JP2003113776A - Variable displacement type axial piston unit with swash plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable displacement type axial piston unit capable of minimizing the wear caused by a mechanical friction. SOLUTION: This unit comprises an extension part 92 branching in three ways, and a universal joint 90 furnished at the end of the extension part with a bearing outer ring 94 coupled in such a way as rotatable in the circumferential direction of the extension part 92 and foldable in its axial direction is mounted on a shaft 40, and a shoe holder assembly 80 including a joint hole 82 to admit insertion of the universal joint is coupled with the swash plate 70 slidably thereon, and the power is transmitted or coupled while the bearing outer ring 94 complies with the position of the shoe 81 varying in the process that the shoe 81 slides along the swash plate 70 and rotates.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heavy-duty equipment and a variable displacement type swash plate type axial piston unit used in various industrial fields, and more specifically, it converts a rotary motion into a linear motion or rotates a linear motion of a piston. To widen the diffraction angle of the piston rod flexibly connected to the shoe that slides and rotates on the swash plate when the piston unit reciprocates while sliding and rotating on the swash plate that has an inclined surface in order to convert into motion. It is possible to increase the tilt angle of the swash plate by configuring so that the piston can move in parallel along the same axis as the cylinder axis and not being restricted by the diffraction angle of the piston rod. Variable displacement swash plate type that can increase the stroke distance of the piston and thereby increase the pumping flow rate of the fluid and the rotating force of the shaft · The relate Shall piston unit.

[0002]

2. Description of the Related Art Generally, a swash plate type is a rotary plate (swash plate) provided on a shaft that applies a rotational force to the shaft to make a spiral rotation about the axis of the shaft or an oblique rotation. After fixing the plate, the cylinder barrel including a plurality of cylinders that are rotated together with the shaft is rotated so that the piston rotates while sliding on the inclined surface of the swash plate so that the piston reciprocates. .

The variable displacement type swash plate type axial piston unit has different functions depending on whether it is passive or active.

That is, in the active state, when a fluid is introduced into the cylinder at a constant pressure, the rotational force generated when the piston reciprocates and slidably rotates along the inclined surface of the swash plate is generated. It can be used as a hydraulic motor by outputting it by a shaft and supplying the rotational power to a device requiring a rotational force.

On the other hand, in the passive case, a rotational force is input to the shaft, which serves as a hydraulic pump that pumps the fluid in the cylinder to the outside while the piston reciprocates.

Such a variable displacement type swash plate type axial piston unit is widely used in excavators, four cranes, bulldozers and other heavy equipment or in various industrial fields.

The term "piston unit" as defined in the present specification includes the meaning that two functions can be performed together as described above. That is, it includes a device for pumping a fluid by a pumping motion and a device for generating rotational power by a piston motion.

Generally, in a swash plate type hydraulic pump (or compressor) and a motor, the swash plate and rotation are stopped by the rotation of the cylinder barrel and piston unit assembly, and the piston oscillates within a certain angle. Since it has to move, a trunnion type in which a switching shaft is connected to the center of the swash plate to prevent rotation of the swash plate and a cradle type in which both sides of the swash plate and the lower surface are placed in a semi-cylindrical shape These have a complicated structure in terms of workability and miniaturization.

[0009] Examples of the conventional swing swash plate type variable displacement compressor proposed include Japanese Utility Model Publication No. 62-183082, Korean Patent Publication No. 1996-14656, and Korean Patent Publication No. 1999-6228. And those described in. Said Nihon Kaikai Sho 62-1830
In the compressor of No. 82, the rotary driving body is connected to the rotary support body fixedly fitted to the shaft so as to be inclined in the front-rear direction by the connecting pin, and the rotary drive body swings obliquely. A plurality of pistons that support a plate and are inserted in parallel in a plurality of cylinder bores at a predetermined interval from each other, and a piston rod interposed between the swing swash plate and the swash plate, respectively It is designed to be converted into a reciprocating motion.

Further, an elongated hole for slidably guiding the connecting pin is formed in the rotary support, allowing the tilting motion of the rotary drive and the swing swash plate to allow the compression stroke of the piston. Is almost constant at the end of (top clea
In order to maintain the rance), the feature is that the top dead center position of the swing swash plate is not displaced in the front-rear direction even if the inclination angle changes.

