Patent Application
20130121854
This application claims priority to German Patent Application No. 102011055194.1, filed Nov. 10, 2011. The entire disclosure of the above application is incorporated herein by reference.
The disclosure relates to a gearbox with a hydraulic pump arrangement that has a hydraulic pump with two flow directions. The hydraulic pump has a first hydraulic port and a second hydraulic port. In this case, the hydraulic pump arrangement is formed such that it functions independent of rotational direction. Accordingly, hydraulic fluid is delivered through a discharge in both possible flow directions.
A hydraulic pump arrangement is known from DE 10 2010 010804 A1. The disclosed hydraulic pump is arranged in a housing flange portion of a gearbox. The housing flange portion covers a recess of the gearbox housing. The housing flange portion has an axially projecting extension where several modules of the hydraulic pump are arranged axially one behind the other. Furthermore, bores and valves are provided in the housing flange portion, which enables delivery of the hydraulic fluid independent of the rotational direction.
It is object of the present disclosure, to provide a specifically simple structure for a rotational independent hydraulic connection of the hydraulic pump arrangement.
The object is achieved by a gearbox with a hydraulic pump arrangement that comprises a hydraulic pump with two flow directions. The hydraulic pump has a first hydraulic port and a second hydraulic port. The hydraulic pump arrangement includes a first feed and a first discharge, both of which are connected to the first hydraulic port. A second feed and a second discharge are connected to the second hydraulic port. A non-return valve is arranged in each feed and in each discharge.
The feeds of the hydraulic pump arrangement are connected to an oil sump of the gearbox. Thus, oil can be delivered from the oil sump of the gearbox to the lubricating points of the gearbox or to further components to be lubricated.
The hydraulic pump is driven by a drive shaft of the gearbox. The drive shaft of the gearbox includes at least one gear. The gearbox has a gearbox housing with a housing bottom. The oil sump is arranged in the housing bottom. An accommodation chamber is provided in the housing bottom to accommodate the gear of the drive shaft. The accommodation chamber separates the oil sump into a first sump chamber and into a second sump chamber. The first feed of the hydraulic pump arrangement is connected to the first sump chamber. The second feed of the hydraulic pump arrangement is connected to the second sump chamber.
The non-return or check valves in the feeds open in the direction to the respective hydraulic port. The non-return or check valves in the discharges close in the direction to the respective hydraulic port. If the hydraulic pump is driven in one direction where the suction side is at the first hydraulic port and the pressure side is at the second hydraulic port, the non-return valve in the first feed opens. The non-return valve in the first discharge closes, as this is laid out to close in the direction to the first hydraulic port. Thus, hydraulic fluid is sucked in from the first feed. On the pressure side, at the second hydraulic port, the non-return valve at the first discharge opens. The non-return valve in the second feed closes, as this only opens in the direction to the second hydraulic port. Thus, it is closed by the hydraulic pressure against this direction.
In the other case, where the hydraulic pump is driven such, that the pressure side occurs at the first hydraulic port and the suction side occurs at the second hydraulic port, the non-return valve in the first feed is closed and the non-return valve in the first discharge opens. However, the non-return valve in the second feed is opened and the non-return valve in the second discharge is closed. Thus, hydraulic fluid is pumped from the second feed to the first discharge.
In a preferred embodiment, both discharges are connected to a joint discharge line. Thus, the hydraulic pump arrangement has only one discharge line and one discharge port in spite of the two discharges. Preferably, the hydraulic pump is a gear pump, a vane pump or a piston pump.
The two sump chambers can be connected to each other via a connection passage. The accommodation chamber for the gear of the drive shaft is necessary for a compact design. The gear of the drive shaft has to be arranged as close as possible to the lower gearbox bottom of the gearbox housing. This means, however, that without an accommodation chamber, the gear of the drive shaft would enter the oil of the oil sump and would catapult the oil upwards due to rotation. In this case the danger exists that air would be sucked in by the oil pump because of the agitated oil. To prevent this, the accommodation chamber extends up to the level of the oil sump or just below the oil level of the oil sump. Thus, the oil that flows to lubricate the gears of the gearbox flows, downwards due to gravity, partially directly into the oil sump and also into the accommodation chamber. In the accommodation chamber, the oil is then catapulted upward due to the rotation of the gear of the drive shaft. The oil is, preferably, catapulted over a wall of the accommodation chamber up to an outer wall of the gearbox housing. From here, the oil flows directly into the oil sump. No gear of the gearbox enters the oil in the oil sump. Thus, settling of the oil takes place and no danger exists that air will be sucked in by the hydraulic pump arrangement.
