JP2017048802A - Automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic transmission in which the state of rotation of a dog clutch can be detected without bringing about an increase in the cost of the automatic transmission.SOLUTION: The automatic transmission is provided that comprises a first gear fixed to or relatively rotatably supported by a first shaft, a second gear fixed to or relatively rotatably supported by a second shaft and always engaging with the first gear to establish a predetermined gear ratio, a clutch ring having a clutch ring dog for engaging with the first gear, an actuator for controlling a power transmission state in which the clutch ring dog is moved in the axial direction to engage with a dog and a power non-transmission state in which the clutch ring dog disengages from the dog, and a controller for calculating a relative rotation angle on the basis of a first cumulative rotation angle obtained by accumulating rotation angles detected by a first rotation angle sensor for detecting the rotation angle of the first shaft, a second cumulative rotation angle obtained by accumulating rotation angles detected by a second rotation angle sensor for detecting the rotation angle of the second shaft and multiplying the accumulated rotation angle by a prescribed gear ratio, and an initial value of relative rotation angle between a dog and a clutch ring dog.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an automatic transmission having a dog clutch.

  Patent Document 1 discloses a technique for individually providing a rotation angle sensor for detecting the position of each dog tooth and controlling synchronously based on detection results of these rotation angle sensors when controlling the engagement of the dog clutch. Yes.

Japanese Patent No. 4941256

However, in the always-meshing parallel twin-shaft automatic transmission, if rotation angle sensors are provided for all the rotating elements of the dog clutch as in the prior art, there is a problem that the cost increases.
An object of the present invention is to provide an automatic transmission that can detect the rotation state of a dog clutch without increasing the cost.

  In order to achieve the above object, in the automatic transmission according to the present invention, the first gear fixed to the first shaft or supported so as to be relatively rotatable, and the first gear supported so as to be fixed or relatively rotatable on the second shaft; A second gear having a predetermined gear ratio by always meshing, a clutch ring having a clutch ring dog that meshes with the dog of the first gear by movement toward the axial meshing side, and the clutch ring dog in the axial direction An actuator for controlling a power transmission state in which the dog is moved and meshed with the dog and a power non-transmission state in which the clutch ring dog and the dog are released; and a first rotation angle sensor for detecting a rotation angle of the first shaft. A second rotation angle sensor for detecting a rotation angle of the second shaft, a first cumulative rotation angle obtained by accumulating the rotation angles detected by the first rotation angle sensor, Based on a second cumulative rotational angle obtained by multiplying the rotational angle detected by the two rotational angle sensor by the predetermined gear ratio, and an initial value of a relative rotational angle between the dog and the clutch ring dog. And a controller for calculating the relative rotation angle.

  Therefore, it is possible to obtain the relative rotation angle between the dog of the relative rotating body and the clutch ring dog at a plurality of gear stages by using the first rotation angle sensor and the second rotation angle sensor, and the dog clutch without causing an increase in cost. The rotation state of can be detected.

1 is a schematic system diagram illustrating an automatic transmission according to a first embodiment. It is the schematic showing the fastening / release state of the dog clutch of Example 1. FIG. 6 is a time chart showing a cumulative rotation angle change when the dog clutch according to the first embodiment shifts from the engaged state to the released state.

[Example 1]
FIG. 1 is a schematic system diagram showing an automatic transmission according to a first embodiment. A clutch 2 is connected to the engine output shaft of the engine 1. The clutch 2 is a dry clutch, and the position of the clutch plate is controlled by the clutch actuator 2a. The clutch actuator 2a controls the position of the clutch piston that presses the clutch plate in accordance with the requested torque transmission capacity, and performs slip control for transmitting torque while allowing relative rotation of the clutch 2, and relative rotation of the clutch 2. Perform full fastening control that is not allowed. The clutch actuator 2a has a piston stroke sensor 11 that detects the stroke position of the clutch piston, and controls the torque transmission capacity based on the detected stroke position.

  Connected to the output side of the clutch 2 is an automatic transmission 3 that shifts the input rotation and outputs it to the drive wheels 4. The automatic transmission 3 has a first shaft 3a connected to the automatic transmission side of the clutch 2 and a second shaft 3b arranged in parallel with the first shaft 3a. On the 1st shaft 3a, it has the 1st speed drive gear 31 and the 2nd speed drive gear 32 supported so that relative rotation with respect to the 1st shaft 3a was possible. On the second shaft 3b, there are a first speed driven gear 33 fixed to the second shaft 3b and rotating integrally with the second shaft 3b, and a second speed driven gear 34. Each driven gear always meshes with each drive gear. Although not shown in the drawings, when configuring a forward four-speed automatic transmission, a third-speed drive gear, a third-speed driven gear, a fourth-speed drive gear, and a fourth-speed driven gear may be mounted similarly to the first-speed and second-speed. , Not specifically mentioned.

