JP6262400B2 - Automatic transmission - Google Patents

Description

  The present invention relates to an automatic transmission capable of shifting without interrupting torque transmission.

  In Patent Document 1, in a parallel two-shaft type continuously meshing transmission, in order to smoothly engage the dog clutch, a motor capable of rotating each shaft is provided, and the dog clutch is synchronized by synchronizing the dog clutch by driving the motor. A device that achieves smooth meshing without incurring a bad defect is disclosed.

  On the other hand, Japanese Patent Application Laid-Open No. 2012-127471 discloses an automatic transmission capable of shifting without interruption of torque transmission (hereinafter referred to as a seamless shift) in a parallel two-shaft type constant mesh transmission. For example, when performing an upshift to the second speed during traveling at the first speed, if a second-speed clutch ring that meshes with the second-speed gear is engaged, a coasting torque acts on the first-speed gear. The coasting torque is used to generate an axial force in the meshing release direction in the first-speed clutch ring to achieve a seamless shift to the second speed.

  By applying the technology shown in Patent Document 1 to an automatic transmission capable of achieving such a seamless shift and synchronizing the dog clutch driven by the motor, a smooth shift can be performed even when the vehicle is stopped. Be expected. However, since the shift time is very short in the running state, the change in the rotation speed of the input shaft of the transmission during the shifting in the running state is large. If a motor or the like is separately provided, the rotation speed of the motor is the same. Therefore, torque due to the inertia of the motor is generated, and this inertia torque is transmitted to the input shaft of the transmission to cause a shock at the time of upshifting.

JP 2009-156339 A

  An object of the present invention is to provide an automatic transmission capable of seamless shifting while avoiding a shock caused by an inertia torque of a motor at the time of upshifting.

To achieve the above object, in the automatic transmission according to the present invention, the first low-speed gear and the first high-speed gear fixed to the first shaft on the input side or supported so as to be relatively rotatable, and fixed to the second shaft on the output side. Alternatively, the second low-speed gear supported relative to the first low-speed gear and always engaged with the first low-speed gear and the second high-speed gear always engaged with the first high-speed gear and the first low-speed gear or the second 2. It has a low speed clutch ring dog that meshes with the dog of the low-speed relative rotating body that is one of the low-speed gears, and when the torque acts on the low-speed clutch ring dog from the dog of the low-speed relative rotating body, the axial engagement is released. A low-speed clutch ring having a low-speed side guide portion that moves to the side, and a high-speed side relative rotating body that is either the first high-speed gear or the second high-speed gear by moving toward the axial meshing side A high-speed clutch ring having a high-speed clutch ring dog that meshes with a dog, and that has a high-speed side guide portion that moves to an axial engagement release side when torque is applied to the high-speed clutch ring dog from the dog of the high-speed side relative rotating body. A shift actuator capable of moving the low-speed clutch ring and the high-speed clutch ring in the axial meshing direction by movement toward the axial meshing side and allowing movement to the axial meshing release side; A motor capable of driving a shaft, and a one-way clutch that can be connected / disconnected between the first shaft and the motor and that is released when the motor rotates in the forward direction and is engaged when the motor rotates in the reverse direction .

  Therefore, when the vehicle is stopped, the first shaft on the input side is rotationally driven by the motor to synchronize the meshing positions of the dogs, enabling shifting, and if necessary, the motor and the first shaft on the input side It becomes possible to cut off the power transmission relationship, and by eliminating the inertia of the motor as appropriate, it is possible to achieve a seamless shift that avoids a shock caused by the inertia of the motor at the time of upshifting.

1 is a schematic system diagram illustrating an automatic transmission according to a first embodiment. FIG. 2 is a schematic diagram illustrating the operation of the first dog clutch mechanism in the upshift from the first speed to the second speed in the automatic transmission of the first embodiment. 4 is a time chart showing an upshift from the first speed to the second speed in the automatic transmission according to the first embodiment. 3 is a flowchart illustrating motor drive control processing during downshift according to the first embodiment. 4 is a time chart showing a downshift from the fourth speed to the first speed accompanying sudden deceleration in the automatic transmission according to the first embodiment.

