DEVICE FOR MOUNTING A METAL RING FOR HARDNESS MEASUREMENTS

Abstract

A device for positioning a steel ring (12, 20) having a series of holes (14) distributed around its circumference, for performing hardness measurements on its outer surface by means of a system which exerts a force perpendicular to the surface via a punch (24). This device comprises a support including a hub (6) that fits into the ring (12, 20), having an upper positioning surface (8) for the inner contour of the ring, having tenons (10) that fit into holes in the ring (14) to achieve its positioning. Figure 1

Description

Title of the invention: DEVICE FOR MOUNTING A METAL RING FOR HARDNESS MEASUREMENTS

[0001] The present invention relates to a device for mounting a metal ring to perform hardness measurements on its outer contour, as well as a hardness measurement station equipped with such a device and an assembly comprising this device and a ring.

[0002] For the mass production of steel mechanical parts undergoing machining and heat treatment to achieve hardness, it is generally planned to periodically take a sample to measure this hardness in order to monitor the stability of the manufacturing process. Particularly in the automotive industry, powertrain transmission components subjected to high stresses require strict adherence to the production specifications for these components.

[0003] In particular, tests of the "Vickers" or "Rockwell" type can be carried out which vertically apply a penetrator forming a punch comprising a point or a ball to a horizontal surface of the material, with a calibrated force to measure the penetration of this element into the material in order to deduce its hardness.

[0004] A type of material hardness measuring station placed on a work surface, as described in particular by document DE-A1-2726867, comprises two adhesive supports spaced on this surface, using, for example, adhesive or a magnet, which are connected to each other by a crossbar. The connections between the crossbar and the supports include ball joints allowing pivoting, a slide in the horizontal plane for one of the connections, and for the other connection, fine adjustment of displacement in this plane with a micrometer screw.

[0005] A hardness measuring system having a vertical axis, fixed in the middle of the crossbar, includes a lower tip that receives a vertical force applied to the material to perform the measurement. Adjusting the crossbar's displacement allows the vertical axis of the measuring system to be precisely positioned to align with the exact point to be measured.

[0006] However, in the case of annular rings, with a vertical measurement to be taken on the outer contour of the ring arranged with a horizontal axis, this type of known measuring station does not allow the rings to be held in order to obtain both precise positioning, perpendicularity of the support on the surface, and a support forming a reaction to receive the load of the tip of the measuring system, just below this surface to avoid deformation of the ring.

[0007] The operator can hold the ring with one hand, leaving only one hand free to perform the measurement, which is impractical and time-consuming. Furthermore, the positioning of the measuring tip on the ring is not precise, and measurement variations may occur.

[0008] Furthermore, the operator's safety is not ensured by keeping a hand on the ring to hold it in place; in the event of slippage or failure of a component, the operator could be injured. Moreover, slippage of the ring risks damaging the penetrator applying the force, resulting in downtime for replacement and replenishment, and additional costs.

[0009] The present invention is specifically intended to avoid these problems of the prior art.

[0010] To this end, it proposes a device for mounting a metal ring having a series of holes distributed around its perimeter, to carry out hardness measurements on its outer surface by a system which exerts a force perpendicular to the surface by means of a punch, this device being remarkable in that it includes a support comprising a hub fitting into the ring, presenting a superior surface for resting the inner contour of the ring, having tenons which fit into holes in the ring by positioning it.

[0011] An advantage of this setting device is that, quickly, by simply removing the ring and adjusting the tenons in the holes which provide axial and angular positioning of this ring, a position of the ring is obtained under the axis of the punch with a constant precision which provides repeatability of the measurement.

[0012] The force applied by the punch is then directly absorbed by the upper surface of the fixture, which has two tenons. This surface receives the support of the inner contour of the ring, thus forming the reaction force directly under this load, without risk of elastic deformation of the ring. Furthermore, the ring is held securely and cannot slip, which prevents any risk of accidents.

[0013] The positioning device according to the invention may further comprise one or more of the following characteristics, which may be combined with each other.

[0014] Advantageously, the upper mounting surface has a curvature adjusted to that of the inner contour of the ring.

[0015] Advantageously, the two tenons fitted into two contiguous holes in the ring have a spacing corresponding to the width of the connection between these holes.

[0016] Advantageously, in its mounting position the ring has a transverse face in contact with a surface of the support which achieves an orientation of this ring.

[0017] Advantageously, each tenon is formed by a cylindrical pin tightened in a bore in the upper mounting surface.

[0018] In addition, the mounting device may comprise two upper surfaces of poses arranged in opposition on each side of a transverse partition, presenting two different geometries.

[0019] In this case, the two geometries can correspond to two ring diameters that are different.

[0020] Advantageously, one end of the base of the mounting device has a horizontal stop screw which is adjustable.

[0021] The invention also relates to a measuring station equipped with a positioning device with an adjustable stop screw, comprising a work surface supporting this device including a rear stop receiving the support of the adjustable screw.

[0022] The invention further relates to an assembly comprising a mounting device including any one of the preceding characteristics and a measured ring, remarkable in that the ring is part of an articulated wheel transmission joint of a motor vehicle.