Also, in the latter hydraulic pump disclosed in the Korean patent, the piston extends, and the extended portion is in direct contact with the inclined surface or the swash plate is interposed on the inner surface, so that the sliding motion and the rotary motion are simultaneously performed. As a result, the rotary motion is converted into the linear motion, and the piston can reciprocate.

The operating principle of the variable displacement type swash plate type axial piston unit used in recent years will be described in more detail with reference to FIGS. 1 to 4.

First, as shown in FIG. 1, while the piston 53 in the cylinder barrel 50 reciprocates in the axial direction of the shaft 40, the rotational force is transmitted to the cylinder barrel 50 by the side force of the piston 53.

That is, based on the order of power transmission,
In the function as a motor that generates a rotational force, when the fluid from the fluid inlet 62 in the fluid flow path block 60 flows into the cylinder, the shoe holder assembly 80 tilts the swash plate 70 while the piston 53 reciprocates. The cylinder block 50 is rotated along the surface, and the cylinder block 50 is rotated together by the side force generated by the rotation.
Rotate 0.

In the process of power transmission when used as a hydraulic pump for pumping fluid, when power is input to the free end of the shaft 40, the cylinder block 50 connected to the spline 42 of the shaft 40 rotates and the inside of the cylinder 51 is rotated. While the shoe holder assembly 80, to which the free end of the piston 53 is coupled, rotates along the inclined surface of the swash plate 70, the piston 53 reciprocates to pump the fluid in the cylinder 51.

As described above, in the conventional variable displacement type swash plate type axial piston unit, the shoe holder assembly 80 is variable along the spherical surface 41a of the spherical body 41 connected to the shaft 40 when the cylinder block is rotated. Sliding and rotating, power is transmitted by the side force of the cylinder block and the piston.

The piston 53 having such a structure and the inner surface of the bore of the cylinder barrel 50 generate a great amount of friction, and the frictional force hinders the reciprocating motion of the piston 53 to lower the mechanical efficiency. Generation and early wear of parts.

As an effort to solve such a problem to some extent, the entire cylinder barrel 50 is made of a copper (Cu) material or a bush made of copper is inserted into the inner surface of the bore for use. Increase and economic burden becomes a big problem.

In addition, as shown in FIG. 3, when the piston 53 and the shoe 81 are connected to each other to perform a swinging motion, the inclination 7
The size of the tilt angle of 0 is limited to the range in which the shoe 81 can swing, and limits the improvement of the tilt angle, and the range is about 14 ° or less.

The inclination angle of the swash plate 70 can be increased by changing the stroke of the piston 53, that is, the stroke length of the piston 53, even if the volume of the piston 53 is the same in the hydraulic pump or the hydraulic motor. It means that it can be extended.

However, when the inclination angle of the swash plate 70 becomes 14 ° or more at the maximum, the diffraction angle between the spherical axis 53a of the piston 53 and the shoe 81 becomes large, and the piston 53 is converted from the linear motion to the oblique motion. As a result, a serious problem that serious wear or damage occurs on the surface where the piston 53 and the cylinder 51 contact each other.

After all, such a problem is caused by abruptly shortening the life of the cylinder 51 and the piston 53.
There are restrictions on the angle design of the swash plate 70,
The diffraction angle between the shoe and the spherical axis of the piston 53 directly affects the reciprocating motion of the piston 53.

Therefore, when the diffraction angle of the spherical surface 53a of the piston 53 connected to the shoe 81 can be adjusted to a larger range, the piston 53 can reciprocate in parallel along the axial direction of the cylinder 51. The wear of the cylinder 51 and the piston 53 can be prevented to the maximum, and the angle of the swash plate 70 can be adjusted to a larger inclination angle than the conventional one, so that the stroke of the piston 53 is extended. Therefore, in the case of a hydraulic pump, the pumping flow rate of the piston 53 can be improved, and in the case of a motor, its rotational force can be strengthened.

In order to solve such a problem, the swash plate 7
The inclination angle of 0 indicates the reciprocating movement of the piston 53, the stroke length, the spherical shaft 53a of the piston unit and the shoe 81.
It can be said that the biggest problem to be solved is that the diffraction angle with and must not be affected.

After all, when the angle of the swash plate 70 or the friction plate 72 attached thereto is adjusted upward, it is necessary to prevent the reciprocating motion of the piston 53 from being affected, and the inclined surface of the swash plate 70 should not be affected. There is a demand for variably adaptable power transmission means so that power can be transmitted with a margin in accordance with the position of the shoe 81 whose position continuously variably changes along the position.