[Example 1]
FIG. 1 is a schematic system diagram showing an automatic transmission according to a first embodiment. An automatic transmission 3 is connected to the engine output shaft 1 a of the engine 1 through a clutch 2. The automatic transmission 3 includes an input-side first shaft 301 connected to the automatic transmission side of the clutch 2, and an output-side second shaft 302 arranged in parallel with the first shaft 301. On the first shaft 301, a first-speed drive gear 311 (corresponding to a first low-speed gear) that rotates integrally with the first shaft 301, a third-speed drive gear 331, and a first shaft 301 can rotate relative to the first shaft 301. A supported second speed drive gear 321 (corresponding to a first high speed gear) and a fourth speed drive gear 341 are provided. On the second shaft 302, the first speed driven gear 312 (corresponding to the second low speed gear) supported so as to be rotatable relative to the second shaft 302, the third speed driven gear 332, and the second shaft 302 rotate integrally. A second-speed driven gear 322 (corresponding to a second high-speed gear) and a fourth-speed driven gear 342 are included. Each driven gear always meshes with each drive gear.

  Further, the motor 7 is connected to the first shaft 301 via a gear 72 and a gear 331. A one-way clutch 71 is provided between the gear 72 and the motor 7. The one-way clutch 71 is engaged when the first shaft 301 is driven to rotate forward, and transmits torque from the first shaft 301 to the motor 7 side. Further, it is released when the motor 7 is driven to rotate forward, and the torque transmission from the motor 7 to the first shaft 301 side is cut off. In other words, when the motor 7 is driven in reverse rotation, the one-way clutch 71 is engaged and the first shaft 301 is driven in reverse rotation. On the other hand, in a state where driving torque cannot be applied to the motor 7 even when the first shaft 301 is rotating forward (a state lower than the rotational speed of the motor 7), the first shaft 301 and the motor 7 are disconnected. Therefore, when the forward driving torque of the first shaft 301 is generated, torque is always transmitted to the motor 7, so that the motor 7 functions as an alternator (generator) and is driven to rotate in reverse when necessary. To function as. Details will be described later.

  The transmission controller 3 a determines a desired gear position based on various sensors and shift signals not shown, and outputs a shift actuator drive signal to the shift actuator 30. The shift actuator 30 is configured to be able to move the first shift fork 31 and the second shift fork 32 in the axial direction. The shift actuator 30 controls the position of a shift drum having a groove engaged with each shift fork on the outer periphery by a motor. The first shift fork 31 and the second shift fork 32 have positioning mechanisms 31b and 32b that can be biased to predetermined positions in the axial direction. The positioning mechanisms 31b and 32b allow a slight movement in the axial direction in accordance with a change in the meshing position of the dog in accordance with the torque acting direction described later after each shift fork is positioned by the shift actuator 30. A holding force at a predetermined axial position is applied to each shift fork at a plurality of positions. Details will be described later.

  The first speed driven gear 312 and the third speed driven gear 332 are disposed adjacent to each other. The second speed drive gear 321 and the fourth speed drive gear 341 are disposed adjacent to each other. A side surface of the first driven gear 312 facing the third driven gear 332 has a first dog 312 a extending in the axial direction. Similarly, a third dog 332 a is provided on the side surface of the third driven gear 332 facing the first driven gear 312. A side surface of the second drive gear 321 facing the fourth drive gear 341 has a second dog 321a extending in the axial direction. Similarly, a fourth dog 341 a is provided on the side surface of the fourth drive gear 341 facing the second drive gear 321.

