KR20090019710A - Systems and methods for staking part assemblies using corrections for part tolerances - Google Patents

Abstract

The novel methods and systems herein are provided for staking parts in a mechanical device to achieve a staked device having one or more good part-to-part gaps regardless of feedstock variations in the materials used to form the part. A variant is produced for at least one staking die of a pair of staking dies used in a staking press, and a variant having an appropriate staking gap is selected each time a group of parts changes. In this way, deformations between many of the feedstock materials used to form the part will not result in a staked device that suffers lateral looseness or other staking results that do not meet the design specification. In a second embodiment, the device is first dropped into a conventional staking press and then loaded into a gap setting press that deforms at least a portion of the staked device to obtain a good gap. By carefully limiting the force at which deformation is performed, a good gap can be obtained without requiring a group of parts in the fabrication process.

Description

System and method for staking a part assembly using compensation for part tolerances {SYSTEM AND METHOD FOR STAKING AN ASSEMBLY OF COMPONENTS WITH COMPENSATION FOR COMPONENT TOLERANCES}

The present invention relates to a system and method for staking an assembly of parts in a mechanical apparatus. In particular, the present invention relates to systems and methods by staking one or more parts in a mechanical device to other parts in the device such that the resulting looseness of the parts in the assembly device can be reduced regardless of tolerances in the assembly material. It is about.

It is known to make a device that is not expected to be disassembled by staking mechanical parts from each other from an assembly of mechanical parts. In general, one or more mechanical parts will include one or more parts ("staking material") that are permanently deformed during the staking process to secure the parts to each other (ie, "stake"). The compressing force of the staking process is applied to the assembly of mechanical parts through a pair of suitably shaped dies to secure the parts together to bend, twist and spread the mushrooms or otherwise permanently deform the device to form the device.

Staking is relatively inexpensive, in that it requires a small volume in the assembly (unlike bolts or screws that require a volume in the assembly to accommodate the threads of the bolt or screw) and results in permanent connection of the assembly into the device. It offers several advantages over other assembly techniques such as bolts or welding.

However, staking also has disadvantages. When the device is assembled by staking, despite the device housing being staked, tolerances of the parts in the staked device may result in some looseness of the parts in the device, preventing one or more parts from moving relative to the remaining parts. Allow. When subjected to mechanical vibrations, loose parts or parts can move and cause undesirable noise generated in the device. In particular, in the automotive industry, these noises are often referred to as Buzz, Squeak and Rettle ("BSR") and are very undesirable.

Existing attempts to reduce undesirable looseness by close tolerances on feedstock materials have resulted in unacceptable increases in manufacturing costs. Other attempts to mitigate signs of undesirable looseness, such as BSR, include additional elastic materials in the staked device, but these materials may also increase manufacturing costs and have a short lifespan that is unacceptable within the device.

It is desirable to have a method for staking an assembly of parts in a mechanical device that can avoid undesired looseness of the parts in the staked device.

It is an object of the present invention to provide a novel system and method for staking an assembly of components in a mechanical device that obviates or mitigates one or more disadvantages of the prior art.

According to a first aspect of the invention, the step (i) of forming one or more test devices utilizing a pair of staking dies in a press and one or more test devices to determine whether the gap between the components in the device has been properly achieved. (Ii) inspecting (i), if the gap is not properly achieved, (i) changing at least one staking die of the pair of staking dies in the press and restarting the method in step (iii); If the gap has been properly achieved, the steps of (i) creating the devices with a pair of staking dies, a group of changes in any part staked in the device, and the dimensional change in the changed part may affect the gap. If so, a method is provided for staking an assembly of parts in a mechanical device comprising the step (iii) restarting the method in step (iii). .

Preferably, step (iii) determines whether the gap of the one or more test apparatus is too large or too small, and if too small, changes at least one die of the pair of die to increase the gap of the die; Or changing at least one die of the pair of dies to reduce the gap of the die if too large.

According to another aspect of the invention, the steps of (iv) dropping parts into a staking press and staking the parts to form a staked device, and a portion of the device attached to and staked to the support and the ram on which the device is placed; (Ii) dropping the staked device into a gap setting press including a compression die operable to engage with and deforming a portion of the staked device to set a preselected gap; and moving the ram to move the preselected force. And (iii) deforming the portion of the staked apparatus to set the preselected clearance by bringing the compression die into contact with the portion of the staked apparatus. A method is provided for staking an assembly of parts in a mechanical device with a gap.

The present invention provides a new method of staking a part in a mechanical device to achieve a staked device having a gap between one or more good parts, regardless of feedstock changes in the material used to form the part. A variant is fabricated for at least one staking die of a pair of staking dies used in a staking press, and a variant having an appropriate staking gap is selected whenever a group of parts changes. In this way, a change between many of the feedstock materials used to form the part will not result in other staking results that do not meet the design specifications for the staked device or devices that suffer from lateral looseness. In a second embodiment, the device is first staked in a conventional staking press and then loaded into a gap setting press that deforms at least a portion of the staked device to obtain a good gap.

