GB2151163A

GB2151163A - Treatment of workpieces

Info

Publication number: GB2151163A
Application number: GB08429195A
Authority: GB
Inventors: Arthur Martin
Original assignee: Georg Fischer AG
Current assignee: Georg Fischer AG
Priority date: 1983-11-25
Filing date: 1984-11-19
Publication date: 1985-07-17
Also published as: GB8429195D0; ES292973Y; IT8423720A0; IT8423720A1; PT79521A; PT79521B; DE3440780A1; IT1177311B; FR2555704A1; ES292973U

Abstract

A workpiece, such as a cast housing (1) of a differential gear, made of cast iron, is treated in which the structural design of the desired form is such that the areas to be treated, e.g. apertures 3-7, can be determined with respect to a treatment axis (A) common to all the areas requiring treatment. Thereby, all the areas to be treated can be combined into one operation. By excluding the requirement for different treatment operations, as in known techniques, workpieces according to the invention can be produced more economically. <IMAGE>

Description

SPECIFICATION The treatment of workpieces This invention relates to the treatment of workpieces, and particularly, though not exclusively, workpieces of cast iron materials, with surface areas to be treated which have, for example, seams, deadheads etc.

It is known to produce workpieces, such as housings, for example for differential gears, of cast iron materials, whereby shape deviations conditional on the casting technique must be accepted. What is meant by shape deviations are for example seams, gates or tolerance-caused deviations in the production of the shapes, but also the roughness of the surface.

In order to free a casting of these shape deviations, up till now a series of different subsequent processes have had to be carried out, like turning, stamping, milling, grinding or boring, which all required another machine or work station and passage through many hands, which made the finished product substantially more expensive.

The invention has been developed primarily with a view to eliminate these disadvantages and structurally to so design castings of this type that the (coarse) treatment can take place in a single operation.

According to the invention there is provided a workpiece having predetermined surface regions which require treatment, said regions being defined with respect to a treatment axis which is common to all of the regions.

The invention will now be described in detail, by way of example only, with reference to the accompanying drawing, in which: Figure 1 is a front view of a workpiece according to the invention in the form of a differential gear housing; and Figure 2 is a plan view of the housing in the direction of the arrow I.

Referring now to the drawing, Figure 1 shows the box or housing 1 of a differential gear, which has on its underside a flange 2 for connecting to a crown wheel (not shown). The securing to the crown wheel is by fasteners taken through screw holes 3 which are arranged along the circumference of the flange 2. The housing 1 has two sleeve bearings 4 and 5 for the shafts (and bevel gear wheels) of the drive wheels of a motor vehicle (so called half-shafts), and two bearing apertures 6 and 7 arranged transversely thereto, which are intended for throughgoing bearing pins for two bevel-gear wheels (differential pinions), not shown.On one axis which is vertical on the drawing surface there are arranged two assembly apertures 8 lying one behind the other in the line of sight, which on the one hand make possible access to the inside of the housing when the bevel-gear wheels are being assembled, and on the other hand are used for lubrication.

The outer contour 10 of the housing 1 is structurally so designed that all areas which have to be subjected to a coarse subsequent treatment, like the flange 2, the thickenings 9 which carry the bearing apertures 6 and 7 and are restricted to two relatively small circumferential areas offset to one another by 1800, the edges of both assembly apertures 8, and the bearing sleeves 4 and 5, are arranged with respect to a common axis of movement A so that each area to be individually treated can be determined and reached from the axis A.

Figure 2 shows the same housing in the direction of the arrow I in Figure 1. The flange 2 can be distinguished with screw holes for securing the crown wheel to the drive of the housing by means of a gear wheel, which flange is trued on its outer surface and on the upwardly-directed surface of Figure 1,so as to obtain a clean surface onto which the crown wheel can be placed flush.

The references 12 and 13 designate the edges of the assembly apertures in corresponding projection.

The two thicknesses 9, which reach approximately to half the height of the housing 1, run parallel to the axis A over the largest part of its height. However, in the circumferential direction the thicknesses are curved and with a radius R which goes from the centre point M of the axis A.

The embodiment of workpiece described above is a differential gear housing. However, it should be understood that a treatment method according to the invention, and a workpiece according to the invention which requires treatment, may respectively be applied to, or may be castings or other workpieces (not necessarily of cast iron). Such castings or other workpieces must have at least partially axially symmetrical shapes, or can be inserted at least into an imaginary axially symmetrical casing.

Accordingly, there is disclosed herein the treatment of a workpiece (1), preferably of cast iron material, which has surface areas to be treated, wherein the structural design of the desired form is such that the areas to be treated (2,9,8,4, and 5) can be determined or defined with respect to a treatment axis (A) common to all the areas to be treated. Thereby, all the areas to be treated can be combined into a single operation. By the exclusion of the necessity for different treatment operations, as in known techniques, workpieces according to the invention, and treated by a method according to the invention, may be produced more ecomically than hitherto.

1. A workpiece having predetermined surface regions which require treatment, said regions being defined with respect to a treatment axis which is common to all of the regions.

