JPH01208577A - Swash plate type piston pump - Google Patents

Abstract

PURPOSE:To prevent abnormal abrasion or seizure by using a static pressure bearing for at least one bearing out of a bearing for supporting a swash plate on an inner rotary body and a bearing for supporting an outer rotary body which supports the inner rotary body on a casing. CONSTITUTION:A cylinder block 1 is provided inside a casing 4 and pistons 12 are provided inside the cylinder block 1. On the other hand, an inner rotary body 10 is rotatably supported by an outer rotary body 8' and these are provided inside a casing 5. A rotary shaft 8 integrally formed with the outer rotary body 8' is supported by the casing 5 via a bearing 9. Further, a swash plate 6 is rotatably provided in the inner rotary body 10 via a bearing 17. Balance pistons 11 are fitted in the inside of the outer rotary body 8'. In this structure, a static pressure bearing is used for at least one of the bearings 9, 17.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotating swash plate type piston pump, and more particularly to a rotating swash plate type piston pump using a highly water-containing working fluid or a high pressure fluid as a working medium.

[Conventional technology]

FIG. 5 shows a conventional rotating swash plate type axial piston pump. Conventionally, as described in, for example, Kansai Shipbuilding Association Magazine, No. 190 (September 1982), the rotating shaft 8 and the swash plate 6 were mounted on rollers and υ bearings 18. 19. It is supported at 20°21. In this case, since it is used underwater as a seawater pump,
The rotating shaft 8. Swash plate 6. The rolling bearings 18, 19, 20.21 are lubricated with oil and separated from the cylinder portion 1 in a sealed structure surrounded by a casing 5 and a seal 21.22. However, the sealing properties of the movable parts are generally not guaranteed over a long period of time, and leakage occurs from the sealing parts. If water were to enter from the outside through the seals 21, 22', complete oil lubrication would eventually become impossible and the life of the roller bearing would be shortened. Conventionally, rolling bearings have been used to support the rotating shaft and swash plate of rotating swash plate type axial piston pumps, and in environments where the roller bearings are exposed to water, oil lubrication is performed using seal f. However, the seal itself was not very reliable, and therefore the life of the roller bearing was also unreliable.

[Problem to be solved by the invention]

In a rotating swash plate type axial piston pump, the thrust component and radial component of the piston reaction force are generated by rollers supported by υ bearings. However, roller υ bearings have a problem in that they have a limited lifespan due to fatigue failure due to repeated stress. Particularly in bearings for pumps with high water content, the low viscosity causes insufficient oil film formation, causing abnormal wear and seizure. In addition, there was a problem in that metal embrittlement and corrosion were accelerated and fatigue strength was significantly reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide a rotary swash plate type piston pump supported by a hydrostatic bearing, which does not have a life limit due to fatigue failure as a support structure for a rotating body.

[Means to solve the problem]

The first object is achieved by providing an oil groove in the casing to form a hydrostatic bearing, or by installing a hydrostatic bearing within the casing.

Furthermore, the second purpose is to install a valve body consisting of a plurality of large-diameter pistons and a plurality of small-diameter pistons in a rotary joint inserted into the rotary shaft in order to apply pressure to the piston chamber of the external rotary body, and a valve body, respectively. This is achieved by providing a freely movable low pressure cylinder section and high pressure cylinder section.

[Effect]

The rotating body support structure using hydrostatic bearings prevents abnormal bearing wear by forming an oil film to prevent contact between the hydrostatic bearing and the rotating body, even in bonders that handle high water content hydraulic fluids or low viscosity fluids. .

No problems such as burn-in occur.

