折叠式自行车的整体设计7张CAD图
折叠式自行车的整体设计7张CAD图,折叠式,自行车,整体,设计,CAD
附录一：
文章编号:1006-2343(2014)06-161-05
一种新型无链折叠式自行车的数字化设计
闻霞 1，2，曾镇清 3(1．三明学院机电工程学院，福建三明 365004， E-mail:wenxia_wen@163．com;2．三明机械 CAD 工程研究中心，福建三明
365000;3．福建西河卫浴科技有限公司，福建泉州 510641)
选段：
自从进入 21 世纪以来，随着我国社会现代化的发展，摩托车、小轿车等交通工具进入人们的生活，自行车似乎突然淡出了人们的视野。然而，近几年来随着我国经济的快速发展和城市化进程的加快，私家车大量涌现而引发城市交通拥挤、喧嚣、空气污染、自驾车引起的颈椎病等问题，快节奏的生活更是让人们缺乏运动机会，人们的生活理念也随之发生了变化，低碳环保、绿色健康成为人们向往的生活。无链折叠式自行车因其环保、健身、娱乐及便捷等优点再次受到人们的青睐。新型无链折叠式自行车是随着现代都市生活理念变化而设计的一种集绿色环保、健身、娱乐、时尚、便捷、轻巧等特点为一体的新型交通工具。设计理念跟随时代的人性化设计，赋予美感、时尚、充满情趣和活力，其设计的核心是“以人为本”，自行车设计、优化成为永恒的主题。
1 无链折叠自行车的诞生及发展现状
1.1 自行车的诞生及发展
1818 年年轻的德国替林人德莱斯首创了前轮可以转向的自行车。1858 年苏格兰的邓洛普研制将充气轮胎用于自行车，使自行车减振性能大大增强，让骑车人的骑行舒适度更为提高。再加上管材结构，配上车铃、支架、车灯等部件，前后轮改为一样大，到 19 世纪末自行车结构就基本完善了［3］。自行车开始通过批量化生产逐渐走进普通人的生活，成为人们生活中方便、快捷的代步工具。随着人们生活水平的提高，绿色健康与低碳环保意识的增强，自行车不会因为新型机动车
交通工具的发展而减少。但是现在的城市交通拥挤、存车处面积明显不足，机动车的停放已被公认为全球性的难题，而在我国，比机动车停放更难的是自行车的停放问题［4］。市内各街道、人行道占用停车的情况严重，自行车被盗现象十分普遍。结构简单、轻巧快捷、携带方便的折叠自行车可以很好地解决这些问题。
1.2 自行车的传动机构的发展变化
自行车自问世以来，主要釆用的传动机构主要是链轮和齿轮传动机构等。这些传动机构的结构和性能限制了自行车的使用性能和力的转换效率的进一步提高， 自行车的传动机构已成为人力自行车性能提高的主要技术瓶颈［5］。链式传动，具有制造简单，安装、维修以及更换方便等优点，但是链式传动存在容易玷污衣物、脱链、传动效率不高等缺点，而且链式传动结构需要占用空间大，质量偏重， 不符合轻便、结构紧凑、便于折叠等问题。2005 年北京乔特自行车有限公司经过多年开发，向市场推出了一种荣获国家专利发明权的无链杠杆传动自行车［6］，与链式传动方式相同的圆周式运动，占用空间偏大。2012 年由阚海辉设计的变速锥齿轮无链自行车［7］，并申请了国家专利，实现了无链式传动，但该设计仅对原有链式自行车的改造。2009 年淮阴工学院机械工程系的卜云峰等人设计一款四连杠杆式传动机构无链式自行车［5］，应用杠杆原理和齿轮传动原理，结合四连杆运动轨迹有效加长运动过程中杠杆的力臂长度、增大对顶角，提高了能量转换效率。但结构较复杂，其传动机构不适合于折叠自行车的设计。
2 新型无链折叠式自行车设计理念
2.1 新型无链传动结构紧凑、轻巧针对目前自行车传动结构的现状，为折叠自行车设计需要，研发一款棘轮式无链传动机构自行车，避免了传统无链杠杆式传动，结构紧凑，适合轻便、折叠的特点，其传动原理在传动机构设计中有详细的阐述。
2.2 具有良好的减振性能的设计结构人性化的设计重点是舒适性，在自行车支架上连杆设计为弹簧支架实现了行进过程中弹性缓冲，极大的改善了骑车的舒适度，弹簧支架的设计结构。
2.3 传动装置采用棘轮式无链传动机构，结构紧凑，便于折叠传统链式自行车链传动由链轮、链条及飞轮三部分组成，其不足之处在于:①骑行过程中会出线脱链、断链、夹裤、润滑油横流污衣裤等现象，②采用链罩，链条如从链轮或飞轮上滑下时，重新安装很困难。③链轮直径较大，导致链传动机构体积大，结构不
够紧凑，外形不美观，对折叠结构的设计带来困难。
该款新型折叠无链式自行车采用棘轮式传动，机构集中在后轮部分采用两个棘轮、四个锥齿轮啮合实现异步运动及脚踏往复运动实现传动，后轮设计较大，而前轮直径设计较小，因此使得整车体积小，结构紧凑，便于折叠。
2.4 充分选用应用新型材料，质量轻
运用数据挖掘的原理［8］，确定自行车车架结构部件主要尺寸，改进车架材料，可采用铝合金、钛合金、镁合金、碳纤维等，使得车架质量更轻，强度更高。在新工艺技术方面，主要研究方向是使用最少的材料，实现更高的机械强度，例如， 使用可变截面的管材和板材替换原来同一界面的材料，使得自行车性能更加可靠， 使用材料更少。
该款新型折叠无链式自行车车架的设计采用铝合金 6061T6 材料，铝合金具有质量轻，可塑性好，刚性高，高抗氧化等优点，虽然造价会比起传统的高碳钢车架昂贵，但是在制造车架的形状上有很大的变化空间，可以通过软件优化算法实现数字化的设计，最优化来节约制造成本。
2.5 设计折叠过程简单，快捷，便于携带
折叠或打开需要合理设计产品的形态，以期能够更好的实现它的设计诉求。在折叠式自行车的设计过程当中，尽量将一个折叠自行车设计成一个规整的造型， 努力将它的传动装置通过折叠后能隐藏在内部，这样的设计不仅满足了美学上的需求，同时这样的造型更易于携带。该款无链折叠自行车的设计充分体现人性化， 简单便捷，折叠时间应在十几秒钟内完成，否则将会失去普及性和实用性。
3 整车结构数字化的设计实现
