Pulley and belt-type continuously variable transmission

Abstract

The drive pulley (110) is provided with: a fixed pulley (111) having a fixed pulley surface (111S) that is in contact with the V-belt (130); a fixed boss (116) which extends rightward from the fixed pulley (111) and is formed in a cylindrical shape; a movable pulley (112) that has a movable pulley surface (112S) that is in contact with the V-belt (130) and that is disposed at a position facing the fixed pulley surface (111S), and that can approach and move away from the fixed pulley (111); and a cylindrical movable boss (117) which protrudes from the movable pulley (112) to the right, is fitted over the fixed boss (116), and slides along the outer peripheral surface (116B) of the fixed boss (116), the crankshaft (68) is inserted into the fixed boss (116), and an oxide film is formed on the inner peripheral surface (116A) of the fixed boss (116).

Description

Technical Field

[0001] The present invention relates to a pulley used in a belt-type continuously variable transmission and a belt-type continuously variable transmission including the pulley. Background Art

[0002] As a transmission used in vehicles such as motorcycles, a belt-type continuously variable transmission has long been known. The belt-type continuously variable transmission includes a driving pulley, a driven pulley, and a V-belt (driving belt) wound around the driving pulley and the driven pulley. The driving pulley and the driven pulley each include a fixed pulley and a movable pulley that can move closer to and farther from the fixed pulley. For example, Patent Document 1 discloses a V-belt continuously variable transmission, which includes: a driving pulley disposed on a crankshaft; a driven pulley (equivalent to a driven pulley) disposed on a driven shaft; and a V-belt wound around the driving pulley and the driven pulley.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2010-236647 Summary of the invention

[0006] Problems to be solved by the invention

[0007] In addition, the driving pulley and the driven pulley are provided with: a fixed pulley having a fixed pulley surface for the driving belt to contact; a cylindrical fixed boss; and a movable pulley having a movable pulley surface for the driving belt to contact, and sliding on the outer diameter side of the fixed boss, and being able to approach and move away from the fixed pulley. The fixed boss of the driving pulley is arranged in contact with the fixed pulley. In addition, the fixed boss of the driven pulley is formed integrally with the fixed pulley and protrudes from the fixed pulley. Here, since the movable pulley moves axially on the outer periphery of the fixed boss of the driving pulley and the driven pulley, the strength and wear resistance of the fixed boss to sliding are improved by, for example, performing hard chrome plating after high-frequency quenching. However, due to the nature of hard chrome plating and high-frequency quenching, it is difficult to harden the inner peripheral surface of the fixed boss, and there is a problem that the wear resistance of the inner peripheral surface of the fixed boss is low.

[0008] The present invention has been made in view of the above-mentioned point, and an object of the present invention is to provide a pulley having an improved wear resistance of an inner peripheral surface of a fixed boss and a belt-type continuously variable transmission including the pulley.

[0009] Means for solving problems

[0010] The pulley of the present invention is used for a belt-type continuously variable transmission, wherein the pulley comprises: a fixed pulley having a fixed pulley surface in contact with a drive belt; a fixed boss extending from the fixed pulley in a first direction and formed in a cylindrical shape; a movable pulley having a movable pulley surface in contact with the drive belt and arranged at a position facing the fixed pulley surface and capable of approaching and moving away from the fixed pulley; and a movable boss extending from the movable pulley in the first direction and formed in a cylindrical shape, and being externally fitted on the fixed boss and sliding along the outer peripheral surface of the fixed boss, a shaft being inserted into the fixed boss, and an oxide film being formed on the inner peripheral surface of the fixed boss.

[0011] According to the pulley of the present invention, an oxide film is formed on the inner peripheral surface of the fixed boss into which the shaft is inserted. Therefore, the sliding property and wear resistance of the inner peripheral surface of the fixed boss are relatively high. Thus, even if a force is applied to the shaft, for example, so that the inner peripheral surface of the fixed boss rubs against the shaft, the wear of the inner peripheral surface of the fixed boss can be suppressed.

[0012] Effects of the Invention

[0013] According to the present invention, it is possible to provide a pulley having an improved wear resistance of the inner peripheral surface of the fixing boss. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a side view of the motorcycle according to one embodiment.

[0015] Figure 2 This is a cross-sectional view of an engine unit according to an embodiment.

