DE102008018035A1 - High efficiency radial piston pump, includes grooves carrying pressurized oil to form load-relieving hydrostatic sleeve bearing between moving parts - Google Patents

Abstract

The two pump components (10, 30) rotate relatively about an axis, sliding together at the coaxial contact surface (50). In the bores (38), pistons (32) move radially. A third component (41) is eccentric to one of the others (10, 30) and is led by the pistons of the second part (30). Feed and return channels (12, 16) for a compressed fluid have radial openings (14, 18). These communicate periodically with radial bores (38) of the second component (30). The novel feature is provision of load-relieving grooves (20, 22). The grooves are axially displaced to either side of the openings. They run around the contact surfaces of the first and second components.

Description

The invention relates to a radial piston pump having a first part, a second part which is rotatable relative to the first part about an axis, that the first and the second part in relative rotation on a coaxial to the axis contact surface slide together, and the more , in radially bores radially movable working piston, and a third part which is arranged eccentrically to the first or second part and from which the working piston of the second part are guided, wherein in the first part at least one supply and at least one discharge channel for a pressure medium Radial outputs are provided which communicate with relative movement of the first and second part periodically with the radial bores of the second part. A radial piston pump with the features of the preamble is off DD 257 103 A1 known.

In radial piston pumps working piston are arranged radially, wherein the lifting movement of a working piston is caused by an eccentric arranged on a pump shaft or an outer eccentric. At the DD 257 103 A1 known radial piston pump, a cylinder body is arranged coaxially with a hollow shaft, in which there are supply and discharge channels for a pressure medium. The feed channels are connected to the suction side and the discharge channels to the pressure side of the pump. In the cylinder body, the working piston are arranged radially, which are supported on an eccentrically arranged to the axis of the hollow shaft cam ring, which surrounds the cylinder body and the hollow shaft. In relative rotational movement between the hollow shaft and the cylinder body about the common axis on the one hand and relative eccentric loading movement of the cylinder body and the cam ring on the other hand, there is the lifting movement of the individual working piston, suck in this way pressure medium through the feed channels of the hollow shaft and eject through the discharge channels.

At the in DD 257 103 A1 described radial piston pump, the outputs of the supply and discharge channels for the pressure medium are particularly dimensioned to reduce the wear between the shaft and the cylinder body, when they rotate relative to each other.

task The present invention is a simple and inexpensive To specify solution with which reduces the wear is.

These Task is with a radial piston pump with the features of the claim 1 solved. Advantageous embodiments are Subject of dependent claims.

According to the invention in particular at least one relief groove provided at the Contact surface of the first and the second part axially offset from the radial bores of the second part and the radial outputs of the supply and discharge channels of the first part is provided and extends along the circumference of Contact surface of the first and the second part extends.

By such a relief groove can pressure oil from the pressure side get to the suction side of the pump, which at the contact surface between created a hydrostatic sliding bearing the first and the second part becomes. Direct contact between the first and the second part is prevented, and the friction is reduced at this point. Especially when approaching against pressure reduces the pump torque and a larger delivery volume and improved Positioning times are possible.

All in all improves the mechanical efficiency and thus the safe Function of the pump.

in principle can already have a positive effect with a single relief groove be achieved, the axially against the radial outputs the supply and discharge channels and the radial bores is offset. However, it is particularly advantageous if two relief grooves are provided, which are in axial Direction on different sides of the radial holes of the second part or different sides of the radial outputs the supply and discharge channels of the first Partly located. In this way, on both sides of the radial bores and the supply and discharge channels hydrostatic plain bearings.

at an advantageous development, the at least one relief groove an axial distance from the radial bores or the radial outputs the supply and discharge channels, about the axial extent of the radial outlets of the feed and discharge channels corresponds.

The inventive relief grooves can used with different designed radial piston pumps come.

