EP0925448A1

EP0925448A1 - Hydraulic pump and hydraulic engine

Info

Publication number: EP0925448A1
Application number: EP97919025A
Authority: EP
Inventors: Rudolf Mairle
Original assignee: Franz Xaver Meiller Fahrzeug und Maschinenfabbrik GmbH and Co KG
Current assignee: Franz Xaver Meiller Fahrzeug und Maschinenfabbrik GmbH and Co KG
Priority date: 1996-09-13
Filing date: 1997-09-02
Publication date: 1999-06-30
Anticipated expiration: 2017-09-02
Also published as: EP0925448B1; DE59711777D1; WO1998011345A1; KR20010029502A; KR100470361B1; DE19637419C1

Abstract

The invention relates to a hydraulic pump in which a pump drive mechanism is rotationally driven by a drive shaft and accomodated in a housing chamber. The housing has two connecting openings for the supply and discharge of the hydraulic fluid to and from the drive mechanism, wherein the housing chamber presents an enclosed area receiving leakage fluid, whereby the housing also comprises a pressure discharge channel extending from said area to one of the connecting openings and the pumping direction of the pump depends on the direction of rotation of the drive shaft. According to the invention a pressure discharge channel extending from the enclosed area of the housing chamber to the other opening is also provided and all of the connecting openings are designed to accommodate a connection adaptor, which when used closes the pressure discharge channel leading towards the connecting opening receiving it. Also disclosed is a hydraulic engine.

Description

"Hydraulic pump and hydraulic motor"

description

The invention relates to a hydraulic pump with a housing, a pump drive, which is accommodated in a chamber of the housing and is to be driven in rotation via a drive shaft, for conveying a hydraulic fluid, a first connection opening and a second connection opening for supplying or discharging the hydraulic fluid to and from the drive unit, wherein the housing chamber has a leakage fluid area from the pump engine, the housing also having a pressure relief channel extending from this space area to one of the connection openings and the direction of delivery of the hydraulic pump being dependent on the direction of rotation of the drive shaft.

The invention relates in particular to the field of hydraulic piston machines in which the engine is accommodated in a housing chamber filled with oil, which absorbs leakage due to internal leakage of the engine during the operation of the hydraulic piston machine. Undesirable high pressures can occur in the housing chamber when the machine is operating. In order to remedy this, it has already been proposed to provide a separate leakage oil line from the housing chamber to an external oil tank which contains the hydraulic working oil for the piston machine in such hydraulic pumps or hydraulic motors. However, such a separate leak oil line is particularly unfavorable because of the complex connection measures and the additional space requirement.

It has also already been proposed to provide an internal pressure relief channel between the engine housing chamber and the suction connection of the pump in the case of inclined axis pumps in order to reduce pressure in the engine housing chamber for suction. side of the pump. However, such hydraulic pumps may only be operated in one direction of rotation, since the connection connected to the pressure relief duct must be the suction connection. If the direction of rotation of such a hydraulic pump were changed, the delivery direction of the pump would be reversed and the pressure relief channel would be on the pressure side of the pump and introduce the output pressure of the pump into the engine housing chamber, which would lead to an impermissible pressure increase there. In order to remedy this, it has already been proposed to provide the connection openings of the pump on a common connection plate, in which the pressure relief duct is formed towards one of the two connection openings. Such a pump is shown, for example, in a brochure from Mannesmann Rexroth Brueninghaus Hydromatik with the brochure designation "KFA ... / 6, Index 1, constant pump; RDE 91500- L / 07.89". If such a pump is now to be operated in the opposite direction of rotation, the entire connection plate must first be removed and screwed back to the housing in a position rotated by 180 ° in order to move the connection provided with the pressure relief channel to the suction side of the pump. Such a modification of the connection plate is complex. In addition, there is a risk that the user will neglect the modification instructions - and the pump will then be operated with an impermissible direction of rotation.

Further proposals aim to secure the pressure relief duct of the type mentioned above with a check valve in order to separate the pressure-side pump connection opening from the engine housing chamber if the pump is connected incorrectly. Such a check valve in a separate pressure relief channel of the connection plate is difficult to implement and therefore means an increased design effort. Furthermore, such a check valve, which opens during normal pump operation when the pressure is reduced towards the suction connection, is noisy. The above-mentioned problems of pressure relief of the engine housing chamber occur in an analogous manner in hydraulic machines in the form of hydraulic piston motors, such as

such as swashplate, swash axis or wobble motors.

