Clutch control

Abstract

Clutch control which has the following: - a claw clutch (CL4) comprising a first rotor (46) with engagement teeth (60) and a second rotor (44) arranged coaxially with the first rotor (46) with engagement teeth (70), wherein the claw clutch (CL4) is designed to be switched between an engaged state in which the engagement teeth (60, 70) are in engagement with one another, and a disengaged state in which the engagement between the engagement teeth (60, 70) is released, wherein the engagement teeth of the first rotor (46) have a first beveled portion (61) provided at a tip and a first engagement portion (62) extending away from the first beveled portion (61), and wherein the engagement teeth of the second rotor (44) have a second beveled portion (71) provided at a tip and a second beveled portion (71) extending away from the second beveled portion extending second engagement region (72); - an actuator (48) for moving one of the first rotor (46) and the second rotor (44) in an axial direction to switch the dog clutch (CL4) between the engaged state and the disengaged state; - a synchronization control unit for controlling an electric motor coupled to the second rotor (44) to control the rotational speed (N2) of the second rotor (44) such that the rotational speed (N2) of the second rotor (44) is approximated to the rotational speed (N1) of the first rotor (46) when the dog clutch (CL4) is switched to the engaged state; - an engagement control unit for controlling the actuating device (48) to move one of the first rotor (46) and the second rotor (44) toward the other rotor when the dog clutch (CL4) is switched to the engaged state, wherein the engagement control unit moves one of the first rotor (46) and the second rotor (44) to a position in which the first chamfered portion (61) and the second chamfered portion (71) of the engagement teeth (60, 70) are engaged with each other in the axial direction before a difference in the rotational speeds (N1, N2) between the first rotor (46) and the second rotor (44) is in a predetermined range (α) and the rotational speed (N2) of the second rotor (44) reaches the rotational speed (N1) of the first rotor (46); and - a synchronization prediction unit for predicting a synchronization time period (T1) required for the difference in rotational speeds (N1, N2) between the first rotor (46) and the second rotor (44) to be within the predetermined range (α), wherein the engagement control unit starts the movement of one of the first rotor (46) and the second rotor (44) on the basis of the synchronization time period (T1) before the difference in rotational speeds (N1, N2) between the first rotor (46) and the second rotor (44) is within the predetermined range (α).

Description

BACKGROUND 1. Technical field

[0001] The present invention relates to clutch controls, particularly clutch controls capable of switching a dog clutch to an engaged state. 2. Relevant state of the art

[0002] JP 2009-191954 A discloses a control device for a vehicle, including, among other things, a first engagement body, a second engagement body, an electric motor that rotates the first engagement body, an actuator, and a prediction device. The prediction device calculates a predicted value of the angular deviation between the first engagement body and the second engagement body after a delay time from a command signal until the start of the actuator, and from the speed deviation between the first engagement body and the second engagement body. An engagement command device outputs an engagement command to the actuator based on the predicted value of the angular deviation calculated by the prediction device.

[0003] A dog clutch for shifting a gear or driving mode is often incorporated into a powertrain of a hybrid vehicle or the like (see Japanese Unexamined Patent Application Publication JP 2006-038136 A). From the standpoint of suppressing power loss at the time of clutch disengagement, it is preferable to use a dog clutch that does not include a synchronization mechanism.

[0004] However, if the dog clutch does not have a synchronization mechanism, it is necessary to synchronize the rotational speeds at the front and rear, or in front of and behind the dog clutch, with high precision to smoothly shift the dog clutch into an engaged state. To overcome this, the drivetrain described in JP 2006-038136 A synchronizes the rotational speeds at the front and rear of the clutch using an electric motor.

[0005] However, even if the speeds are synchronized using an electric motor, it is extremely difficult to completely align the speeds at the front and rear of the clutch, and thus a state in which one speed exceeds the other speed and a state in which the other speed exceeds one speed alternately occur.

[0006] Specifically, since the relative rotation direction at the front and rear of the dog clutch is constantly changing, when switching a dog clutch to the engaged state, a situation arises in which a longitudinal spline is reciprocated and repeatedly moves inward and outward. The repeated inward and outward movement of the longitudinal spline results in an increase in the time required to switch a dog clutch and an increase in the size of an actuator that controls such a dog clutch. Therefore, it is desirable to switch a dog clutch to the engaged state smoothly. BRIEF DESCRIPTION OF THE INVENTION

[0007] An object of the present invention is to smoothly switch a dog clutch into the engaged state.

