EP1433546A1 - Production method and device for producing an annular container for an electric winding for assembly to a pulley of a motor vehicle air conditioning system - Google Patents

Abstract

There is described a production method for producing an annular container (12) for an electric winding for assembly to a motor vehicle air conditioning system pulley, wherein the annular container (12) is produced from a flat washer (11) in one forming operation.

Description

The present invention relates to a production method and device for producing an annular container for an electric winding for assembly to a pulley of a motor vehicle air conditioning system.

As is known, the compressor of a motor vehicle air conditioning system is powered by the vehicle engine via a normally belt and pulley type drive assembly.

As is also known, as a result of stricter regulations governing exhaust gas emissions by motor vehicles, vehicles have been designed in which the engine turns itself off whenever the vehicle stops temporarily, e.g. at a traffic light or in a queue, and is turned back on automatically when a specific command is imparted to the vehicle, e.g. when the clutch pedal is pressed.

In this type of vehicle, in which the engine is stopped more frequently than in conventional vehicles, to ensure continuous operation of the air conditioning system when the engine is temporarily turned off, the air conditioning system is powered by an auxiliary electric motor powered by the vehicle battery.

Selective connection of the air conditioning system compressor to the vehicle engine or auxiliary motor is made by means of an electromagnetic clutch controlled by the electronic central control unit on the vehicle according to whether the vehicle engine is on or off.

The electromagnetic clutch comprises, among other things, an electric winding for generating the electromagnetic field required to perform the above selective connection function, and which is normally housed inside an annular container fitted to the hub of the drive assembly pulley connected to the air conditioning system compressor.

At present, the annular container is stamped from a flat washer in a series of successive forming operations, by which the flat washer gradually assumes the desired final shape of the annular container.

To prevent breakage of the annular container during production, the forming operations are normally performed at intervals sufficient to allow the material to stabilize between one operation and the next, so that current production methods involve a good deal of time and work.

It is an object of the present invention to provide a production method and device for producing a container of the type described in less time than that required by known production methods.

According to the present invention, there is provided a production method and device for producing an annular container for an electric winding for assembly to a motor vehicle air conditioning system pulley, as claimed in Claims 1 and 6 respectively.

A preferred, non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which:

Figure 1 shows a die for producing a container for an electric winding for assembly to a motor vehicle air conditioning system pulley in accordance with the present invention and in a first operating configuration;

Figure 2 shows the Figure 1 die in a second operating configuration;

Figure 3 shows a cross section of an annular forming cavity of the Figure 1 and 2 die in accordance with a preferred embodiment of the invention.

Number 1 in Figures 1 and 2 indicates as a whole a die in accordance with the present invention for producing an annular container for an electric winding for assembly to a pulley of a motor vehicle air conditioning system (not shown). More specifically, Figures 1 and 2 only show the parts of the die pertinent to a clear understanding of the present invention.

Die 1 substantially comprises a fixed half-die 2; a movable half-die 3 facing fixed half-die 2 and cooperating, in use, with it in a mating direction indicated by arrow F; and an actuating assembly (not shown) for moving movable half-die 3, in mating direction F, between an open position (Figure 1) in which movable half-die 3 is detached from fixed half-die 2, and a closed position (Figure 2) in which movable half-die 3 cooperates with fixed half-die 2.

Fixed half-die 2 substantially comprises a base 4; and a matrix 5 projecting integrally from base 4 and defining an annular forming cavity 6 open towards both movable half-die 3 and base 4.

More specifically, annular forming cavity 6 is substantially cylindrical with an axis A coincident with mating direction F, tapers towards the end opposite the end facing movable half-die 3, and is defined laterally by smooth surfaces.

Movable half-die 3 substantially comprises a supporting wall 7; and a punch 8 projecting integrally from supporting wall 7, extending coaxially with axis A towards the matrix of fixed half-die 2, and complementary in shape to annular forming cavity 6, so as to be insertable inside annular forming cavity 6 with very little radial clearance as movable half-die 3 is moved towards fixed half-die 2 in mating direction F.

