JP5189566B2 - Method of setting pulley V surface inclination angle in metal belt type continuously variable transmission and metal belt type continuously variable transmission - Google Patents

Description

According to the present invention, a metal belt supporting a number of metal elements is wound around a metal ring assembly around a pulley V surface of a drive pulley supported by a drive shaft and a pulley V surface of a driven pulley supported by a driven shaft. Pulley V surface inclination angle setting method in a metal belt continuously variable transmission that changes the groove width by hydraulically pressing the movable pulley half against the pulley and the fixed pulley half of the driven pulley, and The present invention also relates to a metal belt type continuously variable transmission in which the pulley V surface inclination angle is set using the method .

  In such a metal belt type continuously variable transmission, the pulley V surface inclination angle α of the pulley V surface contacting the metal element is defined as an angle formed by the pulley V surface with respect to the pulley rotation surface (a plane orthogonal to the rotation axis). (See FIG. 1).

In such a metal belt type continuously variable transmission, when the static friction coefficient between the pulley V surface and the metal element is μs and the dynamic friction coefficient is μa, the pulley V surface inclination angle α is set to tan ⁻¹ μa <α <tan. It is known from Patent Document 1 below that a range satisfying ⁻¹ μs and a reduction in transmission efficiency η of a metal belt type continuously variable transmission is set so as not to hinder practical use.

  Further, in such a metal belt type continuously variable transmission, when Nx is a load in the axial direction of the pulley, R is a radius of the arc of the metal belt wound around the pulley, and λ is a pulley V surface inclination angle, The relationship between the maximum transferable torque T at the input rotational speed of 4300 rpm in the acceleration ratio state and the effective friction coefficient μtan is μtan = (T · cosλ) / (Nx · 2 · R), and the pulley V surface inclination angle λ Is less than 11 ° (0.19 rad), the effective coefficient of friction μtan is within a tolerance of 10% of a value of 0.7367 times the pulley V surface inclination angle λ in rad, and from 0.06 It is known from Patent Document 2 below that the durability of the metal belt is improved by setting a larger value.

Japanese Patent No. 3660047 Japanese Patent No. 3453307

  However, any of those described in Patent Documents 1 and 2 only disclose the relationship between the friction coefficient between the pulley and the metal element, the pulley V surface inclination angle, and the maximum transmittable torque. No consideration has been given to the change in transmission efficiency when the V-plane inclination angle is changed, and there remains room for improving the transmission efficiency by appropriately setting the pulley V-plane inclination angle.

  The present invention has been made in view of the above circumstances, and in a metal belt continuously variable transmission, by appropriately setting the pulley V surface inclination angle, the transmission efficiency is improved while ensuring the durability of the metal belt. For the purpose.

In order to achieve the above object, according to the first aspect of the present invention, a metal ring assembly is provided on the pulley V surface of the drive pulley supported by the drive shaft and the pulley V surface of the driven pulley supported by the driven shaft. A metal belt supporting a large number of metal elements is wound around and the movable pulley half is pressed against the fixed pulley halves of the drive pulley and the driven pulley by hydraulic pressure to change the groove width to change speed. In the metal belt type continuously variable transmission, when the fixed pulley half and the movable pulley half are parallel to each other and have a predetermined groove width, the metal belt is wound around the pulley V surface. when the trajectory and the theoretical trajectory of geometric velocity ratio, at a portion where the metal belt is chewing Komu portion or leaving the pulley V-face, the gold And the maximum radius of the trajectory at the position where the belt is pushed outward from the theoretical track, in an intermediate portion between the portion where the metal belt is disengaged and the pulley V-face chewing Komu portion, the metal belt than the theoretical trajectory pulleys V in even the metal belt type continuously variable transmission maximum track deviation amount is the difference between the minimum radius of the raceway at a position drawn inwardly and sets the pulley V-face inclination angle so as to minimize A method for setting the surface inclination angle is proposed.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the maximum track deviation amount is a value at a speed ratio or a minimum speed ratio at which the maximum vehicle speed is obtained. A pulley V surface inclination angle setting method in a belt type continuously variable transmission is proposed.

According to a third aspect of the present invention, there is provided a metal belt type continuously variable transmission in which the pulley V surface inclination angle is set by the method of claim 1 or 2, wherein the pulley V surface inclination angle is set. A metal belt type continuously variable transmission characterized by 9 ° is proposed.