[0008] The object is achieved by a clutch control having the features of claim 1. Advantageous developments of the clutch control according to the invention are specified in the dependent claims 2 to 5. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The drawings show: Fig. 1 is a schematic view illustrating a powertrain mounted in a hybrid vehicle and a portion of the control system thereof; Fig. 2 is an exploded perspective view illustrating the structure of a clutch; Fig. 3A to 3D views for explaining an engagement process of longitudinal splines; Fig. 4A to 4D are views illustrating contact patterns of beveled areas; Fig. 5 is a diagram illustrating the number of revolutions N1, the number of revolutions N2 and a sleeve stroke movement when the clutch is engaged; Fig. 6 is a diagram illustrating, in a comparative example, the number of revolutions N1, the number of revolutions N2 and the sleeve stroke movement when the clutch is engaged; and Fig. 7 is a diagram illustrating the number of revolutions N1, the number of revolutions N2 and the sleeve stroke movement when the clutch is engaged. DETAILED DESCRIPTION

[0010] In the following, an example of the present invention will be described in detail with reference to the drawings. Fig. Figure 1 shows a schematic diagram illustrating a drivetrain 10 installed in a hybrid vehicle and a portion of its control system. A clutch control 11 is integrated into the drivetrain 10 as an example of the present invention.

[0011] As in Fig. As shown in Figure 1, the drive train 10 is provided with an internal combustion engine 12, a first motor generator M1, and a second motor generator M2 as drive sources. Furthermore, the drive train 10 is provided with a clutch CL1, a clutch CL2, a clutch CL3, and a clutch CL4 as dog clutches. Each of the clutches CL1 to CL4 is a dog clutch, meaning a dog clutch that does not have a rotation synchronization mechanism such as a synchronizing ring or the like.

[0012] A power split mechanism 13 for splitting the engine power for driving the wheels and the motor generator M2 is provided between the internal combustion engine 12 and the motor generator M2. The power split mechanism 13 has a carrier 14 coupled to the internal combustion engine 12 and a pinion 15 rotatably supported by the carrier 14.

[0013] The pinion 15 has two toothed portions 15a and 15b. A sun gear 16 and a ring gear 17 mesh with the toothed portion 15a, and a sun gear 18 meshes with the toothed portion 15b. The motor generator M2 is coupled to the sun gear 16, and a clutch hub 19 is fixed to the sun gear 18.

[0014] A clutch sleeve 20 is provided on the outer peripheral portion of the clutch hub 19, movable in the axial direction. A fork member 21 is attached to the clutch sleeve 20, and an actuator 22 is coupled to the fork member 21. By controlling the actuator 22 to move the clutch sleeve 20 in the direction of arrow a, the clutch sleeve 20 is engaged with a clutch gear 23.

[0015] Thus, the clutch hub 19, the clutch sleeve 20, and the clutch gear 23 form the clutch CL1. By engaging the clutch CL1, the sun gear 18 and the ring gear 17 can be engaged, and it becomes possible to stop the differential rotation of the power split mechanism 13. This means that by engaging the clutch CL1, the internal combustion engine 12 and the motor generator M2 can be directly coupled to each other via the power split mechanism 13.

[0016] Furthermore, by controlling the actuator 22 to move the clutch sleeve 20 in the direction of arrow b, the clutch sleeve 20 is engaged with a clutch gear 24. Thus, the clutch hub 19, the clutch sleeve 20, and the clutch gear 24 form the clutch CL2. By engaging the clutch CL2, it is possible to fix the sun gear 18 to a housing 25 and stop the sun gear 18, so that the rotational fluctuation of the ring gear 17 can be increased while reducing the rotational fluctuation of the motor generator M2.

[0017] This means that by engaging the clutch CL2 acting as a brake, it is possible to increase the speed of the ring gear 17 and a drive wheel output shaft 26 described later, while suppressing the speed of the motor generator M2, and thus it becomes possible to switch the power split mechanism 13 into an "overdrive" or overdrive state.

[0018] Furthermore, a drive gear 28 is fixed on a hollow shaft 27, which couples the ring gear 17 and the clutch gear 23 to each other, and a driven gear 29 meshing with the drive gear 28 is rotatably supported by the drive gear output shaft 26. A clutch gear 30 is fixed to the driven gear 29, and a clutch hub 31 adjacent to the clutch gear 30 is fixed to the drive gear output shaft 26. A clutch sleeve 32 is provided on the outer peripheral portion of the clutch hub 31, movable in the axial direction.

