JP2018066423A - Automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic transmission capable of enabling seamless shift suppressed in gear change shock while keeping fastening of a clutch between an engine and the automatic transmission.SOLUTION: An automatic transmission includes the automatic transmission capable of changing gear without interrupting torque transmission, a clutch for connecting and disconnecting an engine and the automatic transmission, and a controller for controlling the automatic transmission. When fastening failure of the clutch is detected, the controller executes upshift at an engine speed lower than an engine speed in upshift under a normal state of the clutch.SELECTED DRAWING: Figure 4

Description

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

  Patent Document 1 discloses an automatic transmission capable of shifting without interrupting torque transmission (hereinafter referred to as a seamless shift). 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.

JP2012-127471A

However, if an engagement failure occurs in which the clutch between the engine and the transmission cannot be released, the engine inertia torque is output if the input side rotational speed is reduced by upshifting while the clutch is engaged. There was a problem that shift shock was likely to increase. On the other hand, when a clutch engagement failure occurs, if a gear ratio is fixed, the occurrence of a gear shift shock can be avoided. Is too effective. Further, if the gear ratio is fixed at a high gear, the driving torque becomes insufficient and traveling itself becomes difficult.
An object of the present invention is to provide an automatic transmission that can perform a seamless shift while suppressing a shift shock even when a clutch between an engine and an automatic transmission is still engaged.

  In order to achieve the above object, in the automatic transmission according to the present invention, an automatic transmission capable of shifting without interruption of torque transmission, a clutch capable of connecting / disconnecting between the engine and the automatic transmission, and the automatic transmission A controller for controlling the clutch, and when detecting a clutch engagement failure, the controller performs an upshift at an engine speed lower than the engine speed during an upshift when the clutch is normal. did.

  Therefore, it is possible to suppress excessive engine braking force while suppressing shift shock during upshifting. In addition, the vehicle can be accelerated to a relatively high vehicle speed by upshifting.

1 is a schematic system diagram illustrating an automatic transmission according to a first embodiment. FIG. 6 is a schematic diagram illustrating an operation of a first dog clutch mechanism in an upshift from the first speed to the second speed in the automatic transmission according to the first embodiment. FIG. 6 is a schematic diagram illustrating an operation of a first dog clutch mechanism in an upshift from the first speed to the second speed in the automatic transmission according to the first embodiment. 3 is a shift map of the automatic transmission according to the first embodiment. 3 is a flowchart illustrating a shift map selection process of the automatic transmission according to the first embodiment. 3 is a time chart showing a shift state of a comparative example and Example 1. 6 is a flowchart illustrating a shift control process according to a second 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 has a first shaft 301 connected to the automatic transmission side of the clutch 2 and a second shaft 302 disposed in parallel with the first shaft 301. On the first shaft 301, a first speed drive gear 311, a second speed drive gear 321, a third speed drive gear 331, and a fourth speed drive gear 341 supported so as to be rotatable relative to the first shaft 301, Have On the second shaft 302, a first speed driven gear 312 fixed to the second shaft 302 and rotating integrally with the second shaft 302, a second speed driven gear 322, a third speed driven gear 332, and a fourth speed driven gear 342 are provided. Have. Each driven gear always meshes with each drive gear.

  The transmission controller 3 a determines a desired shift stage from a shift map, which will be described later, based on various sensors and shift signals not shown in the figure, 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 30a having a shift groove 30b engaged with the shift forks 31 and 32 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 dog meshing position accompanying the torque acting direction described later after the shift forks 31 and 32 are positioned by the shift actuator 30. At the same time, holding forces at predetermined axial positions are applied to the shift forks 31 and 32 at a plurality of positions. Details will be described later.

