JP4590850B2 - Belt / pulley type continuously variable transmission with parallel grooves and multiple annular grooves - Google Patents

Description

  The present invention relates to a belt / pulley type continuously variable transmission, and more particularly to an improvement relating to a coefficient of friction between the belt and a pulley.

As one of the continuously variable transmissions, an endless belt is stretched between a plurality of pulley assemblies each including a pair of pulley halves each having a pair of opposed conical belt receiving surfaces. 2. Description of the Related Art A belt / pulley type continuously variable transmission is known that transmits rotational power in which a speed ratio is variably adjusted between a plurality of pulley assemblies by changing a relative ratio of a belt wrapping radius. The basic structure of such a belt / pulley continuously variable transmission is as illustrated in FIGS. Here, FIG. 7 is an illustrative plan view of the continuously variable transmission, and FIG. 6 is an arrow view of a half side surface of the continuously variable transmission with a virtual cut surface shown as VI-VI in FIG. is there.

  In these drawings, 10a and 10b are a pair of pulley halves constituting one pulley assembly 10, and 12a and 12b are a pair of pulley halves constituting another pulley assembly 12. In this example, one endless belt 14 is stretched between two pulley assemblies. The pulley 10 a is fixed on the shaft 16, and the shaft 16 is rotatably supported via a bearing 20 from the housing 18, which is shown only partially in the drawing at one end thereof. It rotates with it. The shaft 16 is rotatably supported by the housing 18 via a bearing 22 at the other end. A spline 24 is formed on the shaft 16 from the middle portion to the vicinity of the other end portion. A pulley half body 10b having a spline hole engaged therewith is attached to the spline portion, and the pulley half body 10b is attached. Is configured to rotate with the pulley half body 10a while being variably controlled. A grooved flange 26 is provided at one end of the pulley half 10b, and the tip of the mover 30 of the linear actuator 28 is engaged with the annular groove, so that the pulley half is moved by the movement of the mover 30. The distance 10b is variably controlled along the spline portion of the shaft 16 with respect to the pulley half 10a. A gear 32 is provided at one end of the shaft 16.

  Similarly, in the pulley assembly 12, the pulley 12 a is fixed on the shaft 34, and the shaft 34 is rotatably supported at one end by the housing 18 via the bearing 36, and the bearing at the other end. The pulley 12a is rotated together with the shaft 34 by being rotatably supported by the housing 18 via 38. A spline 40 is also formed on the shaft 34 from the middle portion to the vicinity of the other end portion, and a pulley half body 12b having a spline hole engaged therewith is attached to the spline portion, and the pulley half body 12b is attached. Is configured to rotate with the pulley half body 12a while being variably controlled. A grooved flange 42 is provided at one end of the pulley half 12b, and the tip of the mover 46 of the linear actuator 44 is engaged with the annular groove, whereby the pulley half is moved by the movement of the mover 46. The distance 12b is variably controlled along the spline portion of the shaft 34 with respect to the pulley half 12a. A gear 48 is provided at one end of the shaft 34.

  The endless belt 14 is a pair of endless belt sheets 54 in which a number of belt blocks 50 are overlapped as shown in a perspective view of the endless belt 14 and are fitted in a pair of side slits 52 of each belt block. It is connected with. Each belt block 50 comes into contact with the belt receiving surfaces of the pulley halves 10a, 10b and 12a, 12b at both side surfaces 56 thereof. For example, the following Patent Document 1 discloses that a groove 58 is provided on the pulley contact surface of the belt block in parallel with the belt as shown in the drawing to increase the friction coefficient at the contact between the belt and the pulley. As already known.

  In the belt / pulley type continuously variable transmission as described above, radial irregularities are formed on the inner diameter part of the driving pulley and the outer diameter part of the driven pulley for the purpose of preventing initial slippage during acceleration. It is described in Patent Document 2 below to provide a radiation groove as much as possible. In the belt / pulley type continuously variable transmission as described above, Patent Document 3 below describes that the friction coefficient of the pulley with respect to the belt is increased as the diameter of the pulley is smaller. Further, in the belt / pulley type continuously variable transmission as described above, it is disclosed in Patent Document 4 below that a surface treatment for improving the friction coefficient and wear resistance such as shot peening is applied to the pulley surface in a region where the pulley diameter is small. Are listed. Further, in the belt / pulley type continuously variable transmission as described above, one or both of the surfaces where the belt or the pulley contact each other are made discontinuous by unevenness, and the area ratio of the recesses is at least 50%. Is described in Patent Document 5 below. However, the form of the unevenness is unclear except that grooves as shown in Patent Document 1 are provided on both side surfaces of the belt block.

