JP6711184B2 - Chain-type continuously variable transmission - Google Patents

Description

The present invention relates to a chain type continuously variable transmission mechanism that is configured by winding an endless chain around a V-groove pulley so as to be continuously variable, and particularly increases a friction coefficient between the endless chain and the V-groove pulley. The present invention relates to a technique for improving the transmission efficiency of a chain type continuously variable transmission mechanism.

In the chain type continuously variable transmission mechanism, an endless chain is usually hung over the V groove of the pulley to enable power transmission, and during this power transmission, the interval between the axially opposed sheaves defining the pulley V groove is changed. By changing the groove width of the pulley V groove, the diameter of the circular arc around which the endless chain is wound around the pulley is continuously changed, so that the above-described continuously variable transmission is possible.

On the other hand, in the endless chain, a large number of link plates are sequentially connected by the link pins inserted into the link pin insertion holes at both ends of the link plates in a continuous ring shape.
The both axial end faces of each link pin are inclined so as to make surface contact with the conical sheave faces of the axially opposed sheaves that provide the side walls of the pulley V groove, and the inclined end faces of the link pin of the pulley are formed. The above power transmission is made possible by frictional contact with the facing sheave surface.

By the way, when the link pin of the endless chain is wound around the V-groove pulley and enters the V-groove pulley, the oil film that will be interposed between the inclined both end surfaces of the link pin and the sheave surface facing the V-groove pulley. Due to the squeeze effect, the friction coefficient between the link pin and the V-groove pulley (sheave surface) decreases, and the traction force (friction force) between the two decreases, resulting in poor transmission efficiency.

In order to solve this problem, conventionally, as described in Patent Document 1, the friction contact area of the endless chain (link pin) is respectively formed on the facing sheave surfaces of the axially opposite sheaves on which the endless chain (link pin) frictionally contacts. Provide a fine circumferential groove extending in the circumferential direction over the whole,
The presence of such fine circumferential grooves reduces the generation of the oil film to increase the coefficient of friction between the link pin and the V-groove pulley (sheave surface), thereby reducing the traction force (friction force) (decreasing the transmission efficiency). ) Has been proposed.

The following proposal is also made in Patent Document 1.
The above-mentioned tendency that the friction coefficient between the link pin and the V-groove pulley (sheave surface) is reduced due to the oil film existing between the inclined both end surfaces of the link pin and the sheave surface facing the V-groove pulley is It is known that it becomes more prominent on the radially inner side of the sheave surface.

From this, in Patent Document 1, the depth of the fine circumferential groove on the radially inner side of the sheave surface is made deeper than the depth of the fine circumferential groove on the radially outer side of the sheave surface, whereby the sheave. A technical proposal has also been made that suppresses the increase of the thickness of the oil film on the radially inner side of the surface and reduces the occurrence of the oil film (the reduction of the friction coefficient) on the radially inner side of the sheave surface as required. There is.

JP, 2005-117783, A

However, the following problems cannot be avoided by a measure such that the depth of the fine circumferential groove is deeper on the radially inner side of the sheave surface than on the radially outer side of the sheave surface as in the above-mentioned conventional technique.
That is, the width and the depth of the fine circumferential groove required for realizing the reduction of the oil film are minute in the order of μm, and the fine circumferential groove is finely processed by, for example, polishing with a grindstone. In some cases, the process of making the depth of the fine circumferential groove having the smallest arrangement pitch in the radial direction of the sheave surface different between the radially inner peripheral side and the outer peripheral side of the sheave surface is a manufacturing robustness. Another difficulty arises that it is difficult to obtain sex.

