The 3 Speed Transmission is a performance bolt on to existing small engine Honda clones. Since a transmission has yet to be introduced, these engines are limited to single speed gearing. Which ultimately restricts the performance of the small engine vehicle. It’s a trade-off, high top speed and slow acceleration, or low top speed and fast acceleration; with a transmission there’s no need to choose. Similar to a manual transmission in a car, an input, counter, and output shaft are used with a constant mesh transmission to create different gear ratios.
Proof of Concept
The main industry this product impacts would be child-sized and cheap recreational vehicles. The main torque converter used in this industry are less effective CVT transmissions that use weighted rollers to chain the gear ratios. This new, gear driven, transmission would revolutionize the application of small displacement engines. The main concern for this transmission would be cost. These engines as a whole is quite inexpensive as a whole, so manufacturing cost will be essential to our selling point. These engines have a wide range of applications, so even existing products will be potential consumers.
Team 14’s concept shows how the transmission will function, by demonstrating just one of the gear shifts within the transmission. If Team 14 can prove the function of one shift, Team 14 will be able to replicate this across multiple gear ratios. The team will prove the ability to shift gears and its ability to function through a dog clutch design. Team 14 will also prove its small size and ability to be installed easily to the widely popular Honda Clone engine. Note that solidworks gear library only limits to gears with size of 10 teeth or more, however Team 14 needs a gear of 7 teeth. The balloon 4 (Left) represents the actual gear that needs to have 10 teeth, while 4 (Right) is theoretical, as the gear has 7 in reality but on limited to 10 in solidworks.
SHIFT3R is a 3 speed transmission designed to me easily mated to any Honda clone, the most common being the predator 212cc engine. Ideally, Team 14 is hoping to make it cost under 600 dollars. It will be competing with the CVT since they are both transmissions, however, SHIFT3R offers a new alternative to higher performance. CVTs are limited in design, and a three speed transmission widens the gear ratios more than a CVT ever could. Also it needs to be light, preferably under 20 pounds. Aluminum casing is used to keep weight low, all internal parts are steel. Go karts and other vehicles want a lighter vehicle for higher performance so weight is heavily considered. The shifting mechanism also has to be able to be placed in a small range of areas to accommodate different vehicles. The shifting mechanism is designed with this in mind. The outer casing needs to be 0.25 inches in thickness all the way around in case anything spinning at high rpm fails. Paint on the casing must also be safe for use. The transmission will be lubricated with oil at the bottom which will be picked up by the gears to ensure moving parts work well and temperatures remain safe. All these parts will be painted or designed to be resistant to rust and corrosion. Packaging must be strong enough to not damage the transmission, most likely shipped in a small wooden container. Instructions on how to install on engine, recycling and disposal, and lubrications will be posted within the packaging. It is expected to last around 10,000 miles, and be inoperable with the casing open.
The purpose of this project is to revolutionize the go kart and small vehicle industry. People interested in these small vehicles have an affinity for working with their hands, performance, and just like the fun factor of owning one. These vast majority of these vehicles use the same Honda clone engine with its wide variety of aftermarket parts. A transmission is the next stepping stone in performance. These vehicles use single speed designs and CVTs to achieve their best speed and torque ratios. A transmission can achieve both of these at the same time, and at the users command. The user can now take off from a stop faster, and have a higher top speed. Most vehicles run a 5:1 or 6:1 gear ratio, and for example, let’s say that has a top speed of 29 and 24 mph respectively. SHIFT3R is creating a transmission with gear ratios, 5.4, 3.24, and 2.4, in order. Using all the same specifications, this makes taking off just as easy on the transmission, and the new mechanical top speed 65 mph. In addition, the output shaft of the transmission is mated to the axle by centrifugal clutch and chain just like a traditional go kart, which can be played with to achieve different final drive ratios. This transmission will accomplish high torque output as well as generating a higher top speed to unlock more potential out of these small vehicles.\
The parts that need to be manufactured are; case, forks, drum, shaft, and gears. Currently all major parts of the fabrications are completed that Team 14 was in charge of, which is forks and case. The shaft and gears are being machined by Brian and are expected to be completed by the end of the upcoming week. The drum is an extra part of the assembly to make the shifting mechanism easier. However after talking to our mentor (Maus), it was decided that our project will still pass the go-no-go criteria without the drum. The case in Fig. 1 shows the cut out of the case and is cut slightly larger in case the gears or shaft come back with different dimensions. Also, the forks in Fig. 3 are cut at unusual angles to accommodate the shifting drum if we can get it manufactured in time. Currently one of our team makes is going over our drum to get it manufactured and should be finalized by the end of next week. Once the verdict on the drum gets decided, then the normal assembly can be done. However, if the drum isn’t used then the assembly can still be completed without. The pieces in Fig. 4 will be fitted in to the drum. Then when all the pieces are back, the shafts and gears will be measured to see if they are within spec. If they are the extra material will be taken off the case and assembled as expected.
