JP2012255473A - Power transmission device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the minimum shifting ratio of a power transmission device while highly keeping the transmission efficiency of driving force in a stepless transmission.SOLUTION: The fuel consumption ratio of an engine can be reduced by reducing the total transmission ratio of the stepless transmission T and the power transmission device including an acceleration mechanism 34 while keeping the relatively high transmission efficiency by making the transmission ratio of the stepless transmission T a relatively large value because the power transmission device has an acceleration mechanism 34 accelerating and transmitting the rotation of an output shaft 12 of the stepless transmission T to driving wheel transmission shafts 36, 37. Friction can be reduced by setting friction dampers of the one-way clutches weak by such a degree that a required response frequency of the one-way clutches of the stepless transmission T can be reduced the fluctuation of torque of the output shaft 12 generated by the plurality of one-way clutches operating in order can be reduced by the acceleration mechanism 34 and transmitted to the driving wheel transmission shaft 36, 37.

Description

  The present invention includes a continuously variable transmission that changes the speed ratio by increasing or decreasing the reciprocating stroke of the connecting rod while transmitting the rotation of the input shaft to the output shaft via a connecting rod and a one-way clutch. The present invention relates to a vehicle power transmission device.

  A continuously variable transmission that shifts the rotation of the input shaft connected to the drive source and transmits the rotation to the output shaft includes a plurality of transmission units juxtaposed in the axial direction of the input shaft and the output shaft, Each of the units is provided on an input side fulcrum whose amount of eccentricity from the axis of the input shaft is variable and rotates together with the input shaft, a one-way clutch connected to the output shaft, and an input member of the one-way clutch. A power transmission for a vehicle comprising: an output side fulcrum; a connecting rod which is connected to both ends of the input side fulcrum and the output side fulcrum and reciprocates; and a drive wheel transmission shaft which transmits rotation of the output shaft to drive wheels. An apparatus is known from US Pat.

JP-T-2005-502543

  In FIG. 12, the horizontal axis is the engine speed, the vertical axis is the engine output torque, the lower right line is the constant vehicle speed line, the upper right line is the equal speed ratio line, the contour line is the equal fuel consumption line, The darker the portion, the better the fuel consumption (the fuel consumption rate is lower). The conventional minimum transmission ratio of this type of continuously variable transmission is about 2 to 3, but if this transmission ratio can be further reduced, for example, the engine operating position is moved from point a to point b in FIG. By doing so, it is possible to further reduce the fuel consumption rate.

  However, if the minimum transmission ratio of the continuously variable transmission is reduced, there is a problem that the transmission efficiency of the driving force is lowered. Hereinafter, the reason will be described with reference to FIG.

  FIG. 13 shows the principle of the continuously variable transmission. An input side fulcrum 02 that rotates integrally with the input shaft 01 and an output side fulcrum 05 that rotates integrally with the input member of the one-way clutch 04 provided on the output shaft 03 are shown. Connected by the connecting rod 06, the eccentric amount ε of the input side fulcrum 02 with respect to the input shaft 01 is variable.

  Since the efficiency when the driving force is transmitted from the connecting rod 06 to the one-way clutch 04 increases as the swing angle θ decreases, the swing angle θ decreases (increases the gear ratio) to increase the driving force transmission efficiency. It is difficult to reduce the gear ratio while maintaining high transmission efficiency of the driving force.

  FIG. 14 shows changes in the swing angle θ of the output shaft 03 (one-way clutch 04) and the transmission efficiency of the driving force when the speed ratio of the continuously variable transmission is changed. It can be seen that as the swing angle θ of the shaft 03 increases, the transmission efficiency of the driving force rapidly decreases.

  Further, if the gear ratio of the continuously variable transmission is to be reduced, the eccentric amount ε of the input side fulcrum 02 increases, so that the connecting rod 06 and the bearing that supports it on the input shaft are increased in size and weight. As a result, as shown in FIG. 15, when the maximum speed ratio is reduced, there is a problem that the transmission efficiency of the driving force is reduced in all speed ratio regions.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to reduce the minimum gear ratio of the power transmission device while maintaining high transmission efficiency of the driving force of the continuously variable transmission.

  In order to achieve the above object, according to the first aspect of the present invention, a continuously variable transmission that shifts the rotation of the input shaft connected to the drive source and transmits the rotation to the output shaft includes the input shaft and the input shaft. An input side fulcrum that includes a plurality of speed change units juxtaposed in the axial direction of the output shaft, and each of the speed change units has a variable amount of eccentricity from the axis of the input shaft and rotates together with the input shaft; A one-way clutch connected to the output shaft; an output-side fulcrum provided on an input member of the one-way clutch; a connecting rod that reciprocates with both ends connected to the input-side fulcrum and the output-side fulcrum; and the output A vehicle power transmission device including a drive wheel transmission shaft that transmits rotation of a shaft to a drive wheel, comprising a speed increasing mechanism that accelerates rotation of the output shaft and transmits the rotation to the drive wheel transmission shaft. Features and That vehicular power transmitting device is proposed.

