0366-發(fā)動機(jī)加速度過載模擬實驗臺設(shè)計【全套6張CAD圖】
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外文翻譯
原文:
Proceedings of the 7th ICFDM2006
International Conference on Frontiers of Design and Manufacturing
June 19-22, 2006, Guangzhou, China
THE SWAGING TECHNOLOGY USED IN SHAFT CLINCHING
ASSEMBLY FOR AUTOMOTIVE HUB BEARING UNIT
Xiao Yunya 1, 2 , Zhou Zhixiong1and Lv Jianmin3
1College of Mechanical and Automotive Engineering, Hunan University, China
2Department of Electromechanical Engineering, Shaoguan University, China
3Shaoguan Southeast Bearing Co., Ltd.,China
Abstract: Recently, shaft end clinching is being adopted in the hub bearing unit assembly, which will raise as technological trend and gradually replace clamp nut in future. In a machine reconstructed from lathe, the sample of shaft end clinched hub unit is successfully manufactured by swaging technology with given parameters. Some tests confirm that the shaft end clinching hub unit has functions greater than the traditional hub unit with clamp nut. In the end, the future application and the further research direction of the swaging technology are discussed.
Key Words: hub bearing unit, swaging, shaft clinching, assembly
Hub unit bearings are widely being adopted for cars as they are lighter and stronger and easily to mounting. In the hub bearing unit assembly, the shaft clinching tightening replaces clamp nut and becomes technological trend. It is adopted in the mostly famous international companies of bearing manufacture. However, the deformation of the workpiece in clinching process is complex and difficult to be controlled. It brings phenomenons such as distortion of structure in the connecting area, shortage of supporting rigidity, inadequacy of strength, disqualification of rotational accuracy and lack of life. Thus leads the hub unit to invalidation easily. Up to now, the swaging technology used in shaft clinching for hub unit is not well mastered. With the support from some corporations, the pilot study of the swaging technology is completed. The problems from technics and equipment of clinching are solved, and the sample of swaged edge of hub bearing unit is manufactured successfully.
1. Introduction
Hub bearing unit is assembled from several components, which is pre-adjusted and lubricated for life.
The unit was originally designed for use in cars and trucks to replace the traditional taper roller bearings, which is ready to install and free maintenance. With the hub bearing units not only the number of parts, but also the overall weight of the wheel arrangement is reduced. They also reduce assembly time because they do not require any special adjustment. Each unit is self-contained and
ready to be bolted in place. This kind of bearing has come through three generations since it was designed by SKF in 1938. The 4th generation hub unit is now under development though it has not yet been mass-produced. Figure 1 illustrates the structure of hub bearing units [3].
The 1st generation hub bearing unit is composed of two single-row bearings with their outer rings integrated, where grease is filled with seals. Compared with the 1st generation, the 2nd generation hub bearing unit is much more light weight and miniaturization , which has integrated flange into the outer ring of 1st generation wheel bearing. The 3rd generation hub bearing unit is an advanced type of 2nd generation, which the outboard inner ring of the inner-ring rotation type hub unit and hub-shaft are integrated. In this generation hub unit, number of built-in high-performance sensor type has increased. [2]
Figure.1 Hub unit bearings
To further reduce the weight and size of the hub bearing unit and improve its reliability, NSK has recently developed a novel shaft end clinching hub unit. In the new hub design, the clamp nut which fastens the inner and outer rings together is replaced with a swaged edge. The swaging that used in shaft clinching is a technique that deforms the end part of hub shaft by swaging forging in which inboard of inner ring and proper shaft force by this deformation. Figure 2 shows examples of 3rd generation type clinched shaft hub units for a driven wheel and drive wheel respectively. In addition, this technique is also applicable to the inner ring rotation type 2nd generation hub units [2].
