KR101867529B1 - Piston pump - Google Patents

Abstract

The present invention provides a piston pump for pumping hydraulic pressure to various kinds of equipment operated by hydraulic pressure. The piston pump includes: a housing (10); a shaft (20) rotatably coupled to the housing (10); a rear cover (30) including a suction hole (31) communicating with the inner space of the housing (10), and first and second discharge holes (32, 34), the rear cover (30) having a pilot hydraulic inlet groove (33PI) through which a pilot hydraulic pressure input from the suction hole (31) is input and a pilot hydraulic pressure drain groove (33PO) through which the pilot hydraulic pressure is discharged, the rear cover being coupled to a rear end of the housing (10); a barrel (40) having a plurality of piston holes radially arranged with respect to a central portion thereof and disposed in front of the rear cover (30) while being coupled to an outer peripheral surface of the shaft (20); a swash plate (50) housed in an inner space of the housing (10) to be disposed between a front end of the housing (10) and the barrel (40); a plurality of pistons (60) reciprocally coupled to the piston holes of the barrel (40); a shoe (70) coupled to the piston (60) and having a front end contacting the swash plate (50); and a rotor (80) coupled to the shaft (20) and rotatably coupled to the rear cover (30).

Description

Piston pump

The present invention relates to a piston pump for pumping hydraulic pressure for operating a heavy equipment such as an excavator, and a piston pump of a new construction capable of realizing a compact size while performing three pump functions.

A hydraulic transmission is used to shift the vehicle such as a combine or tractor. In general HST, a variable capacity piston pump and a fixed capacity piston motor are integrally formed, and the output of the motor is determined according to the swing angle of the swash plate of the variable displacement pump. Hydrostatic transmission (H.S.T: Hydrostatic transmission) is a continuously variable transmission that drives a hydraulic pump (variable displacement type) using an external power source and a hydraulic motor (fixed displacement type) through a hydraulic piping. The direction of the swash plate (swash plate) controls the direction and speed of the motor respectively by the angle.

The hydraulic oil pressure transmission is constituted such that the hydraulic oil discharged by the variable displacement piston pump driven by the engine is supplied to the hydraulic motor and then fed back to the piston pump. In order to simplify the formation of the hydraulic oil pipe, A piston pump is driven by an engine, and a hydraulic motor connected through a hydraulic pipe is driven.

A shoe plate is disposed on the piston pump in a face-to-face contact with a swash plate which is operated to swing by an operation lever (not shown), and the shoe plate is provided in a plurality of cylinders With the structure in which the piston assemblies are arranged, the cylinders are linked by the operation of the swash plate. The capacity of the swash plate type piston pump is changed by the reciprocating stroke of the piston when the swash plate makes one revolution and the reciprocating stroke of the piston is determined by the angle at which the front surface of the swash plate becomes the center of the shaft, do.

In other words, the piston pump includes a shaft rotatably coupled to the casing, a cylinder block splined to the shaft and having a plurality of piston chambers formed in parallel with the rotation axis around the rotation axis, and a piston block A swash plate, and a valve plate in contact with the cylinder block, and the cylinder block is pressed against the valve plate by a spring provided between the cylinder block and the rotating shaft, and is driven by a rotating shaft. As the cylinder block rotates, the piston reciprocates in a stroke regulated by the swing angle of the swash plate while revolving on the rotating shaft, and performs the pump action through the hydraulic inlet of the valve plate and the hydraulic outlet.

However, in the case of a conventional swash plate type hydraulic piston, a suction pump for suctioning hydraulic oil and a discharge pump for discharging hydraulic oil are required, and a pilot pump for operating a heavy equipment such as an excavator There is a problem that the structure of the pump system itself becomes complicated. In addition, in addition to a suction pump and a discharge pump, a conventional pilot pump must be installed separately. However, if the pilot pump is separately installed, the problem arises that the size of the pump must be increased. That is, there is a problem that the weight of the hydraulic portion is increased and the volume is increased.

Korean Registered Patent No. 10-1256871 (Registered on April 16, 2013) Korean Registered Patent No. 10-0936831 (Registered on January 1, 2010) Korean Registered Patent No. 10-1289308 (Registered on July 17, 2013)

SUMMARY OF THE INVENTION It is an object of the present invention to provide a piston pump for pumping hydraulic pressure to various equipment operated by hydraulic pressure including heavy equipment such as an excavator and a loader. It is a primary object of the present invention to provide a piston pump of a new construction capable of realizing a compact size while having three pump functions.