By carefully limiting the force that causes deformation to be performed, a good gap can be obtained without requiring a group of parts in the fabrication process.

The following description of the system and method of the present invention is made with reference to the staking of certain devices, specifically known disc recliners, as an example of an apparatus that can be advantageously fabricated with the system and method of the present invention. However, the present invention is not limited to use in manufacturing such disc recliners or any other particular apparatus. Instead, the present invention can be advantageously employed to manufacture a wide variety of devices as will be appreciated by those skilled in the art.

As described above, known disc recliners are generally referred to in FIG. 1 by reference numeral 20. Devices such as the disc recliner 20 are commonly employed to provide for positioning of the car seat back relative to the seat base.

As shown in the figure, the disc recliner 20 includes a guide plate 24 that can be attached to the seat base and a serrated plate 28 that can be attached to the seat back. A set of pawls 32 are positioned in the guide plate 24 and engage the guide plate 24 by engaging a set of teeth positioned around the inner lip of the toothed plate 28. It is biased by the spring 36 to fix the angular position of the serrated plate 28 relative to it. The shaft 40 includes a cam 44 positioned within a set of poles 32. Finally, the retainer ring 48 is staked on the guide plate 24 to surround other components of the disc recliner 20 to complete the assembly of the disc recliner 20.

If it is desired to change the position of the seat back relative to the seat base by changing the angular position of the serrated plate 28 relative to the guide plate 24, the lever (not shown) attached to the shaft 40 moves. It rotates the shaft 40 and causes the cam surface of the cam 44 to contact the set of poles 32.

The cam 44 moves the pawl 32 against contact with the teeth of the serrated plate 28 against the biasing force of the spring 36, which is between the serrated plate 28 and the guide plate 24. Allow relative angular shifts.

When the seat back is positioned as desired, the lever is released and the cam 44 allows a set of pawls 32 to engage the teeth of the toothed plate 28 again by the biasing force of the spring, thus guiding Reposition the angular position of the serrated plate 28 relative to the plate 24 and the seat back relative to the seat base.

As shown in FIG. 2, when the retainer ring 48 is staked to the guide plate 24, the serrated plate 28 is removed when a set of pawls 32 are separated from the serrated plate 28. In order to allow rotation about the guide plate 24 and the retainer ring 48, a gap 60 must be provided between the toothed plate 28 and the radially upper surface 64 of the retainer ring 48.

The gap 60 should be sufficient to allow rotation of the toothed plate 28, but if the gap is excessive, the toothed plate 28 may be capable of excessive movement within the disc recliner 20. As a result, undesirable BSR noise may be generated. Therefore, control of the gap 60 is important to allow for the correct operation of the disc recliner 20 while avoiding undesirable BSR noises.

As mentioned above, the present invention is not limited to the manufacture of the disc recliner 20 or the like, and many other staked devices have similar problems due to the gaps between the parts, and the present invention It can be advantageously employed in the manufacture of the device.

3 shows a staking press 100 used in the method according to the invention. Press 100 may be generally conventional, and base portion 104 also preferably includes a locator 112 that aids in loading and aligning the parts to which the lower die is attached and staked by the press 100. It is preferable to include.

In the illustrated embodiment, the disc recliner 20 is staked by the press 100, but various other devices may be staked in accordance with the present invention as mentioned above.

The press 100 further includes a ram 116 on which the upper die 120 is mounted, an example of the upper die 120 being well illustrated in FIGS. 5 and 6. When the upper die 120 contacts the lower die 108 as the press 100 cycles, the upper die 120 is appropriately shaped and volumed to receive the upper portion of the disc recliner device 20. Cavity 124 having a.

In the illustrated embodiment, which is very similar to many similar conventional staking operations, the guide plate 24 of the disc recliner device 20 is provided with a lower die (with the rest of the disc recliner 20 placed on top). 108). The press 100 is then closed with the retainer ring 48 being received in the cavity 24, and the lower edge of the retainer ring 48 at the lower side of the guide plate 24 as shown in FIGS. 2 and 4. The disc recliner device 20 stakes each other by engaging a lower die 108 that folds the lower edge over the edge and onto the edge of the lower side.

However, unlike known staking presses and methods, the upper die 120 retains the retainer ring 48 when the press 100 is closed such that the upper radial surface 64 is compressed downward to reduce the gap 60. It further comprises a first compression surface 136 and a second compression surface 132 to engage the upper radius surface 64 of the.

The upper die 120 stops the closing of the press 100 when the upper die 120 and the lower die 108 are fully closed and thus prevents excessive compression of the upper radial surface 64 of the retainer ring 48. Further comprises a bonding surface 136 that bonds with a corresponding bonding surface on the lower die 108.