driven wheel drive wheel
Figure2 Shaft clinching hub unit
There are several advantages of the swaged hub unit in comparison to conventional retaining nut assemblies. The nut is saved in the swaged hub unit. The swaged hub unit’s size is smaller and weight is less than the conventional retaining nut assemblies. The structure of the unit becomes compact. And the vehicle fuel consumption is reduced [1]. The clamping force can be controlled accurately during the swaging process. Then the effect of error from parts is avoided. The fluctuation of pre-adjusted force is reduced greatly. As every hub unit gains the best pre-adjusted force after assembly, the life of bearing unit can be extended. The clinching tightening is an un-reversible assembly. The assembly is not failure though the vibration caused from running process is been loaded on the hub unit. The shaft clinching process is capable to perfectly comply with the problem of “l(fā)oosening of tightening” that was impossible to be solved for the nut tightening. Then the shaft clinching improves the reliability and safety of the product greatly. This technology enables resource and energy of the manufacture of hub bearing unit to be saved. Due to predigest the assembly process, the cost of the whole vehicle is further reduced.
2. Process and Experiment
The swaging process is an applied “rocking die forging”. Figure 3 illustrates the principle of the rocking die forging [3]. On the center point of a workpiece, the axis OY of a conical upper die, which is titled by an angle αfrom the centerline OX of the work, is turned about the OX axis. This gives rocking motion to the upper die, and the workpiece is continuously formed as the upper die continues the rocking rotation.
The motions needed by the shaping principle can be achieved from a lathe. As Figure 4 showing, a rolling head is fixed on the end of the lathe shaft. The head is tilted an angle αfrom the centerline of workpiece and self-rotating. The workpiece is fixed on the worktable restructured from the tow- board which is drived by hydraulic pressure. During the rolling process while the tilted rolling head is rotated on the bearing assembly, the shaft end of the flanged inner ring (workpiece) will receive a pressure provided from hydraulic-driving worktable and yield plastic deformation until it is firmly fixed to the smaller inner ring. Photo 1 shows the reconstructed machine.
Figure3 Principle of the rocking die forging
Figure4 The motions needed by the shaping principle
The rolling head is the key unit device for the swaging experimentation. Figure 5 illustrates its structure. It is consisted of a roll-wheel, a bearing, a nut, 3 inner hexangular bolts and a joining- tray. The bearing is a double row angular contact ball bearing, actually a hub bearing unit, which supports both of the double-direction axial forces and the radial force. It ensures the roll-wheel to be self-revolving with the effect of friction from the contact area between the roll-wheel and the workpiece during the swaging process. The rolling head is fixed on the lathe shaft with the joining-tray which can adjust its gradient angle to meet the angle needed between the rolling head and the centerline of workpiece. The roll-wheel swages the workpiece, endures heavy force and serious attrition. Special material with the capabilities to endure the force and attrition is adopted to manufacture the roll-wheel, and especial heat treatment is adopted to ensure the perfect strength and rigidity.
Photo 1 The reconstructed machine for swaging
In order to ensure the quality of the clinching assembly, the shape of the rolling head used in the experimentation should be optimized. It is not enough to only have purely axial grinding- pressure but also to keep the perfect radial grinding pressures in the process of the clinching assembly. The key is that the diameter of the ball-head of the rolling head should be larger than that of the inner hole of the bearing, and keep an appropriation touching angle. At the same time, the rolling head must be grinding with no slippage in the process of the swaging so as to avoid the hub unit rotation caused by the friction when touching each other, thus reducing the quality and the precision of the clinching assembly
The swaging process is executed in the reconstructed lathe machine. Although the processing load is small as a result of the rolling head inclination angle α, axial and radial loads are applied to the assembly during the swaging process. This can result in potential adverse effects that influence bearing performance, such as deformation or stiffness of the rolling elements and raceways. To eliminate or reduce these adverse effects, it thus becomes necessary to confirm the technical parameter through the swaging experimentation. After repetitious experiments on swaging, the parameter is confirmed at last. Under the integrated effect of the given parameters which includes pressure, loading speed and rotating speed, the sample of swaged end hub unit is successfully manufactured. Photo 2 shows the real product.
