JP3675329B2 - Belt type continuously variable transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a belt type continuously variable transmission used for a transmission of an automobile or the like.
[0002]
[Prior art]
In recent automobile transmissions, a belt type continuously variable transmission called a so-called CVT (Continuously Variable Transmission) is frequently used (for example, see Japanese Patent Application Laid-Open No. 8-219188).
[0003]
In general, in this type of continuously variable transmission, the input pulley and the output pulley have a movable sheave and a fixed sheave, and the movable sheave and the fixed sheave of one pulley are opposite to each other in the axial direction of the other pulley. Is arranged. A V-belt is fitted and wound around a V-groove formed between each movable sheave and the fixed sheave. The driving force of the engine is input to the input side pulley, transmitted to the output side pulley via the V belt, and transmitted from the output side pulley to the axle.
[0004]
The V-belt is configured by stacking a large number of elements having side surfaces that come into contact with the sheave surface of the pulley, arranging them in an annular shape, and winding a flexible ring around each element.
[0005]
The speed change is achieved by moving each movable sheave in the axial direction by the thrust applied by the thrust applying means, changing the winding position of the V belt to change the winding radius of the V belt in each pulley, and changing the input side pulley and the output side pulley. This is performed by steplessly changing the pulley ratio between the pulleys, that is, the gear ratio. The thrust applying means is constituted by, for example, an oil pump driven by an engine, and thrust is applied to each movable sheave by supplying hydraulic oil discharged from the oil pump to the back surface of each movable sheave.
[0006]
[Problems to be solved by the invention]
In order to transmit a required torque by the V-belt, it is necessary to apply a thrust corresponding to the transmission torque capacity to the movable sheave so that the V-belt does not slide with respect to each pulley.
[0007]
In a belt-type continuously variable transmission connected to an engine via a torque converter, slippage of the V-belt with respect to the pulley is likely to occur as in the case where a vehicle having the largest torque amplification of the torque converter starts. This is when the wrapping radius of the V belt in the input pulley is relatively small and the wrapping radius of the V belt in the output pulley is relatively large, that is, when the pulley ratio is relatively large. If an excessive torque is input to the input side pulley when the pulley ratio is large, slippage of the V belt occurs with respect to the input side pulley. Therefore, the transmission torque capacity when the pulley ratio is the maximum almost determines the minimum transmission torque capacity that can be transmitted by the belt type continuously variable transmission.
[0008]
If the thrust applied to the movable sheave by the thrust applying means is increased, slippage of the V belt with respect to the pulley can be prevented, and the transmission torque capacity when the pulley ratio is large can be increased.
[0009]
However, on the other hand, as a result of applying an unnecessarily large thrust, the tensile force acting on the V-belt increases, and the durability of the V-belt may be reduced.
[0010]
Furthermore, in order to apply a large thrust, it is necessary to increase the hydraulic pressure of the hydraulic oil supplied by the oil pump as the thrust applying means, and the driving torque of the oil pump increases. In connection with this, the load of an engine becomes large and causes the malfunction that fuel consumption worsens.
[0011]
In the belt type continuously variable transmission, the inventors have obstructed in improving the transmission torque capacity while satisfying the point that the durability of the V-belt is not lowered and the point that the driving torque of the oil pump is not increased. The cause is considered to be the conventional fixed concept that the sheave surface angle of the input pulley and the sheave surface angle of the output pulley must be set to the same angle, and the sheave surface angle of each pulley is determined under a predetermined condition. Thus, the present invention has been completed by paying attention to the point that the transmission torque capacity can be improved while satisfying the above two points.
[0012]
Therefore, the present invention has been made to solve the problems associated with the above-described conventional technology, and satisfies the point that the durability of the V-belt is not reduced and the point that the driving torque of the oil pump is not increased. It is an object of the present invention to provide a belt type continuously variable transmission capable of improving the capacity.
[0013]
[Means for Solving the Problems]
The object of the present invention is achieved by the following means.
[0014]
  (1) a first pulley having a fixed sheave and a movable sheave, a second pulley having a fixed sheave and a movable sheave, and a thrust applying means for applying a thrust to the fixed sheave to each movable sheave, In the belt-type continuously variable transmission that changes the distance between the fixed sheave and the movable sheave and transmits the rotation from one pulley to the other pulley by a V-belt wound between both pulleys.
