JP4595371B2 - Vehicle power transmission device - Google Patents

Description

  The present invention relates to a power transmission device for a vehicle that includes a main transmission path and an auxiliary transmission path that transmit engine driving force to driving wheels in parallel.

  Conventionally, there has been proposed a power transmission device for a vehicle including a main transmission path and an auxiliary transmission path that transmit engine driving force to driving wheels in parallel (see Patent Documents 1 and 2).

In Patent Document 1, a rotation of an input shaft driven by an engine is transmitted to a driven shaft via a belt-type continuously variable transmission, and a reduction gear train having a reduction ratio near the lowest (LOW). Forward and reverse auxiliary transmission paths that transmit to the driven shaft. A forward sub-transmission path having a reduction ratio in the vicinity of the lowest position is used when starting forward, and a one-way clutch (hereinafter also referred to as OWC) is operated during subsequent travel to move from the forward sub-transmission path to the main transmission path. The stepless speed change is performed, and the reverse auxiliary speed change path is used during reverse. Patent Document 2 has a configuration in which the reverse sub-transmission for Patent Document 1 is omitted and only the main transmission path is used during reverse travel.
JP-A-5-44811 JP-A-8-14354

    However, in the above conventional example, the power transmission on the main transmission path is always performed, the power transmission on the auxiliary transmission path is added at the time of forward start, and the power transmission from the auxiliary transmission path is transferred to the OWC when shifting to the normal traveling. It is cut off by. For this reason, when the vehicle starts moving forward, power is transmitted by both the main transmission path and the sub-transmission path, and when the reduction ratios of both paths are shifted, the belt of the belt type continuously variable transmission constituting the main transmission path There was a risk of causing power consumption such as an interlock due to slipping or power circulation.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a vehicle power transmission device that can suppress power consumption during forward start.

The present invention is a vehicle power transmission device including a main transmission path capable of shifting to transmit driving force of an engine to a driving wheel and a sub transmission path having a fixed reduction ratio in parallel downstream of a forward / reverse switching mechanism , The auxiliary transmission path has its fixed reduction ratio set near the maximum transmission ratio of the main transmission path and lower than the maximum transmission ratio, and the output portion is connected to the drive wheel via the final reduction gear. The input portion is coupled to introduce reverse drive force that is reversed during reverse operation of the forward / reverse switching mechanism, and is driven in the forward direction from the input portion of the main transmission path via the first one-way clutch. The main transmission path introduces a driving force in the forward direction from the engine to the input section when the forward / reverse switching mechanism moves forward , and an output section of the main transmission path is output to the auxiliary transmission path via the second one-way clutch. To move forward It was constructed by connecting to drive the.

Therefore, in the present invention, a shiftable main transmission path for transmitting the driving force of the engine to the drive wheels and a sub-transmission path having a fixed reduction ratio are provided in parallel downstream of the forward / reverse switching mechanism , The fixed reduction ratio is set near the maximum transmission ratio of the main transmission path and lower than the maximum transmission ratio, and the output unit is connected to the driving wheel via the final reduction gear, while the input unit is the first transmission unit. 1 is connected so as to be driven in the forward direction from the input part of the main transmission path via the one-way clutch, and the main transmission path introduces the driving force in the forward direction from the engine to the input part, and its output part is The output portion of the auxiliary transmission path is connected to be driven in the forward direction via two one-way clutches. For this reason, during forward start, both the main transmission path and the auxiliary transmission path operate, but the fixed reduction ratio of the auxiliary transmission path is lower than the maximum transmission ratio of the main transmission path, so that the output of the auxiliary transmission path is transmitted to the drive wheels. The output of the main transmission path is interrupted by the second one-way clutch, and even if the reduction ratios of the two paths are deviated, the main transmission path is constituted, for example, belt slip and power circulation of a belt type continuously variable transmission This makes it possible to start the vehicle forward without consuming power such as an interlock. Further, when the vehicle speed increases after starting and the gear ratio of the main transmission path is reduced and the drive speed of the output part increases, the output part of the auxiliary transmission path is connected to the auxiliary transmission path via the second one-way clutch. Can be automatically driven from the output part of the main transmission path, and the drive by this main transmission path causes the auxiliary transmission path to be disconnected from the input part of the main transmission path by the first one-way clutch. For example, the vehicle can be driven forward without power consumption such as belt slippage of a belt-type continuously variable transmission or interlock due to power circulation.
Moreover, the vehicle power transmission device includes a forward / reverse switching mechanism that introduces the driving force of the engine into the main transmission path during the forward operation and introduces the reverse driving force reversed during the reverse operation into the auxiliary transmission path. Sometimes the drive wheels can be driven directly via the final reduction gear only by the auxiliary speed change path. This is fixed when reverse travel is selected without waiting until the speed ratio of the main speed change path shifts to the lowest speed ratio regardless of the speed ratio of the main speed change path. It is possible to switch to a sub-transmission path that operates at a reduction ratio, and to perform a quick reverse operation. Since the main transmission path is cut off from the power transmission state by the second one-way clutch or the first one-way clutch according to the gear ratio, for example, belt slip and power of the belt type continuously variable transmission constituting the main transmission path. The vehicle can be driven backward without power consumption such as interlock due to circulation.