Figure5 The rolling head
Photo 2 The sample of swaged end hub unit
3. Conclusion and Discussion
In order to examine the static strength of the swaged edge, a static strength test was carried into execution. A moment load was applied until the bearing failed. At the end, neither the swaged bearing nor the bearing assembled with a clamp nut failed at the fastening joint. Failure occurred in the flanged inner ring at the corner of the mating face with the smaller inner ring. The test determined that the swaged edge was not the weak point of the bearing. Photo 3 shows the failure of hub bearing unit. In addition, the sample of swaged hub bearing unit also passed the running endurance test under heavy load. It verified that the swaged edge is sufficient for fatigue strength. It is indicated on the result of the test that swaged hub bearing unit has functions greater than the traditional hub bearing unit with clamp nut.
Although the feasibility of swaging used in shaft clinching for hub bearing unit assembly is confirmed on the experimentation and the sample of swaged end hub unit is manufactured successfully, but still there are many problems waiting to be solved before mass-produce. In order to master the swaging technology entirely, a general research should be demanded to perform. It includes analyzing the potential failure mode of swaging, simulating the plastic deformation course of the hub unit during the swaging process and optimizing the geometric shape of the shaft edge and roll-wheel. Based on these studies, many base theories of swaging can be constructed and some key technologies for swaging the hub unit can be mastered. Using these theories and key technologies, a novel high efficient and precise special swaging machine for shaft clinching hub units will be developed.
Photo 3 The failure of hub bearing unit
It is quite important to master the swaging technology for manufacture either the 2nd generation and 3rd
generation hub units or the new generation hub unit. As a hub unit, it should includded bearing assemblies. These new generations of hub bearing unit are not exceptions. Figure 6 shows the structure of hub 4, hub 5 and hub 6 designed by SKF. Because the bearing assemblies are composed of outer ring, rolling balls, flanged shaft and inner ring, it is pivotal to adopt the swaging technology when assemble them into a unit, thus it’s significant to develop the swaging technology for the shaft clinching assembly.