According to the configuration of claim 1, in the continuously variable transmission of the metal belt type , when the movable pulley half is pressed against the fixed pulley half of the pulley by hydraulic pressure, both halves become non-parallel. When the radius of the track where the belt wraps around the pulley V surface changes in an increasing direction and a decreasing direction with respect to the radius of the geometrical velocity ratio theoretical track, the maximum track which is the difference between the maximum radius and the minimum radius Since the pulley V surface inclination angle is set so that the amount of deviation is minimized, both halves of the pulley are non-parallel and the degree of deviation of the metal belt track from the theoretical track can be minimized. It is possible to suppress the occurrence of energy loss due to the metal element strongly rubbing against the pulley V surface, and to improve the transmission efficiency of the metal belt type continuously variable transmission.

  According to the second aspect of the present invention, since the maximum amount of track deviation is a value in the speed ratio (TOP) or the minimum speed ratio (OD) at which the maximum vehicle speed is obtained, the speed ratio that is most frequently used while the vehicle is running. The transmission efficiency can be increased in the area.

According to the third aspect of the present invention, since the pulley V surface inclination angle is set to 9 ° , the maximum transmission efficiency can be obtained in all speed ratio regions.

The longitudinal cross-sectional view of a metal belt type continuously variable transmission. The schematic diagram which shows the relationship between the inclination of a pulley half body, and the track | orbit of a metal belt. The graph which shows the relationship between the pulley V surface inclination | tilt angle and durability of a metal belt. The graph which shows the relationship between the winding angle of a metal belt, and the radius of the track | orbit of a metal belt. The graph which shows the relationship between V surface inclination | tilt angle and the maximum track | orbit deviation | shift amount about each input torque. The principal part enlarged view of the graph of FIG. The graph which shows the relationship between V plane inclination angle and a transmission efficiency difference.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, a transmission case 11 of a metal belt type continuously variable transmission T for a hybrid vehicle using an engine E and an electric motor M as drive sources is provided on a left mission case 12 and a left side surface of the right mission case 12. A left mission case 14 coupled with bolts 13... And a mission case cover 17 coupled with bolts 16 with a partition wall 15 sandwiched between the left side surface of the left mission case 14.

  The drive shaft 20 is supported by ball bearings 18 and 19 provided in the left mission case 14 and the partition wall 15, respectively, and the input shaft 10 is indirectly supported, and roller bearings 21 provided in the left mission case 14 and the partition wall 15 respectively. The driven shaft 23 is supported by the ball bearing 22 and the reduction shaft 26 is supported by the ball bearings 24 and 25 provided in the right mission case 12 and the left mission case 14, respectively, and provided in the right mission case 12 and the left mission case 14, respectively. The differential gear 29 is supported by the ball bearings 27 and 28.

  The electric motor M includes a stator 30 positioned on the radially outer side and a rotor 31 positioned on the radially inner side. The stator 30 is fixed to the motor housing 33 with bolts 32. It is coupled to the shaft 34 and splined to the right end of the input shaft 10 that protrudes to the right from the right mission case 12 via the flywheel 35.

  A planetary gear type forward / reverse switching mechanism 41 is disposed at the left end of the input shaft 10, and the forward / reverse switching mechanism 41 allows the drive shaft 20 supported on the outer periphery of the input shaft 10 to be forward-rotated or reverse-rotated to the input shaft 10. Combined as possible. A drive pulley 42 is provided on the drive shaft 20. A driven pulley 43 is provided on the driven shaft 23, and the drive pulley 42 and the driven pulley 43 are connected by a metal belt 44. Further, a wet multi-plate start clutch 45 is provided at the right end of the driven shaft 23, and the first reduction gear 46 supported on the driven shaft 23 so as to be relatively rotatable is coupled to or released from the driven shaft 23.

  The reduction shaft 26 is provided with a second reduction gear 47 that meshes with the first reduction gear 46 and a final drive gear 48, and the final drive gear 48 meshes with a final driven gear 49 of the differential gear 29. Drive wheels (not shown) are connected to axles 50, 50 extending from the differential gear 29 through the right mission case 12 and the left mission case 14 to the left and right.

