{"id":4601,"date":"2019-11-25T09:30:35","date_gmt":"2019-11-25T07:30:35","guid":{"rendered":"https:\/\/blog.febi.com\/?p=4601"},"modified":"2019-11-25T10:38:45","modified_gmt":"2019-11-25T08:38:45","slug":"abs-sensors-preventing-commercial-vehicle-brakes-from-jamming","status":"publish","type":"post","link":"https:\/\/blog.febi.com\/en\/abs-sensors-preventing-commercial-vehicle-brakes-from-jamming\/","title":{"rendered":"ABS Sensors: Preventing Commercial Vehicle Brakes from Jamming"},"content":{"rendered":"\n

ABS, ESP, ASR: Nowadays, commercial vehicles are packed with driver assistance systems. For these to function, they require data from a wide variety of sensors in the vehicle. An example of such data includes the precise wheel speed of all braked wheels. This collection of data is the only way the control units can perform their calculations precisely in a fraction of a second.<\/p>\n\n\n\n

If a wheel speed sensor\nfails, a malfunction is signaled to the driver and the systems no longer\noperate the way they were designed to. ABS, EBS, and many other systems are\nthen rendered inactive. This can lead to wheel lock-up or the appearance of\nfalse alarms. In addition, the ABS indicator lights up and a fault is stored in\nthe control unit. “A defect in the ABS system should be repaired\nimmediately since driving safety is impaired as a result,” explains Sascha\nKeller, Technical Marketing Manager Truck at Ferdinand Bilstein. Under its febi\nbrand, the company offers a large number of components<\/a>\nfor the ABS system.<\/p>\n\n\n\n

Passive sensors are widely used in commercial vehicles<\/p>

<\/p>– Sascha Keller, Technical Marketing Manager Truck <\/cite><\/blockquote>\n\n\n\n

ABS Ring<\/strong><\/h2>\n\n\n\n

The ABS ring and the ABS\nsensor \u2013 also known as the speed sensor \u2013 are responsible for the generation of\nsignals. There is a distinction between active and passive sensors. “In\nthe commercial vehicle sector, passive sensors are used to a great extent;\nactive sensors play only a subordinate role,” says Keller.<\/p>\n\n\n\n

The sensor ring is available\nin a variety of designs: as a sheet metal piece or made of solid material (Fig.\n1). In many cases, the shaft seal is integrated to the seal of the wheel hub or\nthe sensor ring is included in the casting of the brake disc. As a rule,\ncommercial vehicle sensor rings have 100 teeth. <\/p>\n\n\n\n

ABS Sensor<\/strong><\/h2>\n\n\n\n

The ABS sensor is mounted\ndirectly in front of the sensor ring. The ABS ring is connected to a rotating\npart \u2013 such as the brake disc or the wheel hub (Fig. 2). Inside the sensor, there is a pole pin surrounded\nby a coil in contact with a permanent magnet. The magnetic field of this structure reaches to\nthe sensor ring and detects through the fluctuation of the magnetic field if a\ntooth or a tooth gap of the sensor ring is in the magnetic field. If the magnetic field changes, a low\nalternating voltage is generated in the coil whose frequency and amplitudes\nserve as a speed signal for the control units. In contrast to the active\nsensors, the passive sensors do not require their own power supply from the\ncontrol unit.<\/p>\n\n\n\n

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Fig. 1<\/figcaption><\/figure>\n\n\n\n

Repair of a Faulty ABS Sensor<\/strong><\/h2>\n\n\n\n

Reasons for ABS Sensor Failure<\/strong><\/p>\n\n\n\n

A failure of the ABS sensor can\nbe caused by various factors \u2013 for example:<\/p>\n\n\n\n