1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172 
Weighing up the anchors...
Page 58
Page 60
Page 61
If you've noticed an error in this article please click here to report it so we can fix it.
;ood brakes save lives. Not just lecause they help you stop in a lorry: the latest electronics can :ontrol your brakes so subtly that :hey can prevent a rollover. Sharon :lancy reviews the innovations.
The latest generation of disc brakes are designed to resolve some of the problems encountered on earlier systems, such as cracked iscs and leak problems.
Knorr-Bremse's SN disc brake supersedes the S B series; it is said to be about 3kg lighter thanks to a monobloc caliper assembly and fewer components. The caliper guide-pin bearings are fully sealed and the SN features a splined rather than a solid disc: Knorr-Bremse says this allows radial expansion, reducing the threat of cracking under thermal stress.
The brake is fitted as a single assembly by truck and trailer manufacturers, but when the time come to replace the disc the fitter simply breaks it into two pieces for easy removal and bolts the replacement in place. This is said to make the job faster, and thus cheaper. SB discs can be replaced by the SN equivalent luring routine servicing.
ArvinMeritor's LM and LMC railer axles, as well as the DX ;eries, can now be specified with ELSA II and DUCO 22.5111 air disc irakes (DUCO is a variant of ELSA). The idea is to offer matchng foundation brakes on tractors and trailers for MAN, Renault and Volvo operators—the ELSA brake s used by MAN and Renault, while Volvo uses the DUCO.
The ELSA air disc brake is a iliding-caliper design for 22.5in ,vheels. Its rated torque capacity S 28,000Nm with a swept disc irea of 2,o35cm2; the large 450cm2) pad area is designed for ow wear rates.
ArvinMeritor claims that )ecause ELSA 2 can take thicker iads than its competitors two sets of ELSA 2 pads will outlast three sets of pads in some other brakes. Pad wear adjustment is automatic; the brake can be supplied with electronic wear sensing or a simple visual indicator.
The ELSA 2 brake is a sealed, synchronized twintappet design with robust sealing of the slide pins to keep water out. The DUCO uses double seals in vulnerable areas, and critical components that could corrode in the event of a failed seal are made from stainless steel.
Both of these brakes rely on a simple. direct-acting lever actuating system that allows a weight saving of 2.51(g.
The manual adjuster used to wind off-the pads can withstand a torque of rooNm and an internal stop prevents the pistons from
disengaging from their threads, retaining their synchronisation. ArvinMeritor says resetting disengaged threads can take at least an hour, even with a specialist tool, adding that in some of its competitors' designs the complete brake has to be replaced.
Haldex's latest disc brake goes on sale later this year. It's a modu lar unit comprising an actuat mechanism, brake caliper a caliper bridge. The actuat mechanism has been redesigne it is now fully sealed in the facto and can be mounted in 1with the brake or radially to gi truck and trailer manufacture maximum flexibility..
Like the old brake, the no
odel has four stainless-steel ide pins as standard. Haldex elieves this offers better pro teeon against the guide-pin seizure ome operators have reported -th two-guide-pin set-ups.
Wabco's latest Perrot trailer isc brake, the PAN 19-I, is a ingle-piston unit. Compared ith the earlier version it is said save 14kg per axle on the 9.5in brake and 48kg per axle on the 2z.5in version. The guide shaft is encapsulated to protect against stone impact; KTL-cathodic painting enhances corrosion protection. Other advances include a reduced number of components to service and a patented pressure plate guidance system which minimises taper wear.