According to an aspect of the present invention, A shaft rotatably coupled to the housing; A first discharge hole and a second discharge hole communicated with an inner space of the housing, a pilot hydraulic inflow groove through which the pilot hydraulic pressure flowing in the suction hole enters, and a pilot hydraulic pressure inflow groove through which the pilot hydraulic pressure is discharged, A rear cover coupled to the rear end of the housing; A barrel having a plurality of piston holes in a radial direction with respect to a central portion thereof and being disposed on a front side of the rear cover coupled to an outer circumferential surface of the shaft; A swash plate housed in an inner space of the housing to be disposed between a front end of the housing and the barrel; A plurality of pistons reciprocally coupled to the piston holes of the barrel; A shoe coupled to the piston and having a front end contacting the swash plate; And a rotor coupled to the shaft and rotatably coupled to the rear cover.

An inner rotor coupled to the shaft, the inner rotor having a plurality of inner engagement protrusions therein; Wherein the inner rotor has one or more outer engaging projections as compared with the plurality of inner engaging projections of the inner rotor and the outer rotor is engaged with the inner engaging projections of the inner rotor, And an outer ground rotor for securing a pilot pumping chamber.

The piston pump according to the present invention is capable of compactly implementing the three pump functions while pumping the main hydraulic pressure to the P1 and P2 ports and simultaneously pumping the pilot hydraulic pressure to the P3 port and the weight of the hydraulic system itself is considerably reduced There is an effect that can be reduced.

It should be understood, however, that the above-described effects are the main effects of the present invention, and that the present invention has various desirable effects other than the above effects, and that the features of the present invention are not limited by the above effects something to do.

1 is an exploded perspective view of a piston pump according to the present invention;
Fig. 2 is a perspective view showing the rear side of the main part shown in Fig.
3 is a perspective view of a piston pump according to the present invention.
4 is a perspective view showing the rear side of the piston pump according to the present invention;
5 is a side sectional view showing the internal structure of the piston pump shown in Fig. 3
6 is a perspective view showing the inlet of the rear cover, which is a main part of the present invention.
7 is a perspective view showing the P1 port, the P2 port, and the P3 port of the rear cover shown in Fig.
8 is a perspective view showing a disassembled state of the rear cover and the valve plate,
Fig. 9 is a perspective view showing the combined state of the valve plate and the rear cover shown in Fig. 8
10 is a front view of Fig. 9
Fig. 11 is a perspective view showing an exploded state of the rotor and the rear cover,
Fig. 12 is a perspective view showing the combined state of the main rotor and the rear cover shown in Fig. 11; Fig.
Fig. 13 is a rear view showing the combined state of the main rotor and the rear cover shown in Fig. 12

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The objects, features and advantages of the present invention will be more readily understood by reference to the accompanying drawings and the following detailed description. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. For example, if a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected or connected to the other component, It is to be understood that other components may be "connected "," coupled "

Referring to the drawings, a piston pump according to the present invention includes a housing 10, a shaft 20 rotatably coupled to the housing 10, a rear cover 30 coupled to the housing 10, A barrel 40 disposed in the inner space of the housing 10 and disposed in front of the rear cover 30 and a barrel 40 disposed between the front end of the housing 10 and the barrel 40, A plurality of pistons 60 reciprocally coupled to the piston holes of the barrel 40; A shoe 70 coupled to the piston 60 and having a front end in contact with the swash plate 50 and a rotor 80 coupled to the shaft 20 and rotatably coupled to the rear cover 30, .

The housing 10 is formed in a cylindrical shape having a space portion therein. In the present invention, the housing 10 is formed in a cylindrical shape. A shaft engaging hole is provided at the center of the front end of the housing (10). The inner space of the housing 10 is opened to the rear end of the housing 10.

The rear cover 30 is coupled to the rear end of the housing 10. The rear cover 30 has a rectangular block shape having an inner surface and an outer surface, an upper surface and a bottom surface, and both side surfaces. The rear cover 30 is coupled to the rear end of the housing 10 by fasteners such as bolts.

The rear cover 30 includes a first discharge hole 32, a second discharge hole 34, a pilot hydraulic inlet hole 31, a pilot hydraulic inlet groove 33PI, a pilot hydraulic pressure discharge groove 33PO, And an outlet hole (38).

The suction hole (31) communicates with the inner space of the housing (10). The suction hole 31 is communicated from the suction port SP formed on one side surface of the rear cover 30 to the inner suction port on the inner surface of the rear cover 30 so that the suction hole 31 is communicated with the inside of the housing 10 And communicates with the space portion.

The first discharge hole (32) and the second discharge hole (34) communicate with the inner space portion of the housing (10). The first discharge hole 32 is communicated from the first port P1 formed on the other side surface portion of the rear cover 30 to the first inner discharge port on the inner surface of the rear cover 30, ) Communicates with the inner space portion of the housing (10). The second discharge hole 34 is communicated from the second port P2 formed on the other side surface portion of the rear cover 30 to the second inner discharge port on the inner surface of the rear cover 30, (34) also communicate with the inner space portion of the housing (10).