数字化设计是一种先进的设计思想，也是集各种优秀设计工具为一体的设计平台［9］。利用 iNPD(integrated New Product Development)技术的工业设计方法实现该款新型无链折叠自行车的设计。
3.1 新型无链折叠式传动机构设计该款新型无链式折叠自行车后轮传动机构采用两个棘轮、棘爪、小棘爪、棘轮轴、轴承及踏杆曲柄主要部件实现传动，其后轮机构传动原理简图如图 5 所示，其爪转动机构带动后轮轴旋转，由于后轮轴与后轮为刚性联接，因而实现后轮的转动。棘轮(如图 3 所示结构)环内的棘齿可实现单方向传动，内部采用 4 个锥齿轮相互啮合实现异步传动。同时通过内部锥齿轮相互啮合传动转换实现踏杆曲柄的异步动作，自运动原理:由脚踏上下往复运动
带动棘轮转动，棘轮通过棘行车运动的速度由脚踏杆抬起最大的角度、轮毂的半径及往复一次循环所用时间等因素决定，采用碟刹装置实现刹车，制动效果较好， 制动时，摩擦制动块 16 加紧后刹车片 15 实现后刹车片制动，而后刹车片与后轮毂及轴套是刚性连接，从而实现后轮刹车制动。
3.2 新型无链折叠式自行车折叠方式的设计目前常用的折叠自行车的分类方式可以分为:①车架大梁折叠式(对折式)，②前后叉折叠式③坐管车架折叠式④异形车架折叠式⑤A－BIKE 折叠式叠等几种折叠方式［11］。该款折叠无链式自行车的设计偏重于前后叉折叠式，保留了轮子的拖动功能;在车架杆的下方设计弹簧支架的减振装置尺寸较短，便于折叠，刚性弹簧起到缓冲作用，增加骑车的舒适性;并综合考虑了满足合理结构、时尚外观、折叠方便、携带便捷等综合因素，适合出现在地铁、办公场所、校园等场合。
该款折叠无链式自行车折叠步骤主要分为:①前杆 4 设计为可伸缩杆，折叠时先向下收缩变短，然后绕车架杆 1 和车架 6 连接处向下旋转至使前杆 4 与车架 6 相平齐，使得小轮正好位于大轮的正上方;②车座旋转与车座杆 9 成直线，然后一起旋转进入车架杆 1 中，完成折叠。折叠方式既保留了大轮子的拖动功能，而且还保留的把手在最上方使用功能。折叠步骤简单，巧妙，体积不到原来的 1/3。
折叠自行车的 创新设计与研究
文｜匡焱
（黄冈职业技术学院 黄冈 438002）
选段：
1 折叠自行车的起源和发展
折叠自行车是 20 世纪 30 年代在欧洲起源于军事用途，并伴随着轿车的普及和城 市人口的增多而发展起来的。近些年由于采用各种新材料、新技术及结构创新，从而 使体积更小、重量更轻、更结实耐用 [2]。
目前，市场上出售的自行车品种繁多，如公路自行车、山地自行车、 旅游自行车等， 众多的自行车都存在一个明显的问题，就是携带非常不方便，这无疑给使用者带来麻烦， 尤其是在这个高速发展的时代。因此，人们迫切需要一种结构简单，使用灵活，便于 储放的交通工具。
自行车的发展方向是设计轻量化、个性化、功能化、方便化、款式多样化 , 自行 车系列产品将得到更迅速的发展 , 并形成高、中、低多档次格局 , 尤其折叠自行车是我 国最具潜力并取得世界领先水平的产品。一般折叠车有车架折叠关节和立管折叠关节 构成，通过车架折叠，将前后两轮对折在一起，可减少45% 左右的长度。整车在折叠 后可放入登机箱和折叠包内，以及汽车的后备箱内。在折叠的使用过程中也不需要借助外来工具，可通过手动自行将车折叠展开， 自行折叠。在折叠后，通过座杆为支撑点使车能立稳。折叠自行车携带和使用方便舒适，开发形成系列产品后, 极具潜力。
2 折叠自行车的优点
自行车作为短途代步工具，具备其他交通工具不可替代的功能，而折叠自行车则比自行车具有更多的优点。
优点：
1） 寿命长。自行车放在室外日晒雨淋，车体老化严重，放在公共场所被盗令人十分头疼。当拥有折叠自行车后，可以方便的把折叠自行车放在家里、办公室、汽车后备箱里，不用担心被风吹日晒雨淋而减少它的使用寿命。
2） 体积小，便于储藏。折叠自行车通过折叠，前轮和后轮折叠在一起，可以减少 50%左右的长度，便于携带、收藏，还能防盗。
3） 实用便捷。折叠自行车集交通、休闲、运动于一体。可作交通工具出行，可放置在汽车后备箱里，郊游时既可享受汽车的便利，在郊外又可骑行享受田园风光的乐趣。
4） 骑乘轻松，简单易调，男女老少皆宜。
5） 健康环保。不会像汽车一样使用不可再生资源，折叠式自行车对空气无污染。同时现在的人们缺乏锻炼，骑自行车可以适当锻炼身体。
6） 时尚浪漫。折叠式自行车色彩明亮，具有视觉冲击感，而且比一般自行车轻，提上楼、上电梯、上公车、乘地铁, 都不费劲, 是公共交通的最佳伴侣。
3 折叠自行车的设计方向
一个好的折叠自行车对设计和加工工艺上的要求会高于普通的两轮自行车，所要权衡的因素和达到的要求也很多，以下是重点考虑的几点：
1） 质量轻，体积小，节省体力。
2） 材料的力学性能要好，不怕被挤压，这是为了将折叠自行车放置在轿车车厢内，折叠自行车它上面会搁置其它的物品，不会因为重压而使自行车变形。
3） 骑行舒适，调整范围大，可适合不同人群。
4） 骑行速度快。要求它的传动变速比和大众化自行车相差
5） 折叠、展开方便快捷。无须太用力，即可在十几秒到一分钟内实现展开折叠。折叠车在随身携带过程中，要保证它的折叠和展开能够快速完成，来保障骑乘者在不同路段对折叠车的折叠和展开顺利进行。
6） 安全系数要求高。具有稳定性能，对锁紧装置要求高。
7） 外观时尚。
4 折叠自行车的设计方案
自从折叠自行车发明以来，就有人不断尝试把折叠自行车弄得更小一些，占用空间更少一些。各种形式的折叠自行车层出不穷，剖其究竟，广泛的折叠方式是将大梁折叠或收缩，将前后轮折叠在一起，将车座降低，车把侧放。这种方式虽
然实现了折叠，减小了车体面积。但是不足之处显而易见，这种设计折叠效果不佳，并且需要拖行，携带不便，对于折叠车来说，意义不大。