  Between the first speed driven gear 312 and the third speed driven gear 332, and between the second speed drive gear 321 and the fourth speed drive gear 341, there are first and second dog clutch mechanisms DG1 and DG2. The first dog clutch mechanism DG1 is installed on the outer periphery of the first clutch ring cam 400 fixedly installed on the second shaft 302 and meshes with the first shift fork 31 so as to be relatively rotatable. A first clutch ring 33 is provided. On the outer periphery of the first clutch ring cam 400, there is a V-shaped groove 401 formed on the outer peripheral surface. The V-shaped groove 401 includes a first speed side inclined groove 401 a that is inclined toward the positive rotation direction side of the first shaft 301 and a third speed side inclined groove 401 c.

  The end of the first clutch ring 33 facing the first speed driven gear 312 side has a holding groove 401b connected to the first speed side inclined groove 401a and parallel to the axial direction. Similarly, an end portion of the first clutch ring 33 facing the third speed driven gear 332 side has a holding groove 401d connected to the third speed side inclined groove 401c and parallel to the axial direction. The second dog clutch mechanism DG2 also includes the second clutch ring 34, the second clutch ring cam 500, the V-shaped groove 501, the second speed side inclined groove 501a, and the fourth speed side inclined groove 501c similar to the first dog clutch mechanism DG1. And holding grooves 501b and 501d. Since the configuration is the same as that of the first dog clutch mechanism DG1, description thereof is omitted.

  The first clutch ring 33 includes a cylindrical member 33e that can move relative to the outer periphery of the first clutch ring cam 400, and a first sleeve 33a that is expanded in diameter from the axial center to the outer diameter side of the cylindrical member 33e. Have. The first sleeve 33 a is a disk-shaped member that can be applied to the shift fork 31 while being held rotatably relative to the shift fork 31. The first clutch ring 33 includes a first-speed first clutch ring dog 33c extending from the first sleeve 33a in the axial direction of the side facing the first-speed driven gear 312 and an axial direction of the side facing the third-speed driven gear 332 A first-speed clutch ring dog 33d for the third speed extended to the inner side, a first projection 33b for guide that projects into the inner circumferential side of the cylindrical member 33e and is guided into the V-shaped groove 401 of the first clutch ring cam 400; Have.

  Similarly, the second clutch ring 34 includes a cylindrical member 34e that can move relative to the outer periphery of the second clutch ring cam 500, and a second diameter that is expanded from the axial center to the outer diameter side of the cylindrical member 34e. It has a sleeve 34a. The second sleeve 34 a is a disk-like member that can be applied to the shift fork 32 and an axial force while being held by the shift fork 32 so as to be relatively rotatable. The second clutch ring 34 includes a second-speed second clutch ring dog 34c extending from the second sleeve 34a in the axial direction of the side surface facing the second-speed drive gear 321, and a side shaft facing the fourth-speed gear 341. Second clutch ring dog 34d for the fourth speed extending in the direction, and the second guide protrusion 34b that protrudes to the inner peripheral side of the cylindrical member 34e and is guided into the V-shaped groove 501 of the second clutch ring cam 500. And having.

  Next, the upshift operation will be briefly described. As a specific example, a case where the upshift to the second speed is performed in the first speed traveling state will be described. FIG. 2 is a schematic diagram illustrating the operation of the first dog clutch mechanism in the upshift from the first speed to the second speed in the automatic transmission of the first embodiment. In the first speed, the first shift fork 31 is moved to the left side in FIG. As shown in FIG. 2A, in the first clutch ring 33, the guide first protrusion 33b is positioned in the holding groove 401b and the coasting torque is applied before the torque is applied to the first speed driven gear 312. However, it does not move in the axial direction.

  As shown in FIG. 2B, the tooth surface of the first clutch ring dog 33c for the first speed of the first clutch ring 33 is engaged with the first dog 312a of the first speed driven gear 312 when the driving torque is applied. Is formed with an inclined surface 33c1. When driving torque is applied from the first speed drive gear 311 to the first speed driven gear 312, the first clutch ring 33 is lifted toward the meshing release side along the inclined surface 33 c 1. As a result, the first guide protrusion 33b moves from the holding groove 401b to the position of the first-speed inclined groove 401a. However, the meshing between the first dog 312a of the first-speed driven gear 312 and the first-speed clutch ring dog 33c is continued, and the torque is transmitted. In performing this operation, the positioning mechanism 31b described above operates. That is, the axial position of the first clutch ring 33 after the lift is stably held while allowing the first shift fork 31 to move slightly in the axial direction along with the lift.