  The first speed drive gear 311 and the third speed drive gear 331 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 drive gear 311 facing the third drive gear 331 has a first dog 311 a extending in the axial direction. Similarly, a third dog 331a is provided on the side surface of the third drive gear 331 facing the first drive gear 311. 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 drive gear 311 and the third speed drive gear 331 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 first shaft 301 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 gently inclined groove 401a1 that is inclined toward the positive rotation direction side of the first shaft 301, and a first-speed-side suddenly inclined groove 401a2 that is steeper than the first-speed side gently inclined groove 401a1. The first-speed side inclined groove 401a is formed. Similarly, the 3rd speed which consists of the 3rd speed side gentle inclination groove | channel 401c1 which inclines toward the negative rotation direction side of the 1st shaft 301, and the 3rd speed side steep inclination groove | channel 401c2 steeper than the 3rd speed side gentle inclination groove | channel 401c1. Side inclined groove 401c. The tip of the V-shaped groove between the 1st-speed side inclined groove 401a and the 3rd-speed side inclined groove 401c is a neutral position in a meshed state, and after the meshing is released, a first guide for guidance which will be described later by the positioning mechanism 31b. The protrusion 33b is held in a neutral position that is the tip of the V-shaped groove.

  In other words, the outer periphery of the first clutch ring cam 400 has a first-speed side inclined groove 401a and a third-speed side inclined groove 401c that are formed along the outer periphery and intersect the axial direction, and intersect with the axial direction. The first-speed side gentle inclination groove 401a1 and the third-speed side gentle inclination groove 401c1 having a small angle, and the first-speed side steep inclination groove 401a2 and the third-speed side steep inclination groove 401c2 having a large intersection angle with the axial direction are provided. In addition, each inclined groove is formed such that the angle of intersection with the axial direction is substantially constant with respect to the axial position. Details will be described later.

  The end of the first clutch ring 33 facing the first-speed drive gear 311 side has a holding groove 401b connected to the first-speed side inclined groove 401a and parallel to the axial direction. Similarly, the end portion of the first clutch ring 33 facing the third speed drive gear 331 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 surface facing the first-speed drive gear 311 and a side shaft facing the third-speed gear 331. First clutch ring dog 33d for the third speed extending in the direction, and first protrusion 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. And having.

  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. 2 and 3 are schematic views showing 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 before the torque is applied to the first-speed drive gear 311 and the coasting torque is reduced. Even if it acts, 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 311a of the first speed drive gear 311 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 311a of the first-speed drive gear 311 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 311a. Then, as shown in FIG. 3C, as a first process, the first guide projection 33b moves along the first-speed side gently inclined groove 401a1. 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. Since the first-speed side gentle inclined groove 401a1 has an axial movement amount relative to the rotational movement amount larger than that of the first-speed side steeply inclined groove 401a2, the first-speed clutch ring dog 33c moves relatively quickly to the axial direction release side. Let

  Then, the first guide projection 33b moves in the first-speed side gently inclined groove 401a1, and the axial tooth tip of the first dog 311a of the first-speed drive gear 11 and the axial tooth tip of the first-speed clutch ring dog 33c. When the axial position exceeds a predetermined position PX, the guide first protrusion 33b moves along the first-speed steeply inclined groove 401a2 as a second process, as shown in FIG. 3D. The first-speed steeply inclined groove 401a2 has an axial movement amount relative to the rotational movement amount that is smaller than that of the first-speed gently inclined groove 401a1, and therefore moves the first-speed clutch ring dog 33c to the axial direction releasing side relatively slowly. . As a result, the first clutch ring 33 moves to the engagement release side, and the engagement between the first dog 311a of the first-speed drive gear 11 and the first-speed clutch ring dog 33c is completely released.

  That is, the first-speed drive gear 311 is engaged by engaging the second-speed drive gear 321 and the second-speed second clutch ring dog 34c at the first speed, and using the coasting torque accompanying the interlock state generated by the engagement. And the first clutch ring 33 are disengaged. Therefore, the torque transmission state can always be maintained during the upshift. Such a shift operation is called seamless shift.