Further, Patent Document 6 below proposes providing radial or concentric ridges on the surface of the pulley for the purpose of increasing the torque transmission capacity of the belt / pulley type continuously variable transmission as described above. . In this case, when the ridges are radial, the outermost peripheral portion of the contact area with the belt is preferably within a range of 0.2 mm or more and 1.3 mm or less, and when the ridges are concentric, they are adjacent to each other. The interval between the ridges is preferably in the range of 0.2 mm or more and 1.3 mm or less.
JP-A-10-115349 JP 59-29862 A JP 61-48656 A JP 2001-65651 A JP-A-2-236045 JP 2002-213580 A

  In FIG. 6 and FIG. 7 showing the prior art, the engagement diameter of the belt 14 in the pulley assembly 10 is relatively large as R1, and the engagement diameter of the belt 14 in the pulley assembly 12 is R2. When the pulley assembly 10 is on the driving side and the pulley assembly 12 is on the driven side, the gear ratio is in a speed increasing state of 1 or less. Conversely, the pulley assembly 12 is on the driving side. When the pulley assembly 10 is on the driven side, the transmission gear ratio is in a deceleration state of 1 or more.

  In such a continuously variable transmission, when the gear ratio should be changed, the linear actuators 28 and 44 are operated to bring the pair of pulley halves on the side where the belt engagement diameter should be increased closer to each other, thereby reducing the belt engagement diameter. It is reciprocal to move the pair of pulley halves on the side to be moved away from each other. At this time, in order to increase the belt hanging diameter by pressing the pair of pulley halves together, the friction coefficient between the pulley and the belt in the radial direction of the pulley is μr, and the depression angle between the pair of pulleys is α, Assuming that the axial pressing force acting between a pair of pulley halves is F, μrFcos (α / 2) <Fsin (α / 2) must be satisfied, so μr <tan (α / 2) must be satisfied. Otherwise, the belt will not move in the radial direction of the pulley relative to the pulley no matter how strong the force pressing the pair of pulley halves together. Therefore, in this type of belt / pulley type continuously variable transmission, the pulley firing direction between the belt and the pulley is set so that the angle between the pulleys α can be made smaller and a compact design can be facilitated. The friction coefficient is as small as possible, and the friction coefficient in the pulley circumferential direction between the belt and the pulley is as large as possible so as to obtain a higher torque transmission capacity by increasing the degree of engagement in the pulling direction between the pulley and the belt, that is, in the pulley circumferential direction. Is desired.

  On the other hand, in the belt / pulley type continuously variable transmission, excessive wear of the belt receiving surface of the pulley half and the abutting portion of the endless belt is prevented, and noise is suppressed by smoothing the operation of the transmission. Therefore, lubricating oil is applied between the belt receiving surface of the pulley half and the side edge surface of the endless belt. If such lubricating oil is applied in an appropriate amount to form an extremely thin film, it prevents slipping between the belt receiving surface of the pulley half and the side edge surface of the endless belt and increases traction force. Although this is also referred to, if the amount exceeds an appropriate amount, a lubricating action is performed and shifting becomes easy, but the traction force decreases.

  In the belt / pulley type continuously variable transmission as described above, the present invention has a higher torque transmission capacity by increasing the tangential friction coefficient while reducing the radial friction coefficient. In addition, it is an object of the present invention to provide a belt / pulley type continuously variable transmission that is more excellent in ease and speed of shifting.