The invention also relates to a hydraulic motor with a housing, which is accommodated in a chamber of the housing and is acted upon by an hydraulic fluid for exerting a torque on an output drive shaft rotatably mounted in the housing, a first connection opening and a second connection opening for the Feeding or discharging the hydraulic fluid to and from the engine, the direction of rotation of the drive shaft being dependent on the way in which the hydraulic fluid flow is fed through the connection openings, the housing chamber also having a leakage fluid from the area receiving the engine.

The invention has for its object to provide a hydraulic pump of the type mentioned, in which the possibility of pressure reduction in the engine housing chamber to the pump suction side is realized with simple design measures and which is nevertheless quick and easy for operation with a changed direction of rotation of the drive shaft can be prepared while ensuring the pressure reduction function for the engine housing chamber.

To achieve this object, it is proposed according to the invention that the housing further has a pressure relief channel extending from the leakage fluid of the pump engine to the other connection opening, and that the connection openings for receiving a detachably attachable insert into the respective connection opening, with a passage for the hydraulic adapters to be delivered are set up, which in the inserted state closes the pressure relief duct leading to the connection opening receiving it, the connection adapter being inserted into the connection opening in each case, which forms the outlet connection opening of the hydraulic pump for the given delivery direction. In the solution proposed according to the invention, the hydraulic pump can be prepared correctly in a simple manner with respect to the hydraulic connection assignment for a given direction of rotation of the drive shaft in that the connection adapter to be connected to the pressure line or output line of the pump is inserted into the connection opening which is used for the given direction of rotation of the drive shaft forms the pressure-side outlet connection opening of the hydraulic pump. The other connection opening is then to be connected to an inlet line for the hydraulic fluid to be pumped. The connection adapter, which is preferably designed as a reducing connector, closes the pressure relief channel leading to this connection opening when it is inserted into the connection opening in question, thereby ensuring that no pressure transmission from the pressure-side outlet connection opening of the pump to the drive shaft housing chamber can take place via this pressure relief channel. The pressure relief channel at the other connection opening, which defines the suction side of the pump, remains free, so that the pressure reduction from the drive shaft housing chamber to the suction side of the pump can take place. If the hydraulic pump according to the invention is now to be driven, for example, by another drive source from which the drive shaft is rotated in the other direction of rotation, then the connection adapter to be connected to the pressure output line is to be inserted into the relevant other connection opening, which now forms the pressure-side output connection opening of the hydraulic pump. The suction-side connection opening of the pump is then connected to the inlet line from the outside. The hydraulic pump then has the correct hydraulic connection assignment for the given direction of rotation of the drive shaft and for the corresponding conveying direction, the pressure relief function for the engine housing chamber being ensured in turn, since the pressure relief channel at the connection opening, which now forms the suction-side connection opening, is open, whereas the Pressure relief duct at the pressure-side connection opening is closed by the connection adapter used. This flexible possibility of the connection preparation of the pump for any direction of rotation of the drive shaft is obtained with very simple design measures. The user can quickly change the connection without time-consuming conversion work.

In principle, it could be thought that a separate connection adapter with a locking function for the pressure relief channel in question is available for each connection opening, which can only be inserted into the connection opening assigned to it if it forms the output connection opening for a given direction of rotation of the drive shaft. However, the connection openings are preferably of the same design in such a way that one and the same connection adapter can optionally be inserted into each of the two connection openings.

Although the solution according to the invention can be applied, for example, to a radial piston pump, a particularly preferred embodiment relates to an axial piston pump controlled by means of a control plate or a control mirror. This can be a swash axis pump, a swash plate pump or a swash plate pump.

According to a preferred development, each of the two connection openings of the hydraulic pump has a respective bore section with a thread provided in a wall of the housing, in particular in the form of a cover plate, for screwing in a connection adapter provided with a corresponding counter-thread from the outside, each of the two connection openings via a communicates in each case in the housing wall and via a respective control slot of a control plate with pump cylinder chambers in a cylinder block of the pump engine, a through bore forming the relevant pressure relief channel extending to the chamber of the housing extending in a coaxial extension of the respective threaded bore section, and the connection adapter being attached has a closure element at its front end which closes the adjoining pressure relief duct when the connection adapter is screwed into one of the connection openings.

The closure element is preferably a sealing pin, which engages in a sealing manner when the connection adapter is screwed into a respective connection opening in the adjoining pressure relief channel.