[0016] Figure 3 This is a cross-sectional view of a drive pulley according to one embodiment.

[0017] Figure 4 This is a cross-sectional view of a driven pulley according to one embodiment.

[0018] Figure 5 It is a cross-sectional view showing the structure around the torque cam groove of the driven pulley according to one embodiment.

[0019] Figure 6 It is a top view of the driven pulley at low speed according to one embodiment.

[0020] Figure 7 This is a top view of a driven pulley at high speed according to an embodiment. DETAILED DESCRIPTION

[0021] Hereinafter, embodiments of the pulley and the belt-type continuously variable transmission equipped with the pulley of the present invention will be described with reference to the accompanying drawings. Here, a so-called scooter-type motorized two-wheeled vehicle equipped with a belt-type continuously variable transmission is used as an example for description, but the motorized two-wheeled vehicle of the present invention is not limited to the so-called scooter-type motorized two-wheeled vehicle. In addition, the embodiments described here are of course not intended to specifically limit the present invention. In addition, the same reference numerals are given to components and parts that play the same role, and repeated descriptions are appropriately omitted or simplified.

[0022] Figure 1 1 is a side view of the motorcycle 10. In the following description, unless otherwise specified, the front, rear, left, right, top, and bottom refer to the front, rear, left, right, top, and bottom as viewed from the driver of the motorcycle 10. The reference numerals F, Rr, L, R, U, and D in the drawings represent the front, rear, left, right, top, and bottom, respectively.

[0023] like Figure 1 As shown, the motorcycle 10 includes an engine unit 50 .

[0024] like Figure 2 As shown, the engine unit 50 includes: an engine 60; a crankcase 61 that accommodates a crankshaft 68 to be described later; a belt-type continuously variable transmission 100 (hereinafter referred to as CVT100); and a transmission case 70 that accommodates the CVT100. In the present embodiment, the engine 60 and the CVT100 are integrated to form the engine unit 50, but the engine 60 and the CVT100 may also be provided separately.

[0025] like Figure 2 As shown, the engine 60 is a single cylinder engine having a single cylinder. The engine 60 includes a cylinder block 62 extending forward from a crankcase 61 and coupled to the crankcase 61, a cylinder head 63 connected to the front of the cylinder block 62, and a cylinder head cover 64 connected to the front of the cylinder head 63. A cylinder 65 is formed inside the cylinder block 62.

[0026] like Figure 2 As shown in FIG. 1 , a piston 66 is slidably accommodated in a cylinder 65. The piston 66 is connected to a crankshaft 68 via a connecting rod 67. The crankshaft 68 extends to the left and right and is supported by a crankcase 61. The driving force of the crankshaft 68 is transmitted to the rear wheel 44 (see FIG. 1 ) via the CVT 100. Figure 1 ) transmission. The crankshaft 68 is an example of a shaft.

[0027] In the present embodiment, the crankcase 61, the cylinder block 62, the cylinder head 63 and the cylinder head cover 64 are separate and mutually assembled. However, they do not need to be separate and may be appropriately integrated. For example, the crankcase 61 and the cylinder block 62 may be formed integrally, and the cylinder block 62 and the cylinder head 63 may also be formed integrally. In addition, the cylinder head 63 and the cylinder head cover 64 may also be formed integrally.

[0028] There is no limitation on the specific structure of the crankshaft housing 61. Here, the crankshaft housing 61 is composed of a plurality of components. However, the crankshaft housing 61 may also be composed of a single component. Here, the housing for accommodating the crankshaft 68 and the housing for accommodating the CVT 100 are respectively referred to as the crankshaft housing 61 and the transmission housing 70. The crankshaft housing 61 and the transmission housing 70 do not necessarily have to be independent components, and one component may constitute a part or all of the crankshaft housing 61 and the transmission housing 70. For example, a part of the component constituting the crankshaft housing 61 may also constitute a part of the transmission housing 70.

[0029] like Figure 2 As shown, the CVT 100 includes a drive pulley 110 as a drive-side pulley, a driven pulley 120 as a driven-side pulley, and a V-belt 130 wound around the drive pulley 110 and the driven pulley 120. The V-belt 130 is an example of a drive belt.