而这次创新型自行车大胆的设计成单前叉，为前轮创造折叠环境。车把和竖杆的折叠有效的减小了车体折叠后占地空间，前后轮折叠安放在月牙形车身内完成三环重合的折叠效果。它是一种构思新颖，结构简洁独特，能够单人折叠和展开， 携带和使用方便的三圆（前车轮、后车轮、呈月牙形半圆的车身架）折叠自行车。
5 市场前景
随着人们生活水平的提高, 健康与环保意识的增强, 自行车不会因为其它交通工具的发展而减少。自行车作为短途代步工具，具备其他交通工具不可替代的功能。它成为上班族、学生、有车族、老年人的时尚选择，将会带来良好的社会效益和经济效益[3] 。而根据发达国家自行车发展的经验来看，我国正处于经济高速发展和轿车开始大量进入家庭阶段，自行车产业也即将迎来发展变革的机遇， 折叠自行车则以其独特的优点，符合我国未来交通发展的需求，以此看来，折叠自行车在我国的前景十分广阔。
附录二：
Article ID: 1006-2343 (2014) 06-161-05
A new digital design chainless folding bike
. Wen Xia 1,2, the town was clear 3 (1 School of Mechanical and Electrical Engineering College, Sanming, Fujian Sanming 365004, E-mail: wenxia_wen@163.com; 2 Sanming Mechanical CAD Engineering Research Center, Fujian Sanming 365000; 3 Fujian River sanitary technology. Ltd., Quanzhou, Fujian 510641)
Excerpts:
Since entering the 21st century, with the development of China's social modernization, motorcycles, cars and other vehicles into people's lives, bike suddenly seemed to fade out of people's vision. However, in recent years, with the acceleration of the rapid development of China's economy and the urbanization process, the car caused large numbers of urban traffic congestion, noise, air pollution, caused cervical disease self-driving and other issues, life is so fast-paced lack of exercise opportunities for people, people's life philosophy also will change, low carbon environmental protection, green and healthy living people aspire to become. Chainless folding bike because of its environmental, health, entertainment and convenience advantages again by people of all ages. The new chainless folding bike with the idea of change in modern urban life and design a set of green, fitness, entertainment, fashion, convenient, lightweight and features for the new vehicle integration. Follow humanized design concept of the times, giving beauty, fashion, full of fun and energy, the core of its design is the
"people-oriented", bike design, optimization has become an eternal theme.
1 The birth and development of the status quo a chainless folding bike
1.1 Birth and development of the bicycle
1818 young German for Lin Rende Royce pioneered bicycle front wheel can turn.
1858 Scotland Dunlop developed the pneumatic tires for bicycles, bicycle greatly enhanced damping performance, so that the rider's ride comfort is more improved. Coupled with the pipe structure, coupled with bell, stand, lights and other components, front and rear wheels to as large as the 19th century structure on the basic sound of the bike [3]. Cycling into the lives of