The connection openings are preferably formed in a cover plate of the housing, whereas the control slots are formed in a control plate which is arranged on the inside of the cover plate and can be rotated and fixed in predetermined angular positions, the control plate in each case adjacent to an adjustment actuating surface for action by the sealing element of the connection adapter to a respective pressure relief channel, with one of the adjustment actuating surfaces in a first predetermined angular position of the control plate being aligned with its adjacent pressure relief channel in a readiness for adjustment position in such a way that when the connection adapter is screwed into the connection opening associated with this pressure relief channel, the sealing element of the connection adapter underneath Exercised a force that adjusts the control plate into a predetermined second angular position and thereby from the verse ready position is displaced, and wherein in this second predetermined angular position of the control plate, the other adjustment actuating surface is positioned in a corresponding ready position on the other pressure relief channel, from which the control plate can be adjusted back into the first predetermined angular position by screwing the connection adapter into the other connection opening .

Such a solution is proposed for hydraulic pumps in which it is for the control plate or the control mirror and the control slots formed therein for each conveying direction of the Hydropump gives a respective optimal angular position. These angular positions correspond to the above-mentioned predetermined first angular position and the predetermined second angular position. When the pump according to the invention is properly connected by inserting the connection adapter into the pressure-side connection opening, the correct optimal angular position of the control plate is automatically brought about by the sealing element twisting the control plate accordingly when the respective actuating surface is acted upon. The sealing element and the adjustment actuating surface in question act in the manner of a wedge thrust transmission, the sealing element and / or the adjustment actuating surface having a corresponding inclined surface section.

According to a development of the hydraulic pump according to the invention, the connection adapter contains a check valve in its passage for the working fluid. The check valve prevents the pump from being loaded with impermissibly high pressure from the connected consumer.

It is also an object of the invention to provide a hydraulic motor of the type mentioned above, in which the possibility of reducing pressure in the engine housing chamber for the hydraulic output connection of the hydraulic motor is implemented with simple structural measures and which is quick and easy for operation with a changed direction of rotation of the drive shaft can be prepared for the engine casing chamber while ensuring the pressure reduction function.

Starting from a hydraulic motor with the features of claim 8, this object is achieved according to the invention in that a pressure relief channel extends from the leakage area of the engine receiving space area of the housing chamber to each of the two connection openings and that the connection openings for receiving a detachably attachable into the relevant one Connection opening insertable, with a passage for the hydraulic fluid flow-provided connection adapters are set up, which, in the inserted state, closes the pressure relief channel leading to the connection opening receiving it, the connection adapter being inserted in each case into the connection opening via which the hydraulic fluid flow is fed to the engine.

The hydraulic motor according to the invention is based on similar considerations that have led to the hydraulic pump according to the invention. The hydraulic connection assignment is correct for a desired direction of rotation of the drive shaft if the connection adapter is inserted into the connection opening which forms the hydraulic input of the motor. The connection adapter prevents the high working pressure on the inlet side from being transmitted to the drive shaft housing chamber via the pressure relief channel at the inlet connection opening. On the other hand, the pressure relief channel at the hydraulic outlet connection opening is open and can provide pressure relief in the housing chamber. If the direction of rotation of the drive shaft is to be reversed, the hydraulic connections can be quickly and easily assigned correctly by inserting the connection adapter to be connected to the hydraulic supply line of the motor into the relevant other connection opening, which then forms the input connection. The remaining connection opening is then connected to the return line of the engine to the hydraulic tank without closing the associated pressure relief duct.

The hydraulic motor according to the invention is preferably designed as a piston motor, in particular an axial piston motor, in an oblique-axis construction, swashplate construction or swashplate construction.

According to a development of the hydraulic motor according to the invention, it is proposed that each of the two connection openings has a respective bore section provided in a wall of the housing, in particular in the form of a cover plate Thread for screwing a connection adapter provided with a corresponding mating thread from the outside, that each of the two connection openings communicates via a respective connecting channel in the housing wall and via a respective control slot of a control plate with working cylinder chambers in a cylinder block of the engine and that in a coaxial extension of the respective one Threaded bore section extends a through-hole forming the relevant pressure relief channel to the chamber of the housing, the connection adapter having at its front end a closure element which closes the pressure relief channel adjoining it when the connection adapter is screwed into one of the connection openings. The closure element is preferably a sealing pin, which engages in a sealing manner when the connection adapter is screwed into a connection opening in question in the pressure relief duct adjoining it.