Die 1 also comprises an extractor 9 for extracting the finished annular container from matrix 5. More specifically, extractor 9 is fitted to base 4 of fixed half-die 2, on the opposite side to matrix 5, and is substantially defined by an annular punch 10 coaxial with axis A and movable, in use, in mating direction F in the opposite sense to that of punch 8 of movable half-die 3, so as to be insertable inside annular forming cavity 6, through the opening opposite that through which punch 8 of movable half-die 3 acts, to push the finished annular container out of matrix 5.

In actual use, the annular container is produced in one forming operation, i.e. in one operation of die 1. More specifically, after placing a flat washer 11 (Figure 1) on matrix 5 of fixed half-die 2, over the opening of annular forming cavity 6 facing movable half-die 3, movable half-die 3 is operated and, as it moves towards fixed half-die 2, causes flat washer 11 to gradually assume the desired final shape of the annular container 12 (Figure 2), - in this case, a U-section annular container.

Once annular container 12 is formed, extractor 9 is operated to push annular container 12 out of annular forming cavity 6.

Figure 3 shows a different embodiment of the present invention, which has proved particularly effective in the event the specific application calls for an annular container 12 with particularly thin lateral walls.

More specifically, as shown in Figure 3, for this type of application, annular forming cavity 6 of matrix 5 of fixed half-die 2 is defined laterally by surfaces undulated in mating direction F, as opposed to smooth surfaces.

Tests have shown that, with this particular design of the lateral walls of annular forming cavity 6, the material is practically only drawn at the grooves of the undulations, whereas, at the ridges, the material undergoes a stabilizing effect, which provides for locally controlling deformation of the material when producing annular container 12, and so greatly reducing breakage of annular container 12.

The advantages of the present invention will be clear from the foregoing description.

In particular, by producing the annular container in one forming operation, and so eliminating the material stabilizing intervals between successive forming operations typical of known production methods, the annular container is produced much faster as compared with known production methods, with obvious benefits in terms of the cost of the annular container itself.

Clearly, changes may be made to the method and device as described and illustrated herein without, however, departing from the scope of the present invention as defined in the accompanying Claims.

Claims (9)

1. A production method for producing an annular container (12) for an electric winding for assembly to a motor vehicle air conditioning system pulley, characterized in that said annular container (12) is produced from a flat washer (11) in one forming operation.
2. A production method as claimed in Claim 1, characterized by comprising the steps of:

   providing a die (1) comprising a fixed half-die (2), and a movable half-die (3) cooperating, in use, with said fixed half-die (2) in a mating direction (F);

   forming, in said fixed half-die (2), an annular forming cavity (6) open towards said movable half-die (3) ;

   placing said flat washer (11) over the opening of said annular forming cavity (6); and

   activating said movable half-die (3) to form said annular container (12) in one operation.
3. A production method as claimed in Claim 2, characterized in that said annular forming cavity (6) is substantially cylindrical with an axis (A) extending in said mating direction (F), and tapers towards the end opposite the end facing said movable half-die (3).
4. A production method as claimed in Claim 3, characterized in that said annular forming cavity (6) is defined laterally by smooth walls.
5. A production method as claimed in Claim 3,
   characterized in that said annular forming cavity (6) is defined laterally by walls undulated in said mating direction (F).
6. A production device (1) for producing an annular container (12) for an electric winding for assembly to a motor vehicle air conditioning system pulley; said production device (1) comprising a fixed half-die (2), and a movable half-die (3) cooperating, in use, with said fixed half-die (2) in a mating direction (F); said fixed half-die (2) comprising a matrix (5) defining an annular forming cavity (6) open towards said movable half-die (3) and over which a flat washer (11) is placed in use; and said production device (1) being characterized in that said annular container (12) is produced from said flat washer (11) in one operation of said movable half-die (3) .
7. A production device as claimed in Claim 6, characterized in that said annular forming cavity (6) is substantially cylindrical with an axis (A) extending in said mating direction (F), and tapers towards the end opposite the end facing said movable half-die (3).
8. A production device as claimed in Claim 7, characterized in that said annular forming cavity (6) is defined laterally by smooth walls.
9. A production device as claimed in Claim 7, characterized in that said annular forming cavity (6) is defined laterally by walls undulated in said mating direction (F).

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