[0019] A fork member 33 is attached to the clutch sleeve 32, and an actuator 34 is coupled to the fork member 33. By controlling the actuator 34 to move the clutch sleeve 32 in the direction of arrow a, the clutch sleeve 32 is engaged with the clutch gear 30. Thus, the clutch hub 31, the clutch gear 30, and the clutch sleeve 33 form the clutch CL3.

[0020] By engaging clutch CL3, it becomes possible to couple the ring gear 17 and the drive wheel output shaft 26. This means that by engaging clutch CL3, it becomes possible to connect the internal combustion engine 12 and the motor generator M2 to the drive wheel output shaft 26. On the other hand, by disengaging clutch CL3, it becomes possible to disconnect the internal combustion engine 12 and the motor generator M2 from the drive wheel output shaft 26.

[0021] A driven gear 40 is fixed to the other end portion of the drive gear output shaft 26, and a drive gear 41 meshing with the driven gear 40 is fixed on a transmission shaft 42. A clutch hub 43 is fixed on the transmission shaft 42, and a clutch gear 44 adjacent to the clutch hub 43 is fixed on an engine output shaft 45 of the motor generator M1.

[0022] Furthermore, a clutch sleeve 46 is provided on the outer peripheral portion of the clutch hub 43, movable in the axial direction. A fork element 47 is attached to the clutch sleeve 46, and an actuating device 48 is coupled to the fork element 47. By controlling the actuating device 48 to move the clutch sleeve 46 in the direction of arrow a, the clutch sleeve 46 is engaged with the clutch gear 44.

[0023] Thus, the clutch hub 43, the clutch gear 44, and the clutch sleeve 46 form the clutch CL4. Engaging the clutch CL4 makes it possible to connect the motor generator M1 to the drive wheel output shaft 26. On the other hand, disengaging the clutch CL4 makes it possible to disconnect the motor generator M1 from the drive wheel output shaft 26.

[0024] To perform shift control of the clutches CL1 to CL4 of the powertrain 10, a drive circuit 50 is connected to the actuators 22, 34, and 48, and an auxiliary device battery (not shown) is connected to the drive circuit 50 via a power line. An inverter 52 is connected to a stator 51 of the motor generator M1, and a high-voltage battery (not shown) is connected to the inverter 52 via a power line.

[0025] The clutch control 11 has a control unit 53 that outputs control signals to the inverter 52 and the drive circuit 50. Connected to the control unit 53 are a rotation sensor 54 for detecting the number of revolutions (speed) N1 of the transmission shaft 52, i.e., the clutch sleeve 46, and a rotation sensor 55 for detecting the number of revolutions (speed) N2 of the motor output shaft 45, i.e., the clutch gear 44.

[0026] When the shift control of the clutch CL4 is executed, the control unit 53 outputs the control signal based on the number of revolutions N1 and N2 at the front and rear of the clutch to the inverter 52 to control the number of revolutions of the motor generator M1, and further outputs the control signal to the drive circuit 50 to control the operating state of the actuator. The control unit 53 has a CPU, a ROM, and a RAM.

[0027] The following describes a control operation when clutch CL4 is switched from the disengaged state to the engaged state. In the following description, clutch CL4 is used as an example among the clutches CL1 to CL4 provided in the powertrain 10, but the other clutches CL1 to CL3 can also be switched from the disengaged state to the engaged state using the control operation described below.

[0028] Fig. Figure 2 shows an exploded perspective view showing the construction of the CL4 coupling. As shown in Fig. 2, the clutch CL4 has the clutch sleeve (first rotor) 46 which is provided on the outer peripheral portion of the clutch hub 43 so as to be movable in the axial direction, and the clutch gear (second rotor) 44 which is arranged coaxially with the clutch sleeve 46.

[0029] On the inner peripheral surface of the clutch sleeve 46, a plurality of longitudinal spline teeth 60 are formed, projecting inward in the radial direction. The longitudinal spline teeth 60 extend in the axial direction and are arranged at predetermined intervals in the circumferential direction. Furthermore, each of the longitudinal spline teeth (engaging teeth) 60 has a tapered portion (first tapered portion) 61 provided at its tip and an inversely tapered portion (first engaging portion) 62 extending from the tapered portion 61.

