JP2016148407A - Automatic transmission for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a an automatic transmission for a vehicle which can prevent an inclination of a sun gear caused by a gearing reaction force transmitted to a start gear, in the automatic transmission for the vehicle having a planetary gear device and the start gear into which power from the sun gear of the planetary gear device is inputted.SOLUTION: Since backlash which is larger than the displacement of a start gear 36 generated by an inclination of the start gear 36 by a gearing reaction force transmitted to the start gear 36 is generated at a spline fitting part 78 between a sun gear 30s and the start gear 36, even if a small-diameter gear 36 is inclined due to the transmission of the gearing reaction force to the small-diameter gear 36, the deterioration of vibration and noise caused by the deterioration of an engagement state of a planetary gear device 30 can be suppressed without causing an inclination of the sun gear 30s.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an automatic transmission for a vehicle, and particularly to reduction of vibration and noise generated during power transmission.

  2. Description of the Related Art Automatic transmissions with various structures have been realized as automatic transmissions for vehicles that change the speed of rotation of a power source and transmit it to an output shaft. For example, in Patent Document 1, a power transmission path by a gear train 23 (gear train) and a power transmission mechanism by a continuously variable transmission 1 are provided between an engine 2 that functions as a power source and an output shaft 22. A structure provided in parallel is disclosed. For example, in FIG. 10 of Patent Document 1, as a power transmission path by the gear train 23, a forward / reverse switching mechanism 10 constituted by a planetary gear device, a drive gear 25, a counter driven gear 26, a counter drive gear 27, and a driven gear 28 are used. What is composed is disclosed. The forward / reverse switching mechanism 10 includes a carrier to which power from a power source is transmitted, a ring gear provided with a brake mechanism B, and a sun gear that outputs power input to the carrier. The power output from the sun gear is configured to be transmitted to the drive gear 25.

International Publication No. 2013/176208

  Incidentally, in the configuration of Patent Document 1 described above, the sun gear and the drive gear 25 are configured to have an integral structure. If comprised in this way, when the drive gear 25 inclines by the meshing reaction force from the drive wheel side, a sun gear will also incline similarly. At this time, the meshing state of the planetary gear device may deteriorate, and vibration and noise may increase.

  The present invention has been made in the background of the above circumstances, and the object thereof is to include a planetary gear device and a starting gear to which power output from the sun gear of the planetary gear device is input. An object of the present invention is to provide an automatic transmission for a vehicle in which the sun gear is prevented from being tilted by a meshing reaction force transmitted to a starting gear.

  In order to achieve the above object, the gist of the first invention includes (a) a carrier to which power from a power source is input, a sun gear to which power input to the carrier is output, and a ring gear. In an automatic transmission for a vehicle provided with a planetary gear unit configured and a starting gear to which power output from the sun gear is input, (b) the sun gear and the starting gear are connected by spline fitting. (C) The spline fitting portion between the sun gear and the starting gear is based on the displacement of the starting gear due to the inclination of the starting gear due to the meshing reaction force transmitted from the gear meshing with the starting gear to the starting gear. A large backlash is formed.

  In this way, since the meshing reaction force is transmitted to the starting gear and the starting gear is tilted, the sun gear is not tilted due to backlash, so that vibrations and noise caused by deterioration of the meshing state of the planetary gear device are prevented. Deterioration can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a skeleton diagram for explaining a schematic configuration of a vehicle drive device according to an embodiment of the present invention. It is sectional drawing explaining the structure around a forward / reverse switching device of FIG. 1 and a small diameter gear. FIG. 3 shows the contact of the sun gear with the pinion gear when the sun gear of FIG. 2 is tilted. It is a figure which shows the relationship between the tooth | gear contact of a sun gear, and tooth root stress. It is a figure which shows the relationship between the tooth contact of a sun gear, and a meshing transmission error.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios, shapes, and the like of the respective parts are not necessarily drawn accurately.