In this case, the pump discharge pressure is applied to the small diameter piston of the valve body of the rotary joint, and the pressure corresponding to the upper limit setting value is applied to the large diameter piston, and the valve body is moved in the axial direction by the large acting force / J't of both. By moving the swash plate to either the left or right side and switching the flow path in the valve of the low-pressure cylinder section, the pressure in the piston chamber of the external rotating body can be controlled to push or pull the tilt control piston and change the tilt angle of the swash plate. can.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

The casing 2 is formed by integrating three divided bodies 3, 4.5. The cylinder block 1, located inside the housing 4, is secured by the housing 3.4. The internal rotating body 10 located inside the casing 5 has its trunnion shaft (not shown) (located perpendicular to the plane of the drawing) supported by an external rotating body 8'. 9 and 17 are hydrostatic bearings; 8 is a rotary shaft supported by a hydrostatic bearing 9 on the casing 5 and integrated with an external rotating body 8'; 6 is rotatable by a static pressure bearing 17 on an internal rotating body 10. 11 is a balance piston inserted into the external rotating body 8', and the balance piston 11 has an inclined surface corresponding to the tilt angle of the swash plate 6 that regulates the reciprocating movement of the piston 12. to the swash plate 6. 12 is a piston fitted into the cylinder block 1 so as to be movable in the axial direction; 13 is a spherical joint provided at the tip of the piston 12; and 14 is a piston shoe.

In the above configuration, the axial piston pump 1
6 rotates the rotating shaft 8 with an appropriate power to suck in low-pressure fluid, and as the rotating shaft 80 rotates, the internal rotary body 10 also rotates, and each piston 12 reciprocates due to the inclination of the swash plate 6. The supplied low pressure fluid is discharged from outlet 1
5 as a high-pressure fluid to perform a pumping action.

During its operation, the bearing supports 9, 17 constantly support fluctuating loads. However, when a highly water-containing working fluid is used as a working medium, it has a low viscosity, so when a rolling bearing is used, the lubricity is extremely poor and problems such as abnormal wear or seizure are likely to occur, leading to fatigue failure. In contrast, in the present invention, since the rotary shaft bearing support part is of a hydrostatic pressure bearing support type, an oil film can always be formed between the hydrostatic pressure bearing 9.17 and the external rotary body 8' and the swash plate 6. Therefore, it can be used semi-permanently.

Further, other embodiments are shown in FIGS. 3 and 4. In this embodiment, the casing 5 has the function of the hydrostatic bearing 9.

Further, a hydrostatic bearing can support any large load by changing the diameter of the hydrostatic pad and the supply pressure. In addition, in the case of rolling bearings, low-temperature lubricity and high abrasion become a problem when highly water-containing hydraulic fluid enters the casing, but according to the present invention, it floats on the sliding surface of the bearing without surface contact. Since it supports the load, there is no need to worry about wear.

Next, another embodiment of the present invention will be described with reference to FIG.

An internal rotating body 104 located at the center of the casing 103 has its trunnion shaft (not shown) (located in a direction perpendicular to the plane of the paper) supported by an external rotating body 105 .

105 is a rotating shaft supported by bearings 6 and 7 in the casing 103 and integrated with the external rotating body 105; 108 is a swash plate rotatably inserted into the internal rotating body 104 via bearings 109;

Reference numeral 110 denotes a tilt control piston inserted into the external rotating body 105, and the tilt control piston 110 has an inclined surface on the swash plate 108 corresponding to the tilt angle of the swash plate 108 that regulates the reciprocating movement of the piston 102. give.

101 is located on the right side of the casing 103, and the piston 1
The cylinder block 111 is a spherical joint provided at the tip of the piston 102, and is a 112Fi piston shoe. 113 is pressure source 1
a suction valve for passing the fluid sent from 15; 114;
116 is a discharge valve through which fluid pressurized by the piston 102 passes, and 116 is a load.

117 is a rotary joint fitted into the rotating shaft 105, and 119 is a large diameter piston 7119a, 119b.

A valve body consisting of 119c and a small diameter piston 119d, 120
121 is a high-pressure cylinder portion into which a small diameter piston 119d is movably fitted, and 121 is a large diameter piston 119a.

