Vehicle drive device

Abstract

To control a state of an engagement mechanism by using a relatively inexpensive sensor.SOLUTION: A vehicle drive device includes: an engagement mechanism; a solenoid; a sensor; an output generating section for generating output signals of two values so that when a driven member is in a first end position, the output signal has a first value, and when the driven member is in a second end position, the output signal has a second value based on the electric signal from the sensor; and a control section. The output generating section generates an output signal so that a value of the output signal is switched from the first value to the second value in a first intermediate position when the driven member moves from the first end position to the second end position, and the value of the output signal is switched from the second value to the first value in a second intermediate position when the driven member moves from the second end position to the first end position. The first intermediate position is closer to the second end position than the second intermediate position.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a vehicle drive system. [Background technology]

[0002] In a differential drive device provided in a power transmission path from a power source to wheels, a technique is known in which a coupling (engagement mechanism) is provided to mechanically switch between a state in which power can be transmitted to the wheels and a state in which power cannot be transmitted to the wheels. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2013-512402 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned conventional technology, a transmitter element provided on a movable member of a joint and a sensor provided on a fixed side (housing) are made to cooperate with each other to continuously (linearly) monitor the distance between the transmitter element and the sensor. However, such a configuration has a problem in that the processing load for monitoring the state of the joint becomes excessive.

[0005] Therefore, in one aspect, an object of the present disclosure is to control the state of an engagement mechanism using a relatively inexpensive sensor. [Means for solving the problem]

[0006] According to one aspect, the present invention provides a power transmission system including an engagement mechanism that is provided between an input member and an output member in a power transmission path from a power source to a wheel, and that selectively forms an engaged state in which power transmission is possible between the input member and the output member and a non-engaged state in which power transmission is not possible between the input member and the output member; a solenoid having a movable element mechanically connected to the engagement mechanism, the solenoid moving a driven member of the engagement mechanism via the movable element between a first end position on a side where the engagement mechanism is brought into an engaged state and a second end position on a side where the engagement mechanism is brought into a disengaged state; a sensor that generates an electric signal according to the amount of movement of the movable element or the driven member; an output generating unit that generates a binary output signal based on the electrical signal from the sensor, the binary output signal having a first value when the driven member is at the first end position and a second value when the driven member is at the second end position; A control unit that controls energization of the solenoid based on the output signal from the output generating unit, the output generating unit generates the output signal such that, when the driven member moves from the first end position to the second end position, a value of the output signal switches from the first value to the second value at a first intermediate position between the first end position and the second end position, and, when the driven member moves from the second end position to the first end position, a value of the output signal switches from the second value to the first value at a second intermediate position between the first end position and the second end position; A vehicle drive arrangement is provided, wherein the first intermediate position is closer to the second end position than the second intermediate position. Effect of the Invention

[0007] In one aspect, the present disclosure allows for the use of relatively inexpensive sensors to control the state of the engagement mechanism. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a skeleton diagram of a vehicle drive system. [Diagram 2] FIG. 2 is a schematic diagram showing the configuration of a differential gear mechanism and an engagement mechanism. [Diagram 3] FIG. 2 is an explanatory diagram of a first element and a second element. [Figure 4] 2 is a schematic block diagram illustrating functions of a control device for a vehicle drive device. FIG. [Diagram 5] 4 is an explanatory diagram of the characteristics of an on / off signal generated based on an output from a position sensor. FIG. [Figure 6] FIG. 4 is an explanatory diagram of output characteristics of a position sensor. [Figure 7] 11 is a table showing the relationship between the output of the position sensor and the state of the engagement mechanism for each transition mode. FIG. [Figure 8] FIG. 11 is an explanatory diagram of retry control for avoiding lockup. [Figure 9] 5 is a schematic flowchart showing an example of a process executed by the control device in a transition mode from a non-engaged state to an engaged state. [Figure 10] 5 is a schematic flowchart showing an example of a process executed by the control device in a transition mode from an engaged state to a disengaged state. [Figure 11] 13A and 13B are schematic diagrams showing other examples of the arrangement of the engagement mechanism. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Each embodiment will be described in detail below with reference to the accompanying drawings. Note that the dimensional ratios in the drawings are merely examples and are not limiting, and shapes and the like in the drawings may be partially exaggerated for the sake of explanation. In addition, in the drawings, for ease of viewing, reference symbols may be given to only some of the parts that exist in a plurality of parts with the same attribute.

[0010] In the following, first, a vehicle drive system 100 to which the vehicle drive device 17 according to the present embodiment can be suitably applied will be described, and then the vehicle drive device 17 according to the present embodiment will be described.

[0011] [Entire drive system] Fig. 1 is a skeleton diagram of a vehicle drive system 100 including a rotating electric machine 1 and a power transmission mechanism 7. In Fig. 1, an X direction and an X1 side and an X2 side along the X direction are defined. The X direction is parallel to the direction of a first axis A1 (hereinafter also referred to as the "axial direction").