  According to the second aspect of the present invention, in addition to the configuration of the first aspect, the output shaft and the drive wheel transmission shaft are arranged on separate axes, and a differential gear is arranged on the drive wheel transmission shaft. A vehicle power transmission device is proposed.

  According to the invention described in claim 3, in addition to the configuration of claim 1 or claim 2, the speed increasing mechanism includes a drive helical gear provided on the output shaft, and a drive wheel transmission shaft. Proposed is a vehicle power transmission device including a driven helical gear provided, wherein the driving helical gear is fitted to the output shaft so as to be axially slidable and supported by a casing via a thrust bearing. .

  According to the invention described in claim 4, in addition to the configuration of claim 3, the drive helical gear is fitted to the output shaft so as not to be relatively rotatable and axially slidable. A vehicular power transmission device that can be coupled is proposed.

  According to a fifth aspect of the present invention, in addition to the configuration of the third aspect, the drive helical gear is splined to the output shaft so as not to rotate relative to the output shaft and to be axially slidable. A power transmission device is proposed.

  The eccentric disk 18 of the embodiment corresponds to the input side fulcrum of the present invention, the pin 19c of the embodiment corresponds to the output side fulcrum of the present invention, and the outer member 22 of the embodiment corresponds to the input member of the present invention. The angular ball bearings 40 and 41 of the embodiment correspond to the thrust bearing of the present invention, and the engine E of the embodiment corresponds to the drive source of the present invention.

  According to the configuration of the first aspect, the continuously variable transmission includes a plurality of transmission units juxtaposed in the axial direction of the input shaft and the output shaft, and when the input shaft connected to the drive source rotates, the input shaft rotates together with the input shaft. The connecting rod connected to the input side fulcrum reciprocates, and the connecting rod reciprocates the output fulcrum provided on the input member of the one-way clutch, so that the output shaft connected to the one-way clutch rotates intermittently. The output shaft driven at different phases by the transmission unit rotates continuously. When the amount of eccentricity of the input side fulcrum with respect to the input shaft is changed, the reciprocating stroke of the connecting rod is changed to change the rotation angle of the output shaft, thereby changing the gear ratio of the continuously variable transmission.

  Since it has a speed increasing mechanism that accelerates the rotation of the output shaft of the continuously variable transmission and transmits it to the drive wheel transmission shaft, the transmission ratio of the continuously variable transmission is set to a relatively large value while maintaining high transmission efficiency. By reducing the total gear ratio of the power transmission device including the continuously variable transmission and the speed increasing mechanism, the fuel consumption rate of the engine can be reduced.

  Also, if a speed increasing mechanism is provided upstream of the continuously variable transmission, the one-way clutch is engaged and disengaged per unit time compared to a speed increasing mechanism provided downstream of the continuously variable transmission. Since the number of times of response (response frequency) increases, it is necessary to set the friction damper of the one-way clutch strongly, and as a result, the friction of the one-way clutch increases. However, by providing a speed increasing mechanism on the downstream side of the continuously variable transmission, the required response frequency of the one-way clutch can be reduced, so the friction damper of the one-way clutch is set weaker to reduce the friction accordingly. can do.

  Further, since the speed increasing mechanism is provided on the downstream side of the continuously variable transmission, the output torque of the continuously variable transmission is reduced by the speed increasing mechanism and output to the drive wheel transmission shaft. Therefore, the torque fluctuation of the output shaft generated by the plurality of one-way clutches operating in order can be reduced by the speed increasing mechanism and output to the drive wheel transmission shaft.

  According to the second aspect of the present invention, the output shaft and the drive wheel transmission shaft are arranged on separate axes, and the differential gear is arranged on the drive wheel transmission shaft. Therefore, when the differential gear is arranged on the output shaft, Compared to this, the degree of freedom in setting the length of the drive wheel transmission shaft can be increased, and the lengths of the left and right drive wheel transmission shafts can be made uniform to improve riding comfort and handling.

  According to the third aspect of the present invention, since the speed increasing mechanism includes the drive helical gear provided on the output shaft and the driven helical gear provided on the drive wheel transmission shaft, the meshing rate is improved as compared with the case where the spur gear is used. The torque transmitted from the speed increasing mechanism to the drive wheel transmission shaft can be suppressed from fluctuating. At this time, the drive helical gear is fitted to the output shaft so as to be slidable in the axial direction and is supported by the casing via a thrust bearing. Therefore, the thrust force acting on the drive helical gear is supported by the casing and is not transmitted to the output shaft. Further, it is possible to prevent an increase in friction and abnormal wear of the one-way clutch provided on the output shaft.