Hub4 Hub5 Hub6
Figure6 New generations of hub bearing unit
It is discovered by analyzing the conFigureuration of the hub bearing unit in detail that the number of parts of the hub unit can be further reduced with the swaging technology used in shaft clinching. The shaft end of theflanged inner ring may be directly swaged to raceway, and the smaller inner ring can be saved, then the parts of the unit are decreased. Thus it will predigest the structure of the hub unit, improve the reliability, reduce the cost of manufacture. One reason of this design is that the tightening position is not the weak point of the hub unit, but the root of the flanged inner ring. The other is informed by the FEM analysis that small inner ring receives not heavy axial load during the vehicle running, so the small inner ring can be saved. But before putting this project in practice, the key questions such as assembly of the balls, the dimension precision of the swaged raceway, the plastic deformation under heavy pressure must be solved.
References
[1] Junshi Sakamoto. Trends and New Technologies of Hub Unit Bearings.Motion & Control, 2005(17):2~9
[2] T.NUMATA. Technical Trends of Automotive Wheel Bearings. KOYO Engineering Journal English Edition, 2003(162E):32~36
[3] Hirohide Ishida,Takeyasu Kaneko. Development of Hub Unit Bearing with Swaging. Motion &
Control,2001(10):9~14
[4] K.TODA,T.ISHII,S.KASHIWAGI,T.MITARAI.. Development of Hub Units with Shaft Clinching for Automotive Wheel Bearings. KOYO Engineering Journal English Edition,2001 (158):26~30
Contact Info:
Zhou Zhixiong
Professor
College of Mechanical and Automotive Engineering
Hunan University
Hunan, ChangSha,410082 China
Phone:86-731-8821732 Fax:86-731- 8821732
Email:zhouzx8@163.com
Website: http://jqy.hnu.cn
翻譯:
正在進(jìn)行的2006第七屆關(guān)于前沿的設(shè)計和制造的ICFDM國際會議,
2006年 6月19日至22日, 中國,廣州
模鍛技術(shù)通過軸釘牢裝配應(yīng)用于汽車輪轂軸承單元
肖云亞1,2,周志雄1和呂建民3
1 中國 湖南大學(xué) 機(jī)械與汽車工程
2 中國 韶關(guān)大學(xué) 機(jī)電工程
3 中國 韶關(guān) 東南軸承有限公司
摘要:最近,軸端釘牢正在被輪轂軸承單元裝配中所采用, 這將成為科技發(fā)展趨勢,并在將來逐漸取代螺母夾緊。 在一臺由車床改裝過的機(jī)器上,軸端釘牢輪轂單元樣品按特定參數(shù)通過模鍛技術(shù)成功的被研制。 一些試驗證實,軸端釘牢輪轂單元的功能,比傳統(tǒng)的螺母夾緊的輪轂單元更完善。 最后,關(guān)于模鍛技術(shù)的應(yīng)用前景和進(jìn)一步研究的方向被討論。
關(guān)鍵詞: 輪轂軸承單元,模鍛, 軸釘牢,裝配。