[0030] like Figure 2 As shown, the driving pulley 110 includes a fixed pulley 111, a movable pulley 112, a fixed boss 116 disposed in contact with the fixed pulley 111, and a movable boss 117 extending from the movable pulley 112 toward the right. In the driving pulley 110 of the present embodiment, the right is an example of the first direction. The fixed pulley 111 and the movable pulley 112 are mounted on the left end of the crankshaft 68, and the driving pulley 110 rotates together with the crankshaft 68. The fixed pulley 111 is located to the left, that is, outside, of the movable pulley 112. The fixed pulley 111 cannot move in the axial direction of the crankshaft 68. The movable pulley 112 can move in the axial direction of the crankshaft 68. The movable pulley 112 is configured to be able to approach and move away from the fixed pulley 111. The fixed pulley 111 and the movable pulley 112 form a V-shaped belt groove for supporting the V-belt 130.

[0031] like Figure 3As shown, the fixed pulley 111 is formed in a disc shape. The fixed pulley 111 has a fixed pulley surface 111S that contacts the V-belt 130. The fixed pulley surface 111S is inclined outward (here, leftward) as it goes from the radial inner side to the radial outer side. The fixed boss 116 extends toward the right from the fixed pulley 111. The fixed boss 116 is arranged at the central part of the fixed pulley 111. The fixed boss 116 is arranged on the surface 111F of the fixed pulley 111 on which the fixed pulley surface 111S is formed. The fixed boss 116 protrudes toward the right from the surface 111F. The fixed boss 116 is formed in a cylindrical shape. The fixed boss 116 is formed of, for example, carbon steel. The crankshaft 68 is inserted into the fixed boss 116. An oxide film is formed on the inner peripheral surface 116A of the fixed boss 116. Therefore, for example, fretting wear that may occur between the crankshaft 68 and the inner peripheral surface 116A of the fixed boss 116 can be suppressed, and rattling and seizure of the crankshaft 68 can be suppressed. In addition, an oxide film is formed on the outer peripheral surface 116B of the fixed boss 116 .

[0032] The oxide film formed on the inner circumferential surface 116A and the outer circumferential surface 116B of the fixed boss 116 includes, for example, an oxide derived from the metal constituting the fixed boss 116. The oxide film includes, for example, ferrosoferric oxide (Fe3O4). The oxide film is formed, for example, by performing a steam treatment after performing a gas soft nitriding treatment (Gas Soft Nitridization). The maximum height Rz of the surface formed with the oxide film is, for example, 1 μm to 12.5 μm (for example, 1 μm to 3.2 μm). The maximum height Rz is a value measured based on JISB0601:2013. In addition, there may be compounds derived from the gas soft nitriding treatment (for example, Fe3N, Fe4N) between the inner circumferential surface 116A and the outer circumferential surface 116B of the fixed boss 116 and the oxide film.

[0033] like Figure 3 As shown, the movable pulley 112 is formed in a disc shape. The movable pulley 112 has a movable pulley surface 112S that contacts the V-belt 130. The movable pulley surface 112S is inclined outward (rightward in this case) as it goes from the radial inner side to the radial outer side. The movable pulley surface 112S is arranged at a position opposite to the fixed pulley surface 111S. The V-belt 130 is sandwiched between the movable pulley surface 112S and the fixed pulley surface 111S. The movable boss 117 is connected to the movable pulley 112. The movable boss 117 is formed integrally with the movable pulley 112. The movable boss 117 is provided at the center portion of the movable pulley 112. The movable boss 117 is arranged on the back side 112R of the movable pulley 112 located on the opposite side (right side in this case) of the movable pulley surface 112S. The movable boss 117 protrudes rightward from the back surface 112R. The movable boss 117 is formed in a cylindrical shape. The movable boss 117 is externally fitted to the fixed boss 116 and slides along the outer peripheral surface 116B of the fixed boss 116.

[0034] like Figure 2 As shown, the driven pulley 120 has a fixed pulley 121, a movable pulley 122, a fixed boss 126 protruding from the fixed pulley 121 toward the left, and a movable boss 127 protruding from the movable pulley 122 toward the left. In the driven pulley 120 of this embodiment, the left is an example of the first direction. The fixed pulley 121 and the movable pulley 122 are mounted on the main shaft 72, and the driven pulley 120 rotates together with the main shaft 72 after the engagement of the centrifugal clutch 150. The fixed pulley 121 is located to the right, that is, inward, of the movable pulley 122. The fixed pulley 121 cannot move in the axial direction of the main shaft 72. The movable pulley 122 can move in the axial direction of the main shaft 72 along the outer periphery of the fixed boss 126. The movable pulley 122 is configured to be able to approach and move away from the fixed pulley 121. The fixed pulley 121 and the movable pulley 122 form a V-shaped belt groove that supports the V-belt 130. The main shaft 72 is connected to a rear wheel axle 76 that rotatably supports the rear wheel via a gear mechanism 74.

