DE102021205558A1 - Hydraulic machine with feed and main pump and flexible tank connections - Google Patents

Abstract

The invention relates to a hydraulic machine comprising a main pump and a feed pump (20) which have a common first axis of rotation (11) and are accommodated in a common housing, the housing comprising a one-piece connection part (40), the connection part (40 ) has a peripheral surface (41) with respect to the first axis of rotation (11), wherein at least one tank connection (42; 43; 44) is arranged on the peripheral surface (41) and is permanently connected to a tank space (13) within the housing, wherein the tank space (13) is delimited at least in sections by the connection part (40), with a first and a second working connection being arranged on the peripheral surface (41), with the feed pump (20) having an inner part (21) which can be rotated with respect to the first axis of rotation (11) which is surrounded by an annular outer part (22), with a suction side of the feed pump (20) being permanently connected to the tank space (13). According to the invention, the tank space runs around (13) in the form of a closed ring around the outside of the outer part (22) of the feed pump (20).

Description

The invention relates to a hydraulic machine according to the preamble of claim 1.

From the DE 10 2007 011 644 B4 a hydraulic machine is known which comprises a main pump and a feed pump. The main pump is designed as an axial piston pump with a swash plate design. The feed pump can be designed as an internal gear pump, with vane pumps also being able to be used depending on the specific application. In both cases the feed pump has an inner part which is surrounded by an annular outer part. The hydraulic machine has a connection part in which a tank space is arranged, which opens out into a tank connection on the outside of the connection part. The feed pump sucks in pressurized fluid from the tank connection.

Hydraulic machines of this type are often used in mobile working machines, for example in hydraulic excavators. It should be possible to use one and the same type of hydraulic machine in a wide variety of working machines from different manufacturers. In a mobile work machine, there is little installation space for the hydraulic machine. It is therefore desirable if the hydraulic lines can be routed in the form of pipes over the shortest possible route within the mobile working machine. It is therefore advantageous if the connections of the connections of the hydraulic machine to be piped can be arranged at as many different points as possible, with as few parts of the hydraulic machine as possible having to be adapted for this purpose, with the cast blanks in particular being able to be used unchanged for all variants.

An advantage of the invention is that this objective is achieved for the tank port from which the feed pump draws pressurized fluid.

According to claim 1 it is proposed that the tank space runs in the form of a closed ring around the outside of the outer part of the feed pump. The main pump is preferably designed as an axial piston pump with a swash plate design, it most preferably having a continuously adjustable displacement volume. The displacement volume can preferably be adjusted beyond the zero displacement volume. A separate control or distribution plate of the main pump is preferably in direct contact with the connection part, in particular with a pump sealing surface. The hydraulic machine is preferably used in a closed hydraulic circuit, which is connected to the first and the second working port. A rotational movement of the main pump is preferably accompanied by an exchange of pressure fluid between the first and the second working connection, provided that a displacement volume of the main pump that is different from zero is set. The pressurized fluid is preferably a liquid, most preferably hydraulic oil.

A cast blank of the connection part is preferably designed in such a way that a tank connection can be drilled at a number of different locations, with each of these tank connections being permanently connected to the tank space. It is conceivable that all possible tank connections are drilled, with the tank connections that are not used being sealed in a fluid-tight manner with a separate cover or with a separate screw plug. However, it is also conceivable that only the tank connection that is actually used is drilled. The ring-shaped tank space according to the invention has the advantage that the tank connections can be arranged on one and the same cast blank at a wide variety of points on the peripheral surface. The feed pump is preferably designed as an internal gear pump, although it can also be designed as a vane pump. It preferably has a constant displacement volume.

Advantageous developments and improvements of the invention are specified in the dependent claims.