In view of the above-mentioned problem of robustness, the present invention, instead of making the depth of the fine circumferential groove provided on the sheave surface different between the radially inner peripheral side and the outer peripheral side of the sheave surface, V in the radial direction of the sheave surface. The sheave face diameter that tends to thicken the oil film by making the installation density of the closed loop fine circumferential groove arranged individually concentrically with the rotation axis of the grooved pulley different between the radially inner side and the outer side of the sheave face. An object of the present invention is to improve the transmission efficiency of a chain type continuously variable transmission mechanism by making it possible to reduce the generation of an oil film (reduction of friction coefficient) on the inner peripheral side in the direction as required.

For this purpose, the chain type continuously variable transmission mechanism according to the present invention is constructed as follows.
First, the chain type continuously variable transmission mechanism which is the premise of the present invention will be described.
It consists of an endless chain and a V-groove pulley around which this endless chain is continuously variable.
The continuously variable transmission is possible by changing the interval between the axially opposed sheaves that define the V groove of the pulley.

The present invention provides such a chain type continuously variable transmission mechanism,
Arranged concentrically with the rotation axis of the V-groove that extends in the circumferential direction over the entire frictional contact area of the endless chain on each of the opposite sheave surfaces of the axially opposite sheave with which the endless chain makes frictional contact. Each of them is provided with a closed loop fine circumferential groove, and the pulley radial direction arrangement pitch of the inner circumferential fine circumferential groove on the radially inner side of the sheave surface of the fine circumferential groove is set to the sheave surface The inner peripheral fine circular groove is made smaller than the pulley radial arrangement pitch of the outer peripheral fine circular grooves on the outer peripheral side in the radial direction, and the fine peripheral circular grooves on the outer peripheral side are formed on the outer peripheral side in the radial direction of the sheave surface. It is characterized by a configuration that is denser than the grooves.

In the above-mentioned chain type continuously variable transmission mechanism of the present invention, in the fine circumferential groove provided on the opposing sheave surface over the entire region where the endless chain makes frictional contact, on the radially inner side of the sheave surface. Since the inner circumferential fine circumferential groove is arranged at a higher density than the outer fine circumferential groove on the radial outer side of the sheave surface,
For the above-mentioned reason, the oil film can be blocked as required by the inner circumferential side fine circumferential groove of the high density arrangement even on the radially inner side of the sheave surface where the oil film tends to be thick, and the endless chain and the facing sheave The generation of an oil film between the surface and the surface can be blocked as required over the entire area where both of them make frictional contact, and the friction coefficient is improved so that the slip due to the oil film is reduced over the entire area of the frictional contact, In addition, the contact surface pressure between the endless chain and the facing sheave surface becomes relatively high, which also increases the friction coefficient between the two regardless of the pulley ratio, and the chain type stepless The transmission efficiency of the speed change transmission mechanism can be improved.

Further, due to the increase in the friction coefficient, the chain clamping pressure by the facing sheave surfaces, which is necessary to achieve the required friction coefficient between the endless chain and the facing sheave surfaces, can be low, and the energy consumption for that is reduced. It is also possible to improve the durability of the chain type continuously variable transmission mechanism.

Since the above effect is obtained by arranging the inner circumferential side fine circumferential groove of the sheave surface at a higher density than the outer circumferential side fine circumferential groove, the fine circumferential groove of the conventional type Compared with the case where the same problem is solved by changing the specifications of the fine circumferential groove where the depth is different on the inner circumference side and the outer circumference side, the time required for processing is shorter and the cost is lower. It is also possible to achieve the effect that the robustness of is easily obtained.

It is a schematic side view which illustrates the chain type continuously variable transmission mechanism to which the idea of this invention can be applied. FIG. 2 is a detailed side view showing a winding transmission section on the secondary pulley side of the chain type continuously variable transmission mechanism shown in FIG. FIG. 3 is a vertical cross-sectional view showing details of a secondary pulley-side chain winding transmission section shown in FIG. FIG. 4 is an overall perspective view showing a link pin of the endless chain in FIGS. 1 to 3. 2 is a schematic side view similar to FIG. 1, showing a chain type continuously variable transmission mechanism according to a first embodiment of the present invention. FIG. FIG. 5 is an enlarged cross-sectional view of a main part showing the primary pulley sheave and the secondary pulley sheave of the chain type continuously variable transmission mechanism shown in FIG. 5, and (a) shows the inner peripheral side of the sheave surface indicated by α in FIG. A cross-sectional view taken along the line A-A, and an enlarged cross-sectional view of an essential part shown in the direction of the arrow, (b) shows the outer peripheral side of the sheave surface indicated by β in FIG. FIG. 3 is an enlarged cross-sectional view of a main part as seen in the direction of the arrow.