  According to the fourth aspect of the present invention, the drive helical gear is fitted to the output shaft so as not to rotate relative to the output shaft and is slidable in the axial direction, and can be coupled to the output shaft by a dog clutch. The dog clutch is engaged to transmit the rotation of the output shaft to the drive helical gear while the dog clutch is disengaged to prevent the rotation of the drive helical gear during the reverse travel of the vehicle. Can be prevented from being transmitted back to the back.

  According to the fifth aspect of the present invention, the drive helical gear is spline-coupled to the output shaft so as not to rotate relative to the output shaft and is slidable in the axial direction, so that the rotation of the output shaft is transmitted to the drive helical gear via the spline. The thrust force acting on the shaft can be supported by the casing so that it is not transmitted to the output shaft.

The skeleton figure of the motive power apparatus for vehicle travel. [First Embodiment] FIG. 2 is a detailed view of part 2 of FIG. 1. [First Embodiment] FIG. 3 is a sectional view taken along line 3-3 in FIG. 2 (TOP state). [First Embodiment] FIG. 3 is a sectional view taken along line 3-3 in FIG. 2 (LOW state). [First Embodiment] The action explanatory view in the TOP state. [First Embodiment] The action explanatory view in the LOW state. [First Embodiment] FIG. 7 is a detailed view of part 7 of FIG. 1. [First Embodiment] The graph which shows the relationship between the gear ratio of a continuously variable transmission, and transmission efficiency. [First Embodiment] Explanatory drawing of the principle of torque amplitude reduction by a speed increasing mechanism. [First Embodiment] The graph which shows the relationship between the speed increase ratio of a speed increase mechanism, and output torque. [First Embodiment] The figure corresponding to the said FIG. [Second Embodiment] The graph which shows the relationship between the driving | running state of an engine, and a fuel consumption rate for every transmission gear ratio and vehicle speed of a continuously variable transmission. The graph which shows the relationship between the gear ratio of a continuously variable transmission, and the rocking | fluctuation angle of a one-way clutch. The graph which shows the relationship between the transmission efficiency with respect to the gear ratio of a continuously variable transmission, and the rocking | fluctuation angle of an output shaft. The graph which shows the relationship between the transmission gear ratio and transmission efficiency of a continuously variable transmission with different maximum transmission gear ratios.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, an input shaft 11 of a continuously variable transmission T is connected in series via a damper 32 to a crankshaft 31 of an engine E that is a driving source for driving an automobile. A speed change actuator A made of an electric motor for changing the speed ratio is connected in series to the end opposite to the engine E. The output shaft 12 arranged in parallel with the input shaft 11 of the continuously variable transmission T extends to the engine E side, and the rotation of the output shaft 12 is transmitted to the differential gear 35 via the dog clutch 33 and the speed increasing mechanism 34. Further, it is transmitted from the differential gear 35 to the left and right drive wheels W, W via drive wheel transmission shafts 36, 37 extending in the left-right direction. The speed increasing mechanism 34 is supported on the outer periphery of the output shaft 12 so as to be relatively rotatable, and can be coupled to the output shaft 12 by the dog clutch 33. The speed increasing mechanism 34 is formed with a smaller diameter than the drive helical gear 38 and a gear box of the differential gear 35. And a driven helical gear 39 that is fixedly mounted on the motor.

  Next, the structure of the continuously variable transmission T will be described with reference to FIGS.

  As shown in FIG. 2 and FIG. 3, the continuously variable transmission T is obtained by superimposing a plurality of (four in the embodiment) transmission units 10... Having the same structure in the axial direction. ... share the input shaft 11 and the output shaft 12.

  Hereinafter, the structure of one transmission unit 10 will be described as a representative. The input shaft 11 that is connected to the crankshaft 31 of the engine E and rotates passes through the hollow transmission shaft 14a of the transmission actuator A so as to be relatively rotatable. The rotor 14b of the speed change actuator A is fixed to the speed change shaft 14a, and the stator 14c is fixed to the casing. The transmission shaft 14 a of the transmission actuator A can rotate at the same speed as the input shaft 11 and can rotate relative to the input shaft 11 at a different speed.

  A first pinion 15 is fixed to the input shaft 11 passing through the transmission shaft 14 a of the transmission actuator A, and a crank-shaped carrier 16 is connected to the transmission shaft 14 a of the transmission actuator A so as to straddle the first pinion 15. The Two second pinions 17, 17 having the same diameter as the first pinion 15 are supported via pinion pins 16 a, 16 a at positions forming an equilateral triangle in cooperation with the first pinion 15, respectively. The first pinion 15 and the second pinions 17, 17 mesh with a ring gear 18 a formed eccentrically inside a disc-shaped eccentric disk 18. A ring portion 19 b provided at one end of the rod portion 19 a of the connecting rod 19 is fitted to the outer peripheral surface of the eccentric disk 18 via a ball bearing 20 so as to be relatively rotatable.