輪轂單元軸承被廣泛采用于轎車,因為他們都更輕和更強(qiáng)且易于安裝。 在輪轂軸承單元裝配中,軸釘牢夾緊取代螺母夾緊,成為技術(shù)趨勢。 它被大部分國際著名的軸承制造公司所采用。 然而,工件的變形在釘牢的過程中很復(fù)雜,很難加以控制。 它導(dǎo)致如結(jié)構(gòu)的連接部位變形,支持剛度不足,受力不均,旋轉(zhuǎn)精度降低和使用壽命減少的現(xiàn)象。 因而易導(dǎo)致輪轂單元失效。 到現(xiàn)在為止,通過輪轂單元應(yīng)用于軸釘牢的模鍛技術(shù),還不能很好的掌握。在一些企業(yè)的支持下模鍛技術(shù)的初步研究已經(jīng)完成。釘牢的工藝和裝備問題已經(jīng)解決, 具有陷型邊緣的軸端釘牢輪轂單元樣品制造成功。
1、 介紹
輪轂軸承單元是由幾個部分組成,即預(yù)調(diào)整和終身潤滑。 準(zhǔn)備安裝和免費(fèi)維修的該單元最初設(shè)計是為了使用在汽車和卡車上,以取代傳統(tǒng)的圓錐滾子軸承。 這種輪轂軸承單元不僅包括若干組成部分,而且整排車輪的重量減少了。它們也減少了裝配時間,因為他們并不需要任何特殊的調(diào)整。每個單位是獨(dú)立的,并準(zhǔn)備用螺栓固定到適當(dāng)?shù)奈恢?。這種軸承歷經(jīng)了三代,自從它在1938年被SKF設(shè)計出來。 第四代輪轂單元目前正在開發(fā)但尚未批量生產(chǎn)。圖1舉例說明輪轂軸承單元的結(jié)構(gòu)[3]
第一代輪轂軸承單元由被一個外圈整合的兩個單排軸承組成的,利用油封里邊充滿了黃油。相比第一代,第二代輪轂軸承單元更為輕巧和小型化, 它把第一代輪轂軸承外圈整合成法蘭。第三代輪轂軸承單元是第二代軸承的一種改進(jìn)類型, 其中內(nèi)圈的外側(cè)是由內(nèi)圈可以旋轉(zhuǎn)的輪轂單位和輪轂軸整合為一體的。在這一代輪轂單元中,內(nèi)置式高性能傳感器類型有所增加。
圖1 輪轂單元軸承
為了進(jìn)一步減少輪轂軸承單元的重量和體積,并提高其可靠性NSK最近開發(fā)出一種新型軸端釘牢輪轂單元。在這種新的輪轂設(shè)計中,扣緊內(nèi)圈和外圈的夾緊螺母一起被陷型邊緣所代替。這種應(yīng)用于軸釘牢的模鍛是一種通過模鍛使輪轂軸末端變形,軸承內(nèi)圈的內(nèi)側(cè)和軸的特定部位通過這種變形而壓緊的技術(shù)。
2、 過程和實驗
模鍛是一種應(yīng)用“搖動鍛造”過程。圖3是搖動鍛造的原理圖。放在中心點(diǎn)上一個加工件,Y軸上是一個與X軸中心線呈α度的圓錐形的上模,這個上模轉(zhuǎn)向X軸。這就給上模一個搖擺運(yùn)動。工件隨著上模的不斷擺動逐漸成型。
被動輪 主動輪
圖2 軸釘牢輪轂單元
模鍛輪轂單元較之傳統(tǒng)的螺母鎖緊裝配有幾個優(yōu)點(diǎn)。模鍛輪轂單元節(jié)省了螺母。模鍛輪轂單元比傳統(tǒng)的螺母鎖緊裝配的尺寸更小,重量更輕。這種單元的結(jié)構(gòu)更加緊湊。汽車燃料消費(fèi)量也減少了[1]。加緊力能被準(zhǔn)確的控制在模鍛過程中。那么部件誤差的影響就能避免。預(yù)緊力的波動大大降低。當(dāng)每個輪轂單元裝配后經(jīng)過最佳的預(yù)緊,軸承單元的使用壽命會增大。釘牢收緊是一種不可逆的裝配。這種裝配不會失敗,雖然受載的軸承單元在轉(zhuǎn)動的過程中會產(chǎn)生振動。軸的釘牢過程是能夠完全根據(jù)實際情況“松或緊”的,而螺母鎖緊是不可能做到的。因此軸釘牢能極大改進(jìn)產(chǎn)品的可靠性和安全性。這個工藝能夠節(jié)約制造輪轂軸承單元的成本和能量。由于簡化了裝配過程,整車成本進(jìn)一步降低。
需要修整原則的運(yùn)動通過一臺車床可以實現(xiàn)。如圖4所示,一個旋轉(zhuǎn)頭被固定在車床的軸上。這個旋轉(zhuǎn)頭傾斜于加工件中心線α度并繞它旋轉(zhuǎn)。加工件被固定在工作臺上隨液壓驅(qū)動的拖曳板被調(diào)整在旋轉(zhuǎn)的過程中,軸承組合件帶動旋轉(zhuǎn)頭旋轉(zhuǎn)。軸端法蘭內(nèi)圈(加工件)將受到一個由液壓工作臺提供的壓力并產(chǎn)生塑性變形直到它穩(wěn)定的固定在更小的內(nèi)圈上。照片1顯示是的一臺被改造的機(jī)器。
圖3模鍛件的擺動原理
圖4修整原則需要的運(yùn)動
這個旋轉(zhuǎn)頭在模端實驗中是一個關(guān)鍵單元裝置。圖5是它的結(jié)構(gòu)圖。它由一個滾動輪,一個軸承,一個螺母,三個內(nèi)六角螺栓和一個連接盤構(gòu)成。軸承是雙列角接觸球軸承。實際上一個輪轂軸承單元,同時承受軸向力和徑向力。它確保在轉(zhuǎn)動過程中受到滾輪和加工件接觸部分的摩擦力的影響滾輪能圍著自身旋轉(zhuǎn)。這個旋轉(zhuǎn)頭利用連接盤被固定在軸端,這個連接盤能夠調(diào)節(jié)自身的傾斜度來滿足旋轉(zhuǎn)頭和工件中心線的角度要求。滾動輪型鍛加工件,要承受很大的力和嚴(yán)重的磨損。用能承受力和磨損的特殊材料制造成滾輪并且采用特殊的熱處理來保證滿足要求的硬度和強(qiáng)度。
照片1 為模鍛改造的機(jī)床
為了保證訂牢裝備的質(zhì)量,旋轉(zhuǎn)頭的形狀在實驗中要被最優(yōu)化的。在釘牢的過程中它不僅要有足夠的完全的軸向摩擦力,還要保持滿足要求的徑向磨削力。關(guān)鍵是球頭的直徑即旋轉(zhuǎn)頭要比軸承內(nèi)孔要大并保持一個足夠的接觸角度。同時,在模鍛過程中旋轉(zhuǎn)頭必須沒有滑動以防止因為接觸到其他地方造成的摩擦帶動輪轂單元旋轉(zhuǎn)。因此減小訂牢設(shè)備的質(zhì)量和精度。
圖5旋轉(zhuǎn)頭
照片2模鍛輪轂?zāi)┒藛卧獦悠?