[0026]

SUMMARY OF THE INVENTION The present invention was devised to solve the above-mentioned problems, and the purpose thereof is to increase the stroke angle of the swash plate so that the stroke length of the piston unit can be extended. By providing a swash plate with a larger upward adjustment, the upward adjustment of the inclination angle of the swash plate keeps the reciprocating motion of the piston unit interlocking with the shoe parallel along the cylinder axis, and thus mechanical friction is maintained. A universal joint type variable displacement swash plate type axial piston that minimizes wear due to vibration and transmits power while variably responding to the position of the shoe that rotates along the swash plate when transmitting power between the shaft and shoe. To provide a unit.

Another object of the present invention is to use a universal joint to variably connect transmission media that transmit power when converting rotational force into linear motion or converting linear motion into rotational force. By connecting with a universal joint like this, the transmission of power becomes free,
Accordingly, the object is to provide a variable displacement swash plate type axial piston unit in which the tilt angle of the swash plate can be adjusted upward.

Further, another object of the present invention is to variably and correspondingly transmit power through a universal joint so that the tilt angle of the swash plate can be adjusted upward so that the stroke length of the piston unit can be adjusted. Therefore, the pumping flow rate of the piston unit is improved and the rotational force of the drive shaft is remarkably improved, so that the variable displacement swash plate type axial piston unit is provided.

[0029]

A variable displacement swash plate type axial piston unit for achieving the object of the present invention comprises a bearing block for bearing a shaft having a spline on the axis, a fluid inlet and a fluid outlet. A housing provided with a fluid flow path block and a body having a cylindrical chamber inside, and a swash plate fixed to the inner surface of the bearing block and having an inclined surface inclined at a predetermined angle,
A cylinder barrel having a plurality of fluid passages selectively communicating with the fluid inlet or the fluid outlet, a cylinder barrel having a plurality of cylinders, a spring provided on a shaft inside the cylinder barrel, and a swash plate. A shoe holder assembly including a plurality of shoes rotatably coupled to the respective shafts of the respective pistons slidably mounted in the cylinder. The shaft is rotated in the circumferential direction of the shaft to transmit power to and from the shaft, and is freely rotated in the circumferential direction of the extension at each end of the extension extending in three directions. And a universal joint having a bearing outer ring rotatably coupled in the axial direction is coupled to the inner surface of the shoe holder assembly. Preparative may form a joint hole to be inserted, wherein a surface of the bearing outer ring is slidably coupled to the joint hole so as to correspond to the variable position of the shoe.

In the present invention, the swash plate is fixed and the shoe holder assembly having a plurality of shoes is rotated by the shaft. The shoe holder assembly is rotated on the shaft in the circumferential direction of the shaft and branched into three directions. After connecting a universal joint with a bearing outer ring that is diffracted in the axial direction rotatably in the circumferential direction of the extension to the end of the extended part, it is slidably connected to the surface of the swash plate so as not to be separated. This is achieved through a shoe holder assembly having a joint hole into which the universal joint is inserted.

In the above-described invention, a joint which is rotatably rotatable in the circumferential direction with respect to the axis of the extension and which is diffracted in the axial direction is provided at the end of the extension which is branched from the universal joint in three directions. By forming the outer ring of the bearing, which is connected to the shoe holder assembly, on the extension part of the bearing, the bearing is adjusted according to the position of the shoe while the shoe rotates while sliding along the swash plate. The outer ring is capable of transmitting power while diffracting.

Therefore, even if the position of the shoe changes, the power can be transmitted between the shoe and the universal joint. This allows the shoe to rotate even if the tilt angle of the swash plate is adjusted upward. Further, the moving distance of the shoe is that the inclined surface of the swash plate is upward, that is, 14 °.
You will be able to adjust upwards from about 30 °. In the preferred embodiment of the present invention, the angle is 20 °.

Furthermore, another rotatable joint is provided between the shoe and the piston unit so that the linear movement of the piston unit's own axis does not move in the oblique direction as in the conventional case due to the increase in the stroke of the shoe. By connecting the piston rods that it has, it becomes possible to perform the pumping operation and the rotating operation without affecting the reciprocating motion of the piston unit.