  A one-way clutch 21 provided on the outer periphery of the output shaft 12 is arranged inside the outer member 22 with a ring-shaped outer member 22 pivotally supported by a rod portion 19a of a connecting rod 19 via a pin 19c. 12, a roller disposed in a wedge-shaped space formed between an inner member 23 fixed to 12 and an arc surface on the inner periphery of the outer member 22 and a flat surface on the outer periphery of the inner member 23, and urged by springs 24. 25.

  As is apparent from FIG. 2, the four speed change units 10 share a crank-shaped carrier 16, but the phases of the eccentric disks 18 supported on the carrier 16 via the second pinions 17 and 17 are respectively different. The transmission unit 10 is different by 90 °. For example, in FIG. 2, the eccentric disk 18 of the leftmost transmission unit 10 is displaced upward in the figure with respect to the input shaft 11, and the eccentric disk 18 of the third transmission unit 10 from the left is illustrated with respect to the input shaft 11. The eccentric disks 18 and 18 of the second and fourth transmission units 10 and 10 from the left are positioned in the middle in the vertical direction.

  Next, the operation of one transmission unit 10 of the continuously variable transmission T will be described. When the transmission shaft 14a of the transmission actuator A4 is rotated relative to the input shaft 11, the carrier 16 rotates about the axis L1 of the input shaft 11. At this time, the center O of the carrier 16, that is, the center of the equilateral triangle formed by the first pinion 15 and the two second pinions 17, 17 rotates around the axis L 1 of the input shaft 11.

  3 and 5 show a state in which the center O of the carrier 16 is on the opposite side of the output shaft 12 with respect to the first pinion 15 (that is, the input shaft 11). The eccentricity ε (see FIG. 3) is maximized and the transmission ratio of the continuously variable transmission T is in the TOP state. 4 and 6 show a state in which the center O of the carrier 16 is on the same side as the output shaft 12 with respect to the first pinion 15 (that is, the input shaft 11). At this time, the eccentric disk 18 with respect to the input shaft 11 The eccentricity ε is minimized and the transmission ratio of the continuously variable transmission T is in the LOW state.

  In the TOP state shown in FIG. 5, when the input shaft 11 is rotated by the engine E and the transmission shaft 14a of the transmission actuator A is rotated at the same speed as the input shaft 11, the input shaft 11, the transmission shaft 14a, the carrier 16, With the one pinion 15, the two second pinions 17 and 17, and the eccentric disk 18 being integrated, the pinion 15 rotates eccentrically around the input shaft 11 (see arrow A). While rotating from FIG. 5A through FIG. 5B to the state of FIG. 5C, the ring portion 19b is supported on the outer periphery of the eccentric disk 18 via the ball bearing 20 so as to be relatively rotatable. The connecting rod 19 rotates the outer member 22 pivotally supported by a pin 19c at the tip of the rod portion 19a in the counterclockwise direction (see arrow B). 5A and 5C show both ends of rotation of the outer member 22 in the arrow B direction.

  When the outer member 22 rotates in the arrow B direction in this way, the rollers 25... Bite into the wedge-shaped space between the outer member 22 and the inner member 23 of the one-way clutch 21, and the rotation of the outer member 22 passes through the inner member 23. Therefore, the output shaft 12 rotates counterclockwise (see arrow C).

  When the input shaft 11 and the first pinion 15 further rotate, the eccentric disk 18 in which the ring gear 18a is engaged with the first pinion 15 and the second pinion 17, 17 rotates eccentrically in the counterclockwise direction (see arrow A). While rotating from the state shown in FIG. 5C to the state shown in FIG. 5A, the ring portion 19b is supported on the outer periphery of the eccentric disk 18 via the ball bearing 20 so as to be relatively rotatable. The connecting rod 19 rotates the outer member 22 pivotally supported by a pin 19c at the tip of the rod portion 19a in the clockwise direction (see arrow B ′). FIG. 5C and FIG. 5A show both ends of the rotation of the outer member 22 in the arrow B ′ direction.

  Thus, when the outer member 22 rotates in the direction of the arrow B ′, the rollers 25 are pushed out from the wedge-shaped space between the outer member 22 and the inner member 23 while compressing the springs 24. Slips with respect to the inner member 23 and the output shaft 12 does not rotate.

  As described above, when the outer member 22 reciprocates, the output shaft 12 rotates counterclockwise (see arrow C) only when the rotation direction of the outer member 22 is counterclockwise (see arrow B). The shaft 12 rotates intermittently.