Provision can be made for the connection part to have an extension pointing in the direction of the first axis of rotation, with at least two control kidneys of the feed pump being arranged on an end face of the extension oriented transversely to the first axis of rotation, with the extension delimiting the tank space in sections on a radially inner side. The extension preferably delimits the tank space directly. Precisely two control kidneys are preferably provided, with one suction-side control kidney being permanently connected to the tank space, and the other pressure-side control kidney being permanently connected to a second filter connection, which is most preferably arranged on the peripheral surface of the connection part. A first filter connection on the peripheral surface of the connection part is preferably permanently connected to the tank space. A third filter port on the peripheral surface of the control portion is preferably permanently connected to a feed valve assembly.

It can be provided that the main pump is arranged on the side of the connecting part opposite the extension in the direction of the first axis of rotation, whereby it bears against a pump sealing surface of the connecting part oriented transversely to the first axis of rotation, wherein in At least one first pump connection is arranged in the region of the pump sealing surface, which is permanently connected to the first working connection, wherein at least one second pump connection is arranged in the region of the pump sealing surface, which is permanently connected to the second working connection. The feed pump can thus be installed particularly easily in the connection part. At the same time, the tank space is easily accessible from the outside in order to hold a casting core there when casting the blank of the connection part. The connections mentioned above are preferably each formed by a channel which is directly delimited by the connection part. A separate distribution plate of the main pump is preferably in contact with the pump sealing surface. The pump sealing surface is preferably flat and aligned perpendicular to the first axis of rotation. It can have a centering step, with which a pot-like housing part is aligned on the connection part.

Provision can be made for the feed pump to be designed as an internal gear pump, with the outer part being provided with internal gearing which meshes with external gearing on the inner part, with the outer part being accommodated in a separate bearing part so that it can rotate with respect to a second axis of rotation, the second axis of rotation being parallel and is arranged at a distance from the first axis of rotation, the bearing part partially delimiting a radially inner side of the tank space. The bearing part preferably delimits the tank space directly. The corresponding radially outer side of the bearing part is preferably circular-cylindrical with respect to the first axis of rotation. The tank space is preferably delimited exclusively by the connection part and the bearing part.

A separate filter can be provided, which is attached to a filter sealing surface, with the filter sealing surface being formed by the peripheral surface of the connection part, with a first, a second and a third filter connection being arranged in the area of the filter sealing surface, with the first filter connection being permanently attached to the Tank room is connected, wherein the second filter port is permanently connected to a pressure side of the feed pump. In the case of conventional hydraulic machines, such a filter requires piping on the outside of the hydraulic machine, which the user of the hydraulic machine has to produce. The annular tank space according to the invention makes it possible to dispense with such an external piping. The filter preferably comprises a filter base which is attached to the filter sealing surface in a fluid-tight manner, with a separate filter cartridge being accommodated in an exchangeable manner in the filter base. The pressurized fluid preferably flows from the second filter port via the filter cartridge to the third filter port. The filter sealing surface is preferably flat.

It can be provided that the filter includes a cold start valve which directs at least part of the pressure fluid to the first filter port when either the pressure difference between the third and second filter port or the pressure at the second filter port exceeds a predetermined limit value. Such a cold start valve represents a preferred option for using the first filter connection, which is connected to the annular tank space. It goes without saying that the invention can be used with any other design of a filter which uses a corresponding first filter connection. The cold start valve is preferably accommodated in the filter base. The cold start valve is preferably designed in the manner of a pressure relief valve.

Provision can be made for the at least one tank connection and possibly the first filter connection to be connected to the tank space exclusively via a channel which is directly delimited by the connection part. The second filter connection is preferably connected to the pressure side or the pressure-side control kidney of the feed pump via a channel which is directly delimited by the connection part. The channels mentioned above are preferably produced as far as possible during the casting of the blank of the connection part, so that at most short sections of the channels mentioned are formed by bores produced after the casting.

Provision can be made for a feed valve arrangement to be accommodated in the connection part, via which pressure fluid can be routed from at least one tank connection by means of the feed pump to the low-pressure working connection of a group which includes the first and the second working connection. Preferably, the feed valve arrangement for the first and the second working port each includes a separate built-in or screw-in valve, which most preferably includes a check valve and a pressure-limiting valve.

Provision can be made for the third filter connection to be permanently connected to the feed valve arrangement. The corresponding channel is preferably delimited directly by the connection part.