After all, it is possible to generate a rotary power by linearly reciprocating in a state where no lateral force acts on the piston,
By reducing the length of the piston by not utilizing the side force of the piston, and by connecting it to the shoe through the piston rod even if shortened, the angle at which the shoe can swing can be increased to 20 °. Not only the output of the hydraulic pump or the motor can be improved in the stroke of the large piston, but also friction due to the side force of the piston can be avoided, so that the mechanical efficiency can be increased.

Further, in the present invention, in the variable displacement type swash plate type axial piston unit in which the swash plate is rotated together with the shaft, the shaft is rotated in the circumferential direction of the shaft, and the circumference of the extension is branched into three directions. A universal joint having a bearing outer ring that is rotatably rotated in the axial direction and diffracted in the axial direction is fixed, and joint holes formed in three directions in which the universal joint is inserted are formed on a swash plate. Half of the shaft is rotatable in the circumferential direction of the shaft, a cylinder block including a plurality of cylinders is fixed in the housing, and a free end of a reciprocating piston in the cylinder surrounds an edge of the swash plate. It is achieved by sliding assembly.

In the case of the present invention described above, the swash plate rim is slidably surrounded, and when the shaft rotates, the universal joint rotates the swash plate and the piston reciprocates in the cylinder that rotates together. The load generated when the swash plate is rotated can be reduced.

Therefore, even if the angle of the swash plate is adjusted upward, the power transmission between the shaft and the swash plate is performed by the universal joint, so that not only the load is very small but also the angle of the swash plate can be adjusted upward so that the piston Pumping flow rate and shaft torque can be improved.

That is, in order to operate the pump or the motor, when the shaft is first rotated or the piston unit is operated, the load increases as the inclination angle of the swash plate increases, but in the case of the present invention, Since power is transmitted by sliding between the swash plate and the bearing outer ring, there is an advantage that the load is relatively greatly reduced.

[0039]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of a variable displacement type swash plate type axial piston unit according to the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 5 is a cross-sectional view showing the internal structure of the variable displacement type swash plate type axial piston unit according to the present invention. The same reference numerals are used for the same parts as the conventional constituents.

In FIG. 5, reference numeral 20 indicates a housing of a variable displacement type swash plate type axial piston unit.

The housing 20 includes a bearing block 30 bearing a shaft 40, a cylinder barrel 50 rotating with the shaft 40, and the cylinder barrel 5.
A cylindrical chamber 1 in which a fluid flow path block 60 composed of a manifold through which a fluid flows in or out of a cylinder 51 of 0, and the cylinder barrel 50 is provided inside
And a body portion 10 having 0a.

The shaft 40 is rotatably disposed in the bearing block 30 and the fluid passage block 60 via bearings 31 and 61, respectively, and a spline 42 is formed in a certain section. Inside the bearing block 30,
The swash plate 70 is fixed by the fastening pins 32. Swash plate 7
No. 0 is equipped with a friction plate 72 made of cemented carbide having an inclined surface 71 inclined by about 20 ° on the surface.

Further, the shaft 40 is an assembly in which a plurality of shoes 81, preferably nine shoes 81, which are slidably disposed on the inclined surface are arranged in a central portion of the shaft 40 at regular intervals. I am doing it. Each of the shoe holder assemblies 80 includes a triangular branched joint hole 82 therein as shown in FIGS. 7 and 11, and is disposed on the friction plate 72 of the swash plate 70 as shown in FIG. Is installed,
An upper portion thereof is covered with an annular clip 73. The annular clip 73 is fastened to the swash plate 70 with bolts.

The annular clip 73 guides the shoe holder assembly 80 to have a concentric radius of rotation when the shoe holder assembly 80 is rotated along the inclined surface 71 so as not to be separated.

As shown in FIG. 4, the cylinder barrel 50 includes respective cylinders 51 each having a fluid passage 52 communicating with the fluid inlet 62 and the fluid outlet 63 of the fluid channel block 60 therein. A piston 53 is slidably inserted in the cylinder 51. The cylinders 51 have axes parallel to each other. The cylinder barrel 50 is slidably connected to the spline 42 in the axial direction of the shaft 40.
It will not rotate in the circumferential direction of 0 unless the shaft 40 is rotated. A compression spring 54 is provided inside the cylinder barrel 50 to bias the cylinder barrel 50 toward the fluid flow path block 60.

