Uber's board of directors on Tuesday approved reforms that limit the power of Travis Kalanick, the ride-hailing company's co-founder and former CEO.

The board voted to eliminate its super-voting structure, in which early shareholders had 10 times the voting power, to a one vote per share model, according to a source familiar with the vote. The board also voted to expand the number of board members to 17, adding six seats to dilute recent additions made by Kalanick.

The vote came after Kalanick, who resigned in June but remains on the company's board, appointed two new members on Friday, a move other directors described as "a complete surprise." The board approved the sale of $10 billion of stock to Japanese internet giant SoftBank.

"Today, after welcoming its new directors Ursula Burns and John Thain, the Board voted unanimously to move forward with the proposed investment by SoftBank and with governance changes that would strengthen its independence and ensure equality among all shareholders," the board said in a statement about the vote. "SoftBank's interest is an incredible vote of confidence in Uber's business and long-term potential, and we look forward to finalizing the investment in the coming weeks."

The board also approved a proposal that requires two-thirds of the board to approve any new CEO appointments. Kalanick, who was forced out by investor pressure, was said to be trying to engineer a plan to return as the company's CEO. 

The vote comes amid a tumultuous year for the ride-hailing startup, which has been rocked by a slew of scandals, including sexual harassment allegations that resulted in more than 20 Uber employees being fired. The company has been caught using a secretive tool called Greyball to avoid local authorities. The company is also defending itself against a trade-secret theft lawsuit from Waymo, a self-driving car business run by Alphabet, Google's parent company.

Kalanick is also currently facing a lawsuit from one of Uber's early investors that alleges he misled stockholders to gain control of three board seats. Kalanick has responded by calling the lawsuit a "public and personal attack."

Solving for XX: The industry seeks to overcome outdated ideas about "women in tech."

Special Reports: All of CNET's most in-depth features in one easy spot.

More to come.