JP2017008961A - Dog clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dog clutch enabling coupling without repetitively performing coupling operation.SOLUTION: In a dog clutch, when a coupling command for moving a second dog to an axial engagement side toward an axial engagement position is output to an actuator, the movement of the second dog to the axial engagement side is stopped on an axial release side with respect to the axial engagement position, stops the coupling command, and re-outputs the coupling command to the actuator on the basis of the states of first and second dogs at the time when the movement of the second dog is stopped.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a dog clutch that is fastened by meshing dog teeth.

  In Patent Document 1, when switching from a two-wheel drive to a four-wheel drive by engaging a dog clutch, when detecting a state where the dog clutch is not engaged, the shift member is temporarily returned to the release position and moved again to the engagement position. Thus, a control for engaging the dog clutch is disclosed.

Japanese Patent Laid-Open No. 2002-264685

However, there is no guarantee that the dog clutch is engaged by the re-engagement operation, and there is a problem that if the relative rotational speed decreases while the engagement operation is repeated, the synchronization timing cannot be obtained and the engagement cannot be established.
The objective of this invention is providing the dog clutch which can be fastened without repeating fastening operation many times.

In order to achieve the above object, in the dog clutch of the present invention, the first dog supported by the first rotating body so as to be relatively rotatable,
A second dog which is supported by the first rotating body so as to be movable in the axial direction and meshes with the first dog by movement toward the axial meshing side;
An actuator for moving the second dog in the axial direction;
A control unit for controlling the actuator;
With
When the control unit outputs a fastening command for moving the second dog toward the axial meshing position toward the axial meshing side to the actuator, the control unit moves the second dog toward the axial meshing side. Is stopped on the axial release side from the axial meshing position, the fastening command is stopped, and the actuator is based on the state of the first and second dogs when the movement of the second dog is stopped. The fastening command is output again.

  That is, by outputting a second engagement command based on the state when the first dog and the second dog are not meshed, the dog clutch can be reliably engaged and the dog clutch can be engaged without repeating the engagement operation many times. Can be concluded.

1 is a schematic system diagram illustrating an automatic transmission according to a first embodiment. FIG. 3 is a schematic diagram illustrating a dog shape according to the first embodiment. FIG. 3 is a schematic diagram illustrating a relationship between dog teeth during a fastening operation according to the first embodiment. It is the schematic at the time of verifying with the dog clutch provided with four dog teeth instead of the six dog teeth of Example 1. FIG. 6 is a flowchart illustrating a dog clutch engagement control process at the time of ND selection according to the first embodiment. 6 is a time chart showing control at the time of selection from the N range to the D range when the vehicle is stopped in the first embodiment.

[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 side surface of the first drive gear 31 has a first dog 31a extending in the axial direction. 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-speed 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-speed clutch ring dog 321 a that extends in the axial direction on 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, the first speed clutch ring dog 311a and the first dog 31a of the first speed drive gear 31 are To achieve the first gear. During the upshift from the first speed to the second speed, the first shift fork 310 is moved to the left side in FIG. 1 to release the meshing between the first speed clutch ring dog 311a and the first dog 31a, By moving the shift fork 320 to the right in FIG. 1, the second-speed clutch ring dog 321a and the second dog 32a are meshed 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, an input speed sensor 12 that detects the speed of the first shaft 3a, and a shift stroke that detects the stroke positions of the shift forks 310 and 320. The sensor 13, the current sensor 14 for detecting the current value of the shift motor 53, the output rotational speed sensor 15 for detecting the rotational speed of the second shaft 3b, and the shift lever 7 for selecting the P, R, N, D range Based on the shift signal, a desired shift speed is determined, and a drive current Is, which is a fastening command, is output to the shift motor 53 of the shift actuator 5.

  Here, a problem when the dog clutch is engaged will be described. The first-speed 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.

  When the fastening operation is performed to bring both dogs closer to the axial direction while the first shaft 3a or the second shaft 3b is rotating, relative rotation occurs between the first-speed clutch ring dog 311a and the first shaft 3a. Therefore, even if a temporary entry failure occurs, because the relative angle of both dogs changes, for example, when a failure failure is detected, by performing another fastening operation and repeating until the fastening is completed, Both dogs will eventually mesh. However, even if the fastening operation is repeated in the dark clouds, there is no guarantee that the fastening operation is performed when the relative angle is in an appropriate relationship. Further, when the clutch 2 is engaged when the vehicle is stopped and the first shaft 3a is rotated together with the engine and each dog is released from the N range to the D range, the clutch 2 is released and the first shaft is released. It is necessary to fasten the first speed clutch ring dog 311a and the first dog 33a during inertial rotation of 3a. At this time, if the fastening operation is repeated, inertial rotation is reduced due to an increase in friction, and there is a problem that the relative angle between the two dogs cannot be shifted and the incompletion state cannot be eliminated. Therefore, in the first embodiment, when the non-entering state is detected, the fastening operation is performed again based on the rotation state of the dog when the non-entering state is detected.

