JP2011143790A - Drive force transmission apparatus and control method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drive force transmission apparatus smoothly performing switching from a four-wheel drive state to a two-wheel drive state and switching from a two-wheel drive state to a four-wheel drive state, and a control method therefor. <P>SOLUTION: The drive force transmission apparatus includes: a propeller shaft 2 receiving a drive force of an engine 102 in a four-wheel drive vehicle 101 from a front differential case 111 and transmitting the drive force from a front wheel side to a rear wheel side between the front wheel side and the rear wheel side; a first drive force interruption unit 3 for connecting the propeller shaft 2 and the front differential case 111 so as to be disconnected; a second drive force interruption unit 4 for connecting the propeller shaft 2 and one of a pair of rear wheels 105 so that transmission torque becomes variable; and an ECU 5 for outputting a control signal for making the second drive force interruption unit 4 execute the connection before making the first drive force interruption unit 3 execute the connection and also making the second drive force interruption unit 4 execute the release of the connection before making the first drive force interruption unit 3 execute the release of the connection. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a driving force transmission device and a control method thereof in a four-wheel drive vehicle.

  Some conventional driving force transmission devices are mounted on a four-wheel drive vehicle that can be switched from a four-wheel drive state to a two-wheel drive state and from a two-wheel drive state to a four-wheel drive state. This type of driving force transmission device can transmit and block the driving force of a driving source to auxiliary driving wheels to which driving force is not transmitted during two-wheel drive (see, for example, Patent Document 1).

  The driving force transmission device described in Patent Document 1 is driven by a driving member coupled to a differential case so as to be able to transmit driving force, a first friction clutch that frictionally engages when the driving member is driven, and an axle shaft of an auxiliary driving wheel. A second friction clutch disposed between a driven member and a differential side gear shaft that are connected so as to be able to transmit force; and cam means that presses the second friction clutch by the operation of the first friction clutch; The side gear shaft and axle shaft are automatically connected during four-wheel drive, and the connection is automatically cut off during two-wheel drive.

JP 7-215081 A

  However, the driving force transmission device of Patent Document 1 is merely driven by the driving force of the propeller shaft, and cannot control the driving force transmission / cutoff timing and the driving force transmission amount. Therefore, depending on the configuration of the driving force interrupting portion on the driving force transmission upstream side of the propeller shaft, an impact or vibration may occur when switching between the four-wheel driving state and the two-wheel driving state.

  Accordingly, an object of the present invention is to provide a driving force transmission device and a control method therefor that can suppress impacts and vibrations when switching between a four-wheel drive state and a two-wheel drive state.

(1) In order to achieve the above object, the present invention receives the driving force of a driving source in a four-wheel drive vehicle from a rotating member, and the auxiliary driving wheel side and auxiliary driving wheel side out of the auxiliary driving wheel side from the auxiliary driving wheel side. A driving force transmission shaft that transmits to the driving wheel side, a first driving force intermittent portion that is disposed on the main driving wheel side, and that connects the driving force transmission shaft and the rotating member in an intermittent manner; and the driving force transmission A shaft and a pair of auxiliary drive wheels on the side of the auxiliary drive wheel, at least one of the auxiliary drive wheels is variably connected, and a second driving force intermittent portion disposed on the auxiliary drive wheel side; The connection by the driving force interrupting part is executed prior to the connection by the first driving force interrupting part, and the connection release by the second driving force interrupting part is executed prior to the connection release by the first driving force interrupting part. A driving force transmission device including a control unit is provided.

  According to this configuration, when the switching between the four-wheel drive and the two-wheel drive is performed by the control of the first driving force interrupting portion and the second driving force interrupting portion with variable transmission torque, the second driving force interrupting portion is connected or connected. The release is performed prior to the connection or release of the first driving force interrupting portion.

