如今，OEM開始更多的將注意力關注車輛的動力傳動系統上，并開始與一級供應商合作，以追求更高的效率、更低的重量、更優化的NVH特性以及更低的成本。目前 AAM（AmericanAxle & Manufacturing，中文譯名：美國輪軸制造公司 或 美國車橋制造有限公司）正在展示一種全新Quantum技術，這種技術背后的設計理念正是打造更高效、更輕質、更“智能”的驅動橋系統。Quantum是AAM的系列驅動橋產品，據稱可以為車輛實現30%到40%的質量減少，和20%的功率密度提升。近日，AAM副總裁兼CTO Phil Guys接受了《汽車工程》的采訪，向大家介紹了有關Quantum技術的相關研發情況，摘選如下：
SAE：Quantum的概念從何而來？
Phil：Quantum技術是我們先進工程團隊一次頭腦風暴的成果。那時，我們剛剛完成了一項旨在實現更高能效的內部項目 – 工程團隊采用了新的軸承、更輕的潤滑系統以及超精加工的準雙曲面齒輪。這是一次很常見的迭代，但我們認為其他一級供應商也能和我們做的一樣好，從產品功能的角度來說，這次迭代不能讓我們與其他廠商真正拉開差距。
我們知道客戶想要重量更輕、效率更高、運行安靜、可靠耐用且成本更低的解決方案，在這種背景下，我們再一次進行了嚴肅對話，討論如何才能真正從驅動橋市場中脫穎而出。我們的先進工程團隊開始將目光轉移至汽車行業之外，包括航空航天、醫療器械等領域中任何涉及扭矩能量轉移的設計。
6個月后，也就是2014年，他們拿出了一套方案，這也就是現在的Quantum技術。Quantum技術的橋設計采用了一套截然不同的齒輪支持結構，結合了適用于后驅動車型的梁式橋和獨立后懸掛（IRS）設計以及一款全輪驅動（AWD）系統。當時我們認為這種概念過于激進，可能不會有客戶感興趣。
SAE：Quantum技術“激進”在哪兒？
Phil：嗯，這種解決方案與傳統的橋設計有很大不同，我們的一些客戶可能會有點懷疑，別人都沒見過這種設計，因此我們肯定要盡可能地提供更多的驗證、開發、效率、NVH和耐用性數據，打消大家的疑慮。此外，我們還打造了多款演示原型，以展示Quantum產品的安靜運行能力。
我們打造了一款梁式橋，這是目前公司產品目錄中最大的一款產品，也是Quantum技術的首個真正應用。我們認為，減重和提效應該是卡車市場優先考慮的重點，而我們的演示原型實現了30-35%的減重效果。目前，一款1500系列皮卡的標準梁式橋重量為82公斤（180磅），而Quantum解決方案的重量僅為57公斤（125磅），減重比例高達30%；2500系列皮卡的標準梁式橋重量為144公斤（317磅），Quantum解決方案的重量為98公斤（180磅），減重比例達30-40%。目前，我們還沒有嘗試量化Quantum可以在車輛減重方面發揮的作用，這可以留給客戶自己去做。
無論何時，Quantum技術總能給不同應用帶來減重方面的能力提升。與現有技術先比，采用Quantum技術的AWD車型可實現40%左右的減重。“我們已經減低了40%的寄生損失，并取得了大約1%的燃料經濟性提升。”之前，我們已經完成了一次迭代，并對Quantum進行了更多優化。14個月前，我們又完成了對Quantum技術的第二次迭代，并開始向客戶正式介紹這款產品。
SAE：Quantum技術的“秘密武器”是什么？
Phil：現在，我們還不會透露Quantum技術的內部結構，但可以說這款產品的核心在于采用了356號熱處理鋁材。我可以告訴你，雖然我們采用的金屬環-小齒輪滾珠軸承來自航空航天領域，但成本卻相當親民！我們通過這種滾錐軸承實現了產品的差異化。Quantum系列產品的所有能效提升均來源于金屬環-小齒輪軸承結構的支持，這些軸承并非雙排設計，也無需事先加載，因此我們并沒有使用墊片，而為了預先加載小齒輪軸承，通常墊片在車橋設計中的使用非常常見。這就是Quantum設計中最激進的地方。
SAE：外殼和軸承座的設計也有不同嗎？
Phil：是的，這兩處的設計是完全不同的，但創新之處在于，我們將如何以最緊湊、最高效的方式將這些軸承應用在我們車橋設計中。
OEMs are increasing their focus on the vehicle driveline, working with Tier 1s to wring out greater efficiencies, mass and NVH reduction and cost. Making drive axles as efficient, light and ‘intelligent’ as possible was the impetus behind the new Quantum technology now being demonstrated by American Axle & Manufacturing. Quantum is a family of drive axles that AAM claims deliver a 30 to 40% mass reduction and 20% greater power density as incumbent axles with the same torque capacity. Phil Guys, AAM’s Vice President and CTO, recently spoke with AE about Quantum developments.
