I. Overall Layout
1. Layout: Electric golf carts generally utilize an H-shaped, mild steel or aluminum alloy truss frame, lacking a complete body covering and representing a non-load-bearing structure. The power battery is located low below the seat, and the motor is rear-mounted, driving the rear axle or semi-independent suspension.
2. Wheelbase/Track: Two-seater vehicles have a wheelbase of 1.65–1.75 m, with a front track of approximately 1.05 m and a rear track of approximately 1.15 m. The wide track and low center of gravity ensure lateral stability at speeds of 14–16 km/h.
3. Ground Clearance: 110–120 mm unladen, 90–100 mm fully laden. The golf course must be smooth and level to ensure both passability and ease of entry and exit.
II. Materials and Lightweighting
1. Steel Frame: The mainstream design utilizes 50×50×3 mm rectangular tubing with 2 mm tread plates, electrophoretically treated for rust protection after welding. The entire chassis/body weighs 91–115 kg. While cost-effective, it is susceptible to rust in coastal areas.
2. Aluminum Alloy Frame (Club Car Exclusive): Aircraft-grade 6061-T6 trusses reduce weight by 25–30 kg, increase torsional rigidity by 8–10%, are corrosion-resistant, and have a lifespan of >20 years. However, raw material and welding costs are 25% higher.
3. Composite Materials: Some models utilize glass fiber-reinforced PP for the floorpan, reducing weight by 4–5 kg and reducing road noise by 2–3 dB.
III. Suspension System
1. Front Suspension
– A McPherson strut + anti-roll bar configuration is commonly used, with compact shock absorbers and coil springs integrated into the chassis. Front wheel turning angle is 52–55°, and the minimum turning circle is 2.9 m. – The lower control arm is constructed from a single-layer stamped steel plate or forged aluminum alloy, and the ball joint is replaceable separately. The rubber bushing has a static stiffness of 60–70 N/mm, ensuring both comfort and durability.
2. Rear Suspension
– Economy: Trailing arm + monotube shock absorber. Simple structure and no positioning required, but with noticeable steer bounce.
– Comfort: Torsion beam semi-independent. The crossmember is an open profile with a thickness of 4 mm. At a distance of 280 mm from the crossmember center to the wheel center, the roll stiffness is 0.55 kN·m/°, approximately 40% higher than a trailing arm.
– High-End/Off-Road: True independent, with double A-arms and coil springs. Each wheel has a travel of 120 mm and a track variation of less than 8 mm. It is suitable for climbing a 25° grade and a 50 mm gravel road. 3. Tuning Features
– No-load offset frequency: 1.4 Hz front, 1.6 Hz rear; fully loaded, the frequency variation is ≤ 0.15 Hz, ensuring ride consistency under varying loads.
– The shock absorber speed-damping curve uses a broken-line design, with 300 N at low speeds of 0.1 m/s and 650 N at medium speeds of 0.3 m/s, effectively suppressing bouncing over speed bumps on the court.
IV. Steering and Braking
1. Steering: Rack-and-pinion, 14:1 gear ratio, 3.2 steering wheel turns; the electric power steering version provides 3 N·m of assist below 6 km/h, reducing stationary steering effort by 35%. 2. Braking: Rear hub-mounted mechanical brake combined with electric motor regenerative braking, with a braking distance of ≤ 2.5 m at 20 km/h under full load. The mechanical component utilizes a Ø180 mm cast iron drum, and the brake pads are 15% wider than those on similar-sized passenger cars to improve corrosion resistance and lifespan.
V. Battery-Motor-Frame Integration
1. Battery Frame: Lead-acid 6×8 V or 8×6 V combination, weighing 140–160 kg, flexibly connected to the frame via four-point rubber pads to isolate 20–30 Hz road excitation.
2. Lithium Battery Upgrade: LiFePO₄ packs, 2.5–3.0 kWh, reducing mass by 45%. Local frame reinforcement beams reduce weight by 1.5 kg, increasing driving range by 15–20 km. 3. Rear-mounted motor: Peak power 3.5–5.0 kW, directly bolted to the rear axle housing via flange, eliminating universal joints, shortening the drive train by 120 mm and improving efficiency by 2–3%.
VI. Strength and Fatigue Verification
1. Bending Condition: Fully loaded with 830 kg (including passengers), the frame experiences a maximum vertical deformation of 1.16 mm at the bend of the front crossmember. The bending stiffness is 1,050 N/mm, meeting the design target of <1.5 mm.
2. Torsion Condition: 200 mm boss per wheel, frame torsion angle 0.9°, corresponding to a torsional stiffness of 1,250 N·m/°, ensuring balanced four-wheel contact and suspension travel. 3. Fatigue Safety Factor: For Q345 welded joints, the calculation is 2.5 times the dynamic load factor × 1.2 times the fatigue factor. Maximum stress 210 MPa < parent material 280 MPa, resulting in a safety margin of 1.33.
VII. A Quick Look at Chassis Differences Between Mainstream Brands
Specifications: Club Car Onward E-Z-GO RXV Yamaha Drive2
Frame Material: Aluminum Alloy Truss, Steel Rectangular Tube, Steel Rectangular Tube
Front Suspension: McPherson + Stabilizer Bar, McPherson, Independent Double A-Arm
Rear Suspension: Torsion Beam, Trailing Arm, Torsion Beam
Minimum Ground Clearance: 114 mm, 110 mm, 115 mm
Brakes: Rear Drum + Regenerative, Rear Drum + Regenerative, Rear Drum + Regenerative
Warranty: 5 Years, Frame Corrosion Protection: 3 Years, 3 Years
Notes: Best corrosion resistance, highest price. Cheap parts, prone to rust. Self-developed motor, good climbing.
VIII. Summary
– The golf cart chassis focuses on “lightweight, corrosion resistance, and low cost,” with suspension tuning optimized for low-speed comfort.
– The combination of an aluminum alloy frame and a lithium battery is the primary direction for future weight reduction and vehicle life extension.
– The torsion beam semi-independent rear suspension strikes a balance between comfort and cost, while the independent rear suspension is designed for off-road and multi-purpose use.
– CAE stiffness verification and bench fatigue testing guarantee a service life of over 10 years, meeting the demands of both the golf course and community roads.