{"id":166,"date":"2020-04-24T14:00:00","date_gmt":"2020-04-24T06:00:00","guid":{"rendered":"https:\/\/www.juemeis.xyz\/wordpress\/?p=166"},"modified":"2020-04-24T14:00:00","modified_gmt":"2020-04-24T06:00:00","slug":"%e3%80%90%e8%bd%a6%e5%90%8e%e3%80%91%e5%88%b9%e8%bd%a6%e7%9b%98%e7%9a%84dtv%e4%b8%8ebtv%e6%98%af%e4%bb%80%e4%b9%88%ef%bc%9f","status":"publish","type":"post","link":"https:\/\/www.urbin.top\/?p=166","title":{"rendered":"\u3010\u8f66\u540e\u3011\u5239\u8f66\u76d8\u7684DTV\u4e0eBTV\u662f\u4ec0\u4e48\uff1f"},"content":{"rendered":"\n

\u8f6c\u8f7d\u81ea\u7f51\u8def\u5e76\u6574\u7406<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

The\ndifference between DTV pulsation and BTV \njudder<\/p>\n\n\n\n

New brake\nrotors and pads do not solve pulsation, judder or premature wear problems; they\nonly mask the root cause for a short period of time. The only problem new pads\nand rotors can solve is the elimination of parts that are below specifications.<\/p>\n\n\n\n

Looking at\nthe big picture of the measurements, vehicle and driver together is the only\nway to solve a customer complaint when it comes to brakes. Having knowledge of\nwhat happening between rotor, pad and caliper is also important.<\/p>\n\n\n\n

Pulsation = DTV<\/strong> <\/p>\n\n\n\n

The main\nculprit of pulsation problem is variation in the disc thickness or parallelism.\nThe two surface of a rotor are designed to be parallel to one set of\nspecification.<\/p>\n\n\n\n

The\nallowable tolerance is known as parallelism. It is also known as the rotor’s\ndisc thickness variation or DTV. In order for pad to stay in contact with the\nrotor, the piston must extend or be pushed back into the housing as force is\napplied. This creates the pulsation in the pedal that is most noticeable to the\ndriver in how the pedal feels.<\/p>\n\n\n\n

Every time\nthe low spot passes by the caliper, hydraulic pressure the caliper drops. This\nproduces less braking force as this passes by the pads. This can also affect\nbraking distances.<\/p>\n\n\n\n

Lateral\nbrake runout means the rotor wobbles from side to side when spinning. Think of\nit as the rotor or flange moving in a plane that is not the same as that of the\npads or caliper. Lateral runout will cause the rotor to contact the brake pads,\nknocking them back as the high spot of the runout contact the pads. This allows\nmore pedal travel before the pad’s surface makes contact with the rotor.<\/p>\n\n\n\n

Judder = BTV<\/strong><\/p>\n\n\n\n

Judder is\na vibration that can be felt in the seat or steering wheel, but it will not\ncause pulsing of the pedal in most cases. Judder can occur in a vehicle with\nzero runout or DTV, and is caused by brake torque variation(BTV). BTV occurs\nwhen there is a variation of torque across the face of the rotor that causes\nthe rotor to slip and catch as brake pads pinch the rotor. BTV may be caused by\nan inconsistent rotor finish, metallurgy or uneven deposits of friction\nmaterial on the face of the rotor.<\/p>\n\n\n\n

Judder is\na vibration that can be felt in the seat or steering wheel, but it will not\ncause pulsing of the brake pedal in most cases. Judder can occur in vehicle\nwith zero runout or DTV, and is caused by brake torque variation (BTV). BTV\noccurs when there is a variation of torque across the face of the rotor that\ncauses the rotor to slip and catch as brake pads pinch the rotor. BTV may be\ncaused by an inconsistent rotor finish, metallurgy or uneven deposits of\nfriction material on the face of rotor.<\/p>\n\n\n\n

Knowing\nthe difference between pulsation (DTV) and judder (BTV) is critical to solving\nany brake complaint and avoiding a problem in the first place. Assuming that\nnew pads and rotors will automatically fix the problem will only create more\nissues with the customer when the vehicle inevitably comes back.<\/p>\n\n\n\n

Knowing\nthe difference between pulsation (DTV) and judder (BTV) is critical to solving\nany brake complaint and avoiding a problem in the first place. Assuming that\nnew pads and rotors will automatically fix the problem will only create more\nissues with the customer when the vehicle inevitably comes back.<\/p>\n\n\n\n

Rotor\nfinish and transfer layers<\/p>\n\n\n\n

The\nfriction between the two surfaces change forward motion into heat. But, there\nis a lot of science that goes into what happens at the molecular level to\nchange braking force into heat.<\/p>\n\n\n\n

Most\nsemi-metallic brake pads use the two different surface materials of the pad and\nrotor to make friction. The abrasive action wears away the two surfaces.<\/p>\n\n\n\n

Ceramic\nand some NAO pads transfer a thin layer of pad material onto the surface of the\nrotor. The transfer layer is bonded to the rotor’s surface and cannot be washed\naway by water or wheel cleaners. The only way to remove it is by using a brake\nlathe or abnormal heat. With this type of pad, it is critical to machine the\nrotor with the correct surface finish and follow the recommended break-in\nprocedure so the transfer layer can be established.<\/p>\n\n\n\n

Adherent\nfriction is easier on rotors, but the pads become the primary wear component.\nThe layer is always worn and replenished by the brake pad during braking, so\nthese pads produce dust. The smoothness of the friction surface of a rotor is\ndescribed in term of micro finish or RA factor. RA stands for “roughness\naverage” and represents a way to measure the smoothness of a rotor. Most\nlathes on the market will yield very acceptable RA factors when they are in\ngood condition and are used properly. The finish is essential to transfer\nmaterial for organic and ceramic friction materials. The correct finish is also\nessential for semi-metallic pads so they can have the correct coefficient of\nfriction during initial break-in.<\/p>\n","protected":false},"excerpt":{"rendered":"

\u8f6c\u8f7d\u81ea\u7f51\u8def\u5e76\u6574\u7406 The difference between DTV pulsation and […]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[11,13,26,47,48],"class_list":["post-166","post","type-post","status-publish","format-standard","hentry","category-am","tag-btv","tag-dtv","tag-26","tag-47","tag-48"],"_links":{"self":[{"href":"https:\/\/www.urbin.top\/index.php?rest_route=\/wp\/v2\/posts\/166","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.urbin.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.urbin.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.urbin.top\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.urbin.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=166"}],"version-history":[{"count":0,"href":"https:\/\/www.urbin.top\/index.php?rest_route=\/wp\/v2\/posts\/166\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.urbin.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=166"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.urbin.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=166"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.urbin.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=166"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}