Design Preview Report: Miata Cup Holder

For my project I have decided to make an alternative cup holder for my Miata. The reason for this is due to the annoying reality of my illogical cup holders. I continually hit my elbow on any cup that’s in my cup holder when shifting gears but also, the cup holders are not large enough to fit my water bottle. So I have come up with a design that should help deal with the situation. An example of this issue is shown below which I have borrowed from my post 6.

In this photo, you can see where the cup is in relation to the shift knob. As you can see, this is in the direct path of where my arm should be. So, what if I want a tasty beverage while I’m shifting into third shooting up a canyon road? Well I present to you, MX-5 Cup Holder V1.

I have a few specifications that I need to meet for this product to be a success in my eyes. These are described below.

The design needs to look like it’s an OEM (Original Equipment Manufacturer) piece. This means that the design looks like it’s something you can purchase from the Mazda factory as an option on the car.

The design needs to fit onto the car without any need for additional modifications to the original car design. This means that the design shouldn’t require me to cut, damage or modify any of the existing aspects of the car.

The design needs to be able to accommodate multiple cups, bottles and other items. I would like to be able to use the cupholder for not only my water bottle but other items as an extra storage piece which allows for an additional “dynamic” portion of the project.

The design also needs to be able to support adequate weight. This will be decided through testing but a full metal water bottle can be quite heavy, so I want the design to be able to support this.

The design also needs to be able to hold in place under motion. I wouldn’t want whatever is housed in the holder to fall out when turning or accelerating.

The design needs to be able to be easily accessible when driving. The holder cannot be too strong to where it’s difficult to remove the object while driving but also difficult to place the object back into the holder as well.

Lastly, The design also needs to be dynamic in one shape or another. Although this is a requirement of the class, it still needs to be accomplished. Right now, I am still thinking of ways to achieve this but allowing for multiple items to be held in the holder will have to suffice for the time being.

To meet these requirements, I have come up with a few sketches for an idea that could be implemented as the final design as shown below.

As you can see this design will borrow inspiration from an example I found in my inspiration post. This design will include the components listed below including their functionality.

4 springs

•   two springs for closing the claws that are used to close onto the bottle
• one spring for flipping the claws up in to the horizontal position when opened
• Lastly, one spring for the support base that will be used to hold the weight of the object in the cup holder itself

Claws

• The claws will be two separate pieces that are used to hold the object or cup in the upright position and preventing it from slipping out of the holder when turning.
• This will be manufactured using a 3d printer using silver PLA material for strength and to match the color of the interior of the car

Base

• The base as mentioned will be used to support the weight of the object or cup that is placed in the holder
• I would like to add the ability to flip the base into the upright position with the claws to stow the cup holder when not in use which will allow for a more dynamic design
• This will be manufactured using a 3d printer using black PLA material for strength and to match the color of the interior of the car

Button Release

• The button release will be used to release the spring on the base allowing the base to flip down and the claws to flip up essentially opening the cup holder for use.
• I haven’t completely designed this addition yet but it will likely be done using silver PLA and 3D printed with the claws

Back Plate

• This is the bread and butter of the design. This will act as the frame to support all of the components and the object itself. This will also be the component that will be fastened to the vehicle via the screw hole on the side of the transmission tunnel
• This will be manufactured using a 3d printer using black PLA material for strength and to match the color of the interior of the car

OEM Screw

• This is the only piece that I am using from the car. It’s a screw that holds the plastic interior panels onto the transmission tunnel. It’s a very basic screw but through research, I have confirmed that this will be able to hold the back plate in position

Hinge

• I have debated adding a store-bought hinge to the base allowing it to flip up and down but I think I should be able to design a 3D printed hinge in SolidWorks or use a small shaft with through holes on the base and back plate.

Timeline

03/07/24

• Brainstorm
• Sketches

03/14/24

• CAD Modeling
• Spring and Hinge Sourcing as well as other materials

03/22/24

• 3D printing (this will take some time to get the dimensions right and will likely take a few prints)

03/30/24

• surface finishing

03/31/24

• Documentation

04/05/24

• Install

I did leave some time for errors in virtual assembly and extra time for 3D printing.

Fabrication

3D printed parts will have time estimates based off the STL file and if this takes too long my plan is to utilize the Idea Forge 3D printers

Surface finishing will include remove supports, filing of critical components (Hinges, springs and button release). I might use iso alcohol to remove print lines, but this is up to the surface finish result.

Assembly and install should be relatively painless and I am designing components to be snap fit with the use of basic hand tools.

I can imagine that this design will have multiple iterations. This is due to the fact that I have very little 3D printing experience. I can imagine that some designs might not be possible to do on a 3D printer so I will have to practice some of my design for manufacturing skills. I am planning to purchase a cupholder and remove some of the components to acquire the springs which could take some time. This is because it’s not exactly easy to find small purpose-built springs for this application. Implementing these springs into my design that will also require me to 3d print the design will be difficult as one can imagine so there is a possibility I might look into going with another idea.

The other Idea I have is possibly using a mesh net with elastic which would allow for less moving pieces, points of error and trouble with design. Although I don’t know if I’ll be able to pull of my desired aesthetic as most OEM cupholders are designed using springs and hinges similar to the design sketches I have provided. There are a few occasions were they have been incorporated into production vehicles. Many offroad vehicles, from my experience, incorporate a similar mesh design but not for cups. It’s mainly used as the storage compartment on the door card or behind the passenger and driver seats. Going with a mesh design will also create some difficulty as there needs to be sufficient tension to hold the bottle in place and trying to incorporate this tension into a 3D printed part could cause trouble as the 3D print could snap if the design is not strong enough. Another issue lies with the mesh netting and cord, I have not used these materials to design anything in the past when I have more experience with springs and hinges. Although simple, this is not something I would like to underestimate.

Overall, I really like the plan I have laid out for this project. I still would like to try to include some more details. For starters, I would like to try and figure out a way to make the design look more like the aesthetic of OEM. I was thinking of possibly adding a Mazda logo to the print somewhere to achieve this. I’m also a little worried about the strength of the design. I don’t want this to be flimsy and end up breaking after a few uses and it’s really hard to tell if that’s the case from just the sketch and idea phase. Time will tell.