Mar a tha inneal torsion Spring ag obair gu fìrinneach?

You're designing a product with a hinged lid that needs to snap shut or open with assistance. Tha fios agad gu bheil earrach torsion an sàs, ach ciamar a bhios na pàirtean uile ag obair còmhla gus an smachd sin a chruthachadh, feachd cuairteachaidh?

A torsion spring mechanism translates the spring's stored energy into useful work by using a central shaft, puing acair, and the spring's legs. Mar a ghluaiseas an inneal, tha e a' seargadh aon chas de'n earrach, cruthachadh torque a tha a’ feuchainn ris a’ phàirt a thilleadh chun t-suidheachadh tùsail aige.

Bho thaobh saothrachaidh, chì sinn nach 'eil an t-earrach fèin ach leth na sgeòil. Tha fuaran torsion air a dhèanamh gu foirfe gun fheum às aonais uidheamachd air a dheagh dhealbhadh gus taic a thoirt dha. I've seen many designs fail not because the spring was wrong, but because the parts around it didn't allow it to function correctly. Bidh an fhìor dhraoidheachd a’ tachairt nuair a thig an t-earrach, shail, agus bidh puingean acair uile ag obair còmhla mar aon, siostam earbsach.

Dè na prìomh phàirtean de uidheamachd earrach Torsion?

Feumaidh an dealbhadh agad gnìomh cuairteachaidh, but a simple pivot isn't enough. Tha fios agad gu bheil fuaran a’ toirt an fhorsa, but you're unsure how to properly mount and engage it within your assembly.

Tha ceithir prìomh phàirtean ann an uidheamachd earrach torsion àbhaisteach: an t-earrach torsion fèin, bonn sa mheadhan (or coille) gu'n tig e thairis, acair pàipearachd airson aon chas, agus pàirt gluasadach a tha a 'dol an sàs anns an dàrna cas.

Is e mearachd cumanta a chì mi ann an dealbhaidhean ùra a bhith a’ dìochuimhneachadh a’ chrann sa mheadhan. Aon uair chuir neach-dèiligidh prototype thugainn far an robh an t-earrach dìreach a 'seòladh ann an cuas. Nuair a dh'fhosgail am mullach, dh' fheuch an t-earrach ri teannadh, ach an àite torque a chruthachadh, bha a chorp gu lèir dìreach air a chromadh agus air a lùbadh chun an taobh. Feumar taic a thoirt do fhuaran torsion air an taobh a-staigh. A' chas, or coille, a 'cur casg air seo bho bhith a' tachairt agus a 'dèanamh cinnteach gu bheil an lùth gu lèir a' dol a-steach gu cruthachadh glan, feachd cuairteachaidh.

Anatomy of Rotational Force

Tha obair shònraichte aig gach pàirt den uidheamachd. Ma tha gin dhiubh air a dhealbhadh gu ceàrr, cha bhith an siostam gu lèir a’ coileanadh mar a bhiodh dùil.

• An t-Earrach Torsion: Is e seo inneal an inneal. Trast-thomhas an uèir aige, trast-thomhas coil, agus bidh an àireamh de choilich a’ dearbhadh dè an ìre de torque as urrainn dha a thoirt gu buil.
• An Arbhar (no Mandrel): Seo an t-slat no am prìne a tha a’ ruith tro mheadhan an earraich. Is e a phrìomh obair an t-earrach a chumail co-thaobhadh agus casg a chuir air bho bhith a’ bucall fo luchd. The arbor's diameter must be small enough to allow the spring's inside diameter to shrink as it is wound.
• An t-Acaire Pàipearach: Feumaidh aon chas den earrach a bhith ceangailte gu daingeann ri pàirt neo-ghluasadach den cho-chruinneachadh. Tha seo a 'toirt seachad a' phuing freagairt air a bheil an torque air a chruthachadh. Dh’ fhaodadh seo a bhith na slot, toll, no prìne.
• Am puing conaltraidh gnìomhach: Bidh cas eile an earraich a 'putadh an aghaidh a' phàirt a dh'fheumas gluasad, leithid mullach, luamhan, no dorus. Mar a tha am pìos seo a ' tionndadh, tha e "luchdachadh" an t-earrach le bhith a 'toirt a-mach a' chas gnìomhach seo.

