GB2039329A

GB2039329A - Rotary positive-displacement fluid-machines

Info

Publication number: GB2039329A
Application number: GB7942639A
Authority: GB
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1979-01-11
Filing date: 1979-12-11
Publication date: 1980-08-06
Also published as: GB2039329B; DE7900591U1; IT1130217B; IT8019117A0

Abstract

In a method of making a gear pump, or motor, comprising a pair of externally-toothed gear-wheels in intersecting bores 14, 16, when the bores have been made two troublesome wedge-shaped bodies 17 remain in the central portion of the housing 10 at the plane of intersection of the bores, both of these bodies being removed by cutting a third bore 15. At least on the high-pressure side of the gears wedge- shaped filling members 34(35) are positioned between the sides of the gear- wheels and the end walls of the housing to obviate leakage. Pressure-loaded axial-sealing plates (37,38) may be provided. <IMAGE>

Description

SPECIFICATION A gear pump or motor The invention relates to a method of making a gear machine (pump or motor) and to a gear machine made by the method.

Gear machines usually comprise gear wheels meshing in external engagement arranged in intersecting bores in the housing of the machine. The forming of the intersecting bores produces two wedges coming to a point at the intersection of the two bores, in the central plane of the housing. These wedges lead to manufacturing problems due to their angles terminating in sharp edges.

The method in accordance with the invention, of making a gear machine (pump or motor) having gear wheels meshing in external engagement in the interior of the machine housing, includes the steps of producing two intersecting bores in the housing for accommodating the meshing gear wheels, removing the wedges of material produced at the intersection of the intersecting bores by means of a third bore and replacing at least the thus removed wedge on the high pressure side of the gear machine by filling members of corresponding shape and which are positioned between the side of the gear wheels and the end walls of the housing.

The advantage of that method is that less difficulties arise during manufacture of the machine than before.

Preferably, the third bore is made of substantially the same diameter as the two intersecting bores.

The invention also extends to a gear machine (pump or motor) made in accordance with that method.

Each filling member may extend between and to the faces of the gearwheels at one side thereof and an end wall of the housing. Alternatively, when the gear machine comprises bearing members accommodating shafts for the gear wheels and sealing plates arranged between the bearing members and the sides of the gear wheels, each filling member may extend between and to a sealing plate and an end wall of the housing.

Seals may also be arranged at the sealing plates.

When the gear machine is operating, these seals bound pressure fields which urge the sealing plates against the sides of the gear wheels. In that case, the seals and the filling members may be made integral with one another if they are made of the same material such as metal or a synthetic plastics material.

In order that the invention may be well understood, there will now be described an embodiment thereof, given by way of example, reference being had to the accompanying drawings, in which: Figure lisa cross-section through a gear machine taken on the line I-I of Figure 2; Figure 2 is a cross-section taken on the line Il-Il of Figure 1; and Figure 3 is a longitudinal section taken on the line III-ill of Figure 1.

The gear machine has a housing 10 which is closed at both ends by covers 11 and 12. The interior 13 of the housing is formed by three intersecting bores 14,15 and 16. In so doing, substantially the shape of an eight with a straight centre exists in cross-section.

This straightening is produced by the bore 15 which lies in the centre between the two bores 14 and 16, the spacing of which is so calculated that they also intersect in the centre. Until the third bore 15 is made, wedge-shaped regions are produced by the intersecting bores 14, 16, one of which regions is referenced 17 in the drawing. Because of the very sharp angle of the wedge lying in the centre of the housing, manufacturing problems resulted previously due to the formation of flash at the point of the wedge. This is avoided by the additional bore 15 which is preferably of substantially the same diameter as the bores 14 and 16 and by means of which the points of the wedges are eliminated.

Gear wheels 19 and 20 are arranged in the thus formed interior 13 of the housing, the journals 21,22 and 23,24 of the gear wheels being mounted in bearing members 25,26 and 27, 28 which are also located in the interior of the housing. The gear wheel 20 has a shaft extension 30 which passes through a bore 31 in the cover 12 and serves for driving the gear machine. A seal 32 is also arranged at that location.

What is then necessary, is that the cavity between the housing wall and the gear wheels produced by the bore 15 is filled, at least on the high pressure side - which is referenced 33. This is provided with the aid of two filling members 34 and 35 which are of exactly the same shape as the wedge 17 formed as described above, each filling member extending between faces of the gear wheels at one side thereof and an end wall of the housing. Such filling members are not required on the low pressure side - this is referenced 36 - but they can be provided if that is necessary.

The gear machine is also provided with sealing plates 37 and 38 which are arranged between the side surfaces of the gear wheels and the bearing members. Against these, pressure fields (not referenced) are formed by seals 39,40 bounding the pressure fields and arranged at the sealing plates 37 and 38 which urge the side plates sealingly against the sides of the gear wheels. Thus, in this case, the filling members 34,35 extend from the covers 11 and 12 up to the sealing plates 37 and 38. In gear machines without such sealing plates, the filling members 34 and 35 extend right up to the sides of the gear wheels.

The filling members may be made of metal or a synthetic plastics material. When the seals consist of the same material as the filling members they can be made integral with the filling members.