The pilot hydraulic inlet hole 31PI communicates with the suction hole 31 formed on one side of the rear cover 30 and also communicates with the rotor receiving groove 30G provided on the outer surface of the rear cover 30. [ And the pilot hydraulic inlet hole 31PI communicates with the inner peripheral surface of one side of the ground receiving groove 30G. The pilot hydraulic pressure is introduced through the pilot hydraulic inlet hole 31PI. The pilot hydraulic pressure is a part of the hydraulic pressure entering the suction hole 31 of the rear cover 30. [ That is, the hydraulic pressure entering the suction hole 31 of the rear cover 30 enters the suction hole 31 and the pilot hydraulic inlet hole 31PI, and a part of the hydraulic pressure entering the pilot hydraulic inlet hole 31PI It becomes pilot hydraulic.

The pilot oil pressure discharge groove 33PO is connected to a third port P3 formed on the other side of the rear cover 30. [ That is, the pilot hydraulic pressure supply groove 33PO communicates with the ground receiving groove 30G of the rear cover 30 and also communicates with the third port P3. The pilot hydraulic pressure supply groove 33PO is communicated with the other inner circumferential surface of the ground receiving groove 30G to reach the third port P3. The pilot hydraulic pressure introduced through the pilot hydraulic inlet hole 31PI is introduced into the pilot hydraulic pressure discharge groove 33PO by the rotor 80 to be described later and then is able to escape through the third port P3.

The shaft 20 is inserted into a shaft coupling hole at a front end portion of the housing 10 and a rear shaft coupling hole provided at a center portion of the rear cover 30 and is embedded in the inner space portion of the housing 10. The shaft 20 can be coupled to the shaft coupling hole of the housing 10 and the rear shaft coupling hole of the rear cover 30 via the bearings.

A barrel (40) is coupled to the outer circumferential surface of the shaft (20). The barrel (40) is disposed in front of the rear cover (30). That is, the barrel 40 is disposed in the inner space portion between the front end portion of the housing 10 and the inner surface of the rear cover 30, and the barrel 40 is disposed in front of the rear cover 30. The barrel 40 is formed in the shape of a block having a circular section. The barrel 40 is provided with a plurality of piston holes. A plurality of piston holes are provided in the radial direction with respect to the center of the barrel (40). A plurality of piston holes are provided at regular intervals along the circumferential direction with respect to the center of the barrel 40 as a reference. The piston hole communicates with the front end portion of the barrel 40 to the rear end portion.

A valve plate 110 is coupled to an inner surface of the rear cover 30 and a rear end of the barrel 40 is coupled to an inner surface of the valve plate 110. The shaft 20 is coupled to a rear shaft coupling hole of the rear cover 30 through a plate shaft hole formed in a center portion of the valve plate 110. The outer circumferential surface of the shaft 20 may be coupled to the plate shaft hole formed in the valve plate 110 via a bearing. The barrel 40 and the valve plate 110 are fixed to the rear cover 30 so that the shaft 20 rotates and the barrel 40 and the valve plate 110 are fixed.

The swash plate 50 is embedded in the inner space of the housing 10. The swash plate (50) is disposed between the front end of the housing (10) and the barrel (40). A shaft hole of a swash plate (50) formed at the center of the swash plate (50) is coupled to an outer peripheral surface of the shaft (20). And the swash plate 50 is configured to rotate together with the rotation of the shaft 20.

A piston (60) is coupled to each piston hole of the barrel (40). The piston (60) is inserted to reciprocate in the piston hole of the barrel (40). So that the piston (60) reciprocates forward and backward in the piston hole of the barrel (40).

The shoe 70 is coupled to the piston 60. The shoe 70 is engaged with the ball portion provided at the front end portion of the piston 60. The front end of the shoe is in contact with the swash plate 50. A setting panel 120 is interposed between the swash plate 50 and the front end of the piston 60. The setting panel 120 is provided with a number of shoe engagement holes corresponding to the number of the pistons 60, The shoe 70 is inserted into the engaging hole and at the same time is engaged with the tip of the piston 60. The tip of the piston (60) is a ball portion, and the shoe (70) is coupled to the ball portion of the piston (60). The tubular upper portion of the shoe 70 is engaged with the ball portion of the piston 60. And the ball portions of the shoe 70 and the piston 60 are combined in the form of a universal joint. In addition, the front surface of the shoe 70 is formed as a flat surface. Accordingly, the front surface of the shoe 70 is in surface-to-surface contact with the inner surface of the swash plate 50.

The ground rotor 80 is coupled to the shaft 20 and is rotatably coupled to the rear cover 30 at the same time. The rotor 80 includes an inner rotor 82 and an outer rotor 84.