The first compression surface 136 and the second compression surface 132 are spaced vertically within the upper die 120 by a specific distance selected such that deformation of the upper radius surface 64 can result in a good gap 60. do. As will be appreciated by those skilled in the art, this vertical spacing may be based on the design of the upper die 120, the relative distance between the first compression surface 136 and the second compression surface 132, of the material from which the retainer ring 48 is formed. Thickness and the vertical height of the components of the disc recliner device 20 loaded into the press 100 for staking.

Once the correct vertical separation has been determined and the upper die 120 is fabricated, a disc such as a change in feedstock material in which the retainer ring 48, serrated plate 28 or guide plate 24 is stamped or otherwise formed Changes in the thickness of the components of the recliner device 20 result in too small a gap causing breakage of the disc recliner device 20 or in too large a gap causing BSR noise.

Thus, in the method of the present invention, a set of top dies 120 is fabricated, each die being different to accommodate the change in feedstock material of the apparatus 20. In the presently preferred embodiment, a set of three upper dies 120a, 120b and 120c are fabricated as shown in FIGS. 7A-7C.

The upper die 120a is fabricated with the spacing 140 between the first compression surface 136 and the second compression surface 132 being a nominally accurate separation determined as described above.

Upper die 120b is fabricated with one selected size where the spacing 144 between first compressive surface 136 and second compressive surface 132 is less than spacing 140.

Upper die 120c is fabricated with one selected size where the spacing 148 between first compressive surface 136 and second compressive surface 132 is greater than spacing 140.

According to the method of the invention, an upper die of one of a set of upper dies, such as upper die 120a, is mounted in the press 100, and then the parts for assembling the disc recliner device 20 or other device are pressed. Dropped into 100, press 100 is circulated to produce test apparatus 20. Although only a single test device 20 needs to be produced, it is presently desirable to produce three or more test devices 20 to ensure that the press 100 operates under its normal operating conditions.

Each test apparatus 20 is in turn removed from the press 100 and inspected by a press operator or other object or system to determine if a good value for the gap 60 has been properly achieved.

If a good value for the gap 60 has been achieved for the test device 20, until a group of changes occur for any part of the device 20 that affects the gap 60 of the device 20. Production of the device 20 may proceed.

In particular, each associated part of the apparatus 20 consists of a batch, each group formed from a single lot of feedstock material for that part. Thus, for example, if the guide plate 24 of the device 20 is formed by stamping from a steel feedstock, when the lot of feedstock is consumed, the stamped guide plate 24 constitutes a group, Guide plates 24 stamped from the steel feedstock of the lot will constitute a new group.

In the method of the invention, one or more test devices 20 are fabricated and inspected each time any group of related parts of the device 20 changes. As will be apparent to those skilled in the art, the relevant parts of the device 20 are those in which the change in the dimensional tolerance affects the resulting dimension of the gap 60.

If it is determined that the gap 60 of the test device 20 is too large when the test device 20 is inspected, the upper die 120 (120a in this example) is removed from the press 100 and the removed upper die ( With respect to 120, the upper die (120b in this example) is replaced with a reduced spacing between the first compression surface 136 and the second compression surface 132.

Then, one or more additional test devices 20 are formed in the press 100 together with the replacement top die 120, and these additional test devices 120 are then inspected to determine if the gap 60 is in a good range. do. If gap 60 is acceptable, production of device 20 may proceed until the next occurrence of a group of changes occurs for any relevant component of device 20.

If the gap 60 is beyond the good range, the upper die 120 is removed from the press 100 and reduced between the first compression surface 136 and the second compression surface 132 for the removed upper die. It is replaced with another upper die with spaced gaps, and one or more test devices 20 are rebuilt and tested.

Alternatively, if the test apparatus 20 is inspected and it is determined that the gap 60 is below the good range, the upper die 120 in the press 100 is removed and the upper die 120 removed for the removed upper die 120. The increased distance between the first compression surface 136 and the second compression surface 132 is replaced by the upper die 120 (such as the upper die 120c). Then, one or more test devices 20 are fabricated and tested with the replacement top die. If the test apparatus has a gap 60 in a good range, the production of the apparatus 20 proceeds under the following group of changes. Conversely, if the test apparatus is not staking within the design specification, the upper die 120 has increased spacing in the case of a gap 60 smaller than the good range or in the case of a gap 60 larger than the good range. Exchanged with a suitable alternative upper die 120 with reduced spacing.

As will be apparent to those skilled in the art, the present invention is not limited to the use of any particular number of strained upper dies, and an appropriate number of strained dies will depend on the expected strain in the feedstock material. In the present use of the method of the present invention, it has been found that three deformable top dies 120 are sufficient, but in other situations a larger or smaller number of variants may be appropriate.

