EP1045142A2 - Pump housing - Google Patents

Abstract

The pump is enclosed in a pressure casing (15) in which are constructed pressure channels (60), with the pressure casing attached to a main casing (14) accommodating the pump unit (6). The pressure casing and pumps units are made of a high strength material, preferably steel, and the main casing is made of lower strength material, preferably aluminium or aluminium alloy. The pressure channel opens out into a housing (18) for the pump unit. An Independent claim is included for a fuel pump in a radial piston design has a pump casing in which up to three pump unit are housed.

Description

The invention relates to a pump housing for a hydrostatic Pump according to the preamble of the claim 1 and a fuel pump with such a Pump housing.

Hydrostatic pumps, i.e. according to the displacement principle working pumps are usually at higher operating pressures (mostly over 50 bar). Especially at High pressure pumps for common rail injection systems have become Radial piston pumps have proven to be particularly suitable because these have a comparatively simple structure and at minimal leakage allow high system pressures. These system pressures can be used with diesel common rail injection systems at up to 2000 bar and with gasoline common rail injection systems are up to 300 bar.

Conventional radial piston pumps have a pump housing, in which a drive shaft for driving several over the scope of distributed pump units is stored. Each Pump unit has a cylinder in which a piston is slidable is guided, which is on a shoe on a Eccentric of the drive shaft rests. They are also types known in which a piston in kinematic reversal Pump housing is fixed and the cylinder over the eccentric the drive shaft for suction and pressurization of the pressure medium is moved.

The requirements for such a pump housing exist in the fact that there is sufficient strength on the one hand must be in order to meet the high system pressures (300 bar, 2000 bar), on the other hand, one tries to to make the pump housing as light as possible, the vehicle weight and thus the fuel consumption lower. Conventional pump housings are commonly used made of cast iron, trying to suitable channel design and casting process the casting weight to minimize. The replacement of the comparatively heavy Cast iron is made of the highest quality light metal alloys currently not competitive due to cost reasons.

In contrast, the invention is based on the object a pump housing and one with such a pump housing engine power pump designed to create all Strength requirements are sufficient and inexpensive can be produced.

This task is done with regard to the pump housing by the features of claim 1 and in terms the fuel pump by the characteristics of the sibling Claim 10 solved.

According to the invention, the pressure channels and the suction channels each summarized in separate housing parts, see above that the parts exposed to a lower pressure load of the pump housing made of a material comparatively less Strength can be run while using High pressure areas of the pump housing a material of high strength are formed. Instead of the different materials can be the higher strength of the housing part that has the high-pressure channels by a suitable manufacturing process or a corresponding one Construction can be guaranteed. By suitable Material choice will get a pump housing that is inexpensive is producible and is characterized by a high pressure resistance with minimal weight. Another The advantage of this multi-part pump housing is that that the channel guide is significantly simplified because the Pressure channels and the suction channels in separate housing parts are trained.

The connection of the pressure housing containing the pressure channels to the main housing containing the suction channels particularly simple if the one assigned to a pump unit Pressure channel in the axial direction, i.e. parallel to the direction of movement of the piston opens into the pump unit. To this Way, the pressure medium can practically overhead from the Pump unit are discharged.

The pump housing can be made particularly compact, if the pressure housing on the front side to the main housing is flanged.

To simplify assembly, it is preferred if each pump unit on a flange plate or equivalent Part of the pressure housing is held, which in turn is attached to an end part of the pressure housing. In the Flange plate is then a connection channel, via which the pressure valve of the assigned pump unit with connected to the pressure channels in the front part of the pressure housing is.

The pre-assembly and manufacture of the pump housing will further simplified if the pressure relief valve in the pressure housing is arranged to limit the system pressure. It is preferred if the pressure housing also Suction port of the pump housing carries, so that in the main housing essentially the bearings for the drive shaft and the receptacles for the pumping units as well the suction channels must be formed. The suction connection is then via an inflow channel in the pressure housing with the Suction channels connected. With the pressure relief valve open then the suction and pressure channels via the inflow channel connected with each other.

Other advantageous developments of the invention are the subject of further subclaims.