[0012] The vehicle drive system 100 is mounted on a vehicle. The type of vehicle is arbitrary, and the vehicle may be a four-wheeled vehicle or a vehicle other than a four-wheeled vehicle.

[0013] In the example shown in FIG. 1, the vehicle drive system 100 includes a vehicle drive device 17 and left and right output members 18A, 18B.

[0014] The vehicle drive device 17 includes a rotating electric machine 1 and a power transmission mechanism 7. In FIG.

[0015] The rotating electric machine 1 functions as a drive source for wheels W of a vehicle. The rotating electric machine 1 may also function as a generator.

[0016] The power transmission mechanism 7 is provided on a power transmission path that connects the rotating electric machine 1 and wheels W, and transmits power (rotational torque) from the rotating electric machine 1 to the wheels W.

[0017] The power transmission mechanism 7 includes an input member 3 , a counter gear mechanism 4 , and a differential gear mechanism 5 .

[0018] The input member 3 has an input shaft 31 and an input gear 32. The input shaft 31 is a rotating member that rotates around the first axis A1. The input gear 32 is a gear that transmits rotational torque (driving force) from the rotating electric machine 1 to the counter gear mechanism 4. The input gear 32 is provided on the input shaft 31 of the input member 3 so as to rotate integrally with the input shaft 31 of the input member 3.

[0019] The counter gear mechanism 4 is disposed in the power transmission path between the input member 3 and the differential gear mechanism 5. The counter gear mechanism 4 has a counter shaft 41, a first counter gear 42, and a second counter gear 43.

[0020] The counter shaft 41 is a rotating member that rotates around the second shaft A2. The second shaft A2 extends parallel to the first shaft A1. The first counter gear 42 is an input element of the counter gear mechanism 4. The first counter gear 42 meshes with the input gear 32 of the input member 3. The first counter gear 42 is connected to the counter shaft 41 so as to rotate integrally therewith.

[0021] The second counter gear 43 is an output element of the counter gear mechanism 4. In the present embodiment, for example, the second counter gear 43 is formed to have a smaller diameter than the first counter gear 42. The second counter gear 43 is provided on the counter shaft 41 so as to rotate integrally with the counter shaft 41.

[0022] The differential gear mechanism 5 is disposed on a third axis A3 serving as the rotation axis thereof. The third axis A3 extends parallel to the first axis A1. The differential gear mechanism 5 distributes the driving force transmitted from the rotating electric machine 1 to left and right output members 18A and 18B. The configuration of the differential gear mechanism 5 will be described later.

[0023] The left and right output members 18A, 18B are drivingly connected to the left and right wheels W, respectively. The left and right output members 18A, 18B transmit the driving force distributed by the differential gear mechanism 5 to the wheels W. Note that the left and right output members 18A, 18B may be constituted by two or more members.

[0024] In this way, the rotating electric machine 1 drives the wheels W via the power transmission mechanism 7. However, in other embodiments, other speed reduction mechanisms such as a planetary gear mechanism may be used.

[0025] [Differential gear mechanism and engagement mechanism] Fig. 2 is a schematic diagram showing the configuration of the differential gear mechanism 5 and the engagement mechanism 58. In addition to the differential gear mechanism 5 and the engagement mechanism 58, Fig. 2 also shows a solenoid 59 and the like. In Fig. 2, a member marked with the symbol BR typically represents a bearing (the same applies to Fig. 11 described later).

[0026] The differential gear mechanism 5 includes a differential input gear 51, which meshes with the second counter gear 43 (see FIG. 1) of the counter gear mechanism 4. The differential gear mechanism 5 also includes a differential case 52, in which a differential mechanism carrier 53 is supported rotatably about a third axis A3. The differential mechanism carrier 53 houses a pinion shaft 54, a pinion gear 55, left and right side gears 56, etc. The left and right side gears 56 are connected to the left and right output members 18A, 18B (see FIG. 1) so as to rotate integrally with them, respectively.

[0027] In this embodiment, the vehicle drive device 17 (see FIG. 1 ) further includes an engagement mechanism 58. The engagement mechanism 58 is provided between the differential case 52 and the differential mechanism carrier 53. When the engagement mechanism 58 is in an engaged state, power transmission between the differential case 52 and the differential mechanism carrier 53 is possible, and when the engagement mechanism 58 is in a disengaged state, power transmission between the differential case 52 and the differential mechanism carrier 53 is disabled.

[0028] Specifically, when the engagement mechanism 58 is in an engaged state, the differential case 52 and the differential mechanism carrier 53 are integrated. In this case, when the differential case 52 and the differential mechanism carrier 53 rotate about the third axis A3, a normal differential gear mechanism function is realized, and power is transmitted to the left and right output members 18A, 18B (see FIG. 1). On the other hand, when the engagement mechanism 58 is in a disengaged state, the differential case 52 and the differential mechanism carrier 53 are mechanically separated. In this case, even if the differential case 52 rotates about the third axis A3, the differential mechanism carrier 53 does not rotate as a result, and even if the differential mechanism carrier 53 rotates about the third axis A3, the differential case 52 does not rotate as a result.

