Structure of sealing air valves for split rim type wheels

A structure for sealing air valves for split rim type wheels having an outer split rim member with a hole therein passing through a first end surface. The hole is provided with a screw thread. An inner split rim member has a passage therethrough from the periphery to a second end surface which butts with the first end surface of the outer split rim member. A sealing member is disposed in the hole, and an air valve is threadedly engaged in the hole to compress the sealing member against the second surface of the inner split rim member.

The present invention relates generally to structures of sealing air valves 
for split rim type wheels using tubeless tires. 
More particularly, the present invention relates to a structure of sealing 
air valves wherein the sealing of an air valve is made simple and 
positive, the assembly and disassembly of the air valve are simplified, 
the assembling workability is improved, and maintenance is easy. 
BACKGROUND OF THE INVENTION 
A split rim type wheel in which the rim is split into two split rim members 
in the direction of the axle is adopted because the assembly of the tire 
is simple. However, when a tubeless tire is used on it, the sealing of the 
jointing surfaces of the split rim members will be a problem, and the 
sealing of the valve part for injecting air will also be a problem. 
In sealing the jointing surfaces of the split rim members, there is taken, 
for example, a sealing means wherein a projection is made on one or both 
jointing surfaces, a step part to receive it is made on the other jointing 
surface, an O-ring is inserted in a clearance made between them and the 
split rim members are screwed and fastened to each other in the direction 
of the axle so as to elastically deform said O-ring. 
On the other hand, because the air valve is generally provided in the 
direction of the axle from the outside surface of the rim, the sealing 
means for the air valve is difficult to seal. 
A sealing means is known, for example, such as to make a hole reaching the 
interior of an inside member from an outside member forming a split rim 
and to interpose a sealing member in this hole to seal the valve. In case 
such structure is adopted, when the split rim is shaped by casting, it 
will be necessary not only to make a through hole in the split rim member 
on the valve fitting side, but also to form a recess in the other split 
rim member and to provide a seating part for the sealing member. 
Therefore, there will be many mechanical steps which are troublesome and 
complicated. Precision in fitting the recess to the through hole will be 
required, and excess working steps will be required for the manufacture of 
the rim. It is also necessary to provide such rim with a passage 
communicating with the interior of the tire. When such passagerecess and 
sealing member seating part are formed, the thickness of such part of the 
rim will become so large as to disadvantageously increase the weight of 
the wheel. Further, by the above, the air valve must be assembled and 
sealed simultaneously with the assembling of the split rim members, and 
the assembling of the tire is therefore difficult to accomplish and is 
troublesome and complicated. Further, in case the air valve fails and has 
to be replaced, the valve will not be able to be simply removed and 
replaced. 
SUMMARY OF THE INVENTION 
In view of the above problems in sealing an air valve when a tubeless tire 
is used on a split rim type wheel, the present invention is provided to 
effectively solve such problems. 
An object of the present invention is to provide a structure of sealing air 
valves wherein an air valve can be sealed as simply and positively as 
possible, and can be assembled and disassembled simply, and the 
maintenance of the air valve is easy. 
Another object of the present invention is to provide a structure of 
sealing air valves wherein an air valve can be sealed positively by only 
drilling and threading steps without requiring such operations as making a 
seating part and recess for sealing the valve in the rim, and the 
manufacture of the rim is simplified. 
According to the present invention, a passage communicating with the 
interior of a tubeless tire and an opening on a second end surface jointed 
with a first end surface of an outside member is made in an inside member 
forming a split rim type wheel, a screw fitting hole is formed through the 
outside member, these inside and outside members are connected with each 
other through fastening screws or the like, and an air valve is screwed 
through a sealing member at the tip into said screw fitting hole so that 
the sealing member may be pressed in contact with the tip of the valve and 
the jointing surface of the inside member opposed to it to seal the valve. 
Therefore, according to the present invention, the air valve can be sealed 
and fitted by being screwed through the sealing member into the screw 
fitting hole opened on the outside surface of the assembled split rim. 