[0030] The chamfered portion 61 has a chamfered surface 61a provided on one side in the rotation direction and a chamfered surface 61b provided on the other side in the rotation direction. Similarly, a plurality of longitudinal spline teeth 70 are formed on the outer peripheral surface of the clutch gear 44, projecting outward in the radial direction. The longitudinal spline teeth 70 extend in the axial direction and are arranged at predetermined intervals in the circumferential direction.

[0031] Further, each of the longitudinal spline teeth (engaging teeth) 70 has a tapered portion (second tapered portion) 71 provided at its tip, and an inversely tapered portion (second engaging portion) 72 extending from the tapered portion 71. The tapered portion 71 has a tapered surface 71a provided on one side in the rotation direction and a tapered surface 71b provided on the other side in the rotation direction.

[0032] Next, an engagement process of the longitudinal spline 60 of the clutch sleeve 46 and the longitudinal spline 70 of the clutch gear 44 is described. Fig. 3A to 3D show views for explaining the engagement process of the longitudinal splines 60 and 70.

[0033] As in Fig. 3A, in a position in which the stroke movement of the clutch sleeve 46 moved by the actuating device 48 (hereinafter referred to as sleeve stroke movement) reaches the value zero, ie in a neutral position of the clutch sleeve 46, the longitudinal spline toothing 60 of the clutch sleeve 46 is separated from the longitudinal spline toothing 70 of the clutch wheel 44 in the axial direction.

[0034] This means that the engagement between the longitudinal spline 60 and the longitudinal spline 70 is cancelled. When the sleeve stroke movement subsequently reaches the position S1 by controlling the actuating device 48 to move the coupling sleeve 46 in the direction of arrow a, the coupling sleeve 46 moves into a contact position with the beveled area, as shown in Fig. 3B is shown.

[0035] When the sleeve stroke movement reaches the position S2, the coupling sleeve 46 further moves into a contact position with the inversely tapered portion, as shown in Fig. 3C. Furthermore, when the sleeve stroke movement reaches position S3, the coupling sleeve 46 moves into a Fig. 3D representation of the investment position.

[0036] As in Fig. 3B, the contact position with the chamfered portion is a position where the tips of the chamfered portions 61 and 71 overlap each other in the axial direction. By moving the coupling sleeve 46 beyond the contact position with the chamfered portion, it is possible to bring the chamfered portions 61 and 71 into contact with each other, and it becomes possible to mechanically synchronize the phases of the splines 60 and 70.

[0037] As further stated in Fig. 3C is shown with a broken line, the contact position with the inverse tapered portion is a position where the interface area between the tapered portion 61 and the inverse tapered portion 62 and the interface area between the tapered portion 71 and the inverse tapered portion 72 overlap each other in the axial direction.

[0038] By moving the clutch sleeve 46 beyond the contact position with the inversely tapered portion, it is possible to engage the inversely tapered portions 62 and 72, and the clutch CL4 is thereby switched to the engaged state. Furthermore, the contact position is a position in which the movement of the clutch sleeve 46 is prevented by a stop (not shown).

[0039] In the following, an effect of a clutch engagement process is described based on the contact pattern of the beveled areas 61 and 71. The Fig. 4A to 4D show views for explaining the contact patterns of the beveled portions 61 and 71. In the Fig. 4A to 4D, the relative rotation directions of the clutch sleeve 46 and the clutch wheel 44 are shown by outlined and open arrows, respectively.

[0040] It should be noted that with regard to the open arrows of the Fig. 4A to 4D, the upward-pointing open arrows each indicate an acceleration direction, while the downward-pointing arrows each indicate a deceleration direction. Furthermore, the arrows a each indicate the direction of movement of the clutch sleeve 46 when the clutch CL4 is switched to the engaged state.

[0041] First, a case is described in which the rotational speed of the clutch wheel 44 is lower than that of the clutch sleeve 46, as shown in the Fig. 4A and Fig. 4B. As shown in Fig. 4A, in a case where the tapered surface 61b of the clutch sleeve 46 and the tapered surface 71b of the clutch gear 44 are brought into contact with each other as shown by an arrow b, the tapered surface 61b performs a sliding movement on the tapered surface 71b, so that the clutch sleeve 46 moves smoothly toward the clutch gear 44.

[0042] On the other hand, as in Fig. 4B, in a case where the tapered surface 61a of the clutch sleeve 46 and the tapered surface 71b of the clutch gear 44 are brought into contact with each other as shown by an arrow b, the tapered surface 71b is pressed inwardly by the tapered surface 61a, so that the clutch sleeve 46 moves toward the clutch gear 44 while being dragged.