[0029] In this embodiment, the engagement mechanism 58 is in the form of a dog clutch, and includes a driven member 580, a first element 581 provided on the differential mechanism carrier 53, and a second element 582 provided on the driven member 580. The driven member 580 is supported by the differential case 52 in such a manner that it rotates integrally with the differential case 52 and is reciprocable along the third axis A3. The driven member 580 has a clutch ring 5802 including the second element 582 at an end on the X-direction X1 side. The driven member 580 is driven by a solenoid 59, which will be described later. Note that in other embodiments, the engagement mechanism 58 may be in the form of friction plates abutting against each other.

[0030] Fig. 3 is an explanatory diagram of the first element 581 (see Fig. 2) and the second element 582 (see Fig. 2), and is a perspective view showing the elements in an expanded state in which they are opened in a direction away from each other so that the meshing sides can be seen. In Fig. 3, x, y, and z coordinate axes for showing the relationship in the expanded state are associated with the differential mechanism carrier 53 and the clutch ring 5802 of the driven member 580. In this case, the z coordinate axis corresponds to the direction of the third axis A3.

[0031] The first element 581 and the second element 582 each have teeth 5810, 5820 for meshing around the third axis A3. The teeth 5810, 5820 are provided at a constant pitch along the circumferential direction around the third axis A3 in a manner that protrudes in the axial direction along the third axis A3. The pitches of the teeth 5810, 5820 may be the same. In this case, a phase shift may occur between the teeth 5810 of the first element 581 and the teeth 5820 of the second element 582, with the maximum phase shift corresponding to half the pitch of the teeth 5810, 5820. When the maximum shift occurs, the teeth 5810, 5820 are in a phase relationship that allows them to mesh with each other.

[0032] 3, the first element 581 and the second element 582 can transition between an engaged state and a disengaged state by relative axial movement along the third axis A3. In the engaged state in which the first element 581 and the second element 582 mesh with each other, transmission of rotational torque (i.e., transmission of power) about the third axis A3 is possible between the first element 581 and the second element 582.

[0033] In this embodiment, the driven member 580 reciprocates along the third axis A3, thereby realizing an engaged state (a state in which the first element 581 and the second element 582 mesh with each other) and a disengaged state of the engagement mechanism 58. Specifically, when the driven member 580 moves to an engaged position which is an end position on the X1 side in the X-direction, the engagement mechanism 58 is realized in an engaged state, and when the driven member 580 moves to a disengaged position which is an end position on the X2 side in the X-direction, the disengaged state of the engagement mechanism 58 is realized.

[0034] 2, the driven member 580 is biased by a spring element 5800 toward a non-engaged position on the X2 side in the X-direction. The spring element 5800 is expandable and contractible along the third axis A3, and applies a biasing force to the driven member 580 in the direction of the third axis A3, which is a biasing force toward the X2 side in the X-direction. Therefore, when the driven member 580 is not receiving a force from the solenoid 59 toward the X1 side in the X-direction (solenoid thrust force to be described later), the driven member 580 is located at the non-engaged position on the X2 side in the X-direction.

[0035] 2, the driven member 580 is connected to a mover 590 of the solenoid 59 so as to be movable in the X-direction X1 side in conjunction with the mover 590. The driven member 580 reciprocates along the third axis A3 via the mover 590. That is, the solenoid 59 drives the driven member 580 via the mover 590.

[0036] In this embodiment, the vehicle drive device 17 further includes a position sensor 171, as shown in schematic form in Figure 2. The position sensor 171 generates an output related to the position of the mover 590 or the driven member 580.

[0037] The detection method by the position sensor 171 in this embodiment is a magnetic type, but other methods (for example, an optical type) may also be used. In the example shown in Fig. 2, the position sensor 171 is provided in correspondence with the driven member 580. However, the position sensor 171 may also be provided in correspondence with the mover 590. The output of the position sensor 171 will be described later with reference to Fig. 5 etc.

[0038] [Control device] Next, a control system of the vehicle drive device 17 will be described. The vehicle drive device 17 includes a control device 173 (see FIG. 4) that controls the engagement mechanism 58 via a solenoid 59. The control device 173 is formed by a computer, and may be in the form of, for example, an ECU (Electronic Control Unit). The control device 173 may be realized by a control device that controls the rotating electric machine 1.

[0039] Fig. 4 is a schematic block diagram for explaining the function of the control device 173 of the vehicle drive device 17. In Fig. 4, in addition to the control device 173, the above-mentioned solenoid 59, position sensor 171, and rotating electric machine 1 are also shown. Fig. 5 is an explanatory diagram of the characteristics of an on / off signal generated based on the output of the position sensor 171. Fig. 6 is an explanatory diagram of the output characteristics of the position sensor 171. Fig. 7 is a table diagram showing the relationship between the output of the position sensor 171 and the state of the engagement mechanism 58 for each transition mode.