It goes without saying that the features mentioned above and those still to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

• 1 einen Schaltplan einer erfindungsgemäßen Hydromaschine;
• 2 eine perspektivische Ansicht der Hydromaschine nach 1;
• 3 eine weitere perspektivische Ansicht der Hydromaschine nach 1 von einer gegenüber 2 entgegengesetzten Seite her;
• 4 einen Längsschnitt des Anschlussteils mit der Speisepumpe;
• 5 eine perspektivische Ansicht des Anschlussteiles;
• 6 eine weitere perspektivische Ansicht des Anschlussteils von einer gegenüber 5 entgegengesetzten Seite her; und
• 7 eine perspektivische Ansicht des Innen-, des Außen- und des Lagerteils der Speisepumpe.

The invention is explained in more detail below with reference to the accompanying drawings. It shows:

• 1 a circuit diagram of a hydraulic machine according to the invention;
• 2 a perspective view of the hydraulic machine 1 ;
• 3 another perspective view of the hydraulic machine 1 from one opposite 2 opposite side fro;
• 4 a longitudinal section of the connector with the feed pump;
• 5 a perspective view of the connector;
• 6 another perspective view of the connector from one opposite 5 opposite side fro; and
• 7 a perspective view of the inner, the outer and the bearing part of the feed pump.

1 shows a circuit diagram of a hydraulic machine 10 according to the invention. The hydraulic machine 10 includes a main pump 30 and a feed pump 20, which are driven by a common drive shaft 16. In the present case, the main pump 30 is designed as an axial piston pump with a swash plate design. Its displacement volume can be continuously adjusted with an actuating cylinder 32, with the adjustment being able to take place beyond the displacement volume of zero.

In the present case, the feed pump 20 is designed as an internal gear pump with a constant displacement volume. It sucks the pressurized fluid through a tank port 42; 43; 44 on. The pressurized fluid is preferably a liquid and most preferably hydraulic oil. A special feature of the hydraulic machine 10 according to the invention is that the connection part is provided with a tank connection 42; 43; 44 can be provided, whereby the most favorable position is selected depending on the application. The remaining unused tank connections 42; 43; 44 are closed, for example, with a locking screw, although it is also conceivable that the corresponding connection bores are not drilled into the cast blank from the outset.

The feed pump 20 delivers the pressurized fluid from the selected tank port 42; 43; 44 to a filter 90. There it is filtered by means of a replaceable filter cartridge 92 before it is fed to the main pump 30. In the present case, the filter 90 is equipped with a cold start valve 91 . This directs part of the pressure fluid supplied by the feed pump 20 via the second filter connection 52 to the first filter connection 51 when the pressure drop across the filter cartridge 92 exceeds a predetermined limit value. The first filter port 51 is permanently connected to the selected tank port 42; 43; 44 connected. A special feature of the hydraulic machine 10 according to the invention is that the filter 90 can be attached directly to the connection part, with no additional piping being required on the outside of the hydraulic machine 10 . It should also be pointed out that the present cold start valve 91 represents only one of several possible valve variants that can be used in a filter 90 . All variants have in common that three filter connections 51; 52; 53 are used, the first filter connection 51 with the selected tank connection 42; 43; 44 is connected.

The present hydraulic machine 10 is intended for use in a closed hydraulic circuit. It therefore has a first and a second working connection 45; 46, neither of which is directly connected to the tank, which is connected to the tank connection 42; 43; 44 is connected. Rotational movement of the main pump 30 involves an exchange of pressurized fluid between the first and second working ports 45; 46 if a displacement volume other than zero is set on the main pump 30. With the feed pump 20, the pressure fluid is replaced, which is lost, for example, in an undefined way through leaks or specifically via a flushing valve from the closed hydraulic circuit. For this purpose, a feed valve arrangement 80 is provided, which feeds the pressure fluid flowing in from the third filter connection 53 either to the first or to the second working connection 45; 46 heads. Each of the two working connections 45; 46 is assigned a built-in valve 81 which includes a check valve 82 and a first pressure-limiting valve 83 in each case. The check valve 82 only allows a flow of fluid from the third filter port 53 to the associated first or second working port 45; 46 to. As a result, the pressure fluid flowing in from the third filter connection 53 flows to the lower-pressure of the two working connections 45; 46. The first pressure relief valve 83 limits the pressure at the associated working port 45; 56 up.