[0035] like Figure 4 As shown, the fixed pulley 121 is formed in a disc shape. The fixed pulley 121 has a fixed pulley surface 121S that contacts the V-belt 130. The fixed pulley surface 121S is inclined outward (here, rightward) as it goes from the radial inner side to the radial outer side. The fixed boss 126 is connected to the fixed pulley 121. The fixed boss 126 is fixed to the fixed pulley 121 by welding, for example. The fixed boss 126 is provided in the center portion of the fixed pulley 121. The fixed boss 126 is arranged on a surface 121F of the fixed pulley 121 on which the fixed pulley surface 121S is formed. The fixed boss 126 protrudes toward the left from the surface 121F. The fixed boss 126 is formed in a cylindrical shape. The main shaft 72 is inserted into the fixed boss 126. Here, the main shaft 72 is an example of a shaft. An oxide film is formed on the inner peripheral surface 126A of the fixed boss 126. An oxide film is formed on outer peripheral surface 126B of fixing boss 126. The oxide film formed is the same as the oxide film formed on inner peripheral surface 116A of fixing boss 116 and the like.

[0036] like Figure 5 As shown in FIG. 1 , the driven pulley 120 includes a torque cam groove 118 penetrating through a movable boss 127, a guide pin 128 inserted into the torque cam groove 118, and a pin hole 129 formed in the fixed boss 126. The guide pin 128 is inserted into the torque cam groove 118. The torque cam groove 118 guides the movement of the movable pulley 122. The torque cam groove 118 generates a thrust force that clamps the V-belt 130, and transmits the driving force from the V-belt 130 to the rear wheel shaft 76. Figure 6As shown, the torque cam groove 118 extends along the circumferential direction of the movable boss 127. The torque cam groove 118 is formed in a substantially oblong shape. The movable pulley 122 can move relative to the fixed pulley 121 along the torque cam groove 118 in the axial direction of the main shaft 72. The movable pulley 122 can rotate relative to the fixed pulley 121 along the torque cam groove 118.

[0037] like Figure 5 As shown, a guide roller 128G is mounted on the guide pin 128. The guide roller 128G is provided to be rotatable around the guide pin 128. The guide roller 128G is a member for smoothly moving the guide pin 128 along the torque cam groove 118. The guide roller 128G is a member for suppressing positional deviation between the guide pin 128 and the torque cam groove 118. The pin hole 129 penetrates the fixed boss 126 in the radial direction. The guide pin 128 is inserted into the pin hole 129. The guide pin 128 is fixed to the pin hole 129. The guide pin 128 is fixed to the inner peripheral surface 126C of the fixed boss 126 that divides the pin hole 129. The inner peripheral surface 126C of the fixed boss 126 that divides the pin hole 129 is formed with an oxide film similar to the oxide film formed on the inner peripheral surface 116A of the fixed boss 116. The oxide film can be formed over the entire inner peripheral surface 126C. The inner peripheral surface 126C is an example of another inner peripheral surface. The inner peripheral surface 126C is connected to the inner peripheral surface 126A and the outer peripheral surface 126B. The inner peripheral surface 126C is a surface extending in the radial direction of the fixing boss 116.