Reference numerals 119b and 119c are low-pressure cylinder parts into which the cylinders are movably inserted, 122 is a low-pressure boat to which low-pressure fluid is supplied, and 123 is a tank boat for returning the fluid to the tank. 125 is a piston chamber into which the tilting control piston 110 is fitted, and 124 is a flow path connecting the rotary joint 117 and the piston chamber 125i.

In the above configuration, the rotary swash plate type piston pump 1
26 rotates the rotating shaft 105 with an appropriate power, the rotation of the rotating shaft 105 also rotates the internal rotating body 104, the piston 102 reciprocates by the inclination of the swash plate 108, and the low pressure supplied from the suction valve 113 is Fluid is discharge valve 1
14 as a high-pressure fluid to perform a pumping action.

During the operation, the valve body 119 is pressed to the right by the spring 127, and the switching port 128 is opened to the tank 123 side, and the valve body 119 is pushed to the right by the spring 127, and the switching port 128 is opened to the tank 123 side.
The pressure is close to zero, and the tilt control piston 110 is pushed to the left. As a result, the internal rotating body 104 rotates while being inclined, and the swash plate 108 also rotates while being inclined. Thereby, the piston 102 sucks and discharges fluid. However, when the discharge pressure exceeds the upper limit '5c, the discharge pressure is guided to the high pressure cylinder section 120, thereby pushing the valve body 119 to the left. Then, since the switching port 128i1 is connected to the low pressure boat 122, low pressure acts on the piston chamber 125 via the flow path 124, and the tilting control piston 110
is pushed to the right, and the internal rotary body 104 gradually makes its slope gentler until it reaches zero. Accordingly, the slope of the swash plate 108 becomes zero, and the repump no longer discharges.

As described above, according to the present invention, the discharge flow rate becomes zero when the upper limit set value of the pump discharge pressure is exceeded, so that the burden on the pipes and equipment on the pump discharge side can be reduced. Moreover, if the discharge pressure falls below the upper limit set value, discharge can be started automatically.

〔Effect of the invention〕

According to the present invention, wear and seizure of the bearing can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG.
3 is a sectional view showing another embodiment,
FIG. 4 is a sectional view taken along the line ■-■ in FIG. 3, FIG. 5 is a diagram showing a conventional example, and FIG. 6 is a diagram showing another embodiment of the present invention. 8... Rotating shaft, 9... Static pressure bearing, lO... Internal rotating body, 8'... External rotating body. Agent Patent Attorney Katsuo Ogawa゛・- Fig. 1←Work No. 20 Kaya 3 Fig.←Work□ Kaya 4 (2) 乎 5-dent P&I 21

Claims (1)

[Scope of Claims] 1. A cylinder block fixed to a casing, a plurality of pistons fitted into the cylinder block so as to be movable in the axial direction, and a head of the pistons that is movable in the axial direction. A swash plate to support, a bearing to support the swash plate, an internal rotating body to hold the swash plate via a bearing, an external rotating body to rotatably support the internal rotating body, and the external rotating body. A rotating swash plate type piston pump consisting of a bearing supported on a casing and a rotating shaft integrally formed on the other end side of the external rotating body, wherein at least one of the bearings is a hydrostatic bearing. A rotating swash plate type piston pump featuring: 2. A cylinder block fixed to the casing, a plurality of pistons fitted into the cylinder block so as to be movable in the axial direction, and a swash plate that slidably supports the head of the piston; an internal rotary body that holds the swash plate; an external rotary body that supports the internal rotary body in a tiltable manner; and a tilt control piston that is fitted into a piston chamber of the external rotary body and tilts the internal rotary body. and a rotating swash plate type piston pump comprising a rotating shaft integrally formed on the other end side of the external rotating body, and a rotary joint rotatably fitted into the rotating shaft, the rotary joint having a plurality of rotary joints. A rotary swash plate type piston pump characterized in that the valve body includes a large-diameter piston and a small-diameter piston, and a low-pressure cylinder portion and a high-pressure cylinder portion, each of which is movable.