  Next, when the second shift fork 32 moves to the left in FIG. 1 and the second-speed second clutch ring dog 34c and the second dog 321a start to be engaged, the interlock state is established and the first-speed clutch ring is engaged. A coasting torque acts between the dog 33c and the first dog 312a. Then, as shown in FIG. 2C, since the first guide projection 33b moves along the first-speed inclined groove 401a, the first clutch ring 33 moves to the disengagement side, and the first-speed driven gear 312 is moved. The meshing between the first dog 312a and the first-speed clutch ring dog 33c is completely released. Since the force generated in the axial direction by the coasting torque associated with the interlock state is sufficiently larger than the holding force of the positioning mechanism 31b, the first shift fork 31 is moved quickly.

  That is, at the first speed, the second speed drive gear 321 and the second speed second clutch ring dog 34c are engaged, and the first speed driven gear 312 is utilized by utilizing the coasting torque accompanying the interlock state generated by this engagement. The engagement with the first clutch ring 33 is released. Therefore, the torque transmission state can always be maintained during the upshift. Such a shift operation is called seamless shift. The downshift is performed by the same action, and for details of the shift operation, refer to, for example, Japanese Patent Application Laid-Open No. 2012-127471.

(Operation of one-way clutch during upshift)
Next, the one-way clutch 71 during shifting will be described. FIG. 3 is a time chart showing an upshift from the first speed to the second speed in the automatic transmission according to the first embodiment. In the automatic transmission according to the first embodiment, when the seamless shift is performed as described above, the gear is immediately shifted if the engagement between the drive gear and the clutch ring is established at the post-shift gear stage. Assuming that the first shaft 301 was rotating at, for example, 1000 rpm at the first speed, and assuming that the second dog 321a of the second-speed drive gear 321 is rotating at, for example, 500 rpm from the relationship between the gear ratios of the first and second speeds. To do.

  At time t1, when the clutch 2 is slip-controlled and the shift actuator 30 is operated to move the second shift fork 32 in the axial direction and mesh with the second dog 321a, the rotation speed of the second clutch ring dog 34c for the second speed Is decelerated to 500 rpm at a stroke. Since the rotation speed of the first-speed drive gear 311 is reduced to 500 rpm, a coasting torque is generated between the first-speed first clutch ring dog 33c and the first-speed first clutch ring is generated by this coasting torque. The dog 33c moves in the mesh release direction, and the seamless shift is completed.

  Here, if the motor 7 is always rotating integrally with the first shaft 301, when the first shaft 301 is decelerated all at once, it is necessary to decelerate the rotation speed of the motor 7 as well. At this time, the influence of the motor inertia is extremely large, and there is a problem that a shock due to the inertia torque of the motor 7 occurs at the time of shift up. However, since the one-way clutch 71 is provided, when the coasting torque is applied to the first shaft 301, the one-way clutch 71 is automatically released, and the inertia of the motor 7 does not affect the shift. . That is, since the occurrence of the inertia torque of the motor 7 can be prevented, the amount of change in the output torque generated by the inertia torque immediately after time t1 can be suppressed small. At time t2, when the motor rotation speed decreases and coincides with the rotation speed of the first shaft 301, the one-way clutch 71 is engaged, and the motor 7 functions as an alternator.

(Operation of one-way clutch during downshift after vehicle stop)
Next, a downshift when the vehicle stops due to sudden deceleration will be described. FIG. 4 is a flowchart illustrating motor drive control processing during downshift according to the first embodiment. The automatic transmission according to the first embodiment needs to be synchronized during rotation in order to engage the dog. Therefore, in the first embodiment, when the downshift is performed by the transmission controller 3a, the downshift is performed by reversely rotating the motor 7 after the vehicle is stopped.