Thus, because the valve is sealed simultaneously with the valve screwing 
fitting work, the valve sealing work and valve fitting work can be made as 
simple as possible and, because the valve is fitted after the split rim 
members are assembled, even after the tire is fitted, the valve can be 
simply sealed and fitted. Further, the valve can be simply replaced and is 
very convenient to maintain. 
Further, according to the present invention, the air valve can be sealed by 
providing only one member forming the rim with an air passage and the 
other member with a screw hole. It is not necessary to specially form a 
recess or groove for inserting the sealing member for sealing the valve. 
The shaping of the split rim is simplified and because no recess or groove 
is provided as mentioned above, it is not necessary to form the jointing 
part of the rim to the thick, and thus the weight of the wheel can be 
reduced. 
Further, according to the present invention, there can be obtained a 
structure of sealing air valves wherein, as the air valve is screwed in so 
that the sealing member may be pressed in contact with the jointing 
surface of the split rim member by the tip of the air valve, the air valve 
can be positively sealed. The sealability is excellent, while the fitting 
is simple. 
Preferred embodiments of the present invention shall be explained in detail 
hereinbelow with reference to the accompanying drawings.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
In FIGS. 1 to 3 showing the first embodiment, a rim 30 is split into two 
members 10 and 20 in the direction of the axle, and is shaped by casting 
or the like. The split rim member 10 is an outer wheel part appearing 
outside the car, and the other member 20 is an inner wheel part hidden 
inside. Ear pieces 12 and 22, which are parts to lock bead parts 101 and 
102 on the left and right of a tire 100 by rising upwardly, are integrally 
formed at the outer ends of the respective split rim members 10 and 20. 
Because an air valve is fitted from outside, the length in the direction of 
the axle of a base part 11 of the outer member 10 is made shorter than the 
length in the direction of the axle of a base part 21 of the inner member 
20. The ear pieces 12 and 22 are provided at the symmetrical outside ends 
of the respective base parts 11 and 21. The jointing parts of the base 
parts 11 and 21 of the respective members 10 and 20 are engaged 
concavo-convexly with each other by making one convex part 23 and a 
concave part 13. The end edge of the convex part 23 is diagonally cut to 
form a space which is triangular in cross-section within the 
concavo-convex engaging part. A sealing member 60, such as an O-ring, is 
inserted in said space. The split members 10 and 20 are screwed and 
fastened in the direction of the axle to seal the rim 30 on the periphery. 
Extensions 14 and 24 are symmetrically formed inwardly in the radial 
direction on the inner periphery of the butted jointing parts of the split 
members 10 and 20, are provided over the entire inner periphery of the 
split members 10 and 20, and are screwed and fastened in the direction of 
the axle with bolts 71 and nuts 72, as shown in FIG. 3, in a plurality of 
places radially provided on the periphery. 
The extension 14 of the outside split member 10 is shaped as integrally 
continued with a wheel disc part 15 which is connected with the base 11 as 
integrally continued with the extension 14 in the peripheral side part. 
The disc part 15 is provided with windows 15a for weight reduction and 
decoration, a plurality of radial hub fitting holes 15b, and an axle 
inserting hole 15c. 
A part of the extension 24 of the inside split member 20 is provided with a 
radial passage 26, opened on the outer periphery at one end to communicate 
with the space within the tire 100, and closed at the other end so as to 
be connected in the closed bottom with a communicating passage 27 
intersects perpendicularly with the bottom of the passage 26 at the inner 
end, and opens on the jointing end surface of the extension 24 at the 
outer end. 
In the position of the coincidence of the extension 14 of the outside split 
member 10 with the communicating passage 27, there is provided a fitting 
hole 16 of a large diameter opening on the outside surface and passing 
through the jointing inside surface from the outside surface. A screw is 
formed in the part toward the outside surface of this fitting hole 16 to 
form a screw hole part 16a. 