The piston 53 is, as shown in FIG. 8a,
The free end may be provided with a spherical shaft 53a integrally formed with itself, or a spherical spherical bearing 53b may be provided on the inner surface of the central portion as shown in FIG. 8b. Here, in the power transmission in which the form of the piston 53 is intended in the present invention,
This is because all the pistons 53 described above can be adopted. An example of the operation thereby will be described in more detail below.

The spherical bearing 81a is inserted in the spherical surface 53a of the piston 53 and diffracted, or the spherical bearing 53b provided at the free end of the piston 53 and the spherical bearing 81a of the shoe 81 are connected to the piston rod 83. Can be connected to each other via. Of course the above piston rod 8
Both end portions of 3 have spherical bearings 53b and 81a, respectively.
And has spherical axes 83a and 83b that are freely diffracted. The spherical bearing 81a of the shoe 81 is provided with a fine flow passage 85 penetrating toward the surface of the swash plate 70 in contact with the friction plate 72, so that the lubricating oil can flow in.

The piston rod 83 has a predetermined length and is provided with a fine flow passage 84 that penetrates in the axial direction thereof. Lubricating oil also flows into the fine flow passages 84 due to the internal pressure generated when the piston 53 reciprocates, and the mechanical friction generated from the shoes 81 and the friction plates 72 is minimized.

The universal joint 90 is for converting a linear motion into a rotary motion, that is, the cylinder 51.
When the fluid is forced to flow into the piston, the piston 53 reciprocates to transmit the rotational force generated when the shoe 81 rotates while sliding on the friction plate 72 of the swash plate 70 to the shaft 40, Alternatively, for converting a rotational movement into a rectilinear movement, that is, for transmitting a rotational force input to the shaft 40 from the outside to a shoe 81 that is interlocked with the piston 53 and the piston rod 83 so that the piston 53 can rectilinearly move. It is a medium.

The universal joint 90 is shown in FIG.
As shown in 0, through the through hole 91 in the central portion, the shaft 4
It is firmly fixed on the shaft 0 and rotates integrally with the shaft 40. The universal joint 90 has extension parts 92 extending in three radial directions with respect to the through hole 91, and spherical ball bearings 93 are provided at the ends of the extension parts 92, respectively.
A bearing outer ring 94, which surrounds the spherical ball bearing 93 and is rotatably coupled to the spherical ball bearing 93, is coupled to the spherical ball bearing 93. This bearing outer ring 9
4 has at least flat sliding surfaces facing each other.

Therefore, the universal joint 90
Is capable of rotating in the circumferential direction of the shaft 40, transmitting or receiving power for rotating the shoe holder assembly 80 in the circumferential direction of the shaft 40, and the bearing outer ring 94 of the extension 92. Since it is freely rotated in the circumferential direction and is also diffracted in the axial direction, even if the surface of the joint hole 82 in contact with the bearing outer ring 94 slides and slips, it can be dealt with.

That is, since the bearing outer ring 94 can be diffracted by the spherical ball bearing 93, there is a margin to be able to tilt in all directions up to an angle equal to or greater than the tilt angle of the swash plate 70. The bearing outer ring 94
The outer surface thereof has a quadrangular shape, and one side surface thereof is inserted into the joint hole 82 of the shoe holder assembly 80.

Therefore, when the universal joint 90 rotates, its rotational force, that is, the bearing outer ring 94 of the universal joint 90 which rotates in the radial direction of the shaft 40 rotates the shoe holder assembly 80, and conversely the reciprocating motion of the piston 53. Thus, while the shoe holder assembly 80 rotates along the swash plate 70, the rotational force thereof is transmitted to the bearing outer ring 94 to rotate the shaft 40.

In the present invention, as disclosed in Korean Patent Publication No. 1996-14656, the shaft 40 and the swash plate 70 are rotated together, and both edges of the swash plate 70 are slidably connected. When the swash plate is rotated when the shaft 40 rotates to reciprocate the piston unit, the swash plate 70 and the shaft 40 are separated, and the universal joint 90 of the present invention is inserted on the swash plate. The angle of the swash plate can be adjusted upward by forming 82 and disposing the universal joint 90 on the shaft 40.

In this case, in order to operate the pump or the motor, when the shaft is first rotated or the piston unit is operated, the load increases as the tilt angle of the swash plate increases. The power is transmitted by sliding between the swash plate and the bearing outer ring, so that the load is relatively greatly reduced.