[0043] That is, in the case where the rotational speed of the clutch wheel 44 is lower than the rotational speed of the clutch sleeve 46, it is preferable to form the chamfered portions 61 and 71 in the manner shown in Fig. 4A to bring the patterns illustrated into contact with each other.

[0044] Furthermore, a case is described in which the rotational speed of the clutch wheel 44 is higher than the rotational speed of the clutch sleeve 46, as shown in the Fig. 4C and Fig. 4D. As shown in Fig. 4C, in the case where the tapered surface 61a of the clutch sleeve 46 and the tapered surface 71b of the clutch gear 44 are brought into contact with each other as shown by an arrow b, the tapered surface 61a performs a sliding movement on the tapered surface 71b, so that the clutch sleeve 46 moves smoothly toward the clutch gear 44.

[0045] As in Fig. 4D, in a case where the tapered surface 61b of the clutch sleeve 46 and the tapered surface 71a of the clutch gear 44 are brought into contact with each other as shown by an arrow b, the tapered surface 71a is pressed inward by the tapered surface 61b, so that the clutch sleeve 46 moves toward the clutch gear 44 while being carried along.

[0046] That is, in the case where the rotational speed of the clutch gear 44 is higher than the rotational speed of the clutch sleeve 46, it is preferable to form the chamfered portions 61 and 71 according to the Fig. 4C into contact with each other.

[0047] The following describes a control operation when the CL4 clutch is engaged. Fig. Figure 5 shows a diagram explaining the number of revolutions N1, the number of revolutions N2 and the sleeve stroke when the clutch CL4 is engaged. Fig. 5, the number of revolutions N1 is shown with a broken line, the number of revolutions N2 is shown with a solid line, and the sleeve stroke movement is shown with a dash-dotted line.

[0048] As in Fig. 5, at the time of starting the control operation, when the clutch CL4 is in the disengaged state, the number of revolutions N2 is smaller than the number of revolutions N1, and thus the control unit 53 starts a rotation synchronization control that increases the number of revolutions N2 using the motor generator (electric motor) M1.

[0049] The control unit 53, which acts as a synchronization control unit, sets the number of revolutions N1 as the target number of revolutions or target speed and controls the motor generator M1 via the inverter 53 such that the number of revolutions N2 of the motor generator 1 reaches the number of revolutions N1. As shown in Fig. 5 by the letter X, the control unit 53 acting as a synchronization prediction unit then calculates a rising speed of the number of revolutions N2 (an angular acceleration of the clutch gear 44) and further calculates a synchronization period T1 of the number of revolutions N2 with respect to the number of revolutions N1.

[0050] The synchronization time T1 refers to a time required for a speed difference between the number of revolutions N1 and the number of revolutions M2 to be within a predetermined range α. The predetermined range α is a speed difference that is allowable when the clutch CL4 is engaged, and is a value predetermined based on the shape of each of the chamfered portions 61 and 71, the strength of the longitudinal spline, and the speed range.

[0051] In the Fig. In the case illustrated in Fig. 5, a time required for the number of revolutions N2 to reach the predetermined number of revolutions n in the predetermined range α is calculated as the synchronization time required for the difference in speeds between the number of revolutions N1 and the number of revolutions N2 to be in the predetermined range α.

[0052] Once the synchronization time T1 is calculated in this way, a predetermined stroke time T2 is subtracted from the synchronization time T1, and an actuation time t of the actuator 48 is specified. The stroke time T2 is a time required for the sleeve stroke to reach S2, that is, a time required for the coupling sleeve 46 to reach the contact position with the inversely tapered portion, which time is specified using a test or simulation. Subsequently, the control unit 53 acting as an engagement control unit outputs the control signal to the drive circuit 50 to cause the drive circuit 50 to start the operation of the actuator 48 at the actuation time t.

[0053] By starting the movement of the coupling sleeve 46 at the actuation time t, as shown in Fig. 5 by the letter Y, it thus becomes possible to move the clutch sleeve 46 into the contact position with the inversely tapered portion before the difference in rotational speeds between the clutch sleeve 46 and the clutch gear 44 is in the predetermined range α and the number of revolutions N2 of the clutch gear 44 reaches the number of revolutions N1 of the clutch sleeve 46.