Figur 1 einen Schnitt durch eine erfindungsgemäße Radialkolbenpumpe;

Figur 2 ein Detail X aus Figur 1;

Figur 3 eine schematische Darstellung eines Druckgehäuses für eine Radialkolbenpumpe gemäß Figur 1 und

Figur 4 ein weiteres Ausführungsbeispiel eines Druckgehäuses für eine Radialkolbenpumpe.

Preferred exemplary embodiments of the invention are explained in more detail below with the aid of schematic drawings. Show it:

1 shows a section through a radial piston pump according to the invention;

Figure 2 shows a detail X from Figure 1;

Figure 3 is a schematic representation of a pressure housing for a radial piston pump according to Figure 1 and

Figure 4 shows another embodiment of a pressure housing for a radial piston pump.

In the pump shown in longitudinal section in Figure 1 it is a radial piston pump 1, in which in a multi-part pump housing 2 a drive shaft 4 mounted is. About the drive shaft 4 three are even Pump units 6 distributed around the circumference. By doing The longitudinal section according to FIG. 1 is only one pump unit 6 visible, the other two pump units are at 120 ° offset above or below the drawing level. The drive shaft 4 has an eccentric 8 on which a Sliding bush an eccentric ring 10 is mounted.

The pump housing 2 shown in Figure 1 consists in essentially of a main housing 14 and a pressure housing 15. In the main housing 14 is an axial bore 16 for Bearing of the drive shaft 4 and in the radial direction opening receptacles 18 into which the pump units are formed 6 are used.

The axial bore 16 is step-like to that in FIG. 1 left end face 20 of the main housing 14 expanded. In the end face 20 are mounting holes for flanging the radial piston pump 1 is provided on a housing etc.

In the radially widened end section of the axial bore 16, a bearing bush 22 is used. This takes you Shaft sealing ring and plain bearing for radial and axial Bearing of the drive shaft 4.

The bearing bush 22 has an axial bore over which one Leakage from the seal assembly back into the low pressure area is feasible.

In the other, radially tapered end section of the Axial bore 16 are also slide bearings for radial / axial Support of the drive shaft 4 is provided.

In the area between these plain bearings Axial bore 16 an eccentric 24 in which the eccentric 8 is included with the eccentric ring 10 and the Suction port is filled with pressure medium.

FIG. 2 shows the area of the pump unit 6 in an enlarged manner Presentation. Accordingly, each pump unit 6 has one Cylinder 28, in which a piston 30 in the radial direction (based on the drive shaft 4) is slidably guided.

The piston 30 has one in the region of its end section Puncture in which a spring plate 32 is inserted. On this engages on a radial shoulder of the cylinder 28 supported compression spring 34. The face of the piston 30 rests on the inner end face of a sliding shoe 26, so that this via the compression spring 34 and the spring plate 32nd in its investment position against a flattening of the eccentric ring 10 is biased.

The front end of the pump unit 6 forms a Cylinder plate 36, which is penetrated by a pressure bore 38 is.

In the transition area between the pressure bore 38 and the cylinder bore receiving the piston 30 is a Suction valve 40 arranged, via the pressure medium (fuel) can be sucked out of the eccentric space 24. This is the eccentric space 24 via suction channels and not shown a suction groove 42 is connected to the pressure bore 38.

The cylinder plate 36 is of the radial direction (with reference to drive shaft 4) pressure bore 38 interspersed, even with the suction valve 40 closed a radial channel 44 is connected to the cylinder space, so that the pressurized pressure medium via the suction groove 42nd can flow in through the suction valve 40 and over the radial channel 44 and the pressure bore 38 via the pressure valve 46 in discharged the pressure channels described in more detail below can be.

As can be seen in particular in FIG Pump unit 6 via fastening screws 48 on one Fixed flange plate 50, which is part of the pressure housing 15 is. This flange plate is in turn via fastening screws 52 connected to the main housing 14. According to figure 1 is each flange plate with an end part 54 of the pressure housing 15 screwed.

