JPS6223578A - Axial piston type fluid machine - Google Patents

Abstract

PURPOSE:To enhance the control ability of an axial piston type fluid machine, by acting the pressure of working fluid upon the rear section of a swash plate to cancel out a tilting torque acting upon the swash plate and based upon the pressure of working fluid in a cylinder chamber so that a control torque is reduced. CONSTITUTION:Two fluid actuators 27a, 27b are formed in a front plate 7c in an axial piston type fluid machine. Plungers 28a, 28b in the fluid actuators are made to abut at their ends against the tip dead center side and bottom dead center side a convex spherical surface 5b of the rear section of a swash plate 5, after piercing through a cam holder 23. Further, these fluid actuators 27a, 27b are communicated with the discharge and suction ports 16, 23 of the fluid machine through passages 29a, 29b.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an axial piston type fluid machine used as a pump or a motor.

(Prior Art) An example of a conventional axial piston type pump is shown in FIGS. 6 to 10, in which 1 is a cylinder block, 2 is a pulp plate, 3 is a piston, 4 is a slipper band, 5 is a swash plate, 6 is a rotating shaft, 7 is a casing, 8 is a suction pipe, and 9 is a discharge pipe.

The casing 7 has a cylindrical portion 7b connected at one end to the end plate 1a, and a front plate 7 connected to the other end.
c, and a sealed cavity 20 is formed inside thereof. The rotating shaft 6 passes through the front brake (7c) and extends across the sealed cavity 20, and one end thereof is connected to the end brake (7a).
(The other end is supported by a bearing 21, and the other end is a front brake)
7c by a bearing 22. A suction port 14 and a discharge port 17 are bored in the end plate 7a, and a suction pipe 8 is connected to the outer surface thereof so as to communicate with the suction port 14, and a discharge pipe 9 is connected so as to communicate with the discharge port 17. has been done.

Further, a valve grade 2 is provided on the inner surface of the end plate 7a.
is fixed, an arcuate suction boat 13 drilled in this valve plate 2 communicates with an intake port 14, and an arcuate discharge boat 16 bored in a dotted line with this suction boat 13 communicates with a discharge port 17. are doing. A cam holder 23 is fixed to the inner surface of the front plate 7c, and a convex spherical surface 5b on the back of the swash plate 5 is in sliding contact with the concave spherical surface 23a of the cam holder 23, and the swash plate 5 is rotated around its tilt axis by a control device such as a regulator (not shown). It is designed so that it can be tilted in the direction of the white arrow shown in FIG.

The cylinder block 1 is wedged around a rotating shaft 6, and a plurality of cylinders 10 (nine in the figure) are bored in the axial direction at predetermined intervals on the same circumference centered on the shaft center. There is.

One end of a piston 3 is slidably fitted into each of these cylinders 10 in a liquid-tight manner, and a spherical portion 11 formed at the other end of each piston 3 is engaged with a slipper pad 4 so as to be movable. ing. The retainer 24, which is in sliding contact with the slipper pad 4, engages with an arcuate surface 25a on the back of the piece 25, and a spring 26 is interposed between the front surface of the piece 25 and the back surface of the cylinder block 1. Thus, the front surface of the cylinder block 1 is pushed by the spring 26 and pressed against the valve plate 2, and at the same time, this reaction force pushes the slipper pad 4 through the piece 25 and the retainer 24.
is brought into pressure contact with the inclined surface 5a of the swash plate 5.

A cylinder chamber 15 is defined by the cylinder 10 and the piston 3, and this cylinder chamber 15 communicates with a cylinder boat 12 bored in the front face of the cylinder block l.