Preferably, the hydraulic pump has a pump housing, that is detachably connected to the gearbox housing. Thus, a compact design of the gearbox, including the hydraulic pump arrangement, is ensured. Alternatively, the pump housing can also form part of the gearbox housing, in the form of a housing extension.
The pump housing can have two inlet openings, that are connected to the bores in the gearbox housing leading to the sump chamber. The non-return valves of the feeds are arranged in the bores of the gearbox housing.
The hydraulic pump can be modularly constructed and can include an inlet module, a pump module and an outlet module. The modules are detachably connected to each other. Connection passages, that extend from inlets to the hydraulic pump, are provided as part of the feeds in the inlet module. The hydraulic pump, especially the gears of a gear pump, is provided in the pump module. In the outlet module, connection passages are provided as part of the discharges. The connection passages extend from the hydraulic pump to a joint outlet of the discharges. Thus, by a simple exchange of the individual modules, the hydraulic pump can be adapted to different requirements. Different large pump modules with different outputs can be provided. Thus, depending on the necessary delivery output, a corresponding pump module can be used. As the pump module is not part of the gearbox or of the gearbox housing, no special cast pieces need to be provided that have to be adapted to the different pump outputs. The individual modules are, respectively, encapsulated to the outside or sealed, so that they represent their own housing. Depending on the pump output, the whole hydraulic pump, consisting of the individual modules, will differ in length.
A pump drive shaft is provided for the drive of the hydraulic pump. The drive shaft is passed from the pump module to the inlet module. The pump drive shaft is passed through a bore in the gearbox housing and is, drive-wise, detachably connected within the gearbox housing to a drive shaft of the gearbox.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
In the following, a preferred embodiment is described in detail by using the drawings. It shows
In
The non-return valve 10 in the second discharge line 8 opens towards the discharge line 14. The check valve 10 closes in the direction to the second hydraulic port 4. The non-return valve 12 of the first discharge line 6 opens in the direction to the discharge line 14 and closes in the direction to the first hydraulic port 3. Thus, the two non-return valves 10, 12 of the two discharge lines 6, 8 close, respectively, in the direction to the hydraulic pump 2 and open in the direction to the discharge line 14.
As indicated by the arrows of the hydraulic pump 2, the hydraulic pump 2 can be driven in two rotational directions. In a first rotational direction, hydraulic fluid is pumped from the first hydraulic port 3 to the second hydraulic port 4. The first hydraulic port 3 is, thus, the suction side and the second hydraulic port 4 is the pressure side. Thus, a vacuum is present at the first hydraulic port 3. The vacuum opens the non-return valve 9 of the first feed line 5 in the direction to the first hydraulic port 3. Furthermore, the non-return valve 12 of the first discharge line 6 is closed because of the vacuum at the first hydraulic port 3.
At the pressure side, the side of the second hydraulic port 4, the non-return valve 10 in the second discharge line 8 is opened because of excess pressure in the direction to the discharge line 14. At the same time, the non-return valve 11 of the second feed line 7 closes. Thus, the hydraulic fluid is delivered from the oil sump 13 through the first feed line 5 via the hydraulic pump 2, to the second discharge line 8 and further to the discharge line 14.