  FIG. 6 shows the operation when the continuously variable transmission T is operated in the LOW state. At this time, since the position of the input shaft 11 coincides with the center of the eccentric disk 18, the eccentric amount ε of the eccentric disk 18 with respect to the input shaft 11 becomes zero. In this state, when the input shaft 11 is rotated by the engine E and the transmission shaft 14a of the transmission actuator A is rotated at the same speed as the input shaft 11, the input shaft 11, the transmission shaft 14a, the carrier 16, the first pinion 15, 2 In a state where the second pinions 17 and 17 and the eccentric disk 18 are integrated, the input pin 11 is rotated eccentrically in the counterclockwise direction (see arrow A). However, since the eccentric amount ε of the eccentric disk 18 is zero, the stroke of the reciprocating motion of the connecting rod 19 is also zero, and the output shaft 12 does not rotate.

  Accordingly, if the speed change actuator A is driven and the position of the carrier 16 is set between the TOP state of FIG. 3 and the LOW state of FIG. 4, the operation at an arbitrary speed ratio between the zero speed ratio and the predetermined speed ratio can be performed. It becomes possible.

  In the continuously variable transmission T, the phases of the eccentric disks 18 of the four transmission units 10 arranged in parallel are shifted from each other by 90 °, so that the four transmission units 10 alternately transmit the driving force. In other words, any one of the four one-way clutches 21 is always in an engaged state, so that the output shaft 12 can be continuously rotated.

  Next, the structures of the dog clutch 33 and the speed increasing mechanism 34 will be described with reference to FIG.

  The speed increasing mechanism 34 includes a drive helical gear 38 supported on the outer periphery of the output shaft 12 so as to be relatively rotatable, and a driven helical gear 39 fixed to the gear box of the differential gear 35. The driven helical gear 39 is used for preventing the pulsation of torque transmission by improving the gear tooth meshing ratio, and has a large diameter drive so as to increase the rotational speed of the output shaft 12 and transmit it to the differential gear 35. The number of teeth of the helical gear 38 is set to be larger than the number of teeth of the small-diameter driven helical gear 39 (see FIG. 1).

  Since the helical gears mesh with each other at an angle when transmitting torque, an axial thrust force is generated. If this thrust force is transmitted to the output shaft 12, the one-way clutches 21 provided on the output shaft 12 may be abnormally worn or the friction may increase. 38 is floating supported by the output shaft 12 so as to be relatively rotatable and slidable in the axial direction, and is rotatably supported by the casing 42 via angular ball bearings 40 and 41 capable of supporting both radial force and thrust force. Therefore, since the thrust force acting on the drive helical gear 38 is transmitted to and supported by the casing 42 and is not transmitted to the output shaft 12, it is possible to reliably prevent abnormal wear of the one-way clutch 21 and increase in friction due to the thrust force. can do.

  The output shaft 12 is rotatably supported on the casing 42 via a pair of ball bearings 43, 44 on both axial sides of the drive helical gear 38, and the dog clutch 33 is interposed between the right angular ball bearing 41 and the right ball bearing 44. Is placed. The dog clutch 33 is formed with a spline 38b formed on the outer periphery of a boss 38a extending to the right side from the drive helical gear 38, a spline 12a formed on the outer periphery of the output shaft 12, and a spline 45a that can be engaged with both the splines 38b and 12a simultaneously. And a fork 46 that fits into the fork groove 45b of the sleeve 45 and drives the sleeve 45 in the axial direction. Accordingly, in FIG. 7, when the sleeve 45 is moved to the left by the fork 46, the drive helical gear 38 is coupled to the output shaft 12, and when the sleeve 45 is moved to the right by the fork 46, the drive helical gear 38 is disconnected from the output shaft 12.

  A reverse gear 48 fixed to the motor shaft 47 of the reverse drive electric motor M meshes with a driven helical gear 39 fixed to the gear box of the differential gear 35.

  Next, the operation of the embodiment of the present invention having the above configuration will be described.

  In a state where the dog clutch 33 is engaged and the drive helical gear 38 is coupled to the output shaft 12, the driving force of the engine E is input from the crankshaft 31 to the input shaft 11 via the damper 32 and is shifted by the continuously variable transmission T. And output to the output shaft 12. The rotation of the output shaft 12 is transmitted from the dog clutch 33 to the drive wheels W and W via the drive helical gear 38, the driven helical gear 39, the differential gear 35, and the left and right drive wheel transmission shafts 36 and 37, thereby causing the vehicle to travel forward. While the vehicle is stopped, the output shaft 12 stops rotating by setting the eccentricity ε of the continuously variable transmission T to zero, so that the idling operation of the engine E can be performed without disengaging the dog clutch 33.

  During reverse travel of the vehicle, the dog clutch 33 is disengaged and the electric motor M is driven with the drive helical gear 38 disconnected from the output shaft 12, and the rotation of the motor shaft 47 is transferred to the driven helical gear 39 via the reverse gear 48. Just communicate. If the electric motor M is driven in the opposite direction to the reverse travel, the forward travel by the electric motor M and the assist of the driving force of the engine E by the electric motor M can be performed.