  Hereinafter, a power transmission device for a vehicle according to the present invention will be described based on an embodiment.

  1 to 4 show a first embodiment of a vehicle power transmission device to which the present invention is applied. FIG. 1 is a skeleton diagram of the vehicle power transmission device, and FIG. 2 is a diagram at the time of forward start and forward travel. FIG. 3 is a diagram for explaining the operation, FIG. 3 is a diagram for explaining the action during reverse travel, and FIG.

  In FIG. 1, a vehicle power transmission device includes a starting element 1 for introducing power from an engine E, a forward / reverse switching mechanism 2, and a continuously variable transmission that continuously outputs the output from the forward / reverse switching mechanism 2. A main transmission path 3 composed of a machine 21, a sub-transmission path 4 composed of a reduction gear train that decelerates and outputs the output from the forward / reverse switching mechanism 2 with a reduction ratio near the lowest (LOW), and a differential mechanism 8. And a final reduction device 5 that finally decelerates the outputs of the main transmission path 3 and the auxiliary transmission path 4, and the drive shaft 6 and the drive wheels 7 are driven by the left and right outputs of the final reduction apparatus 5.

  The starting element 1 includes a torque converter or a starting clutch that introduces power from the engine E, and drives the input shaft 10 of the forward / reverse switching mechanism 2. In the illustrated example, a torque converter including a pump impeller, a stator, a turbine runner, and the like is used.

  The forward / reverse switching mechanism 2 functions to switch the rotational direction input to the main transmission path 3 and the auxiliary transmission path 4 to either the forward direction or the reverse direction. The sun gear 12, the carrier 13, and the ring gear 14 , A forward clutch 15 and a reverse brake 16, and first and second input shafts 17 and 18. The second input shaft 18 is formed as a hollow shaft, and the first input shaft 17 is accommodated in the internal space. The input shaft 10 and the sun gear 12 of the planetary gear set 11 are connected to introduce power to the sun gear 12, and between the input shaft 10 and the first input shaft 17 that is the input shaft of the main transmission path 3. A forward clutch 15 made of a wet multi-plate clutch is disposed so as to be directly connectable, and the planetary gear set 11 is bypassed to allow forward power to be output. Further, the ring gear 14 and the second input shaft 18 to the auxiliary transmission path 4 are connected, and the carrier 13 can be fixed to the case 19 by a reverse brake 16 made of a wet multi-plate clutch. The reverse rotation thus made can be output as reverse power.

  The first input shaft 17 of the forward / reverse switching mechanism 2 outputs forward power that is not decelerated via the forward clutch 15, and the second input shaft outputs reverse power for reverse rotation that is decelerated by the planetary gear set 11. To do. While the forward power from the first input shaft 17 is being output, the second input shaft 18 is in a free rotation state in which the rotation is not restricted, and the rotation state is changed by the sub-transmission path 4 described later. While the reverse drive power is being output by the second input shaft 18, the first input shaft 17 connected to the input side of the main transmission path 3 is detached from the forward / reverse switching mechanism 2, and a main transmission path described later. 3 and the sub-transmission path 4 change the rotation state.

