JP2005264990A - Belt type continuously variable transmission, belt type continuously variable transmission sheave, and vehicle equipped with the belt type continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a belt type continuously variable transmission capable of preventing sliding of a belt, while minimizing thrust added to the belt. <P>SOLUTION: In the belt type continuously variable transmission 1 transmitting rotating force of a primary side sheave 3 to a secondary side sheave 5 through an endless belt, a continuously variable transmission sheave, and a vehicle equipped with the continuously variable transmission, a belt clipping surface 15 of at least either one of the primary side sheave 3 or the secondary side sheave 5 is plastically deformed by contacting with the belt to smooth surface roughness. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a belt-type continuously variable transmission that transmits the rotational force of a primary-side sheave to a secondary-side sheave via an endless belt, a sheave used in this belt-type continuously variable transmission, and further this belt-type continuously variable transmission In particular, the present invention relates to a structure for preventing belt slippage at the beginning of operation.

There has been proposed a belt type continuously variable transmission for a motorcycle that can adjust a gear ratio steplessly in accordance with a traveling state (see, for example, Patent Document 1).
This type of belt-type continuously variable transmission includes a primary sheave, a secondary sheave, and a belt wound around both sheaves. The primary sheave is driven by power transmission from the engine and has a pair of clamping surfaces facing each other and a belt groove formed between the clamping surfaces. The secondary sheave drives the rear wheels of the motorcycle via a power transmission mechanism or a speed reduction mechanism. The secondary sheave includes a pair of clamping surfaces facing each other and a belt groove formed between the clamping surfaces.

  The belt is wound endlessly between the belt groove of the primary sheave and the belt groove of the secondary sheave. This belt has a sandwiched surface that contacts the belt sandwiching surface of each sheave. The rotational force of the primary sheave is transmitted to the secondary sheave through the belt by the frictional force generated between the sandwiched surface of the belt and the sandwiching surface of each sheave.

  As shown in FIG. 7, this type of belt-type continuously variable transmission has a characteristic that the torque that can be transmitted between the sheave and the belt increases as the thrust of each sheave sandwiching the belt increases. have. When the thrust applied to the belt increases, a large frictional resistance is generated between the holding surface of the sheave and the clamped surface of the belt, and the heat generation amount of the belt increases. The heat generation of the belt indicates that the kinetic energy is changed to the thermal energy, and the torque transmission efficiency is lowered accordingly.

FIG. 8 shows changes in the heat generation amount and transmission efficiency of the belt when the thrust applied to the belt is changed. As is apparent from FIG. 8, when the thrust increases, the heat generation amount of the belt increases in proportion to the thrust, and the torque transmission efficiency decreases. Therefore, in order to increase the torque transmission efficiency between the sheave and the belt, it is necessary to set the thrust to the minimum necessary.
JP 2002-147553 A

  By the way, according to the conventional belt-type continuously variable transmission, when the operation is started with the sheave and belt after completion of assembly being new, the belt tends to slip, particularly at the initial stage of the operation. FIG. 9 shows the transition of the belt transmission torque at the beginning of operation. As is apparent from FIG. 9, immediately after the operation is started, the torque transmitted to the belt is significantly lower than the predetermined set value c. This torque value tends to gradually increase with the lapse of the operation time, and reaches the set value when a certain time has passed.

  As a means for suppressing belt slip in the initial stage of operation, it is conceivable to increase the thrust applied to the belt. However, when the thrust is increased, it is inevitable that the amount of heat generated by the belt increases as described above. Therefore, after the break-in operation is completed, the thrust applied to the belt becomes excessive, resulting in a problem that the torque transmission efficiency is deteriorated.

  An object of the present invention is to provide a belt type continuously variable transmission that can prevent the belt from slipping while minimizing the thrust applied to the belt.

  Another object of the present invention is to provide a belt-type continuously variable transmission sheave that can prevent the belt from slipping while minimizing the thrust applied to the belt.

  Still another object of the present invention is to provide a vehicle equipped with a belt-type continuously variable transmission capable of preventing belt slipping while minimizing the thrust applied to the belt.

  According to the first, fourth, and seventh aspects of the invention, a belt-type continuously variable transmission that transmits the rotational force of the primary sheave to the secondary sheave via an endless belt, the sheave for the continuously variable transmission, and the continuously variable transmission In the vehicle equipped with the apparatus, at least one belt clamping surface of the primary sheave or the secondary sheave is configured to be plastically deformed by contact with the belt so that the surface roughness is smooth.