[0040] The control device 173 controls the engagement mechanism 58, and also controls the rotating electric machine 1 in coordination with the control of the engagement mechanism 58. In this case, the control device 173 may control the rotating electric machine 1 via another control device (not shown) that controls the rotating electric machine 1.

[0041] In this embodiment, the control device 173 detects various states of the engagement mechanism 58 based on the output of the position sensor 171 and controls the energization of the solenoid 59 .

[0042] The state of the engagement mechanism 58 may include various states as follows: That is, the state of the engagement mechanism 58 includes three states related to the stroke (or position) of the movable element 590: a completely released state (hereinafter also referred to as a "disengaged state"), a partially engaged state, and a completely engaged state (hereinafter also simply referred to as an "engaged state").

[0043] The non-engaged state corresponds to a state in which the first element 581 and the second element 582 are completely separated (mechanically separated state). The partially engaged state corresponds to a state in which the first element 581 and the second element 582 overlap but are not completely engaged (i.e., a state less than a full stroke). The engaged state corresponds to a state in which the first element 581 and the second element 582 are completely engaged (i.e., a state in which the driven member 580 is in an engaged position).

[0044] The state of the engagement mechanism 58 also includes an uplock state and a release failure state as states related to an abnormality.

[0045] The uplock state corresponds to a state in which the first element 581 and the second element 582 do not mesh with each other and their axial end faces (axial end faces of the toothed portions 5810, 5820) abut against each other (see state 600 in FIG. 8 described later). The uplock state occurs when the circumferential phase between the toothed portion 5810 of the first element 581 and the toothed portion 5820 of the second element 582 approximately matches. In the uplock state, the driven member 580 cannot move further toward the X1 side in the X-direction.

[0046] The incomplete release state corresponds to a state in which the engagement mechanism 58 is in a partially engaged state and the driven member 580 cannot move further toward the X2 side in the X direction under a condition in which no current is applied to the solenoid 59. In other words, the incomplete release state corresponds to a state in which the engagement mechanism 58 does not reach the released state from the partially engaged state.

[0047] In the example shown in FIG. 4, the control device 173 includes, as functions related to the engagement mechanism 58, a PWM control unit 1731, a current detection unit 1732, a sensor output generation unit 1733, a movement failure determination unit 1734, a retry control unit 1737, and an MG phase synchronization control unit 1738.

[0048] The functions of each part from the PWM control part 1731 to the MG phase synchronization control part 1738 may be realized by the CPU of a computer forming the control device 173 executing one or more programs in a memory device (e.g., a main memory device) of the computer.

[0049] When the engagement mechanism 58 should be in a disengaged state, the PWM control unit 1731 maintains the supply of current to the solenoid 59 in a stopped state (energization off state) until a transition command to the engaged state is received. When the PWM control unit 1731 receives a transition command to the engaged state, it starts supplying current to the solenoid 59 in response to the transition command. Specifically, when the PWM control unit 1731 receives a transition command to the engaged state, it supplies current to the solenoid 59 based on a preset duty ratio until the engagement mechanism 58 is in the engaged state. The duty ratio may be a constant value, or may be set to a relatively high value at the time of initial movement in order to improve the responsiveness of the initial movement.

[0050] If an uplock state is detected before the engagement mechanism 58 reaches a partially engaged state, the PWM control unit 1731 executes retry control for avoiding uplock. A method for detecting an uplock state will be described later. The retry control for avoiding uplock may be realized in cooperation with a retry control unit 1737, which will be described later. FIG. 8 is an explanatory diagram of the retry control for avoiding uplock, and a part of each of the first element 581 and the second element 582 is shown diagrammatically. In FIG. 8, state 600 indicates the uplock state, state 602 indicates a first stage state of the retry control for avoiding uplock, and state 604 indicates a second stage state of the retry control for avoiding uplock.

[0051] In the uplock state, state 600, the first element 581 and the second element 582 do not mesh with each other and their axial end faces come into contact with each other, and a frictional force is generated due to the thrust of the solenoid 59 (hereinafter referred to as the "solenoid thrust"). When this frictional force is relatively large, the first element 581 and the second element 582 rotate integrally while maintaining a state in which the circumferential phase between the toothed portion 5810 and the toothed portion 5820 is approximately matched. That is, co-rotation occurs. Therefore, in the retry control for avoiding the uplock, the PWM control unit 1731 may execute a control for reducing the solenoid thrust (hereinafter also referred to as the "thrust down control") as a first stage. This reduces the frictional force due to the solenoid thrust, and as shown in a schematic diagram of state 602, the co-rotation in the uplock state is eliminated. In the thrust down control, the duty ratio may be determined so that the solenoid thrust is slightly lower than the biasing force of the spring element 5800 (i.e., so that the driven member 580 moves slightly toward the X2 side in the X direction). This generates a difference in rotation speed between the rotating electric machine 1 side (first element 581) and the wheel W side (second element 582), and a phase difference occurs between the first element 581 and the second element 582. Next, in the retry control for avoiding uplock, the PWM control unit 1731 stops the thrust down control as a second stage and executes retry control to execute the original control again (control to realize the partial engagement state and the subsequent engagement state).