  FIG. 1 is a skeleton diagram for explaining a schematic configuration of a vehicle drive device 12 (hereinafter referred to as drive device 12) according to an embodiment of the present invention. The drive device 12 includes, for example, an engine 14 used as a driving power source, a torque converter 16 as a fluid transmission device, a forward / reverse switching device 18, and a belt-type continuously variable transmission mechanism 20 (hereinafter referred to as a continuously variable transmission mechanism). 20), a gear mechanism 22, an output shaft 25 on which an output gear 24 capable of transmitting power to the drive wheels 70 is formed, and a differential gear 64. In the drive device 12, an automatic transmission 23 (automatic transmission for a vehicle) configured such that a continuously variable transmission mechanism 20 and a gear mechanism 22 are provided in parallel between a turbine shaft 26 and an output shaft 25. Is provided. As a result, the power output from the engine 14 is transmitted to the turbine shaft 26 via the torque converter 16, and this power is transmitted from the turbine shaft 26 to the output shaft 25 via the continuously variable transmission mechanism 20. A second transmission path in which power output from the engine 14 is transmitted to the turbine shaft 26 via the torque converter 16, and this power is transmitted from the turbine shaft 26 to the output shaft 25 via the gear mechanism 22. Is formed, and the first transmission path and the second transmission path are selectively switched according to the traveling state of the vehicle.

  The engine 14 functions as a power source, and is constituted by an internal combustion engine such as a gasoline engine or a diesel engine. The torque converter 16 includes a pump impeller 16p connected to the crankshaft of the engine 14 and a turbine impeller 16t connected to the forward / reverse switching device 18 via a turbine shaft 26 corresponding to an output side member of the torque converter 16. And power transmission is performed via a fluid. Further, a lockup clutch 28 is provided between the pump impeller 16p and the turbine impeller 16t, and the pump impeller 16p and the turbine impeller 16t rotate as a unit when the lockup clutch 28 is completely engaged. Be made.

  The forward / reverse switching device 18 is composed mainly of a forward clutch Ca, a reverse brake B, and a double pinion planetary gear device 30, and a carrier 30 c is a turbine shaft 26 of the torque converter 16 and a continuously variable transmission mechanism 20. The ring gear 30r is selectively connected to the housing 34 as a non-rotating member via the reverse brake B, and the sun gear 30s is connected to the small diameter gear 36. Further, the sun gear 30s and the carrier 30c are selectively connected via the forward clutch Ca. The forward clutch Ca and the reverse brake B correspond to a connection / disconnection device, and both are hydraulic friction engagement devices frictionally engaged by a hydraulic actuator. Therefore, when the sun gear 30s and the carrier 30c are connected, the power from the engine 12 is input to the carrier 30c, and the power input to the carrier 30c is input from the sun gear 30s to the small diameter gear 36. The small diameter gear 36 corresponds to the starting gear of the present invention.

  The sun gear 30 s of the planetary gear device 30 is connected to a small-diameter gear 36 that constitutes the gear mechanism 22. The gear mechanism 22 includes the small-diameter gear 36 and a large-diameter gear 40 that is provided on the first counter shaft 38 so as not to be relatively rotatable. An idler gear 42 is provided around the same rotational axis as the first counter shaft 38 so as to be rotatable relative to the first counter shaft 38. A meshing clutch D is provided between the first counter shaft 38 and the idler gear 42 to selectively connect and disconnect them. The meshing clutch D is engageable with the first gear 48 formed on the first counter shaft 38, the second gear 50 formed on the idler gear 42, and the first gear 48 and the second gear 50 (engagement). And a hub sleeve 61 on which spline teeth are formed, and the hub sleeve 61 is engaged with the first gear 48 and the second gear 50, whereby the first counter The shaft 38 and the idler gear 42 are connected. The meshing clutch D further includes a synchromesh mechanism S as a synchronizing mechanism that synchronizes rotation when the first gear 48 and the second gear 50 are engaged. The large-diameter gear 40 corresponds to a gear that meshes with the starting gear of the present invention.

  The idler gear 42 is meshed with an input gear 52 having a larger diameter than the idler gear 42. The input gear 52 is provided so as not to rotate relative to the output shaft 25 arranged on a rotation axis common to a rotation axis of a secondary pulley 56 described later of the continuously variable transmission mechanism 20. The output shaft 25 is disposed so as to be rotatable around the rotation axis, and the input gear 52 and the output gear 24 are provided so as not to be relatively rotatable. Further, a forward clutch Ca, a reverse brake B, and a meshing clutch D are provided on the second transmission path through which the power of the engine 14 is transmitted from the turbine shaft 26 to the output shaft 25 via the gear mechanism 22. ing.

  The continuously variable transmission mechanism 20 is an input side member that is provided on a torque transmission path between the turbine shaft 26 that functions as an input shaft and the output shaft 25 and is connected to the turbine shaft 26 via a primary shaft 32. A primary pulley 54 (variable pulley 54) having a variable diameter, and a secondary pulley 56 (variable pulley 56) having a variable effective diameter, which is an output side member connected to the output shaft 25 via a belt traveling clutch Cb described later. A transmission belt 58 wound between the pair of pulleys 54 and 56 is provided, and power is transmitted through a frictional force between the pair of variable pulleys 54 and 56 and the transmission belt 58.