  When the vehicle travels backward with the dog clutch 33 engaged, the rotation of the drive wheels W and W is transmitted back to the output shaft 12, but the continuously variable transmission T has a driving force from the output shaft 12 side to the input shaft 11 side. Since the one-way clutches 21 are continuously engaged, the connecting rods 19 may be damaged. However, in the present embodiment, the above problem can be solved by disengaging the dog clutch 33 when the vehicle is traveling backward.

  In the present embodiment, the rotation of the output shaft 12 is transmitted to the differential gear 35 in a state of being accelerated through the speed increasing mechanism 34 including the driving helical gear 38 and the driven helical gear 29. Can be achieved.

  In FIG. 8, the thick broken line is a characteristic line showing the relationship between the single transmission ratio and the transmission efficiency of the continuously variable transmission T of the present invention, and the thick solid line is a combination of the speed increasing mechanism 34 with the continuously variable transmission T of the present invention. This is the total characteristic line of the food. Compared to a single characteristic line of the thick broken line continuously variable transmission T, a total characteristic line of the thick continuous line continuously variable transmission T and the speed increasing mechanism 34 is shifted to the lower side and right side in the figure. The total characteristic line is shifted downward because the provision of the speed increasing mechanism 34 increases the friction and lowers the transmission efficiency. The total characteristic line is shifted to the right because the speed ratio is reduced by providing the speed increasing mechanism 34.

  Thus, by combining the speed increasing mechanism 34 with the continuously variable transmission T, the total transmission efficiency slightly decreases in the region where the gear ratio is about 5 or more, but increases in the region where the gear ratio is less than about 5. Can be made. This is possible because the continuously variable transmission T of the present invention can obtain a high gear ratio, and the transmission efficiency is maintained at a substantially constant high value in the region of the high gear ratio.

  In FIG. 8, the thin broken line is a characteristic line showing the relationship between the transmission ratio and transmission efficiency of a single belt type continuously variable transmission, and the thin solid line is the total characteristic of the belt type continuously variable transmission combined with a speed increasing mechanism. Line. However, it is difficult to obtain a high gear ratio with a belt-type continuously variable transmission, and transmission efficiency decreases in the high gear ratio region. Therefore, when a speed increasing mechanism is combined with a belt-type continuously variable transmission (see thin solid line) ), It is not possible to obtain a high gear ratio required to generate torque at the time of starting, which may make it difficult to start smoothly, and engine E may stall depending on the generated torque of engine E there is a possibility.

  As described above, according to the present embodiment, by combining the continuously variable transmission T and the speed increasing mechanism 34, the minimum gear ratio can be reduced to, for example, 2 or less while maintaining high transmission efficiency. Thereby, the driving | running state of the vehicle in FIG. 12 can be moved to the point b from the point a, and a fuel consumption rate can be reduced.

  As shown in FIG. 14, the high transmission efficiency portion of the continuously variable transmission T is a region where the gear ratio is 6 to ∞, so that the reduction of the fuel consumption rate described in FIG. In order to obtain the gear ratio, the continuously variable transmission T is used in the region where the gear ratio is 6 to ∞, and the speed increasing ratio of the speed increasing mechanism 34 is set to 4 so that the speed ratio = 1.5 is obtained. You can do it. On the other hand, if the speed increasing ratio of the speed increasing mechanism 34 is increased, the friction also increases. Therefore, it is desirable to keep the speed increasing ratio small. However, if the speed increasing ratio is kept small, the fuel consumption rate reducing effect described with reference to FIG. Therefore, the minimum value of the speed increasing ratio is about 1.3. Therefore, it is desirable that the speed increasing ratio range of the speed increasing mechanism 34 is about 1.3 to 4.

  Assuming that the average torque transmitted from the engine E to the drive wheels W and W is the same, the output torque varies when the speed increasing mechanism 34 is provided, compared to when the speed increasing mechanism 34 is not provided. The amplitude to be performed can be kept small. Hereinafter, the reason will be described with reference to FIG.

  FIG. 9A shows the output torque of one one-way clutch 21 of the continuously variable transmission T with respect to the rotation angle of the output shaft 12, and the broken line indicates the case where the speed increasing mechanism 34 is not provided (the speed increasing ratio is 1), the solid line corresponds to the case where the speed increasing mechanism 34 is provided (when the speed increasing ratio is 1 or more). From the figure, it can be seen that when the speed increasing mechanism 34 is provided, the peak torque of the output torque of one one-way clutch 21 of the continuously variable transmission T is larger and the angle of torque transmission is larger. I understand.

  The reason is that the magnitude of the transmission torque changes according to the angle at which the outer ring is twisted with respect to the inner ring from the state in which the torque is transmitted by the roller in the mechanism in which the one-way clutch 21 transmits the torque. This is because when the transmission torque is large, the twisted angle becomes large.