Particularly advantageous is the use of a radial piston pump, wherein the first part comprises a pin and the second part comprises a relative to this pin about this rotatable piston body. In the piston body a plurality of radial bores radially movable working piston are provided. In this advantageous embodiment, the third part comprises an eccentrically arranged to pin stroke ring from which the Ar beitskolben be performed or in which support the working piston. Feed and discharge channels for a pressure medium are provided in the spigot, the radial outlets of the channels communicating periodically with the radial bores of the piston body during relative movement of the spool body and the spigot to perform the pumping function. In this embodiment, the at least one relief groove is provided on the contact surface of the piston body and the peg either axially offset in the inside of the piston body against its radial bores or in the outer side of the pin against the radial outlets of the supply and discharge channels and extends along the circumference of the contact surface of the piston body and the pin.

at the cam can be z. B. a ball bearing with a fixed Outer ring and one over balls stored therein Inner ring to guide the working piston act.

The Invention will be explained in detail with reference to the attached figures, the example of an embodiment of an inventive Represent radial piston pump. Showing:

1 a lateral cross section of a radial piston pump according to the invention and

2 a detailed view of the pin of the embodiment of the 1 ,

The cylindrical pin 10 includes a feed channel 12 with a radial outlet 14 in its lateral surface. Also, in the journal 10 a discharge channel 16 with a radial outlet 18 provided in the lateral surface of the pin. The channels are used for supplying or discharging pressure medium, for. B. pressure oil. To the pin 10 is a designed here as a cylinder body piston body 30 rotatably disposed, wherein the cylinder body 30 and the outside of the pin 10 at a contact surface 50 glide together. At least the cylinder body 30 and the pin 10 consist in this embodiment of metal. In the cylinder body 30 There are radial cylinder bores 38 in which working pistons 32 are radially movable. The radial movement of the working piston 32 in the radial bores 38 enlarges or reduces the respective working space 34 , With relative rotation of the cylinder body 30 and the pin 10 come the workrooms 34 periodically with the radial outputs 14 . 18 the supply and discharge channels 12 . 16 in connection.

The working pistons 32 are supported by support shoes 36 on a lifting ring 41 off, the eccentric to the pin 10 or the cylinder body 30 is arranged. In the embodiment shown, the lifting ring comprises 41 a fixed outer ring 42 in which the inner ring 40 over balls 44 is rotatably mounted in the manner of a ball bearing. Through the mating ring 43 become the Abstützschuhe 36 held in such a way that it makes contact with the inner ring 40 do not lose even though they are swiveling at it.

At the interface 50 between the cylinder body 30 and the pin 10 are two circumferential relief grooves 20 . 22 provided at a distance A ( 2 ) axially offset to the radial outputs 14 . 18 of the feed channel 12 or the discharge channel 16 in the cone 10 are provided. The distance A of the relief grooves 20 . 22 from the radial outputs 14 . 18 corresponds approximately to the axial extent B of the radial outputs 14 . 18 ,

The radial pump according to the invention of this embodiment is used as follows. The cylinder body 30 and thus the Abstützschuhe 36 the working piston 32 rotate together with the inner ring 40 of the ball bearing 41 , Because of the cylinder body 30 and the lifting ring 41 Are arranged eccentrically to each other, there is a radial movement of the working piston 32 , which causes the work space 34 the individual piston periodically increased or decreased. Pressure medium is in this way from the feed channel 12 (from the suction side of the pump) into the discharge channel 16 (to the pressure side of the pump) transferred.

During the rotation of the cylinder body 30 around the cone 10 it comes to friction at the contact surface 50 , Due to the higher pressure on the pressure side 16 Pressure oil enters the space between the cylinder body 30 and the outside of the pin 10 and can through the relief grooves 20 . 22 drain in the direction of the suction side. In this way creates a hydrostatic sliding bearing between the cylinder body 30 and the pin 10 , whereby the friction is minimized at this point and a direct metallic contact between pins 10 and cylinder body 30 is prevented.

Out The reduced friction results in a reduced pump torque. This is in particular a safe start against pressure and a larger delivery volume of the pump possible.

In the example described, the cylinder body rotates 30 around the fixed pin 10 , In an analogous manner, the invention z. B. also used in a radial piston pump, in which the control pin 10 rotates about an eccentric axis in the manner of an eccentric shaft and the working piston, which are supported in the eccentrically arranged lifting ring, not rotate.