1. A method of making a gear machine (pump or motor) having gear wheels meshing in external engagement in the interior of the machine housing, said method including the steps of producing two intersecting bores in the housing for accommodating the meshing gear wheels, removing the wedges

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION A gear pump or motor The invention relates to a method of making a gear machine (pump or motor) and to a gear machine made by the method. Gear machines usually comprise gear wheels meshing in external engagement arranged in intersecting bores in the housing of the machine. The forming of the intersecting bores produces two wedges coming to a point at the intersection of the two bores, in the central plane of the housing. These wedges lead to manufacturing problems due to their angles terminating in sharp edges. The method in accordance with the invention, of making a gear machine (pump or motor) having gear wheels meshing in external engagement in the interior of the machine housing, includes the steps of producing two intersecting bores in the housing for accommodating the meshing gear wheels, removing the wedges of material produced at the intersection of the intersecting bores by means of a third bore and replacing at least the thus removed wedge on the high pressure side of the gear machine by filling members of corresponding shape and which are positioned between the side of the gear wheels and the end walls of the housing. The advantage of that method is that less difficulties arise during manufacture of the machine than before. Preferably, the third bore is made of substantially the same diameter as the two intersecting bores. The invention also extends to a gear machine (pump or motor) made in accordance with that method. Each filling member may extend between and to the faces of the gearwheels at one side thereof and an end wall of the housing. Alternatively, when the gear machine comprises bearing members accommodating shafts for the gear wheels and sealing plates arranged between the bearing members and the sides of the gear wheels, each filling member may extend between and to a sealing plate and an end wall of the housing. Seals may also be arranged at the sealing plates. When the gear machine is operating, these seals bound pressure fields which urge the sealing plates against the sides of the gear wheels. In that case, the seals and the filling members may be made integral with one another if they are made of the same material such as metal or a synthetic plastics material. In order that the invention may be well understood, there will now be described an embodiment thereof, given by way of example, reference being had to the accompanying drawings, in which: Figure lisa cross-section through a gear machine taken on the line I-I of Figure 2; Figure 2 is a cross-section taken on the line Il-Il of Figure 1; and Figure 3 is a longitudinal section taken on the line III-ill of Figure 1. The gear machine has a housing 10 which is closed at both ends by covers 11 and 12. The interior 13 of the housing is formed by three intersecting bores 14,15 and 16. In so doing, substantially the shape of an eight with a straight centre exists in cross-section. This straightening is produced by the bore 15 which lies in the centre between the two bores 14 and 16, the spacing of which is so calculated that they also intersect in the centre. Until the third bore 15 is made, wedge-shaped regions are produced by the intersecting bores 14, 16, one of which regions is referenced 17 in the drawing. Because of the very sharp angle of the wedge lying in the centre of the housing, manufacturing problems resulted previously due to the formation of flash at the point of the wedge. This is avoided by the additional bore 15 which is preferably of substantially the same diameter as the bores 14 and 16 and by means of which the points of the wedges are eliminated. Gear wheels 19 and 20 are arranged in the thus formed interior 13 of the housing, the journals 21,22 and 23,24 of the gear wheels being mounted in bearing members 25,26 and 27, 28 which are also located in the interior of the housing. The gear wheel 20 has a shaft extension 30 which passes through a bore 31 in the cover 12 and serves for driving the gear machine. A seal 32 is also arranged at that location. What is then necessary, is that the cavity between the housing wall and the gear wheels produced by the bore 15 is filled, at least on the high pressure side - which is referenced 33. This is provided with the aid of two filling members 34 and 35 which are of exactly the same shape as the wedge 17 formed as described above, each filling member extending between faces of the gear wheels at one side thereof and an end wall of the housing. Such filling members are not required on the low pressure side - this is referenced 36 - but they can be provided if that is necessary. The gear machine is also provided with sealing plates 37 and 38 which are arranged between the side surfaces of the gear wheels and the bearing members. Against these, pressure fields (not referenced) are formed by seals 39,40 bounding the pressure fields and arranged at the sealing plates 37 and 38 which urge the side plates sealingly against the sides of the gear wheels. Thus, in this case, the filling members 34,35 extend from the covers 11 and 12 up to the sealing plates 37 and 38. In gear machines without such sealing plates, the filling members 34 and 35 extend right up to the sides of the gear wheels. The filling members may be made of metal or a synthetic plastics material. When the seals consist of the same material as the filling members they can be made integral with the filling members. CLAIMS

1. A method of making a gear machine (pump or motor) having gear wheels meshing in external engagement in the interior of the machine housing, said method including the steps of producing two intersecting bores in the housing for accommodating the meshing gear wheels, removing the wedges of material produced at the intersection of the intersecting bores by means of a third bore and replacing at least the thus removed wedge on the high pressure side of the gear machine by filling members of corresponding shape and which are positioned between the sides of the gear wheels and the end walls of the housing.

2. A method according to claim 1, wherein the third bore is of substantially the same diameter as the two intersecting bores.

3. A gear machine (pump or motor) made in accordance with the method of claim 1 or claim 2.

4. A gear machine according to claim 3, in which each filling member extends between and to the faces of the gear wheels at one side thereof and an end wall of the housing.

5. A gear machine according to claim 3, comprising bearing members accommodating shafts for the gear wheels, sealing plates being arranged between the bearing members and the sides of the gear wheels, each filling member extending between and to a sealing plate and an end wall of the housing.

6. A gear machine according to claim 5, in which seals bounding pressure fields are arranged at the sealing plates, each filling member being integral with one of the seals.

7. A gear machine according to any one of claims 3 to 6, in which the filling members are of metal or a synthetic plastics material.

8. A gear machine (pump or motor) substantially as herein described with reference to the accompanying drawings.

9. A method of making a gear machine (pump or motor) substantially as herein described with reference to the accompanying drawings.