JP2017159763A - Transfer device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the breakage of a fork or the like when making a gear piece and a sleeve geared with each other, in a transfer device for performing torque distribution control and range changeover control by using a common motor.SOLUTION: In a transfer device, the pressing of a clutch at torque distribution control, and the moving of a fork in range changeover control for establishing a low-speed range or a high-speed range by making teeth of a sleeve which slides by the movement of the fork and a high-gear piece or a low-gear piece geared with each other are performed by using a common motor. The transfer device comprises a transfer ECU which performs position control for driving the motor so that a position of the sleeve and a target position coincide with each other at the range changeover control. When a chamfer of the teeth of the sleeve is located in a position in which the chamfer is at least partially overlapped in an axial direction on a chamfer of the gear piece which is liable to be geared with the sleeve out of the high-gear piece and the low-gear piece, the transfer ECU performs current control for controlling a drive current of the motor.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a transfer device, and more particularly to a transfer device including a clutch that distributes torque between a main drive wheel and a sub drive wheel, and a range switching mechanism that switches between a high speed range and a low speed range.

  2. Description of the Related Art Conventionally, there is known a transfer device that is provided between a main drive wheel and a sub drive wheel and transmits a part of driving force transmitted to the main drive wheel to the sub drive wheel. Such transfer devices include a clutch that distributes torque between the main drive wheel and the sub drive wheel, a range switching mechanism that establishes a high speed range that is used during normal driving and a low speed range that is used during off-road driving, and the like. is there.

  For example, in Patent Document 1, the frictional force of a wet multi-plate clutch is controlled by an actuator, and a differential limiting mechanism that distributes the torque of the front and rear wheels and the fork controlled by the shift actuator slide in the axial direction. A transfer device is disclosed that includes both a range switching mechanism that switches between a high speed range and a low speed range by meshing the teeth of a sleeve with a high gear piece or a low gear piece that are arranged apart in the axial direction.

JP2013-252814A

  By the way, in order to reduce the manufacturing cost and the vehicle body weight, the actuator for controlling the frictional force of the wet multi-plate clutch and the shift actuator for controlling the movement of the fork are not separated as in the above-mentioned Patent Document 1. For example, it is preferable to perform torque distribution by the clutch and range switching by the fork using a common motor.

  However, in such a configuration, the movement of the fork is normally performed by position control that drives the motor so that the position of the sleeve matches the target position, and the load ( For example, several tens of thousands N) and a load (for example, several hundred N) necessary for switching the range are greatly different from each other, and there are the following problems.

  That is, chamfered portions called chamfers are formed on the axial tooth tips of the sleeve teeth, and the axial tooth tips of the high gear piece and the low gear piece. Are designed to mesh smoothly. If such a chamfer functions properly, the sleeve is smoothly slid by the movement of the fork and the pushing is completed, and the teeth of the sleeve engage with the high gear piece or the low gear piece.

  However, when the sleeve is slid by the movement of the fork, for example, when the apex of the chamfer on the sleeve teeth and the apex of the chamfer of the high gear piece or low gear piece (so-called per apex occurs) ), It becomes difficult to push even if the load is increased. Nevertheless, since position control is performed, the load from the motor increases to the order necessary for torque distribution. In other words, for example, a load of tens of thousands of N is applied to the fork or the like, which is the worst. In this case, the fork or the like may be damaged.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a high gear in a transfer device that uses a common motor for clutch pressing in torque distribution control and fork movement in range switching control. The object is to prevent breakage of the fork or the like when the piece or the low gear piece is engaged with the teeth of the sleeve.

  In order to achieve the above object, in the transfer device according to the present invention, two types of control for the motor are selectively used depending on the position of the sleeve during range switching.

  Specifically, the present invention relates to the pressing of the clutch in torque distribution control that distributes the torque between the main drive wheel and the sub drive wheel using the clutch, and the teeth of the sleeve that slides in the axial direction by the movement of the fork in the axial direction. A transfer device in which the movement of a fork in the range switching control that establishes a high speed range or a low speed range by meshing with a high gear piece or a low gear piece arranged apart from each other is performed using a common motor.