  FIG. 4 is a shift map of the automatic transmission according to the first embodiment. This shift map has the vehicle speed VSP on the horizontal axis and the accelerator pedal opening APO on the vertical axis. Hereinafter, a point defined by the vehicle speed VSP and the accelerator pedal opening APO on the shift map is referred to as an operating point. In the shift map, an upshift shift line indicated by a solid line or a dotted line in FIG. 4 is set, and an upshift is performed when the operating point crosses the shift line from the low shift stage side to the high shift stage side. During normal travel, gear shifting is performed based on the first map indicated by the solid line in FIG. The first map is set so that when the accelerator pedal opening APO is increased, the engine speed Ne is further increased to perform acceleration, and then upshift is performed. When an upshift is performed using the first map, the clutch 2 is slip-engaged, and transmission of inertia torque generated when the engine speed Ne is reduced is suppressed, and a shift shock is reduced.

  Here, a case where the clutch 2 is in a failure failure will be described. Since the automatic transmission 3 according to the first embodiment is a seamless shift, the shift itself can be achieved even when the clutch 2 is engaged. However, since the inertia torque of the engine 1 is all transmitted to the output side with a decrease in the engine speed at the time of upshifting, there is a problem that a shift shock becomes large. In particular, if a clutch engagement failure occurs during traveling at a low speed and a high vehicle speed, a large engine braking force may be generated, which may cause the driver to feel uncomfortable. In view of this, a second map is provided that performs an upshift at a predetermined engine speed regardless of the accelerator pedal opening APO when the clutch 2 fails to engage.

  The dotted line in FIG. 4 is the second map. In the second map, an upshift line set in parallel with the accelerator pedal opening axis is set with a predetermined vehicle speed VSP as a threshold value. Therefore, the engine speed Ne is set so as not to increase too much even if the accelerator pedal opening APO increases. Further, the upshift line from the 3rd speed to the 4th speed is not set, and the upshift up to the 3rd speed is allowed and the upshift to the 4th speed is prohibited. In other words, when a clutch 2 malfunction occurs, if a gear ratio is fixed, the occurrence of a gear shift shock can be avoided, but if the gear ratio is fixed at a low gear stage such as the first speed or the second speed, the vehicle speed is increased. The engine braking force is too effective. Further, if the gear ratio is fixed at a high gear stage such as the fourth speed, the driving torque becomes insufficient, and traveling itself becomes difficult. Thus, by allowing upshifts up to the third speed and prohibiting upshifts to the fourth speed, the vehicle speed VSP is ensured, and excessive engine braking force is suppressed while avoiding insufficient driving force.

FIG. 5 is a flowchart illustrating a shift map selection process of the automatic transmission according to the first embodiment.
In step S1, it is determined whether or not a clutch 2 engagement failure has occurred. If normal, the process proceeds to step S2 to select a normal first map. On the other hand, if a clutch engagement failure is detected, the process proceeds to step S3 to select the second map. The detection of the engagement failure of the clutch 2 detects the relative rotational speed between the engine rotational speed Ne and the first shaft 301 when, for example, a release command or a slip control command to the clutch 2 is output. Then, when the relative rotational speed is less than a predetermined value indicating the engagement failure, it may be determined that the clutch 2 is in the engagement failure.

FIG. 6 is a time chart showing the shift state of the comparative example and the first embodiment. Here, the comparative example is an example in which the first map is continuously used when a clutch engagement failure occurs.
In the case of the comparative example, when the accelerator pedal opening APO is increased, the engine speed Ne is further increased. Therefore, when the operating point crosses the upshift line at the high engine speed Ne at time t11 or t12, the inertia torque of the engine 1 is shifted to the output side when the engine speed Ne is reduced at a stretch along with the upshift. There is a problem that the shift shock increases as reflected and indicated by acceleration.
On the other hand, in the case of the first embodiment, the upshift is performed when the engine speed Ne is low regardless of the accelerator pedal opening APO. it can. In addition, since the upshift is possible up to the third speed, the vehicle can be accelerated to a relatively high vehicle speed without generating excessive engine braking force. In addition, since the upshift to the fourth speed is prohibited, there will be no excessive driving force shortage.