[0038] like Figure 4As shown, the movable pulley 122 is formed in a disc shape. The movable pulley 122 has a movable pulley surface 122S that contacts the V-belt 130. The movable pulley surface 122S is inclined outward (here, leftward) as it goes from the radial inner side to the radial outer side. The movable pulley surface 122S is arranged at a position opposite to the fixed pulley surface 121S. The V-belt 130 is sandwiched between the movable pulley surface 122S and the fixed pulley surface 121S. The movable boss 127 is connected to the movable pulley 122. The movable boss 127 is fixed to the movable pulley 122 by welding, for example. The movable boss 127 is provided at the center portion of the movable pulley 122. The movable boss 127 is fixed to the inner peripheral surface of the through hole portion of the movable pulley 122 by welding or the like. The movable boss 127 protrudes toward the left from the movable pulley 122. The movable boss 127 is formed in a cylindrical shape. The movable boss 127 is externally fitted to the fixed boss 126 and slides along the outer peripheral surface 126B of the fixed boss 126. An oxide film similar to the oxide film formed on the inner peripheral surface 116A of the fixed boss 116 is formed on the inner peripheral surface 127A of the movable boss 127. In addition, the fixed pulley 121 and the movable pulley 122 are provided with a guide pin 128 and a guide roller 128G in the pin hole 129 formed in the fixed boss 126 of the fixed pulley 121 and the torque cam groove 118 formed in the movable boss 127 of the movable pulley 122 to determine the phase difference between the two.

[0039] like Figure 6 As shown in FIG. 1 , when the motorcycle 10 is running at a low speed, for example, the movable pulley 122 is closest to the fixed pulley 121. At this time, the guide pin 128 is located at the leftmost position of the torque cam groove 118. Then, by moving the movable pulley 122 to the left along the torque cam groove 118, the reduction ratio of the CVT 100 is changed. Figure 7 As shown, when the motorcycle 10 is running at a high speed, for example, the movable pulley 122 is farthest from the fixed pulley 121. At this time, the guide pin 128 is located at the rightmost position of the torque cam groove 118. And, by moving the movable pulley 122 to the right along the torque cam groove 118, the reduction ratio of the CVT 100 is changed. In addition, when the movable pulley 122 moves along the torque cam groove 118 in the axial direction of the main shaft 72, an external force is applied to the inner peripheral surface 126C that defines the pin hole 129 into which the guide pin 128 is inserted, so that the inner peripheral surface 126C is easily worn. However, as described above, an oxide film is formed on the inner peripheral surface 126C, so the wear resistance is high, and the wear of the inner peripheral surface 126C can be suppressed. As a result, the guide pin 128 is suppressed from tilting relative to the pin hole 129.

[0040] like Figure 2As shown, the transmission case 70 is arranged on the left side of the crankshaft case 61. The transmission case 70 includes a case body 80 fixed to the crankshaft case 61 and a cover 82 fixed to the case body 80 in a detachable manner. The case body 80 accommodates the CVT 100. That is, the case body 80 accommodates the driving pulley 110, the driven pulley 120 and the V-belt 130. An opening 81 is formed on the left side of the driving pulley 110 in the case body 80. The cover 82 covers the opening 81 of the case body 80.

[0041] As described above, according to the drive pulley 110 of the present embodiment, an oxide film is formed on the inner peripheral surface 116A of the fixed boss 116 into which the crankshaft 68 is inserted. Therefore, the sliding property and wear resistance of the inner peripheral surface 116A of the fixed boss 116 are relatively high. Thus, even if a force is applied to the crankshaft 68, for example, so that the inner peripheral surface 116A of the fixed boss 116 and the crankshaft 68 rub against each other, the wear of the inner peripheral surface 116A of the fixed boss 116 can be suppressed.

[0042] The driven pulley 120 of this embodiment includes a torque cam groove 118 formed through the movable boss 127 and guiding the movement of the movable pulley 122, a guide pin 128 inserted into the torque cam groove 118, and a pin hole 129 formed in the fixed boss 126 and fixed with the guide pin 128, and an oxide film is formed on the inner peripheral surface 126C of the fixed boss 126 that defines the pin hole 129. According to the above, when the movable pulley 122 moves along the torque cam groove 118, the external force from the movable pulley 122 is applied to the guide pin 128 inserted into the torque cam groove 118, so that the inner peripheral surface 126C of the fixed boss 126 that defines the pin hole 129 and the guide pin 128 rub against each other. Here, since the oxide film is formed on the inner peripheral surface 126C, the sliding property and wear resistance of the inner peripheral surface 126C are relatively high, so the wear of the inner peripheral surface 126C can be suppressed.

[0043] In the driven pulley 120 of the present embodiment, an oxide film is formed on the outer peripheral surface 126B of the fixed boss 126. According to the above aspect, the slidability and wear resistance of the outer peripheral surface 126B of the fixed boss 126 become relatively high due to the presence of the oxide film. As a result, when the movable pulley 122 slides relative to the fixed pulley 121, the wear of the outer peripheral surface 126B of the fixed boss 126 can be suppressed.