  The transfer device includes a control device that performs position control for driving the motor so that the position of the sleeve coincides with a target position at the time of the range switching control. When the chamfer is at a position at least partially overlapping with the chamfer of the gear piece to be engaged with the sleeve of the high gear piece and the low gear piece, current control for controlling the drive current of the motor is performed. It is comprised so that it may be comprised.

  According to this configuration, when the chamfer of the tooth of the sleeve is at a position at least partially overlapping with the chamfer of the gear piece to be engaged with the sleeve, in other words, the chamfer of the high gear piece or the low gear piece and the chamfer of the sleeve. , The sleeve is stopped, and current control is performed instead of position control. Therefore, damage to the fork or the like can be suppressed by appropriately controlling the drive current of the motor.

  In addition, when the gear piece to be engaged with the sleeve and the teeth of the sleeve do not overlap in the axial direction, or when the pushing is completed, in other words, when there is no possibility that the sleeve stops at a position other than the target position, Since the control is performed, the range can be switched quickly without limiting the motor drive current more than necessary.

  As described above, according to the transfer device of the present invention, when the high gear piece or the low gear piece meshes with the teeth of the sleeve, damage to the fork or the like can be suppressed.

It is a figure showing typically a vehicle carrying a transfer device concerning an embodiment of the present invention. It is a figure which shows a transfer apparatus typically. It is a figure which shows typically the positional relationship of the chamfer of a high gear piece and a low gear piece, and the chamfer of the tooth | gear of a sleeve. It is a flowchart which shows the control which a control apparatus performs. It is a timing chart which shows an example of the control which a control device performs.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram schematically showing a vehicle 1 equipped with a transfer device 4 according to the present embodiment. The vehicle 1 is basically a front engine / rear drive (FR drive), a two-wheel drive mode in which the driving force is transmitted only to the rear wheels 7L, 7R, and the front wheels 11L, 11R via the control clutch 18. This is a four-wheel drive vehicle that can be switched between a standby four-wheel drive mode that is also transmitted to a full-time four-wheel drive mode in which drive power is always transmitted to the rear wheels 7L and 7R and the front wheels 11L and 11R. As shown in FIG. 1, the vehicle 1 includes an engine 2, an automatic transmission 3, a transfer device 4, a rear propeller shaft 5, a rear differential 6, left and right rear wheels 7L and 7R, and a front propeller shaft 8. , A front differential 9, an ADD device 10, and left and right front wheels 11L and 11R.

  In the vehicle 1, the rotational driving force output from the engine 2 is shifted at a desired gear ratio in the automatic transmission 3 and then input to the input shaft 13 of the transfer device 4.

  The rotational driving force input to the transfer device 4 is transmitted to a power transmission path corresponding to the high speed range or the low speed range by a range switching mechanism 16 provided in the transfer device 4 and then output from the rear output shaft 14. . The rotational driving force output from the rear output shaft 14 is transmitted to the rear propeller shaft 5 and the left and right rear wheels 7L, 7R via the rear differential 6 that transmits power while appropriately applying differential rotation to the left and right rear wheels 7L, 7R. Is transmitted to. The left and right rear wheels 7L and 7R constitute main drive wheels that serve as drive wheels in the two-wheel drive mode, the standby four-wheel drive mode, and the full-time four-wheel drive mode.

  Further, part of the rotational driving force input to the transfer device 4 is output from the front output shaft 15. The rotational driving force output from the front output shaft 15 is transmitted to the front propeller shaft 8, the left and right front wheels 11 </ b> L and 11 </ b> R while appropriately rotating the front differential 9, and the left and right front wheels via the ADD device 10. 11L and 11R. The ADD device 10 is provided between the front differential 9 and the front wheel 11R, and includes a transmission state in which power is transmitted between the front propeller shaft 8 and the left and right front wheels 11L and 11R, and a cutoff state in which the power is cut off. It can be switched to. The left and right front wheels 11L and 11R serve as driven wheels in the two-wheel drive mode, and constitute auxiliary drive wheels that serve as drive wheels in the standby four-wheel drive mode and the full-time four-wheel drive mode.

  As shown in FIG. 2, the transfer device 4 includes a transfer ECU (Electronic Control Unit) 12, an input shaft 13, a rear output shaft 14, a front output shaft 15, a range switching mechanism 16, a transmission mechanism 17, A control clutch 18, a thrust generating mechanism 19, and a transfer case 21 that accommodates these are provided.