Hereinafter, embodiments of the present invention will be described in detail based on examples shown in the drawings.
<Structure of the first embodiment>
1 to 3 show a chain type continuously variable transmission mechanism to which the idea of the present invention can be applied,
FIG. 1 is a schematic side view of the chain type continuously variable transmission mechanism 10, and FIGS. 2 and 3 are a detailed side view and a longitudinal sectional view of a winding transmission portion on the secondary pulley side thereof, respectively.

In FIG. 1, 11 is a primary pulley that is a drive side pulley of the chain type continuously variable transmission mechanism 10, and 12 is a secondary pulley that is a driven side pulley.
An endless chain 13 is provided so as to span between the primary pulley 11 and the secondary pulley 12, and the chain type continuously variable transmission mechanism 10 transmits power between the primary pulley 11 and the secondary pulley 12 via the endless chain 13. I shall.

Each of the primary pulley 11 and the secondary pulley 12 is provided with facing sheaves 11a and 12a (in FIG. 1, the sheave on the front side is removed and only the sheave on the other side is shown for convenience), which faces each other in the rotation axis direction. Let V-grooves define pulley V-grooves between 11a and opposing sheaves 12a (the pulley V-grooves defined between opposing sheaves 12a are shown in FIG. 3).

As shown in FIGS. 2 and 3, the endless chain 13 has a continuous annular shape in which a large number of link plates 14 are sequentially connected to each other by the link pins 15 in the link pin insertion holes 14a at both ends thereof.
Then, as shown in FIG. 3, the link plate 14 is retained by the retainer pin 16 planted in the link pin 15 with respect to the link pin 15.

The link pins 15 as a whole have a curved back surface 15a as shown in FIG. 4, and the curved back surfaces 15a are back-to-back as shown in FIG. 2 in a pair, and inside the link pin insertion holes 14a at both ends of the link plate 14. Insert into.
As shown in FIGS. 3 and 4, both end surfaces 15b of the link pin 15 are axially opposed sheaves 11a (specifically, both opposed sheave surfaces 11b) that provide pulley V groove side walls of the primary pulley 11 and the secondary pulley 12, respectively. Inclination is made so as to make frictional contact with the axially facing sheave 12a (specifically, the facing sheave surfaces 12b of the two).

Thus, in the endless chain 13, the link pin 15 is sandwiched between the opposing sheaves 11a of the primary pulley 11 (opposing sheave surfaces 11b) and between the opposing sheaves 12a of the secondary pulley 12 (between the opposing sheave surfaces 12b) in the pulley winding area. By being pressed, the power can be transmitted between the primary pulley 11 and the secondary pulley 12.

One of the facing sheaves 11a of the primary pulley 11 is a fixed sheave and the other is a movable sheave whose stroke can be controlled in the axial direction.
The facing sheave 12a of the secondary pulley 12 has a sheave on the same side as the movable sheave of the primary pulley 11 (a sheave on the left side of FIG. 3) as a fixed sheave, and a sheave on the same side as the fixed sheave of the primary pulley 11 (see FIG. 3). The sheave on the right side is a movable sheave whose stroke can be controlled in the axial direction.