  Here, the shape of the dog will be described. For example, if a high-precision rotation angle sensor such as a resolver is provided in each dog and the position of the dog tooth is always grasped, no entry failure occurs. However, if such expensive sensors are individually installed, the cost increases. Therefore, from the positional relationship between the dog teeth when a non-entry state occurs, the shape of the dog that reliably meshes with the dog teeth when the movement of the predetermined relative angle occurs was examined.

  FIG. 2 is a schematic diagram showing the dog shape of the first embodiment. Each dog of the first embodiment has six dog teeth, and the dog teeth are evenly arranged on the circumference when viewed from the rotation axis direction. The arrangement angle of the dog teeth on the circumference, the rotation angle θ1 occupied by the dog teeth, and the rotation angle θ2 occupied between the dog teeth (hereinafter referred to as backlash) are the same for each dog. . In other words, the dog tooth occupation rate Pθ1 is represented by θ1 / 360, and the backlash occupation rate Pθ2 is represented by θ2 / 360. In the description, the dog teeth of the first dog 31a are referred to as first dog teeth d1, and the dog teeth of the first-speed clutch ring dog 311a are referred to as second dog teeth d2.

  FIG. 3 is a schematic diagram illustrating the relationship of the dog teeth during the fastening operation of the first embodiment. In FIG. 3, only one first dog tooth d1 of the first dog 31a is shown in the schematic view of the first-speed clutch ring dog 311a as viewed from the front, but the same relationship applies to all the second dog teeth d2. Has occurred. FIG. 3 shows the relative relationship when the first-speed clutch ring dog 311a rotates clockwise with the first dog 31a fixed. FIG. 3A shows a state in which the first dog teeth d1 cannot enter at the end portion on the counterclockwise side of the second dog teeth d2 (end portion on the front side in the rotation direction). From this state, as shown in FIG. 3B, an angle obtained by adding the rotation angle of one tooth of the first dog tooth d1 and the rotation angle of one tooth of the second dog tooth d2 (hereinafter referred to as an avoidance angle). When the relative angle is generated, it is desirable that the first dog tooth d1 passes through the second dog tooth d2 to be surely positioned at the backlash. Next, FIG.3 (c) represents the state which the 1st dog tooth d1 did not enter at the edge part (clockwise direction inner side edge part) of the 2nd dog tooth d2 in the clockwise direction. From this state, as shown in FIG. 3 (d), even if the relative angle is generated by the avoidance angle, the first dog tooth d1 does not reach the next second dog tooth d2, and is surely positioned in the backlash. Is desirable.

As a result of earnest examination of the occupation ratio Pθ1 that is the ratio of the rotation angle θ1 to the circumference and the ratio Pθ2 that is the ratio of the rotation angle θ2 to the circumference that satisfies the above relationship, Pθ1 is 25% or less and Pθ2 is 75% or more. I found out that In other words, from Pθ1 ≦ 0.25 and Pθ2 ≧ 0.75,
(Avoidance conditions)
Pθ1 / Pθ2 ≦ 1/3
It was found that if the relative relationship of the avoidance angle occurs after detecting the incompletion state, the incompletion state can be reliably avoided. FIG. 4 is a schematic diagram in the case of verification with a dog clutch provided with four dog teeth instead of the six dog teeth of the first embodiment. It has been found that the same avoidance condition is established even in a configuration having four dog teeth as shown in FIG. In addition, when four dog teeth are provided, for example, even when the configuration includes eight dog teeth by adding a dog tooth having a low tooth height to the backlash, when four dog teeth are provided substantially And there is no difference. In addition to the four dog teeth, any number of teeth may be used as long as the avoidance condition is satisfied.

FIG. 5 is a flowchart showing a dog clutch engagement control process at the time of ND selection according to the first embodiment.
In step 1, it is determined whether or not a selection from the N range to the D range (hereinafter referred to as ND selection) has been performed. If not, this control flow is terminated and the ND selection is completed. If it is determined, the process proceeds to step S2.
In step S2, the clutch 2 is released.
In step S3, a fastening command for moving the first-speed clutch ring dog 311a toward the axial meshing position toward the axial meshing side is output to the shift motor 53.
In step S4, it is determined whether or not the drive current Is of the shift motor 53 is greater than or equal to the input current I1 that is greater than a predetermined current generated by the rotation of the shift drum 50. Then, the present control flow is terminated, and otherwise, it is determined that there is a possibility of no entry, and the process proceeds to step S5. In other words, if the shift fork cannot enter, the shift drum 50 cannot rotate because the shift fork cannot move in the axial direction. Then, even if it tries to move to the rotational position corresponding to the desired gear position, the drive load of the shift motor 53 increases, and the drive current Is increases. Utilization of this characteristic is used to determine whether the drive current Is is present.

