KR100991513B1

KR100991513B1 - Piston assemblies in hydraulic pump and motor having a filter therein

Info

Publication number: KR100991513B1
Application number: KR1020100069116A
Authority: KR
Inventors: 이용범
Original assignee: 한국기계연구원
Priority date: 2010-07-16
Filing date: 2010-07-16
Publication date: 2010-11-04

Abstract

The present invention relates to a filter-embedded hydraulic pump and a motor piston assembly, and more particularly, to a piston assembly installed in a swash plate type hydraulic pump and a motor and in contact with a swash plate to rotate and reciprocate. When a small amount of oil flows into the positive pressure bearing side and lubricates the shoe and the swash plate, it prevents the solid friction of the shoe and the swash plate from being damaged by the foreign matter contained in the high pressure oil. To this end, a filter member is provided inside the piston to allow a small amount of positive pressure bearing to flow after the high pressure oil is filtered by the filter, and even when the filter member is blocked, the high pressure oil is filtered inside the piston by the differential pressure. It is configured to push in and bypass the oil, and the life of hydraulic pump and motor Chapter as well as relates to a filter built-in hydraulic pump and motor piston assembly so that the optimum lubricating conditioning.

Description

Piston Assemblies in Hydraulic Pump and Motor having a Filter therein

The present invention is used in swash plate type hydraulic pump and motor, by preventing the scratch of the static pressure bearing by foreign substances in the high-pressure oil flowing into, to extend the life of the hydraulic pump and motor and to create an optimum lubricating condition and a filter built-in hydraulic pump and It relates to a motor piston assembly.

Conventional swash plate hydraulic piston pump and motor 100, as shown in Figure 1, first look at the configuration, drive shaft 101, swash plate 102, shoe 103, piston 105, cylinder block 106 ), The valve plate 107 and the like,

The piston 105 has a cylindrical shape and the other side has a spherical shape, and the cylinder block 106 is where the piston 105 is inserted, and seven to eleven cylinder holes are machined on the same pitch circle at regular intervals.

The valve plate 107 is fixed to the pump rear casing, on which the cylinder block 106 rotates at high speed, the suction and discharge ports are designed, and the shoe 103 is connected to the piston and the sphere 104. Is rotated at a high speed on the fixed swash plate 102,

The swash plate 102 is inclined at a predetermined angle to the drive shaft 101, and the discharge flow rate of the piston pump is determined by the swash plate 102 angle. The drive shaft 101 is generally coupled to the center of the cylinder block 106 and the spool line in the swash plate type.

Looking at the operating principle of the swash plate piston pump, first, when the drive shaft 101 rotates, the cylinder block 106 connected to the drive shaft 101 is rotated. The rotation of the cylinder block 106 causes the piston 105 to rotate while contacting the inclined swash plate 102 surface through the shoe 103 connected by the spherical bearing and simultaneously reciprocate in the cylinder.

In the case of the swash plate piston motor, on the contrary, when the high pressure oil O entering the cylinder pushes the piston 105, the piston rotates while contacting the inclined swash plate 102 surface, and thus the cylinder block 106 rotates. It rotates together with the drive shaft 101. When the cylinder block 106 rotates once, the piston 105 performs the suction and discharge strokes one by one. That is, the suction stroke is made in the half-turn section in which the piston 105 exits from the inside of the cylinder, and the discharge stroke is made in the half-turn section in which the piston 105 moves toward the inside of the cylinder. This suction / discharge is repeated through the suction / discharge port designed in the valve plate 107. In the discharge stroke in the case of a pump and in the suction stroke in the case of a motor, the piston 105 is pushed to the swash plate 102 by hydraulic force, but in the opposite case, the piston shoe 103 is pushed through the spring in the cylinder block 106. Since the shoe 102 is pushed toward the swash plate 102, the shoe 102 always moves while touching the swash plate 102 surface.

Therefore, in order to achieve high efficiency of the pump and motor, it is necessary to improve the lubrication performance of the contact portion between the mutual components.

Furthermore, since the shoe 103 rotates while contacting the fixed swash plate 102 at a high speed, as shown in FIG. 2 and FIG. The hydrostatic bearing 107 and the swash plate are designed by designing a hydrostatic bearing 107 in the portion of the shoe 103 in contact with the swash plate 102 to guide discharge pressure thereto so that a constant pressure is formed on the hydrostatic bearing 107. The fluid of the high pressure oil flows through a gap of several microns (10 to 15 µm) formed between the 102 to prevent solid friction from occurring.