[0052] When the engagement mechanism 58 reaches the partially engaged state, the PWM control unit 1731 energizes the solenoid 59 so as to realize the engaged state of the engagement mechanism 58. At this time, the PWM control unit 1731 may variably control the magnitude of the current energized to the solenoid 59 by PWM control.

[0053] When the engagement mechanism 58 should be in the engaged state, the PWM control unit 1731 maintains (holds) the supply of current to the solenoid 59 until a command to transition to the disengaged state is received.

[0054] When the PWM control unit 1731 receives a command to transition to the disengaged state, it reduces the solenoid thrust toward 0 so that engagement mechanism 58 reaches the disengaged state. In this case, the duty ratio may be reduced to 0 all at once, or may be reduced gradually. When the solenoid thrust becomes 0 (i.e., when the power supply to solenoid 59 is stopped), the disengaged state is maintained by the biasing force of spring element 5800.

[0055] The current detection unit 1732 acquires information regarding the current flowing through the solenoid 59 (for example, the current flowing through the solenoid 59 and returning to the control device 173). The current flowing through the solenoid 59 may be detected by a current sensor (not shown).

[0056] The sensor output generating section 1733 generates a binary output signal (ON / OFF signal) in the manner shown in FIG.

[0057] As shown in Fig. 5, the on / off signal is on (an example of a first value) when the movable element 590 is at end position P1 (an example of a first end position) on the side that causes the engagement mechanism 58 to be in an engaged state, and is off (an example of a second value) when the movable element 590 is at end position P2 (an example of a second end position) on the side that causes the engagement mechanism 58 to be in a disengaged state. Note that this on / off may be reversed. That is, in a modified example, the on / off signal may be off when the movable element 590 is at end position P1 on the side that causes the engagement mechanism 58 to be in an engaged state, and off when the movable element 590 is at end position P2 on the side that causes the engagement mechanism 58 to be in a disengaged state.

[0058] In this embodiment, as shown in FIG. 5, the on / off signal has hysteresis between a transition mode from a non-engaged state to an engaged state and a transition mode from an engaged state to a non-engaged state. Specifically, in the transition mode from a non-engaged state to an engaged state, as shown by characteristic 501, when the mover 590 (and the driven member 580 accompanying it, the same below) moves from the end position P2 to the end position P1, the value of the output signal of the on / off signal switches from off to on at the intermediate position P3 (an example of a second intermediate position) (see arrow R1). Also, as shown by characteristic 502, when the mover 590 moves from the end position P1 to the end position P2, the value of the output signal of the on / off signal switches from on to off at the intermediate position P4 (an example of a first intermediate position) (see arrow R2). In this embodiment, the intermediate position P3 and the intermediate position P4 do not coincide with each other and are different from each other. At this time, the intermediate position P4 is closer to the end position P2 than the intermediate position P3. In this case, the intermediate position P4 may substantially coincide with the boundary position P6 between the partial engagement state and the disengaged state, or may be slightly closer to the end position P2 than the boundary position P6, as shown in Fig. 5. The intermediate position P3 may substantially coincide with the boundary position P7 between the partial engagement state and the engaged state, or may be slightly closer to the end position P1 than the boundary position P7, as shown in Fig. 5.

[0059] Such hysteresis characteristics of the on / off signal may be realized, for example, by using different thresholds Th1 and Th2 for the output of the position sensor 171 in a transition mode from a non-engaged state to an engaged state and a transition mode from an engaged state to a non-engaged state, as conceptually shown in FIG. 6. In FIG. 6, the horizontal axis shows the total stroke of the mover 590, and the vertical axis shows the output (analog electrical signal) of the position sensor 171. In FIG. 6, the level of the electrical signal from the position sensor 171 basically increases as the position of the mover 590 approaches the end position P1. In this embodiment, as shown in FIG. 6, the threshold Th1 is adapted to detect the intermediate position P3, and the threshold Th2 is adapted to detect the intermediate position P4. Note that the electrical signal from the position sensor 171 is conceptually shown non-linearly, but the actual characteristics may be different.

[0060] In a modified example, as described above, the on / off signal may be off when the movable element 590 is at end position P1 on the side that causes the engagement mechanism 58 to be in an engaged state, and may be on when the movable element 590 is at end position P2 on the side that causes the engagement mechanism 58 to be in a disengaged state. In this case, the output of the position sensor 171 may be in a mode in which the level of the electric signal increases as the position of the movable element 590 approaches end position P2, opposite to the mode shown in FIG.