[0054] This makes it possible to move the clutch sleeve 46 into the contact position with the inversely tapered portion before the number of revolutions N2 of the clutch gear 44 exceeds the number of revolutions N1 of the clutch sleeve 46, and thus the clutch CL4 can be smoothly switched to the engaged state. This means that by moving the clutch sleeve 46 into the contact position with the inversely tapered portion before the clutch gear 44 rotating synchronously therewith exceeds the clutch sleeve 46 in terms of speed, the contact pattern of the tapered portions 61 and 71 can be adapted to the contact pattern of the Fig. 4A or the contact pattern of the Fig. 4B limit.

[0055] Even if the first contact pattern of the beveled areas 61 and 71 is the contact pattern of the Fig. 4B, it is thus possible to convert the contact pattern of the same into the contact pattern of the Fig. 4A, and it becomes possible to smoothly switch the clutch CL4 to the engaged state.

[0056] Furthermore, as in Fig. 5, the movement of the clutch sleeve 46 is started before the difference in rotational speeds between the clutch sleeve 46 and the clutch gear 44 falls within the predetermined range α, it is further possible to reduce a switching time period when switching the clutch CL4 to the engaged state.

[0057] Furthermore, since the CL4 clutch can be smoothly switched to the engaged state, the axial force of the actuator 48 can be reduced, and it becomes possible to reduce the size of the actuator 48. Furthermore, since the CL4 clutch can be smoothly switched to the engaged state, a rotation synchronization mechanism such as the synchronizer ring can be omitted from the CL4 clutch, and the power loss in the disengaged state of the CL4 clutch can be significantly reduced.

[0058] Fig. Fig. 6 is a schematic diagram showing, as a comparative example, the number of revolutions N1, the number of revolutions N2 and the sleeve stroke when the clutch CL4 is engaged. As in the comparative example of Fig. 6, in a case where the movement of the clutch sleeve 46 is started after the number of revolutions N2 is synchronized with the number of revolutions N1, as illustrated by reference symbol Z1, there is a situation where the number of revolutions N2 falls below or rises above the number of revolutions N1 at the time the tapered portions 61 and 71 come into contact with each other.

[0059] This means that the contact pattern of the bevelled areas 61 and 71 can be any of the Fig. 4A to 4D, and thus there is a possibility that the contact pattern of the Fig. 4B and the contact pattern of the Fig. 4D are repeated alternately. As indicated by a reference symbol Z2 in Fig. 6, the coupling sleeve 46 thus repeatedly enters and leaves the area near the contact position with the tapered portion (the sleeve stroke S1) while being switched.

[0060] In contrast, according to the illustration in Fig. 5 by moving the coupling sleeve 46 into the contact position with the inversely tapered portion (the sleeve stroke S2) before the number of revolutions N2 of the coupling wheel 44 exceeds the number of revolutions N1 of the coupling sleeve 46, the contact pattern of the tapered portions 61 and 71 to that shown in Fig. 4A or Fig. 4B, so that it becomes possible to switch the clutch CL4 smoothly into the engaged state.

[0061] Although in the above description, the clutch CL4 is switched to the engaged state after the number of revolutions N2 is increased to approximate the number of revolutions N1, the present invention is not limited to this, and the clutch CL4 may also be switched to the engaged state after the number of revolutions N2 is reduced to approximate the number of revolutions N1. Fig. 7 is a schematic diagram for explaining the number of revolutions N1, the number of revolutions N2 and the sleeve stroke when the clutch CL4 is engaged.

[0062] As in Fig. 7, at the time of starting the control operation, when the clutch CL4 is in the disengaged state and the number of revolutions N2 is greater than the number of revolutions N1, the control unit 53 starts the rotation synchronization control which decreases the number of revolutions N2 by using the motor generator M1.

[0063] The control unit 53 sets the number of revolutions N1 as the target number of revolutions or target speed and controls the motor generator M1 via the inverter 52 so that the number of revolutions N2 of the motor generator M1 reaches the number of revolutions N1. As indicated by a letter X in Fig. 7, the control unit 53 then calculates a reduction speed of the number of revolutions N2 (the angular acceleration of the clutch gear 44) and calculates the synchronization time period T1 of the number of revolutions N2 with respect to the number of revolutions N1.

[0064] Once the synchronization time T1 is calculated in this way, the predetermined stroke movement time T2 is subtracted from the synchronization time T1, and the actuation time t of the actuating device 48 is specified. Subsequently, the control unit 53 outputs the control signal to the drive circuit 50, causing the drive circuit 50 to start the operation of the actuating device 48 at the actuation time t.