  The second driving force interrupting portion includes a first interrupting portion element connected to the driving force transmission shaft via a differential mechanism, and a second interrupting portion element connected to the one auxiliary driving wheel. If the driving force transmission device is configured as described above, the second driving force interrupting portion can be intermittently connected between the differential mechanism and the auxiliary driving wheel.

  The second driving force interrupting portion includes a first interrupting portion element connected to the driving force transmission shaft, and a second interrupting portion element connected to the pair of auxiliary driving wheels via a differential mechanism. If the driving force transmission device is configured as described above, the second driving force interrupting portion can be intermittently connected between the driving force transmission shaft and the differential mechanism.

(2) In order to achieve the above object, the present invention receives the driving force of the drive source in the four-wheel drive vehicle from the rotating member, and from the main drive wheel side to the auxiliary drive wheel side, the auxiliary drive wheel side from the auxiliary drive wheel side. A driving force transmission shaft that transmits to the driving wheel side, a first driving force intermittent portion that is disposed on the main driving wheel side, and that connects the driving force transmission shaft and the rotating member in an intermittent manner; and the driving force transmission A shaft and a pair of auxiliary drive wheels on the side of the auxiliary drive wheel, at least one of the auxiliary drive wheels is variably connected, and a second driving force intermittent portion disposed on the auxiliary drive wheel side; The connection by the driving force interrupting part is executed prior to the connection by the first driving force interrupting part, and the connection release by the second driving force interrupting part is executed prior to the connection release by the first driving force interrupting part. A four-wheel drive state of the four-wheel drive vehicle. At the time of switching to the two-wheel drive state, after releasing the connection by the second driving force interrupting portion, the connection release by the first driving force interrupting portion is executed, and the two-wheel driving state is changed to the four-wheel driving state. Provided is a control method for a driving force transmission device that performs connection by the first driving force interrupting unit after performing connection by the second driving force interrupting unit at the time of switching.

  According to this configuration, when the switching between the four-wheel drive and the two-wheel drive is performed by the control of the first driving force interrupting portion and the second driving force interrupting portion with variable transmission torque, the second driving force interrupting portion is connected or connected. The release is performed prior to the connection or release of the first driving force interrupting portion.

  Further, if the driving force transmission device is controlled so that the connection by the first driving force interrupting portion is executed based on the rotational speeds of the rotating member and the driving force transmission shaft, the four-wheel drive and the two-wheel drive can be performed more smoothly. Can be switched.

  According to the present invention, it is possible to suppress impacts and vibrations when switching between the four-wheel drive state and the two-wheel drive state.

The top view shown in order to demonstrate the outline of the vehicle carrying the drive force transmission device which concerns on the 1st Embodiment of this invention. Sectional drawing shown in order to demonstrate the principal part of the driving force transmission apparatus which concerns on the 1st Embodiment of this invention. The top view shown in order to demonstrate the outline of the vehicle carrying the driving force transmission apparatus which concerns on the 2nd Embodiment of this invention. Sectional drawing shown in order to demonstrate the principal part of the driving force transmission apparatus which concerns on the 2nd Embodiment of this invention.

[First embodiment]
FIG. 1 schematically shows a four-wheel drive vehicle. As shown in FIG. 1, a four-wheel drive vehicle 101 includes a driving force transmission device 1, an engine 102, a transmission 103, a pair of front wheels 104 as main drive wheels, and a pair of rear wheels 105a and 105b as auxiliary drive wheels. ing.

  The driving force transmission device 1 is disposed together with a front differential 106 and a rear differential 107 on a driving force transmission path from the transmission 103 side to the rear wheel side of the four-wheel drive vehicle 101, and a vehicle body (not shown) of the four-wheel drive vehicle 101. Equipped).

  The driving force transmission device 1 includes a propeller shaft (driving force transmission shaft) 2, a first driving force interrupting portion 3 and a second driving force interrupting portion 4. The driving state and the two-wheel driving state can be switched to the four-wheel driving state. Details of the driving force transmission device 1 will be described later.