  The transfer ECU (control device) 12 includes, for example, a microcomputer including a CPU, a RAM, a ROM, an input / output interface, and the like. The output control of the engine 2, the shift control of the automatic transmission 3, the ADD device 10 It communicates with other ECUs (not shown) that perform switching control and the like. The transfer ECU 12 performs torque processing for controlling the torque distribution ratio between the rear wheels 7L and 7R and the front wheels 11L and 11R by performing signal processing in accordance with a program stored in the ROM in advance using the temporary storage function of the RAM. Various controls of the transfer device 4 such as control and range switching control for switching the power transmission path between the high speed range and the low speed range are executed.

  The input shaft 13, the rear output shaft 14 and the front output shaft 15 are rotatably supported by the transfer case 21 via rolling bearings (not shown). A rotational driving force is input to the input shaft 13 from the automatic transmission 3. The rear output shaft 14 is disposed coaxially with the input shaft 13 and outputs rotational driving force to the rear wheels 7L and 7R. The front output shaft 15 is disposed in parallel with the rear output shaft 14 and outputs a rotational driving force to the front wheels 11L and 11R.

  The range switching mechanism 16 includes a single pinion type planetary gear 22, a high gear piece 27, a low gear piece 28, a sleeve 29, a fork 30, and a fork shaft 31.

  The planetary gear 22 includes an internal gear ring gear 23 fixed to the transfer case 21 so as not to rotate, an external gear sun gear 24 connected to the input shaft 13 so as to be integrally rotatable, and the ring gear 23 and the sun gear 24. A plurality of pinion gears 25 that mesh with them, and a carrier 26 that rotatably supports the pinion gears 25 and that rotates in synchronization with the revolving operation of the pinion gears 25 are included.

  The high gear piece 27 is an internal gear integrally formed with the sun gear 24 and can rotate integrally with the input shaft 13. Thereby, the high gear piece 27 outputs the rotational driving force input from the input shaft 13 substantially as it is. On the other hand, the low gear piece 28 is an internal gear integrally formed with the carrier 26, and outputs a rotational driving force decelerated by the planetary gear 22 after being input from the input shaft 13.

  The sleeve 29 is disposed outside the rear output shaft 14 and is spline-fitted with the rear output shaft 14, whereby the sleeve 29 can be moved relative to the rear output shaft 14 in the axial direction, and the rear output The shaft 14 and the shaft 14 can rotate together. The sleeve 29 is provided with external teeth 29 a that can mesh with the high gear piece 27 and the low gear piece 28.

  The fork shaft 31 is configured to slide in the axial direction by the thrust generating mechanism 19. The fork 30 connected to the fork shaft 31 is fitted in a groove provided in the sleeve 29 at the tip. When the fork shaft 31 slides, the fork 30 moves in the axial direction, whereby the sleeve 29 slides in the axial direction and takes a position where it engages with the high gear piece 27 and a position where it engages with the low gear piece 28. Yes. When the external teeth 29a of the sleeve 29 mesh with the high gear piece 27, a high speed range is established in which the rotational driving force input from the input shaft 13 is transmitted to the rear output shaft 14 substantially as it is. On the other hand, when the outer teeth 29a of the sleeve 29 mesh with the low gear piece 28, a low speed range is established in which the rotational driving force input from the input shaft 13 is decelerated by the planetary gear 22 and transmitted to the rear output shaft 14.

  The transmission mechanism 17 includes a drive gear 32, a driven gear 33, a drive chain 34, and a differential lock sleeve 35.

  The drive gear 32 is externally mounted on the rear output shaft 14 via a rolling bearing (not shown), and is connected to a drum 38 described later so as to be integrally rotatable. The driven gear 33 is formed integrally with the front output shaft 15. The drive chain 34 is wound around the drive gear 32 and the driven gear 33, and transmits the rotational driving force output from the drive gear 32 to the driven gear 33.