Each flange plate 50 has an angular bore Connection channel 56, which has a short leg in the outlet of the pressure valve 46 and with a long one Leg opens into a channel 58 of the front part 54.

To seal the pump housing are between the Main housing 14, the front part 54 and the flange plates 50 Sealing arrangement provided, to which no further here to be received.

According to FIG. 1, the channel 58 goes into a pressure channel 60 over which the front part 54 in the radial direction (based on Drive shaft 4) penetrates. The pressure channel 60 goes into one Axial receptacle 62 above that in a hub-shaped projection 64 of the front part 54 opens.

The pressure channel 60 and the axial receptacle 62 are on the outer circumference or drilled from the front and by means of Locking screws closed, so that the manufacturing Minimal effort for the formation of these pressure channels is.

The projection 64 is in the radial direction from a connection hole 68 penetrates into a nipple 70 as a suction connection the radial piston pump 1 is used. The connection hole opens into an axially extending Inflow channel 72, which in turn is in a pocket 74 of the end face 76 of the end part 54 opens. For Sealing between the low pressure and high pressure areas the pocket 74 is gripped by a sealing ring 78, which is inserted into a receiving groove of the main housing 14 and rests on the end face 76 of the end part 54.

A not shown is in the axial receptacle 62 Pressure relief valve used, which is below the maximum pressure the connection from the pressure channel 60 to the connection bore 68 and blocked to the inflow channel 72. If exceeded of the maximum pressure opens the pressure relief valve this connection so that pressure medium from the pressure channel 60 can flow into the inflow duct 72.

In the embodiment shown in Figure 1 a flange plate 50 is assigned to each pump unit 6, which are screwed onto the common end part 54. In the flange plates 50 and the front part 54 are then practical all high pressure channels are formed, while in the main housing 14 only those with little Pressure pressurized suction channels are arranged. Instead of the multi-part flange plates 50 could also be a rotating one Housing part are provided on which the pump units 6 are attached.

To make it easier to understand what is shown in FIG The exemplary embodiment in FIG. 3 is a greatly simplified one Side view of the front part according to FIG. 1 shown. This has an approximately triangular or v-shaped Structure, the at the corner or end sections Flange plates 50 are screwed. For better support the flange plates, not shown, can be the corner areas of the front part 54 with enlarged support sections 80, 88, 90 are performed on which the flange plates 50 attachable via the indicated fastening screws 82 are.

The channels are then in these support sections 80, 88, 90 58 formed in the connecting channels 56 of the Flange plates 50 open.

The upper channel 58 in FIG. 3 is dash-dotted indicated pressure channel 60 with the axial receptacle 62 connected to the pressure relief valve (not shown).

The other two, not shown in Figure 1 Channels 58 assigned to pump units are each via one Connection pressure channel 84 or 86 with that in Figure 3 channel 58 located above or the pressure channel 60 connected. These connection pressure channels 84, 86 can also again from the end face of the assigned support section 88 or 90 are drilled out, so that the production of the pressure channel system is extremely simple. The pressure channel 60 and the Connection channels 84, 86 run in the one shown in FIG. 3 Embodiment in the region of the support section 80 together so that the pressure at all three pumping units 6 via the pressure relief valve inserted into the axial receptacle 62 is limited.

The pressure connection of the radial piston pump 1 becomes more advantageous Way also formed on the front part 54. So can this, as indicated for example in FIG. 3, as parallel bore running in the axial direction can be realized, into which a connector (not shown) is screwed becomes. Alternatively, the pressure connection can be as in FIG 1 can be arranged as bore 66.

As already mentioned, the geometry of the support part 54 not to the embodiment shown in Figure 3 limited. Alternatively, for example, a round one Support part (view according to Figure 3) or a pot-shaped housing are formed in the support part and flange plates are integrally formed. It is essential that the pressure channel system in a simple way through holes from Outer circumference or from the front side can be formed.

Instead of the triangular shape chosen in FIG according to FIG. 4, a V-shape for the front part 54 is also selected become. In this variant of the front part 54 are the Support sections 80, 88, 90 at the end or connecting sections two V-legs 92, 94 are formed. According to figure 4 run the two legs 92, 94 in the overhead Support section 80 together.

