V-BELT PULLEY

Abstract: V-belt pulley comprising an outer rim (2) provided with at least one V-belt groove (7) formed by turning, said groove (7) having a bottom (9) provided with a plurality of radially through-going and circumferentially interspaced openings (8). The pulley is cast with a rim (2) having a radially inwardly facing surface (4) is provided with a plurality of circumferentially interspaced recesses (5) of such a radial depth that the radially through-going openings are formed by the turning thereof.

Description: Title: V-belt pullev Technical Field The invention relates to a V-belt pulley comprising an outer rim provided with at least one outwardly facing V-belt groove formed by turning in whose bottom a plurality of radially through-going openings are circumferentially interspaced and extend to the radially inwardly facing surface of the rim. Background Art Such a V-belt pulley is known from GB patent nr. 865 797, in which the radial openings are formed by radial cutting through the rim of the V-belt pulley. Brief Description of the Invention The object of the invention is to provide a V-belt pulley of the above type which can be made in a simple and rational manner. The V-belt pulley according to the invention is characterised in that the pulley is cast with a rim having a radially inwardly facing surface provided with a plurality of circumferentially interspaced recesses of such a radial depth that the bottom thereof is arranged radially outside of the bottom of the V-belt groove such that the radially through-going openings are made by the turning thereof. By forming the V-belt pulley with said recesses in its rim, the openings are automatically produced by turning of the V-belt groove. The cutting process of the V-belt pulley may thus be carried out in a manner corresponding to a conventional V-belt pulley without radial openings, whereby separate machining thereof is avoided. Consequently V-belt pulleys with openings which act to cool the pulley and V-belt and thus prolongs the life of the latter can be made essentially without increased production costs. Tests have shown that by using the V-belt pulley according to the invention the belt temperature is decreased by 10-15°C in relation to the use of conventional V-belt pulleys without radial openings in the bottom of the groove. According to the invention, when seen in axial direction the radial recesses may have a groove-like form and thus be cast without using separate cores. Furthermore according to the invention the recesses may be axially through-going from one side of the pulley to the other. Moreover according to the invention the openings may be substantially evenly inter- spaced when seen in circumferential direction. According to the invention, the radial openings may be of a length substantially corresponding to their interspacing when seen in circumferential direction. Furthermore according to the invention the length of the openings may be 7-30 mm, preferably 15-25 mm when seen in circumferential direction. Moreover according to the invention the depth of the recesses is such that the radial outer portion of the openings made by the turning of the groove is arranged radially inside of the V-belt received in the groove, whereby the V-belt does not engage the portion of the V-belt groove, in which the openings are formed. Finally according to the invention the V-belt pulley may be made of SG iron. Brief Description of the Drawings The invention is explained in greater detail below with reference to the accompanying drawing, in which Fig. 1 is a side view of the V-belt pulley according to the invention and Fig. 2 illustrates the V-belt pulley in Fig. 1 along the line II-II in Fig. 1. Best Mode for Carrying Out the Invention The drawing illustrates a cast V-belt pulley according to the invention comprising a hub 1 connected to a rim 2 by means of three spokes 3. During casting a plurality of recesses 5 is formed in the radially inwardly facing surface 4 of the rim, said recesses 5 being circumferentially evenly interspaced between the spokes 3. In axial direction the recesses 5 have a groove-like form and extend from one side of the rim to the other. Four V-belt grooves 7 are formed in the outer surface of the rim by turning. The depth of the grooves 7 and the recesses 5 is such that openings 8 are formed between the bottom 9 of the grooves adjacent recesses when the grooves are turned. In other words, the bottom 13 of the recesses is arranged radially outside of the bottom 9 of the grooves 7. For illustration hereof the bottom 9 of the grooves 7 is shown as a dotted line in Fig. 1 and in the enlarged section thereof - even though it is not visible in these Figures. As it appears from the far right groove in Fig. 2, the depth of the recesses 5 is further such that the radially outer portion 10 of the openings formed by turning of the grooves is arranged radially inwardly of a V-belt 11 (shown dotted) received in the groove, whereby the V-belt is prevented from coming into contact with the openings and thus from being damaged. The hub is provided with an axial conical bore for mounting the V-belt pulley on a shaft. As mentioned above the V-belt pulley is made by cutting of a cast workpiece. The cast workpiece may be formed by any casting process, ie by using a non-permanent ( expendable) mould or a permanent mould. Furthermore the cast workpiece may be of any metal or iron alloy. However, preferably the cast workpiece is made of SG iron by sand casting. Preferably, the only surfaces of the V-belt pulley which are processed by machining are: The outer peripheral face 6 of the groove 7, the lateral faces 14, 15 and the bore 12 and the lateral faces 16,17 of the hub 1. As a result of the obtained cooling action, the V-belt pulley according to the invention is particularly advantageous in connection with the various types of narrow V-belts, ie type SPA, SPZ, SPB and SPC, but can of course be adapted to other types of V-belts.

Claims: Claims 1. V-belt pulley comprising an outer rim (2) provided with at least one outwardly facing V-belt groove (7) formed by turning, said groove (7) having a bottom (9) provided with apluraUty of radially through-going and circumferentially interspaced openings (8) extending to the inwardly facing surface (4) of the rim, characterised in that the pulley is cast with a rim having an inwardly facing surface (4) provided with a plurality of radial recesses (5) circumferentially interspaced and of such a depth that the bottom thereof is radially beyond the bottom of the V-belt groove (7) such that the radially through-going openings (8) are formed by the turning thereof. 2. V-belt pulley according to claim 1, characterised in that the radial recesses (5) have a groove-like form when seen in axial direction. 3. V-belt pulley according claim 1 or 2, characterised in that the recesses are axially through-going from one side of the pulley to the other. 4. V-belt pulley according to one or more of the preceding claims, characterised in that the openings (8) are substantially evenly interspaced when seen in circumferential direction. 5. V-belt pulley according to one or more of the preceding claims, characterised in that the radial openings (8) are of a length substantially corresponding to their interspacing when seen in circumferential direction. 6. V-belt pulley according to one or more of the preceding claims, characterised in that the length of the openings is 7-30, preferably 15-25 mm when seen in circumferential direction. 7. V-belt pulley according to one or more of the preceding claims, characterised in that the depth of the recesses (5) is such that the radially outer portion (10) of the openings (8) formed by turning of the groove (7) is arranged radially inside of a V-belt received in the groove (7). 8. V-belt pulley according to one or more of the preceding claims, characterised in that it is made of SG iron.

Inventors: BIRN VALDEMAR, BIRN, VALDEMAR
Applicants: BIRN VALDEMAR, VALD BIRNS MASKINFABRIK A S, BIRN, VALDEMAR, VALD.BIRNS MASKINFABRIK A/S
Application year: 1998
Main classification: F16H55
IPC codes: F16H55