When the rotating shaft 6 is rotated in the direction of the solid arrow with the swash plate 5 tilted as shown in FIG. 6, the cylinder block 1 wedged on the rotating shaft 6 rotates. Then, the cylinder 1 drilled in the cylinder tab
The other end spherical portion 11 of the piston 3 is fitted into the inside of the piston 3.
rotates while slidingly contacting the swash plate 5° inclined surface 5a via the slipper pad 4, and the piston 3 reciprocates within the cylinder 10 accordingly. As a result, cylinder boat 12
is open to the suction boat 13 of the valve plate 2, that is, while the piston 3 moves to the right in FIG. The air is sucked into the cylinder chamber 15 through the air.

On the other hand, while the cylinder boat 12 is open to the discharge boat 16 of the valve plate 2, that is, while the piston 3 is moving to the left in FIG. It is discharged through the boat 16, the discharge port 17, and the discharge pipe 9.

If the swash plate 5 is tilted counterclockwise in FIG. 6 to increase the tilt angle of the inclined surface 5a, the stroke amount of the piston 3 will increase,
The amount of discharge per rotation of the rotating shaft 6 can be increased. The working fluid pressure in each cylinder chamber 15 is applied to the swash plate 5 via the piston 3 and the slipper pad 4, and the working fluid pressure in each cylinder chamber 15 changes as shown in the ninth section. That is,
The working fluid pressure in the cylinder chamber 15 rises to the discharge pressure Pd only after some time has passed after the cylinder chamber 15 reaches the bottom dead center B-D. −
Since the discharge pressure does not decrease to βS until some time has passed after reaching C, the area A and the opening shown by diagonal lines in the figure do not occur.

In order to reduce the noise of this fluid equipment, the cylinder port 12 is communicated with the discharge boat 16 via the notch 19 for a while after the cylinder chamber 15 has passed the bottom dead center R-D-C. The working fluid in the chamber 15 is pre-contracted and gently raised, and after the cylinder chamber 15 has passed the top dead center TDC, the cylinder port 12 is injected into the cylinder port 3 through the notch 18. When the working fluid in the cylinder chamber 15 is pre-expanded and gradually lowered by communicating with the cylinder chamber 15, the area A and the opening shown by diagonal lines increase.

(Problems to be Solved by the Invention) In the conventional axial piston pump described above, the working fluid pressure in each cylinder chamber 15 changes as shown in FIG. 5° clockwise around its tilting axis (the force that causes it to rotate is greater than the force that causes it to tilt counterclockwise. Therefore, the force that acts on the swash plate 5 based on the working fluid pressure in each cylinder chamber 15 As shown in FIG. 10, the sum total acts unbalancedly on the tilting axis of the swash plate 5, and generates a tilting torque that rotates the swash plate 5 clockwise around the tilting axis t21-. and swash plate 5
The torque required for control, that is, the control torque, must be made large enough to overcome the rotational torque caused by the pressure of the working fluid, resulting in a problem of poor controllability.

(Means for Solving the Problems) The present invention was invented in order to deal with the above-mentioned problems, and its gist is to provide a piston having one end fitted into each of a plurality of cylinders. The other end is brought into sliding contact with the inclined surface of the tiltable swash plate via the cylinder, so that it reciprocates in the axial direction, and at the same time, each cylinder chamber defined by the cylinder and the piston is connected to the valve plate. In an axial screw type fluid machine which is alternately connected to an open low-pressure boat and a high-pressure boat, the swash plate is rotated around its rotation axis based on the pressure of the working fluid in each of the cylinder chambers acting on the swash plate. A fluid pressure actuator is provided to generate a tilting force that counteracts the tilting force that causes the boat to tilt. This is an Akinyalpis F-type fluid machine characterized by introducing A-body pressure or high-pressure working fluid pressure.

(Function) In the present invention, the working fluid pressure or high-pressure working fluid pressure in the cylinder chamber communicating with the high-pressure boat is introduced to the fluid pressure actuator (thereby generating a rotational force that rotates the swash plate, and this tilting force causes the cylinder to rotate. The control torque is reduced by offsetting the tilting torque based on the indoor working fluid pressure.

(Example) One embodiment of the invention is shown at No. 1121.

