For years, Subaru suspension designs have had a little bit more body roll than its competition. It's caused by longer travel and softer springs, and it helped give the brand the soft ride with excellent performance on gravel that built its reputation. But on pavement, those wayward motions aren't always ideal.SubaruNow Subaru engineers have come up with a way to shift the roll axis of the vehicle, reducing body roll without ruining that ride. CarBuzz recently found a patent that, quite literally, screws up the suspension. Move The Pivot Points, Move The World SubaruA stabilizer bar, or anti-roll bar, is a metal rod that is connected to the vehicle's suspension at the left and right sides of the same axle. When you turn, the car's body rolls toward the outside, compressing the suspension on that side while rebounding or expanding on the inside. This movement twists the anti-roll bar, which stops the suspension from moving further.It works amazingly well to stop body roll, with a stiff enough bar all but eliminating it. Go too far, though, and every bump will send a jolt through the cabin. It also reduces articulation, where one wheel can move up and down independently of the one opposite, a feature that is crucial off pavement.Every anti-roll bar is mounted to the chassis through bushings that are spaced symmetrically an equal distance from the center line. That way, the bar acts the same way in both roll directions. Subaru's idea would change that completely. Engineers have come up with a mounting bushing with a screw thread along with a motor. Using the motor to drive the screw, it can move the bar's mounting points as you drive, basically changing the lever on both sides at the same time. Makes Sports Cars More Responsive, Makes SUVs Feel 'Excessive' Chaydon Ford/Subaru Motorsports USATurn right, and the mounting points shift to the right. This makes the lever arm shorter on the right side of the car, which increases the force of the bar on that wheel and reduces suspension travel while decreasing the force on the left side. It moves the roll center toward the inside of the corner. All that to say that the sway bar shifts as you turn, and that, as Subaru says in the patent, "enables yawing to be quickly generated, and high response performance to be obtained. Hence, this control is suitable for a sports vehicle or the like."It also works for cars that aren't sporty, to slow them down. Subaru says moving the roll center in the opposite direction, so to the outside, increases understeer. That's an odd choice, but Subaru says "as a result, the driver can feel that the vehicle speed is excessive." It says that's suitable for tall SUVs and vans, which corner at slower speeds than sports cars.Adding screws and motors under your vehicle isn't going to immediately win fans. Putting delicate mechanisms where they'll be pelted by dirt, rocks, rain, and salt, is a recipe for problems. But if Subaru can seal everything properly, then this idea has a lot of promise. Plus, with a smaller bar able to limit movement like a large one, straight-line ride comfort should also be improved.We're not sure why you'd want to make SUV drivers feel like they're going faster than they are. But we are sure why you'd want a sports car – like the BRZ or WRX – to be more agile and more responsive.Patent filings do not guarantee the use of such technology in future vehicles and are often used exclusively as a means of protecting intellectual property. Such a filing cannot be construed as confirmation of production intent.Source: US Patent & Trademark Office
+34 others