In order to solve the above problems, the present invention provides an endless belt hung between a plurality of pulley assemblies each including a pair of pulley halves each having a pair of opposed substantially conical belt receiving surfaces. The belt / pulley type continuously variable transmission is configured to transmit the rotational power with the transmission ratio variably controlled between the plurality of pulley assemblies by changing the relative ratio of the belt winding radius in each pulley assembly. In addition, at least one of the pulley halves has a belt receiving surface formed with a multi-annular groove concentric with the central axis of the pulley half and having an edge cut, and the belt receiving surface on which the multi-annular groove is formed. The endless belt is in contact with the endless belt is formed with a parallel groove having a sharp edge along the belt extending direction, and the belt receiving surface of the pulley half and the endless belt are engaged with each other. Before in the area to start Belt / pulley, characterized in that the edges of both grooves is adapted to the lubricating oil is scraped off from the side edge surface of the belt-receiving surface and the endless belt of the pulley half by scissors effect squeezing the other diagonally to each other A continuously variable transmission is proposed. Here, the substantially conical belt receiving surface is not limited to a geometrically exact conical shape of the belt receiving surface, and is substantially equivalent to the configuration of the belt / pulley type continuously variable transmission. This means that it may have a shape that can be operated.

  In this case, the pitch of the multiple annular grooves and the pitch of the parallel grooves may be substantially equal to each other.

An endless belt is spanned between a plurality of pulley assemblies each having a pair of pulley halves each exhibiting a pair of opposing substantially conical belt receiving surfaces, and the belt wraps in each pulley assembly In a belt / pulley type continuously variable transmission that transmits rotational power whose gear ratio is variably controlled between the plurality of pulley assemblies by changing the relative ratio of radii, the belt receiving surface of the pulley is smoothly continuous. In the case of the surface, even if the side edge surface of the belt is provided with parallel grooves along the belt extending direction as in the example described with reference to FIG. 8, the friction coefficient μr in the radial direction and the circumferential direction The friction coefficient μt of the belt is still almost the same, and lubricating oil (traction oil) is applied, which reduces the friction coefficient of the movement of the belt in the radial direction of the pulley relative to the belt receiving surface of the pulley, and makes the shift more variable. Done easily Even now so that, although also decreases corresponds to the decrease amount of the friction coefficient traction parallel grooves sheer is edge along the belt extension direction the side edge surface of the endless belt as described above is formed In addition to the above, a plurality of annular grooves concentric with the central axis of the pulley half on the belt receiving surface of the pulley half that abuts the side edge surface of the endless belt thus formed with parallel grooves As will be described below with reference to FIG. 2, in the region where the belt side edge surface and the belt receiving surface of the pulley half start to engage, the edge of the parallel groove is multiplexed. Due to the `` cracking effect '' due to the gradual engagement with the edge of the annular groove obliquely to each other, the oil film is better scraped off from both the belt side edge surface and the belt receiving surface of the pulley half, The oil film is optimally suppressed and controlled in the pulley engagement area. Contact Bell and pulley exhibits have frictional resistance can be surely obtained.

  On the other hand, when the belt engagement diameter is changed when changing the gear ratio, the belt side edge surface simply moves in the radial direction with respect to the belt receiving surface of the pulley half. On the contrary, the parallel groove of the belt and the multiple annular groove of the pulley are mutually connected between the grooves by the lubricant stored in the groove every time the belt moves in the radial direction with respect to the pulley by the distance of the groove pitch. A state where the contact surface is moistened is obtained, and the radial movement of the belt relative to the pulley is better lubricated and lightened.

  If the pitch of the multiple annular grooves and the pitch of the parallel grooves are substantially equal to each other, the contact area between the belt side edge surface and the belt receiving surface of the pulley half is formed by the formation of these grooves. The degree of reduction is minimized, which is advantageous in increasing the torque transmission capacity of the transmission as much as possible. This will be further described later.

  FIG. 1 shows that the pulley halves 10a and 12a of the conventional belt / pulley type continuously variable transmission shown in FIG. 6 have multiple annular grooves 110g and 112g concentric with the central axis of the pulley halves according to the present invention. It is an arrow view of the side surface of the half of the continuously variable transmission similar to FIG. 6 which shows one formed embodiment. The pulley halves 110a and 112a are the same as the pulley halves 10a and 12a, except that multiple annular grooves 110g and 112g are formed, respectively. A similar multiple annular groove is preferably provided in the other pulley half paired with the pulley halves 110a and 112b, but this is not essential. The endless belt 14, which is stretched between the pulley halves provided with the multiple annular grooves 110g and 112g and operates, may be the same as that of the conventional example described with reference to FIGS. In that case, for reasons explained later, the pitch of the parallel grooves 58 provided on the side edge surface of the belt, particularly the side edge surface 56 of the belt block in the illustrated example, and the pitch of the multiple annular grooves 110g and 112g are substantially equal. Preferably they are the same.