  A first dog 31 a extending in the axial direction is provided on a side surface of the first-speed drive gear 31. A side surface of the second drive gear 32 has a second dog 32a extending in the axial direction. The first speed drive gear 31 and the second speed drive gear 32 have first and second dog clutch mechanisms. The first dog clutch mechanism has a first clutch ring 311 that is fixedly installed on the first shaft 3 a and meshes with the first shift fork 310 so as to be relatively rotatable. Similarly, the second dog clutch mechanism also has a second clutch ring 321.

  The first clutch ring 311 is a disc-like member that can be applied to the first shift fork 310 while being held rotatably relative to the first shift fork 310. The first clutch ring 311 has a first clutch ring dog 311 a extending in the axial direction of the side surface facing the first-speed drive gear 31. Similarly, the second clutch ring 321 is a disk-shaped member that can be applied to the second shift fork 320 and an axial force while being held rotatably relative to the second shift fork 320. The second clutch ring 321 has a second clutch ring dog 321 a extending in the axial direction of the side surface facing the second-speed drive gear 32.

  At the first speed, the first shift fork 310 is moved to the right side in FIG. 1, the first clutch ring 311 is moved to the right side, and the first clutch ring dog 311a and the first dog 31a of the first speed drive gear 31 are moved. Engage to achieve 1st gear. During the upshift from the first speed to the second speed, the first shift fork 310 is moved to the left in FIG. 1 to release the engagement between the first clutch ring dog 311a and the first dog 31a, and the second shift. By moving the fork 320 to the right side in FIG. 1, the second clutch ring dog 321a and the second dog 32a are engaged with each other to achieve the second speed.

  The shift actuator 5 is configured to be able to move the first shift fork 310 and the second shift fork 320 in the axial direction. The shift actuator 5 has a shift drum 50 having shift grooves 51 and 52 that engage with the shift forks 310 and 320 on the outer periphery. The shift grooves 51 and 52 are formed to be movable in the axial direction of the shift forks 310 and 320 as the shift drum 50 rotates, and the shift motor 53 controls the rotational position of the shift drum 50 to change the speed. Do.

  The transmission controller 30 includes an engine speed sensor 10 that detects the engine speed, a first rotation angle sensor 12 that detects the rotation angle of the first shaft 3a, and a shift that detects the stroke positions of the shift forks 310 and 320. Stroke sensor 13, current sensor 14 for detecting the current value of shift motor 53, second rotation angle sensor 15 for detecting the rotation angle of second shaft 3b, and shift for selecting the P, R, N, and D ranges A desired gear position is determined based on the shift signal of the lever 7, and the drive current Is is output to the shift motor 53 of the shift actuator 5. Further, the transmission controller 30 stores the relative rotation angle of each dog clutch based on the storage unit 30a that stores the initial value of the relative rotation angle at each shift stage, and the stored relative rotation angle initial value and the gear ratio for each shift stage. A relative rotation angle calculation unit 30b to be calculated; and a reset unit 30c that performs a calculation of the relative rotation angle again after the dog clutch is completely engaged when a deviation occurs between the calculated relative rotation angle and the actual relative rotation angle. Have.

  Here, a problem when the dog clutch is engaged will be described. The first clutch ring dog 311a and the first dog 31a (hereinafter also referred to as both dogs) have a plurality of dog teeth arranged at equal positions on the circumference, and a recess formed between the dog teeth. When both dogs approach the axial direction and the dog teeth of one dog enter the recess of the other dog, the dog teeth are alternately arranged on the circumference. Thereby, torque is transmitted from one dog to the other dog. At this time, even if one dog tooth and the other dog tooth are close to each other on the circumference, the dog teeth interfere with each other and cannot approach the axial direction. If it does so, both dog teeth cannot be located in a line by turns and a dog clutch cannot be fastened. This state is referred to as an inactive state. In order to avoid the incompletion state and mesh the dog teeth, it is possible to detect the relative angle of the dog teeth and mesh at a relative rotation angle shifted by the circumferential thickness of the dog teeth.