Accordingly, in the variable displacement type swash plate type axial piston unit according to the present invention, power is directly transmitted by the shoe holder assembly 80 and the universal joint 90 connected on the shaft 40 when the cylinder block rotates. Since it rotates together with the cylinder block 50, no lateral force is generated.

Hereinafter, an operation example of the variable displacement type swash plate type axial piston unit according to the present invention having the above-described structure will be described.

First, the case where the present invention is used as a hydraulic pump for fluid pumping will be described.

As shown in FIGS. 5 to 7, the shaft 40
When external power, that is, rotational force is input to
The shaft 40 starts to rotate. Due to the rotation of the shaft 40, the universal joint 90 and the cylinder barrel 50 rotate at the same time, and the bearing outer ring 94 rotates while being in contact with the inner surface of the joint hole 82.

In this case, the shoe is rotated according to the angle of the inclined surface of the swash plate 70 as shown in FIG. 12, but is rotated along the friction plate 72 of the swash plate 70 as shown in ac. However, since the shoe 81 is moved closer to or farther from the cylinder 51, the sliding angle between the joint hole 82 and the sliding surface of the bearing outer ring 94 is deformed.

That is, since the shoe rotates while being guided on the swash plate 70, even if the shoe rotates, it is located at the highest point a of the swash plate 70 or at the lowest point c. Also, since the angle at which the shoe 81 is in close contact with the swash plate 70 does not change and there is a difference only in the distance from the cylinder 51, the connection surface with the bearing outer ring 94 does not change significantly.

However, when the position of the shoe 81 is changed, the shoes 81 rotate while being in contact with each other while being diffracted by the spherical ball bearing 93 of the bearing outer ring 94 which comes into contact with the shoe holder assembly 80.

Eventually, the rotating rotational force acts on the surface of the bearing outer ring 94, and it is slipped and diffracted to come into contact with the shoe 81 regardless of its position change.

The rotation of the rotating shoe holder assembly 80 causes the position to change by a distance between a and c in FIG. 12, and the piston 53 and piston rod 83 having their own shafts reciprocate while rotating. Get to exercise. Therefore, while the cylinder barrel 50 rotates together with the rotating piston rod 83, the fluid passage 52 communicates with the fluid inlet 62 of the fluid flow path block 60 as shown in FIG. 4, and the fluid rapidly flows into the cylinder 51. .

In this case, the piston 53 is the cylinder 51.
It starts from the time when it retreats from. That is, FIG. 4 and FIG.
2, the position of the shoe 81 on the swash plate 70
Is a ₁From position c₁Initially when rotating while sliding to position
Of a₁Fluid enters the fluid flow path block 60 from the position
The port 62 and the fluid passage 52 of the cylinder barrel 50 gradually
A large number of cylinders 51 connected to each other, that is, four cylinders
The fluid begins to flow into the linder 51, and
After being completely communicated with each other, it was cut off at point c
Become. At this time, the shoe reaches the lowermost position of the swash plate 70.
And the piston 53 is located at the bottom dead center.
It

Thereafter, the cylinder barrel 50 is rotated by the continuously rotating shaft 40, and the cylinder 51 is slid from the point c to the point a while the above operation is reversed to shut off the fluid inlet 62. The fluid discharge port 63 and the fluid passage 52 are communicated with each other, and the piston 5
The fluid is discharged by the pumping operation of 3.

In this process, the piston rod interposed between the shoe 81 and the piston 53 can reciprocate in the oblique direction with respect to the axis of the cylinder 51. However, the spherical joints on both sides diffract by themselves as the piston 53 reciprocates while diffracting.
3 and the slip surface of the cylinder 51 are not worn and reciprocate. Such an operation is performed while power is input from the outside to the shaft 40. Therefore, the fluid can be pumped.

On the contrary, the action by the operation when the present invention is adopted as the function of the hydraulic motor for generating the rotational power will be described.

In this case, when the fluid is forcibly injected into the fluid inflow port 62, the fluid flows into the fluid passage 52 of the cylinder 51 which communicates with the fluid inflow port of the fluid flow path block 60, so that the piston 53 is moved. It will be pushed and pushed out. When the piston 53 retracts, the piston rod 83
Alternatively, the spherical axis 53 of the piston unit having its own axis
When a and the shoe 81 both retract backward, they rotate while sliding along the slope of the swash plate 70.