The effect based on the said Example 1 is demonstrated.
(1) an automatic transmission 3 capable of shifting without interruption of torque transmission, a clutch 2 capable of connecting / disconnecting between the engine 1 and the automatic transmission 3, a transmission controller 3a for controlling the automatic transmission 3, When the clutch controller 2a detects the engagement failure of the clutch 2, the transmission controller 3a performs upshift at an engine speed lower than the engine speed at the time of upshift when the clutch 2 is normal.
Therefore, it is possible to suppress excessive engine braking force while suppressing shift shock during upshifting. Moreover, it can accelerate to a relatively high vehicle speed by upshifting.

(2) When the transmission controller 3a detects the engagement failure of the clutch 2, the transmission controller 3a prohibits upshifting to the fourth speed (high gear stage).
Therefore, traveling can be continued while avoiding insufficient driving force.
(3) The transmission controller 3a includes a first map (first shift map) in which a predetermined shift line is set in a plane defined by the vehicle speed axis and the accelerator pedal opening axis, and when the clutch 2 is malfunctioning. A second map to be used (second shift map), and the shift line of the second map is set in parallel to the accelerator pedal opening axis.
Therefore, regardless of the accelerator pedal opening APO, an upshift can be performed when the predetermined engine speed is reached, and a shift shock can be suppressed.

(Example 2)
Next, Example 2 will be described. Since the basic configuration is the same as that of the first embodiment, only different points will be described. FIG. 7 is a flowchart illustrating a shift control process according to the second embodiment. In Example 1, the example provided with the 2nd map different from a normal 1st map was shown. On the other hand, in the second embodiment, the normal shift control uses the first map, and at the time of clutch engagement failure, upshift is performed based on a predetermined condition.

In step S11, it is determined whether or not an engagement failure has occurred in the clutch 2. If normal, the process proceeds to step S12, and the normal first map is selected to perform normal shift control. On the other hand, if a clutch engagement failure is detected, the process proceeds to step S13.
In step S13, it is determined whether or not the current speed is 3rd speed or higher. If it is determined that the current speed is 3rd speed or higher, the process proceeds to step S14 to fix the speed. On the other hand, if it is determined that the speed is less than the third speed, the process proceeds to step S15.
In step S15, it is determined whether or not the engine speed Ne is equal to or greater than a predetermined engine speed Ne1, and if it is equal to or greater than Ne1, the process proceeds to step S17 to perform an upshift. On the other hand, when it is less than Ne1, the process proceeds to step S16 to maintain the current gear position.

  That is, by allowing the upshift so that the engine speed Ne is equal to or less than the predetermined engine speed Ne1 that does not generate excessive engine braking force, the same effects as those of the first embodiment can be obtained.

(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, the present invention is not limited to the automatic transmission according to the first embodiment, and can be applied to a transmission capable of seamless shift disclosed in, for example, Japanese Patent No. 4646910.
Further, the present invention can be applied not only to the fourth forward speed but also to an automatic transmission having a further multi-stage. For example, in the case of 6 forward speeds, upshifts up to the 4th speed may be allowed and upshifts to the 5th and 6th speeds may be prohibited.

1 Engine 1a Engine output shaft 2 Clutch 3 Automatic transmission 3a Transmission controller 30 Shift actuator

Claims (3)

An automatic transmission capable of shifting without interruption of torque transmission;
A clutch capable of connecting and disconnecting between the engine and the automatic transmission;
A controller for controlling the automatic transmission;
With
When the clutch detects a clutch engagement failure, the controller performs an upshift at an engine speed lower than the engine speed at the time of upshift when the clutch is normal. The automatic transmission according to claim 1, wherein
The automatic transmission, wherein the controller prohibits an upshift to a high gear position when detecting an engagement failure of the clutch. The automatic transmission according to claim 1 or 2,
The controller includes a first shift map in which a predetermined shift line is set in a plane defined by a vehicle speed axis and an accelerator pedal opening axis, and a second shift map used when the clutch is broken. And an automatic transmission characterized in that the shift line of the second shift map is set in parallel with the accelerator pedal opening axis.

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