In step S1, it is determined whether or not the downshift is completed. When the downshift is completed, the process proceeds to step S4. When the downshift is not completed, the process proceeds to step S2.
In step S2, it is determined whether or not the motor rotational speed is 0, that is, whether or not the motor rotational speed has sufficiently decreased after the vehicle stops. If the motor rotational speed is 0, the process proceeds to step S3. Ends this control flow.
In step S3, the motor 7 is driven in reverse rotation. Thereby, since the one-way clutch 71 can be fastened and the 1st shaft 301 can be rotated, a downshift can be continued even after a vehicle stops.
In step S4, it is determined whether or not the motor 7 is being driven in reverse rotation. If the motor 7 is in reverse rotation, the process proceeds to step S5 to stop the motor drive. Otherwise, this control flow is ended.

FIG. 5 is a time chart showing a downshift from the fourth speed to the first speed accompanying sudden deceleration in the automatic transmission according to the first embodiment.
At time t11, when the driver depresses the brake pedal from the running state at the fourth speed and starts to decelerate, the coasting torque acts inside the automatic transmission, so that it functions as a generator by the driving torque of the engine 1. The one-way clutch 71 between the motor 7 and the first shaft 301 is in a released state. Therefore, the rotation speed of the motor 7 gradually decreases according to the inertia.

At time t12, when downshifting from the fourth speed to the third speed is performed, the clutch 2 is released. Note that the clutch 2 continues to be released when performing a continuous shift or when the vehicle is decelerated to stop the vehicle.
When the vehicle stops at time t13, the rotation of the first shaft 301 also stops, so that a downshift using the rotation of the first shaft 301 cannot be performed. At this time, the motor 7 has a slight rotational speed due to the influence of inertia.

When the rotation of the motor 7 stops at time t14, the motor 7 is driven in the reverse rotation as it is. By this reverse rotation drive, the one-way clutch 71 is engaged, and the first shaft 301 rotates reversely. Dog rotation is synchronized using the rotation of the first shaft 301, and the downshift is sequentially performed from the third speed to the second speed and the first speed toward the first speed, which is the target gear position when the vehicle is stopped.
When the downshift to the first speed is completed at time t15, the reverse rotation direction torque of the motor 7 is decreased. At this time, the one-way clutch 71 is automatically released.

As described above, the effects listed below are obtained in the first embodiment.
(1) a first-speed drive gear 311 (first low-speed gear) and a second-speed drive gear 321 (first high-speed gear) that are fixed (or relatively rotatable) to the input-side first shaft 301;
A first-speed driven gear 312 (second low-speed gear) that is supported (fixed or) relative to the output-side second shaft 302 so as to be relatively rotatable and always meshed with the first-speed drive gear 311 and a second-speed driven gear 322 that always meshed with the second-speed drive gear 321 ( Second high speed gear),
A first speed first clutch ring dog 33c that meshes with the first dog 312a (the dog of the low-speed relative rotating body that is either the first low-speed gear or the second low-speed gear) by the movement toward the axial meshing side. A V-shaped groove 401 of the first clutch ring cam 400 that moves to the axial engagement release side when torque is applied from the first dog 312a to the first speed first clutch ring dog 33c. A first clutch ring 33 (low speed clutch ring) having a first guide projection 33b (low speed side guide portion);
The second clutch ring dog 34c for the second speed that meshes with the second dog 321a (the dog of the high-speed relative rotating body that is either the first high-speed gear or the second high-speed gear) by the movement toward the axial meshing side. A V-shaped groove 501 of the second clutch ring cam 500 that moves to the axial meshing release side when torque is applied from the second dog 321a to the second clutch ring dog 34c for the second speed. A second clutch ring 34 (high speed clutch ring) having a guide second protrusion 34b (high speed side guide portion);
A first shift fork 31 capable of moving the first clutch ring 33 and the second clutch ring 34 in the axial meshing direction by movement toward the axial meshing side and allowing movement toward the axial meshing release side; A second shift fork 32 and a shift actuator 30;
A motor 7 capable of rotationally driving the first shaft 301;
A one-way clutch 71 (fastening means) capable of connecting / disconnecting between the first shaft 301 and the motor 7;
Equipped with.
Therefore, it is possible to obtain a power transmission relationship between the motor 7 and the first shaft 301 as necessary while enabling the shift when the vehicle is stopped, and by appropriately eliminating the inertia of the motor 7, A seamless shift that avoids the occurrence of inertia torque of the motor 7 can be achieved.