In step S5, the engagement command is stopped, the shift motor 53 is rotated in the reverse direction, and the first-speed clutch ring dog 311a is returned to the position where it is not in contact with the first dog 33a. Thus, by making both dogs into a non-contact state, the fall of the inertia rotation of the 1st shaft 3a is suppressed.
In step S6, the rotational angular velocity (relative angular velocity) of the first-speed clutch ring dog 311a is calculated based on the number of rotations of the first shaft 3a when the non-enter state is detected in step S4. In the first embodiment, since it is assumed that the dog clutch is engaged while the vehicle is stopped, the rotation of the second shaft 3b and the first dog 31a is stopped. Therefore, the rotational angular velocity of the first-speed clutch ring dog 311a matches the relative angular velocity with the first dog 31a. When both shafts are rotating, both the rotational speed of the first shaft 3a and the rotational speed of the second shaft 3b may be detected, and the relative angular velocity may be detected from the relative rotational speed.

  In step S7, an avoidance angle (predetermined relative angle) at which the first-speed clutch ring dog 311a and the first dog 31a can mesh with each other from the time when the first-speed clutch ring dog 311a stops moving is detected. When the time obtained by dividing the angle) by the rotational angular velocity of the first-speed clutch ring dog 311a, which is a relative angular velocity, elapses, the engagement command is output again.

FIG. 6 is a time chart showing the control at the time of selection from the N range to the D range when the vehicle is stopped according to the first embodiment. The engine 1 is in an operating state, the vehicle is stopped, and the clutch 2 is in a fully engaged state.
At time t1, when the driver operates the shift lever 7 from the N range to the D range, the clutch 2 is released to prepare for the start. Thereby, the rotation speed of the first shaft 3a gradually decreases while inertially rotating.

At time t2, the shift motor 53 is driven and the shift drum 50 rotates, whereby the first shift fork 310 starts a stroke. At this time, if no improper entry occurs, the shift drum 50 rotates smoothly, and the drive current Is does not increase to the improper current I1. However, if there is no entry, the first shift fork 310 cannot make a sufficient stroke, and the shift drum 50 cannot rotate smoothly, so that the drive current Is starts to rise.
When the drive current Is enters at time t3 and exceeds the non-current I1, the shift drum 50 is once rotated in the reverse direction. At this time, the relative rotation angle between the first speed clutch ring dog 311a and the first dog 31a is calculated, the time for achieving the avoidance angle is calculated, and the timer starts counting up.
At time t4, when the count value of the timer has exceeded the time for achieving the avoidance angle, the engagement command is output again, and the shift drum 50 is rotated to the engagement side. At this time, the first-speed clutch ring dog 311a and the first dog 31a rotate relative to each other by an avoidance angle, and therefore do not enter.
When the first speed clutch ring dog 311a meshes with the first dog 31a at time t5, the shift stroke amount Str enters and exceeds the non-stroke amount Str0, and the shift to the first speed can be completed. At time t6, when the rotation of the shift drum 50 is completely rotated to the target position, the drive current Is is stopped.

As described above, the effects listed below are obtained in the first embodiment.
(1) A first dog 31a supported to be rotatable relative to the first shaft 3a (first rotating body), and supported to be movable in the axial direction on the first shaft 3a. 1st clutch ring dog 311a (second dog) meshing with 1 dog 31a, shift actuator 5 (actuator) for moving the first speed clutch ring dog 311a in the axial direction, and transmission controller for controlling shift actuator 5 30 (control unit), and the transmission controller 30 sends a fastening command that is a command to move the first-speed clutch ring dog 311a toward the axial meshing position toward the axial meshing position. When output, the movement of the first-speed clutch ring dog 311a to the axial meshing side stops on the axial release side from the axial meshing position. Stops the engagement command and re-outputs the engagement command to the shift actuator 5 based on the state of the first dog 31a and the first speed clutch ring dog 311a when the movement of the first speed clutch ring dog 311a is stopped. It was.
That is, the first dog 31a and the first-speed clutch ring dog 311a can be reliably engaged by outputting a second engagement command based on the non-engagement state that is a state when the first-speed clutch ring dog 311a is not engaged. The dog clutch can be fastened without repeating the operation many times.

