second to fourth inventions as well, the cavitation of the jet can be suppressed by increasing the length of the wet edge without changing the opening area of the notch groove, as described above.
[Brief description of the drawings]
1A and 1B show a first embodiment of the present invention, wherein FIG. 1A is a plan view, FIG. 1B is a sectional view, and FIG. 1C is a front view.
FIGS. 2A and 2B show a second embodiment, wherein FIG. 2A is a plan view, FIG. 2B is a sectional view, and FIG.
3A and 3B show a third embodiment, wherein FIG. 3A is a plan view, FIG. 3B is a cross-sectional view, and FIG. 3C is a front view.
FIG. 4 is a front view of a notched groove according to a fourth embodiment.
FIG. 5 is a front view of a notched groove according to a fifth embodiment.
FIG. 6 is a front view of a notched groove according to a sixth embodiment.
FIG. 7 is a front view of a notched groove according to a seventh embodiment.
FIG. 8 is a sectional view of a conventional axial piston pump / motor.
FIG. 9 is a plan view of the valve plate.
10A and 10B show a cutout groove, FIG. 10A is a plan view, FIG. 10B is a sectional view, and FIG. 10C is a front view.
[Explanation of symbols]
2 Cylinder block 3 Cylinder 4 Piston 6 Valve plate 9 Communication hole 10 High pressure port 11 Low pressure port 12 Notch groove 13 Notch groove 14a Groove bottom 14b Groove bottom 15 Groove 16 Groove 17 Groove

Claims (4)

In an axial piston pump / motor having a generally triangular pyramid-shaped notch at an end of a high-pressure port or a low-pressure port of a valve plate that is in sliding contact with a cylinder block, a plurality of grooves extending in a fluid jetting direction are formed at the bottom of the left and right grooves of the notch. An axial piston pump / motor characterized by forming a groove. 2. The axial piston pump / motor according to claim 1, wherein the groove width of each of the grooves decreases so as to intersect at the apex of the triangular pyramid. The axial piston pump / motor according to claim 1, wherein the groove widths of the respective grooves are the same and are formed in parallel with each other. 2. The axial piston pump / motor according to claim 1, wherein the groove width of each of the grooves increases toward the apex of the triangular pyramid.

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