[0065] By starting the movement of the coupling sleeve 46 at the actuation time t, as indicated by a reference symbol Y in Fig. 7, the clutch sleeve 46 can thus be moved into the contact position with the inversely tapered portion before the difference in rotational speed between the clutch sleeve 46 and the clutch gear 44 is in the predetermined range and the number of revolutions N2 of the clutch gear 44 reaches the number of revolutions N1 of the clutch sleeve 46.

[0066] This makes it possible to move the clutch sleeve 46 into the contact position with the inversely tapered portion before the number of revolutions N2 of the clutch wheel 44 is reduced to be less than the number of revolutions N1 of the clutch sleeve 46, so that it becomes possible to smoothly switch the clutch CL4 into the engaged state. This means that by moving the clutch sleeve 46 into the contact position with the inversely tapered portion before the clutch sleeve 46 exceeds the synchronously rotating clutch wheel 44 in terms of speed, the contact pattern of the tapered portions 61 and 71 can be adapted to the contact pattern of the Fig. 4C or the Fig. 4D can be limited.

[0067] Even if the first contact pattern of the beveled areas 61 and 71 is the contact pattern of the Fig. 4D, it is therefore possible to match the contact pattern of the same at the next time to the contact pattern of the Fig. 4C and the CL4 clutch can be smoothly switched to the engaged state.

[0068] Although in the above description, the double-sided chamfered portions 61 and 71 each having two chamfered surfaces are provided as the chamfered portions 61 and 71 formed in the longitudinal spline, the present invention is not limited to this, and a single-sided chamfered portion having one chamfered surface may also be provided.

[0069] In the case where the tapered portion has only one tapered surface, it is determined whether or not the clutch CL4 can be smoothly engaged depending on the relative rotation direction of the clutch sleeve 46 and the clutch gear 44, and thus the shifting operation is carried out using the Fig. 5 or Fig. 7 illustrated control process.

[0070] The present invention is not limited to the above-described example and can be modified in various ways without departing from the scope thereof. Although the present invention is applied to the clutches CL1 to CL4 integrated into the powertrain 10 of the hybrid vehicle in the above description, the present invention is not limited thereto, and can also be applied to a dog clutch integrated into a drive device of a transmission or the like.

[0071] Although the splines 60 and 70 shown in the drawings include the inversely tapered portions 62 and 72, whose surfaces are inclined relative to the rotational direction and the axial direction, as the first and second engagement portions, the present invention is not limited thereto. For example, straight portions each having a surface orthogonal to the rotational direction (a surface parallel to the axial direction) may also be formed in the splines 60 and 70 as the first and second engagement portions.

[0072] Although electric actuators 22, 34, and 48 are used as the actuators 22, 34, and 48 for switching the clutches CL1 to CL4, the present invention is not limited to this, and hydraulic actuators may also be used. Although a single control unit 53 performs the functions of the synchronization control unit, the engagement control unit, and the synchronization prediction unit in the above description, the present invention is not limited to this. For example, the synchronization control unit, the engagement control unit, and the synchronization prediction unit may also be configured with a plurality of separate control units. List of reference symbols 10 Drivetrain 11 Clutch control 12 combustion engine 13 Power sharing mechanism 14 carriers 15 pinions 15a Gearing area 15b Gearing area 16 Sun gear 17 Ring gear 18 Sun gear 19 Clutch hub 20 coupling sleeve 21 Fork element 22 Actuating device 23 Clutch gear 24 Clutch gear 25 housings 26 Wheel output shaft 27 Hollow shaft 28 Drive gear 29 driven gear 30 clutch gear 31 Clutch hub 32 coupling sleeve 33 Fork element 34 Actuating device 40 driven gear 41 Drive gear 42 Transmission shaft 43 Clutch hub 44 Clutch gear (second rotor) 45 Engine output shaft 46 Coupling sleeve (first rotor) 47 Fork element 48 Actuating device 50 control circuit 51 Stator 52 inverters 53 Control unit 54 Rotation sensor 55 rotation sensor 60 engagement teeth 61 beveled area 61a bevelled surface 61b bevelled surface 62 Intervention area 70 engagement teeth 71 beveled area 71a bevelled surface 71b bevelled surface N1 Speed ​​of the first rotor 46 N2 Speed ​​of the second rotor 44