  The front differential 106 accommodates a pair of side gears 109 connected to the front-wheel axle shaft 108, a pair of pinion gears 110 that mesh with the pair of side gears 109 with their gear axes orthogonal to each other, a pair of pinion gears 110, and a pair of side gears 109. It has a front differential case 111 and is disposed between the transmission 103 and the first driving force interrupting portion 3.

  The rear differential 107 includes a pair of side gears 113 coupled to the rear wheel axle shaft 112, a pair of pinion gears 114 that mesh with the pair of side gears 113 with the gear shaft orthogonal thereto, and a gear support member 115 that supports the pair of pinion gears 114. And a pinion gear support member 115, a pair of pinion gears 114, and a rear differential case 116 that accommodates a pair of side gears 113, and is disposed between the propeller shaft 2 and the second driving force interrupting portion 4. The side gear shaft 14 is connected to the left side gear 113 of the pair of side gears 113 so as not to be relatively rotatable.

  The engine 102 drives the pair of front wheels 104 by outputting a driving force to the pair of front wheel axle shafts 108 via the transmission 103 and the front differential 106.

  Further, the engine 102 transmits the driving force to the left rear wheel side axle shaft 112a via the transmission 103, the first driving force interrupting section 3, the propeller shaft 2, the rear differential 107, the side gear shaft 14, and the second driving force interrupting section 4. The left rear wheel 105a is output to the right rear wheel side axle shaft 112b via the transmission 103, the first driving force interrupting section 3, the propeller shaft 2 and the rear differential 107. Each of the rear wheels 105b is driven.

[Overall configuration of the driving force transmission device 1]
As shown in FIG. 1, the driving force transmission device 1 adds a vehicle ECU (Electronic Control Unit) 5 as a control unit to the propeller shaft 2, the first driving force intermittent portion 3 and the second driving force intermittent portion 4. It is roughly structured.

(Configuration of propeller shaft 2)
The propeller shaft 2 is disposed between the first driving force interrupting portion 3 and the second driving force interrupting portion 4. The propeller shaft 2 is configured to receive the driving force of the engine 102 from the front differential case 111 and transmit the driving force from the front wheel 104 side to the rear wheels 105a and 105b. A front wheel side gear mechanism 6 including a drive pinion 6 a and a ring gear 6 b that are meshed with each other is disposed at the front wheel side end of the propeller shaft 2. A gear mechanism 7 including a drive pinion 7a and a ring gear 7b that mesh with each other is disposed at the rear wheel side end of the propeller shaft 2.

(Configuration of the first driving force interrupting section 3)
The first driving force interrupting section 3 is formed of, for example, a dog clutch, is disposed on the front wheel 104 side of the four-wheel drive vehicle 101, and is connected to the ECU 5 via an actuator (not shown). And the 1st driving force interruption part 3 is comprised so that the propeller shaft 2 and the front differential case 111 may be connected intermittently.

(Configuration of the second driving force interrupting portion 4)
FIG. 2 shows the second driving force interrupting portion 4. As shown in FIG. 2, the second driving force interrupting portion 4 is composed of, for example, a composite clutch having a multi-plate clutch 8, an electromagnetic clutch 9, and a cam mechanism 10, and is disposed on the rear wheel 105a side of the four-wheel drive vehicle 101. And it is accommodated in the differential carrier 11.

  And the 2nd driving force interruption part 4 is comprised so that the side gear shaft 14 and the left rear wheel side axle shaft 112a may be connected intermittently.

  That is, at the time of connection by the second driving force interrupting portion 4, the left rear wheel side axle shaft 112a and the propeller shaft 2 are connected to the right rear wheel side axle shaft 112b via the gear mechanism 7, the rear differential 107 and the side gear shaft 14. The propeller shaft 2 is connected to the propeller shaft 2 via the gear mechanism 7 and the rear differential 107 so that torque can be transmitted.

