V-BELT TRANSMISSIONS

Abstract: A V-belt transmission is disclosed in which an endless metallic belt (7) is provided with a large number of V-shaped metallic members (8,8, ....), each having an engaging surface (10) facing the metallic belt. The metallic members are dis­ posed in an array along the lengthwise direction of the end­ less metallic belt so as to make, as a whole, a V-belt assembly. This V-belt assembly is applied between a driving V-pulley (2) and a driven V-pulley (4) so as to effect power transmission therebetween. A large number of intermediate members (9,9,....) are so interposed between respective adjacent metallic members (8,8,....) and positioned inside the metallic belt (7) as to be fastened together from the outer periphery thereof with the metallic belt. The transmission is character­ ised in that each ofthe V-shaped metallic members (8, 8,....) is so held between a corresponding two of the intermediate members (9, 9,....) which are located on mutually opposite sides of the metallic member (8) in the lengthwise direction of the metallic belt (7) as to be moveable inwards and outwards so that when the respective V-shaped metallic members (8, 8,....) are brought into engagement with eitherofthe V-pulleys (2, 4), the metallic members (8, 8,....) are pushed by the V-pulley (2 or 4) to be moved outwards to be brought into pressure contact connection, at their engaging surfaces (10), with the metallic belt (7). By arranging in the present V-belt assembly that when respective V-shaped metallic members are brought into engagement with respective V-pulleys, the metallic members are forced to move outwards to be brought into pressure contact connection with the inner circumferen­ tial surface of the metallic belt, the connection of the metallic members with thee metallic belt can he increased in compari­ son with a V-belt assembly in which the V-shaped metallic members are connected only through the intermediate mem­ bers to the metallic belt.

Description: V-BELT TRANSMISSIONS This invention relates to V-belt transmissions usable in stepless variable speed transmissions in vehicles. The invention is particularly concerned with a V-belt transmission in which an endless metallic belt is provided with a large number of V-shaped metallic members, each having an engaging surface facing the metallic belt, the metallic members being disposed in an array in the lengthwise direction of the endless metallic belt so as to make, as a whole, a V-belt assembly, and this V-belt assembly is applied between a driving V-pulley and a driven pulley for effecting power transmission therebetween. For such a V-belt assembly it has been proposed that intermediate members such as hollow rollers are so interposed between respective adjacent metallic members and positioned inside the endless metallic belt as as to be fastened together from the outer periphery with the metallic belt, and by this fastening, the respective metallic members are connected to the metallic belt through the respective intermediate members. In this case, in order that a tension force caused by turning of the driving V-pulley may act on the metallic belt and make an effective power transmission, it is desirable further to l rease the connections between tile respective metallic members and the metallic belt in a turning region of the belt at the V-pulley. According to the present invention there is provided a V-belt transmission in which an endless metallic belt is provided with a large number of V-shaped metallic members, each having an engaging surface facing the metallic belt, the metallic members being disposed in an array along the lengthwise direction of the endless metallic belt so as to make, as a whole, a V-belt assembly, this V-belt assembly being applied between a driving V-pulley and a driven V-pulley so as to effect power transmission therebetween; and a large number of intermediate members so interposed between respective adjacent metallic members and positioned inside the metallic belt as to be fastened together from the outer periphery thereof with the metallic belt; characterised in that each of the V-shaped metallic members is so held between a corresponding two of the intermediate members which are located on mutually opposite sides of the metallic member in the lengthwise direction of the metallic belt as to be movable inwards and outwards so that when the respective V-shaped metallic members are brought into engagement with either of the V-pulleys the metallic members are pushed by the V-pulley to be moved outwards to be brought into pressure contact connection, at their engaging surfaces, with the metallic belt. By arranging that when respective V-shaped metallic members are brought into engagement with respective V-pulleys, the metallic members are forced to move outwards to be brought into pressure contact connection with the inner circumferential surface of the metallic belt, the connection of the metallic members with the metallic belt can be increased in comparison with a V-belt