  The primary pulley 54 is a fixed sheave 54a as an input-side fixed rotating body fixed to the primary shaft 32, and an input-side movable rotation provided so as not to be rotatable relative to the primary shaft 32 and movable in the axial direction. A movable sheave 54b as a body and a primary hydraulic actuator 54c that generates a thrust for moving the movable sheave 54b in order to change the width of the V-groove therebetween are provided. The secondary pulley 56 includes a fixed sheave 56a serving as an output-side fixed rotating body, and a movable sheave serving as an output-side movable rotating body provided so as not to rotate relative to the fixed sheave 56a and to be movable in the axial direction. 56b and a secondary hydraulic actuator 56c that generates thrust for moving the movable sheave 56b to change the V groove width therebetween.

  By changing the V groove width of the pair of variable pulleys 54 and 56 and changing the engagement diameter (effective diameter) of the transmission belt 58, the actual transmission gear ratio (gear ratio) γ (= primary rotational speed Nin / secondary rotational speed). The speed Nout) is continuously changed. For example, when the V groove width of the primary pulley 54 is reduced, the speed ratio γ is reduced. That is, the continuously variable transmission mechanism 20 is upshifted. Further, when the V groove width of the primary pulley 54 is increased, the speed ratio γ is increased. That is, the continuously variable transmission mechanism 20 is downshifted.

  Further, between the continuously variable transmission mechanism 20 and the output shaft 25, a belt traveling clutch Cb that selectively connects and disconnects between these is inserted, and the belt traveling clutch Cb is engaged. Thus, a first transmission path through which the power of the engine 14 is transmitted to the output shaft 25 via the turbine shaft 26 and the continuously variable transmission mechanism 20 is formed. Further, when the belt traveling clutch Cb is released, the first transmission path is interrupted and power is not transmitted to the output shaft 25 via the continuously variable transmission mechanism 20.

  The output gear 24 is meshed with a large-diameter gear 62 that is fixed to the second counter shaft 60. The second counter shaft 60 is provided with a small-diameter gear 68 that meshes with the large-diameter gear 62 and the differential ring gear 66 of the differential gear 64. The differential gear 64 is composed of a differential mechanism, and transmits the power input from the differential ring gear 66 to the left and right drive wheels 70L and 70R while giving an appropriate rotational speed difference to the left and right drive wheels 70L and 70R. Since the differential gear 64 is a known technique, a detailed description thereof is omitted.

  In the drive device 12 configured as described above, when the belt travel clutch Cb is engaged, forward travel is performed by the first transmission path through which power is transmitted via the continuously variable transmission mechanism 20, and forward travel is performed. When the clutch Ca and the meshing clutch D are engaged, the forward travel is executed by the second transmission path through which power is transmitted via the gear mechanism 22. Further, when the rear wheel brake B and the meshing clutch D are engaged, the reverse travel is executed by the second path through which power is transmitted via the gear mechanism 22.

  FIG. 2 is a cross-sectional view illustrating the structure around the forward / reverse switching device 18 and the small-diameter gear 36 of FIG. The forward / reverse switching device 18 and the small-diameter gear 36 are disposed on the outer peripheral side of the turbine shaft 26 that rotates about the rotation axis C1. The forward / reverse switching device 18 mainly includes a planetary gear device 30, a forward clutch Ca, and a rear wheel brake B. The planetary gear device 30 is a double pinion type planetary gear device, and includes a sun gear 30s, a ring gear 30r concentrically arranged with the sun gear 30s, and a pair of pinion gears P1 and P2 that mesh with the sun gear 30s and the ring gear 30r, respectively. The carrier 30c holds the pinion gears P1 and P2 so that they can rotate and revolve.

  The sun gear 30s is formed in an annular shape and is disposed so as to be rotatable around the rotation axis C1. Further, outer peripheral teeth that mesh with the pinion gear P1 (not shown in FIG. 2) are formed on the outer peripheral surface of the sun gear 30s. A small diameter gear 36 is connected to the engine 14 side (right side in FIG. 2) of the sun gear 30s in the rotation axis C1 direction.