Where did the Quantum concept come from?
From a brainstorming session with AAM’s advanced engineering team. We’d just been through an internal project aimed at seeking greater efficiencies—new bearings, lighter weight lubes, superfinished hypoid gears. A very iterative exercise, but we concluded that all of us in the Tier-1 axle space can do that. From a product-functional perspective there’s not a lot of differentiation.
We had a significant dialogue about how do we truly differentiate ourselves in the market, knowing that customers want less weight, more efficiency, quiet operation, reliability and durability, at reduced cost. So our advanced team benchmarked products outside the automotive space, including aerospace, medical—anything with a torque element to it that had to transfer energy.
Six months later—this was in 2014—they came up with a proposal. And the idea that came out of it, now called Quantum, was so radical that we thought no one would want to buy it. Quantum technology is all about a totally different approach to the axle’s gear-support structure. The concept encompasses beam-axle and IRS [independent rear suspension] versions for rear-drive applications, and an AWD derivative.
What makes it ‘radical’?
Well, it doesn’t look like a traditional axle so there was a bit of skepticism from some of our customers. It is a different-looking animal so we were right to gather a tremendous amount of validation, development, efficiency, NVH and durability data in support of the technology. We also built models to prove that it’s a quiet axle when installed in a vehicle.
We built a beam axle, the biggest product in AAM’s portfolio. It’s the first application of this technology; we felt the truck market would be looking for weight and efficiency improvements as a priority. And in our prototype we saw a 30-35% weight reduction. A benchmark beam axle for a 1500-series pickup weighs 82 kg [180 lb]; the Quantum is 57 kg [125 lb]; that’s a 30% mass reduction. A benchmark 2500-series axle is 144 kg [317 lb]; Quantum is 98 kg [180 lb], so we took 30-40 pounds out of that. We haven’t even tried to quantify the savings on the vehicle side that can come from the “cascade” benefits we bring; we’ll let the customers do that.
Each time we applied the technology in a different application we saw weight-reduction improvements. On the AWD version the weight savings is about 40% relative to current-market technology. And we’re seeing on the order of 40% reduction in parasitic losses. We quantify that as about a 1% improvement in label-type fuel economy to the vehicle. We went through one iteration and found more opportunities to make it even better. We did a second iteration, tweaked it a bit more and started taking that technology to our customers about 14 months ago.
What’s AAM’s ‘secret sauce’ for Quantum?
I’m not ready to show the insides just yet. The center section is heat-treated 356. I can tell you that while the new ball bearings we’re using for ring-and-pinion support are from aerospace applications, their cost isn’t! We use tapered roller bearings for the differential. All of our efficiencies are coming out of the ring-and-pinion support. Those bearings are not double-row and are not preloaded, so we don’t use shims [typically used in axles to set pinion bearing preload]. The design is radical in this regard.
Is the IP in the case design and bearing saddles?
Yes, they’re totally different. But the innovation is in how we apply these bearings in an axle in the most compact, efficient manner.
Author: Lindsay Brooke
Source: SAE Automotive Engineering Magazine
AAM的首席技術官 Phil Guys表示，“我們已經減低了40%的寄生損失，并取得了大約1%的燃料經濟性提升。”