  The main transmission path 3 includes a belt-type continuously variable transmission 21 disposed between the first input shaft 17 and the output shaft 20, and a primary pulley 22 supported by the first input shaft 17 and an output shaft 20. A supported secondary pulley 23 and a primary pulley 22 and a metal belt 24 wound around the secondary pulley 23 are provided. The primary pulley 22 includes a fixed pulley 22A that is fixedly supported on the outer periphery of the first input shaft 17, and a movable pulley 22B that can move toward and away from the fixed pulley 22A. The secondary pulley 23 is integrated with the outer periphery of the output shaft 20. And a movable pulley 23B that can approach and leave the fixed pulley 23A.

  Although not shown, a hydraulic chamber is provided on the back surface of each movable pulley 22B, 23B, and each movable pulley 22B, 23B is moved toward and away from the fixed pulley 22A, 23A by changing the operating pressure of the hydraulic chamber. Thus, the gear ratio can be changed continuously by changing the width of each pulley groove. For example, it is configured to control the pulley groove width by changing the operating pressure of the primary pulley 22 and the secondary pulley 23 using the engine load due to the accelerator opening, the primary pulley rotation speed, and the secondary pulley rotation speed as input signals.

  The auxiliary transmission path 4 includes an input gear 30 connected to the second input shaft 18 of the forward / reverse switching mechanism 2, an intermediate gear 31 that meshes with the input gear 30, and an output of the main transmission path 3 that meshes with the intermediate gear 31. An output gear 32 rotatably supported on the shaft 20, and a reduction gear train that decelerates and outputs the output of the forward / reverse switching mechanism 2. The output gear 32 meshes with the input gear 5 </ b> A of the final reduction gear 5. In addition, the final reduction gear 5 is configured to be driven. The reduction ratio of the auxiliary transmission path 4 is set slightly higher than the lowest (LOW) reduction ratio of the main transmission path 3. The auxiliary transmission path 4 also includes first and second OWCs 33 and 34 between the input gear 30 and the first input shaft 17, and between the output gear 32 and the output shaft 20 of the main transmission path 3, respectively. Prepare.

  The first OWC 33 disposed between the input gear 30 and the first input shaft 17 is used when the input gear 30 rotates faster than the first input shaft 17 in the forward direction. In the case where the first input shaft 17 rotates fast forward with respect to the input gear 30, the input gear 30 functions to rotate integrally. Further, with respect to the reverse rotation, the first input shaft 17 is allowed when the first input shaft 17 rotates rapidly backward with respect to the input gear 30, and the input gear 30 reverses with respect to the first input shaft 17. When rotating fast toward the side, the first input shaft 17 functions to rotate integrally.

  The second OWC 34 disposed between the output gear 32 and the output shaft 20 of the main speed change path 3 is used when the output gear 32 rotates faster than the output shaft 20 in the forward direction. When the output shaft 20 rotates fast forward with respect to the output gear 32, the output gear 32 functions to rotate integrally. Further, with respect to the rotation on the reverse side, this is allowed when the output shaft 20 rotates fast in the reverse direction with respect to the output gear 32, and the output gear 32 rotates in the reverse direction with respect to the output shaft 20 quickly. In this case, the output shaft 20 functions to rotate integrally.

  The operation of the power transmission device for a vehicle having the above configuration will be described below.

[When the vehicle starts moving forward]
When the vehicle starts moving forward, the forward clutch 15 of the forward / reverse switching mechanism 2 is engaged. The reverse brake 16 maintains the released state. As a result, the rotation of the engine E is as follows: torque converter 1 → input shaft 10 → forward clutch 15 → first input shaft 17 → sub-transmission path 4 (first OWC 33 → input gear 30 → intermediate gear 31 → output gear 32) → final deceleration It is transmitted to the left and right drive wheels 7 through the path of the device 5 → drive shaft 6.

  That is, as shown in FIG. 2, the first input shaft 17 drives the belt-type continuously variable transmission 21 that constitutes the main transmission path 3, and drives the input gear 30 of the auxiliary transmission path 4 via the first OWC 33. . The belt-type continuously variable transmission 21 drives the output shaft 20 with the reduction ratio in the LOW state. In the auxiliary transmission path 4, the rotation of the input gear 30 is transmitted to the output gear 32 via the intermediate gear 31, and is set slightly higher than the reduction ratio in the maximum LOW state of the belt type continuously variable transmission 21. It is transmitted to the output gear 32 at a reduction ratio.