  On the other hand, when the connection by the second driving force interrupting portion 4 is released, the connection between the left rear wheel side axle shaft 112a and the propeller shaft 2 is cut off, and accordingly, the right rear wheel side axle shaft 112b is also connected from the propeller shaft 2. Torque is not transmitted. The reason why the torque is not transmitted to the right rear wheel axle shaft 112b is due to the characteristic of the general differential device that when one side gear idles, the torque is not transmitted to the other side gear.

  The multi-plate clutch 8 includes a friction type main clutch having a plurality of inner clutch plates 8a and a plurality of outer clutch plates 8b. The multi-plate clutch 8 includes a housing 12 as a first interrupting element and an inner shaft 13 as a second interrupting element. Arranged between. The multi-plate clutch 8 frictionally engages the inner and outer clutch plates adjacent to each other out of the inner clutch plate 8a and the outer clutch plate 8b, and releases the frictional engagement between the housing 12 and the inner shaft 13. It is configured to be connected so as to be intermittent (torque transmission).

  The housing 12 is connected to the side gear shaft 14 so as not to rotate relative to the side gear shaft 14 by, for example, spline fitting, and is supported in the differential carrier 11 so as to be rotatable around the axis of the left rear wheel axle shaft 112a. The inner shaft 13 is disposed on the inner periphery of the housing 12 and is connected to the rear wheel axle shaft 112 so as not to be relatively rotatable by, for example, spline fitting.

  The electromagnetic clutch 9 has a coil 9 a and an armature cam 9 b and is disposed on the rotation axis of the housing 12. The electromagnetic clutch 9 is configured to move the armature cam 9b to the coil 9a side by the generation of electromagnetic force by the coil 9a and to connect the armature cam 9b to the housing 12.

  The cam mechanism 10 includes an armature cam 9b as a cam member, and a main cam 10a parallel to the armature cam 9b along the rotation axis of the housing 5 and a cam follower 10b interposed between the main cam 10a and the armature cam 9b. And housed in the housing 12. The cam mechanism 10 is configured such that the armature cam 9b receives the rotational force from the housing 12 by energization of the coil 9a and converts it into a pressing force that becomes the clutch force of the multi-plate clutch 8. As the amount of current supplied to the coil 9a increases, the frictional force between the armature cam 9b and the housing 12 increases, and the main cam 10a presses the multi-plate clutch 8 more strongly. That is, the pressing force of the multi-plate clutch 8 can be controlled in accordance with the amount of current supplied to the coil 9a, and the second driving force interrupting portion 4 is variable in transmission torque.

(Configuration of ECU 5)
As shown in FIG. 1, the ECU 5 is mounted on the vehicle body of the four-wheel drive vehicle 101 and is connected to the actuator of the first driving force interrupting portion 3 and the electromagnetic clutch 9 of the second driving force interrupting portion 4. The ECU 5 is connected to a rotation sensor 15 that detects the rotation speed of the front differential case 111 and a rotation sensor 16 that detects the rotation speed of the propeller shaft 2.

  The ECU 5 inputs the output signal S3 from the rotation sensor 15 and the output signal S4 from the rotation sensor 16 when the four-wheel drive vehicle 101 is switched from the two-wheel drive state to the four-wheel drive state while the four-wheel drive vehicle 101 is traveling. The control signals S1 and S2 for executing the connection by the force interrupting unit 4 prior to the connection by the first driving force interrupting unit 3 are sent to the actuator of the first driving force interrupting unit 3 and the second driving force interrupting unit 4 respectively. It is configured to output to the electromagnetic clutch 9.