According to a development of the hydraulic motor according to the invention, the connection openings are formed in a cover plate of the housing, whereas the control slots are formed in a control plate which is arranged on the inside of the cover plate and can be rotated and fixed in predetermined angular positions, the control plate also each having an adjustment actuating surface for actuation through the sealing element of the connection adapter adjacent to a respective pressure relief channel, one of the adjustment actuating surfaces in a first predetermined angular position of the control plate being aligned with the pressure relief channel adjacent to it in a readiness for adjustment position so that when the connection adapter is screwed into the connection opening associated with this pressure relief channel Sealing element of the connection adapter while exercising a ver the control plate in a predetermined second angular position acting force and thereby displaced from the readiness for adjustment, and being in this second predetermined angular position of the control plate the other adjustment actuation surface is positioned in a corresponding readiness for adjustment position on the other pressure relief channel, from which the control plate can be adjusted back into the first predetermined angular position by screwing the connection adapter into the other connection opening.

The above-mentioned solution relates to hydraulic motors in which there is a respective optimal angular position for the control plate for each flow direction of the hydraulic fluid flow and the corresponding direction of rotation of the drive shaft. The correct angle setting is automatically brought about by applying the relevant actuating surface through the sealing element when the hydraulic motor is prepared with regard to its hydraulic connection assignment for a desired direction of rotation of the drive shaft by screwing the connection adapter into the input connection opening.

The invention further relates to a connection adapter for a hydraulic machine in the form of a hydraulic pump according to one of claims 1 to 7 or a hydraulic motor according to one of claims 8 to 12, wherein the connection adapter is characterized in that it is a connection piece with a screw thread for screwing into a Connection opening of the hydraulic machine is formed and has a passage for the working fluid of the hydraulic machine and at its front end coaxial with its axis a sealing pin for closing a housing pressure relief duct of the hydraulic machine.

According to a development of the connection adapter according to the invention, a check valve is arranged in the passage.

The invention is explained in more detail below with reference to the drawings. FIG. 1 a shows a partially sectioned side view with a sectional plane according to BB in FIG. 1 b, an exemplary embodiment of the invention, which is a hydraulic machine with an inclined axis design that can be operated as a hydraulic pump or as a hydraulic motor.

Fig. Lb shows a plan view of a connecting plate of the hydraulic machine according to Fig. La.

Fig. 2 shows a sectional side view with section along the line II-II in Fig. Lb, a corresponding connection plate with inserted connection adapter.

FIG. 3 shows a modification of the exemplary embodiment according to FIG. 2 in a view corresponding to FIG. 2.

Fig. La shows a partial sectional side view of a hydraulic axial piston machine 1 in an inclined axis design. The axial piston machine 1 according to FIG. 1 a can be operated as an inclined-axis pump or as a hydraulic motor according to a basically known procedure. The associated connection adapter (see FIG. 60 in FIG. 2) is not shown in FIGS. 1a and 1b. The following considerations initially relate to use as a hydraulic inclined-axis pump.

The hydraulic axial piston machine 1 has an engine 5 accommodated in the housing 3, which comprises a drive shaft 9 which is rotatably mounted about the axis 7 and a cylinder drum 11 which has a plurality of working pistons 13 and a central bearing piston 14 for common rotation with the drive shaft 9 is connected, wherein the axis of rotation 15 of the cylinder drum 11 extends obliquely to the axis 7 of the drive shaft 9. The pistons 13 and 14 have ball joint heads (sliding shoes) 17 and 18 on their drive shaft end, which are articulated in complementary joint sockets 20 and 21 of the drive flange 23 of the drive shaft 9. On the cylinder drum side, pistons 13 and 14 engage in cylinder bores 25 and 26, respectively the cylinder drum 11, the cylinder bores 25 for the working pistons 13 being axially parallel and at a radial distance from the axis of rotation 15 of the cylinder drum 11, so that with the inclined axis geometry shown a reciprocating s stroke movement of the working piston 13, which is designed as a cone piston in the example, relative to the cylinder bores 25 takes place when the cylinder drum 11 rotates about its axis of rotation 15. Although only two working pistons 13 can be seen in FIG. 1 a, additional working pistons are preferably provided in a circular arrangement with the two working pistons shown.

Fluid channels 27 extend from the ends of the cylinder bores 25 remote from the drive shaft 9 to a control plate 29 (control mirror 29) which is fastened to the connecting cover plate 31 of the housing 3 and has a convex sliding surface 33 for the rotating cylinder drum 11, which is formed with a correspondingly concave counter surface 35.

20 The control plate 29 has, in a manner known per se, two arcuate control slots (not shown) along the orbit of the fluid channels 27 on the control plate 29, one of the control slots having a first connection opening 52 - and the other control slot having a second connection opening

25 54 is connected in the connecting cover plate 31 (see. Fig. Lb).