  The sheave surface angle in the first pulley is different from the sheave surface angle in the second pulley.And the said V belt has two contact surfaces which contact each pulley from which the angle of a sheave surface differsIn this belt-type continuously variable transmission, the transmission torque capacity of the V-belt is increased without reducing the durability of the V-belt and without increasing the driving torque of the thrust applying means. is there.
[0015]
(2) a first pulley having a fixed sheave and a movable sheave, a second pulley having a fixed sheave and a movable sheave, and a thrust applying means for applying a thrust to the movable sheave to each movable sheave, In the belt-type continuously variable transmission that changes the distance between the fixed sheave and the movable sheave and transmits the rotation from one pulley to the other pulley by a V-belt wound between both pulleys.
Of the first pulley and the second pulley, the sheave surface angle in the pulley on the pulley determining side is set smaller than the sheave surface angle in the pulley on the side determining the pressing force with the V-belt. This is a belt type continuously variable transmission.
[0016]
  (3) The V-belt has two contact surfaces that come into contact with respective pulleys having different sheave surface angles.Above (2)The belt type continuously variable transmission described in 1.
[0017]
(4) The V-belt is configured by winding a flexible ring around each of the elements arranged in an annular shape in a large number of layers,
The belt-type continuously variable transmission according to (3), wherein the two contact surfaces are formed on a side surface of each element.
[0018]
(5) The input-side pulley is connected to a vehicle running engine,
The output pulley is connected to an axle;
In any one of the above (1) to (4), the thrust applying means includes an oil pump that is driven by the engine and supplies hydraulic oil to the back surface of each movable sheave. It is a belt type continuously variable transmission of description.
[0019]
【The invention's effect】
The present invention configured as described above has the following effects.
[0020]
  According to the first aspect of the present invention, the conventional fixed concept that the sheave surface angle of the first pulley and the sheave surface angle of the second pulley must be set to the same angle is overcome, and the sheave in the first pulley is broken. By making the surface angle different from the sheave surface angle in the second pulley, without reducing the durability of the V-belt and without increasing the driving torque of the thrust applying means, the transmission torque capacity by the V-belt, in particular, The transmission torque capacity when the pulley ratio is large can be increased.
Further, the V belt comes into contact with the sheave surface of the first pulley through one contact surface, and comes into contact with the sheave surface of the second pulley through the other contact surface. Since the contact between the V-belt and each pulley does not hit a point, the occurrence of local wear on the sheave surface or the V-belt is prevented or reduced, and stable torque transmission is realized over a long period of time.
[0021]
According to the second aspect of the present invention, the sheave surface angle in the pulley that determines the pulley ratio is smaller than the sheave surface angle in the pulley that determines the pressing force with the V belt. The pressing force of the V-belt against the pulley on the pulley-determining side by the wedge effect without changing the thrust for pushing the pulley on the pulley-determining pressing force, the pressing force of the V-belt against the pulley, and the tensile force of the V-belt Can be increased. As a result, the frictional force between the pulley that determines the pulley ratio and the V-belt is increased, and the slippage of the V-belt can be prevented, and the transmission torque capacity by the V-belt, particularly the transmission torque capacity when the pulley ratio is large is increased. Can be increased. Here, since the tensile force of the V-belt does not change, the durability of the V-belt does not deteriorate, and the thrust for pushing the pulley on the side that determines the pressing force with the V-belt does not change, so the driving torque of the thrust applying means increases. I don't have to. Therefore, as in the first aspect of the invention, the transmission torque capacity by the V-belt, particularly when the pulley ratio is large, without reducing the durability of the V-belt and without increasing the driving torque of the thrust applying means. The transmission torque capacity can be increased.
[0022]
According to the invention described in claim 3, the V belt comes into contact with the sheave surface of the first pulley via one contact surface, and the sheave surface of the second pulley via the other contact surface. Of contact is per surface. Since the contact between the V-belt and each pulley does not hit a point, the occurrence of local wear on the sheave surface or the V-belt is prevented or reduced, and stable torque transmission is realized over a long period of time.