  However, if sensors for detecting the rotation angle are provided for all the dog teeth, it is necessary to provide two sensors for one gear position, which may increase the cost due to an increase in the number of sensors. Therefore, in the first embodiment, the relative rotation angle is detected based on the rotation angles detected from the two sensors, the first rotation angle sensor 12 and the second rotation angle sensor 15.

  FIG. 2 is a schematic diagram illustrating the engaged / released state of the dog clutch according to the first embodiment. As shown in FIG. 2A, when the first clutch ring dog 311a and the first dog 31a are engaged with each other, there is a relative rotation angle corresponding to the tooth thickness θd in the circumferential direction of the dog teeth. A pitch angle representing an interval between adjacent dog teeth is θp. Also, as shown in FIG. 2B, the relative rotation angle when the first clutch ring dog 311a and the first dog 31a are released is defined as a first relative rotation angle θ1.

FIG. 3 is a time chart showing a cumulative rotation angle change when the dog clutch according to the first embodiment shifts from the engaged state to the released state. When both dogs are engaged at the first speed, the first relative rotation angle θ1 is constant at the tooth thickness θd in the circumferential direction of the dog teeth. Thereafter, when the first clutch ring dog 311a and the first dog 31a are released, the first clutch ring 311 is defined by the rotation angle of the first shaft 3a, and the first drive gear 31 is rotated by the rotation angle of the second shaft 3b. Stipulated in Accordingly, the gear ratio of the first gear is i1, the first cumulative rotation angle obtained by accumulating the rotation angle of the first shaft 3a is Σθin, and the second cumulative rotation angle obtained by accumulating the rotation angle of the second shaft 3b is Σθout. The first relative rotation angle θ1 when the dog clutch is released from the speed has the following relationship.
θ1 = (Σθin−Σθout × i1) mod (θp) + θd
Here, mod is an operator that calculates the remainder when dividing by an arbitrary number. The difference is divided by the pitch angle θp in order to know the relative angle in the relationship between the dog teeth, not the absolute relative angle. If the value corresponds to an integral multiple of the pitch angle, May be removed.

From the above, the relative rotation angle of both dog teeth can be detected even after the dog clutch is shifted from the engaged state to the released state. Here, the initial value of the relative rotation angle of the dog clutch in each gear when the gears of all the gears are assembled to the automatic transmission is stored in the storage unit 30a. Therefore, the relative rotation angle of the dog clutch can be calculated at all gear positions. For example, if the initial value of the relative rotation angle of the second gear is θd2, the gear ratio of the second gear is i2, and the relative rotation angle θ2 of the second gear dog clutch is
θ2 = (Σθin−Σθout × i2) mod (θp) + θd2
It is represented by That is, the relative rotation angle can be defined by the gear ratio of each shift stage and the relative rotation angle initial value.

  Here, if the relative angle of both dog teeth is between θd and θp, it is possible to enter the dog clutch when it is engaged and to avoid a state of failure. Therefore, for example, when upshifting from the first speed to the second speed, the engagement of the first speed dog clutch is released, and the second shift fork 320 is changed while the relative rotational angle θ2 of both the second speed dog clutches changes from θd to θp. By operating the shift actuator 5 so as to complete the movement, it is possible to realize an upshift that avoids an incompletion state. Since the shift fork requires a predetermined time, it is desirable to start the shift fork at a predetermined timing based on the relative rotation angle change rate and the rotation speed of the shift motor 53.

  On the other hand, the accumulated rotation angle may be shifted due to the detection accuracy problem of the first rotation angle sensor 12 and the second rotation angle sensor 15 and the rotation when the rotation angle sensors 12 and 15 do not detect the rotation angle. . In that case, in the reset unit 30c, after the dog clutch is once completely engaged, the initial value of the relative rotation angle is set to θd, and the calculation based on the cumulative rotation angle is performed from the time when the dog clutch is released. Can be detected.

As described above, the effects listed below are obtained in the first embodiment.
(1) a first speed drive gear 31 (first gear) supported on the first shaft 3a so as to be relatively rotatable;
A first-speed driven gear 33 (second gear) that is fixed to the second shaft 3b and constantly meshes with the first-speed drive gear 31 to become the first speed (predetermined gear ratio);
A first clutch ring 311 (clutch ring) having a first clutch ring dog 311a (clutch ring dog) engaged with the first dog 31a (dog of the first gear) by movement toward the axial meshing side;
A shift actuator that controls a power transmission state in which the first clutch ring dog 311a is moved in the axial direction to mesh with the first dog 31a and a power non-transmission state in which the first clutch ring dog 311a and the first dog 31a are released. 5 (actuator),
A first rotation angle sensor 12 for detecting the rotation angle of the first shaft 3a;
A second rotation angle sensor 15 for detecting the rotation angle of the second shaft 3b;
The gear ratio of the first speed is set to the first cumulative rotation angle Σθin that accumulates the rotation angles detected by the first rotation angle sensor 12 and the cumulative rotation angle Σθout that accumulates the rotation angles detected by the second rotation angle sensor 15. A relative rotation angle calculation unit 30b (controller) that calculates the relative rotation angle θ1 based on the multiplied second accumulated rotation angle and the initial value θd of the relative rotation angle between the first dog 31a and the first clutch ring dog 311a. ) And.
Therefore, the relative rotation angle of each dog clutch can be detected by two sensors, and the cost can be suppressed.