For the hydraulic relief of the pistons 13 and for the formation of a lubricating film on the piston shoes or joints 17, 20 30, the pistons 13 are provided with an axial passage channel 41 which communicates with the respective cylinder bore 25.

A corresponding measure is taken in the case of the axially central bearing piston 14, which supports the cylinder drum 11 radially 35 and prestresses in the axial direction toward the control mirror 29 by means of the compression spring 43. The axial through channel 45 of the bearing piston 14 is connected via a channel 47 in the connecting cover plate 31 to the housing chamber 50, in which the engine 5 is received.

5

The housing chamber 50 contains an oil filling and also receives leakage oil from the engine during the operation of the piston machine 1. So that no undesirably high pressures arise in the housing chamber 50, measures are taken to reduce the pressure in the housing chamber 50, which are explained below with reference to FIG. 2.

FIG. 2 shows a broken representation of the end of the piston machine 1 provided with the connecting cover plate 31 in a sectional view with a sectional plane according to II-II in FIG. 1b. The connection cover plate 31 which can be seen in section in FIG. 2 has the two connection openings 52, 54 for the supply and discharge of oil to and from the engine 5. The connection openings 52, 54 are provided with an internal thread 56, 58 0, so that connection adapters or connection pieces 60, 62 can be screwed into the connection openings 52, 54. As can also be seen in FIG. 2, the connection openings 52, 54 have a respective through-hole 64 or 66 of the connection cover plate 31 in the axial extension, the through-hole 64

25 at 68 - and the through hole 66 at 70 communicates with the housing chamber 50. In each case one of the through holes 64, 66 is used as an oil discharge channel for the purpose of reducing the pressure in the housing chamber 50. In FIG. 2, this is the through-hole 66 which carries excess oil from the housing chamber 50 to the

30 closing opening 54 can lead away. In the arrangement shown in FIG. 2, the through-bore 64 is closed by a sealing pin 72, which is provided at the front end of the connection adapter 60 screwed into the connection opening 52. The connection adapter designed as a reducer

35 60 has an oil passage 74 which, when the adapter 60 is screwed in, communicates with the base area 76 of the connection opening 52, which in turn communicates via a connecting channel 78 communicates with a control slot (not shown) of the control plate 29. To the outside, the output line of the pump is to be connected to the connection adapter 60.

As can also be seen from FIG. 2, a connecting channel 80 is also provided, which connects the base region of the connection opening 54 to the second control slot (not shown) of the control plate 29.

In contrast to the connecting adapter 60, the connecting piece 62 screwed into the connecting opening 54 has no sealing pin at its front end, so that the through-hole 66 is connected to the connecting channel 80 via the connecting opening 54.

It should be pointed out that the connecting pieces 60 and 62 are interchangeable, so that the connecting adapter 60 can be screwed into the connecting opening 54 - and the connecting piece 62 into the connecting opening 52, the sealing pin 72 always being screwed into the connecting adapter 60 correct position for closing the relevant bore 64 or 66.

If the piston machine 1 is operated as a hydraulic pump, the connection adapter 60 with the sealing pin 72 is to be inserted into the connection opening which forms the pressure side or the pump outlet. At the other connection opening, which then forms the pump inlet, pressure can then be released from the housing chamber 50 via the relevant bore (pressure relief channel 66 in FIG. 2) to the suction side of the pump.

If the piston machine 1 is operated as a hydraulic motor, the connection adapter 60 equipped with the sealing pin 72 is to be inserted into the connection opening 52 or 54, which forms the entrance for the working oil. Pressure relief from the housing chamber 50 can then take place to the other connection opening 52 or 54 via the relevant bore 64 or 66. When the piston machine 1 is operated as a hydraulic pump, the drive shaft 9 is set in rotation by an external drive source, the cylinder drum 11 being in rotationally driving connection with the drive shaft 9 via the working pistons 13 and rotating accordingly about the axis of rotation 15. In the course of each rotation of the cylinder drum 11, the working pistons 13 perform a suction stroke and a displacement stroke relative to the relevant cylinder bore 25 in order to draw in oil via one of the control slots (not shown) of the control plate 29 and the connection opening 52 or 54 communicating with this control slot and to deliver in the conveying direction via the other control slot of the control plate 29 and the relevant other connection opening 54 or 52.