assembly in which the V-shaped metallic members are connected only through the intermediate members to the metallic belt. For a better understanc#ng of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which: Figure 1 is a side view, partly in section, of a variable-speed power transmission; Figure 2 is an enlarged sectional side view of a portion of the transmission of Figure 1; Figures 3 to 5 are sectional views taken, respectively, along lines III-III, IV-IV and V-V in Figure 2; Figure 6 is a sectional side view on a larger scale of a V-shaped metallic member of a V-belt of the transmission of Figures 1 to 5; Figure 7 is a sectional side view similar to Figure 6 but of a modified metallic member, and Figures 8 to 11 are sectional views similar to Figure 4 but of modified form. Referring first to Figures 1 to 6 numeral 1 denotes the variable speed transmission, which is for a motorised two-wheeled vehicle. In the transmission 1 a V-belt assembly 6 is applied between a V-groove 3 of a variable driving V-pulley 2 and a V-groove 5 of a variable driven V-pulley 4 for effecting power transmission between the twc pulleys 2, 4. In the V-belt assembly 6 an endless metallic belt 7, which comprises plural belt members 7a, 7a, .... of hoop configuration put one upon another in layers, is provided with a large nuller of Vshaped metallic members 8, 8, ...., each having both lateral inclined surfaces 8a, 8a disposed to be brought into contact with the inner surface of each of the V-grooves 3, 5, the metallic members 8, 8, .... being disposed in an array in the lengthwise direction of the metallic belt 7. Intermediate members 5, 5, .... are so interposed betweer respective adjacent metallic members 8, 8, .... and positioned inside the metallic belt 7 as to be fastened together from the outer periphery thereof with the metallic belt 7, and, by this fastening, the respective metallic members 8, 8, .... are connected to the metallic belt 7 through the respective intermediate members 9, 9, ..... In the illustrated example, each of the metallic members 8, 8, ... is provided with a groove 11 which is open outwards and has at its bottom portion an engaging surfae 10 facing the metallic belt 7, and each of the metallic members 8, 8, .. is mounted at its groove 11 on the metallic belt 7 from inside. For each member 8, a retainer 13 facing the outer circumferential surface of the metallic belt 7 is mounted in the groove 11 in egagement with engaging grooves 12, 12 made in upper portions of side wall portions Ila, Ila defining both sides of the groove 11, so that the respective metallic members 8, 8, are areprevented by the respective retainers 13, 13, .... from coming off inwards from the belt 7. Each of the metallic members 8, 8, ....is so held between a corresponding pair of the intermediate members 9, 9 located on mutually opposite sides of the meeber 8 in the lengthwise direction of the metallic belt 7 as to be movable inwards and outwards, so that when each of the metallic members 8, 8, .... is brought into engagement with each of the V-pulleys 2, 4, the member 8 is pushed by the V-groove of the corresponding V-pulley to slide outwards to be brought into pressure contact connection, at the engaging surface 10, with a lower surface of the metallic belt 7. Consequently, when the respective metallic members 8, 8, ....are brought into engagement with the driving V-pulley 2 and accordingly are turned by the turning of this V-pulley 2, the metallic belt 7 can be given a tension driving force in accordance therewith. In more detail, each of the metallic members 8, 8, .... is in engagement with a corresponding pair of the intermediate members 9, 9 at its recessed receiving surfaces 14, 14 that are in mutually opposite surfaces located in the lengthwise direction of the metallic belt 7. In this case each of the recessed receiving surfaces 14, 14 is not shaped to conform to a shape of each of the intermediate members 9, 9 but is, instead, shaped such that it has a linear plane 14a extending in inner and outer directions, as shown in Figure 6 or 7, so that each of the metallic members 8, 8, .... may be allowed to move inwards and outwards within the range of this linear plane 14a. Thus, at a linear movement region of the V-belt assembly 6, as shown in Figure 3, there exists more or less of a gap between the metallic belt 7 and the engaging surface 10 facing thereto, but at a turning movement region of the assembly 6, in which it is engaged with one or other of the V-pulleys 2, 4 as shown in Figure 4, each of the metallic members 8, 8, .... is pushed by the pulley to move outwards, the metallic belt 7 and the engaging surface 10 are in pressure contact with one another, and there is established such a condition that the metallic belt 7 and each of the metallic members 8, 8, .... are firmly connected together. In order to make smooth relative inclining motions of the respective V-shaped metallic members 8, 8, .... at the turning movement region, each of the intermediate members 9, 9, .... ia