However, as the particles inside the high pressure oil, that is, foreign matters flow into the positive pressure bearing 107, scratches occur in the positive pressure bearing 107, which is caused by scratches caused by contaminated particles passing through the thin oil film. do.

If the static pressure bearing 107 is scratched, the static pressure bearing ratio (Bearing ratio) is changed to change the thickness of the oil film and the solid friction is gradually increased, the efficiency is reduced and the damage occurs.

Therefore, the development of the hydraulic pump and the motor piston assembly which can prevent the solid contact phenomenon of the shoe and the swash plate and ensure more reliable lubrication performance by the continuous high speed / high pressure of the swash plate hydraulic piston pump and the motor are urgently needed. It is a required situation.

The present invention has been made to solve the above problems, the object of the present invention is a piston assembly for use in swash plate hydraulic pump and motor, the static pressure bearing formed on the shoe of the piston assembly is scratched by foreign matter in the high pressure oil In order to prevent this from happening, a small precision filter is built in the piston to extend the life of the hydraulic pump and the motor, and to achieve high efficiency due to the formation of optimum lubrication conditions. To provide an assembly.

Other objects and advantages of the present invention will be described below, and will be appreciated by the embodiments of the present invention. Furthermore, the objects and advantages of the present invention can be realized by means and combinations indicated in the claims.

The present invention as a means for solving the above problems, the piston 10 and the high pressure oil is introduced into the longitudinal direction therein; A shoe 30 connected to one side of the piston 10 and having a positive pressure bearing 40 formed at the other side thereof so that a part of the high pressure oil of the piston flows into the positive pressure bearing 40 to perform a lubrication role; In order to prevent scratches from occurring in the positive pressure bearing 40 due to foreign matter in the high pressure oil, a change in the thickness of the oil film h with the swash plate 80 in contact with the shoe 30 may occur. A filter member 50 installed in the filter unit and filtering foreign substances of high pressure oil; A stop ring (60) installed at an inner circumference of the piston (10) to support one end of the filter member (50), thereby preventing the flow of the filter member (50) by the pressure of the high pressure oil; Characterized in that consists of.

In addition, the sphere 20 is integrally formed at one end of the shoe 30 so that the piston 10 and the sphere 20 are rotatably coupled, or the sphere 20 at one end of the piston 10. Forming integrally, characterized in that the sphere 20 and the shoe 30 is rotatably connected.

In addition, the filter member 50 is installed in the longitudinal direction inside the piston 10, it is characterized in that the elastic member 90 is coupled to the other end so as to be floating in the piston (10).

In addition, the filter member 50 has a cross section in the form of a straight line or has a cross section in the form of a hat (Hat) protruding to the inlet side of the high pressure oil.

In addition, a bypass means 70 having a check valve function is installed between the filter member 50 and the stop ring 60.

In addition, a plate spring is used as the bypass means 70 so that the other end of the filter member 50 is supported by the stepped protrusion 11 protruding on the inner circumference of the piston 10, but the filter member 50 is When clogged by foreign matter, the high pressure oil pressurizes the filter member 50 to compress the dish spring, and then the movement hole 71 formed in the flow path R and the dish spring formed on the outside of the filter member 50. Bypassed by (bypass), it is characterized in that to move to the positive pressure bearing 40 through the orifice 31 formed in the shoe (30).

As described above, the present invention has the effect of preventing the scratches of the static pressure bearing caused by the foreign matter by entering the positive pressure bearing to remove the internal foreign matter of the high pressure oil lubricating between the shoe and the swash plate. There is.

In addition, the present invention can prevent the problems such as the static pressure bearing ratio is changed by the scratch of the static pressure bearing, the thickness of the oil film is changed, the solid friction is so severe that the efficiency degradation and damage of the solid friction portion occurs. It works.

In addition, the present invention has the effect of maintaining the high efficiency by forming the optimum lubrication conditions, in addition to extending the life of the hydraulic pump and motor.