[0044] In the driven pulley 120 of the present embodiment, an oxide film is formed on the inner peripheral surface 127A of the movable boss 127. According to the above aspect, the slidability and wear resistance of the inner peripheral surface 127A of the movable boss 127 become relatively high due to the presence of the oxide film. As a result, when the movable pulley 122 slides relative to the fixed pulley 121, the wear of the outer peripheral surface 126B of the fixed boss 126 and the inner peripheral surface 127A of the movable boss 127 can be suppressed.

[0045] In the driving pulley 110 and the driven pulley 120 of the present embodiment, the oxide film includes ferrosoferric oxide (Fe 3 O 4 ). The oxide film including ferrosoferric oxide has excellent wear resistance and sliding properties and can be formed at a relatively low cost, so that cost reduction can be achieved.

[0046] The preferred embodiments of the present invention have been described above, but the above embodiments are merely examples, and the present invention can be implemented in various other forms.

[0047] In the above embodiment, an oxide film is formed on the inner peripheral surface 116A of the fixing boss 116, but the present invention is not limited thereto. Instead of forming an oxide film, the inner peripheral surface 116A of the fixing boss 116 may be subjected to a known surface treatment to improve the wear resistance and sliding property of the inner peripheral surface 116A.

[0048] In the above-described embodiment, the guide roller 128G is attached to the guide pin 128 , but the guide roller 128G may not be attached to the guide pin 128 . In this case, the guide pin 128 inserted into the torque cam groove 118 directly slides on the movable boss 127 .

[0049] Description of symbols

[0050] 10 Motorcycles

[0051] 68 Crankshaft

[0052] 72 Spindle

[0053] 100 CVT (belt-type continuously variable transmission)

[0054] 110 Drive pulley

[0055] 111 Fixed pulley

[0056] 111S Fixed pulley surface

[0057] 112 Movable pulley

[0058] 112S Movable pulley surface

[0059] 116 Fixed boss

[0060] 116A Inner Surface

[0061] 116B Outer Surface

[0062] 117 Movable boss

[0063] 118 Torque cam groove

[0064] 120 Driven pulley

[0065] 121 Fixed pulley

[0066] 121S Fixed Pulley Surface

[0067] 122 Movable pulley

[0068] 122S Movable pulley surface

[0069] 126 Fixed boss

[0070] 126A Inner Surface

[0071] 126B Outer surface

[0072] 126C Inner Surface (Other Inner Surfaces)

[0073] 127 Movable boss

[0074] 127A Inner Surface

[0075] 128 Guide pin

[0076] 129 Pin hole

[0077] 130 V-belt (drive belt).

Claims

1. A pulley for a belt-type continuously variable transmission, wherein: The pulley has: a fixed pulley having a fixed pulley surface in contact with the drive belt; A fixed boss extending from the fixed pulley toward the first direction and formed in a cylindrical shape; a movable pulley having a movable pulley surface that contacts the drive belt and is disposed at a position facing the fixed pulley surface, and can approach and move away from the fixed pulley; as well as The movable boss extends from the movable pulley toward the first direction and is formed into a cylindrical shape, and is externally fitted on the fixed boss to slide along the outer peripheral surface of the fixed boss. A shaft is inserted into the fixing boss. An oxide film is formed on the inner peripheral surface of the fixing boss.

2. The pulley according to claim 1, The pulley has: a torque cam groove formed through the movable boss and guiding the movement of the movable pulley; a guide pin inserted into the torque cam groove; and a pin hole formed in the fixing boss and fixed with the guide pin, The oxide film is formed on the other inner peripheral surface of the fixing boss that defines the pin hole.

3. The pulley according to claim 1 or 2, The oxide film is formed on the outer peripheral surface of the fixing boss.

4. The pulley according to claim 3, The oxide film is formed on the inner peripheral surface of the movable boss.

5. The pulley according to claim 1 or 2, The oxide film includes ferrosoferric oxide (Fe 3 O 4 ).

6. A belt-type continuously variable transmission, The belt-type continuously variable transmission comprises: The pulley according to claim 1 or 2; and The driving belt is sandwiched between the fixed pulley surface and the movable pulley surface.

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