  The second OWC 34 compares the forward-side rotation of the output gear 32 and the output shaft 20, and causes the final reduction gear 5 to output the rotation on the output gear 32 side where the rotational speed is slightly higher (see region A in FIG. 4). . At this time, the reduction ratio between the input gear 30 and the output gear 32 is set to a magnitude suitable for starting the vehicle, and the intermediate gear 31 is interposed between the input gear 30 and the output gear 32. The gear 30 and the output gear 32 can rotate in the same direction to drive the vehicle forward.

  In this state, the rotation of the output shaft 20 of the main transmission path 3 having a slightly lower rotation speed is not transmitted to the output gear 32 but is allowed to rotate as it is, so that the main transmission path 3 and the auxiliary transmission path 4 In the meantime, it is possible to prevent power consumption such as belt slip of the belt-type continuously variable transmission 21 constituting the main transmission path 3 and interlock due to power circulation.

[When the vehicle is traveling forward]
When the forward clutch 15 is engaged in this manner to advance the vehicle forward and the vehicle speed gradually increases, the gear ratio of the belt-type continuously variable transmission 21 constituting the main transmission path 3 is gradually decreased, and the output shaft 20 rotates. The number will increase. When the rotational speed of the output shaft 20 exceeds the rotational speed of the output gear 32, the second OWC 34 drives the output gear 32 by the rotation of the output shaft 20 and drives the final reduction gear 5. As a result, the rotation of the crankshaft of the engine E is as follows: torque converter 1 → first input shaft 17 → main transmission path 3 (primary pulley 22 → metal belt 24 → secondary pulley 23 → output shaft 20) → second OWC 34 → output gear 32 → The transmission is transmitted to the left and right drive wheels 7 through the path of the final reduction gear 5 → the drive shaft 6.

  Further, the rotation increase of the output gear 32 is transmitted from the intermediate gear 31 to the input gear 30, and the first OWC 33 arranged between the input gear 30 and the first input shaft 17 is connected to the input gear 17 with respect to the first input shaft 17. Therefore, the input gear 30 is freely raised without being restricted by the first input shaft 17. For this reason, it is possible to prevent power consumption such as belt slip of the belt-type continuously variable transmission 21 constituting the main transmission path 3 and interlock due to power circulation between the main transmission path 3 and the auxiliary transmission path 4. The

  As a result, it is possible to smoothly shift from forward start in the auxiliary transmission path 4 by the input gear 30, the intermediate gear 31 and the output gear 32 to forward travel by the belt-type continuously variable transmission 21 which is the main transmission path 3. During the forward traveling of the vehicle, the gear ratio of the belt type continuously variable transmission 21 is controlled between LOW and OD (see region B in FIG. 4).

  When the engine brake is to be actuated by an operation such as returning the accelerator pedal to decelerate the vehicle during the forward traveling, the direct coupling clutch 35 disposed in parallel with the second OWC 34 is engaged to Is input to the engine E via the main transmission path 3, and the engine brake can be operated.

[When the vehicle is moving backward]
When the vehicle moves backward, the forward clutch 15 of the forward / reverse switching mechanism 2 is released and the reverse brake 16 is engaged. As a result, as shown in FIG. 3, the rotation of the crankshaft of the engine E is as follows: torque converter 1 → input shaft 10 → sun gear 12 → planetary gear 13A → ring gear 14 → second input shaft 18 → sub-transmission path 4 (input gear 30 → intermediate gear 31 → output gear 32) → final speed reduction device 5 → drive shaft 6 is transmitted to the left and right drive wheels 7 through a path. At this time, when the rotational direction of the ring gear 14 is opposite to the rotational direction of the sun gear 12 of the forward / reverse switching mechanism 2, the vehicle can reverse. In this case, the driving force is directly transmitted without passing through the first and second OWCs 33 and 34, so that the engine brake can be operated, and the reverse speed of the vehicle is controlled by a balance between the engine driving force and road surface resistance caused by a slope. can do.