  During traveling in the two-wheel drive state, the connection by the first driving force interrupting portion 3 and the second driving force interrupting portion 4 is released, and the propeller shaft 2 is in a non-rotating state. However, even in this state, the rear wheels 105a and 105b rotate as driven wheels as the four-wheel drive vehicle 101 travels. Here, when the amount of current supplied to the coil 9a is gradually increased and the connection by the second driving force interrupting portion 4 is executed, the rotational torque of the rear wheels 105a and 105b is transmitted to the propeller shaft 2, and the propeller shaft 2 is Rotate. Next, the rotation speed of the front differential case 111 is detected by the rotation sensor 15 and the rotation speed of the propeller shaft 2 is detected by the rotation sensor 16, and the ECU 5 confirms that the difference between the rotation speeds is equal to or less than a predetermined threshold value. Then, the connection by the first driving force interrupting unit 3 is executed. In addition, it is desirable to set the rate of increase in the amount of energization to the coil 9a to such an extent that the occupant does not sense impact or vibration.

  As a result, the propeller shaft 2 is coupled to the front differential case 111 by the rotation thereof with a small rotational speed difference, and the four-wheel drive vehicle 101 can be smoothly switched from the two-wheel drive state to the four-wheel drive state while the four-wheel drive vehicle 101 is traveling. Is called.

  Further, the ECU 5 cancels the connection by the second driving force interrupting unit 4 when the four-wheel driving vehicle 101 is traveling from the four-wheel driving state to the two-wheel driving state by releasing the connection by the first driving force interrupting unit 3. Are also configured to output control signals S5 and S6 to be executed in advance to the actuator of the first driving force interrupting portion 3 and the electromagnetic clutch 9 of the second driving force interrupting portion 4, respectively.

  At the time of this switching, when the amount of current supplied to the coil 9a is gradually decreased and the connection by the second driving force interrupting portion 4 is released, torque transmission from the propeller shaft 2 to the rear wheel axle shafts 105a and 105b is cut off. The Then, the twist of the propeller shaft 2 that has occurred at the time of torque transmission is released. Thereafter, the release of the connection by the first driving force interrupting unit 3 is executed. It should be noted that it is desirable to set the rate of decrease in the energization amount to the coil 9a to such an extent that the occupant does not sense impact or vibration.

  As a result, when the four-wheel drive vehicle 101 is switched from the four-wheel drive state to the two-wheel drive state, the connection between the propeller shaft 2 and the front differential case 111 is cut off in a state where a load due to the twist of the propeller shaft 2 does not act. Switching from the four-wheel drive state to the two-wheel drive state during traveling of the wheel drive vehicle 101 is performed smoothly.

[Operation of Driving Force Transmission Device 1]
Next, the operation of the driving force transmission apparatus shown in the first embodiment will be described with reference to FIGS.

  For example, when the four-wheel drive vehicle 101 is in a steady traveling state where the vehicle travels straight at a constant speed, the ECU 5 releases the connection by the first driving force interrupting unit 3 and the second driving force interrupting unit 4 in order to reduce driving resistance and improve fuel efficiency. To do. In this state, the propeller shaft 2 does not rotate, the driving force of the engine 102 is transmitted to the front differential 106 via the transmission 103, and further from the front differential 106 to the pair of front wheels 104 via the pair of front wheel side axle shafts 108. Communicated.

  In this case, since the coil 9a of the electromagnetic clutch 9 in the second driving force interrupting portion 4 is in a non-energized state, a magnetic circuit based on the coil 9a is not formed, and the armature cam 9b moves to the coil 9a side and moves to the housing. 12 is not connected. Accordingly, the cam mechanism 10 does not generate a pressing force as the clutch force of the multi-plate clutch 8, and the inner clutch plate 8a and the outer clutch plate 8b of the multi-plate clutch 8 are not frictionally engaged with each other.

  In order to switch the four-wheel drive vehicle 101 in such a two-wheel drive state to the four-wheel drive state, first, torque transmission between the propeller shaft 2 and the pair of rear wheel axle shafts 112a and 112b is performed by the second driving force interrupting portion 4. The front differential case 111 and the propeller shaft 2 are connected so as to be able to transmit torque by the first driving force interrupting section 3. At this time, the ECU 5 receives the output signal S3 from the rotation sensor 15 and the output signal S4 from the rotation sensor 16, respectively, and after the rotation speed indicated by the two output signals has reached a predetermined threshold, the first driving force is interrupted. The control signal S1 is output to the actuator of the unit 3.