preferably so formed that at least a contact surface thereof which is in contact with each receiving surface 14 is in the form of an arc in section. Additionally, it is preferable that some or all of the intermediate members 9, 9, .... are formed as hollow-resilient metallic members so that any torque change may be absorbed and any generation of a play gap which would be caused by elongation of the belt may be prevented by the resiliency thereof. Accordingly, in the illustrated example, each of the intermediate members 9, 9 .... is a hollow slender resilient metallic roller. As shown in Figure 5, the receiving surface 14 is formed to have opposite lateral side walls 14b, 14b arranged to be in abutment with lateral end surfaces of each intermediate member 9, and thereby the respective V-shaped metalic members 8, 8, .... may be restricted against movement in the lateral directions, rsulting intheir smooth contact with each of the V-pulleys 2, 4. In the foregoing example, the engaging surface 10 is so arranged as to be brought into pressure contact with the inner surface of the metallic belt 7, but it can be that, as shown in Figure 8, for instance, the metallic belt 7 is a nearly V-shape in section that is gradually narrower towards the inside, and the engaging surface 10 is a nearly Vshape in section that conforms thereto. With this arrangement, when the respective V-shaped metallic members 8, 8, .... are moved outwards, the engagement between the metallic belt 7 and each of the Vshaped metallic members 8, 8, .... is carried out at their respective V-shaped surfaces, so that the connecting force between the two is increased. In more detail, if the engaging surface 10 is composed of a flat plane 10a facing the inner surface of the metallic belt 7 and taper surfaces lOb, lOb on both lateral sides thereof, then even in an occasion where the flat plane 10a is not brought into pressure contact with the inner surface of the metallic belt 7, as shown in Figure 9, the metallic belt 7 is wedged between the taper surfaces lOb, lOb and a good connection between the belt 7 and the V-shaped metallic member 8 can be obtained. In all the forms illustrated, in order to improve the bending property of the metallic belt 7 by uniformly distributing the stresses applied to the belt at the time of bending thereof at the V-pulleys, the same is composed of plural steel belt members 7a, 7a, .... which are plates of different thicknesses which are so put one upon another in layers as to be gradually thinner towards the inside. Additionally, the example shown in Figure 8 may be further modified as shown in Figure 10 wherein, in order to minimise damage to the innermost thinnestmebber 7a possibly caused by the action of side pressures, lateral corner edge portions of the nearly V-shaped engaging surface 10 are formed with curved portions lOc, lOc, so that the innermost layer 7a is not acted upon by the side pressures. Regarding the decrease in thickness of the plates 7a, 7a . . . -, in more detail, the maximum bending stress 6max is expressed by the following formula: max 6 may = M/I x t/2, where the bending moment is M, the second moment of area is I and the thickness is t. Thus, if the inner layer metallic plate 7a is decreased in thickness by the increasing amount of the bending moment M, there is no difference in the maximum bending stress between an inner layer plate and an outer layer plate, and it can be prevented that the inner layer metallic plate 7a is fatigued earlier than the outer layer metallic plate 7a by repeated bending actions. Thus, by providing that the metallic plates ccnstituting the metallic belt are decreased in thickness towards the inside, the stresses applied to the belt at the time of bending thereof at the V-pulleys can be uniformly distributed, and the useful life of the belt can be elongated. In the modification shown in Figure 11, the hoop-configuration belt members 7a, 7a, .... constituting the metallic belt 7 are so put one upon another in layers as to be gradually narrower towards the innermost side so that each of both lateral sides surfaces of the metallic belt 7 are, overall in the form of a stepped V-shape in section, and each taper surface Ila of the engaging surface 10 is a stepped V-shape in section comforming thereto. With this arrangement, the metallic belt 7 is in engagement, at respective hoop-configuration belt members 7a, with the engaging surface 10 so that the connecting force between the two can be increased as a whole. By arranging in the present V-belt assembly that when respective V-shaped metallic members are brought into engagement with respective V-pulleys, the metallic members are forced to move outwards to be brought into pressure contact connection with the inner circumferential surface of the metallic belt, the connection of the metallic members with the metallic belt can be increased in comparison with a V-belt assembly in which the V-shaped metallic members are connected only through the intermediate members to the metallic belt.