A fluid pressure actuator 27a is provided on the front plate 7c.
27b is provided, and these plunges +28a, 28b pass through the cam holder 23, and their tips hit the top dead center TDC side or the bottom dead center B/DC side of the back convex spherical surface 5b of the swash plate 5. be brought into contact with Then, this fluid pressure actuator 2
7a and 27b are communicated with the discharge boat 16 and the suction boat 3 through channels 29a and 29b, respectively. The construction of the pump is similar to that of the conventional pump shown in FIGS. 6 and 6, and corresponding members are given the same reference numerals.

Therefore, when the rotating shaft 6 is rotated in the direction of the solid line arrow with the swash plate 5 tilted as shown in the figure to function as a pump, the swash plate 5 is receives clockwise torque around its tilt axis, but at the same time, discharge pressure, that is, high working fluid pressure is supplied from the discharge port 6 through the flow path 29a into the fluid pressure actuator 27a. , its plunger 28
a to generate a tilting force that tilts the swash plate 5 counterclockwise around its axis, and this tilting force generates a tilting torque based on the working fluid pressure in the cylinder chamber 15. cancel.

When discharging the working fluid in the opposite direction, the swash plate 5 is tilted as shown at a point t* VA in the figure. And the rotating shaft 6
When the boat 13 is rotated in the direction of the solid line arrow, the boat 13 becomes a discharge boat, the boat 16 becomes a suction boat, and they are switched, and top dead center TDC and bottom dead center BDC are also switched. In this way, the swash plate 5 receives a counterclockwise tilting torque around its tilting axis based on the pressure of the working fluid in each lower chamber 5, but the high-pressure working fluid is removed from the boat 13 which has become a discharge boat. is introduced into the fluid pressure actuator 2fb via the flow path 29b, and pushes the plunger 28b to generate a tilting force that tilts the swash plate 5 clockwise around its tilting axis.

When used as a motor, high-pressure working fluid is supplied from the boat 13 with the swash plate 5 tilted as shown by the solid line in the figure. Then, the rotating shaft 6 rotates in the direction of the solid arrow in the figure, and the low-pressure working fluid is discharged from the boat 16. Therefore, based on the pressure of the working fluid in each cylinder chamber 15, the swash plate 5 receives a rotational torque in a counterclockwise direction around its tilt axis.

At the same time, high-pressure working fluid is supplied from the boat 13 through the passage 29b to the fluid pressure actuator 27b, which pushes the plunger 28b to rotate the swash plate 5 clockwise around its tilting axis. generates a tilting force to Conversely, when the swash plate 5 is tilted as shown by the dashed line in the figure, high-pressure working fluid is supplied from the boat 16.Then, the rotating shaft 6 rotates in the direction opposite to the solid line arrow in the figure.
Based on the working fluid pressure in each cylinder chamber 15, the swash plate 5 receives a clockwise rotational torque about its tilt axis. In this case, high-pressure working fluid is supplied from the boat 16 to the fluid pressure actuator 27a through the channel 29a, and the swash plate 5
generates a tilting force that rotates the motor counterclockwise.

A second embodiment of the invention is shown in FIG.
In place of the fluid pressure actuators 27a and 27b of the embodiment, the top dead center of the concave spherical surface 23a of the cam holder 23 is
Cavities 30a, 30 on the C side and bottom dead center B-D-C side
b, and these cavities 30a.

30b are communicated with the bores 6.13 through channels 29a and 29b, respectively. When high-pressure working fluid is supplied to this cavity 30a, the swash plate 5 is tilted counterclockwise around its tilting axis, and when high-pressure working fluid is supplied to the cavity 30b, the swash plate 5 is tilted counterclockwise around its tilt axis. It is tilted clockwise around the tilt axis.

The other configurations and operations are similar to those of the first embodiment, and corresponding members are given the same reference numerals.