  The ring gear 30r is formed in an annular shape and is disposed so as to be rotatable around the rotation axis C1. Inner peripheral teeth that mesh with the pinion gear P2 are formed on the inner peripheral surface of the ring gear 30r. Although not illustrated in FIG. 2, the outer peripheral side of the ring gear 30 r is configured to be selectively connectable to the housing 34 that is a non-rotating member via the brake mechanism B.

  The pinion gear P1 (not shown in FIG. 2) and the pinion gear P2 mesh with each other and are held rotatably (rotatable) around the carrier pin 72 held at both ends by the carrier 30c. The pinion gear P1 is meshed with the outer peripheral teeth of the sun gear 30s, and the pinion gear P2 is meshed with the inner peripheral teeth of the ring gear 30r.

  The carrier 30c holds the pinion gears P1 and P2 such that they can rotate and revolve. Further, the inner peripheral end portion of the carrier 30c on the continuously variable transmission 20 side (left side in the drawing) in the direction of the axis line C1 is connected to a flange portion 26a extending in the radial direction from the input shaft 26. Accordingly, the carrier 30c rotates integrally with the input shaft 26. A cylindrical portion 74 extending toward the engine 14 side in the direction of the rotational axis C1 is formed on the outer peripheral portion of the carrier 30c on the engine 14 side (right side in the drawing) in the direction of the rotational axis C1. On the outer peripheral portion of the cylindrical portion 74, an inner friction plate of a friction engagement element constituting the forward clutch Ca is fitted so as not to be relatively rotatable.

  The engine 14 side of the sun gear 30s in the direction of the rotation axis C1 is connected to the small-diameter gear 36 so that power can be transmitted by spline fitting. The small-diameter gear 36 is formed in a cylindrical shape, and outer peripheral teeth 36a that mesh with the large-diameter gear 40 are formed on the outer peripheral portion on the engine 14 side in the direction of the rotation axis C1. The small-diameter gear 36 is supported by a ball bearing 76 fitted to the housing 34 so as to be rotatable around the rotation axis C1.

  Here, in the spline fitting portion 78 that is a connecting portion between the sun gear 30s and the small diameter gear 36, the spline teeth 80 (outer peripheral teeth 80) of the sun gear 30s and the spline teeth 82 (inner peripheral teeth 82) of the small diameter gear 36 are: It is fastened with loose fitting. Specifically, even if the small-diameter gear 36 is tilted by the meshing reaction force transmitted to the outer peripheral teeth 36a of the small-diameter gear 36, the spline teeth 80 of the sun gear 30s and the small-diameter gear are prevented from tilting due to the tilt. In the spline fitting portion 78 with the 36 spline teeth 82, a backlash (gap) larger than the displacement of the spline teeth 82 of the small diameter gear 36 due to the inclination of the small diameter gear 36 due to the meshing reaction force transmitted to the small diameter gear 36 is formed. Has been. That is, since power in the rotational direction is transmitted during power transmission, the radial play (gap) of the spline fitting portion 78 formed between the spline teeth 82 of the small diameter gear 36 and the spline teeth 80 of the sun gear 30s. However, they are separated from the displacement of the spline teeth 82 due to the inclination of the small diameter gear 36.

  Here, the meshing reaction force is the mutual gears 36, 40 transmitted from the large diameter gear 40 meshing with the small diameter gear 36 to the small diameter gear 36 during power transmission between the small diameter gear 36 and the large diameter gear 40. This is the force acting in the direction in which the distance between the rotation axes increases. When this meshing reaction force acts, one end of the small diameter gear 36 is urged in the radial direction, so that the small diameter gear 36 is inclined. That is, the rotation axis of the small diameter gear 36 is eccentric with respect to the rotation axis of the turbine shaft 26.

  Accordingly, even if the meshing reaction force from the drive wheel 70 side is transmitted to the outer peripheral teeth 36a of the small diameter gear 36 and the small diameter gear 36 tilts, the sun gear 30s only displaces (moves) within the range of the play. The sun gear 30s is restrained from being tilted under the influence of the meshing reaction force. Therefore, the meshing state of the planetary gear device 30 due to the inclination of the sun gear 30s is not deteriorated, and the reduction of the gear strength due to the deterioration of the meshing state, the vibration and noise due to the deterioration of the meshing transmission error, and the reduction of the meshing efficiency are suppressed. .