  FIG. 2 shows that the above-described multiple annular grooves 110g or 112g and the parallel grooves 58 formed on the side edge surface of the belt are formed at the same pitch, and are simply aligned with each other. Therefore, it is the schematic shown by the display of only a groove | channel. Therefore, a belt receiving surface of the pulley or a side edge surface of the belt exists in a portion between these adjacent grooves. Here, each one of these between the grooves is referred to as a land portion. Now, it is assumed that the multiple annular grooves 110g or 112g are rotated in the clockwise direction as indicated by the arrows by the rotation of the pulley, and the parallel grooves 58 of the belt are also moved in the direction of the arrows accordingly.

  Then, in the region indicated by S in the figure, the land portions between the multiple annular grooves 110g or 112g and the land portions between the parallel grooves 58 are substantially in contact with each other, and the other is inclined at each edge. Polymerization is gradually performed while squeezing, and the region indicated by F in the figure is moved while maintaining the polymerization state. Due to this operating phenomenon, the oil film or oil droplets adhered to the surfaces of the land portions between the multiple annular grooves 110g or 112g and the land portions between the parallel grooves 58 before they meet each other, In the process of gradually superimposing each other at an angle with each other, when the ridges close the blades, the ridges act on each other as if they were scraping other blade surfaces, so that they are adjacent to each other from above each land. The two lands have the optimal oil film evenly held on a very thin traction that is not thick enough to lubricate and slide between them. In this way, high frictional contact is obtained that brings high torque transmission capability between the two over the entire region F.

  On the other hand, when the belt hanging diameter on the pulley half 110a or 112a is to be increased or decreased to change the transmission ratio, the movement of the parallel groove 58 of the belt with respect to the multiple annular grooves 110g or 112g In the radial direction. In the relative movement of the two land portions in the radial direction, the movement between the two is a movement of moving the multiple annular grooves and the parallel grooves in parallel with each other, and the above-described wrinkle effect no longer occurs. In this case, every time a distance corresponding to one pitch of the groove is generated between the land portions, the lubricating oil is supplied from both grooves to the land portions, whereby a sufficient oil film is formed between the two land portions. The coefficient of friction in the relative movement between the two in the radial direction is greatly reduced.

  As an example, FIG. 3 shows that when the groove width ratio (= groove width / pitch) of the pulley multiple annular groove and the belt parallel groove is 1/4, (A) the pitch of the belt parallel groove becomes the pulley multiple annular groove. When equal (Pb = Pp), (B) When the pitch of the belt parallel groove is 1.05 times the pulley multiple annular groove (Pb = 1.05Pp), and (C) The pitch of the belt parallel groove is pulley multiplexed. In the case where the pitch of the annular groove is 0.95 times (Pb = 0.95Pp), the contact area between the pulley and the belt land portion is exactly the same in one groove. It is a figure shown by contrast about a state. In the figure, the length indicated by a is the contact length between the pulley and the belt land for 5 pulley grooves in the case of (A), and the length indicated by b is the length of (B) above. In this case, the contact length between the pulley and the belt land portion for the pulley groove 5 pitch, and the length indicated by c is the pulley and belt land portion for the pulley groove 5 pitch in the case (C). The contact length between.

  In the same way, when the groove width ratio (= groove width / pitch) of the pulley multiple annular groove and the belt parallel groove is 1/4, (A) When the belt parallel groove pitch is equal to the pulley multiple annular groove (Pb = Pp), (B) When the pitch of the belt parallel groove is 1.10 times the pulley multiple annular groove (Pb = 1.10Pp), (C) The pitch of the belt parallel groove is the pulley multiple annular groove FIG. 4 shows how the contact area between the pulley and the land portion of the belt is different when the pitch is 0.90 times (Pb = 0.90 Pp).

  Similarly, when the groove width ratio (= groove width / pitch) of the pulley multiple annular groove and the belt parallel groove is 1/4, (A) the belt parallel groove pitch is equal to the pulley multiple annular groove. (Pb = Pp), (B) When the pitch of the belt parallel groove is 1.20 times the pulley multiple annular groove (Pb = 1.20Pp), and (C) The pitch of the belt parallel groove is the pulley multiple annular groove. FIG. 5 shows how the contact area between the pulley and the land portion of the belt differs when the pitch is 0.90 times (Pb = 0.90 Pp).