  Therefore, the driving force of the engine E is: crankshaft 34 → rotor 31 of electric motor M → flywheel 35 → input shaft 10 → forward / reverse switching mechanism 41 → drive shaft 20 → drive pulley 42 → metal belt 44 → driven pulley 43 → The driven shaft 23 → the engaged starting clutch 45 → the first reduction gear 46 → the second reduction gear 47 → the reduction shaft 26 → the final drive gear 48 → the final driven gear 49 → the differential gear 29 → the axles 50 and 50 to drive wheels. Communicated. When the electric motor M is driven, the driving force is input from the rotor 31 to the input shaft 10 via the flywheel 35.

  Meanwhile, the gear ratio of the metal belt type continuously variable transmission T can be controlled steplessly by changing the effective diameters of the drive pulley 42 and the driven pulley 43 around which the metal belt 44 is wound by hydraulic control. Since the control of the gear ratio of the metal belt type continuously variable transmission T is a well-known technique, a detailed description thereof is omitted here.

  FIG. 2 schematically shows the drive pulley 42 supported by the drive shaft 20. The metal belt 44 is configured by supporting a large number of metal elements 51... On a pair of metal ring assemblies 52, 52 formed by laminating a plurality of metal rings. The surfaces Pe and Pe abut against the pulley V surfaces Pp and Pp of the fixed pulley half 42a and the movable pulley half 42b of the drive pulley 42.

  The fixed pulley half 42a and the movable pulley half 42b of the drive pulley 42 are originally arranged in a direction orthogonal to the drive shaft 20, but are movable with respect to the fixed pulley half 42a. When the pulley half 42b is pressed hydraulically, the groove width is difficult to reduce in the portion where the metal belt 44 is wound, whereas the groove width is likely to decrease in the portion where the metal belt 44 is not wound. 20 is slightly bent, and the stationary pulley half 42a and the movable pulley half 42b are inclined non-parallel.

  Assuming that the fixed pulley half 42a and the movable pulley half 42b of the drive pulley 42 are parallel to each other, the pulley contact surfaces Pe and Pe of each metal element 51 are fixed to the fixed pulley half 42a and the movable pulley. The orbit radius of the portion of the half body 42b that contacts the pulley V surfaces Pp and Pp should be a constant value R0 (theoretical orbit radius of the geometric velocity ratio). However, in practice, the fixed pulley half 42a and the movable pulley half 42b become non-parallel due to the bending of the drive shaft 20, so that the metal belt 44 is engaged with the pulley V surfaces Pp and Pp (or the pulley). The groove widths of the fixed pulley half 42a and the movable pulley half 42b are relatively small W1 in the portions separated from the V planes Pp and Pp), and the metal element 51 is pushed out of the theoretical trajectory having the radius R0. Thus, the orbit radius increases to the maximum value R1. On the contrary, at the intermediate position between the portion where the metal belt 44 is engaged with the pulley V surfaces Pp and Pp and the portion where the metal belt 44 separates from the pulley V surfaces Pp and Pp, the stationary pulley half 42a and the movable pulley half 42b The groove width is relatively large W2, and when the metal element 51 is drawn inside the theoretical orbit having the radius R0, the orbit radius is reduced to the minimum value R2.

  By the way, when the fixed pulley halves 42a and 43a and the movable pulley halves 42b and 43b are parallel to each other, the gear ratio of the metal belt type continuously variable transmission T depends on the groove widths of the drive pulley 42 and the driven pulley 43. It is determined uniquely. The theoretical trajectory of the geometric speed ratio means that the metal belt 44 is a pulley V when the fixed pulley halves 42a and 43a and the movable pulley halves 42b and 43b are parallel to each other and have a predetermined groove width. It is defined as the trajectory of the portion that engages with the planes Pp and Pp. The theoretical trajectory is a precise arc, and its radius is R0.

  In FIG. 2, the white arrows indicate that the contact portions between the pulley contact surfaces Pe, Pe of each metal element 51 and the pulley V surfaces Pp, Pp of the stationary pulley half 42a and the movable pulley half 42b are theoretical trajectories. The state which shifted | deviated outside is shown. A black arrow indicates a state in which the contact portion is shifted to the inside of the theoretical trajectory. As described above, when the contact portions of the pulley contact surfaces Pe and Pe and the pulley V surfaces Pp and Pp are shifted outward or inward with respect to the theoretical trajectory, the pulley contact surfaces Pe and Pe and the pulley V surfaces Pp and Pp There is a problem that the transmission efficiency of the metal belt type continuously variable transmission T decreases due to a large frictional force acting on the contact portion.