[0061] Thus, in this embodiment, as shown in FIG. 7, between intermediate positions P3 and P4 (see L3 in FIG. 5) of the entire stroke of the movable member 590, the value of the on / off signal (on or off) differs between the transition mode from the non-engaged state to the engaged state and the transition mode from the engaged state to the non-engaged state.

[0062] The movement failure determination unit 1734 detects the above-mentioned uplock state and release failure state. In this embodiment, the movement failure determination unit 1734 detects the uplock state and release failure state in the manner shown in FIG. 7 by utilizing the hysteresis characteristic of the above-mentioned on / off signal.

[0063] Specifically, as shown in FIG. 7, in the transition mode from the non-engaged state to the engaged state, the value of the on / off signal is OFF between the intermediate position P4 and the intermediate position P3 (see L3 in FIG. 5) of the entire stroke of the movable member 590, similarly to the position range L2 from the end position P2 to the intermediate position P4. Here, if the engaged state is not realized within a predetermined time ΔT1 after the start of energization even though the solenoid 59 is energized, there is a high possibility that an uplock state is formed. Note that FIG. 5 shows a position P5 of the movable member 590 corresponding to the uplock state. In the uplock state, the movable member 590 stays at the position P5. Using this point, the movement failure determination unit 1734 may detect the uplock state when the value of the on / off signal does not switch from OFF to ON within a predetermined time ΔT1 after the start of energization. In this case, the predetermined time ΔT1 may be a time near the maximum value of the possible range of the elapsed time from the start of energization until the engaged state is realized, and may be adapted based on a test or the like.

[0064] Similarly, in the transition mode from the engaged state to the disengaged state, the value of the on / off signal is on between the intermediate position P3 and the intermediate position P4 (see L3 in FIG. 5) of the entire stroke of the movable member 590, as in the position range from the end position P1 to the intermediate position P3. Here, if the disengaged state is not realized within a predetermined time ΔT2 after the deactivation of the current even though the solenoid 59 is not energized, there is a high possibility that the release insufficient state is formed. Using this point, the movement failure determination unit 1734 may detect the release insufficient state when the value of the on / off signal does not switch from on to off within a predetermined time ΔT2 after the deactivation of the current. In this case, the predetermined time ΔT2 may be a time near the maximum value of the possible range of the elapsed time from the deactivation of the current to the realization of the disengaged state, and may be adapted based on a test or the like.

[0065] The retry control unit 1737 executes retry control for avoiding uplock when the engagement mechanism 58 is in an uplock state. The retry control unit 1737 may execute retry control for avoiding release failure when the engagement mechanism 58 is in a release failure state. The retry control for avoiding release failure may be realized by temporarily lowering the rotational torque of the rotating electric machine 1 to a relatively low value that is defined in advance. Alternatively or in addition to this, the retry control for avoiding release failure may be realized by energizing the solenoid 59 again and then stopping the energization of the solenoid 59.

[0066] The MG phase synchronization control unit 1738 controls the rotation speed of the rotating electric machine 1 so that the difference in rotation speed between the rotating electric machine 1 side (first element 581) and the wheel W side (second element 582) is within a predetermined range (for example, target value=0) (rotation speed synchronization control). The rotation speed synchronization control may be executed before the start of energization of the solenoid 59 in the transition mode from the non-engaged state to the engaged state, for example.

[0067] According to this embodiment, various states of the engagement mechanism 58 can be detected by using a relatively inexpensive position sensor 171. That is, in this embodiment, various states of the engagement mechanism 58 can be detected by generating hysteresis characteristics of an ON / OFF signal based on the output of the position sensor 171. The position sensor 171 is commercially available and inexpensive compared to position sensors capable of detecting each position of the mover 590.

[0068] In particular, according to this embodiment, as described above, the uplock state and the release failure state can be detected with high accuracy based on the presence or absence of current flow to the solenoid 59 (transition mode) and the value of the on / off signal from the position sensor 171.

[0069] Moreover, according to this embodiment, by setting the intermediate positions P3 and P4, which are the ON / OFF change positions related to the hysteresis characteristic of the ON / OFF signal, within an appropriate position range, it is possible to detect the uplock state and the release failure state while accurately detecting the transition to the engaged state and the transition to the non-engaged state. Specifically, in this embodiment, the intermediate position P3, which is the change position of the ON / OFF signal from OFF to ON, is set within the position range L2 (an example of the second position range) in which the engaged state is formed, as shown in FIG. 5. This allows the transition of the engagement mechanism 58 to the engaged state to be accurately detected based on the change of the ON / OFF signal from OFF to ON. Note that the intermediate position P3 may be set at a position within the position range L2 closer to the boundary position P7 than the end position P1. In this case, it is possible to accurately realize the separation between the partial engagement state (release failure state) and the engaged state in the transition mode from the non-engaged state to the engaged state. Similarly, in this embodiment, the intermediate position P4, which is the change position of the ON / OFF signal from ON to OFF, is set within the position range L1 (an example of the first position range) in which the non-engaged state is formed, as shown in FIG. 5. This makes it possible to accurately detect the transition of the engagement mechanism 58 to a disengaged state based on a change of the on / off signal from on to off. The intermediate position P4 may be set to a position within the positional range L1 that is closer to the boundary position P6 than the end position P2. In this case, it is possible to accurately distinguish between a partial engagement state (disengagement failure state) and an engaged state in the transition mode from the disengaged state to the engaged state.