  The differential lock sleeve 35 is disposed between the sleeve 29 and the drive gear 32 outside the rear output shaft 14. The differential lock sleeve 35 is spline-fitted with the rear output shaft 14, thereby being capable of relative movement in the axial direction with respect to the rear output shaft 14 and being capable of rotating integrally with the rear output shaft 14. When the sleeve 29 engages with the low gear piece 28, the differential lock sleeve 35 is pushed by the sleeve 29 and fits into a fitting portion 32a provided on the drive gear 32, and is spline fitted to the drive gear 32. When it is engaged with the high gear piece 27, it is biased in the axial direction by springs 36 and 37 provided between the sleeve 29 and the drive gear 32, respectively, so as to come out of the fitting portion 32a. .

  With such a configuration, the drive gear 32 does not rotate even when the rear output shaft 14 rotates, the drive gear 32 rotates at a rotational speed different from the rear output shaft 14 as the drum 38 rotates, and the differential lock sleeve 35 is rotated. Via the rear output shaft 14.

  The control clutch 18 includes a substantially cylindrical drum 38 disposed outside the rear output shaft 14, a clutch plate 39, and a substantially cylindrical hub (not shown) connected to the rear output shaft 14 so as to be integrally rotatable. And a clutch disk 40 and a substantially cylindrical piston 41 disposed outside the rear output shaft 14.

  The control clutch 18 has a plurality of clutch plates 39 spline-fitted to the inner peripheral surface of the drum 38, and a clutch disc 40 sandwiched between the clutch plates 39 is spline-fitted to the outer peripheral surface of the hub. Torque is transmitted by friction-welding the clutch plate 39 and the clutch disc 40 with a piston 41 that moves in the direction. A thread groove is formed on the inner peripheral surface of the piston 41.

  The thrust generation mechanism 19 converts the rotational motion into a linear motion and applies axial thrust to the piston 41 of the control clutch 18 and the fork shaft 31 of the range switching mechanism 16. The transfer motor 20 and the worm gear 42 are provided with the thrust generation mechanism 19. A cylindrical screw shaft 43, a reduction gear 44, a ball 45, an arm 46, and an engagement mechanism 47.

  The transfer motor 20 is arranged such that the motor shaft is orthogonal to the shaft such as the rear output shaft 14. The cylindrical screw shaft 43 is disposed outside the rear output shaft 14 so as to be rotatable relative to the rear output shaft 14. The rotational driving force around the motor shaft output from the transfer motor 20 is converted into the rotational driving force around the rear output shaft 14 via the worm gear 42 and the reduction gear 44 provided on the screw shaft 43, and the screw shaft 43. Rotate.

  A ball 45 is interposed between the screw groove of the screw shaft 43 and the screw groove of the piston 41, and the screw shaft 43, the piston 41, and the ball 45 form a ball screw structure. Therefore, when the screw shaft 43 rotates, the rotational motion is converted into a linear motion, and the piston 41 moves along the rear output shaft 14 to release or fasten the clutch plate 39 and the clutch disc 40.

  Further, as the piston 41 moves in the axial direction of the rear output shaft 14, the arm 46 provided on the piston 41 moves in the axial direction of the fork shaft 31 disposed in parallel with the rear output shaft 14. The arm 46 is configured to engage with the fork shaft 31 via an engagement mechanism 47 provided on the fork shaft 31.

  When the piston 41 moves forward (moves to the left side in FIG. 1) and engages the clutch plate 39 and the clutch disc 40 (hereinafter also referred to as an engagement region), the engagement mechanism 47 moves between the arm 46 and the fork. While the shaft 31 is not engaged, the piston 41 moves backward (moves to the right in FIG. 1) to release the clutch plate 39 and the clutch disc 40 (hereinafter also referred to as a release region). 46 and the fork shaft 31 are engaged with each other. Thereby, in the transfer apparatus 4 of this embodiment, the range which switches a high speed range and a low speed range by the slide of the fork shaft 31 accompanying advance and reverse of the piston 41, although the common transfer motor 20 is used. The switching control and the torque distribution control for controlling the torque distribution ratio between the rear wheels 7L and 7R and the front wheels 11L and 11R are not synchronized by the engagement of the clutch plate 39 and the clutch disk 40 as the piston 41 moves forward. ing.

  As shown in FIG. 1, a dial 48 that can switch between a high speed range and a low speed range is provided in the vehicle 1. The dial 48 is connected to the transfer ECU 12 and outputs a signal corresponding to each range to the transfer ECU 12. The transfer ECU 12 performs position control for driving the transfer motor 20 so that the position of the sleeve 29 coincides with the target position in accordance with a signal corresponding to each range.