  The reason is that when the track of the metal element 51... Changes in the radial direction at the portion where the metal belt 44 is wound around the drive pulley 42, the peripheral speed of the pulley V surfaces Pp and Pp at the portion where the radius of the track is small decreases. Since the moving speed of the metal elements 51 is the same as the moving speed of the metal belt 44 in spite of the fact that the peripheral speed of the pulley V surfaces Pp, Pp in the portion where the radius is large increases, the pulley contact surface It is considered that Pe and Pe strongly rub against the pulley V surfaces Pp and Pp and energy loss occurs.

  In the present invention, the angle formed by the pulley V surfaces Pp, Pp of the stationary pulley half 42a and the movable pulley half 42b with respect to the plane perpendicular to the drive shaft 20 (hereinafter referred to as pulley V surface inclination angle α: FIG. By appropriately setting (see), the fixed pulley half 42a and the movable pulley half 42b are maintained in a parallel state as much as possible, and the transmission efficiency of the belt type continuously variable transmission T is increased.

  FIG. 3 is a graph showing the relationship between the pulley V surface inclination angle α and the durability of the metal belt 44. It can be seen that the durability of the metal belt 44 improves as the pulley V surface inclination angle α decreases. However, in the conventional method for determining the optimum pulley V surface inclination angle α from the friction coefficient between the pulley V surfaces Pp, Pp and the pulley contact surfaces Pe, Pe, the pulley V surface inclination angle α, and the maximum transmission torque, Although the durability of the metal belt 44 can be increased, the transmission efficiency of the metal belt type continuously variable transmission T cannot always be increased.

  Next, a method of setting the pulley V surface inclination angle α at which the maximum transmission efficiency of the metal belt type continuously variable transmission T is obtained will be described.

  FIG. 4 shows the amount of deviation of the actual track from the theoretical track of the metal belt 44 at each position of the winding angle of the metal belt 44 with respect to the drive pulley 42 (0 ° at the pulley inlet and 210 ° at the pulley outlet). At the pulley entrance, the radius of the actual track is the maximum track radius R1 and is shifted to the plus side with respect to the theoretical track radius R0, from which the radius of the actual track gradually decreases and the radius R0 of the theoretical track is shifted to the minus side. It becomes below and becomes the minimum orbit radius R2. After that, the radius of the actual track gradually increases from the minimum track radius R2 and exceeds the radius R0 of the theoretical track, and the radius of the actual track becomes the maximum track radius R1 at the pulley exit.

  When the deviation (absolute value) of the maximum orbit radius R1 with respect to the theoretical orbit radius R0 is G1, and the deviation (absolute value) of the minimum orbit radius R2 with respect to the theoretical orbit radius R0 is G2, the maximum orbit deviation G is G = G1 + G2.

  FIG. 5 shows changes in the maximum track deviation amount G with respect to the V-plane inclination angle α for each input torque Tin of the metal belt type continuously variable transmission T. It can be seen that at any input torque Tin, when the V-plane inclination angle α is 9 °, the maximum trajectory shift amount G is minimum. The V-plane inclination angle α of 9 ° is a value smaller than 11 °, which is a conventional general V-plane inclination angle α serving as a reference, and the metal belt 44 compared to the V-plane inclination angle α = 11 °. The durability is improved (see FIG. 3). The fact that the maximum trajectory deviation G is minimized means that the trajectory of the metal elements 51 at the portion wound around the drive pulley 42 approaches the theoretical trajectory, whereby the pulley contact surfaces Pe, Pe. Compared with the case where other V-plane tilt angles α including 11 ° which is a general V-plane tilt angle α are adopted, minimizing energy loss due to the friction between the pulley V planes Pp and Pp strongly. The transmission efficiency of the metal belt type continuously variable transmission T can be increased.