(2) The states of the first dog 31a and the first speed clutch ring dog 311a are the relative angular velocities of the first dog 31a and the first speed clutch ring dog 311a.
Therefore, it is possible to estimate when the state in which the incompletion state is eliminated occurs.

(3) The transmission controller 30 avoids an angle (predetermined relative angle) at which the first dog 31a and the first gear clutch ring dog 311a can mesh with each other after the movement of the first gear clutch ring dog 311a stops. When the time divided by the relative angular velocity at the detection of the non-entering state has elapsed, the fastening command is re-output.
Therefore, the dog clutch can be fastened at a timing at which it is possible to reliably enter and avoid a non-state without using a highly accurate rotation angle sensor such as a resolver.

(4) The avoidance angle is the sum of the rotation angle occupied by one dog tooth on the circumference of the first dog 31a and the rotation angle occupied by one dog tooth on the circumference of the first-speed clutch ring dog 311a. is there.
In the non-entering state, when the first-speed clutch ring dog 311a is moved in the axial direction, the dog teeth of the first dog 31a and the dog teeth of the first-speed clutch ring dog 311a enter at the front end in the rotational direction. From a non-conforming state, it becomes a non-entering state at the end in the rotational direction, and the non-entering state can occur over a wide range. Therefore, if the relative rotation angle is generated by the sum of the rotation angles occupied by the two dog teeth, a state where the dog teeth and the backlash face each other is obtained, and the incompletion state can be reliably avoided.

(5) The first occupancy Pθ1 occupied by the dog teeth with respect to the circumference on the circumference of the first dog 31a and the first-speed clutch ring dog 311a is the circumference between the dog teeth and the dog teeth. The value divided by the occupied second occupation ratio Pθ2 is 1/3 or less.
Therefore, when the relative rotation corresponding to the avoidance angle occurs after occurrence of the non-entering state, a state where the dog teeth and the backlash face each other is obtained, and the non-entering state can be avoided reliably.

(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, the present invention is applied at the time of ND selection. However, the present invention can be applied to any gear position as long as the speed is changed. In this case, it is only necessary to include a sensor capable of estimating the relative rotational angular velocity, and it is not necessary to detect each rotational speed with high accuracy. In the first embodiment, a drive gear that is a relative rotating body is disposed 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 2a Clutch actuator 3 Automatic transmission 3a 1st shaft 3b 2nd shaft 4 Drive wheel 5 Shift actuator 7 Shift lever 10 Engine speed sensor 12 Input speed sensor 14 Current sensor 15 Output speed sensor 30 Transmission controller 31 1st speed drive gear 31a 1st dog 32 2nd speed drive gear 32a 2nd dog 33 1st speed driven gear 34 2nd speed driven gear 50 Shift drum 51, 52 Shift groove 53 Shifting motor 310 1st shift fork 311 1st clutch ring 311a 1 High speed clutch ring dog 320 Second shift fork 321 Second clutch ring 321a Second speed clutch ring dog

Claims (5)

A first dog supported by the first rotating body so as to be relatively rotatable;
A second dog which is supported by the first rotating body so as to be movable in the axial direction and meshes with the first dog by movement toward the axial meshing side;
An actuator for moving the second dog in the axial direction;
A control unit for controlling the actuator;
With
When the controller outputs a command to the actuator to move the second dog toward the axial meshing position toward the axial meshing side, the second dog moves to the axial meshing side. When stopping on the axial release side from the axial meshing position, the command is stopped, and the actuator is moved to the actuator based on the state of the first and second dogs when the movement of the second dog is stopped. A dog clutch that re-outputs a command. The dog clutch according to claim 1,
The dog clutch characterized in that the state of the first and second dogs is a relative angular velocity of the first dog and the second dog. The dog clutch according to claim 2,
The control unit is configured such that when a time obtained by dividing a predetermined relative angle at which the first dog and the second dog can be engaged with each other by the relative angular velocity has elapsed since the movement of the second dog is stopped. A dog clutch that re-outputs a command. The dog clutch according to claim 3,
The predetermined relative angle is a sum of a rotation angle occupied by one dog tooth on the circumference of the first dog and a rotation angle occupied by one dog tooth on the circumference of the second dog. A dog clutch. The dog clutch according to any one of claims 1 to 4,
The first occupation ratio occupied by the dog teeth relative to the circumference on the circumference of the first and second dogs is divided by the second occupation ratio occupied between the dog teeth and the dog teeth relative to the circumference. A dog clutch having a value of 1/3 or less.

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