  FIG. 9B shows the output torque of the speed increasing mechanism 34 with respect to the rotation angle of the output shaft 12. The broken line is the case where the speed increasing mechanism 34 is not provided (when the speed increasing ratio is 1). In this case, torque reduction is not performed in the speed increasing mechanism 34, and thus the same as the broken line in FIG. Output torque is set. On the other hand, the solid line shows the case where the speed increasing mechanism 34 is provided (when the speed increasing ratio is 1 or more). In this case, assuming that the speed increasing ratio in the speed increasing mechanism 34 is n, the output torque is as shown in FIG. Compared to the solid line in (A), it decreases to 1 / n.

  FIG. 9C is a composite of the graph of FIG. 9B so as to correspond to a plurality of one-way clutches 21 that are sequentially engaged with a time difference. As is clear from the figure, when the speed increasing mechanism 34 shown by the solid line is provided, the peak torque of the output torque transmitted by one one-way clutch 21 is reduced, and the one-way clutch 21 that is engaged in the front and rear direction. Therefore, the amplitude A2 of the output torque is smaller than the amplitude A1 when the speed increasing mechanism 34 indicated by the broken line is not provided.

  FIG. 10 shows the amplitude of the output torque of the speed increasing mechanism 34 when the speed increasing ratio of the speed increasing mechanism 34 is changed. The speed ratio of the continuously variable transmission T is in the top drive state (the speed ratio is small). State) and in the case where the gear ratio of the continuously variable transmission T is in an underdrive state (a state in which the gear ratio is large), the amplitude of the output torque of the speed increasing mechanism 34 decreases as the speed increasing ratio increases. I understand.

  As described above, when the speed increasing ratio of the speed increasing mechanism 34 is increased, the amplitude of the output torque of the speed increasing mechanism 34 can be decreased. However, in order to make the output torque of the speed increasing mechanism 34 constant, the speed increasing mechanism Therefore, it is necessary to increase the speed ratio (reduction ratio) of the continuously variable transmission T by an amount corresponding to the increase of the speed increase ratio 34. When the transmission ratio (reduction ratio) of the continuously variable transmission T increases, the output torque increases, so that the torque to be transmitted by the one-way clutch 21... Increases and the one-way clutch 21. It is difficult to increase the speed increasing ratio of the speed increasing mechanism 34 in a dark manner. Therefore, considering that the amplitude of the output torque of the speed increasing mechanism 34 is reduced and the one-way clutch 21 is increased in size, the speed increasing ratio of the speed increasing mechanism 34 is preferably about 1.5 to 3. It is done.

  By the way, assuming that the rotation speed of the output shaft 12 is the same, if the speed increasing mechanism 34 is provided on the upstream side (engine E side) of the continuously variable transmission T, on the downstream side of the continuously variable transmission T. Compared with the case where the speed increasing mechanism 34 is provided, the number of times the one-way clutch 21 is engaged and disengaged per unit time is increased. That is, the one-way clutch 21 needs to be engaged and disengaged at short time intervals, and a high response frequency is required. In order to satisfy this requirement, the springs 25 (see FIGS. 3 and 4) for urging the rollers 25 of the one-way clutch 21 in a direction to be engaged with the wedge surface formed between the outer member 23 and the inner member 23. It is necessary to set the resilient force strongly, and as a result, the friction of the one-way clutch 21 increases.

  However, according to the present embodiment, since the speed increasing mechanism 34 is provided on the downstream side of the continuously variable transmission T, the required response frequency of the one-way clutch 21 can be reduced. It is possible to reduce the friction by setting the elastic force of the lens to be weak.

  As shown by a chain line in FIG. 1, if the speed increasing mechanism 34 is abolished and the drive wheel transmission shafts 36 and 37 are connected to both ends of the output shaft 12 of the continuously variable transmission T, it is connected to the left end of the output shaft 12. The length of the left driving wheel transmission shaft 36 is extremely shorter than the length of the right driving wheel transmission shaft 37 connected to the right side of the output shaft 12, and the left and right driving wheel transmission shafts 36, 37 There is a possibility that the ride comfort and the maneuverability are lowered due to the unbalance of the length.

  However, according to the present embodiment, since the drive wheel transmission shafts 36 and 37 are arranged on a separate shaft from the output shaft 12 of the continuously variable transmission T, the lengths of the left and right drive wheel transmission shafts 36 and 37 are substantially reduced. Evenly, it is possible to prevent a decrease in ride comfort and maneuverability.

  Next, a second embodiment of the present invention will be described with reference to FIG.

  In the first embodiment, the speed increasing mechanism 34 is composed of a drive helical gear 38 and a driven helical gear 39. In the second embodiment, the speed increasing mechanism 34 is added to the drive helical gear 38 and the driven helical gear 39. A planetary gear mechanism 49 is provided.