  FIG. 6 is an enlarged view of a part of FIG. 5 (portion where the V-plane tilt angle α = 8 ° to 11 °). When the input torque Tin is 98 Nm, the V-plane tilt angle α is 8.4. In the range of not less than 1 ° and less than 11.0 °, the maximum trajectory deviation G is smaller than the maximum trajectory deviation G when the reference V-plane inclination angle α = 11 °, and the metal belt type continuously variable transmission T The transmission efficiency can be improved. When the input torque Tin is 128 Nm or 147 Nm, the V-plane tilt angle α = the maximum trajectory deviation amount G is within the range where the V-plane tilt angle α is 8.4 ° or more and less than 11.0 °. It becomes smaller than the maximum track deviation amount G in the case of 11 °, and the transmission efficiency of the metal belt type continuously variable transmission T can be improved.

  Therefore, by setting the V-plane inclination angle α in the range of 8.4 ° or more and less than 11.0 °, the maximum amount of track deviation G can be kept smaller than the conventional one regardless of the value of the input torque Tin. The transmission efficiency of the continuously variable transmission T can be increased.

  FIG. 7 shows the transmission efficiency difference with respect to the V-plane inclination angle α for each gear ratio of the metal belt type continuously variable transmission T. In any of the gear ratios LOW (low), MID (medium), TOP (top), and OD (overdrive), the transmission efficiency is maximized when the V-plane inclination angle α = 9 °. In the region where the V-plane inclination angle α exceeds 9 °, the transmission efficiency at TOP and MID is maximized, and the transmission efficiency at LOW and OD is almost the same. Further, in the region where the V-plane inclination angle α is less than 9 °, the transmission efficiency at OD is maximized, and the transmission efficiency gradually decreases toward TOP, LOW, and MID.

  Therefore, even if the V-plane inclination angle α is determined so that the maximum trajectory shift amount G is minimized at the gear ratio of TOP to OD that is most frequently used during driving of the vehicle, the value is 9 °. If the V-plane inclination angle α is set to 9 °, the maximum transmission efficiency can be obtained in all speed ratio regions.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, in the embodiment, the drive pulley 42 supported mainly on the drive shaft 20 has been described, but the present invention can be similarly applied to the driven pulley 43 supported on the driven shaft 23.

  The structure of the metal belt type continuously variable transmission T shown in FIG. 1 is only an example, and the present invention can be applied to the metal belt type continuously variable transmission T having an arbitrary structure.

  Further, the structure of the metal belt 44 is not limited to the structure in which a large number of metal elements 51 are supported on the two metal ring assemblies 52 of the embodiment, and a large number of metal elements 51. It may be one that supports.

20 Drive shaft 23 Driven shaft 42 Drive pulley
42a stationary pulley half
42b movable pulley half 43 driven pulley
43a fixed pulley half
43b Movable pulley half 44 Metal belt 51 Metal element 52 Metal ring assembly G Maximum track deviation Pp Pulley V surface R1 Maximum track radius R2 Minimum track radius α Pulley V surface tilt angle

Claims (3)

The metal ring assembly (52 ) Is wound around a metal belt (44) supporting a number of metal elements (51) and is movable with respect to the stationary pulley halves (42a, 43a) of the drive pulley (42) and the driven pulley (43). In the metal belt type continuously variable transmission that changes the groove width by pressing the pulley halves (42b, 43b) hydraulically ,
When the fixed pulley half (42a, 43a) and the movable pulley half (42b, 43b) are parallel to each other and have a predetermined groove width, the metal belt (44) has the pulley V surface ( when the trajectory of a portion wound around the Pp) and a theoretical trajectory geometric velocity ratio,
The maximum radius (R1) of the track at the position where the metal belt (44) is pushed out of the theoretical track at the portion where the metal belt (44) is engaged with or separated from the pulley V surface (Pp ). And a track at a position where the metal belt (44) is pulled inward from the theoretical track in an intermediate portion between a portion where the metal belt (44) is engaged with the pulley V surface (Pp) and a portion where the metal belt (44) is separated. pulley V at the minimum radius (R2) maximum track deviation amount which is a difference between (G) a metal belt, characterized in that to set the pulley V surface inclination angle (alpha) to minimize CVT Surface tilt angle setting method. 2. The pulley V surface inclination angle in the metal belt type continuously variable transmission according to claim 1, wherein the maximum track deviation amount (G) is a value at a speed ratio or a minimum speed ratio at which a maximum vehicle speed is obtained. Setting method . A metal belt type continuously variable transmission in which the pulley V surface inclination angle (α) is set by the method according to claim 1 or 2,
A metal belt type continuously variable transmission characterized in that the pulley V surface inclination angle (α) is 9 ° .

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