ordinary people began through mass production, people's lives convenient, fast means of transport. As people's living standards improve, and enhance the health of low-carbon green environmental awareness, because the development of the new bike is not a motor vehicle transport is reduced. But now the urban traffic congestion, parking lot at the area is obviously insufficient, parked vehicle has been recognized as a global problem, but in our country, harder than the vehicle is parked bicycles parked problem [4]. The city's streets, sidewalks occupied parking situation is serious, bike theft is widespread. Simple structure, lightweight, fast, portable folding bike can be a good solution to these problems.
1.2 Developments and changes in the transmission mechanism bike
Since the advent of the bicycle, preclude the use of the main transmission mechanism is mainly sprocket and gear agencies. Structure and properties of these drive mechanism limits further improve the conversion efficiency of the bicycle performance and power, the bicycle transmission mechanism to improve the performance of the bicycle has become a major human bottleneck [5]. Chain drive, with a simple to manufacture, installation, maintenance and easy to replace, etc., but the presence of a chain drive easily tarnish clothing, take off the chain, the transmission efficiency is not high shortcomings, and chain transmission structure requires a large space, quality emphasis, does not meet the Lightweight, compact, easy to fold and other issues. Choate 2005 Beijing Bicycle Co., Ltd. After years of development, to market an invention won the national patent rights chainless bicycle gear lever [6], with the same chain of drive-in motion circumference, space is too large. 2012 designed by Kan Fai chainless bicycle gear bevel gear [7], and the national patent applications, achieved without chain drive, but only for the transformation of the original design of the bicycle chain. 2009 Bo Yunfeng Huaiyin Institute of Technology Department of Mechanical Engineering, who designed a four with no chain drive mechanism leveraged bike [5], the application of the principles of leverage and gearing, combined with a four-link trajectory effectively
lengthen the process of movement of the lever arm length, the vertical angle is increased, improving the energy conversion efficiency. However, more complex structure, the transmission mechanism is not suitable for folding bike design.