3.結(jié)論和討論
為了檢查模鍛邊緣的靜應(yīng)力。一個靜態(tài)應(yīng)力測試被實施。應(yīng)用一個瞬時載荷直到軸承失效。最后,通過螺母夾緊的模鍛軸承和軸承組合體都沒有失效,只有夾緊連接處實效。失效發(fā)生在法蘭內(nèi)圈和更小內(nèi)圈的緊密配合面。測試證明模鍛邊緣并不是軸承的危險點(diǎn)。照片3顯示的是輪轂軸承單元的失效。另外,輪轂軸承單元的樣品也通過了在重載荷下的轉(zhuǎn)動應(yīng)力測試。它校驗了模鍛邊緣具有足夠的疲勞應(yīng)力。測試的結(jié)果需要被指出的是,模鍛輪轂軸承單元比螺母夾緊的傳統(tǒng)輪轂軸承單元功能更強(qiáng)大。
雖然輪轂軸承單元裝配應(yīng)用軸釘牢的可行性只在實驗中被確認(rèn)和模鍛輪轂?zāi)┒藛卧獦悠繁怀晒χ圃?。不過批量生產(chǎn)之前仍然有很多問題等待被解決。為了完全掌握模鍛技術(shù),一個綜合性的研究要求被執(zhí)行。它包括分析模鍛樣式的潛在失效,模擬輪轂單元在模鍛過程中的塑性變形和使軸端和滾論的幾何形狀的最優(yōu)化?;谶@些研究,許多基礎(chǔ)理論能夠被創(chuàng)立并且一些關(guān)于模鍛輪轂單元的關(guān)鍵工藝能夠被掌握,利用這些理論和關(guān)鍵工藝,一個用來制造軸釘牢輪轂單元的新穎的高級的有效的專用模鍛機(jī)床將被發(fā)展。
照片3輪轂軸承單元的失效
為了精通制造的模鍛工藝這是非常重要不管是第二代和第三代輪轂單元還是新一代輪轂單元。一個輪轂單元應(yīng)該包括軸承組合件。這一點(diǎn)對于新一代輪轂軸承單元也不例外。圖6顯示的是由SKF設(shè)計的輪轂4,輪轂5,和輪轂6的機(jī)構(gòu)。因為軸承組合件包括外圈,滾動體,凸緣軸和內(nèi)圈,采用模鍛技術(shù)集合它們到單元里面去是關(guān)鍵的,因此為軸釘牢裝備發(fā)展模鍛技術(shù)是有意義的。
輪轂4 輪轂5 輪轂6
圖6 新一代輪轂軸承單元
通過詳細(xì)分析輪轂軸承單元的外型,通過應(yīng)用于軸釘牢的模鍛技術(shù)軸承的組成部件數(shù)量能更進(jìn)一步減少被發(fā)現(xiàn)。帶凸緣的內(nèi)圈的末端也許能被模鍛到軸承溝上。更小的內(nèi)圈也許能夠省略。到那時單元的組成部件就減少了。這樣就將簡化輪轂單元的結(jié)構(gòu),改善它的可靠性,減少制造成本。這樣設(shè)計的一個理由是輪轂單元的危險點(diǎn)并不是上緊位置而是帶凸緣的內(nèi)圈的根部。另一個是通過FEM分析獲悉小內(nèi)圈在轉(zhuǎn)動過程中受到的不是很重的軸向載荷。所以小內(nèi)圈可以省略。不過在開展這項項目之前仍在在實踐中,關(guān)鍵問題比如滾動體的裝配,模鍛軸承溝的精確尺寸,在重載荷下的塑性變形必須解決。
參考文獻(xiàn)
[1] Junshi.Sakamoto.輪轂單元軸承的發(fā)展趨勢和新工藝.運(yùn)動&控制,2005(17):2~9
[2]T.NUMATA.汽車車輪軸承的技術(shù)動向.KOYO英文版工程雜志,2003(162E):32~36
[3] Hirohide Ishida, Takeyasu Kaneko.輪轂單元軸承的模鍛發(fā)展. 運(yùn)動&控制. 2001(10):9~14
[4] K.TODA,T.ISHII,S.KASHIWAGI,T.MITARAI.應(yīng)用于汽車車輪軸承上的軸釘牢輪轂單元的發(fā)展,KOYO英文版工程雜志. 2001 (158):26~30
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