Thus, during the power transmission, the movable sheave of the primary pulley 11 is brought closer to the fixed sheave to narrow the pulley V groove width, and at the same time, the movable sheave of the secondary pulley 12 is moved away from the fixed sheave to widen the pulley V groove width. As
In the endless chain 13, the diameter of the winding arc around the primary pulley 11 is increased, and the diameter of the winding arc around the secondary pulley 12 is reduced, and the chain type continuously variable transmission mechanism 10 selects the highest gear ratio selection shown in FIG. It is possible to upshift under continuously variable gear shift to the state.

Conversely, as the movable sheave of the primary pulley 11 is moved away from the fixed sheave to widen the pulley V groove width, and at the same time the movable sheave of the secondary pulley 12 is moved closer to the fixed sheave to narrow the pulley V groove width,
In the endless chain 13, the diameter of the winding arc with respect to the primary pulley 11 is reduced and the diameter of the winding arc with respect to the secondary pulley 12 is increased, and the chain type continuously variable transmission mechanism 10 selects the highest gear ratio as shown in FIG. It is possible to downshift under continuously variable gear shift from the state to the unillustrated lowest gear ratio selection state.

<Measures to increase friction coefficient between link pin and sheave surface>
In order to improve the transmission efficiency of the chain type continuously variable transmission mechanism described above, the inclined both end surfaces 15b of the link pin 15 are brought into frictional contact with the pulley facing sheaves 11a, 12a (opposing sheave surfaces 11b, 12b), and endless. Since the power is transmitted through the chain 13, it is important to increase the friction coefficient between the inclined both end surfaces 15b of the link pin 15 and the pulley facing sheaves 11a, 12a (opposing sheave surfaces 11b, 12b). ..

Here, the friction coefficient between the inclined both end surfaces 15b of the link pin 15 and the pulley facing sheaves 11a, 12a (opposing sheave surfaces 11b, 12b) will be considered.
If there is no oil film between the inclined both end surfaces 15b of the link pin 15 and the pulley facing sheaves 11a, 12a (opposing sheave surfaces 11b, 12b) and both are in full contact, the frictional force between them (friction coefficient ) Continuously changes with a relatively large value between the position where the link pin 15 is wound around the pulley and enters and the position where the link pin 15 is paid out from the winding region of the pulley.

However, the chain type continuously variable transmission mechanism 10 needs to lubricate the transmission part between the primary pulley 11 and the secondary pulley 12 and the endless chain 13, and the inclined both end surfaces 15b of the link pin 15 and the pulley facing sheave 11a. , 12a (opposing sheave surfaces 11b, 12b) have an oil film interposed therebetween.

Therefore, the inclined both end surfaces 15b of the link pin 15 and the pulley opposing sheaves 11a, 12a (opposing sheave surfaces 11b, 12b) do not make full contact, and the inclined both end surfaces 15b of the link pin 15 and the pulley opposing sheaves 11a, 12a ( The frictional force (friction coefficient) between the opposing sheave surfaces 11b and 12b) becomes smaller than the frictional force (friction coefficient) at the time of full contact due to the interposition of the oil film.
Therefore, there is a problem that slippage is likely to occur between the inclined both end surfaces 15b of the link pin 15 and the pulley opposing sheaves 11a, 12a (opposing sheave surfaces 11b, 12b), and the transmission efficiency of the chain type continuously variable transmission mechanism is deteriorated. appear.

This problem is caused by link pin 15 when coasting (inertia) traveling is performed in a region where the winding arc diameter of endless chain 13 with respect to pulleys 11 and 12 is small, that is, at a large pulley ratio (low side pulley ratio). Of the primary pulley sheave 11a (sheave surface 11b) on the radially inner side (hereinafter simply referred to as the inner side) of the primary pulley sheave 11a, and the small pulley ratio (high side pulley). When the driving is performed at a ratio of (2), the inclined end surfaces 15b of the link pin 15 and the inner peripheral side of the secondary pulley sheave 12a (sheave surface 12b) are significantly visible in the contact area.