2. A workpiece according to claim 1, in which the surface regions can be gripped in a machining operation.

3. A workpiece according to claim 1 or 2, and taking the form of a housing or box of a differential gear.

4. A workpiece according to claim 3, in which the differential housing comprises two assembly apertures having seams and two axle bearings also having seams which require treatment, the assembly apertures and the axle bearing being

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

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION The treatment of workpieces This invention relates to the treatment of workpieces, and particularly, though not exclusively, workpieces of cast iron materials, with surface areas to be treated which have, for example, seams, deadheads etc. It is known to produce workpieces, such as housings, for example for differential gears, of cast iron materials, whereby shape deviations conditional on the casting technique must be accepted. What is meant by shape deviations are for example seams, gates or tolerance-caused deviations in the production of the shapes, but also the roughness of the surface. In order to free a casting of these shape deviations, up till now a series of different subsequent processes have had to be carried out, like turning, stamping, milling, grinding or boring, which all required another machine or work station and passage through many hands, which made the finished product substantially more expensive. The invention has been developed primarily with a view to eliminate these disadvantages and structurally to so design castings of this type that the (coarse) treatment can take place in a single operation. According to the invention there is provided a workpiece having predetermined surface regions which require treatment, said regions being defined with respect to a treatment axis which is common to all of the regions. The invention will now be described in detail, by way of example only, with reference to the accompanying drawing, in which: Figure 1 is a front view of a workpiece according to the invention in the form of a differential gear housing; and Figure 2 is a plan view of the housing in the direction of the arrow I. Referring now to the drawing, Figure 1 shows the box or housing 1 of a differential gear, which has on its underside a flange 2 for connecting to a crown wheel (not shown). The securing to the crown wheel is by fasteners taken through screw holes 3 which are arranged along the circumference of the flange 2. The housing 1 has two sleeve bearings 4 and 5 for the shafts (and bevel gear wheels) of the drive wheels of a motor vehicle (so called half-shafts), and two bearing apertures 6 and 7 arranged transversely thereto, which are intended for throughgoing bearing pins for two bevel-gear wheels (differential pinions), not shown.On one axis which is vertical on the drawing surface there are arranged two assembly apertures 8 lying one behind the other in the line of sight, which on the one hand make possible access to the inside of the housing when the bevel-gear wheels are being assembled, and on the other hand are used for lubrication. The outer contour 10 of the housing 1 is structurally so designed that all areas which have to be subjected to a coarse subsequent treatment, like the flange 2, the thickenings 9 which carry the bearing apertures 6 and 7 and are restricted to two relatively small circumferential areas offset to one another by 1800, the edges of both assembly apertures 8, and the bearing sleeves 4 and 5, are arranged with respect to a common axis of movement A so that each area to be individually treated can be determined and reached from the axis A. Figure 2 shows the same housing in the direction of the arrow I in Figure 1. The flange 2 can be distinguished with screw holes for securing the crown wheel to the drive of the housing by means of a gear wheel, which flange is trued on its outer surface and on the upwardly-directed surface of Figure 1,so as to obtain a clean surface onto which the crown wheel can be placed flush. The references 12 and 13 designate the edges of the assembly apertures in corresponding projection. The two thicknesses 9, which reach approximately to half the height of the housing 1, run parallel to the axis A over the largest part of its height. However, in the circumferential direction the thicknesses are curved and with a radius R which goes from the centre point M of the axis A. The embodiment of workpiece described above is a differential gear housing. However, it should be understood that a treatment method according to the invention, and a workpiece according to the invention which requires treatment, may respectively be applied to, or may be castings or other workpieces (not necessarily of cast iron). Such castings or other workpieces must have at least partially axially symmetrical shapes, or can be inserted at least into an imaginary axially symmetrical casing. Accordingly, there is disclosed herein the treatment of a workpiece (1), preferably of cast iron material, which has surface areas to be treated, wherein the structural design of the desired form is such that the areas to be treated (2,9,8,4, and 5) can be determined or defined with respect to a treatment axis (A) common to all the areas to be treated. Thereby, all the areas to be treated can be combined into a single operation. By the exclusion of the necessity for different treatment operations, as in known techniques, workpieces according to the invention, and treated by a method according to the invention, may be produced more ecomically than hitherto. CLAIMS

4. A workpiece according to claim 3, in which the differential housing comprises two assembly apertures having seams and two axle bearings also having seams which require treatment, the assembly apertures and the axle bearing being arranged for treatment in a single operation whereby individual coarse and fine treatment phases can be combined.

5. A workpiece according to any one of the preceding claims and made of cast material.

6. Aworkpiece according to claim 5 and made of cast iron.

7. A workpiece according to any one of the preceding claims, in which the surface regions requiring treatment have seams, deadheads and the like.

8. Aworkpiece according to claim 1 and substantially as hereinbefore described with reference to, and as shown in the accompanying drawing.

9. A method of treating surface regions of a workpiece, in which at least some of the surface regions are arranged generally symmetrically about a common treatment axis, whereby the surface regions are defined in relation to this axis for a single treatment operation.