The direction of delivery of the pump is dependent on the direction of rotation of the drive shaft 9. However, this fact can be countered in the hydraulic pump according to the invention without any noteworthy effort by screwing the connection adapter 60 into the connection opening 52 or 54 for a given direction of rotation of the drive shaft 9, which forms the pressure-side outlet opening of the pump in the given direction of rotation of the drive shaft 9. The sealing pin 72 then ensures in its sealing position in the relevant bore 64 or 66 that the housing chamber is not pressurized from the pressure side of the pump.

The suction connection piece 62, which is clearly recognizable on the outside from the connection adapter 60, is then inserted into the relevant other connection opening 54 or 52, which forms the suction side of the pump. Since the suction connection piece 62 does not close the relevant bore 66 or 64 at the connection opening 54 or 52 receiving it, pressure relief of the housing chamber 50 to the suction side of the pump can take place via the relevant bore. If, under other operating conditions, there is a drive source for the drive shaft 9 which only provides the opposite direction of rotation for the drive shaft 9, the inventive The hydraulic pump can be adapted quickly by exchanging the connecting pieces 60 and 62 for one another. Then it is ensured again that the housing chamber 50 can find pressure relief towards the suction side of the pump and that the sealing pin 72 of the connection adapter 60 closes the relevant bore 66 or 64 at the pressure-side connection opening 54 or 52. In the hydraulic pumps according to the invention, it is therefore not necessary to take into account the direction of rotation of the available drive source in terms of construction. The correct preparation of the hydraulic pump connections can be carried out quickly and flexibly for a given drive source by screwing in the connection adapter 60 with sealing pin 72 and connection opening 52 or 54, which forms the 5 pressure side of the pump for the given drive direction of the drive source. Accordingly, the suction connection piece 62 can then be screwed into the other connection opening 54 or 52.

A piston machine with the construction 0 shown in the figures can also operate as a hydraulic motor. become. In this case, working oil is supplied to the engine 5 via one of the connection openings 52 or 54 under pressure in order to generate a working stroke of the working pistons 13 which are respectively connected to this connection opening via a respective control slot of the control plate 29. This working stroke is transformed on the basis of the engine geometry m into a rotational movement of the drive shaft 9. At the same time, the working pistons 13 0, which are connected in each case via the other control slot of the control plate 29 to the other connection opening 54 or 52, carry out an oil displacement stroke to the hydraulic output side of the hydraulic motor. The direction of rotation of the drive shaft J depends on which of the connection openings 52, 54 of the working oil flow is supplied to the engine 5 and which of the connection openings 52, 54 of the work ts 5lεtroπi is discharged. 5 The connection adapter 60 with sealing pin 72 is in each case in the connection opening 52 or 54 to use, which should form the inlet opening for the working oil flow. The pressure relief the chamber 50 then takes place towards the relevant other connection opening 54 or 52, which forms the outlet for the working oil flow. If the direction of rotation of the hydraulic motor is now to be changed, the hydraulic connection conditions can be quickly corrected again by exchanging the connecting pieces 60 and 62, the working oil flow then being supplied via the connecting adapter 60 and discharged via the connecting piece 62. Such a hydraulic motor according to the invention can therefore be prepared quickly and flexibly for a desired direction of rotation of the drive shaft 9 on the hydraulic connection side.

FIG. 3 shows in a view corresponding to FIG. 2 a modification of the exemplary embodiment of a hydraulic axial piston machine according to the invention described above.

In the variant according to FIG. 3, the control plate (control mirror 29) can be adjusted and fixed between two predetermined angular positions relative to the axis of rotation 15 of the cylinder drum 11 and is accordingly rotatably fastened to the connecting cover plate 31. Each of the two angular positions of the control plate 29 corresponds to an optimal setting of the control slots contained therein for a respective direction of rotation of the cylinder drum 11. An additional special feature of the exemplary embodiment according to FIG. 3 is that the correct angle of rotation setting of the control plate 29 automatically by screwing in the connection adapter 60 in the relevant connection opening 52 or 54 can be brought about, which forms the output connection opening in the case of the hydraulic pump - and the input connection opening in the case of the motor.