The reason will be described below.
At the inner peripheral side of the sheave surface of the primary pulley sheave 11a and the inner peripheral side of the sheave surface of the secondary pulley sheave 12a, the winding radius of the endless chain 13 is small, and the chain contact length with respect to the sheave surfaces 11b and 12b (the chain relative to the V-groove pulley is Since the winding length) is short and the peripheral speed of the endless chain 13 is high, the amount of oil film that can be accommodated between the inner peripheral side of the sheave surfaces 11b, 12b and the inclined end surfaces 15b of the link pin 15 is small, and the sheave is small. Under the condition that the clamping force of the endless chain 13 (link pin 15) by the surfaces 11b and 12b is the same, the oil film on the inner peripheral side of the sheave surfaces 11b, 12b becomes the outer peripheral side in the radial direction of the sheave surfaces 11b, 12b (hereinafter simply referred to as the outer periphery). It is thicker than the side).

On the other hand, on the outer peripheral side of the sheave surfaces 11b and 12b, the sheave surface is mainly caused by a large chain winding radius and a long chain contact length with the sheave surfaces 11b and 12b (chain winding length with respect to the V-groove pulleys 11 and 12). A large amount of oil film can be stored between the outer peripheral side of 11b, 12b and the inclined end surfaces 15b of the link pin 15, and the oil film on the outer peripheral side of the sheave surfaces 11b, 12b is thinner than the inner peripheral side of the sheave surfaces 11b, 12b. Tends to become.

For these reasons, the decreasing tendency of the friction coefficient between the link pin 15 and the V-groove pulleys 11 and 12 (the sheave surfaces 11b and 12b) becomes more prominent toward the inner peripheral side of the sheave surfaces 11b and 12b.

In view of the above facts, in the first embodiment of the present invention, the oil film interposed between the inclined both end surfaces 15b of the link pin 15 and the pulley facing sheaves 11a, 12a (the sheave surfaces 11b, 12b) is provided as follows. It is possible to cut off as much as required over the entire traction transmission area of the surfaces 11b, 12b, so that the coefficient of friction between the link pin inclined both end surfaces 15b and the pulley facing sheaves 11a, 12a (sheave surfaces 11b, 12b) can be determined. The transmission efficiency of the chain type continuously variable transmission is improved by enlarging it as required in the entire traction transmission area of 11b and 12b.

That is, in the present embodiment, in view of the above-described oil film generation situation on the inner peripheral side and the outer peripheral side of the V-groove pulley facing sheaves 11a, 12a (sheave surfaces 11b, 12b), as shown in FIG. Fine sheave grooves 21 extending in the pulley circumferential direction are provided on the sheave surfaces 11b and 12b of 12a, respectively, over the entire region in which the endless chain 13 (link pin end inclined surfaces 15b) frictionally contacts. The fine circumferential groove 21 is particularly constructed and arranged as follows.
The winding state of the endless chain 13 shown in FIG. 5 is the same as that of FIG. 3, in which the endless chain 13 is wound around the primary pulley 11 and the secondary pulley 12 with the same circular arc diameter. Is.

In the present embodiment, these fine circumferential groove 21 are individually closed loop circular fine circumferential grooves, and in order to extend these circular fine circumferential groove 21 along the moving direction of the link pin 15, preferably, A true circular groove concentric with the axial center Op of the primary pulley 11 and the secondary pulley 12.
All of these circular fine circumferential groove (true circular groove) 21 is the inner peripheral side of the sheave surfaces 11b, 12b, which is the α region in FIG. 3, as a cross section taken along the line AA in FIG. As shown in FIG. 6(b), the outer peripheral side of the sheave surfaces 11b, 12b, which is the β region of FIG. 3, is clearly shown in FIG. 6(b) as the BB cross section of FIG. It is assumed that