The connection pressure channels 84, 86 run along the longitudinal axis of the legs 92 and 94 and either open directly in the channel 58 of the support section 80 or - as in FIG 4 indicated - in the direction of the connecting channel 58 pressure channel extending to the connecting pressure channels 84, 86 60.

In this embodiment, the pressure relief valve in a receiving bore 96 of the leg 94 added. To provide more space for the pressure relief valve to be attached to create the leg 94 in the area the receiving bore 96 are expanded.

The bore 88 for the pressure connection is then more advantageous Formed in the other leg 92. Similar as in the previously described embodiment the receiving bore 96 via a not shown Inflow duct 72 with the low pressure area (suction ducts) in the Main housing 14 connected.

The suction port is in this embodiment advantageously formed on the main housing 14.

The channels 84, 86, 60 can again from the end faces the support sections 80 drilled here and then be closed with screw plugs.

The variant shown in Figure 4 stands out the embodiment shown in Figure 3 due to a further reduced weight with simplified Manufacturability. The flange plates are the same Way as in the embodiment shown in Figure 3 screwed to the front part 54.

In the embodiment shown in Figure 1 the main housing 14 is made of an aluminum alloy and the housing parts of the pump unit 6 and the flange plates 50 and the front part 54 made of a high-strength material, for example made of steel.

The construction according to the invention, in which both the Supply and discharge of the pressure medium in or from the displacement spaces in the axial direction is a Offset perpendicular to the drive axis possible.

Disclosed is a pump housing in which the high pressure pressurized channels in one or more separate Housing parts are formed. The one with the suction pressure charged areas are in a main body summarized. This construction enables the Main body in lightweight to manufacture, while with High pressure pressurized housing made of a high material Strength or in an appropriate design are.

Claims (11)

Pump housing for receiving at least one pump unit (6), the displacer (30) of a drive shaft (4) is driven, with suction channels in the pump housing (2) (42) for supplying a pressure medium to the pump unit (6) and pressure channels (44, 58, 56, 60, 84, 86) for removal of the pressurized pressure medium to one Pressure connection (88) are formed, marked through a pressure housing (15) in which the pressure channels (56, 60, 84, 86) are formed and that on one Pump unit (6) receiving main housing (14) attached is. Pump housing according to claim 1, characterized in that the pressure housing (15) and the pump units (6) made of a high strength material, preferably Steel are made and the main housing (14) a material of lower strength, preferably aluminum or there is an aluminum alloy. Pump housing according to claim 1 or 2, characterized in that that the pressure channel (56) axially in one Recording (18) for the pump unit (6) opens. Pump housing according to one of the preceding claims, characterized in that the pressure housing (15) on the end face, preferably on that of a drive shaft coupling side facing away from the main housing (14) is flanged. Pump housing according to claim 3, characterized in that the pressure housing (15) for each pump unit (6) has a flange plate (50) in which a connecting channel (56) is formed, via which the pressure channels (60, 84, 86) with the print side of the assigned Pump unit (6) are connected. Pump housing according to one of the preceding claims, characterized in that a suction port (70) is formed in the pressure housing (15) and via a Inflow channel (72) with the suction channels (24, 38, 42) connected is. Pump housing according to claim 6, characterized in that that in the pressure housing (15) a pressure relief valve is arranged over which the pressure channels (60, 84, 86) can be connected to the inflow channel (72). Pump housing according to one of the preceding claims, characterized in that in the main housing (14) several, for example three recordings (18) for Pump units (6) are formed, and that the pressure housing (15) with three pumping units approximately triangular or is V-shaped, with at the corner or end portions the hydraulic connection to the recordings (18) of the main housing (14). Pump housing according to one of the preceding claims, characterized in that the drive shaft bearing is formed in the main housing (14). Radial piston fuel pump with a pump housing according to one of the preceding claims, in which several, for example three, pumping units (6) are included. Pump housing according to claim 1 or 2, characterized in that that the pressure valve 46 at the crossing point between the pressure channel (56) and the pressure channel (58) is arranged.

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