Claims

[1] Clutch control comprising: - a claw clutch (CL4) comprising a first rotor (46) with engagement teeth (60) and a second rotor (44) arranged coaxially with the first rotor (46) with engagement teeth (70), wherein the claw clutch (CL4) is designed to be switched between an engaged state in which the engagement teeth (60, 70) are in engagement with one another, and a disengaged state in which the engagement between the engagement teeth (60, 70) is released, wherein the engagement teeth of the first rotor (46) have a first beveled portion (61) provided at a tip and a first engagement portion (62) extending away from the first beveled portion (61), and wherein the engagement teeth of the second rotor (44) have a second beveled portion (71) provided at a tip and a second beveled portion (71) extending away from the second beveled portion extending second engagement region (72); - an actuator (48) for moving one of the first rotor (46) and the second rotor (44) in an axial direction to switch the dog clutch (CL4) between the engaged state and the disengaged state; - a synchronization control unit for controlling an electric motor coupled to the second rotor (44) to control the rotational speed (N2) of the second rotor (44) such that the rotational speed (N2) of the second rotor (44) is approximated to the rotational speed (N1) of the first rotor (46) when the dog clutch (CL4) is switched to the engaged state; - an engagement control unit for controlling the actuating device (48) to move one of the first rotor (46) and the second rotor (44) toward the other rotor when the dog clutch (CL4) is switched to the engaged state, wherein the engagement control unit moves one of the first rotor (46) and the second rotor (44) to a position in which the first chamfered portion (61) and the second chamfered portion (71) of the engagement teeth (60, 70) are engaged with each other in the axial direction before a difference in the rotational speeds (N1, N2) between the first rotor (46) and the second rotor (44) is in a predetermined range (α) and the rotational speed (N2) of the second rotor (44) reaches the rotational speed (N1) of the first rotor (46); and - a synchronization prediction unit for predicting a synchronization time period (T1) required for the difference in rotational speeds (N1, N2) between the first rotor (46) and the second rotor (44) to be within the predetermined range (α), wherein the engagement control unit starts the movement of one of the first rotor (46) and the second rotor (44) on the basis of the synchronization time period (T1) before the difference in rotational speeds (N1, N2) between the first rotor (46) and the second rotor (44) is within the predetermined range (α). [2] A clutch controller according to claim 1, wherein the engagement control unit moves one of the first rotor (46) and the second rotor (44) to a position in which the first engagement portion and the second engagement portion (62, 72) are engaged with each other in the axial direction before the difference in the rotational speeds (N1, N2) between the first rotor (46) and the second rotor (44) is in the predetermined range (α) and the rotational speed (N2) of the second rotor (44) reaches the rotational speed (N1) of the first rotor (46). [3] A clutch control according to claim 1 or 2, wherein the dog clutch (CL4) does not have a rotation synchronization mechanism. [4] Clutch control according to claim 1, wherein the first rotor (46) is a clutch sleeve and the second rotor (44) is a clutch wheel arranged coaxially to the clutch sleeve (46), wherein the first engagement region (62) is a first inversely tapered region (62) and the second engagement region (72) is a second inversely tapered region (72), wherein the first bevelled portion (61) has a bevelled surface (61a) arranged on one side in the direction of rotation and a bevelled surface (61b) arranged on the other side in the direction of rotation, wherein the second bevelled portion (71) has a bevelled surface (71a) arranged on one side in the direction of rotation and a bevelled surface (71b) arranged on the other side in the direction of rotation, wherein the engagement control unit moves the first rotor (46) beyond a contact position with the inversely tapered region before the difference in the rotational speeds (N1, N2) between the first rotor (46) and the second rotor (44) is in the predetermined range (α) and the rotational speed (N2) of the second rotor (44) reaches the rotational speed (N1) of the first rotor (46), and wherein the contact position with the inversely tapered portion is a position in which an interface region between the first tapered portion (61) and the first inversely tapered portion (62) and an interface region between the second tapered portion (71) and the second inversely tapered portion (72) overlap each other in the axial direction. [5] Clutch control according to claim 4, wherein the engagement control unit subtracts a predetermined stroke movement time period (T2) from the synchronization time period (T1), and an actuation time (t) of the actuating device (48) is specified, wherein the stroke movement time (T2) is a time required for the first rotor (46) to reach the contact position with the inversely tapered portion, and wherein the engagement control unit starts an operation of the actuating device (48) at the actuation time (t) to start the movement of the first rotor (46) at the actuation time (t).

Images