However, in the circular fine circular groove (true circular groove) 21, the interval (pulley radial pitch) between the circular fine circular grooves 21 adjacent to each other in the radial direction of the pulleys 11 and 12 is shown in FIG. 6(a). , (b), the inner peripheral side α of the sheave surfaces 11b, 12b and the outer peripheral side β are different, that is, the pulley radial direction of the circular fine circumferential groove 21 on the inner peripheral side α of the sheave surfaces 11b, 12b. The pitch Pin is arranged so as to be smaller than the pulley radial pitch Pout of the circular fine circular groove 21 on the outer peripheral side β of the sheave surfaces 11b, 12b, and the circular fine circular groove 21 is formed on the inner peripheral side α. Place more densely than on side β.
The circular fine circumferential groove (true circular groove) 21 has a width W and a depth D of, for example, a micrometer order in consideration of the installation requirements, and can be engraved by grinding with a grindstone or the like. ..

Here, the pulley radial pitch Pin (radial array density) of the circular fine circumferential groove 21 on the inner peripheral side α of the sheave surfaces 11b, 12b, and the pulley diameter of the circular fine circular circumferential groove 21 on the inner peripheral side α The direction pitch Pin (radial array density) and the pulley radial pitch Pout (outer peripheral radial array density) of the circular fine circumferential groove 21 on the outer peripheral side β are respectively the inner peripheral side α and the sheave surfaces 11b and 12b. According to the degree of demand for the removal of the oil film on the outer peripheral side β (friction coefficient increase demand degree), it is determined that the demand is fulfilled.

The pulley radial direction pitch of the circular fine circumferential groove 21 between the inner peripheral side α and the outer peripheral side β is the inner peripheral side pitch Pin (inner peripheral side radial array density) and the outer peripheral side pitch Pout (outer peripheral side diameter). Directional arrangement density), and this intermediate value is also the degree of demand for removal of the oil film in the region between the inner peripheral side α and the outer peripheral side β of the sheave surfaces 11b, 12b (friction coefficient increase demand degree) According to, the request is decided to be realized.

In the above description, the pulley radial pitch of the circular fine circumferential groove 21 is different between the inner peripheral side region α, the outer peripheral side region β, and the intermediate region between them. The degree of demand (degree of demand for increasing the friction coefficient) is small on the outer peripheral side β and increases as it goes to the inner peripheral side α.
When determining the pulley radial pitch of the circular fine circumferential groove 21, as going from the innermost circumferential fine circumferential groove to the outermost fine circumferential groove of the circular fine circumferential groove 21, Needless to say, it is good to gradually increase the pulley radial pitch of the circular fine circumferential groove 21.

In this case, from the innermost peripheral side groove to the outermost peripheral side fine circular fine circumferential groove 21, all of the circular fine circular groove 21 are required for the removal of the oil film described above (increased friction coefficient). Therefore, the transmission efficiency of the chain type continuously variable transmission mechanism can be efficiently increased without providing a wasteful circular fine circumferential groove 21.

<Effect of the first embodiment>
According to the configuration of the above-described first embodiment, the sheave surfaces 11b and 12b of the sheaves 11a and 12a that face each other in the axial direction of the pulley are covered over the entire area in which the endless chain 13 (the inclined surfaces 15b at both ends of the link pin 15) frictionally contacts. The circular fine circular groove 21 is provided with a circle, and the pulley radial pitch Pin of the inner fine circular groove of these circular fine groove 21 is defined as the pulley radial pitch Pout of the outer fine circular groove. Since the inner circumferential side fine circumferential groove is arranged at a higher density than the outer circumferential side fine circumferential groove,
As described above, even on the inner peripheral side of the sheave surface where the oil film tends to be thick, the oil film can be blocked as required by the inner peripheral side fine circumferential groove of the high density arrangement.