In addition, the present invention, even if the filter is installed in the piston to remove the foreign matter of the high pressure oil, the high pressure oil can be introduced into the positive pressure bearing side by bypassing the filter by the differential pressure, there is an effect that the problem does not occur in the lubrication action have.

1 is a cross-sectional view showing a conventional hydraulic pump and a motor.
Figure 2 is a cross-sectional view showing a conventional hydraulic pump and motor piston assembly.
3 is a cross sectional view of a first embodiment showing a piston assembly according to the present invention;
4 is a sectional view of a second embodiment showing a piston assembly according to the invention.
Figure 5 is a cross-sectional view of one embodiment showing the filter member of Figures 3, 4 according to the present invention in a different shape.
6 is a sectional view of a third embodiment showing a piston assembly according to the present invention;
Figure 7 is a hydraulic circuit diagram of one embodiment comparing the piston assembly of the prior art and the present invention in a hydraulic circuit.

Before describing the various embodiments of the present invention in detail, it will be appreciated that the application is not limited to the details of construction and arrangement of components described in the following detailed description or illustrated in the drawings. The invention can be implemented and carried out in other embodiments and can be carried out in various ways. In addition, device or element orientation (e.g., "front", "back", "up", "down", "top", "bottom" The expressions and predicates used herein with respect to terms such as ",""left","right","lateral", etc. are used merely to simplify the description of the present invention, and related apparatus. Or it will be appreciated that the element does not simply indicate or mean that it should have a particular direction.

The present invention has the following features to achieve the above object.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the present specification and claims should not be construed as being limited to the common or dictionary meanings, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.

Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalent water and variations.

Hereinafter, a filter-integrated hydraulic pump and a motor piston assembly according to a preferred embodiment of the present invention will be described in detail with reference to FIGS. 3 to 7.

As shown, the filter-integrated hydraulic pump and motor piston assembly according to the present invention is a piston 10, a shoe (30, Shoe), a filter member (50, Filter), a stop ring (60, Snap ring), bypass means ( 70) and an elastic member 90.

Description of the swash plate hydraulic pump and motor to which the filter-mounted hydraulic pump and the motor piston assembly according to the present invention are applied is described in detail with reference to the [Hydraulic Circuit 1] of FIGS. 1 and 2 and 7. Odd number of piston assemblies (generally nine are used) move forward and backward to generate discharge or rotational force of the flow rate.

The hydraulic pump receives mechanical power (torque and rotational speed) from an electric motor or engine such as an electric motor, and changes the fluid power (pressure and flow rate), while the hydraulic motor receives the fluid power to receive mechanical power. Will be converted.

The piston 10 has a circular tubular shape with an empty inside, so that the high pressure oil (O) can be introduced into the inside,

One end of the piston 10 is a spherical sphere-shaped sphere (20, Ball) is coupled, the sphere 20 is swaging (swaging) to enable rotation at the end of the piston (10).

The sphere 20 is welded to one side of the shoe 30 in contact with the swash plate 80 formed in the piston pump and the motor is fixed integrally, the shoe 30 in contact with the swash plate 80 The other side of the hydrostatic bearing (40, Hydrostatic Bearing) is formed to form a pressure pocket.

Thus, the piston 10 is forward and backward by the pressure of the high-pressure oil flowing into the piston 10 to generate the discharge or rotational force of the flow rate, in this case, the shoe 30 and the swash plate 80 made of metal ), Frictional heat is generated, and as the friction surface becomes rough, solid friction such as fast wear or sticking (sintering) is generated.

In order to prevent this, the sphere 20 penetrates the inlet hole 21 through which a portion of the high pressure oil introduced into the piston 10 is introduced, and the inlet hole 21 in the hydrostatic bearing 40. An orifice 31 is formed to communicate with each other, so that a small amount of the high pressure oil flows into the positive pressure bearing 40 through the inlet hole 21 and the orifice 31.

Thus, the trace amount or very small amount introduced into the positive pressure bearing 40 (the flow rate supplied to the positive pressure bearing 40 through the orifice 31 is about 0.96% of the total flow rate of the high pressure oil introduced into the piston 10). High pressure oil is lubricated while forming a thin oil film (h, Oil Film) between the shoe 30 and the swash plate 80, more specifically, the positive pressure bearing 40 and the swash plate 80. It is working.