  The inventions of claims 2, 5 and 8 are characterized in that a plating film is formed on the belt holding surface of the sheave, and the plating film is plastically deformed by contact with the belt.

  The inventions of claims 3, 6 and 9 are characterized in that the belt holding surface of the sheave is provided with unevenness for peeling off the extreme surface of the belt holding surface.

  According to the first, fourth, and seventh aspects of the present invention, at least one belt clamping surface of the primary side sheave or the secondary side sheave is plastically deformed by contact with the belt and the surface roughness becomes smooth. The contact state between the surface and the clamped surface of the belt is easily stabilized, and initial slip can be suppressed.

  According to the inventions of claims 2, 5 and 8, since the plating film formed on the belt clamping surface of the sheave is plastically deformed by contact with the belt, the sheave-side belt clamping surface and the belt-side clamping surface The contact state is further stabilized, and initial slip can be suppressed.

  Furthermore, according to the inventions of claims 3, 6 and 9, since the unevenness that peels off the pole surface of the sandwiched surface of the belt is formed on the belt sandwiching surface of the sheave, the sheave between the sheave and the belt at the start of operation is formed. As the coefficient of friction increases, so-called skinning that peels off the belt surface can be completed in a short time, and the initial slip can be suppressed from this point.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  1 to 4 are diagrams for explaining a belt-type continuously variable transmission according to an embodiment of the present invention, FIG. 1 is a sectional plan view thereof, and FIG. 2 is a diagram for explaining a state of a holding surface of a sheave. FIG. 3 is a schematic enlarged view for explaining the state of the sandwiching surface of the sheave. FIG. 4 is a diagram showing the results of measuring the surface roughness of the sandwiching surface of the sheave.

  In FIG. 1, reference numeral 1 denotes a belt type continuously variable transmission employed in a motorcycle, which is disposed on a side of a crankcase of an engine (not shown). The continuously variable transmission 1 has a primary sheave 3 attached to an input shaft 2 to which engine torque is transmitted, and a secondary sheave 5 attached to an output shaft 4 arranged in parallel with the input shaft 2. The V-belt 6 is wound around the secondary sheave 5 and the primary sheave 3. The rotation of the output shaft 4 is transmitted to the rear wheel shaft via a power transmission mechanism (not shown).

  The primary sheave 3 is moved in the axial direction inside the primary sheave half 3a fixed to the outer end of the input shaft 2 so as to rotate together with the primary sheave half 3a of the input shaft 2. And a primary movable sheave half 3b mounted so as to rotate together with the input shaft 2 via a slide collar 7.

  A cam plate 8 is mounted inside the movable sheave half 3b of the input shaft 2, and the cam plate 8 is fixed to the input shaft 2 so as to rotate together. A weight 9 is arranged between the cam plate 8 and the movable sheave half 3b so as to be movable radially outward by centrifugal force.

  The secondary sheave 5 is attached to a secondary side fixed sheave half 5a fixed to the output shaft 4 and to be movable in the axial direction outside the fixed sheave half 5a and to rotate with the fixed sheave half 5a. Secondary-side movable sheave half 5b.

  A cylindrical slide collar 10 is fixed to the shaft core of the fixed sheave half 5a, and the slide collar 10 is fixed to the output shaft 4 so as to rotate together. A cylindrical portion 5c fixed to the shaft core portion of the secondary movable sheave half 5b is mounted on the slide collar 10 so as to be movable in the axial direction.

  Engaging grooves 5d extending in the axial direction are formed in the cylindrical portion 5c of the movable sheave half 5b at predetermined intervals in the circumferential direction. Engagement pins 11 are inserted into the respective engagement grooves 5 d, and the engagement pins 11 are fastened and fixed to the slide collar 10. In this way, the movable sheave half 5b is movable in the axial direction and rotates together with the fixed sheave half 5a.

  A spring receiving member 12 is fixed to the outer end portion of the slide collar 10, and the movable sheave half 5b is placed between the spring receiving member 12 and the movable sheave half 5b on the fixed sheave half 5a side. A spring 13 for biasing is interposed.

  Each sheave half 3a, 3b, 5a, 5b has a V-belt clamping surface 15 formed so as to form a conical surface, and each of the primary and secondary fixed sheave halves 3a, 5a and the movable sheave half. A V-shaped groove is formed in each of 3b and 5b, and a V-belt 6 is fitted in the groove. The V-belt 6 is sandwiched between the sheave halves 3a, 3b and 5a, 5b with a predetermined sheave thrust.