Reference should also be made to the second pressure-limiting valve 15, which limits the pressure at the third filter connection 53 upwards.

2 shows a perspective view of the hydraulic machine 10 after 1 . 3 shows a further perspective view of the hydraulic machine 10 1 from one opposite 2 opposite side. The main pump and the feed pump are surrounded by a common housing 14, which is composed of a connection part 40 and a pot-like housing part 31, the connection part 40 being the open side of the pot-like housing part 31 is covered in a fluid-tight manner. In the pot-like housing part 31, the main pump is accommodated, for example, according to DE 10 2017 211 750 A1 or the DE 10 2007 011 644 B4 can be executed.

Both the main pump and the feed pump can be driven with the drive shaft 16 which is rotatable with respect to the first axis of rotation 11 . The present hydraulic machine 10 is equipped with a through drive, i.e. the drive shaft 16 is accessible in the direction of the first axis of rotation 11 from two opposite sides for drive purposes.

The one-piece connection part 40 is plate-like, i.e. it has a substantially constant thickness in the direction of the first axis of rotation 11 . In the present case, a total of three tank connections 42; 43; 44 are provided, which are arranged offset from one another by 90° with respect to the first axis of rotation 11 . The filter base 93 of the filter is installed at the remaining fourth 90° angular position. The tank connections 43 and 44 are not used in the present case, which is why they are sealed in a fluid-tight manner with a separate screw plug. The present tank port 42 used is between the first and second working ports 45; 46 arranged. Which of the tank connections 42; 43; 44 is used is left to the user of the hydraulic machine 10. An advantage of the invention is that all three options are essentially hydraulically equivalent.

The already mentioned filter cartridge 92 is inserted into the filter base 93 and can be exchanged by the user with little effort. An advantage of the invention is that the filter does not require any piping on the outside of the hydraulic machine 10 that would have to be installed by the user of the hydraulic machine 10 .

In 2 and 3 the two built-in valves 81 mentioned above, which are accommodated in the connection part 40, can also be seen.

4 shows a longitudinal section of the connection part 40 with the feed pump 20. The feed pump 20 has an inner part 21 which is connected to the drive shaft 16 in a torque-proof manner. It should be noted here that in 4 only part of the drive shaft 16 is shown. The inner part 21 is surrounded by an annular outer part 22, which has the in 7 toothed engagement shown is taken along so that it rotates together with the inner part 21 . The outer part 22 is rotatably mounted in a separate bearing part 23 . The bearing part 23 is firmly connected to the connection part 40 . It is clamped by a holding plate 26 in the direction of the first axis of rotation 11 against the connection part 40 , its rotational position being fixed by means of a cylindrical pin 27 .

The inner part 21 , the outer part 22 and the bearing part 23 bear against a flat end face 71 of the connection part 40 . The end face 71 is arranged on an extension 70 of the connection part 40 , being level and aligned perpendicular to the first axis of rotation 11 . The extension 70, together with the bearing part 23, delimits a tank space 13 from the radially inside. Otherwise, the tank space 13 is delimited by the connection part 40 . The tank space 13 runs in the form of a closed ring around the extension 70 and the bearing part 23 . It can therefore be drilled from the peripheral surface 41 in any angular position with respect to the first axis of rotation 11 over a short distance. As a result, the tank connections 43; 44 can be arranged at almost any point on the peripheral surface 41. The 90° offset of the tank connections explained above is essentially due to the cost-effective production of all bores in the connection part 40 .

Within the extension are the suction-side and the pressure-side control kidney 72; 73 (see also 5 ) of the feed pump 20 is arranged. The suction-side control kidney 72 is equipped with an in 4 non-visible channel permanently connected to the tank space 13, this channel is limited exclusively by the connector 40. Because of the annular shape of the tank space 13, this channel can be made very short, and it is easy to produce. It can be formed entirely from the cast blank of the fitting, it being conceivable that part of this channel is drilled after casting.