Mar a tha Torque air a thomhas agus air a chuir an sàs ann an inneal?

Feumaidh an uidheamachd agad tomhas sònraichte de fheachd dùnaidh, but you're not sure how to translate that into a spring specification. Choosing a spring that's too weak or too strong will make your product fail.

Torque is calculated based on how far the spring's leg is rotated (sèididh ceàrnach) as a shuidheachadh saor. Bidh innleadairean a’ sònrachadh “ìre earraich" ann an aonadan mar Newton-millimeters gach ceum, a tha a’ mìneachadh dè an ìre de torque a thèid a chruthachadh airson gach ìre de chuairteachadh.

Nuair a bhios sinn ag obair le innleadairean, is e seo an còmhradh as cudromaiche. Dh’ fhaodadh iad a ràdh, “Feumaidh mi am mullach seo a chumail fosgailte 2 N-m of force when it's at 90 ceuman." Is e an obair againn fuaran a dhealbhadh a choileanas an fhìor torque sin aig a’ cheàrn shònraichte sin. Bidh sinn ag atharrachadh meud an uèir, trast-thomhas coil, agus an àireamh de choilich gus an targaid sin a bhualadh. We also have to consider the maximum angle the spring will travel to ensure the wire isn't overstressed, a dh’ fhaodadh a bhith air a mhilleadh no air a mhilleadh gu maireannach.

Dealbhadh airson feachd sònraichte

Is e amas an uidheamachd an ìre cheart de fhorsa a chuir an sàs aig an àm cheart. This is controlled by the spring's design and its position within the assembly.

• A 'sònrachadh ìre an earraich: Is e ìre an earraich cridhe an àireamhachaidh. A "stiùr" tha ìre àrd aig an earrach (generates more torque per degree), while a "soft" spring has a low rate. This is determined by the physical properties of the spring.
• Initial Tension and Preload: In some mechanisms, the spring is installed so that its legs are already slightly deflected even in the resting state. This is called preload or initial tension. It ensures that the spring is already exerting some force from the very beginning of its movement, which can eliminate looseness or rattles in the mechanism.
• Maximum Deflection and Stress: You must know the maximum angle the spring will be rotated to. Pushing a spring beyond its elastic limit will cause it to yield, meaning it won't return to its original shape and will lose most of its force. We always design with a safety margin to prevent this.

What Are the Most Common Failure Points in a Torsion Mechanism?

Your prototype works, but you're worried about its long-term reliability. You want to know what parts are most likely to break so you can strengthen them before going into production.

The most common failure points are spring fatigue, incorrect mounting, and wear at the point of contact between the spring leg and the moving part. An undersized arbor that allows the spring to buckle is another frequent problem.

I've inspected hundreds of failed mechanisms over the years. The most common story is fatigue failure. The spring simply breaks after being used thousands of times. This almost always happens because the wrong material was chosen or the stress on the wire was too high for the application. A spring for a car door that's used every day needs a much more robust design than one for a battery compartment that's opened once a year. A good design matches the spring's expected beatha rothaireachd[^1] to the product's intended use.

Building for Durability

A reliable mechanism anticipates and prevents common failures through smart design and material choices[^2].

• Spring Fatigue: This is a fracture caused by repeated loading and unloading. It typically occurs at the point of highest stress, which is often where the leg bends away from the spring's body. This can be prevented by using a stronger material (coltach ri sreang ciùil), choosing a larger wire diameter to reduce stress, or applying processes like shot peening.
• Anchor Point Failure: If the slot or pin that holds the stationary leg is not strong enough, it can deform or break under the spring's constant force. The material of the housing must be robust enough to handle the pressure.
• Wear and Galling: The active leg of the spring is constantly rubbing against the moving component. Thairis air ùine, this can cause a groove to wear into the housing or the leg itself. Using a hardened steel insert or a roller at the contact point can eliminate this problem in high-use mechanisms.

Co-dhùnadh

A successful torsion spring mechanism is a complete system where the spring, shail, and anchors are designed to work together to deliver precise, repeatable rotational force for the life of the product.

[^1]: Understanding cycle life helps you design springs that meet the demands of their intended use.
[^2]: Tha taghadh nan stuthan ceart deatamach airson coileanadh agus seasmhachd an uidheamachd agad.