Therefore, the oil film generated between the endless chain 13 and the facing sheave surfaces 11b, 12b can be blocked as required over the entire area in which both of them make frictional contact, and the slip due to the oil film causes the entire frictional contact area. The friction coefficient is improved so as to be reduced over a period of time, and the contact surface pressure between the endless chain 13 and the facing sheave surfaces 11b, 12b is relatively increased. It can be increased over the entire range regardless of the pulley ratio, and the transmission efficiency of the chain type continuously variable transmission mechanism can be improved.

Further, due to the increase in the friction coefficient, the chain clamping force by the facing sheave surfaces 11b, 12b, which is necessary to achieve the required friction coefficient between the endless chain 13 and the facing sheave surfaces 11b, 12b, may be low. The energy consumption of the chain type can be reduced and the durability of the chain type continuously variable transmission can be improved.

Since the above effect can be obtained by arranging the inner circumferential side fine circumferential groove of the sheave surfaces 11b, 12b at a higher density than that of the outer circumferential side fine circumferential groove, the fine circumferential circumference as in the conventional case is obtained. Compared to the case where the same problem is solved by changing the specifications of the fine circumferential groove where the depth of the groove is different between the inner circumference side and the outer circumference side, the processing time is shorter and the cost is lower. In addition, it is possible to achieve the effect that manufacturing robustness is easily obtained.

Further, as described above in this embodiment, when determining the pulley radial pitch of the circular fine circumferential groove 21, the innermost fine groove of the circular fine groove 21 to the outermost fine groove of the circular fine groove 21 are determined. In the case where the pulley radial pitch of the circular fine circumferential groove 21 is continuously changed so that the radial pitch of the circular fine circular groove 21 gradually increases toward the circumferential groove,
From the innermost peripheral side to the outermost peripheral side of the circular fine circumferential groove 21, all of the circular fine circular grooves 21 have the above-mentioned degree of demand regarding the elimination of the oil film (degree of increase in friction coefficient). Since it can be realized without excess or deficiency, it is possible to efficiently increase the transmission efficiency of the chain type continuously variable transmission mechanism without providing wasteful circular fine circumferential groove 21.

<Second embodiment>
Although not shown, in the present invention, the fine circumferential groove 21 provided on the sheave surfaces 11b, 12b in the entire region where the endless chain 13 (link pin both end inclined surfaces 15b) contacts is circular as in the first embodiment. Instead of forming into a (perfect circle), it can be formed into one continuous spiral.

That is, in the present embodiment (for convenience, the portions corresponding to those in the first embodiment will be described with the same reference numerals), from the innermost circumferential side fine circumferential groove among the fine circumferential groove on the inner circumferential side α. , One continuous spiral fine circumferential groove 21 extending spirally to the outermost fine circumferential groove of the fine circumferential groove on the outer peripheral side β is provided on the sheave surfaces 11b, 12b. The spiral fine circumferential groove 21 is provided over the entire end chain contact region, and is arranged concentrically with the rotation axis Op of the V-groove pulleys 11 and 12.

The pitch of the spiral fine circumferential groove 21 in the pulley radial direction is gradually increased from the inner side of the pulley radial direction toward the outer side of the pulley radial direction, or the inner peripheral side region α and the outer peripheral side are arranged. By making the region β and these intermediate regions different from each other based on the same idea as in the first embodiment, the inner circumferential side fine circumferential groove is arranged at a higher density than the outer circumferential side fine circumferential groove. ..
When processing the spiral fine circumferential groove 21, the processing is started from the wire ring portion on the innermost peripheral side in the pulley radial direction, and the processing is advanced to the wire ring portion on the outermost peripheral side in the pulley radial direction. A spiral fine circumferential groove 21 is formed.