[0070] Next, an example of the operation of this embodiment will be described with reference to Figures 9 and 10. In the following process flow diagrams (flowcharts), the order of processing steps may be changed as long as the relationship between input and output of each step is not lost.

[0071] Fig. 9 is a schematic flowchart showing an example of a process executed by the control device 173 in the transition mode from the non-engaged state to the engaged state. The process shown in Fig. 9 may be repeatedly executed at predetermined intervals in the transition mode from the non-engaged state to the engaged state.

[0072] In step S800, the control device 173 executes the rotation speed synchronization control, as described above in relation to the MG phase synchronization control unit 1738.

[0073] In step S802, the control device 173 judges whether or not the magnitude of the difference between the rotation speed of the wheel W side (second element 582) and the rotation speed of the rotating electric machine 1 side (first element 581) is smaller than a threshold value during the rotation speed synchronization control. The threshold value is a relatively small value for detecting the synchronous state. If the judgment result is "YES", the process proceeds to step S804, and otherwise the rotation speed synchronization control is continued.

[0074] In step S804, the control device 173 energizes the solenoid 59 (i.e., turns on the energization). Note that the energization method for transitioning to the engaged state is arbitrary, and may be, for example, as described above in relation to the PWM control unit 1731.

[0075] In step S806, the control device 173 determines whether or not the above-mentioned on / off signal based on the output of the position sensor 171 has changed from off to on. The above-mentioned on / off signal based on the output of the position sensor 171 is off in the disengaged state (see Figs. 5 and 7). Therefore, at the start of the processing shown in Fig. 9, the on / off signal is off. If the determination result is "YES", it is determined that a transition to an engaged state has been achieved (see Fig. 5), and the process proceeds to step S812. On the other hand, if the determination result is "NO", the process proceeds to step S808.

[0076] In step S808, the control device 173 determines whether or not a predetermined time ΔT1 has elapsed since the start of energization of the solenoid 59. The predetermined time ΔT1 is as described above in relation to the movement failure determination unit 1734. If the determination result is "YES", it is determined that an uplock state has been formed, and the process proceeds to step S810. On the other hand, if the determination result is "NO", the process returns to the process from step S804, and while maintaining energization of the solenoid 59, the process waits for the on / off signal to transition to on within the predetermined time ΔT1.

[0077] In step S810, the control device 173 executes retry control for avoiding uplock. The retry control for avoiding uplock is as described above in relation to the retry control unit 1737.

[0078] In step S812, the control device 173 maintains the supply of current to the solenoid 59 (indicated as "solenoid engagement holding current on" in FIG. 9) so as to maintain the engaged state of the engagement mechanism 58. Note that the supply of current to the solenoid 59 for maintaining the engaged state of the engagement mechanism 58 may be maintained until a transition command to a non-engaged state is received as described above (i.e., until the transition mode from the engaged state to the non-engaged state is entered).

[0079] In this manner, according to the process shown in FIG. 9, in the transition mode from the non-engaged state to the engaged state, it is possible to detect and avoid a state in which the movable member 590 is not properly moved (i.e., an uplock state) based on the above-mentioned on / off signal based on the output of the position sensor 171, while appropriately controlling the current supply to the solenoid 59.

[0080] Fig. 10 is a schematic flowchart showing an example of a process executed by the control device 173 in the transition mode from the engaged state to the disengaged state. The process shown in Fig. 10 may be repeatedly executed at predetermined intervals in the transition mode from the engaged state to the disengaged state.

[0081] In step S900, the control device 173 sets the solenoid 59 in a state in which it is not energized (off state).

[0082] In step S902, the control device 173 performs dog release torque control. The dog release torque control may be realized by controlling the rotating electric machine 1 so that the rotational torque transmitted between the first element 581 and the second element 582 is equal to or less than a threshold torque. In this case, the threshold torque may correspond to a vicinity of an upper limit value of a torque range in which the meshing between the first element 581 and the second element 582 is released.

[0083] In step S904, the control device 173 judges whether or not the above-mentioned on / off signal based on the output of the position sensor 171 has changed from on to off. The above-mentioned on / off signal based on the output of the position sensor 171 is on in the engaged state (see Figs. 5 and 7). Therefore, at the start of the process shown in Fig. 10, the on / off signal is on. If the judgment result is "YES", it is judged that a transition to a non-engaged state has been achieved (see Fig. 5), and the process ends. In this case, the state in which no current is applied to the solenoid 59 (off state) is maintained so that the non-engaged state of the engagement mechanism 58 is maintained. On the other hand, if the judgment result is "NO", the process proceeds to step S906.