In the second embodiment of the present invention, the compression and / or deformation of the surface 64 for setting the gap 60 and the staking of the components of the device 20 were separated into separate fabrication steps. In this embodiment, the device 20 is staked in a conventional staking press. The staked device 20 then includes a ram having a shape complementary to the bottom surface of the device 20 and a lower die rested to support the bottom surface of the device 20 and a compression die mounted thereon. It is dripped into a clearance setting press. The compression die is shaped to engage and properly deform the surface 64 when the ram is moved toward the lower rest.

To set the gap 60, the ram of the gap setting press is moved towards the device on the lower rest so that the compression die is in contact with the surface 64. A control system such as a microcontroller monitors the force exerted on the surface 64 by the ram through the compression die and controls the ram such that a preselected force is exerted on the surface 64, after which the ram is retracted.

The preselected force can be determined in a variety of ways, including empirical tests, and is a force sufficient to deform the surface 64 to obtain the gap 60 within a good range of the gap.

In one preferred embodiment, the preselected force is selected such that the surface 64 (or shape on the surface 64, such as a dimple, etc.) comes into contact with the serrated plate 28 and the gap 60 is rammed. And by recoil of the surface 60 when the compression die is retracted.

As will be apparent to those skilled in the art, the preselected forces and recoil of the surface 64 are substantially independent of the expected change in tolerances in the components of the device 20, and therefore the fabrication of the device 20 in this embodiment of the present invention is a group of It does not have to be arranged in the production process can be carried out in a continuous process.

The present invention provides a new method of staking a part in a mechanical device to achieve a staked device having a gap between one or more good parts, regardless of feedstock changes in the material used to form the part. The variants are fabricated for at least one staking die of a pair of staking dies used in the staking press, and a variant having an appropriate staking gap is selected each time a group of parts changes. In this way, the deformations between the lots of feedstock material used to form the part will not result in other staking results that do not meet the design specifications for the staked device or devices experiencing lateral looseness. . In a second embodiment, the device is first staked into a conventional staking press and then dropped into a gap setting press that deforms at least a portion of the staked device to obtain a good gap. By carefully limiting the force at which deformation is performed, a good gap can be obtained without requiring a group of parts in the fabrication process.

The above-described embodiments of the invention are intended as examples of the invention, and alternatives and modifications may be practiced by those skilled in the art without departing from the scope of the invention, which is defined only by the claims appended hereto.

Preferred embodiments of the invention will now be described by way of example only with reference to the accompanying drawings.

1 is an exploded view of a disc recliner for an automobile seat back which may be manufactured according to the present invention.

FIG. 2 is a partial cross sectional view of the staked disc recliner of FIG. 1; FIG.

3 is a cross-sectional view of a portion of a staking press according to the method of the present invention with the press open and loaded with a set of parts for the disc recliner of FIG.

FIG. 4 is a cross sectional view similar to the view of FIG. 3 with the press closed to stake the upper and lower parts of the device together;

5 is a side cross-sectional view of the upper die useful for the press of FIG.

Figure 6 is a perspective view of the die of Figure 5;

7A-7C are some side cross-sectional views of three upper dies that may be employed with the press of FIG.

<Explanation of symbols for main parts of the drawings>

20: disc recliner 24: guide plate

28: serrated plate 32: pole

36: spring 40: shaft

44: cam 48: retainer ring

60: gap 100: press

116: ram 108: lower die

120: upper die

Claims (3)

A method for staking an assembly of parts in a mechanical device, (Iii) forming at least one test device using a pair of staking dies in a press, (Ii) inspecting at least one test device to determine whether gaps between components in the device have been properly achieved; (A) changing the at least one staking die of the pair of staking dies in the press and restarting the method in step (iii) if the gap has not been adequately achieved; (I) creating the devices with a pair of staking dies, if the gap has been properly achieved; If a group of changes occur in any part staked in the device and the dimensional change in the changed part can affect the gap, the part in the mechanical device comprising the step (i) of restarting the method in step (iii). Assembly staking method. The method of claim 1, wherein step (iii) determines whether the gap of the one or more test apparatus is too large or too small, and if too small, increases the gap of the die to at least one die of the pair of dies. Changing at least one die of the pair of die to change or reduce the gap of the die if too large. The resulting devices are a method for staking an assembly of parts in a mechanical device having a preselected gap between two or more parts, Dropping the parts into a staking press and staking the parts to form a staked device, Stay in a clearance setting press comprising a support on which the staked device is placed and a compression die attached to the ram and operable to engage a portion of the staked device to deform a portion of the staked device to set a preselected clearance. (Ii) loading the loaded device; Moving the ram such that the compression die is brought into contact with the portion of the staked device with a preselected force to deform a portion of the staked device to set a preselected clearance (iii). Way.

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