  In the vehicle 1 of the present embodiment configured as described above, when the dial 48 is operated and the high speed range is selected, the sleeve 29 is positioned on the condition that the vehicle speed is 0, etc. The transfer ECU 12 drives the transfer motor 20 to rotate in the forward direction so as to coincide with the position where the outer teeth 29a of the 29 and the high gear piece 27 mesh with each other. When the transfer motor 20 is driven to rotate forward, the piston 41 moves forward, and the fork shaft 31 slides forward (to the left in FIG. 1). As a result, when the fork 30 moves to the front side and the outer teeth 29a of the sleeve 29 mesh with the high gear piece 27, a high speed range is established, and the rotational driving force input from the input shaft 13 is applied to the rear output shaft 14 as it is. Communicated. The rotational driving force output from the rear output shaft 14 is transmitted to the left and right rear wheels 7L and 7R via the rear propeller shaft 5 and the rear differential 6. At this time, since the differential lock sleeve 35 is not fitted in the fitting portion 32a and the piston 41 is in the release region, the drive gear 32 does not rotate and the rotational driving force is not transmitted to the front wheels 11L and 11R. As a result, the two-wheel drive mode in the high speed range is established. In addition, in the two-wheel drive mode, if the ADD device 10 is shut off, the accompanying rotation of the front propeller shaft 8 and the like by the front wheels 11L and 11R stops, so that friction loss can be reduced and fuel efficiency can be improved. .

  In the two-wheel drive mode, for example, when idle rotation of the rear wheels 7L and 7R as drive wheels is detected by a wheel speed sensor (not shown), the position of the piston 41 corresponds to the target torque distribution ratio. The transfer ECU 12 further drives the transfer motor 20 to rotate forward so as to coincide with. When the transfer motor 20 is driven forward, the piston 41 moves forward, and the clutch plate 39 and the clutch disk 40 are fastened. Thus, when the piston 41 is in the fastening region, the arm 46 and the fork shaft 31 are not engaged and the sleeve 29 does not slide, so that the high speed range is maintained and the rotational driving force output from the rear output shaft 14 is maintained. Is transmitted to the left and right rear wheels 7L, 7R. Further, since the clutch plate 39 and the clutch disk 40 are fastened, the drive gear 32 rotates, and the drive chain 34, the driven gear 33, the front output shaft 15, the front propeller shaft 8, the front differential 9 and the ADD device 10 are passed through. The rotational driving force is also transmitted to the front wheels 11L and 11R. As a result, the standby four-wheel drive mode in the high speed range is established.

  On the other hand, when the dial 48 is operated from the two-wheel drive mode and the low speed range is selected, the transfer is performed so that the position of the sleeve 29 coincides with the position where the external gear 29a of the sleeve 29 and the low gear piece 28 mesh with each other. The ECU 12 reversely drives the transfer motor 20. When the transfer motor 20 is driven in reverse, the piston 41 moves backward, and the fork shaft 31 slides rearward (right side in FIG. 1). When the fork 30 moves to the rear side and the external teeth 29a of the sleeve 29 mesh with the low gear piece 28, the low speed range is established, and the rotational drive force input from the input shaft 13 is decelerated by the planetary gear 22, and then the rear output It is output from the shaft 14 and transmitted to the left and right rear wheels 7L, 7R. Further, since the differential lock sleeve 35 is fitted into the fitting portion 32a by the retraction of the sleeve 29, the drive gear 32 rotates integrally with the rear output shaft 14, and the rotational driving force is transmitted to the front wheels 11L and 11R. As a result, the full-time four-wheel drive mode in the low speed range is established.

  As described above, in the vehicle 1 of the present embodiment, the range switching control for switching the power transmission path between the high speed range and the low speed range, and the torque distribution control for controlling the torque distribution ratio between the rear wheels 7L and 7R and the front wheels 11L and 11R. Since the single transfer motor 20 is used, the manufacturing cost can be reduced, and the vehicle weight can be reduced to improve the fuel consumption.

  However, when a single transfer motor 20 is used, the transfer ECU 12 drives the transfer motor 20 by position control, and loads (for example, tens of thousands of N) and range switching necessary for torque distribution are changed. The following problems may occur due to a large deviation from the load (for example, several hundred N) necessary to perform.