When the hydraulic pump 2 is driven in a second rotational direction, which is in an opposite direction to the first rotational direction, the suction side is produced at the second hydraulic port 4. The pressure side occurs at the first hydraulic port 3. Thus, the non-return valve 10 of the second discharge line 8 is closed because of the vacuum at the second hydraulic port 4 in direction to the hydraulic pump 2. Instead, the non-return valve 11 in the second feed line 7 is opened in direction to the second hydraulic port 4. Thus, hydraulic oil is delivered from the oil sump 13 via the second feed line 7 to the second hydraulic port 4. At the pressure side, the side of the first hydraulic port 3, the non-return valve 9 of the first feed line 5 is closed because of the excess pressure in direction to the oil sump 13. Furthermore, the non-return valve 12 of the first discharge line 6 is opened in direction to the discharge line 14. Thus, the hydraulic fluid is delivered from the first hydraulic port 3 via the first discharge line 6 to the discharge line 14.
Thus, depending on the rotational driving direction of the hydraulic pump 2, oil is delivered from the first feed line 5 to the second discharge line 8 or from the second feed line 7 to the first discharge line 6. However, in both directions it is ensured, that the oil is delivered from the oil sump 13 to the discharge line 14. Thus, oil is always delivered, independent of the rotational driving direction of the hydraulic pump 2.
The gearbox housing 16 has a bore 20 at the side opposite the drive trunnion 19. The bore 20 is closed by the hydraulic pump arrangement 1. The hydraulic pump arrangement 1 is flanged via attachment screws 17 to the gearbox housing 16. The hydraulic pump arrangement 1 has a pump drive shaft 21 to drive the hydraulic pump 2. The pump drive shaft 21 is passed through the bore 20 into the inside of the gearbox housing 16. The pump drive shaft 21 is, drive-wise, directly connected via a shaft-hub-connection to the drive shaft 18. Thus, the hydraulic pump 2 is directly driven by the drive shaft 18 of the gearbox 15. Thus, it is directly driven by the drive unit driving the gearbox 15.
The gearbox housing 16 has a gearbox bottom 23. The oil sump 13 is formed in the gearbox bottom 23. The oil is accumulated in the oil sump 13. The oil has, within an accommodation chamber 63 (see
The hydraulic pump arrangement is structured modularly and has an inlet module 26, a pump module 27 as well as an outlet module 28. The individual modules 26, 27, 28 are connected to each other by locating pins 29, 30 and connecting screws 31, 32.
The first gear 35 is, drive-wise, connected to the pump drive shaft 21. Thus, the first gear 35 represents the driven gear 35. The second gear 36 is driven by the first gear 35 and is supported via a bearing shaft 37. The bearing shaft 37 is held and supported in the inlet module 26 and in the outlet module 28.
Furthermore, the inlet module 26 has a second opening 34 that is connected via a connection passage, in form of a second bore 40, to the second outlet opening 41. The second inlet opening is aligned with a second bore of the gearbox housing 16 and thus hydraulically connected to it. The second outlet opening 41 is aligned with the second hydraulic port 4 of the pump module 27 or the hydraulic pump 2 and thus, is hydraulically connected to it. The second inlet opening 34, the second bore 40 and the second outlet opening 41 form part of the second feed line 7 of
In the inlet module 26 several connection bores 44, 45, 46, 47 are provided, to accommodate the locating pins 29, 30 and the connecting screws 31, 32. Besides these connecting screws, further, not shown, screws are provided. Furthermore, at the inlet module 26, the attachment screws 17 (
A through bore 42 serves to enable passage of the pump drive shaft 21 through the gearbox housing 16. A bearing bore 43 serves to accommodate the bearing shaft 37.
The two bores 52, 53 are hydraulically connected to a discharge line 54. The discharge line 54 is in the form of a bore extending transversally to the two bores 52, 53. For this, the first bore 52 and the second bore 53 cross the discharge line 54. The openings of the bores 52, 53 are closed at the ends facing away from the inlet openings 50, 51 by dummy plugs 56, 57. The discharge line 54 ends in a discharge opening 55.
The outlet module 28 includes bearing bores 58, 59 to accommodate the pump drive shaft 21 and the bearing shaft 37. A connection bore 60 is shown that threadably receives one of the connecting screws 32.
To be able to maintain the oil level in both sump chambers 67, 68 at the same height, a connection passage 71 is provided to connect the two sump chambers 67, 68. The connection passage 71 extends transversally to the drive shaft 18 and is visible in
The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the gist of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102011055194.8 | Nov 2011 | DE | national |