  For this reason, the driving force of the engine 102 is transmitted to the propeller shaft 2 via the transmission 103, the front differential case 111, the first driving force intermittent portion 3 and the gear mechanism 6, and further from the propeller shaft 2 to the gear mechanism 7, the rear differential 107, and It is transmitted to the rear wheels 105a and 105b via the rear wheel side axle shafts 112a and 112b.

  Here, the operation of the second driving force interrupting section 4 will be described in detail. When the coil 9 a is energized by the output of the control signal S <b> 2 of the ECU 5, a magnetic circuit with the coil 9 a as a base point is formed, and the armature cam 9 b moves in a direction to be connected to the housing 12. Therefore, the armature cam 9b frictionally slides on the housing 12, and the rotational force of the housing 12 is transmitted to the armature cam 9b.

  Along with this, the armature cam 9b rotates, and this rotational force is converted into a pressing force that becomes the clutch force of the multi-plate clutch 8 by the cam action generated in the cam mechanism 10, and this pressing force causes the inside and outside of the multi-plate clutch 8 to The main cam 10a moves in a direction in which the clutch plates are frictionally engaged.

  As a result, the inner and outer clutch plates of the multi-plate clutch 8 are frictionally engaged with each other, and the housing 12 and the inner shaft 13 are coupled so as to transmit torque.

  In this four-wheel drive state, the amount of torque transmitted to the rear wheels 105a and 105b can be controlled by adjusting the pressing force of the multi-plate clutch 8 by increasing or decreasing the energization amount to the coil 9a. That is, the ECU 5 controls the distribution of driving force between the front wheels 104, 104 and the rear wheels 105a, 105b by increasing / decreasing the energization amount to the coil 9a according to the vehicle running state such as the wheel speed and steering angle of each wheel.

  On the other hand, in order to switch the four-wheel drive vehicle 101 in the four-wheel drive state to the two-wheel drive state, the connection between the one rear wheel side axle shaft 112 and the propeller shaft 2 is released by the second driving force interrupting section 4 and then continues. The connection between the propeller shaft 2 and the front differential case 111 is released. At this time, the control signal S6 is output from the ECU 5 to the electromagnetic clutch 9 of the second driving force interrupting section 4, and the control signal S5 is output to the actuator of the first driving force interrupting section 3.

  For this reason, the rotational driving force of the engine 102 is not transmitted to the propeller shaft 2 via the transmission 103, the front differential case 111, the first driving force intermittent portion 3 and the gear mechanism 6.

[Effect of the first embodiment]
According to the first embodiment described above, the following effects can be obtained.

(1) The four-wheel drive vehicle 101 can be smoothly switched from the four-wheel drive state to the two-wheel drive state and from the two-wheel drive state to the four-wheel drive state.

(2) Since the second driving force interrupting section 4 can adjust the pressing force of the multi-plate clutch 8 according to the energizing amount to the coil 9a, the energizing amount is gradually increased when switching between the four-wheel driving state and the two-wheel driving state. By reducing it, it is possible to further suppress the impact and vibration at the time of switching the driving state.

[Second Embodiment]
Next, a driving force transmission device according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 3 shows an outline of a four-wheel drive vehicle. FIG. 4 shows the second driving force interrupting portion. 3 and 4, members that are the same as or equivalent to those in FIGS. 1 and 2 are given the same reference numerals, and detailed descriptions thereof are omitted.