As shown in the [hydraulic circuit 2] of FIGS. 3 to 5 and 7, the filter member 50 filters foreign substances in the high pressure oil flowing into the piston 10, and the positive pressure bearing 40. This is to prevent scratches in the positive pressure bearing 40 due to a small amount of foreign substances in the high pressure oil flowing therein.

To this end, the filter member 50 of the mesh form is placed inside the piston 10 into which the high pressure oil is introduced. The inner end of the piston 10 has a stepped portion 11 so that the other end of the filter member 50 is hung locally. ) To support the filter member 50 is not moved to the inlet side of the high pressure oil.

The stop ring 60 is for fixing the filter member 50 described above so as not to flow by the high pressure oil, to support one end of the filter member 50 having the other end supported on the step 11, It is fixed around the inner circumference of the piston (10). As a result, the filter member 50 is floated without moving in the direction of the shoe 30 by the high-pressure oil introduced therein.

That is, the filter member 50 is inserted into and fixed between the step 11 and the stop ring 60 in the piston 10. Thus, the filter member 50 embedded in the piston 10 is a piston. After removing the foreign matter in the high pressure oil introduced into (10), a small amount of the high pressure oil from which the foreign matter is removed is to be introduced into the positive pressure bearing 40 through the orifice 31.

As described above, as shown in FIGS. 3 and 4, the filter member 50 fitted to the step 11 and the stop ring 60 has a straight shape such as '│' and stops with the step 11. In the state located between the rings 60 or as shown in FIG. 5, between the step 11 and the stop ring 60, the central portion protrudes toward the inlet side of the high pressure oil in the piston 10. By being in the form of a hat (Hat) standing sideways, it is possible to increase the area of the filter member 50 to increase the filtration efficiency.

The bypass means 70, as shown in the [hydraulic circuit 3] of FIGS. 4 to 5 and 7, when the filter member 50 in the piston 10 described above is blocked by foreign matter, a small amount of high pressure It is to prevent oil from flowing into the static pressure bearing 40 so that the lubrication role is stopped, and is installed between the filter member 50 and the stop ring 60.

In the present invention, the bypass means 70 used a plate spring having a plurality of movable holes 71 perforated around the circumferential surface, which will be described in detail based on this, the filter member 50 is stepped around the other end While being supported by (11), one side of the dish spring is supported on one end side of the filter member 50, and the other side of the dish spring is to be supported corresponding to the stop ring (60).

In other words, when the filter member 50 performs the filtering role, the other end of the filter member 50 has a form supported by the step 11 by the tension force of the dish spring, so that the high pressure oil When the filter member 50 is blocked, the filter member 50 is pushed toward the stop ring 60 while the plate spring is compressed by the pressing force of the high pressure oil flowing therein. For this reason, the high pressure oil which flows in contact with the step 11, and the filter member 50 which spreads over and detours through the flow path spaced apart from the step 11, and the bypassed high pressure oil moves of the compacted spring. After passing through the ball 71 is to move to the positive pressure bearing 40 through the orifice 31. That is, the bypass means 70 is to act as a check valve that is operated only when the filter member 50 is clogged with foreign matter.

Of course, for this purpose, the filter member 50 is formed with a diameter smaller than the inner diameter of the other side of the piston 10 in which the filter member 50 is installed, and the filter member 50 having the other end circumferentially supported on the step 11. It will be obvious that a flow path through which the high pressure oil can be bypassed is formed.

In addition, the filter-embedded hydraulic pump and motor piston assembly of the present invention may be configured as shown in FIG. 6 according to an embodiment of the user.

3 and 4, the sphere 20 is integrally fixed to one side of the shoe 30 (ex: welding), so that one end of the piston 10 is swaged with the sphere 20. By doing so, the piston 10 and the sphere 20 is connected to be rotatable,

6, the sphere 20 is integrally fixed to one side of the piston 10 so that one side of the shoe 30 is swaged with the sphere 20. The sphere 20 and the shoe 30 are connected to be rotatable.

In the case of FIG. 6, the inlet hole 21 ′ is provided in the sphere 20 so that the high pressure flow flowing into the piston 10 may flow into the positive pressure bearing 40 formed on one surface of the shoe 30. This through-formed, it will be obvious that the communication hole 32 which is in communication with the inlet hole 21 ′ is formed in the shoe 30. (Of course, depending on the user's embodiment, the orifice may be formed inside the sphere 20 or the shoe 30 to flow a small amount of the high pressure oil flowing into the positive pressure bearing 40.)

