NTN Develops High Performance Ball Type Sliding CVJ for EVs
May 13, 2025
- Improving sliding type CVJ “EDJ” with the world's best level in compactness and excellent responsiveness
- High performance model for EVs that improves quietness and efficiency by adopting the newly developed grease
NTN Corporation (hereafter, NTN) has improved the Ball Type Sliding CVJ (constant velocity joint) “EDJ*1” with the world's best level in compactness (small size and lightweight) and excellent responsiveness to develop the high performance model that improves quietness and efficiency for EVs (electric vehicles).
By adopting the newly developed grease, the developed product meets EV's specific needs such as compactness, responsiveness, and quietness. NTN will add the developed product to our product lineup of driveshafts for EVs and propose it globally.
- Abbreviation of E series Double offset Joint. The E series is one of our CVJ series featuring compactness and lightweight.
Ball Type Sliding CVJ “EDJ”
Background of development
In order to improve electricity efficiency towards extending EV's cruising distances, driveshafts for EVs are required to reduce torque loss ratio (improve efficiency) and transmit torque from motors to tires without torque loss. In EVs, the powertrain unit is changed from an engine to a motor, which reduces the noise and vibration generated by the vehicle. Due to the change, driveshafts for EVs are also required to improve quietness. Furthermore, there are growing needs for compactness to provide a large interior and cargo space, and high responsiveness to achieve direct driving performance by taking advantage of the motor's excellent response.
NTN has been providing “EDJ” as a sliding type CVJ with compactness and excellent responsiveness. To meet EV's specific needs, we have developed the high performance model for EVs that improved quietness and efficiency while maintaining compatibility with the conventional “EDJ” by combining the newly developed grease with “EDJ.”
Features
| 1. Quietness and low vibration | We analyzed the mechanism of the vibration during driving and identified that it is caused by minute variations in contact conditions between each ball and inner/outer race. We have improved quietness and vibration during driving by uniformizing contact conditions and adopting the newly developed grease to reduce friction. |
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| 2. High efficiency | Reviewing composition of grease additives reduces friction between parts. By suppressing heat generation during transmitting torque, the developed product reduces torque loss ratio by 25% compared to the conventional product. |
| 3. Compactness and responsiveness | The developed product maintains the features of the conventional product of the world's best level in compactness as ball type sliding CVJs and excellent responsiveness. As its circumferential backlash between internal parts is small, it can transmit torque smoothly. |
NTN offers “EDJ” with compactness and responsiveness, and “PTJ*2” with excellent efficiency and shudderless as sliding type CVJs. We will combine each CVJ with our fixed type CVJ “CFJ*3” which has the world's best level in transmission efficiency and globally propose them as the optimum driveshafts for EVs*4 that meet various needs of EVs.
NTN will exhibit the developed high performance model of “EDJ” at the “Automotive Engineering Exposition 2025 YOKOHAMA” to be held from May 21 to 23 at PACIFICO Yokohama in Japan.
- Abbreviation of Pillow journal Tripod Joint.
- Abbreviation of Cross groove Fixed Joint.
- Press release on May 23, 2024:
NTN Starts Proposal of High Efficiency/Shudderless Driveshaft for EVs
https://www.ntnglobal.com/en/news/new_products/news202400045.html
Structure of “EDJ”
A sliding type CVJ that uses balls for sliding motion
Small clearance between the ball and internal components
provides excellent responsiveness and low vibration during startup and acceleration
About driveshaft
Driveshaft is a component of automobiles that transmits power (torque) of powertrain unit such as an engine and a motor to tires. NTN was the first company in Japan to successfully mass produce driveshafts in the 1960s and continues to have one of the top market shares in the world today.
A driveshaft consists of two constant velocity joints (CVJs) and a shaft connecting them.
Generally, the sliding type CVJ used on the powertrain side can slide in the axial direction but has a small operating angle, while the fixed type CVJ on the tire side cannot slide but has a large operating angle.
Driveshaft for EVs that adopts the “CFJ” that
features excellent efficiency as a fixed type CVJ and the “EDJ” as a sliding type CVJ
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