| 摘要 |
1,267,983. Multi-disc brakes; automatic operation fluid release; shaft couplings. NORTH AMERICAN ROCKWELL CORP. 18 July, 1969 [26 Sept., 1968], No. 36310/69. Headings F2E, F2F and F2U. A brake has co-operating engageable members respectively on a relatively-stationary support and a shaft connecting a selectively-energizable drive motor to a driven assembly; resilient biasing means acts on a plunger, defining with the support a fluid pressure chamber, in opposition to fluid pressure in the chamber; means are provided to introduce fluid into the chamber only upon energization of the drive motor to disengage the brake and consequently load the bias means; the loaded bias means are effective to displace the plunger to cause braking engagement upon reduction of fluid pressure consequent upon de-energization of the drive motor. In Fig. 4, when a valve 94 is opened to supply hydraulic fluid from reservoir 93 through pump 92 along line 95 to hydraulic motor 73 fluid also passes along line 97 to port 124 and passage 125 to force annular plunger 121 to the right, thereby releasing disc brake 133, 134 and compressing springs 129. Discs 134, which may be rectangular, are supported on pins 128 (e.g. four in number), while discs 133 are splined to a hollow coupling shaft 139 connecting the output shaft 72 of motor 73 with a shaft 142 having splined to it a shaft coupling 146. When valve 94 is closed, pressure in lines 95 and 97 is relieved, whereupon springs 129 immediately apply the brakes. A rigid spacer collar 147 is located between the inner end of shaft 139 and one side of a shoulder 148 on shaft 142. Bearing 143 is retained against the other side of shoulder 148 by spacer collar 149, bearing 144, coupling 146 and nut assembly 151. In Fig. 1, the plunger 59 and springs 88 are orientated the other way round; only three non- rotatable discs 83 are provided, and these are arcuately notched or apertured at 87 to accommodate pins 84 (e.g. six in number). Coupling shaft 71 is in this case externally splined at its inner end 74 to enter the splined hub 75 of a spur gear 15. The output shaft of speed reduction gearing 15, 32, 33, 41 is shown at 35. Fig. 3 (not shown) has the brake assembly and orientation of Fig. 4 with the shaft arrangements (to hub 75 of gear 15) of Fig. 1. The brake discs may have any peripheral configuration and may have frictional material or formations on one or both surfaces. Fewer discs than shown may be used in the Fig. 4 (or Fig. 3) embodiment, in which case housing portion 113 may be retained in the form shown, but an annular spacer of appropriate thickness is interposed between its inner face and the first stationary disc 134 (Figs. 6 and 7, not shown). |