  In the state where the engine speed is the lowest, the weight 9 is positioned radially inward, the primary movable sheave half 3b moves axially inward and away from the fixed sheave half 3a, and the sheave winding diameter decreases, The secondary movable sheave half 5b is urged by the spring 13 and moves to the fixed sheave half 5a side, the sheave winding diameter increases, and the low reduction position of the maximum reduction ratio is obtained.

  When the rotational speed of the input shaft 2 increases as the engine speed increases, the weight 9 moves radially outward due to the centrifugal force to move the primary movable sheave half 3b toward the fixed sheave half 3a. As the sheave winding diameter increases, the secondary movable sheave half 5b moves outward in the axial direction against the urging force of the spring 13, and the sheave winding diameter is minimized at the highest engine speed. It is the top position of the minimum reduction ratio.

  The V-belt 6 is made of a resin having heat resistance and durability. For example, a large number of resin blocks 6 a formed by mixing carbon fibers or aramid fibers into a polyamide resin and having a substantially horizontal H shape are arranged in a row. The resin blocks 6a are arranged to be connected by an annular connecting band 6b made of super heat resistant rubber or metal.

  The primary side sheave 3 and the secondary side sheave 5 employ the configuration that characterizes this embodiment. The fixed sheave halves 3a and 5a and the movable sheave halves 3b and 5b constituting the respective sheaves 3 and 5 are manufactured using an aluminum alloy, for example, AC4B or ADC-11. The sandwiching surface 15 of each of the sheave halves 3a, 3b, 5a, 5b has a structure in which a plating film 16 is formed on the metal surface 15a made of the aluminum alloy.

  As the plating film 16, NI-P plating having a surface hardness of 600 to 1000 Hv and a Vickers crack generation load (toughness) of 250 to 350 N, for example, “KENI COAT (registered trademark)” of Kobe Steel, Ltd. can be employed.

  Here, each of the sheaves 3 and 5 is formed into a semi-finished product by forging or casting, and adopted as a final product by performing machining such as cutting and grinding on the metal surface 15a constituting the clamping surface 15. Is possible. Such machining is performed by cutting a blade or a grindstone into the surface while rotating the half of the sheave around the rotation axis. If it sees specifically, the process trace 15b which makes an annular groove | channel will be formed in the said metal surface 15a (refer FIG. 2).

  The machining mark 15b has irregularities composed of a groove part and a peak part. The groove depth or peak height and groove width of the uneven part is approximately several times when the continuously variable transmission 1 is unused. μm to several tens of μm. The plating film 16 has a film thickness of about several μm to 10 μm and is formed along the surface shape forming the irregularities of the processing mark 15b. Therefore, the surface of the plating film 16 is also formed on the processing mark 15b. Corresponding irregularities are formed (see FIG. 3A).

  When traveling is started by a motorcycle equipped with the continuously variable transmission 1 of the present embodiment, the plating film 16 and the metal surface 15a of the clamping surface 15 are struck by the V belt 6, and after a certain amount of traveling, the above processing is performed. The irregularities forming the trace are plastically deformed, the depth of the processed trace 15a becomes shallower, the width of the groove becomes narrower, and the whole becomes flat (see FIG. 3B). As apparent from FIG. 3B, the metal surface 15a is hardly exposed due to wear or peeling of the plating film 16 even if the above-described plastic deformation proceeds.

  Here, FIG. 4A shows the result of measuring the sandwiching surface 15 of each sheave with a surface roughness meter in the non-running state, and FIG. 4B shows the measurement result after running. In FIGS. 4A and 4B, the vertical axis is displayed 50 times larger than the horizontal axis. That is, the horizontal axis representing the radial position of the clamping surface has a unit scale of 100 μm, whereas the vertical axis representing the surface roughness has a unit scale of 2 μm.

  In the above non-running state, the surface roughness is about 3 μm as shown in FIG. 4A, whereas in the state after running, the surface roughness is about 3 μm as shown in FIG. It is 2 μm or less. Further, from FIG. 5B, it can be seen that the unevenness of the clamping surface is plastically deformed and the surface is smooth.

  As described above, the clamping surface 15 formed of the metal surface 15a and the plating film 16 of the present embodiment is plastically deformed by being struck by the V-belt 6, and the surface state becomes smooth, and the clamping surface on the sheave side and the belt As a result, the initial slip can be suppressed without increasing the thrust of the sheave.

  Further, in this embodiment, the surface of the clamping surface 15 becomes smooth by plastic deformation, and the plating film 16 and the metal surface 15a are hardly scraped. The contact state with the clamping surface can be stabilized over a long period of time, and belt slippage can be suppressed over a long period of time without increasing the sheave thrust.