<Effects of the second embodiment>
Also in this embodiment, the spiral fine circumference is provided over the entire area where the endless chain 13 (both end inclined surfaces 15b of the link pin 15) frictionally contacts the sheave surfaces 11b, 12b of the sheaves 11a, 12a facing the pulley axial direction. A groove 21 is provided, and the arrangement pitch of the spiral fine circumferential groove 21 in the radial direction of the pulley is made smaller on the inner peripheral side of the sheave surfaces 11, 12b than on the outer peripheral side, and the inner peripheral fine circular groove is formed on the outer periphery. Since it is arranged at a higher density than the side fine circumferential groove,
As described above for the first embodiment, even on the inner peripheral side of the sheave surface where the oil film tends to be thick, the oil film can be blocked as required by the inner peripheral side fine circumferential groove of the high density arrangement. Various effects similar to the example can be achieved.

Further, in determining the pulley radial pitch of the spiral fine circumferential groove 21 in this embodiment, as described above, the pitch of the spiral fine circumferential groove 21 in the pulley radial direction is set from the inner radial side of the pulley to the pulley radial direction. When continuously changing the pulley radial pitch of the spiral fine circumferential groove 21 so as to gradually increase toward the outer peripheral side in the radial direction,
From the innermost-circumferential-side wheel portion of the spiral fine circumferential groove 21 to the outermost-circumferential-side wheel portion, all the wheel portions of the helical fine circumferential-groove 21 are respectively excluded from the oil film described in the first embodiment. By satisfying the degree of demand (requirement degree of increasing the friction coefficient) with respect to the spiral fine circumferential groove 21, there will be no unnecessary wire ring portion, and the chain type continuously variable transmission mechanism can be efficiently used. The transmission efficiency of can be improved.

When the spiral fine circumferential groove 21 is processed, the processing is started from the wire ring portion on the innermost peripheral side in the pulley radial direction, and the processing is advanced to the wire ring portion on the outermost peripheral side in the pulley radial direction. To form the fine circular circumferential groove 21,
If the wire ring portion of the spiral fine circumferential groove 21 on the inner diameter side of the pulley in the radial direction of the pulley is required to have high accuracy with respect to the shape and the arrangement pitch of the pulley in the radial direction, the 雖 can also achieve this high accuracy relatively easily. Thus, it is easy to ensure robustness regarding the oil film accommodable amount of the inner peripheral side wheel portion.

<Other Examples>
In both of the embodiments described above, the fine circumferential groove 21 is a true circular groove (first embodiment) or a spiral groove (second embodiment) concentric with the pulley sheaves 11a and 12a. However, if the fine circumferential groove 21 extends in the circumferential direction of the pulley, the above-described effects can be obtained in the same manner.

10 chain type continuously variable transmission
11 Primary pulley
11a Primary pulley sheave
11b Opposing sheave surface
12 Secondary pulley
12a Secondary pulley sheave
12b Opposing sheave surface
13 endless chain
14 Link board
15 link pin
15b Both ends inclined surface
21 Fine circumferential groove

Claims (2)

It consists of an endless chain and a V-groove pulley around which this endless chain is continuously variable.
In the chain type continuously variable transmission mechanism capable of continuously variable transmission by changing the interval between the axially opposed sheaves defining the V groove of the pulley,
Each of the opposed sheave surfaces of the axially opposed sheaves with which the endless chain makes frictional contact is arranged in concentric with the rotation axis of the V-groove pulley over the entire frictional contact area of the endless chain. A circumferential groove is provided, and a pulley radial direction arrangement pitch of the inner circumferential side fine circumferential groove on the radially inner side of the sheave surface of the fine circumferential groove is set on the radial outer side of the sheave surface. A chain characterized in that the inner peripheral fine circumferential groove is arranged at a higher density than the outer peripheral fine circumferential groove by making the outer peripheral fine circumferential groove smaller than the pulley radial array pitch. Type continuously variable transmission mechanism. The chain type continuously variable transmission mechanism according to claim 1,
From the innermost circumferential fine circumferential groove of the inner circumferential fine circumferential groove to the outermost fine circumferential groove of the outer circumferential fine circumferential groove, the fine circumference A chain type continuously variable transmission, characterized in that the pitch of the grooves in the radial direction of the pulley is gradually increased .

Images