[0023]
According to the fourth aspect of the present invention, each element of the V-belt is in contact with the sheave surface of the first pulley through one contact surface, and the second pulley through the other contact surface. Contact with the sheave surface is per surface. Since the contact between each element and each pulley does not hit a point, the occurrence of local wear on the sheave surface or the element is prevented or reduced, and stable torque transmission is realized over a long period of time.
[0024]
According to the fifth aspect of the present invention, in order to increase the transmission torque capacity, it is not necessary to increase the hydraulic pressure of the hydraulic oil supplied by the oil pump as the thrust applying means, so that the driving torque of the oil pump is increased. Therefore, there is no possibility that the engine load will not increase and the fuel efficiency will deteriorate.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0026]
FIG. 1 is a schematic configuration diagram of a belt-type continuously variable transmission according to an embodiment of the present invention.
[0027]
As shown in FIG. 1, a belt type continuously variable transmission 10 includes an input shaft 15 connected to an output shaft 14 of an engine 13 via a torque converter 11 and a clutch 12, and an output shaft 16 connected to an axle of a vehicle. And an input side pulley 20 (corresponding to the first pulley) provided on the input shaft 15 and an output side pulley 30 (corresponding to the second pulley) provided on the output shaft 16. A V-belt 40 is wound around. The input pulley 20 functions as a pulley that determines the pulley ratio, and the output pulley 30 functions as a pulley that determines the pressing force with the V belt 40.
[0028]
The input-side pulley 20 includes a fixed sheave 21 that is connected to the input shaft 15 and rotates integrally with the input shaft 15, and a movable sheave 23 that forms a V-groove 22 so as to face the fixed sheave 21. The movable sheave 23 is slidably provided on the input shaft 15 and can be displaced in the axial direction. An input-side pulley piston chamber 24 is provided on the back side of the movable sheave 23.
[0029]
The output pulley 30 includes a fixed sheave 31 that is connected to the output shaft 16 and rotates integrally with the output shaft 16, and a movable sheave 33 that forms a V groove 32 opposite to the fixed sheave 31. The movable sheave 33 is slidably provided on the output shaft 16 and can be displaced in the axial direction. An output side pulley piston chamber 34 is provided on the back side of the movable sheave 33. The fixed sheave 31 and the movable sheave 33 of the output-side pulley 30 are disposed so as to be opposite to the fixed sheave 21 and the movable sheave 23 of the input-side pulley 20 in the axial direction.
[0030]
The V-belt 40 includes a plurality of elements 41 having side surfaces (flank surfaces) that contact the sheave surfaces 21a, 23a, 31a, 33a of the pulleys 20 and 30, and is arranged in an annular shape so that each element 41 is flexible. The laminated ring 42 is wound around (see FIG. 8A).
[0031]
The belt type continuously variable transmission 10 further includes thrust applying means for applying a thrust to the movable sheaves 23 and 33 to be pressed toward the fixed sheaves 21 and 31. The thrust applying means includes an oil pump 50 that is driven by the engine 13 and supplies hydraulic oil to the back surfaces of the movable sheaves 23 and 33.
[0032]
A line pressure PL from the hydraulic control unit 51 acts on the output-side pulley piston chamber 34, and a shift control pressure PS obtained by reducing the line pressure PL by the shift control valve 52 is applied to the input-side pulley piston chamber 24. Works. In accordance with the differential pressure between the transmission control pressure PS and the line pressure PL, the winding radius of the V-belt 40 around the pulleys 20 and 30 changes steplessly, and the gear ratio changes steplessly. In the hydraulic control unit 51, a line pressure control system (not shown) for adjusting the line pressure PL is provided.
[0033]
Control for changing the widths of the V grooves 22 and 32 of the pulleys 20 and 30 is performed by a CVT control unit 53 mainly composed of a microcomputer. The CVT control unit 53 is connected to an unillustrated engine rotation sensor, throttle opening sensor, input pulley rotation sensor, and output pulley rotation sensor, as well as a solenoid 54 for driving the shift control valve 52 of the hydraulic control unit 51. Has been. The CVT control unit 53 first calculates a target gear ratio based on the driving state of the vehicle, obtains an actual gear ratio based on the actual speed of both pulleys 20 and 30, and uses information on the engine speed and throttle opening. Calculate the transmission torque. Next, the CVT control unit 53 drives the solenoid 54 in accordance with the deviation between the target speed ratio and the actual speed ratio. The CVT control unit 53 further controls the line pressure control system in the hydraulic control unit 51 so that the necessary pulley thrust calculated based on the target gear ratio and the transmission torque can be obtained.