A third embodiment of the invention is shown in FIGS. 3-5. The fluid pressure actuator 27a is at the top dead center T-D-
The fluid pressure actuator 2 is connected to an opening 31a opening between the boats 16 and 13 on the C side via a flow path 29a.
7b is connected via a flow path 29b to an opening 31b that opens between the boats 16 and 13 on the bottom dead center B-D-C side. The rest of the structure is similar to that of the first embodiment, and corresponding members are given the same reference numerals.

When the rotating shaft 6 is rotated in the direction shown by the solid arrow with the swash plate 5 tilted to 4J[ shown in the figure, the working fluid is sucked from the boat 13 and discharged from the boat 1d.

When the cylinder boat 12 reaches the position shown in FIG. 4, that is, a position slightly before the top dead center TDC, the cylinder port 12 communicates with the opening 31a. Then, when the cylinder port 12 reaches position B, that is, the top dead center TDC, the cylinder port 12 separates from the boat 16 and starts communicating with the notch 19, and the cylinder chamber 1
The pressure inside 5 gradually decreases, and when the cylinder port 12 reaches the C position, the cylinder port 12 separates from the opening 31a. Thus, during this period, the pressure of the working fluid in the cylinder chamber 15 changes as shown in FIG. , is supplied to the fluid pressure actuator 27a via the m path 29a, and pushes the plunger 28a to move the swash plate 5 counterclockwise around its tilt axis.
Rotate it to generate rotational force.

By appropriately selecting the position of the opening 31a, the sum of areas A and C can be made equal to area C, thereby making it possible to substantially reduce the control torque required to control the swash plate to zero. Moreover, the working fluid pressure applied to the fluid pressure actuator 27a from the opening 31a changes in accordance with the inclination angle of the swash plate 5. Therefore, regardless of the inclination angle of the swash plate 5, the control torque can be substantially controlled. It can be zero. Other operations are similar to those in the first embodiment.

(Effects of the Invention) In the present invention, the working fluid pressure or high-pressure working fluid pressure in the cylinder chamber communicating with the high-pressure boat is guided to the fluid pressure actuator, and the swash plate is tilted around its tilting axis by this fluid pressure cylinder. This tilting force can offset the tilting torque that tilts the swash plate about its tilting axis based on the working fluid pressure in each cylinder chamber. In this way, the control torque required to control the swash plate 5 is small, and the control device such as the regulator can be downsized and the controllability can be improved.

[Brief explanation of the drawing]

Fig. 1 is a schematic system diagram showing a first embodiment of the present invention, Fig. 2 is a schematic system diagram showing a second embodiment of the invention, and Fig. 3 is a schematic system diagram showing a second embodiment of the present invention.
5 to 5 show a third embodiment, FIG. 3 is a schematic system diagram, FIG. 4 is a partial front view of the valve plate, and FIG.
The figure is a diagram showing changes in working fluid pressure within the cylinder chamber. Figures 6 to 1O show an example of a conventional axial piston type pump, with Figure 6 being a longitudinal sectional view, Figure 7 being a view taken along the line ■-■ in Figure 6, and Figure 8 being a view taken along the line ■-■ in Figure 6. 110■-1
Figure 9 is a diagram showing changes in the working fluid pressure in the cylinder chamber. Cylinder 10, piston 3, slipper pad 4, swash plate 5, inclined surface 58, cylinder chamber 15, valve plate 2, low pressure; tote or high pressure port 13.1b, Fig. 6, 9 Figure 10

Claims (1)

[Claims] One end of each piston is fitted into a plurality of cylinders, and the other end is brought into sliding contact with the inclined surface of a tiltable swash plate via a slipper pad, thereby reciprocating the cylinders and the pistons in the axial direction. In an axial piston type fluid machine in which each cylinder chamber limited by A fluid pressure actuator is provided that generates a tilting force that opposes the tilting force that causes this to tilt around its tilting axis, and the hydraulic actuator is provided with a working fluid pressure in the cylinder chamber that communicates with the high pressure port. An axial piston type fluid machine characterized by introducing high working fluid pressure.