[0023] The invention will be better understood and other features and advantages will become more apparent upon reading the following description given by way of example, with reference to the accompanying drawings in which:

[0024] [Fig-1] is a view of a positioning device according to the invention comprising two em placements for two different rings; and

[0025] [Fig.2] is a top view diagram showing the installation of this device on a measuring station.

[0026] Fig. 1 presents a highly rigid mounting device, comprising a rectangular base 2 elongated along a longitudinal direction, including in the middle along the length a transverse partition 4 receiving on one side a ring of small diameter 12 and on the other side a ring of large diameter 20, these rings being aligned along the same axis A arranged longitudinally with respect to the length of the base 2.

[0027] Each end of the base 2 along the longitudinal direction has in the middle of its transverse face an axial adjustment end screw 22 that can be adjusted and locked at a predefined length.

[0028] Each ring 12, 20, having spherical outer and inner surfaces centered on the same point on axis A, has on its contour, in a median transverse plane, a series of elongated holes in this plane, each designed to receive a drive ball for a constant velocity joint of a transmission forming a wheel shaft of a motor vehicle. The balls are fitted into grooves arranged along axial planes of an inner and an outer portion surrounding the ring, to allow articulation between these two portions with rotational drive provided by the balls.

[0029] The rings 12, 20 are made of steel that has undergone heat treatments to obtain a hardness that can withstand stress and wear, which must be checked by periodic sampling on the production line.

[0030] The transverse partition of the assembly 4 receives on each side a hub 6 arranged along the axis A, having an upper reaction surface 8 forming a portion of a sphere centered on this axis, which corresponds to the radius of the inner sphere of each ring 12, 20.

[0031] Each ring 12, 20 has on its upper surface 8 two tenons, each formed by a cylindrical pin 10 arranged vertically, aligned in a transverse plane, with a spacing corresponding to the width of the connection between two holes 14 in the corresponding ring. The pins 10, pressed into holes in the hub 6, economically form the tenons.

[0032] In this way, an operator can easily and quickly place a ring 12, 20 on the corresponding hub 6, on the upper surface 8, by inserting the part between two holes 14 into the space between the two pins 10. In this positioning, the rear transverse face of the ring 12, 20 rests on the surface 16 of the transverse partition 4, which confirms the axial and angular position of this ring, which has an axis precisely aligned with that of the hub 6.

[0033] The [Fig.2] presents a horizontal work surface supporting a measuring station comprising two lateral guides 30 receiving in a fitted manner the base of the positioning device 2 to adjust its transverse positioning, and a rear stop 32 receiving the support of one of the end screws 22 which has been adjusted previously to obtain along the axis A the positioning of the punch 24 relative to the ring 12, 20 receiving it.

[0034] By preparing the two axial adjustment screws 22 of the setting device for each of the corresponding rings 12, 20, the operator can simply and quickly place a ring on one side of the device, and slide this device on the work surface between the lateral guides 30 up to the rear stop 32 to automatically obtain a positioning of the punch 24 which is precisely in the median plane of the ring 12, 20, between two holes 14.

[0035] In addition, the axis of the punch 24, which includes a cone or a ball, is strictly perpendicular to the bearing surface, and the support hub 6 receives support from the inside of the ring directly under the punch with a corresponding surface, which ensures a rigid reaction under the force F, avoiding the addition of an intermediate elasticity which would disturb the measurement.

[0036] During the measurement, the ring 12, 20, wedged in all directions, cannot move, which prevents any slippage of the punch 24, and the risk of damage to this punch as well as accidents involving personnel.

Claims

Claims

1. Device for fitting a steel ring (12, 20) having a series of holes (14) distributed over its contour, for carrying out hardness measurements on its external surface by a system which exerts by a punch (24) a force perpendicular to the surface, characterized in that it comprises a support comprising a hub (6) entering into the ring (12, 20), having an upper surface (8) for fitting the internal contour of the ring (12, 20), having tenons (10) which fit into holes in the ring (14) while carrying out its positioning.

2. A laying device according to claim 1, characterized in that the upper laying surface (8) has a curvature adjusted to that of the inner contour of the ring (12, 20).

3. A fitting device according to any one of the preceding claims, characterized in that the two tenons (10) fitted into two contiguous holes in the ring (14) have a spacing corresponding to the width of the connection between these holes (14).

4. Laying device according to any one of the preceding claims, characterized in that in its laying position the ring (12, 20) has a transverse face bearing on a surface of the support (16) which provides an orientation of this ring.

5. A laying device according to any one of the preceding claims, characterized in that each tenon (10) is formed by a cylindrical pin clamped in a bore in the upper laying surface (8).

6. Laying device according to any one of the preceding claims, characterized in that it comprises two upper laying surfaces (8) arranged opposite each other on each side of a transverse partition (4), having two different geometries.

7. Laying device according to claim 6, characterized in that the two geometries correspond to two ring diameters (12, 20) which are different.

8. A setting device according to any one of the preceding claims, characterized in that one end of the base (2) of the setting device comprises a horizontal stop screw which is adjustable (22).

9. Measuring station equipped with a laying device according to claim 8, characterized in that it comprises a work surface supporting this laying device, comprising a rear stop (32) receiving the support of the adjustable screw (22).

10. An assembly comprising a fitting device according to any one of claims 1 to 8 and a measured ring (12, 20), characterized in that the ring is part of an articulated joint for the transmission of a motor vehicle wheel.

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