  The planetary gear mechanism 49 includes a sun gear 50 as an output member, a carrier 51 as an input member, a ring gear 52 as a fixed member, and a plurality of gears that are rotatably supported by the carrier 51 and simultaneously mesh with the sun gear 50 and the ring gear 52. Pinions 53 are provided. The sun gear 50 is fixed to the boss portion of the drive helical gear 38, the carrier 51 is supported by the casing 42 via the ball bearing 54, and the ring gear 52 is fixed to the casing 42. The dog clutch 33 can couple the carrier 51 and the output shaft 12.

  Therefore, when the dog clutch 33 is engaged, the rotation of the output shaft 12 is accelerated through the dog clutch 33, the carrier 51, the pinion 53... And the sun gear 50 and transmitted to the drive helical gear 38, and from there through the driven helical gear 39. The speed is further increased and transmitted to the differential gear 35.

  According to the present embodiment, the planetary gear mechanism 49 increases the first speed, and the driving helical gear 38 and the driven helical gear 39 increase the second speed. Therefore, a large speed ratio can be easily secured. Can do. In addition, the diameter of the driven helical gear 39 cannot be made sufficiently small due to the size of the differential gear 35, so that even if the driving helical gear 38 and the driven helical gear 39 cannot increase the speed, the planetary gear mechanism 49 can increase the required speed. A speed ratio can be secured.

  Also according to the second embodiment, it is possible to achieve the same operational effects as those of the first embodiment described above.

  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, the drive source of the present invention is not limited to the engine E of the embodiment, and may be another drive source such as an electric motor.

  In the embodiment, the angular ball bearings 40 and 41 are employed as thrust bearings for supporting the thrust force acting on the driving helical gear 38, but any type of thrust bearing can be employed.

  In the embodiment, the drive helical gear 38 is supported on the casing 42 by a pair of angular ball bearings 40, 41. However, the rotational direction of the engine E is fixed, and the direction of the thrust force acting on the drive helical gear 38 is constant. Therefore, only the bearing on the side that receives the thrust force of the drive helical gear 38 may be constituted by a thrust bearing.

  When the dog clutch 33 is not provided, the drive helical gear 38 is supported on the casing 42 via a thrust bearing while the drive helical gear 38 is supported by the spline so as not to rotate relative to the output shaft 12 and to be axially slidable. Thus, it is possible to prevent the thrust force from being transmitted to the output shaft 12.

10 Transmission unit 11 Input shaft 12 Output shaft 18 Eccentric disc (input fulcrum)
19 Connecting rod 19c Pin (Output side fulcrum)
21 One-way clutch 22 Outer member (input member)
33 dog clutch 34 speed increasing mechanism 35 differential gear 36 driving wheel transmission shaft 37 driving wheel transmission shaft 38 driving helical gear 39 driven helical gear 40 angular ball bearing (thrust bearing)
41 Angular ball bearing (thrust bearing)
42 Casing E Engine (drive source)
L1 Input shaft axis T Continuously variable transmission W Drive wheel ε Eccentricity

Claims (5)

A continuously variable transmission (T) that shifts and transmits the rotation of the input shaft (11) connected to the drive source (E) to the output shaft (12) includes the input shaft (11) and the output shaft (12). A plurality of transmission units (10) juxtaposed in the axial direction of
Each of the plurality of transmission units (10)
An input side fulcrum (18) that is variable in eccentricity (ε) from the axis (L1) of the input shaft (11) and rotates together with the input shaft (11);
A one-way clutch (21) connected to the output shaft (12);
An output fulcrum (19c) provided on an input member (22) of the one-way clutch (21);
A connecting rod (19) reciprocatingly connected at both ends to the input side fulcrum (18) and the output side fulcrum (19c);
A drive wheel transmission shaft (36, 37) for transmitting rotation of the output shaft (12) to a drive wheel (W),
A vehicle power transmission device comprising a speed increasing mechanism (34) for increasing the speed of rotation of the output shaft (12) and transmitting it to the drive wheel transmission shafts (36, 37).   The output shaft (12) and the drive wheel transmission shaft (36, 37) are disposed on different shafts, and a differential gear (35) is disposed on the drive wheel transmission shaft (36, 37). The vehicle power transmission device according to claim 1.   The speed increasing mechanism (34) includes a drive helical gear (38) provided on the output shaft (12) and a driven helical gear (39) provided on the drive wheel transmission shaft (36, 37), The drive helical gear (38) is fitted to the output shaft (12) so as to be slidable in the axial direction, and is supported on the casing (42) of the continuously variable transmission (T) via thrust bearings (40, 41). The power transmission device for a vehicle according to claim 1 or 2, wherein the power transmission device is for a vehicle.   The drive helical gear (38) is fitted to the output shaft (12) so as not to be relatively rotatable and axially slidable, and can be coupled to the output shaft (12) by a dog clutch (33). The vehicle power transmission device according to claim 3.   The power transmission device for a vehicle according to claim 3, wherein the drive helical gear (38) is splined to the output shaft (12) so as not to rotate relative to the output shaft and to be axially slidable.

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