  By the way, the reverse rotation of the second input shaft 18 and the input gear 30 is transmitted to the first input shaft 17 via the first OWC 33 and passes through the belt type continuously variable transmission 21 constituting the main transmission path 3. Then, the output shaft 20 is rotated in the same direction as the output gear 32. When the speed ratio of the belt type continuously variable transmission 21 exceeds the speed reduction ratio set in the auxiliary speed change path 4, the rotational speed of the output shaft 20 tends to be lower than the rotational speed of the output gear 32. The output shaft 20 is rotated by the output gear 32 via the second OWC 34, and the belt-type continuously variable transmission 21 rotates the primary pulley 22 from the secondary pulley 23 via the metal belt 24 and inputs the first input shaft 17. The gear 30 is rotated at a higher speed. The first OWC 33 allows rotation of the first input shaft 17 that rotates at a high speed with respect to the input gear 30 (see region C in FIG. 4). For this reason, it is possible to prevent power consumption such as belt slip of the belt-type continuously variable transmission 21 constituting the main transmission path 3 and interlock due to power circulation between the main transmission path 3 and the auxiliary transmission path 4. The

  Further, when the speed ratio of the belt type continuously variable transmission 21 is equal to or less than the speed reduction ratio set in the auxiliary transmission path 4, the rotational speed of the output shaft 20 becomes higher than the rotational speed of the output gear 32. The 2OWC 34 allows the output shaft 20 to rotate at a high speed (see region D in FIG. 4). For this reason, it is possible to prevent power consumption such as belt slip of the belt-type continuously variable transmission 21 constituting the main transmission path 3 and interlock due to power circulation between the main transmission path 3 and the auxiliary transmission path 4. The

  In the present embodiment, the following effects can be achieved.

  (A) A shiftable main transmission path 3 for transmitting the driving force of the engine E to the drive wheels 7 and a sub-transmission path 4 having a fixed reduction ratio are provided in parallel, and the sub-transmission path 4 has the fixed reduction ratio described above. The speed ratio is set near the maximum speed ratio of the main speed change path 3 and lower than the maximum speed ratio, and the output section 32 is connected to the drive wheel 7 via the final reduction gear 5, while the input section 30 is the first speed ratio. 1 is connected so as to be driven in the forward direction from the input portion 17 of the main transmission path 3 via the one-way clutch 33, and the main transmission path 3 introduces the driving force in the forward direction from the engine E to the input section 17, The output unit 20 is connected via the second one-way clutch 34 so as to drive the output unit 32 of the auxiliary transmission path 4 in the forward direction.

  For this reason, both of the main transmission path 3 and the auxiliary transmission path 4 operate during forward start, but the fixed speed reduction ratio of the auxiliary transmission path 4 is lower than the maximum transmission ratio of the main transmission path 3. The output is transmitted to the drive wheel 7, the output of the main transmission path 3 is interrupted by the second one-way clutch 34, and the main transmission path 3 is formed even if the reduction ratios of both paths are deviated. The vehicle can be started forward without power consumption such as belt slippage of the transmission 21 or interlock due to power circulation.

  Further, when the vehicle speed increases after the start and the gear ratio of the main transmission path 3 is decreased and the drive speed of the output section 20 increases, the output section of the auxiliary transmission path 4 via the second one-way clutch 34. 32 can be automatically driven from the output unit 20 of the main transmission path 3 in place of the auxiliary transmission path 4, and the auxiliary transmission path 4 is driven by the first one-way clutch 33 by the driving by the main transmission path 3. Is cut off from the input unit 17 of the main transmission path 3 and the main transmission path 3 is configured. For example, the belt-type continuously variable transmission 21 moves forward without causing power consumption such as belt slippage or interlock due to power circulation. It can be run.