The inner rotor 82 has a plurality of inner coupling protrusions 82P therein. A plurality of inner engaging projections 82P are radially arranged with respect to the center of the inner rotor 82. [ When seen from one side of the inner rotor 82, a plurality of inner engagement protrusions 82P are arranged at regular intervals in the form of a windmill. A center portion of the inner rotor (82) is coupled to the shaft (20).

The inner rotor (82) is coupled to the outer rotor (84). The outer rotor 84 has a plurality of outer coupling projections 84P therein. At this time, the number of the outer engagement protrusions 84P is one more than the inner engagement protrusions 82P. If the number of inner coupling protrusions 82P of the inner rotor 82 is N, the number of outer coupling protrusions 84P of the outer ground rotor 84 is N + 1. An engagement groove of the inner rotor 82 is secured between the respective outer joint engagement projections 84P. In the outer rotor 84, through-holes communicating on both sides are secured inside the plurality of outer coupling projections 84P. The inner rotor 82 is inserted into the through hole of the outer rotor 84 and a part of the inner engaging protrusions 82P of the inner rotor 82 is engaged with the outer rotor 82. [ Is engaged with the outer engaging protrusion 84P of a part of the engaging projection 84. [ A portion of the plurality of inner rotor 82 engaging grooves secured between the respective outer engaging projecting portions 84P of the outer rotor 84 includes a portion of the inner rotor 82 And is engaged with the groove 30G. The pilot pumping chamber 88 is ensured between the inner engaging protrusion 82P of the inner rotor 82 and the outer engaging protrusion 84P of the outer rotor 84. [ At this time, the pilot pumping chamber 88 is divided into a plurality of sector pilot pumping chambers 88 by a plurality of inner engaging protrusions 82P and an outer engaging protrusion 84P. When viewed from the front of the ground rotor 80 The area of the sector pilot pumping chamber 88 along the circumferential direction of the rotor 80 becomes larger and smaller. Clockwise direction as viewed from the outer side of the rotor 80 and proceeding from the first sector pilot pumping chamber 88 to the last sector pilot pumping chamber 88 and into each sector pilot pumping chamber 88, The cross sectional area of the sector pilot pumping chamber 88 is gradually reduced from the middle sector pumping chamber 88 to the middle. In other words, the cross-sectional area of the pilot pumping chamber 88 gradually increases along with the circumferential direction of the rotor 80, and then decreases gradually.

The inner rotor 82 has N coupling protrusions and the outer rotor 84 rotates with a rotation ratio of (N + 1) / N in a state having N + 1 coupling protrusions. Since the inner rotor and the outer rotor 84 have a constant eccentricity (eccentric rotation center), the eccentricity causes the volume that can carry the fluid fuel between the inner rotor 82 and the outer rotor 84 A portion S is formed. The volume portion refers to the pilot hydraulic chamber between the inner rotor 82 and the outer rotor 84. The portion where the volume of the rotor 80 is increased during the rotational motion sucks the fluid around by the pressure drop and the portion where the volume decreases decreases the pressure to discharge the fluid.

A valve plate 110 is disposed between the barrel 40 and the rear cover 30. The valve plate 110 is provided with a plate inner suction hole 31 and a plate discharge hole 114. [ The plate suction hole 112 and the plate discharge hole 114 penetrate to both sides of the valve plate 110. Plate suction holes 112 and plate discharge holes 114 are provided on both sides of the center of the valve plate 110 when viewed from one side of the valve plate 110. The plate suction hole 112 communicates with the suction hole 31 of the rear cover 30 and the plate discharge hole 114 communicates with the first discharge hole 32 formed in the rear cover 30, (34).

An inner suction port extending toward the suction hole 31 is provided on the inner surface of the rear cover 30. The inner suction port 30ISP is formed into a columnar hole shape when viewed from the inner surface of the rear cover 30. [ . The inner suction port is formed in the shape of a columnar hole erected in the vertical direction of the rear cover (30). The first discharge hole 32 and the second discharge hole 34 are communicated with the two inner suction ports 30ISP, respectively.

A plate suction hole 112 and a plate discharge hole 114 are provided on both sides of the central portion of the valve plate 110 when viewed from one side of the valve plate 110. The plate suction hole 112 is formed in a columnar hole shape when viewed from one side of the valve plate 110. The plate suction hole 112 is in the shape of a columnar hole erected in the vertical direction of the valve plate 110. That is, the plate suction hole 112 is formed in a columnar hole shape so as to meet the same area as the inner suction port formed on the inner surface of the rear cover 30. [

The valve plate 120 has two concentric circular plate grooves on the inner surface thereof and two plate discharge holes 114 in the plate concave groove region. The plate discharge hole 114 is composed of a first area plate discharge hole 114 and a second area plate discharge hole 114. The plate discharge hole 114 communicates with the outer surface of the valve plate 110 in the plate concave groove. The plate suction hole 112 meets the suction hole 31 of the rear cover 30 and the first area plate discharge hole 114 meets the first discharge hole 32 of the rear cover 30, The holes meet with the second discharge holes 34 of the rear cover 30. [ The main hydraulic pressure that has entered the suction hole 31 of the rear cover 30 enters the plate suction hole 112 of the valve plate 110 and passes through the plate discharge hole 114 of the valve plate 110, And the main oil pressure is discharged through the first port P1 and the second port P2 formed on the rear cover 30. The first port P1 and the second port P2 formed on the rear cover 30 are discharged through the first discharge hole 32 and the second discharge hole 34, .