[0034]
By such control, the line pressure PL supplied to the output-side pulley piston chamber 34 and the shift control valve 52 is adjusted, and the shift control valve 52 adjusts the supply and discharge of hydraulic oil to and from the input-side pulley piston chamber 24. The shift control pressure PS is adjusted to a value corresponding to the target gear ratio.
[0035]
The line pressure PL is related to the tension of the V belt 40 wound between the pulleys 20 and 30. If the line pressure PL is increased more than necessary, the tension of the V belt 40 becomes excessive, and the durability of the V belt 40 is increased. Will be reduced. Further, since the driving torque of the oil pump 50 is increased, the load on the engine 13 is increased, resulting in a problem that fuel consumption is deteriorated. On the other hand, if the line pressure PL is low and the tension of the V-belt 40 is too small, not only will the transmission efficiency decrease due to the slippage of the V-belt 40 with respect to the pulleys 20 and 30, but also in this case, the V-belt 40 will wear due to slippage. Durability will also decrease.
[0036]
Below, the relationship between the transmission torque capacity by the V belt 40 and the sheave surface angles of the pulleys 20 and 30 will be considered.
[0037]
As described above, in the belt type continuously variable transmission 10 connected to the engine 13 via the torque converter 11, the V belt 40 and the pulleys 20, 30 are started when the vehicle having the largest torque amplification of the torque converter 11 starts. The transmission torque capacity when the pulley ratio is the maximum is almost the minimum transmission torque capacity that can be transmitted by the belt type continuously variable transmission 10.
[0038]
The transmission torque capacity will be described with reference to FIGS.
[0039]
As shown in FIG. 2, the hydraulic pressure P acting on the output side pulley 30 becomes a thrust force that pushes the movable sheave 33, and the pressing force N <b> 1 of the element 41 against the output side pulley 30 via the sheave surface angle α of the output side pulley 30. become. The element pressing force N1 is one factor that determines the frictional force between the output pulley 30 and the element 41.
[0040]
The hydraulic pressure P acting on the output side pulley 30 becomes a tensile force T that pulls the ring 42 of the V belt 40 via the sheave surface angle α of the output side pulley 30. This ring tension force T becomes the pressing force N2 of the element 41 against the input side pulley 20 via the sheave surface angle α of the input side pulley 20. The element pressing force N2 is one factor that determines the frictional force between the input pulley 20 and the element 41.
[0041]
As shown in FIG. 3, when the pulley ratio is large, the winding angle of the V-belt 40 in each of the pulleys 20 and 30 is such that the winding angle (θ1) in the input-side pulley 20 <the winding in the output-side pulley 30. The angle (θ2). The winding radius of the V-belt 40 is such that the winding radius (r1) of the input side pulley 20 <the winding radius (r2) of the output side pulley 30. For this reason, when an excessive torque is input to the input-side pulley 20, the V-belt 40 slips in the input-side pulley 20. In FIG. 3, a hatched region in the entire length of the V-belt 40 represents a contact range with the pulleys 20 and 30.
[0042]
Under the conventional fixed idea that the sheave surface angle of the input pulley and the sheave surface angle of the output pulley must be set to the same angle, the sheave surface angle of both pulleys 20 and 30 and the flank surface angle of the element 41 Are set to the same angle α (for example, 11 °, etc.).
[0043]
Therefore, as shown in FIG. 4, when the hydraulic pressure acting on the output pulley 30 is increased by ΔP to P + ΔP, the thrust for pushing the movable sheave 33 increases accordingly, and the element pressing force against the output pulley 30 increases by ΔN1. N1 + ΔN1, the ring tensile force increases by ΔT to T + ΔT, and the element pressing force against the input pulley 20 increases by ΔN2 to N2 + ΔN2. The slippage of the V-belt 40 can be prevented and the transmission torque capacity can be increased by the amount that the element pressing force, which is one factor that determines the frictional force between the input pulley 20 and the element 41, has increased by ΔN2.