  In the very initial stage of the operation, the friction coefficient between the belt and the clamped surface of the belt increases due to the unevenness of the processing marks 15a formed on the clamping surface 15. From this point, the belt of the belt at the start of the operation starts. Initial slip can be suppressed. Furthermore, the so-called peeling of the pole surface of the V-belt 6 by the unevenness is performed in a short time, and this point is considered to contribute to the suppression of the initial slip.

  Further, when the vehicle travels to some extent as described above, the unevenness of the clamping surface is plastically deformed and the surface becomes smooth, so that wear of the V belt 6 thereafter can be suppressed.

  In the above embodiment, as schematically illustrated in FIG. 3, the case where the plating film 16 is formed thicker than the groove depth of the processing mark 15 a has been described. However, various modifications may be made to the plating film and the groove depth. For example, as shown in FIGS. 5 and 6, the plating film 16 may be formed thinner than the groove depth.

  In the above embodiment, the case where the plating film is formed on the metal surface has been described. However, the material and surface treatment of the sandwiching surface of the sheave may be determined in accordance with the material and surface state of the sandwiched surface of the belt. It is also possible not to form a film.

  Of course, the material of the sheave is not limited to the above-described embodiment. In the present invention, the surface of the sandwiching surface of the sheave is plastically deformed by contact with the belt at the beginning of running. What is necessary is just to comprise so that it may become smooth.

1 is a cross-sectional plan view of a belt type continuously variable transmission according to an embodiment of the present invention. It is a schematic diagram for demonstrating the surface state of the sheave of the said embodiment. It is a schematic cross-sectional enlarged view for demonstrating the said surface state. It is a figure which shows the measurement result by the surface roughness meter of the said surface state. It is a schematic cross-sectional enlarged view which shows the modification of the said surface state. It is a schematic cross-sectional enlarged view which shows the other modification of the said surface state. FIG. 5 is a characteristic diagram showing a relationship between sheave thrust and transmission torque in a general belt type continuously variable transmission. It is a characteristic view which shows the relationship between the sheave thrust in a general belt type continuously variable transmission, a heat generating material, and transmission efficiency. It is a characteristic view which shows the relationship between the driving time and the transmission torque in a general belt type continuously variable transmission.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Belt type continuously variable transmission 3 Primary side sheave 5 Secondary side sheave 6 V belt 15 Belt clamping surface 15b Processing trace (unevenness)
16 Plating film

Claims (9)

  In the belt-type continuously variable transmission that transmits the rotational force of the primary sheave to the secondary sheave through an endless belt, at least one belt clamping surface of the primary sheave or the secondary sheave is brought into contact with the belt. A belt-type continuously variable transmission configured to be plastically deformed to have a smooth surface roughness.   The belt-type continuously variable transmission according to claim 1, wherein a plating film is formed on a belt holding surface of the sheave, and the plating film is plastically deformed by contact with the belt.   3. The belt type continuously variable transmission according to claim 1, wherein the belt holding surface of the sheave is provided with irregularities for peeling off the pole surface of the holding surface of the belt.   In a belt-type continuously variable transmission sheave that transmits the rotational force of the primary sheave to the secondary sheave through an endless belt, the belt clamping surface of the sheave is plastically deformed by contact with the belt, resulting in surface roughness. A belt-type continuously variable transmission sheave characterized in that the belt is smooth.   5. The sheave for a belt type continuously variable transmission according to claim 4, wherein a plating film is formed on a belt holding surface of the sheave, and the plating film is plastically deformed by contact with the belt.   6. The sheave for a belt-type continuously variable transmission according to claim 4, wherein the belt-clamping surface of the sheave is provided with irregularities that peel off the pole surface of the clamped surface of the belt.   In a vehicle equipped with a belt-type continuously variable transmission that transmits the rotational force of the primary sheave to the secondary sheave through an endless belt, the belt clamping surface of at least one of the primary sheave or the secondary sheave A vehicle equipped with a belt-type continuously variable transmission, which is configured to be plastically deformed by contact with the belt and to have a smooth surface roughness.   8. A vehicle equipped with a belt type continuously variable transmission according to claim 7, wherein a plating film is formed on a belt holding surface of the sheave, and the plating film is plastically deformed by contact with the belt.   6. A vehicle equipped with a belt-type continuously variable transmission according to claim 4 or 5, wherein the belt holding surface of the sheave is provided with unevenness for peeling off the pole surface of the holding surface of the belt.

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