Since the area of the plate suction hole 112 is larger than the area of the plate discharge hole 114, the amount of the main oil pressure that comes in the plate suction hole 112 per unit time is the main More than the amount of hydraulic pressure. That is, when the main hydraulic pressure is sucked, the main hydraulic pressure is quickly introduced into the suction hole 31, and when the main hydraulic pressure is discharged, the first and second discharge holes 32 and 34 are relatively slowly discharged.

The rear cover 30 is provided with a first inner port and a second inner port extending in the inner surface thereof toward the first discharge hole 32 and the second discharge hole 34, 2 inner port is formed into an elongated hole extending vertically when viewed from the inner surface of the rear cover 30. [ The first inner port meets the first area plate discharge hole 114 of the valve plate 110 and the second inner port meets the second area plate discharge hole 114 of the valve plate 110.

The rear cover 30 is formed with the suction holes 31 so as to communicate with one side from the inner side and the first discharge holes 32 and the second discharge holes 34 so as to communicate from the inner side to the other side. A suction port connected to the suction hole 31 is formed on the one side surface of the rear cover 30 and a first discharge hole 32 and a second discharge hole 32 are formed on the other side surface of the rear cover 30. [ (P1) and a second port (P2) are formed to be connected to the first port (34).

The rear cover 30 has a ground receiving groove 30G formed on an outer surface thereof opposite to an inner surface facing the inner space of the housing 10. The ground receiving groove 30G has a circular groove shape. The pilot oil pressure inlet groove 33PI and the pilot oil pressure outlet groove 33PO are communicated with the ground receiving groove 30G. A pilot oil pressure inlet groove 33PI and a pilot oil pressure outlet groove 33PO are provided on both sides of the center of the rotor receiving groove 30G when viewed from the outer surface of the rear cover 30. [ Of course, the pilot hydraulic inflow groove 33PI communicates with a part of the suction port formed on one side of the rear cover 30, and the pilot hydraulic pressure discharge groove 33PO is provided inside the other side of the rear cover 30 And communicates with the pilot hydraulic pressure discharge groove 33PO. The pilot hydraulic pressure discharge groove 33PO is communicated with the third port P3 provided on the other side face of the rear cover 30 so that the pilot hydraulic oil discharge groove 33PO is communicated with the pilot oil pressure discharge groove 33PO through the pilot hydraulic oil discharge groove 33PO. 3 port (P3). In other words, the pilot hydraulic oil inflow groove 33PI and the pilot hydraulic oil discharge groove 33PO are formed on both sides of the center of the ground receiving groove 30G of the rear cover 30 coupled to the rear end of the housing 10, And the pilot oil pressure inlet groove 33PI communicates with the suction hole 31 provided on one side of the rear cover 30 and the pilot oil pressure discharge groove 33PO communicates with the other side of the rear cover 30 And communicates with the third port P3 through the pilot hydraulic pressure supply groove 33PO provided on the side surface. The rotor accommodating groove 30G is provided with a pilot hydraulic inflow groove 33PI and a pilot hydraulic pressure let-off groove 33PO on both sides thereof with respect to a central portion thereof. The rotor accommodating groove 30G is rotatably coupled to the housing 10, The inner rotor 82 and the outer rotor 84 are rotatably coupled to the rotor accommodating groove 30G through a shaft 20 penetrating the rear shaft coupling hole of the inner rotor 82. [ And the pilot pumping chamber 88 is connected to the pilot hydraulic pressure supply groove 33PI and the pilot hydraulic pressure supply groove 33PO in accordance with the rotation of the shaft 20, the inner rotor 82 and the outer rotor 84, The area through which the pilot pumping chamber 88 of the rotor 80 communicates is varied. The fact that the area in which the pilot pumping chamber 88 of the ground rotor 80 opens the pilot hydraulic inflow groove 33PI and the pilot hydraulic pressure discharge groove 33P0 is variable means that the shaft 20 and the rotor 80 The area in which the pilot pumping chamber 88 of the rotor 80 communicates with the pilot hydraulic inlet groove 33PI gradually increases with the rotation of the rotor 80. The pilot pumping chamber 88 of the rotor 80 is connected to the pilot hydraulic- The area communicating with the pilot hydraulic pressure supply groove 33PO gradually decreases when the hydraulic oil is supplied to the region 33PO.