2 The new chainless folding bike design
The new 2.1-free chain drive is compact and lightweight for the current status of the bicycle transmission structure for folding bike design needs, developing a ratchet-free bicycle chain drive mechanism, to avoid the traditional leveraged chainless drive, compact, lightweight fit folding characteristics of its transmission principle have been elaborated in the transmission mechanism design.
2.2 has good damping properties of the design structure of human design focus is on comfort on the bike stand rod bracket is designed to realize the process of moving the spring elastic buffer, greatly improved ride comfort, design structure of the spring bracket.
2.3 gear Ratchet-free chain drive mechanism, compact, easy folding bicycle chain drive from the traditional chain sprockets, chains and flywheel consists of three parts, its disadvantage is that: ① riding off the chain process will qualify , chain scission, clip pants, dirty underwear lubricant cross-flow phenomena, ② using chain cover, such as when you slide down the chain from the sprocket or flywheel, reinstall very difficult.
③ larger diameter sprockets, chain drive mechanism resulting in large volume, structure compact enough unsightly appearance of the folded structure design difficult.
The new folding bike which uses no chain drive ratchet, concentrated in the rear part of the body using two ratchet, four bevel gears and pedal asynchronous reciprocating movement to achieve transmission, rear-wheel design large, and the front wheel diameter design smaller, thus making the vehicle is small, compact and easy to fold.
2.4 full selection of application of new materials, light weight
Use of data mining principles [8], to determine the size of the main structural member of the bicycle frame, the frame material is improved, can be aluminum, titanium, magnesium alloy, carbon fiber, etc., so that the carriage lighter, higher strength. In the new technology, the main research direction is to use the least amount of material to achieve a higher mechanical strength, for example, using a variable cross-section of the pipe and sheet material to replace the original one interface, making the bike more reliable, less use of materials.
Which novel non-chain folding bicycle frame design made of aluminum alloy 6061T6 materials, aluminum light weight, plasticity, high rigidity, high resistance to oxidation, and other advantages, although the cost will be compared to traditional high-carbon steel frame is expensive, However, the manufacture of the frame in the shape of a great change in the space can be optimized algorithm by digital design software, optimized to save manufacturing costs.
2.5 Design of the folding process is simple, fast, easy to carry
Folded or unfolded form needs rational design of products in order to better achieve its design appeal. In the folding bike design process, as a folding bike designed as a structured shape, efforts by its gearing folded can hide inside, this design not only meet the needs of aesthetics, while this shape easier to carry. Which chainless folding bike design fully reflects humane, simple and convenient, folding time should be completed within ten seconds, otherwise it will lose popularity and practicality.
3 vehicle structural design and implementation of digital
Digital design is an advanced design ideas, but also set a variety of excellent design tools for the integration of design platform [9]. Industrial design approach iNPD (integrated New Product Development) technologies which achieve the new chainless folding bike design.
3.1 The new chainless folding mechanism design which drive new non-folding bike rear chain drive mechanism uses two ratchet pawl, a small ratchet, ratchet shaft, bearings and crank pedal lever to achieve the main components of the drive, then wheel mechanism driving principle diagram shown in Figure 5, after its claw rotating shaft rotating drive mechanism, since the rear axle and rear rigid connection, thereby achieving rotate the rear wheel. Ratchet ratchet ring gear can be achieved in one direction (the structure shown in Figure 3), the internal use of four bevel gears meshing with each other to achieve asynchronous transmission. While meshing with each other through an internal bevel gear drive conversion kick lever crank achieve asynchronous operation, since the principle of movement: by foot and down reciprocating ratchet drive rotation speed ratchet spine through traffic movement by foot lever to lift the maximum angle, wheel radius and reciprocating with a cycle time and other factors, the use of disc brakes device to achieve, better braking, braking, friction brake pads 16 after 15 after stepping achieve brakes brakes brake, brake pads and then after wheels and bushings are rigidly connected, enabling the rear brake.