The rotational force generated at this time is due to the large number of shoes 81.
Simultaneously rotate the cylinder barrel 50, and the shoe reversely urges the bearing outer ring 94 of the universal joint 90 to rotate the shaft 40.

Of course, the rotating cylinder barrel 50
The fluid inflow and outflow of the fluid are simultaneously performed by continuously and simultaneously performing the operation of selectively communicating or blocking the fluid passage 52 inside the fluid inflow opening 62 or the fluid exhaust opening 63. Therefore, the fluid is transferred to the cylinder 51
Then, the shaft 40 is forced to flow into the shaft 40 to generate a rotational force on the shaft 40.

As described above, the variable displacement type swash plate type axial piston unit according to the present invention, which can be used both as a hydraulic pump and a motor, is capable of pumping fluid by rotational power or generating rotational force by hydraulic power. become. Further, since very frequent friction is generated at the joints at both ends of the piston rod 83, the wear is minimized by injecting the lubricating oil through the fine passages in order to prevent the wear at the diffractive portion.

As shown in FIGS. 5 and 8, a spherical ball bearing is connected to the short piston 53 and the piston rod 83, and a small diameter capillary channel is formed in the piston 53 to support the piston 53. By receiving the supplied pressure oil and supplying it to the pocket portion of the spherical ball bearing, it is possible to minimize the frictional force even when the piston 53 and the piston rod 83 are brought into close contact with each other by a large load and move.

[0075]

As described above, according to the present invention, since the angle range due to the diffraction between the conventional piston 53 and the shoe for limiting the inclination angle of the swash plate 70 can be diffracted to a larger angle, the movement of the piston 53 can be changed. It is possible to reciprocate in parallel along the axis of the swash plate, and the angle of the swash plate 70
It can be adjusted upward from 4 ° to 20 °, and by extending the stroke of the shoe 81 that rotates while sliding on a swash plate, it can have a larger capacity than a conventional hydraulic pump or motor. is there.

After all, in transmitting the rotational power of the variable displacement type swash plate type axial piston unit, the friction with the inner surface of the bore of the cylinder barrel 50 is minimized by not utilizing the side force of the piston 53 or the piston rod 83. Since there is no need to provide the same bush on the inner surface of the bore to prevent sticking due to lateral force, and spherical ball bearings are provided on both sides of the piston rod 83, mechanical friction to the main moving parts is minimized. The mechanical efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the internal structure of a conventional variable displacement swash plate type axial piston unit.

FIG. 2 is a sectional view of a conventional axial variable displacement type swash plate type axial piston unit.

FIG. 3 is a cross-sectional view of a piston unit side force action in a conventional axial variable displacement type swash plate type axial piston unit.

FIG. 4 is a cross-sectional view of essential parts showing a fluid circulation process during operation of a conventional axial variable displacement type swash plate type axial piston unit.

FIG. 5 is a longitudinal sectional view showing the internal structure of a variable displacement swash plate type axial piston unit according to the present invention.

FIG. 6 is a sectional view showing a form of power transmission between a shaft and a shoe holder assembly by a universal joint according to the present invention.

FIG. 7 is a perspective view of a shoe holder assembly according to the present invention.

8A is a cross-sectional view of a piston unit having a spherical shaft in itself, and FIG. 8B is a cross-sectional view showing an embodiment of a piston unit having a spherical bearing in the piston unit.

FIG. 9 is a sectional view of a piston rod diffractively coupled between a shoe and a piston unit according to the present invention.

FIG. 10 is a sectional view of a universal joint according to the present invention.

FIG. 11 is a sectional view showing an assembled state of the universal joint and the shoe holder assembly of the present invention.

FIG. 12 is a cross-sectional view of essential parts showing a stroke of a shoe whose position is variable according to the present invention and a stroke of a piston rod communicating with the shoe.