The pilot hydraulic inflow groove 33PI and the pilot hydraulic pressure discharge groove 33PO are formed in the shape of a circumferential groove extending from the upper portion to the lower portion when viewed from the front of the ground receiving groove 30G. At this time, the pilot hydraulic inflow groove 33PI and the pilot hydraulic pressure discharge groove 33PO are structured such that the width between the right and left ends is gradually increased from the lower portion toward the upper portion when the ground receiving groove 30G is viewed from the front. In other words, the lateral width of the ground receiving groove 30G is gradually reduced from the upper surface to the lower surface of the rear cover 30, as the pilot oil hydraulic inlet groove 33PI and the pilot hydraulic oil drain groove 33PO gradually decrease.

The operation of the piston pump according to the present invention will now be described.

In the piston pump of the present invention, the suction side piston (60) and the discharge side piston (60) are pumped while reciprocating (forward and backward movement). A plurality of pistons 60 on the right side relative to the center of the rear cover 30 are positioned on the discharge side pistons 60 of the remaining plurality of pistons 60 on the left side of the rear cover 30, The suction side piston 60 and the discharge side piston 60 perform pumping while repeating reciprocating movement in accordance with the rotation of the shaft 20 and the swash plate 50. The hydraulic pressure sucked through the suction hole 31 provided on one side of the rear cover 30 passes through the plate inner suction hole 31 of the valve plate 110 and is transmitted to the housing 10, And passes through the first discharge hole 32 and the second discharge hole 34 of the rear cover 30 through the plate discharge hole 114 of the valve plate 110 to be separated from the rear cover 30, To the first port (P1) and the second port (P2) provided on the other side surface.

At the same time, a part of hydraulic pressure in the hydraulic pressure entering through the suction hole 31 of the rear cover 30 also enters the pilot suction hole 31 of the rear cover 30 and enters the pilot hydraulic inlet groove 33PI. The pilot hydraulic inflow groove 33PI and the pilot hydraulic pressure discharge groove 33PO communicate with the pilot pumping chamber 88 between the inner rotor 82 and the outer rotor 84 in accordance with the rotation of the rotor 80 The pilot hydraulic pressure introduced into the pilot hydraulic inlet hole 36 of the rear cover 30 is received in the pilot hydraulic inlet groove 33PI and is transferred to the pilot hydraulic chamber as the guide. The pilot hydraulic pressure is transmitted to the pilot hydraulic pressure discharge groove 33PO of the rear cover 30 and then transmitted to the pilot hydraulic pressure discharge hole 38 of the rear cover 30 to be transferred to the side surface of the rear cover 30 And is discharged to the third port P3 formed. The hydraulic pressure introduced into the suction hole 31 of the rear cover 30 and the platen inner suction hole 31 of the valve plate 110 may be referred to as the main hydraulic pressure and the pilot hydraulic inflow hole 31 of the rear cover 30, The hydraulic pressure of a part of the hydraulic fluid entering the hydraulic pump 36 is referred to as a pilot hydraulic pressure.

In the present invention, the main rotor 80 transmits a pilot signal. The pilot signal means a pilot hydraulic pressure, and the pilot hydraulic pressure means a relatively low pressure and a low flow rate hydraulic pressure which is lower than the main hydraulic pressure. The main hydraulic pressure is the hydraulic pressure sent to the P1 port and the P2 port, and the pilot hydraulic pressure is the hydraulic pressure sent to the P3 port.

A plurality of pistons 60 inside the housing 10 are reciprocated by the rotation of the swash plate 50 so that the suction holes 31 of the rear cover 30 and the plate inner suction holes The pilot hydraulic pressure is introduced into the pilot hydraulic inlet hole 36 of the rear cover 30 and the main hydraulic pressure is transmitted to the plate inner and outlet holes of the valve plate 110 and the rear cover 30 And the pilot oil pressure is discharged to the first port P1 and the second port P2 through the first discharge hole 32 and the second discharge hole 34 in the pilot pumping chamber (P3) formed on the other side surface of the rear cover (30) through the pilot hydraulic oil outlet hole (38) of the rear cover (30) . That is, in the present invention, the geared rotor 80 receives the pilot hydraulic pressure in the hydraulic pressure entering the suction hole 31 of the rear cover 30 except for the main hydraulic pressure from the suction side and delivers the pilot hydraulic pressure to the discharge side. The suction side means the pilot hydraulic inflow hole 36 of the rear cover 30 and the discharge side means the pilot hydraulic inflow hole 38 of the rear cover 30. [

In the present invention, the ge 80 includes an inner rotor 82 coupled to the shaft 20 and an outer rotor 84. The two inner rotor 82 and the outer rotor 84 ) Is eccentric with a predetermined clearance so that the fluid is moved.