[0084] In step S906, the control device 173 determines whether or not a predetermined time ΔT2 has elapsed since the power supply to the solenoid 59 was turned off. The predetermined time ΔT2 is as described above in relation to the movement failure determination unit 1734. If the determination result is "YES", it is determined that a release failure state has been formed, and the process proceeds to step S908. On the other hand, if the determination result is "NO", the process returns to the process from step S900, and while maintaining the power supply to the solenoid 59 in the OFF state, the process waits for the ON / OFF signal to transition to OFF within the predetermined time ΔT2.

[0085] In step S908, the control device 173 executes retry control for avoiding a release failure. The retry control for avoiding a release failure is as described above in relation to the retry control unit 1737.

[0086] In this manner, according to the processing shown in FIG. 10, in the transition mode from the engaged state to the disengaged state, it is possible to detect and avoid a poor movement state of the movable member 590 (i.e., a poor release state) based on the above-mentioned on / off signal based on the output of the position sensor 171, while appropriately controlling the current supply to the solenoid 59.

[0087] Although each embodiment has been described above in detail, the present invention is not limited to the specific embodiment, and various modifications and changes are possible within the scope of the claims. In addition, it is also possible to combine all or a plurality of the components of the above-described embodiments.

[0088] For example, in the above-described embodiment, the engagement mechanism 58 is provided in the differential gear mechanism 5, but is not limited thereto. That is, the engagement mechanism 58 may be provided at any position in the power transmission path from the rotating electric machine 1 to the wheels W. For example, as shown in FIG. 11, the engagement mechanism 58 may be provided in the counter gear mechanism 4. Specifically, the engagement mechanism 58 may be provided between the first counter gear 42 and the counter shaft 41. In this case, when the engagement mechanism 58 is in an engaged state, the first counter gear 42 and the counter shaft 41 rotate integrally, and when the engagement mechanism 58 is in a disengaged state, the first counter gear 42 and the counter shaft 41 are mechanically separated from each other. In FIG. 11, the engagement mechanism 58 is shown in a schematic manner such that one side is engaged and the other side is disengaged with respect to the second shaft A2.

[0089] In addition, in the above-described embodiment, the sensor output generating unit 1733 is realized by the control device 173 , but the function of the sensor output generating unit 1733 may be built into the position sensor 171 . [Explanation of symbols]

[0090] DESCRIPTION OF SYMBOLS 1··· rotating electric machine (power source), W··· wheel, 3··· input member, 18A, 18B··· output member, 58··· engagement mechanism, 59··· solenoid, 580··· driven member, 590··· mover, 171··· position sensor (sensor), 173··· control device, 1731··· PWM control unit (control unit), 1733··· sensor output generating unit (output generating unit), 1734··· movement failure determining unit (control unit)

Claims

1. an engagement mechanism that is provided between an input member and an output member that are provided in a power transmission path from a power source to a wheel, and that selectively forms an engaged state in which power can be transmitted between the input member and the output member and a disengaged state in which power cannot be transmitted between the input member and the output member; a solenoid having a movable element mechanically connected to the engagement mechanism, the solenoid moving a driven member of the engagement mechanism via the movable element between a first end position on a side where the engagement mechanism is brought into an engaged state and a second end position on a side where the engagement mechanism is brought into a disengaged state; a sensor that generates an electric signal according to the amount of movement of the movable element or the driven member; an output generating unit that generates a binary output signal based on the electrical signal from the sensor, the binary output signal having a first value when the driven member is at the first end position and a second value when the driven member is at the second end position; A control unit that controls energization of the solenoid based on the output signal from the output generating unit, the output generating unit generates the output signal such that, when the driven member moves from the first end position to the second end position, a value of the output signal switches from the first value to the second value at a first intermediate position between the first end position and the second end position, and, when the driven member moves from the second end position to the first end position, a value of the output signal switches from the second value to the first value at a second intermediate position between the first end position and the second end position; The first intermediate position is closer to the second end position than the second intermediate position.

2. the first intermediate position is set within a first position range of the driven member when the engagement mechanism is in the disengaged state, The vehicle drive device according to claim 1 , wherein the second intermediate position is set within a second position range of the driven member when the engagement mechanism is in the engaged state.

3. The vehicle drive device according to claim 2, wherein the control unit detects a poor movement state in which movement of the driven member to the first end position or the second end position is obstructed between the first intermediate position and the second intermediate position based on an output of the sensor.

4. 4. The vehicle drive device of claim 3, wherein the control unit detects the poor movement state when the output signal does not switch from the second value to the first value when transitioning the engagement mechanism from the disengaged state to the engaged state, or when the output signal does not switch from the first value to the second value when transitioning the engagement mechanism from the engaged state to the disengaged state.

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