  (2) The storage unit 30a stores in advance relative rotation angle initial values at a plurality of shift speeds. Therefore, the relative rotation angle can be calculated before the dog teeth are engaged with each other.

(3) The automatic transmission is a multi-stage transmission having a plurality of shift stages, and the relative rotation angle calculation unit 30b calculates the relative rotation angles of the dog and the clutch ring dog at the plurality of shift stages.
Therefore, it becomes possible to detect the relative rotation angle of the dog clutch at all the shift speeds, and stable engagement can be achieved by controlling the operation timing of the shift actuator 5 at the time of shifting.

(4) The relative rotation angle calculation unit 30b updates the initial value of the relative rotation angle based on the circumferential tooth thickness of the first dog 31a when the first dog 31a and the first clutch ring dog 311a are engaged. .
That is, when both dogs mesh with each other, the relative rotation angle becomes the tooth thickness θd. Therefore, by calculating the cumulative rotation angle when released from this state, the relative rotation angle θ1 can be accurately calculated again even if the calculated value becomes unstable in the middle.

(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 drive gear that is a relative rotating body is arranged on the first shaft 3a, and a dog clutch mechanism that can selectively fix the drive gear to the first shaft 3a is provided. The first shaft 3a is not limited to be provided on the second shaft 3b, or may be set to both the first shaft 3a and the second shaft 3b in combination.
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.
Moreover, although the example which mounted the engine which is an internal combustion engine as a power source was shown in the Example, this invention is applicable also to the hybrid vehicle which uses a drive motor and an engine and a motor together as a power source.

DESCRIPTION OF SYMBOLS 1 Engine 2 Clutch 3 Automatic transmission 3a 1st shaft 3b 2nd shaft 4 Drive wheel 5 Shift actuator 12 1st rotation angle sensor 13 Shift stroke sensor 15 2nd rotation angle sensor 30 Transmission controller 30a Memory | storage part 30b Relative rotation angle calculation Part 30c reset part 31 first speed drive gear 31a first dog 33 first speed driven gear 50 shift drum 53 shift motor 310 first shift fork 311 first clutch ring 311a first clutch ring dog

Claims (4)

A first gear fixed to the first shaft or supported so as to be relatively rotatable;
A second gear fixed to the second shaft or supported so as to be relatively rotatable and having a predetermined gear ratio by always meshing with the first gear;
A clutch ring having a clutch ring dog that meshes with the dog of the first gear by movement toward the axial meshing side;
An actuator for controlling a power transmission state in which the clutch ring dog is moved in the axial direction and meshed with the dog, and a power non-transmission state in which the clutch ring dog and the dog are released;
A first rotation angle sensor for detecting a rotation angle of the first shaft;
A second rotation angle sensor for detecting a rotation angle of the second shaft;
A first cumulative rotation angle obtained by accumulating the rotation angle detected by the first rotation angle sensor and a rotation angle obtained by accumulating the rotation angle detected by the second rotation angle sensor are multiplied by the predetermined gear ratio. A controller that calculates the relative rotation angle based on the cumulative rotation angle of the first and the initial value of the relative rotation angle of the dog and the clutch ring dog,
An automatic transmission characterized by comprising: The automatic transmission according to claim 1, wherein
The automatic transmission, wherein the controller stores an initial value of the relative rotation angle in advance. The automatic transmission according to claim 1 or 2,
The automatic transmission is a multi-stage transmission having a plurality of shift stages,
The automatic transmission is characterized in that the controller calculates a relative rotation angle of the dog and the clutch ring dog at the plurality of shift speeds. The automatic transmission according to any one of claims 1 to 3,
The automatic transmission is characterized in that the controller updates the initial value based on a circumferential tooth thickness of the dog when the dog and the clutch ring dog are engaged with each other.

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