  FIG. 3 schematically shows the positional relationship between the chamfer 57 of the high gear piece 27 and the chamfer 58 of the low gear piece 28 and the chamfer 59 of the external teeth 29a of the sleeve 29 (hereinafter also simply referred to as the chamfer 59 of the sleeve 29). FIG. The chamfers 57, 58, and 59 are chamfered portions formed so that the teeth can smoothly mesh with each other. If such chamfers 57, 58, 59 function properly, for example, the outer teeth 29a of the sleeve 29 slide smoothly from the (3) position to the (2) position in FIG. In the position (2) where the shoulder 57b of the chamfer 57 of the 27 and the shoulder 59b of the chamfer 59 of the sleeve 29 come into contact with each other, the separation of the outer teeth 29a of the sleeve 29 and the high gear piece 27 is completed in the position (1). To do. Similarly, the movement of the fork 30 causes the outer teeth 29a of the sleeve 29 to slide smoothly from the (4) position to the (5) position in FIG. 3, and the shoulder 58b of the chamfer 58 of the low gear piece 28 and the chamfer 59 of the sleeve 29 are moved. Pushing is completed at the position (5) where the shoulder 59b comes into contact, and the meshing between the outer teeth 29a of the sleeve 29 and the low gear piece 28 is completed at the position (6).

  However, when the sleeve 29 is slid by the movement of the fork 30, for example, the apex 59a of the chamfer 59 of the sleeve 29 abuts the apexes 57a and 58a of the chamfers 57 and 58 of the high gear piece 27 or the low gear piece 28 and the inclined surface. If the shoulder 59b of the chamfer 59 of the sleeve 29 abuts against the apexes 57a and 58a of the chamfers 57 and 58 of the high gear piece 27 or the low gear piece 28 or an inclined surface, it is difficult to separate even if the load is increased. It becomes. Nevertheless, since the position control is performed, the load by the transfer motor 20 rises to the order necessary for torque distribution, and in the worst case, the fork 30 and the like may be damaged.

  Therefore, in the present embodiment, two types of control for the transfer motor 20 are selectively used depending on the position of the sleeve 29 during range switching. Specifically, the transfer ECU 12 has a position where the chamfer 59 of the external teeth 29a of the sleeve 29 overlaps at least partially in the axial direction with the chamfer of the gear piece to be engaged with the sleeve 29 of the high gear piece 27 and the low gear piece 28. In this case, current control for controlling the drive current of the transfer motor 20 is performed. In other words, when the apex 59a of the chamfer 59 of the sleeve 29 is located between the positions (3) and (2) (or between the positions (4) and (5)) in FIG. The transfer ECU 12 limits the drive current of the transfer motor 20.

  As described above, when the chamfer 57 of the high gear piece 27 or the chamfer 58 of the low gear piece 28 and the chamfer 59 of the external teeth 29a of the sleeve 29 may come into contact with each other, the sleeve 29 may be stopped. Therefore, damage to the fork 30 or the like can be suppressed by appropriately controlling the drive current of the transfer motor 20.

  Further, the sleeve 29 is located at a position where the gear piece to be engaged with the sleeve 29 and the external tooth 29a of the sleeve 29 do not overlap in the axial direction (for example, between the positions (3) and (4) in FIG. 3). In this case, or when the pushing is completed, in other words, when there is no possibility that the sleeve 29 stops at a position other than the target position, the position control is performed, so that the drive current of the transfer motor 20 is limited more than necessary. The range can be switched quickly without any change.

  Note that “current control for controlling the drive current of the transfer motor 20” means that, for example, the transfer ECU 12 generates a current value that can generate a load necessary to perform range switching and a load that is less than the strength of the fork 30. It means that an upper limit value of current is set between possible current values and a current equal to or lower than the upper limit value is supplied to the transfer motor 20.

  Next, the procedure of the range switching control of the present embodiment that is executed by the transfer ECU 12 will be described with reference to the flowchart of FIG. In addition, although the case where it switches from a high speed range to a low speed range is demonstrated in the flowchart of FIG. 4, switching from a low speed range to a high speed range can also be performed with the same view.