The inner rotor 82 and the outer rotor 84 are designed to have different rotational centers from each other and each of the inner rotor 82 and the outer rotor 84 is coupled to each other in any case, A number of sealed pilot pumping chambers 88 are formed to pump the pilot hydraulic pressure from the suction side to the discharge side. At this time, the inner rotor 82 and the outer rotor 84 rotate along their rotation center, and the pilot pumping chamber 88 becomes larger along the rotation direction on the suction side, and the pilot pumping chamber becomes smaller again on the discharge side The flow rate is balanced at a uniform flow rate.

In the present invention, the main rotor 80 transmits a pilot signal. The pilot signal means a pilot hydraulic pressure, and the pilot hydraulic pressure means a relatively low pressure and a low flow rate hydraulic pressure which is lower than the main hydraulic pressure. The main hydraulic pressure is the hydraulic pressure sent to the P1 port and the P2 port, and the pilot hydraulic pressure is the hydraulic pressure sent to the P3 port.

Therefore, the piston pump according to the present invention has the effect of realizing compactness of the three pump functions while pumping the main hydraulic pressure to the P1 and P2 ports and simultaneously pumping the pilot hydraulic pressure to the P3 port. In the past, hydraulic suction was carried out in two places. That is, in order to send the main hydraulic pressure to the main ports P1 and P2, the two pumps are pumped. On the other hand, the present invention advances hydraulic suction in one place. That is, the main hydraulic pressure can be sucked through one suction hole 31 of the rear cover 30 and pumped to the P1 port and the P2 port. Therefore, the piston pump according to the present invention has an effect of significantly reducing the size. In other words, in the case of the present invention, the hydraulic pressure is pumped to both the P1 port, the P2 port and the P3 port by one shaft 20 (precisely, the main hydraulic pressure and the pilot hydraulic pressure are pumped) The volume is also considerably reduced.

The pilot hydraulic oil inflow groove 33PI and the pilot hydraulic oil discharge groove 33PO formed in the lower rotor accommodating groove 30G of the rear cover 30 are formed so that when the lower rotor accommodating groove 30G is viewed from the front, So that the suction pressure load due to the suction pressure of the pilot hydraulic pressure coming into the pilot hydraulic inlet hole 36 of the rear cover 30 is reduced, Even when the pilot oil pressure is transmitted to the pilot oil pressure outlet hole 38 of the rear cover 30 by the rotation of the pilot oil pressure sensor 80, the discharge pressure load due to the pilot oil pressure discharge pressure can be compensated. That is, as the pilot hydraulic inflow grooves 33PI and the pilot hydraulic pressure outflow grooves 33PO gradually increase in width from left to right, the suction pressure of the pilot hydraulic pressure and the load pressure due to the pilot pressure of the pilot hydraulic pressure are attenuated The load resistance due to the inflow and outflow of the pilot hydraulic pressure is minimized and the transmission of the pilot hydraulic pressure is performed more smoothly.

The area of the plate suction hole 112 in the valve plate 110 is larger than the cross sectional area of the plate discharge hole 114 so that the main hydraulic pressure is rapidly introduced from the suction side and the discharge pressure is further increased at the discharge side, The main hydraulic pressure can be more smoothly pumped to the main load connected to the P2 port.

The specific embodiments of the present invention have been described above. It is to be understood, however, that the scope and spirit of the present invention is not limited to these specific embodiments, and that various modifications and changes may be made without departing from the spirit of the present invention. If you have, you will understand.

Therefore, it should be understood that the above-described embodiments are provided so that those skilled in the art can fully understand the scope of the present invention. Therefore, it should be understood that the embodiments are to be considered in all respects as illustrative and not restrictive, The invention is only defined by the scope of the claims.

10. Housing 20. Shaft
30. Rear cover 40. Barrel
50. Swash plate 60. Piston
70. Shu 80. Giroter
82. Inner rotor 84. Outer rotor

Claims (12)