(2) The one-way clutch 71 is released when the motor 7 rotates forward and is engaged when the motor 7 rotates backward.
At the time of seamless shift, it is necessary to decelerate the rotation speed of the motor 7 at a stretch. The influence of the motor inertia is extremely large, and there is a problem that an excessive load is generated inside the transmission. However, since the one-way clutch 71 is provided, when the coasting torque is applied to the first shaft 301, the one-way clutch 71 is automatically released, and the inertia of the motor 7 does not affect the shift. .

(3) The transmission controller 3a (transmission control means) drives the motor 7 after the rotation of the first shaft 301 is stopped, and shifts while driving the first shaft 301 in the reverse rotation.
Therefore, the downshift can be continued even after the vehicle is stopped.

(Other examples)
As described above, the description is based on the first embodiment. However, the present invention is not limited to the above-described embodiment, and the present invention may be applied to an automatic transmission having another configuration. For example, in the first embodiment, a driven gear that is a relative rotating body is arranged on the second shaft 302 and a dog clutch mechanism that can selectively fix the driven gear to the second shaft 302 is shown. The first shaft 301 may be provided on both the first shaft 301 and the second shaft 302 in combination with each other.
Further, the present invention can be applied not only to the fourth forward speed but also to the second forward speed and further automatic transmissions with multiple stages.
In the first embodiment, an example in which the motor 7 and the first shaft 301 are connected via the one-way clutch 71 has been described. On the other hand, not only the one-way clutch 71 but also a two-way clutch capable of switching the locking direction may be employed, or a clutch capable of switching engagement / release may be applied to perform engagement control depending on the situation. Good.

Claims (2)

A first low speed gear and a first high speed gear supported by the first shaft on the input side so as to be fixed or relatively rotatable;
A second low-speed gear that is fixedly or relatively rotatably supported by the second shaft on the output side, and that always meshes with the first low-speed gear; and a second high-speed gear that always meshes with the first high-speed gear;
A low-speed clutch ring dog that meshes with a dog of the low-speed relative rotating body that is either the first low-speed gear or the second low-speed gear by movement toward the axial meshing side; A low-speed clutch ring having a low-speed side guide portion that moves to an axial meshing release side when torque is applied from the dog to the low-speed clutch ring dog;
A high-speed clutch ring dog that meshes with a dog of the high-speed side relative rotating body that is either the first high-speed gear or the second high-speed gear by moving toward the axial meshing side; A high-speed clutch ring having a high-speed side guide portion that moves to an axial engagement release side when torque acts on the high-speed clutch ring dog from a dog;
A shift actuator capable of moving the low-speed clutch ring and the high-speed clutch ring in the axial meshing direction by movement toward the axial meshing side and allowing movement to the axial meshing release side;
A motor capable of driving the first shaft;
A one-way clutch that can be connected and disconnected between the first shaft and the motor, and that is released when the motor rotates forward and is engaged when the motor rotates in reverse .
Automatic transmission equipped with. The automatic transmission according to claim 1, wherein
An automatic transmission provided with a shift control means for driving the motor after the rotation of the first shaft is stopped and shifting the first shaft while driving the reverse rotation of the first shaft .

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