The pressure-side control kidney 73 is connected via another channel, which is in 4 also not visible, permanently connected to the second filter port (#52 in 5 ) tied together. This channel is also exclusively delimited by the connecting part 40 , it preferably being present completely in the cast blank of the connecting part 40 .

5 shows a perspective view of the connection part 40. The extension 70 already mentioned can be seen first, on the end face 71 of which the suction-side and the pressure-side control kidney 72; 73 of the feed pump are arranged. A gap 47 can be seen around the extension 70, which in the fully assembled hydraulic machine 10 is caused by the bearing part (No. 23 in 4 ) is closed. The casting core, which delimits the annular tank space 13 as part of the casting mold, can be held in the desired position from the outside without any problems via this gap 47 the. It should be noted that during the casting of the blank of the fitting 40, none of the tank fittings 42 ( 3 ); 43; 44 and also not the first filter connection 52 are available to hold the corresponding casting core. The mentioned connections 42 ( 3 ); 43; 44, 52 are only drilled after casting.

Next is in 5 to recognize the flat filter sealing surface 50 on which the filter base (No. 93 in 3 ) is mounted in a fluid-tight manner, in particular where it is screwed. There are the first, the second and the third filter connection 51; 52; 53 arranged. The third filter port 53 is connected via the feed valve assembly (#80 in 1 ) to the first and second pump ports (#61; 62 in 6 ) connected on the opposite side of the connector 40. These ducts are also delimited exclusively by the connection part 40, and they are largely already produced when the blank part of the connection part 40 is cast.

For the tank connections 43; 44 a separate socket 48 is provided on the connection part 40 in each case. This provides the desired wall thickness around the corresponding bores in connector 50 while minimizing the amount of material required for connector 40 at the same time.

6 shows another perspective view of the connector 40 from an opposite 5 opposite side. The flat pump sealing surface 60 which is aligned perpendicular to the first axis of rotation 11 can be seen. The already mentioned first and second pump connections 61; 62 out. The two first pump ports 61 are permanently connected to the first working port 45 , the two second pump ports 62 being permanently connected to the second working port 46 . The corresponding channels are in turn exclusively delimited by the connection part 40 . A separate distribution plate of the main pump, on which the actual control kidneys of the main pump are arranged, preferably rests on the pump sealing surface 60 . But it is also conceivable that the first and the second pump connections 61; 62 form the control kidneys of the main pump.

Reference should also be made to the centering shoulder 49, which is circular with respect to the first axis of rotation 11 and with which the pot-like housing part (no. 30 in 2 ) is aligned with the connector.

7 shows a perspective view of the inner, the outer and the bearing part 21; 22; 23 of the feed pump. The inner part 21 is provided with an outer toothing 25 which meshes with an inner toothing 24 on the outer part 22, resulting in an internal gear pump. The outer part 22 is rotatable with respect to a second axis of rotation 12 which is arranged at a distance from and parallel to the first axis of rotation 11 . The outer part 22 has an outer peripheral surface which is circular-cylindrical with respect to the second axis of rotation 12 and which is received in an adapted inner peripheral surface of the bearing part 23 in order to bring about the rotational bearing already mentioned with respect to the second axis of rotation 12 .

Reference List

10

hydro machine

11

first axis of rotation

12

second axis of rotation

13

tank room

14

Housing

15

second pressure relief valve

16

drive shaft

20

feed pump

21

inner part

22

outer part

23

bearing part

24

internal teeth

25

external teeth

26

Retaining plate

27

cylindrical pin

30

main pump

31

pot-like housing part

32

adjusting cylinder

40

connector

41

Peripheral surface of the connecting part

42

tank connection

43

tank connection

44

tank connection

45

first working port

46

second working port

47

gap

48

base

49

center heel

50

filter sealing surface

51

first filter connection

52

second filter connection

53

third filter port

60

pump sealing surface

61

first pump connection

62

second pump connection

70

extension

71

face of the extension

72

intake-side control kidney

73

pressure-side control kidney

80

feed valve assembly

81

cartridge valve

82

check valve

83

first pressure relief valve

90

filter

91

cold start valve

92

filter cartridge

93

filter base

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102007011644 B4 [0002, 0023]
• DE 102017211750 A1 [0023]