Claims: CLAIMS 1. A V-belt transmission in which an endless metallic belt (7) is provided with a large number of V-shaped metallic members (8,8....), each having an engaging surface (10) facing the metallic belt, the metallic members being disposed in an array along the lengthwise direction of the endless metallic belt so as to make, as a whole, a V-belt assembly, this V-belt assembly being applied between a driving V-pulley (2) and a driven V-pulley (4) so as to effect power transmission therebetween; ahd a large number of intermediate members (9,9,....) so interposed between respective adjacent metallic members (8,8, ....) and positioned inside the metallic belt (7) as to be fastened together from the outer periphery thereof with the metallic belt; characterised in that each of the V-shaped metallic members (8,8, ....) is so held between a corresponding two of the intermediate members (9,9 ) which are located on mutually opposite sides of the metallic member (8) in the lengthwise direction of the metallic belt (7) as to be movable inwards and outwards so that when the respective V-shaped metallic members (8,8,....) are brought into engagement with either of the V-pulleys (2, 4) the metallic members (8,8,....) are pushed by the V-pulley (2 or 4) to be moved outwards to be brought into pressure contact connection, at their engaging surfaces (10), with the metallic belt (7). 2. A V-belt transmission as claimed in claim 1, wherein a contact surface of each of the intermediate members (9,9 ) for each of the metallic members (8,8,....) is in the form of an arc in section. 3. A V-belt transmission as claimed in claim 1 or 2, wherein at least some of the intermediate members (9,9,....) are hollow resilient metallic members. 4. A V-belt transmission as claimed in claim 1, 2 or 3, wherein the metallic belt (7) is in such a nearly V-shape in section that it is gradually narrower towards the inside, and the engaging surfaces (10) of the metallic members (8,8,....) are nearly V-shape in section conforming thereto. 5. A V-belt transmission as claimed in any one of the preceding claims, wherein the metallic belt (7) is formed of plural hoop-configuration belt members (7a, 7a,....) which are gradually decreased in width towards the inside and which are put one upon another in layers to be in a stepped V-shape in section; and wherein the engaging surfaces (10) of the metallic members (8, 8,....) are of stepped V-shape in section nearly corresponding thereto. 6. A V-belt transmission as claimed in claim 5, wherein the belt member (7a,7a,....) are gradually decreased in width stepwise. 7. A V-belt transmission as claimed in any one of the preceding claims, wherein each of the metallic members (8,8,....) is provided with a groove (11), which is open outwardly and which has at its bottom portion the engaging surface (10), each metallic member (8,8,....) being mounted, at its groove (11), on the metallic belt (7) from inside; and wherein a retainer (13) facing the outer surface of the metallic belt (7) is fixedly provided in the groove (11) so that each of the metallic members (8,8,....) is prevented from coming off inwards from the belt (7). 8. A V-belt transmission as claimed in any one of the preceding claims, wherein the metallic belt (7) comprises plural endless metallic plates (7a,7a,....) put one upon another in layers, these plates being decreased in thickness towards the inside.

Inventors: HATTORI, TORAO
Applicants: HONDA GIKEN KOGYO KABUSHIKI KAISHA
Application year: 1984
Main classification: F16H9
IPC codes: F16G5, F16H9