[0044]
However, since the ring tension acting on the ring 42 of the V-belt 40 is increased by ΔT by increasing the hydraulic pressure acting on the output-side pulley 30 by ΔP, the durability of the V-belt 40, particularly the durability of the ring 42, is increased. May decrease.
[0045]
Further, by increasing the hydraulic pressure acting on the output side pulley 30 by ΔP, the driving torque of the oil pump 50 is increased, the load on the engine 13 is increased, and the fuel consumption is deteriorated.
[0046]
Under the conventional fixed idea that the sheave surface angle of the input side pulley and the sheave surface angle of the output side pulley must be set to the same angle, as shown in FIG. It is also conceivable to set both the flank angle of the element 41 to an angle β (for example, 7 °) that is smaller than the angle α (for example, 11 °) described above.
[0047]
In such a configuration, when the hydraulic pressure acting on the output pulley 30 is increased by ΔP ′ to P + ΔP ′, the thrust force that pushes the movable sheave 33 increases accordingly, and the element pressing force against the output pulley 30 increases by ΔN1 ′. Although N1 + ΔN1 ′, the ring tensile force T is almost the same as the sheave surface angle α because the sheave surface angle β is reduced. Although the ring tension force T does not change, the element pressing force against the input side pulley 20 increases by ΔN2 ′ to N2 + ΔN2 ′ by the amount of the sheave surface angle β being reduced. The slippage of the V-belt 40 can be prevented and the transmission torque capacity can be increased by the amount that the element pressing force, which is one factor that determines the frictional force between the input pulley 20 and the element 41, has increased by ΔN2 ′.
[0048]
Thus, if the sheave surface angle of both pulleys 20 and 30 is reduced, the ring pulling force T does not change even if the thrust pushing the movable sheave 33 is increased. it can.
[0049]
However, the problem that the oil pressure acting on the output-side pulley 30 is increased by ΔP ′ still increases the driving torque of the oil pump 50 and deteriorates the fuel consumption cannot be solved.
[0050]
Therefore, in the belt type continuously variable transmission 10 of the present embodiment, the conventional fixed idea that the sheave surface angle of the input pulley and the sheave surface angle of the output pulley must be set to the same angle is broken. Then, by making the sheave surface angle at the input pulley 20 different from the sheave surface angle at the output pulley 30, the durability of the V-belt 40 is not lowered and the driving torque of the oil pump 50 is not increased. The transmission torque capacity by the V belt 40 is increased.
[0051]
More specifically, as shown in FIG. 6, the sheave surface angle β (for example, 7 °) in the input pulley 20 that determines the pulley ratio of the input pulley 20 and the output pulley 30 is set to Is set smaller (β <α) than the sheave surface angle α (for example, 11 °) in the output-side pulley 30 on the side that determines the pressing force.
[0052]
According to such a configuration, the hydraulic pressure P and the output acting on the output-side pulley 30 are compared with the comparative example (see FIG. 2) in which the sheave surface angles in the input-side pulley 20 and the output-side pulley 30 are set to the same angle α. Since the sheave surface angle α in the side pulley 30 does not change, the thrust for pushing the movable sheave 33, the element pressing force N1 against the output side pulley 30, and the ring tension force T do not change. On the other hand, since the sheave surface angle β in the input side pulley 20 is smaller than the angle α, the element pressing force N3 against the input side pulley 20 is larger than the element pressing force N2 in the proportionality due to the wedge effect (N3> N2). ). As a result of the increase in the element pressing force N3, the frictional force between the input pulley 20 and the element 41 increases, so that the V belt 40 can be prevented from slipping and the transmission torque capacity can be increased. In particular, the transmission torque capacity when the pulley ratio is large is improved.
[0053]
Thus, the transmission torque capacity can be increased without increasing the hydraulic pressure P acting on the output-side pulley 30 and without changing the ring tension force T of the V-belt 40.
[0054]
In order to increase the transmission torque capacity, it is not necessary to increase the hydraulic pressure P acting on the output-side pulley 30, so that the driving torque of the oil pump 50 does not increase, the load on the engine 13 does not increase, and the fuel consumption may deteriorate. Absent. This is because when the frictional force between the input side pulley 20 and the element 41 is set to be the same as that in the case of the proportionality in order to obtain the same transmission torque capacity as that in the case of the proportionality, the hydraulic pressure acting on the output side pulley 30 It means that it can be lowered. In this case, the driving torque of the oil pump 50 can be reduced, and improvement in fuel consumption is expected through a reduction in engine load.