  From these figures, the belt is obtained by obtaining the above-described wrinkle effect in the region S and scraping the oil film from the land portion of the pulley and the belt while keeping the contact area between the land portions in the region F as large as possible. It will be understood that the multiple annular grooves of the pulley and the parallel grooves of the belt preferably have the same pitch in order to increase the torque transmission capability between the pulleys. Actually, the relative positional relationship between the multiple annular grooves of the pulley and the parallel grooves of the belt varies in various ways within the range of one pitch, but according to the result of the same analysis conducted by the inventor. For example, it is preferable that the multiple annular grooves of the pulley and the parallel grooves of the belt have the same pitch even if the relative positional relationship between the multiple annular grooves of the pulley and the parallel grooves of the belt changes variously. It was confirmed that there was no change.

  In addition, based on the operating principle of the present invention described above, selection of the pitch and width ratio of the multiple annular grooves of the pulley and the parallel grooves of the belt, the groove depth, the groove depth, the groove cross-sectional shape, etc., when implementing the present invention These are design matters that may be appropriately selected according to the specifications of each belt / pulley type continuously variable transmission, and it will be apparent that the technical scope of the present invention is not limited.

  While the present invention has been described in detail with respect to one embodiment thereof, it will be apparent to those skilled in the art that various modifications can be made within the scope of the present invention.

The side view of the half which shows one embodiment of the belt / pulley type continuously variable transmission by this invention. Schematic explaining the interaction of pulley multiple annular grooves and belt parallel grooves provided on the pulley and belt according to the present invention. Explanatory drawing which shows the influence which the pitch relationship of a pulley multiple annular groove and a belt parallel groove exerts on the torque transmission capacity of a continuously variable transmission about one example. An explanatory view showing the influence which the pitch relation of a pulley multiple annular groove and a belt parallel groove exerts on the torque transmission capacity of a continuously variable transmission about another example. An explanatory view showing the influence which the pitch relation of a pulley multiple annular groove and a belt parallel groove exerts on the torque transmission capacity of a continuously variable transmission about another example. The side view of the half shown in the form corresponding to embodiment of the belt / pulley type continuously variable transmission by this invention which shows the prior art example of a belt / pulley type continuously variable transmission shown in FIG. FIG. 7 is an illustrative plan view of the belt / pulley type continuously variable transmission shown in FIG. 6. The perspective view which takes out and shows one of the belt blocks.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10,12 ... Pulley assembly, 10a, 10b, 12a, 12b ... Pulley half, 14 ... Endless belt, 16 ... Shaft, 18 ... Housing, 20, 22 ... Bearing, 24 ... Spline, 26 ... Grooved flange, 28 ... Linear actuator, 30 ... Movable element, 32 ... Gear, 34 ... Shaft, 36, 38 ... Bearing, 40 ... Spline, 42 ... Grooved flange, 44 ... Linear actuator, 46 ... Movable element, 48 ... Gear, 50 ... Belt Block 52: Side slit 54 54 Endless belt sheet 56 Side edge surface 58 Parallel groove 110a 112b Pulley half 110g 112g Multiple annular groove

Claims (2)

An endless belt is spanned between a plurality of pulley assemblies each having a pair of pulley halves each exhibiting a pair of opposing substantially conical belt receiving surfaces, and the belt wraps in each pulley assembly A belt / pulley type continuously variable transmission that transmits rotational power whose transmission ratio is variably controlled between the plurality of pulley assemblies by changing a relative ratio of radii, wherein at least one of the pulley halves is the belt. The receiving surface is formed with a multi-annular groove concentric with the central axis of the pulley half, and a belt extending to the side edge surface of the endless belt that abuts the belt-receiving surface on which the multi-annular groove is formed. Parallel grooves having sharp edges along the existing direction are formed, and the edges of both grooves are mutually in a region where the belt receiving surface of the pulley half and the side edge surface of the endless belt start to engage with each other. The other side is slanted and has a great effect Ri said pulley halves of a belt receiving surface and the endless, characterized in that from the side edge surface of the belt so that the oil film is taken stripped belt / pulley type continuously variable transmission. Belt / pulley type continuously variable transmission according to claim 1, characterized in that it is equally properly to each other and the pitch of the parallel groove and a pitch of said multiple annular groove.

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