Claims (9)

Hydraulic machine (10) comprising a main pump (30) and a feed pump (20) which have a common first axis of rotation (11) and are accommodated in a common housing (14), the housing (14) having a one-piece connection part (40 ), wherein the connection part (40) has a circumferential surface (41) with respect to the first axis of rotation (11), at least one tank connection (42; 43; 44) being arranged on the circumferential surface (41) and permanently connected to a tank space (13 ) is connected within the housing (14), the tank space (13) being delimited at least in sections by the connection part (40), a first and a second working connection (45; 46) being arranged on the peripheral surface (41), the feed pump (20) comprises an inner part (21) which can be rotated with respect to the first axis of rotation (11) and is surrounded by an annular outer part (22), with a suction side of the feed pump (20) being permanently connected to the tank space (13), characterized in that the s the tank space (13) runs in the form of a closed ring around the outside of the outer part (22) of the feed pump (20). Hydraulic machine (10) after claim 1 , wherein the connecting part (40) has an extension (70) pointing in the direction of the first axis of rotation (11), wherein at least two control kidneys (72; 73 ) of the feed pump (20) are arranged, wherein the extension (70) delimits the tank space (13) in sections on a radially inner side. Hydraulic machine (10) after claim 2 , wherein the main pump (30) is arranged on the side of the connecting part (40) opposite the extension (70) in the direction of the first axis of rotation (11), being on a pump sealing surface (60) of the connecting part oriented transversely to the first axis of rotation (11). (40), with at least one first pump connection (61) being arranged in the area of the pump sealing surface (60), which is permanently connected to the first working connection (45), with at least one second pump connection (62 ) is arranged, which is permanently connected to the second working connection (46). Hydraulic machine (10) according to one of the preceding claims, wherein the feed pump (20) is designed as an internal gear pump, the outer part (22) being provided with an inner toothing (24) which meshes with an outer toothing (25) on the inner part (21), wherein the outer part (22) is accommodated in a separate bearing part (23) so that it can rotate relative to a second axis of rotation (12), the second axis of rotation (12) being arranged parallel to and at a distance from the first axis of rotation (11), the bearing part (23) a radially inner side of the tank space (13) delimited in sections. Hydraulic machine (10) according to one of the preceding claims, wherein a separate filter (90) is provided, which is attached to a filter sealing surface (50), the filter sealing surface (50) being formed by the peripheral surface of the connecting part (40), the region a first, a second and a third filter connection (51; 52; 53) are arranged on the filter sealing surface (50), the first filter connection (51) being permanently connected to the tank space (13), the second filter connection (52) being permanently connected to a pressure side of the feed pump (22) is connected. Hydraulic machine (10) after claim 5 , wherein the filter (90) comprises a cold start valve (91) which directs at least part of the pressurized fluid to the first filter port (51) when either the pressure difference between the third and second filter port (53; 52) or the pressure at the second filter port ( 52) exceeds a specified limit. Hydraulic machine (10) according to one of the preceding claims, wherein the at least one tank connection (42; 43; 44) and, if applicable, the first filter connection (52) each communicate with the tank space exclusively via a channel which is directly delimited by the connection part (40). (13) is connected. Hydraulic machine (10) according to one of the preceding claims, wherein a feed valve arrangement (80) is accommodated in the connection part (40), via which pressure fluid from the at least one tank connection (42; 43; 44) by means of the feed pump (20) to the low-pressure working connection of a group , which comprises the first and the second working port (45; 46), is conductive. Hydraulic machine (10) after claim 8 , referring back to claim 5 wherein the third filter port (53) is permanently connected to the feed valve assembly (80).

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