[0055]
Further, since the hydraulic pressure P acting on the output pulley 30 and the sheave surface angle α in the output pulley 30 do not change, the tensile force T applied to the ring 42 of the V belt 40 does not change, and the durability of the ring 42 does not deteriorate.
[0056]
Therefore, according to the belt type continuously variable transmission 10 of the present embodiment, the points that the durability of the V-belt 40 is not lowered and the fuel consumption is not deteriorated without increasing the driving torque of the oil pump 50 are satisfied. On the other hand, it is possible to improve the transmission torque capacity by the V belt 40, in particular, to improve the transmission torque capacity when the pulley ratio is large.
[0057]
FIG. 7 is a diagram showing the transmission torque capacity for each pulley ratio when the sheave surface angle β in the input-side pulley 20 is set smaller than the sheave surface angle α in the output-side pulley 30 (β <α) together with the proportionality. It is.
[0058]
As shown in the figure, when the sheave surface angle β in the input pulley 20 is 1 ° smaller than the sheave surface angle α in the output pulley 30 (α−β = 1 °), the pulley ratio is n (for example, n = 1). As described above, the input torque can be increased and the transmission torque capacity can be improved with respect to the proportionality in which the sheave surface angles in the pulleys 20 and 30 are set to the same angle (α = β). It was confirmed. It was confirmed that when the sheave surface angle in the input-side pulley 20 was 2 ° smaller than the sheave surface angle in the output-side pulley 30 (α−β = 2 °), the transmission torque capacity could be further improved.
[0059]
The preferred sheave surface angle difference is about 2 °, and the upper limit of the sheave surface angle difference is about 4 °. Expressed as a ratio of both sheave surface angles, “the sheave surface angle α in the output pulley 30 / the sheave surface angle β in the input pulley 20” is preferably about 1.22, and the upper limit is about 1.57.
[0060]
The difference in the sheave surface angle is preferably about 2 ° for the reason of achieving compatibility with the belt transmission performance. Further, the reason why the upper limit is set for the difference in sheave surface angle is that the transmission torque capacity is not improved even if the angle difference is further increased.
[0061]
FIGS. 8A to 8D are diagrams for explaining the configuration of the element 41 of the V-belt 40 in the present embodiment.
[0062]
As described above, in this embodiment, the input-side sheave surface angle β is set to be smaller than the output-side sheave surface angle α (β <α). Therefore, as shown in FIG. When the flank surface has only one contact surface having an angle β, when the element 60 comes into contact with the output side pulley 30, an angle difference is generated between the element 60 and the output side pulley 30. Points are awarded at the lower part 61 of the flank surface. When the contact between the element 60 and the output pulley 30 reaches a point, local abnormal wear occurs on the sheave surfaces 31 a and 33 a of the output pulley 30 and the lower portion 61 of the element 60.
[0063]
Therefore, in the present embodiment, the V-belt 40 has two contact surfaces that contact the pulleys 20 and 30 having different sheave surface angles α and β. The two contact surfaces 43 and 44 are formed on the flank surface of each element 41 as shown in FIGS. One contact surface 43 is set to an angle β and is used exclusively for contact with the sheave surfaces 21a and 23a (angle β) of the input pulley 20 (FIG. 8B). The other contact surface 44 is set to an angle α, and is used exclusively for contacting the sheave surfaces 31a and 33a (angle α) of the output-side pulley 30 (FIG. 8C).
[0064]
According to the element 41 of the present embodiment in which the flank surface is a two-step surface having an angle α and an angle β, the contact with the sheave surfaces 21a and 23a of the input-side pulley 20 is per surface contact via the one contact surface 43. Thus, contact with the sheave surfaces 31a and 33a of the output-side pulley 30 comes into contact with the surface via the other contact surface 44. For this reason, generation | occurrence | production of the local abrasion of the sheave surfaces 21a, 23a, 31a, 33a and the element 41 is prevented or reduced, and stable torque transmission is realized over a long period of time.
[0065]
In addition, although embodiment which applied the belt-type continuously variable transmission concerning this invention to the transmission for motor vehicles was described, this invention is not limited to this case. The present invention can also be applied to a continuously variable transmission incorporated in a processing machine or the like.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a belt-type continuously variable transmission according to an embodiment of the present invention.