Fig. 1 The pieces of the case cut out
Fig. 2 One of the completed plasma cut forks
Fig. 3 The second fork before it will be welded together
Fig. 4 Cam (left) to be press fit on the shaft of the drum with the 6 rods to engage the gears. A single spring will be used to hold the shifting mechanism in place.
Testing and Results
Meet the Team
Carlos is a senior engineering student at the University of Nevada, Reno, originally from Las Vegas, Nevada. The most challenging engineering project he worked on was building the 3D Printer. Needing constant testing and improvements, it really tested Carlos’ abilities. Carlos has learned to apply his engineering education to his everyday engineering projects. He also learned the business and entrepreneurship skills from Make48 and his engineering entrepreneurship class. Carlos’ proudest creation was his homemade drift trike powered by a 197cc Honda clone engine. With a 6:1 gear ratio, it was obvious the gearing was too high to run at cruising speeds. Since then, Carlos has been interested in creating the first bolt on transmission for these engines. Goals now are to graduate, design and build race cars. Carlos wants to restore his Camaro, and build the perfect high power pro-touring race car.
Jose is graduating in the spring with a mechanical engineering degree. He’s originally from Las Vegas, Nevada and moved to Reno in 2015 for college. Some of his short term goals include graduating and doing well in this class. Some of his long term goals include going into aviation and aeronautical industry. One of the most challenging engineering project that Jose encountered was the statics bridge. It wasn’t hard to build but hard to calculate all the forces beforehand to make sure it could withstand the weight. A proud accomplishment of jose is the fidget spinner. This was because it was before fidget spinners took off like crazy, so it was like we started the trend.
Sierra is originally from South Lake Tahoe and came to the University of Nevada, Reno in 2014 to study Business Management. After a year in business she switch into engineering. As an engineering student, Sierra was exposed to a number of projects that have challenged her and taught her a number of new skills. The most challenging project she has worked on was the hovercraft project assigned during her first semester. During the project, two of her teammates abandoned the team leaving the rest of the team short handed. The work the remaining members had to put into the project was extensive, but they were able to pull off a unique and successful end product. Outside of school, Sierra is a part-time manager at Beach Hut Deli and will be starting an internship working for EM Research towards the end of November. After graduating Sierra hopes to explore more engineering opportunities outside of Nevada or possibly outside of the United States.
Tyler is a senior mechanical engineering student at the University of Nevada. Tyler graduated high school in 2011 and started an economics degree at UNR. After two years, Tyler started working full time for an insurance company. Tyler decided to come back to school in 2015 to pursue a mechanical engineering degree. Tyler has since been a part of ARLISS and NSat, autonomous drone clubs at unr, and continues to work on his street bike.
Joshua is also a senior at UNR who was born and raised in Reno, Nevada. Graduating in the spring with a bachelor’s degree in mechanical engineering as well as an associates degree in business administration. Along with school, Joshua takes on a full-time lead position at GSR and oversees ten employees. Engineering accomplishments include hovercraft, static bridge, and CSWA certification, with the freshman year hovercraft project being the most challenging engineering project. The hovercraft and static bridge, along with several group projects, have developed problem solving skills that will carry over to a professional career. Short-term future plans are to build a pulse jet, other short term goals involve leaving GSR and starting an engineering internship in an attempt to transfer into a more serious engineering job. Long-term plans involve getting a successful job with an engineering firm and trying to engineer a better future. Also engineering an off the grid RV to live in full time and travel across the US taking up different engineering related jobs.