[Explanation of symbols]

10 torso 10a chamber 20 housing 30 bearing block 31 bearing 32 Fastening pin 40 shaft 42 splines 50 cylinder barrel 51 cylinders 52 fluid passage 53 Piston unit 53a spherical axis 53b spherical bearing 54 spring 60 fluid flow path block 60a bearing 62 fluid inlet 63 Fluid outlet 70 Swash plate 71 inclined surface 72 Friction plate 73 Ring Clip 80 Shoe holder assembly 81 shoe 81a spherical bearing 82 Joint Hall 83 Piston rod 83a, 83b spherical axis 84, 85 Fine flow path 90 Universal joint 91 through hole 92 Extension 93 Spherical ball bearing 94 bearing outer ring

Continued front page    (71) Applicant 500 525494             171, Jang-Dong, Yusu             ng-gu, Taejon, Kore             a (71) Applicant 302044339             Na, Kyunbae             South Korea, Kyunsan-namdo, Kimha             D, Jin Aedon, 297-2 (72) Inventor Han, Young Mok             Republic of Korea, Taejeong, Yousang, Ja             Ndon 171 (72) Inventor Na, Kumbae             South Korea, Kyunsan Namdo, Kimha             D, Jin Aedon, 297-2 F term (reference) 3H070 AA01 BB04 BB06 BB25 CC07                       DD92                 3H084 AA08 AA16 BB09 CC21 CC56

Claims (9)

[Claims] 1. A bearing block for bearing a shaft having an axial spline, a housing having a fluid passage block having a fluid inlet and a fluid outlet, and a body having a cylindrical chamber therein, and the bearing. A cylinder provided with a plurality of cylinders, which has a swash plate fixed to the inner surface of the block and having an inclined surface inclined at a predetermined angle, and each fluid passage selectively communicating with the fluid inlet or the fluid outlet. A barrel, a spring provided on a shaft inside the cylinder barrel, and a pivotally movable shaft of each piston slidably coupled to the swash plate and slidably provided in the cylinder. A shoe holder assembly including a plurality of shoes coupled to the front shoe for transmitting power between the shoe holder assembly and the shaft. The shaft is rotatably connected in the circumferential direction of the shaft, freely rotated in the circumferential direction of the extension, and rotatably in the axial direction at each end of the extension extending in three directions. A universal joint having a bearing outer ring is coupled to the inner surface of the shoe holder assembly to form a joint hole into which the universal joint is inserted so that the surface of the bearing outer ring corresponds to the variable position of the shoe. Variable capacity swash plate type axial piston unit that is slidably connected to the joint hole. 2. The variable displacement swash plate type axial piston unit according to claim 1, wherein a free end of the piston is rotatably coupled to the shoe. 3. A fine flow path is formed for lubrication on a surface of the shoe where the inner surface of the spherical bearing is in contact with the swash plate, and lubricating oil flows into the fine flow path. The variable displacement swash plate type axial piston unit according to claim 2. 4. A piston rod is connected between the shoe and the piston so that the piston can reciprocate in parallel with the center line of the cylinder when the piston reciprocates. 2. The variable displacement type swash plate type axial piston unit according to claim 1, wherein the variable capacity type swash plate type is rotatably coupled. 5. The fine oil passage is formed in the axial direction of the piston rod, and the lubricating oil flows into the rotating portion of the piston and the shoe through the fine air passage. Variable displacement swash plate type axial piston unit. 6. The variable displacement swash plate type axial piston unit according to claim 1, wherein a free end of the piston is rotatably coupled to the shoe of the shoe holder assembly. 7. The variable displacement swash plate type axial piston unit according to claim 1, wherein the bearing outer ring of the universal joint is diffractable with respect to the axis of the extension thereof. 8. A bearing block for bearing a shaft having a spline on its axis, a housing having a fluid flow path block having a fluid inlet and a fluid outlet, and a body having a cylindrical chamber therein, and the shaft. A swash plate integrally rotatably coupled with a predetermined inclined surface, and a cylinder barrel having a plurality of cylinders, each cylinder having a fluid passage selectively communicating with the fluid inlet or the fluid outlet, A variable displacement type inclination comprising a spring interposed on the shaft inside the cylinder barrel, and respective pistons slidably coupled to the edge surface of the swash plate and slidably coupled to the inside of the cylinder. In a plate type axial piston unit, the shaft and the swash plate are rotated separately in order to transmit power between the swash plate and the shaft. And an end portion of the extension part which is rotated in the circumferential direction on the shaft and is divided into three directions, is composed of a bearing outer ring rotatably rotatable about the axis line in the circumferential direction. A universal joint and a swash plate having a joint hole into which the universal joint is inserted are rotatably coupled to the shaft so that power can be transmitted between the shaft and the swash plate by the universal joint. A characteristic variable displacement swash plate type axial piston unit. 9. The variable displacement swash plate type axial piston unit according to claim 1, wherein the swash plate has an inclination angle of 14 ° to 30 °.