For this purpose, the control plate 29 has two recesses on its peripheral edge, of which one, namely the recess 81, can be seen in FIG. 3. The recess 81 has an adjustment actuating surface 82 which, in the position according to FIG. 3, extends from the jacket region of a conical tip 84 of the sealing pin 72 of the connection adapter which engages in the recess 81. ters 60 is acted upon, the locking between the recess 81 and the tip 84 fixes the control plate 29 in the optimal angular position in the connection assignment shown. The second recess of the control plate 29, which cannot be seen in FIG. 3, is arranged at an angular distance of 180 ° minus the adjustment angle between the two optimal angular positions from the recess 81, so that the adjustment actuating surface of the second recess is close to the axis of the connection opening 54 and Pressure relief channel 66 lies. If the connection adapter 60 is now screwed into the connection opening 54 for the operation of the machine with the reverse direction of rotation of the drive shaft 9, the conical tip 84 of the connection adapter 60 engages in the other recess and acts on the associated adjustment actuating surface while exerting a wedge thrust force on the control plate 29 rotated into the second predetermined angular position, the connection adapter finally locking the control plate 29 in the second predetermined angular position. A corresponding return of the control plate 29 to the first predetermined angular position takes place when the connection adapter 60 is rotated again into the connection opening 52 while engaging the recess 81. As indicated schematically in FIG. 3 at 86, a check valve can be provided in the passage 74 of the connecting adapter of the piston machine, which, in the case of a hydraulic pump in question, secures the pump against impermissibly high pressure from the consumer.

Claims

claims

1. Hydraulic pump s with a housing (3), a in a chamber (50) of the housing (3), via a drive shaft (9) to be rotated to drive pump engine (5) for conveying a hydraulic fluid, a first connection opening (52) and one second connection opening (54) for the supply or discharge of the hydraulic fluid to and from the pump engine (5), the housing chamber (50) having a leakage fluid area from the pump engine (5), the housing (3) has a pressure relief channel (64 or 66) extending from this spatial area to one of the connection openings (52 or 54) and the delivery direction of the hydraulic pump depends on the direction of rotation of the drive shaft (9), characterized in that the housing (3) is furthermore 0 a pressure relief channel (66 or.) which extends from the leakage fluid of the pump engine (5) to the space area of the housing chamber (50) to the other connection opening (54 or 52) 64) and that the connection openings (52, 54) are arranged for receiving a detachably attachable insert into the respective connection opening (52 or 54) and provided with a passage (74) for the connection fluid (60) to be conveyed, which, in the inserted state, closes the pressure relief channel (64 or 66) leading to the connection opening 0 (52 or 54) receiving it, the connection adapter (60) in each case being inserted into the connection opening (52 or 54) which, for a given conveying direction, is the outlet connection opening of the Hydraulic pump forms. 5

Hydraulic pump according to claim 1, characterized in that that it is a piston pump.

3. Hydraulic pump according to claim 1 or 2, characterized in that it is an axial piston pump, in particular inclined-axis pump, swash plate pump or swash plate pump.

4. Hydraulic pump according to one of claims 1 to 3, characterized in that each of the two connection openings (52, 54) has a respective bore section with a thread for screwing in a with a in a cover plate (31) formed in particular the wall of the housing (3) has the corresponding counter thread provided from the outside that each of the two connection openings (52, 54) via a respective connecting channel (78 or 80) in the housing wall (31) and via control slots of a control plate (29) with pump cylinder chambers ( 25) communicates in a cylinder block (11) of the pump engine (5) and that a through bore (64 or 66) forming the relevant pressure relief channel extends to the chamber (50) of the housing (3) in a coaxial extension of the respective threaded bore section, wherein the connector adapter (60) has at its front end a closure element (72) which when screwing in the connector apters (60) in one of the connection openings (52 or 54) closes the adjoining pressure relief duct (64 or 66).

5. Hydraulic pump according to claim 4, characterized in that the closure element (72) is a sealing pin which seals when the connection adapter (60) is screwed into one of the connection openings (52 or 54) in the adjoining pressure relief duct (64 or 66) intervenes.

6. Hydraulic pump according to claim 4 or 5, characterized in that the connection openings (52, 54) are formed in a cover plate (31) of the housing, that the control slots in one on the inside of the cover plate (31) arranged and in predetermined Angular positions rotatably adjustable and fixable control plate (29) are formed such that the control plate (29) each has an adjustment actuating surface (82) for action by the sealing element (72) of the connection adapter (60) adjacent to a respective pressure relief channel (64, 66), whereby in each case one of the adjustment actuating surfaces (82) in a first predetermined angular position of the control plate (29) is aligned with the pressure relief channel (64 or 66) adjacent to it in a readiness for adjustment position so that when the connection adapter (60) is screwed into this pressure relief channel (64 or 66) associated connection opening (52 or 54) of the sealing element (72) the connection adapter (60) is subjected to a force that adjusts the control plate (29) into a predetermined second angular position and is thereby displaced from the ready-for-adjustment position, and in this second predetermined angular position of the control plate (29) the other adjustment actuating surface in a corresponding ready-for-adjustment position is positioned on the other pressure relief channel (66 or 64), from which the control plate (29) can be adjusted back into the first predetermined angular position by screwing the connection adapter (60) into the other connection opening (54 or 52).