  First, in step S1, the transfer ECU 12 determines whether or not the driver has operated the dial 48 from the high speed range (Hi) to the low speed range (Lo). If the determination in step S1 is NO, it is not a scene to which the present invention is applied, so END is performed as it is. On the other hand, if the determination in step S1 is YES, the process proceeds to step S2, and the transfer ECU 12 blinks the indicator indicating the low speed range provided in the vehicle 1 and then proceeds to step S3.

  In the next step S3, the transfer ECU 12 determines whether or not a range switching condition is satisfied. Here, the range switching condition is that the vehicle speed is 0, the automatic transmission 3 is in the neutral range, and the like. This is because when the input shaft 13 is rotating, it is difficult to engage the low gear piece 28 and the external teeth 29 a of the sleeve 29. If the determination in step S3 is NO, the determination in step S3 is repeated until the range switching condition is satisfied. On the other hand, if the determination in step S3 is yes, the process proceeds to step S4.

  In the next step S <b> 4, the transfer ECU 12 performs position control of the transfer motor 20. Specifically, the transfer ECU 12 sets the drive current of the transfer motor 20 to, for example, the maximum current so that the position of the sleeve 29 matches the target position, and reversely drives the transfer motor 20.

  In the next step S5, the transfer ECU 12 determines whether or not the apex 59a of the chamfer 59 of the sleeve 29 has reached the apex 58a position (position (4) in FIG. 3) of the chamfer 58 of the low gear piece 28. When the determination in step S5 is NO, the position control of the transfer motor 20 is continued. On the other hand, if the determination in step S5 is yes, the process proceeds to step S6.

  In next step S <b> 6, the transfer ECU 12 performs current control of the transfer motor 20. Specifically, the transfer ECU 12 changes the drive current of the transfer motor 20 to, for example, a fork protection control current value, and reversely drives the transfer motor 20. Here, the fork protection control current value is a current value set between a current value capable of generating a load necessary for performing range switching and a current value capable of generating a load less than the strength of the fork 30. It is. In this way, damage to the fork 30 and the like is suppressed by appropriately controlling the drive current of the transfer motor 20 from the position where the chamfer 59 of the sleeve 29 and the chamfer 58 of the low gear piece 28 may occur. can do. If the chamfer 59 of the sleeve 29 and the chamfer 58 of the low gear piece 28 come into contact with each other during the current control, the drive current of the transfer motor 20 is temporarily reduced (with the load removed), and the external teeth of the sleeve 29 are removed. Pushing can be performed by shifting the phase of 29a and the low gear piece 28.

  In the next step S7, the transfer ECU 12 determines whether the shoulder 59b of the chamfer 59 of the sleeve 29 has reached the position of the shoulder 58b of the chamfer 58 of the low gear piece 28, in other words, the external teeth 29a of the sleeve 29 and the low gear piece 28. It is determined whether or not the push separation is completed. If the determination in step S7 is NO, the sleeve 29 may stop due to contact between the chamfer 59 of the external teeth 29a of the sleeve 29 and the chamfer 58 of the low gear piece 28. Control continues. On the other hand, if the determination in step S7 is YES, in other words, if the push-out between the outer teeth 29a of the sleeve 29 and the low gear piece 28 is completed, the process proceeds to step S8.

  In next step S <b> 8, the transfer ECU 12 performs position control of the transfer motor 20. Specifically, the transfer ECU 12 changes the drive current of the transfer motor 20 to the maximum current again so that the position of the sleeve 29 coincides with the meshing completion position which is the target position, and reversely drives the transfer motor 20. .

  In the next step S <b> 9, the transfer ECU 12 determines whether or not the meshing between the external teeth 29 a of the sleeve 29 and the low gear piece 28 has been completed. Specifically, the transfer ECU 12 determines whether or not the vertex 58a of the chamfer 58 of the sleeve 29 has reached the position (6) in FIG. If the determination in step S9 is NO, the position control of the transfer motor 20 is continued. On the other hand, when the determination in step S9 is YES, the process proceeds to step S10, and the transfer ECU 12 ends the energization of the transfer motor 20.

  In the next step S11, the transfer ECU 12 turns on the blinking indicator so that the driver can recognize that the low speed range has been established, and then performs END.