  (A) As a power transmission device for a vehicle, a forward / reverse switching mechanism 2 that introduces a driving force of the engine E into the main transmission path 3 during forward operation and introduces a reverse driving force that is reversed during reverse operation into the auxiliary transmission path 4. Therefore, the drive wheel 7 can be directly driven via the final reduction gear 5 only by the sub-transmission path 4 during reverse travel. This means that, when reverse travel is selected, it is fixed without waiting until the speed ratio of the main speed change path 3 shifts to the lowest speed ratio regardless of the speed ratio of the main speed change path 3. It is possible to switch to the sub-transmission path 4 that operates at the reduced reduction ratio, and to perform a quick reverse operation. Since the main transmission path 3 is cut off from the power transmission state by the second one-way clutch 34 or the first one-way clutch 33 according to the transmission ratio, for example, the belt-type continuously variable transmission 21 that constitutes the main transmission path 3. Thus, the vehicle can be driven backward without power consumption such as interlocking due to belt slippage or power circulation.

  (C) Since the main transmission path 3 is composed of the belt-type continuously variable transmission 21, the transmission ratio can be changed steplessly, and the vehicle is moved forward by the auxiliary transmission path 4 to change the transmission ratio. In accordance with this, it is possible to automatically switch to forward traveling by the main transmission path 3 comprising the continuously variable transmission 21.

  (D) Since the second one-way clutch 34 includes the direct-coupled clutch 35 arranged in parallel, the engine brake can be operated by fastening the direct-coupled clutch 35 when the engine brake is required as in deceleration.

  (E) The forward / reverse switching mechanism 2 includes a planetary gear set 11 including a sun gear 12, a carrier 13, and a ring gear 14, a forward clutch 15 that bypasses the planetary gear set 11 and connects the input / output units 10 and 17, and a planetary gear. Since the reverse brake 16 that obtains a reverse output by fixing any element of the gear set 11 is provided, the forward state or the reverse state can be easily switched by simply switching the forward clutch 15 and the reverse brake 16. Can be.

The skeleton figure of the power transmission device of the vehicle which shows one Embodiment of this invention. Similarly, the operation explanatory view at the time of forward start and forward travel. Similarly, the operation explanatory view at the time of reverse. The characteristic view which shows the operating characteristic in each area | region of the power transmission device of a vehicle.

Explanation of symbols

E Engine 1 Torque converter 2 as a starting element 2 Forward / reverse switching mechanism 3 Main transmission path 4 Sub transmission path 5 Final reduction gear 6 Drive shaft 7 Drive wheel 8 Differential mechanism 10 Input shaft 11 Planetary gear set 15 Forward clutch 16 Reverse brake 17 First input shaft 18 as the input section of the main transmission path 18 Second input shaft 20 Output shaft as the output section of the main transmission path 21 Belt type continuously variable transmission, continuously variable transmission 30 Input as the input section of the sub transmission path Gear 32 Output gear as output portion of auxiliary transmission path 33 First one-way clutch, first OWC
34 Second one-way clutch, second OWC
35 Direct clutch

Claims (4)

In a vehicle power transmission device including a main shift path capable of shifting the driving force of an engine to a drive wheel and a sub-transmission path having a fixed reduction ratio in parallel downstream of the forward / reverse switching mechanism ,
The auxiliary transmission path has a fixed reduction ratio set near a maximum transmission ratio of the main transmission path and lower than the maximum transmission ratio, and an output portion thereof is connected to a drive wheel via a final reduction gear. On the other hand, the input portion is coupled to introduce reverse drive force that is reversed during reverse operation of the forward / reverse switching mechanism, and is driven in the forward direction from the input portion of the main transmission path via the first one-way clutch. Connected so that
The main transmission path introduces a driving force in the forward direction from the engine to the input part when the forward / reverse switching mechanism is operated forward, and an output part of the main transmission path passes through the second one-way clutch to the forward part. A power transmission device for a vehicle, characterized in that it is connected so as to be driven. The forward / reverse switching mechanism includes a planetary gear set including a sun gear, a carrier, and a ring gear, a forward clutch that bypasses the planetary gear set and connects an input / output unit, and fixes any element of the planetary gear set. The vehicle power transmission device according to claim 1 , further comprising a reverse brake that obtains a reverse output .   The power transmission device for a vehicle according to claim 1, wherein the main transmission path is configured by a belt-type continuously variable transmission.   The power transmission device for a vehicle according to any one of claims 1 to 3, wherein the second one-way clutch includes a direct coupling clutch arranged in parallel.

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