A housing (10);
A shaft (20) rotatably coupled to the housing (10);
A suction hole 31 and a first discharge hole 32 and a second discharge hole 34 communicating with the inner space of the housing 10 are provided and the pilot oil pressure flowing into the suction hole 31 A rear cover (30) having a pilot hydraulic inlet hole (36) and a pilot hydraulic outlet hole (38) through which the pilot oil pressure is discharged, and which is coupled to the rear end of the housing (10);
A barrel (40) having a plurality of piston holes in a radial direction with respect to a central portion thereof and disposed in front of the rear cover (30) coupled to an outer circumferential surface of the shaft (20);
A swash plate 50 housed in the inner space of the housing 10 to be disposed between the front end of the housing 10 and the barrel 40;
A plurality of pistons (60) reciprocally coupled to the piston holes of the barrel (40);
A shoe 70 coupled to the piston 60 and having a front end contacting the swash plate 50;
And a rotor (80) coupled to the shaft (20) and rotatably coupled to the rear cover (30)
The ground rotor (80)
An inner rotor (82) having a plurality of inner engaging projections (82P) therein and coupled to the shaft (20);
The inner rotor 82 has one more outer engaging protrusion 84P than the plurality of inner engaging protrusions 82P of the inner rotor 82 and is coupled with the inner engaging protrusion 82P of the inner rotor 82 And an outer rotor 84 for securing a pilot pumping chamber 88 between the inner coupling protrusion 82P and the outer coupling protrusion 84P.
The method according to claim 1,
A valve plate 110 is disposed between the barrel 40 and the rear cover 30 and a plate suction hole 112 and a plate discharge hole 114 are formed in the valve plate 110 , The plate suction hole 112 communicates with the suction hole 31 of the rear cover 30 and the plate discharge hole 114 communicates with the first discharge hole 32 and the second discharge hole 34 ) Of the piston (1).
3. The method of claim 2,
Wherein an area of the plate suction hole (112) of the valve plate (110) is larger than a sectional area of the plate discharge hole (114).
The method of claim 3,
Wherein the plate suction hole (112) has a columnar hole shape when viewed from one side of the valve plate (110).
The method according to claim 1,
The rear cover 30 is formed with the suction holes 31 so as to communicate with one side surface from the inner side and the first discharge holes 32 and the second discharge holes 34 so as to communicate from the inner side to the other side. Is formed.
The method according to claim 1,
The rear cover 30 is formed with a ground receiving groove 30G formed on the outer surface opposite to the inner surface facing the inner space of the housing 10 and the pilot receiving groove 30G, And the inlet groove (33PI) and the pilot hydraulic pressure discharge groove (33PO) communicate with each other.
The method according to claim 6,
The pilot hydraulic oil inflow groove 33PI and the pilot hydraulic oil discharge groove 33PO are provided on both sides of the center of the ground receiving groove 30G of the rear cover 30 coupled to the rear end of the housing 10, The pilot hydraulic oil inflow groove 33PI communicates with the suction hole 31 provided on one side of the rear cover 30 and the pilot hydraulic oil discharge groove 33PO communicates with the other of the rear cover 30 And the third port (P3) provided on the side surface of the piston.
The method according to claim 6,
The ground receiving groove 30G is provided with a pilot hydraulic inlet groove 33PI and a pilot hydraulic outlet groove 33PO on both sides thereof with respect to a center portion thereof and is rotatably coupled to the housing 10, 30, a rear rotor 80 is coupled to the shaft 20 through the rear shaft coupling hole,
The ground rotor (80)
An inner rotor (82) having a plurality of inner engaging projections (82P) therein and coupled to the shaft (20);
The inner rotor 82 has one more outer engaging protrusion 84P than the plurality of inner engaging protrusions 82P of the inner rotor 82 and is coupled with the inner engaging protrusion 82P of the inner rotor 82 And an outer rotor 84 for securing a pilot pumping chamber 88 between the inner coupling protrusion 82P and the outer coupling protrusion 84P,
The inner rotor 82 and the outer rotor 84 are rotatably coupled to the ground receiving grooves 30G so that the pilot pumping chamber 88 is rotatably supported by the shaft 20 and the inner rotor Wherein the area communicating with the pilot hydraulic inflow groove (33PI) and the pilot hydraulic pressure supply groove (33PO) is variable according to the rotation of the outer rotor (82) and the outer rotor (84).
9. The method of claim 8,
Wherein the pilot hydraulic inlet groove 33PI and the pilot hydraulic pressure drain groove 33PO are in the form of a circumferential groove extending from the top to the bottom when viewed from the front side of the ground receiving groove 30G.
10. The method of claim 9,
The pilot hydraulic pressure inlet groove 33PI and the pilot hydraulic pressure outlet groove 33PO are formed such that the width between the right and left ends is gradually increased from the lower portion to the upper portion when viewed from the front of the ground receiving groove 30G Piston pump.
The method according to claim 1,
A setting panel 120 is interposed between the swash plate 50 and the distal end of the piston 60. The setting panel 120 is provided with a number of shoe engagement holes corresponding to the number of the pistons 60, Wherein the shoe (70) is inserted into the shoe coupling hole and is coupled to the tip end of the piston (60).
12. The method of claim 11,
The shoe 70 is coupled to the ball portion of the piston 60 so that the shoe 70 and the ball portion of the piston 60 are in the form of a universal joint Wherein the front surface of the shoe (70) is formed as a flat surface, and the front surface of the shoe (70) is in surface contact with the inner surface of the swash plate (50).

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