In addition, the filter member 50 installed in the piston 10 is installed throughout the longitudinal direction in the piston 10, so that the filtration area is increased.

Such, the filter member 50 is to be supported by one end by a stop ring 60 is fixed to the inside of one side of the piston 10, as shown in Figure 3 or 4, step 11 in the piston 10 Without forming a), and the other end of the filter member 50 is coupled to the elastic member (spring, etc.) 90 and installed in the piston 10, the compressed and the elastic member 90 is installed in the piston (10) As the tension is restored to the original position inside, the other end of the filter member 50 is pressed toward the stop ring 60 by the return force of the elastic member 90, consequently the filter member 50 is the piston (10) To make it float inside.

As mentioned above, although this invention was demonstrated by the limited embodiment and drawing, this invention is not limited by this, The person of ordinary skill in the art to which this invention belongs, Various modifications and changes may be made without departing from the scope of the appended claims.

10: piece 11: step
20: old 21, 21 ': inlet hole
30: shoe 31: orifice
32: communication hole 40: hydrostatic bearing
50: filter member 60: stop ring
70: bypass 71: moving ball
80: swash plate 90: elastic member
h: oil film O: high pressure oil
R: Euro

Claims

A piston 10 into which the high pressure oil flows in the longitudinal direction;
A shoe 30 connected to one side of the piston 10 and having a positive pressure bearing 40 formed at the other side thereof so that a part of the high pressure oil of the piston flows into the positive pressure bearing 40 to perform a lubrication role;
In order to prevent scratches from occurring in the positive pressure bearing 40 due to foreign matter in the high pressure oil, a change in the thickness of the oil film h with the swash plate 80 in contact with the shoe 30 may occur. A filter member 50 installed in the filter unit and filtering foreign substances of high pressure oil;
And a stop ring 60 installed at an inner circumference of the piston 10 to support one end of the filter member 50 to prevent the flow of the filter member 50 due to the pressure of the high pressure oil.
The filter member 50 is installed in the longitudinal direction inside the piston 10, so that the floating in the piston (10), the built-in hydraulic pump, characterized in that the elastic member 90 is coupled to the other end is installed and Motor piston assembly.

A piston 10 into which the high pressure oil flows in the longitudinal direction;
A shoe 30 connected to one side of the piston 10 and having a positive pressure bearing 40 formed at the other side thereof so that a part of the high pressure oil of the piston flows into the positive pressure bearing 40 to perform a lubrication role;
In order to prevent scratches from occurring in the positive pressure bearing 40 due to foreign matter in the high pressure oil, a change in the thickness of the oil film h with the swash plate 80 in contact with the shoe 30 may occur. A filter member 50 installed in the filter unit and filtering foreign substances of high pressure oil;
The stop ring 60 is installed on the inner circumference of the piston 10 to support one end of the filter member 50 to prevent the flow of the filter member 50 due to the pressure of the high pressure oil.
The filter member 50 has a cross section in the form of a straight line or has a cross section in the form of a hat (Hat) in which the central portion protrudes toward the inlet side of the high pressure oil.
A filter-integrated hydraulic pump and motor piston assembly, characterized in that a bypass means (70) having a check valve function is installed between the filter member (50) and the stop ring (60).

3. The method according to claim 1 or 2,
The sphere 20 is integrally formed at one end of the shoe 30 so that the piston 10 and the sphere 20 are rotatably coupled or the sphere 20 is integrated at one end of the piston 10. It is formed by, so that the sphere (20) and the shoe (30) is rotatably connected, characterized in that the hydraulic pump and motor piston assembly with a filter.

The method of claim 2,
As the bypass means 70, a plate spring is used,
While the other end of the filter member 50 is supported on the stepped protrusion 11 protruding in the inner circumference of the piston 10,
If the filter member 50 is blocked by foreign matter,
The high pressure oil presses the filter member 50 to compress the dish spring, and then bypasses the flow path R formed at the outside of the filter member 50 and the moving hole 71 formed in the dish spring. ), Built-in hydraulic pump and motor piston assembly, characterized in that to move to the positive pressure bearing (40) through the orifice (31) formed in the shoe (30).

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