An air valve 40 has a male screw 41a formed on the outer periphery of a 
valve stem 41 and is screwed into the fitting hole 16 in the outside 
member 10 integrally connected and assembled as illustrated. A step part 
42 of a diameter smaller than in other parts is formed in advance in the 
tip part of the valve stem 41 of the valve 40 so that, when the smaller 
diameter tip part of the valve 40 contacts the jointing surface of the 
extension 24 of the inside member 20 in screwing it, a ring-shaped space 
may be formed between the inner periphery in the bottom of the fitting 
hole 16 and the tip part of the valve 40. In screwing the air valve 40 
into the fitting hole 16, a ring-shaped sealing member 50 is fitted in 
advance to the periphery of the smaller diameter step part at the tip, and 
then said valve 40 is screwed into the fitting hole 16. As the valve stem 
41 is screwed in, the sealing member 50 at the tip will contact the 
jointing end surface of the extension 24 of the inside member adjacent a 
seat portion surrounding the opening of passage 27 on the jointing end 
surface of extension 24 (FIG. 2), and will be compressed to be deformed 
between the jointing end surface and the smaller diameter step part 42 to 
act as a seal. At the same time, an air feeding passage 43 provided within 
the valve stem 41 of the air valve 40 will coincide and communicate with 
the communicating passage 27 opening on the jointing surface, and the 
connecting part of these passages 43 and 27 will be sealed with the 
sealing member 50 on the outer periphery. 
The sealing member 50 has an outside diameter substantially equal to the 
outside diameter of said stem as fitted to the smaller diameter step part 
42 at the tip of the valve stem 41, and is so set as to be larger in the 
axial direction of valve stem 41 than the length of the smaller diameter 
step part 42 in the width direction, i.e., the compressing direction. 
The air valve can be simply and positively sealed by merely screwing the 
air valve 40 in with the sealing member 50 interposed after assembling the 
split rim members 10 and 20 and assembling and fitting the tire. 
In the drawings, the reference numeral 44 indicates a cap of the air valve, 
and 103 indicates a reinforcing member embedded in the tire bead parts 101 
and 102. 
FIG. 4 shows a modified embodiment which is fundamentally of the same 
structure as the first embodiment and in which therefore the same numerals 
are used for the same respective parts. 
In this embodiment, as shown in the drawing, a flat protector 110 and bead 
stopper 120 are fitted to enclose the rim on the outer periphery within 
the tire 100 to increase the safety of the tire 100. The flat protector 
110 is formed of rubber or the like, is formed to be C-shaped in 
cross-section, is provided with a plurality of radial holes 111 on the 
periphery, has leg parts 112 and 113 on both sides in contact with the 
inside surfaces of the respective tire beads 101 and 102, and has the bead 
stopper 120 as a spacer inserted on the outer peripheral surface of the 
rim 30 between the insides of leg parts 112 and 113. This bead stopper 120 
is formed of plastics. Therefore, the passage 26 provided within the 
extension 24 of the split rim member 20 will be closed by the stopper 120. 
A groove 28 is formed in the axial direction on the outer periphery of the 
base part of the split rim member 20 to be present at the opening end of 
the passage 26, and to form a passage in the axial direction between the 
bottom surface of the bead stopper 120 and the outer peripheral surface of 
the rim. Communicating passages 121 are formed in the radial direction in 
the part corresponding to said groove 28 of the bead stopper 120. In the 
illustration, two of such passages 121 are provided. 
The air fed through the air valve 40 will be fed into the space within the 
tire 100 through the passage 26, groove 28 and passages 121 in the bead 
stopper 120. Therefore, even in the tire fitted with the bead stopper 120 
or the like, air will be able to be injected without trouble. 
According to the present invention, the air valve can be simultaneously 
fitted and sealed by merely screwing in the air valve through the sealing 
member after assembling the split rim members 10 and 20 and assembling and 
fitting the tire. The air valve can be simply replaced by unscrewing and 
removing it out of the fitting hole, and screwing in a new valve together 
with a sealing member. Further, as shown from the illustration, in the 
present invention, it is not necessary to provide the split rim members 
with a seating part or recess for fitting the sealing member 50. Only a 
screw fitting hole need be made in one of the split members, and a passage 
made in the other.