The channels 12 . 16 are for the purposes of this description as feed or discharge channels be wrote. Their function can also be reversed if the direction of rotation of the pump is reversed accordingly. In particular, the pump can also be designed as a pump that pumps in both directions.

10

spigot

12

feed

14

radial Output of the feed channel

16

discharge channel

18

radial Output of the discharge channel

20

relief

22

relief

30

cylinder body

32

working piston

34

working space

36

support shoe

38

radial drilling

40

inner ring

41

lifting ring

42

outer ring

43

counter ring

44

Bullet

50

Touchpad

A

axial distance

B

axial Expansion of the radial outputs

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DD 257103 A1 [0001, 0002, 0003]

Claims (5)

Radial piston pump with a first part ( 10 ), a second part ( 30 ) which is rotatable relative to the first part about an axis, that the first and the second part in the relative rotation on a coaxial to the axis of the contact surface ( 50 ), and several, in radial bores ( 38 ) radially movable working pistons ( 32 ), and a third part ( 41 ), which is arranged eccentrically to the first or second part and from which the working piston ( 32 ) of the second part ( 30 ), wherein in the first part at least one supply and at least one discharge channel ( 12 . 16 ) for a printing medium with radial outlets ( 14 . 18 ) are provided, which in relative movement of the first and the second part periodically with the radial bores ( 38 ) of the second part ( 30 ), characterized by at least one relief groove ( 20 . 22 ) at the interface ( 50 ) of the first ( 10 ) and the second ( 30 ) Partially offset axially to the radial bores ( 38 ) of the second part or the radial outputs ( 14 . 18 ) of the supply and discharge channels ( 12 . 16 ) of the first part ( 10 ) is arranged along the circumference of the contact surface ( 50 ) of the first ( 10 ) and the second ( 30 ) Partly extends. Radial piston pump according to claim 1, characterized in that two relief grooves ( 20 . 22 ) are provided, which extend in the axial direction on different sides of the radial bores ( 38 ) of the second part ( 30 ) or on different sides of the radial outputs ( 14 . 18 ) of the supply and discharge channels ( 12 . 16 ) of the first part ( 10 ) are located. Radial piston pump according to one of claims 1 or 2, characterized in that the at least one relief groove ( 20 . 22 ) an axial distance (A) from the radial bores ( 38 ) or the radial outputs ( 14 . 18 ) of the supply and discharge channels ( 12 . 16 ), which is approximately the axial extent (B) of the radial outputs ( 14 . 18 ) of the supply and discharge channels ( 12 . 16 ) corresponds. Radial piston pump according to one of claims 1 to 3, characterized in that - the first part of a pin ( 10 ), - the second part a relative to the pin ( 10 ) about this rotatable piston body ( 30 ) with several in radial bores ( 38 ) of the piston body radially movable working piston ( 32 ), and - the third part is an eccentric to the pin ( 10 ) arranged cam ring ( 41 ), from which the working pistons are guided, - wherein in the pin ( 10 ) at least one supply and at least one discharge channel ( 12 . 16 ) are provided for a pressure medium whose radial outlets ( 14 . 18 ) with relative movement of the piston body ( 30 ) and the pin ( 10 ) periodically with the radial bores ( 38 ) communicate the piston body, and - the at least one relief groove ( 20 . 22 ) at the interface ( 50 ) of the piston body ( 30 ) and the pin ( 10 ) either in the inside of the piston body axially offset from the radial bores ( 38 ) or in the outside of the pin ( 10 ) axially offset to the radial outputs ( 14 . 18 ) of the supply and discharge channels ( 12 . 16 ) is provided and along the circumference of the contact surface ( 50 ) extends the piston body and the pin. Radial piston pump according to claim 4, characterized in that the lifting ring ( 41 ) a ball bearing with a fixed outer ring ( 42 ) and one about balls ( 44 ) mounted therein inner ring ( 40 ) for guiding the working pistons ( 32 ).