7. Hydraulic pump according to one of the preceding claims, characterized in that the connection adapter (60) contains a check valve in its passage (74) for the hydraulic working fluid of the hydraulic pump.

8. Hydraulic motor with a housing (3), an engine (which is accommodated in a chamber (50) of the housing (3), to be driven by the application of a hydraulic fluid to exert a torque on an output drive shaft (9) rotatably mounted in the housing (3) ( 5), a first connection opening (52) and a second connection opening (54) for the supply or discharge of the hydraulic fluid to and from the engine (5), the direction of rotation of the drive shaft (9) depending on which of the connection openings (52 , 54) the hydraulic fluid flow is supplied, the housing chamber (50) also having a leakage fluid from the space receiving the engine, characterized in that the housing chamber (50) extends from this space to each of the two connection openings (52, 54 ) extends a pressure relief channel (64 or 66) and that the connection openings (52, 54) for receiving a detachably attachable into the connection opening (52 or 54) which can be used and which are provided with a passage (74) for the hydraulic fluid flow and which, in the inserted state, closes the pressure relief duct (64 or 66) leading to the connection opening (52 or 54) receiving them, wherein the connection adapter (60) is to be inserted into the connection opening (52 or 54) through which the hydraulic fluid flow is fed to the engine (5).

9. Hydraulic motor according to claim 8, characterized in that it is designed as a piston engine, in particular an axial piston engine in an inclined axis construction.

10. Hydraulic motor according to claim 8 or 9, characterized in that each of the two connection openings (52, 54) has a respective bore section with a thread provided in a wall of the housing (3), in particular in the form of a cover plate (31), for screwing in a connection adapter (60) provided with a corresponding mating thread from the outside, that each of the two connection openings (52, 54) via a respective connecting channel (78 or 80) in the housing wall (31) and via control slots of a control plate (29) with working cylinder chambers (25) in a cylinder block (11) of the engine (5) communicates and that in a coaxial extension of the respective threaded bore section extends a through-hole forming the relevant pressure relief channel (64 or 66) to the chamber (50) of the housing (3), the connecting adapter (60) at its front end a closure element (72) which, when screwing in the connection adapter (60) into one of the connection openings (52 or 54), connects to it forming pressure relief channel (64, 66) closes.

11. A hydraulic motor according to claim 10, characterized in that the closure element (72) is a sealing pin which engages sealingly when the connection adapter (60) is screwed into one of the connection openings (52 or 54) in the adjoining pressure relief duct (64 or 66) .

12. Hydraulic motor according to claim 10 or 11, characterized in that the connection openings (52, 54) are formed in a cover plate (31) of the housing, that the control slots in one on the inside of the cover plate (31) arranged and rotatable in predetermined angular positions adjustable and fixable control plate (29) are designed such that the control plate (29) each have an actuating actuating surface (82) for actuation by the Sealing element (72) of the connection adapter (60) adjacent to a respective pressure relief channel (64, 66), wherein one of the adjustment actuating surfaces (82) in a first predetermined angular position s of the control plate (29) to its adjacent pressure relief channel (64 or 66 ) in a readiness for adjustment is aligned so that when the connection adapter (60) is screwed into the connection opening (52 or 54) assigned to this pressure relief channel (64 or 66), it is removed from the sealing element (72) of the connection adapter (60) while the control plate ( 29) is subjected to a force adjusting a predetermined second angular position and is thereby displaced out of the readiness for adjustment position, and wherein in this second predetermined angular position of the control plate (29) the other adjustment actuating surface is positioned in a corresponding ready readiness position on the other pressure relief channel (66 or 64) is, au s the control plate (29) can be adjusted back into the first predetermined angular position by screwing the connection adapter (60) into the other connection opening (54 or 52).

13. Connection adapter for a hydraulic machine in the form of a hydraulic pump according to one of claims 1 to 7 or a hydraulic motor according to one of claims 8 to 12, characterized in that it as a connection piece with screw thread for screwing into a connection opening (52 or 54) of the hy - Drauliεchen machine is formed and a passage (74) for the working fluid of the hydraulic machine - and at its front end coaxial with its axis a sealing pin (72) for closing a housing pressure relief channel (64 or 66) of the hydraulic machine see.

14. Connection adapter according to claim 13, characterized in that a check valve is arranged in the passage (74).