[Fig. 2] The element pressing force N1, the ring tension force T against the output pulley, the ring pulling force T, against the input pulley when the sheave surface angle of the input pulley and the sheave surface angle of the output pulley are set to the same angle α. It is a conceptual diagram with which it uses for description of element pressing force N2.
FIG. 3 is a diagram showing a winding angle and a winding radius of a V-belt in each pulley when the pulley ratio is large.
[Fig. 4] Element pressing force N1 and ring when the hydraulic pressure to press the output pulley is increased when the sheave surface angle of the input pulley and the sheave surface angle of the output pulley are set to the same angle α. It is a conceptual diagram with which it uses for description of the change of the tensile force T and the element pressing force N2.
FIG. 5: Element pressing force N1, ring tensile force T, element pressing force when the sheave surface angle of the input pulley and the sheave surface angle of the output pulley are set to the same angle β (β <α) It is a conceptual diagram with which it uses for description of N2.
FIG. 6 shows an element pressing force N1, a ring tensile force T, an element pressing force N3 in the present embodiment in which the sheave surface angle β in the input pulley is set smaller than the sheave surface angle α in the output pulley (β <α). It is a conceptual diagram with which it uses for description.
FIG. 7 is a diagram showing, together with proportionality, transmission torque capacity for each pulley ratio when the sheave surface angle β in the input pulley is set smaller than the sheave surface angle α in the output pulley (β <α). .
FIGS. 8A to 8D are diagrams for explaining the configuration of the elements of the V-belt in the present embodiment.
[Explanation of symbols]
10 ... Belt type continuously variable transmission
13 ... Engine
20 ... Input side pulley (first pulley, pulley on the side that determines the pulley ratio)
21 ... Fixed sheave
23. Movable sheave
21a, 23a ... Sheave surface
30 ... Output pulley (second pulley, pulley on the side that determines the pressing force between the V belt)
31 ... Fixed sheave
33 ... Movable sheave
31a, 33a ... Sheave surface
40 ... V belt
41 ... Element
42 ... Ring
43, 44 ... two contact surfaces
50. Oil pump (thrust applying means)
β: Sheave surface angle at the input pulley (sheave surface angle at the first pulley)
α: Sheave surface angle at the output pulley (sheave surface angle at the second pulley)

Claims (5)

A first pulley having a fixed sheave and a movable sheave; a second pulley having a fixed sheave and a movable sheave; and a thrust applying means for applying a thrust to the movable sheave to each movable sheave. In a belt-type continuously variable transmission that changes the distance between the movable sheave and transmits rotation from one pulley to the other pulley by a V-belt wound between both pulleys.
By making the sheave surface angle in the first pulley different from the sheave surface angle in the second pulley , and the V belt has two contact surfaces that contact the respective pulleys having different sheave surface angles , the V belt A belt-type continuously variable transmission characterized in that the transmission torque capacity of the V-belt is increased without lowering the durability and without increasing the driving torque of the thrust applying means. A first pulley having a fixed sheave and a movable sheave; a second pulley having a fixed sheave and a movable sheave; and a thrust applying means for applying a thrust to the movable sheave to each movable sheave. In a belt-type continuously variable transmission that changes the distance between the movable sheave and transmits rotation from one pulley to the other pulley by a V-belt wound between both pulleys.
Of the first pulley and the second pulley, the sheave surface angle in the pulley on the pulley determining side is set smaller than the sheave surface angle in the pulley on the side determining the pressing force with the V-belt. A belt type continuously variable transmission. The belt-type continuously variable transmission according to claim 2 , wherein the V-belt has two contact surfaces that come into contact with respective pulleys having different sheave surface angles. The V-belt is configured by winding a flexible ring around each of the elements arranged in an annular shape in a large number of layers,
The belt-type continuously variable transmission according to claim 3, wherein the two contact surfaces are formed on a side surface of each element. The input side pulley is connected to a vehicle running engine,
The output pulley is connected to an axle;
The said thrust provision means is comprised from the oil pump which drives a hydraulic oil to the back surface of each movable sheave while being driven by the said engine. Belt type continuously variable transmission.

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