  Next, the range switching control by the transfer ECU 12 will be described using the timing chart shown in FIG. In the timing chart of FIG. 5, the case of switching from the high speed range to the low speed range is described, but switching from the low speed range to the high speed range can be performed in a similar time series.

First, at t ₀ , since the sleeve 29 is in the meshing position with the high gear piece 27, the external teeth 29 a of the sleeve 29 are in a position that does not overlap with the low gear piece 28 to mesh with the sleeve 29 in the axial direction. The transfer ECU 12 executes position control of the transfer motor 20. As a result, the current value supplied to the transfer motor 20 becomes the maximum current value, so that the sleeve 29 quickly slides toward the low gear piece 28 as shown by the inclination of the stroke of the sleeve 29 in FIG.

Then, at t _1, the apex 59a of the chamfer 59 of the sleeve 29 reaches the apex contact position of the vertex 58a of the chamfer 58 of Rogiyapisu 28 (in FIG. 3 (4) position), the transfer ECU12 is transfer motor 20 control type is changed from position control to current control. As a result, the current value supplied to the transfer motor 20 becomes the fork protection control current value, so that even if the chamfer 59 of the sleeve 29 and the chamfer 58 of the low gear piece 28 come into contact with each other, the fork 30 and the like are damaged. Can be suppressed.

Next, at t _2, the shoulder 59b of chamfer 59 of the sleeve 29 reaches the shoulder between the contact position of the shoulder 58b of chamfer 58 of Rogiyapisu 28, in other words, vertex 59a is 3 of the chamfer 59 of the sleeve 29 When the middle (5) position is reached, the transfer ECU 12 returns the control mode of the transfer motor 20 from current control to position control. As a result, the current value supplied to the transfer motor 20 returns to the maximum current value, and the sleeve 29 quickly slides to the target position.

Next, at t ₃ , when the sleeve 29 reaches the engagement completion position with the low gear piece 28, the transfer ECU 12 turns off the range (Hi-Lo) switching control, and the current value supplied to the transfer motor 20 is 0. Become.

(Other embodiments)
The present invention is not limited to the embodiments, and can be implemented in various other forms without departing from the spirit or main features thereof.

  In the above embodiment, the present invention is applied to the vehicle 1 including the automatic transmission 3 as a transmission. However, the present invention is not limited thereto, and the present invention may be applied to a vehicle including a manual transmission. In this case, in addition to the vehicle speed being 0, the range switching condition may be that the clutch is depressed.

  In the above embodiment, the ECU for controlling the engine 2 and the automatic transmission 3 and the transfer ECU 12 are separated. However, the present invention is not limited to this, and the transfer ECU 12 may be a part of another ECU.

  Furthermore, in the above-described embodiment, the thrust of the piston 41 is directly generated by the rotational driving force of the transfer motor 20, but the present invention is not limited to this. For example, an electromagnetic clutch piston or a hydraulic piston controlled by the transfer motor 20 is used. , The thrust may be generated indirectly by the transfer motor 20.

  As described above, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  According to the present invention, when the high gear piece or the low gear piece and the teeth of the sleeve are meshed with each other, damage to the fork or the like can be suppressed, so that the clutch is pressed in the torque distribution control and the fork is moved in the range switching control. Is very useful when applied to a transfer device that uses a common motor.

4 Transfer device 7L, 7R Rear wheel (main drive wheel)
11L, 11R Front wheel (sub drive wheel)
12 Transfer ECU (control device)
18 Control clutch 20 Transfer motor 27 High gear piece 28 Low gear piece 29 Sleeve 30 Fork 57 Chamfa 58 Chamfa 59 Chamfa

Claims (1)

A high gear piece arranged in the axial direction with the teeth of the sleeve sliding in the axial direction by pressing the clutch in torque distribution control for distributing torque between the main drive wheel and the sub drive wheel using the clutch and the movement of the fork A transfer device in which movement of the fork in range switching control to establish a high speed range or a low speed range by meshing with a low gear piece is performed using a common motor,
A control device for performing position control for driving the motor so that the position of the sleeve matches the target position at the time of the range switching control;
When the chamfer of the tooth of the sleeve is at a position at least partially overlapping with the chamfer of the gear piece to be engaged with the sleeve of the high gear piece and the low gear piece, the control device of the motor A transfer device configured to perform current control for controlling drive current.

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