  FIG. 3 shows a tooth contact that is a contact surface of the sun gear 30s with the pinion gear P1 when the sun gear 30s is tilted. FIG. 3 (a) shows the tooth contact of the present embodiment (good posture) when the sun gear 30s is not tilted, and FIG. 3 (b) shows the teeth when the sun gear 30s is tilted (bad posture) as a comparison target. It shows a hit. In FIG. 3, the mesh portion corresponds to the tooth contact with the pinion gear P1, that is, the contact surface with the pinion gear P1. As shown in FIG. 3 (a), when the sun gear 30s is not tilted, the tooth surface of the outer peripheral teeth of the sun gear 30 extends over substantially the entire tooth width direction and the tooth-brushing direction from the start of meshing to the end of meshing. In contact with the pinion gear P1 (good tooth contact). On the other hand, when the sun gear 30s is inclined, as shown in FIG. 3B, the contact surface is biased in the tooth width direction, and the tooth contact is significantly smaller than that in FIG. ).

  FIG. 4 shows the relationship between the meshing posture of the sun gear 30s and the tooth root stress applied to the tooth root. As shown in FIG. 4, (a) a good tooth contact state (corresponding to FIG. 3 (a)) and (b) a bad tooth contact state (corresponding to FIG. 3 (b)) corresponding to the present embodiment. Then, the tooth root stress applied to the tooth base of the sun gear 30s is lower when the tooth contact is good. On the other hand, when the meshing posture is poor, the tooth root stress applied to the tooth root is about 75% higher than when the posture is good, so that the tooth root strength is disadvantageous and the gear strength is also reduced. In this embodiment, since the meshing posture is good, the root stress is not increased, and the reduction in gear strength is also suppressed.

  FIG. 5 shows the relationship between the meshing posture of the sun gear 30s and the meshing transmission error. As shown in FIG. 5, in the (a) good tooth contact state and (b) bad tooth contact state corresponding to the present embodiment, the good tooth contact state is compared to the bad tooth contact state. This reduces the meshing transmission error. On the other hand, if the meshing posture is bad, the meshing transmission error is increased by 35% compared to the case where the posture is good, so that vibration and noise generated during power transmission are worsened. In this embodiment, since the meshing posture is good, the meshing transmission error does not increase and the deterioration of vibration and noise is suppressed.

  From the above, in the present embodiment, even if the meshing reaction force is transmitted to the small-diameter gear 36 and the small-diameter gear is tilted, the sun gear 30 s is not tilted. Increase in tooth root stress and deterioration in meshing transmission error due to deterioration are suppressed, and as a result, deterioration in gear strength and deterioration in vibration and noise are suppressed. In this connection, it is possible to prevent an increase in size and weight due to an increase in strength of the planetary gear device 30.

  As described above, according to this embodiment, the spline fitting portion 78 between the sun gear 30 s and the start gear 36 is displaced by the inclination of the start gear 36 due to the meshing reaction force transmitted to the start gear 36. Since the engagement is transmitted to the small-diameter gear 36 and the reaction force is transmitted to the small-diameter gear 36, the sun gear 30s does not tilt and the meshing state of the planetary gear device 30 deteriorates. It is possible to suppress the deterioration of vibration and noise.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this invention is applied also in another aspect.

  For example, in the above-described embodiment, the automatic transmission 23 includes the continuously variable transmission 20 and the gear mechanism 22 in parallel between the turbine shaft 26 and the output shaft 25. It is not necessarily limited to this. The present invention includes a planetary gear device including a carrier to which power from a power source is input, a sun gear to which power input to the carrier is output, and a ring gear, and the power output from the sun gear is input. Any starter gear can be applied as long as the starter gear is provided.

  Further, in the above-described embodiment, the engine 14 that is an internal combustion engine is applied as a power source. However, the engine 14 may be appropriately changed as long as it functions as a power source such as an electric motor.

  The above description is only an embodiment, and the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.

14: Engine (power source)
23: Automatic transmission (automatic transmission for vehicles)
30: Planetary gear device 30s: Sun gear 30c: Carrier 30r: Ring gear 36: Small diameter gear (starting gear)
40: Large diameter gear (gear meshing with starting gear)
78: Spline fitting part

Claims (1)

A planetary gear device including a carrier to which power from a power source is input, a sun gear to which power input to the carrier is output, and a ring gear, and a starting gear to which power output from the sun gear is input In an automatic transmission for a vehicle equipped with
The sun gear and the starting gear are connected by spline fitting,
The spline fitting portion between the sun gear and the starting gear has a backlash larger than the displacement of the starting gear due to the inclination of the starting gear due to the meshing reaction force transmitted from the gear meshing with the starting gear to the starting gear. An automatic transmission for a vehicle characterized by the above.

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