3.2 Design of new chainless folding bike folding methods currently used classification folding bike can be divided into: ① folding frame rails (to fold), front and rear folding fork ② ③ ④ folding seat tube shaped frame Folding frame ⑤
A-BIKE folding stack, such as several folding [11]. Which no chain folding bike design
emphasis on folding front fork, retain the wheels dragging; the shorter the frame at the bottom of the rod holder design spring damping device size, easy to fold, the rigidity of the spring cushion increase ride comfort; and considering a combination of factors to meet the reasonable structure, stylish appearance, easy to fold, easy to carry, suitable appeared in the subway, office, campus and other occasions.
Which no chain folding bike folding steps are divided into: ① before lever 4 is designed to be telescopic pole, the first contraction shorter when folded down, and then around the frame and the frame 6 bar one junction down before rotating to 4 and 6 pole flush with the frame, making the ferry is located just above the large round; ② rotating seat and seat post 9 in a straight line, and then rotated into the frame along with a bar, a complete folding. Folding only retains the big wheels drag function, but also to retain the use of the function at the top of the handle. Folding step is simple, clever, less than 1/3 of the original volume.
Folding bike
Innovative Design and Research
Man | Peter Yan
(Huanggang Polytechnic College Huanggang 438002)
Excerpts:
1 Origin and development of a folding bike
Folding bikes are in the 1930s in Europe originated in military use, along with an increase in the popularity of cars and urban population and developed. In recent years due to the use of a variety of new materials, new technologies and structural innovation, so that smaller, lighter, more durable [2].
Currently, the market selling a wide variety of bicycles, such as road cycling, mountain biking,? Bicycle tour, many of the bikes are an obvious problem, is very inconvenient to carry, which will undoubtedly bring trouble to the user, especially in the The rapid development of the times. Therefore, there is an urgent need for a simple, flexible, easy to store transport.
The development direction of the bike is lightweight design, personalized, functional, easy-oriented, style diversification? Bike series will be more rapid development? And the formation of high, medium and low-grade multi-pattern,? Especially folding bike Our most potential and achieve world-leading products. Generally there are folding folding frame folding riser joints and joint configuration, by folding frame, the front folded two rounds together, can reduce the length of about 45%. After folding the vehicle chassis and the board can be placed inside the folded package, as well as inside the trunk of the car. In the folding process of using external tools do not need the help, self-Deployable car by hand, self-folding. After folding, for the support to make the car can stand steady through the seatpost. Folding bike comfortable to carry and easy to use, after a series of products developed? Great potential.
Advantage 2 folding bike
As a short bike means of transport, with other modes of transport irreplaceable function, and folding bike is more advantageous than a bicycle.
Benefits:
1) long life. Cycling on the outdoor sun and rain, severe aging body, it is placed in a public place is a big headache. When they have folding bikes, folding bikes can easily at home, office, car trunk, do not worry about the wind and sun and rain to reduce its service life.
2) Small size, easy to store. By folding folding folding bike, front and rear wheels together, you can reduce the length of about 50%, portable, collection, but also security.
3) practical and convenient. Folding bike set transportation, recreation, sports in one.
Can be used for transport trips, can be placed in a car trunk, can enjoy the convenience of the car when the outing, on the outskirts of the idyllic but also enjoy the fun of riding.
4) riding easy, simple and easy to adjust, men and women ages.
5) environmental health. Like a car does not use non-renewable resources, foldable bicycles on air pollution. Now people while lack of exercise, exercise bike can be appropriate.
6) romantic fashion. Folding bike with bright colors, with a sense of visual impact, but also lighter than the average bike, put upstairs, on the elevator, on the bus, subway,? Not strenuous,? Is the perfect companion for public transport.
3 folding bike design direction
A good folding bike design and processing requirements will be higher than normal on the two-wheeled bike, you want to weigh the factors and requirements to achieve a lot, the following are important considerations in mind:
1) ? Light weight, small size, saving energy.
2) ? The mechanical properties of the material better, afraid of being squeezed, which is to be placed in the car folding bike car, folding bike on it will hold other items, will not be leaving because of the weight of the bicycle deformation.
3) ride comfort, large adjustment range, may be suitable for di
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