  As shown in FIGS. 3 and 4, the driving force transmission device 21 according to the second embodiment of the present invention has a second driving force interrupting portion 22 on the rear wheel side, and the second driving force interrupting portion 22 is The housing 12 as a first intermittent element connected to the propeller shaft 2 via the gear mechanism 7 and the second connected to the pair of rear wheels 105 via the pair of rear axle shafts 112 and the rear differential 107. It is characterized in that it has an inner shaft 13 as an intermittent element.

  The housing 12 includes a first housing element 12A that accommodates the multi-plate clutch 8, the electromagnetic clutch 9, and the cam mechanism 10, and a second housing element 12B that accommodates the rear differential 107, and is fixed to the ring gear 7b of the gear mechanism 7. ing. The inner shaft 13 is connected to the rear differential case 116 so as not to be relatively rotatable by spline fitting. The rear differential 107 has a pair of side gears 113 connected to the rear wheel axle shaft 112 by spline fitting.

[Operation of Driving Force Transmission Device 21]
Next, the operation of the driving force transmission apparatus shown in the second embodiment will be described with reference to FIGS.

  For example, when the four-wheel drive vehicle 101 is in a steady traveling state where the vehicle travels straight at a constant speed, the ECU 5 releases the connection by the first driving force interrupting unit 3 and the second driving force interrupting unit 22 in order to reduce the running resistance and improve the fuel consumption. To do. In this state, the propeller shaft 2 does not rotate, the driving force of the engine 102 is transmitted to the front differential 106 via the transmission 103, and further from the front differential 106 to the pair of front wheels 104 via the pair of front wheel side axle shafts 108. Communicated.

  In this case, since the coil 9a of the electromagnetic clutch 9 in the second driving force interrupting portion 22 is in a non-energized state, a magnetic circuit based on the coil 9a is not formed, and the armature cam 9b moves toward the coil 9a and moves to the housing. 12 is not connected. Accordingly, the cam mechanism 10 does not generate a pressing force as the clutch force of the multi-plate clutch 8, and the inner clutch plate 8a and the outer clutch plate 8b of the multi-plate clutch 8 are not frictionally engaged with each other.

  In order to switch the four-wheel drive vehicle 101 in such a two-wheel drive state to the four-wheel drive state, first, the propeller shaft 2 and the rear wheel side axle shaft 112 are connected by the second driving force interrupting portion 22 so as to transmit torque. Subsequently, the front differential case 111 and the propeller shaft 2 are connected by the first driving force interrupting portion 3 so that torque can be transmitted. At this time, the ECU 5 receives the output signal S3 from the rotation sensor 15 and the output signal S4 from the rotation sensor 16, respectively, and after the rotation speed indicated by the two output signals has reached a predetermined threshold, the first driving force is interrupted. The control signal S1 is output to the actuator of the unit 3.

  For this reason, the rotational driving force of the engine 102 is transmitted to the propeller shaft 2 via the transmission 103, the front differential case 111, the first driving force interrupting portion 3 and the gear mechanism 6, and further from the propeller shaft 2 to the gear mechanism 7 and the rear differential 107. And, it is transmitted to the rear wheel 105 through the rear wheel side axle shaft 112.

  Here, the operation of the second driving force interrupting portion 22 will be described in detail. When the coil 9 a is energized by the output of the control signal S <b> 2 of the ECU 5, a magnetic circuit with the coil 9 a as a starting point is formed, and the armature cam 9 b moves in a direction to be connected to the housing 12. Therefore, the armature cam 9b frictionally slides on the housing 12, and the rotational force of the housing 12 is transmitted to the armature cam 9b.

  Along with this, the armature cam 9b rotates, and this rotational force is converted into a pressing force that becomes the clutch force of the multi-plate clutch 8 by the cam action generated in the cam mechanism 10, and this pressing force causes the inside and outside of the multi-plate clutch 8 to The main cam 10a moves in a direction in which the clutch plates are frictionally engaged.

  As a result, the inner and outer clutch plates of the multi-plate clutch 8 are frictionally engaged with each other, and the housing 12 and the inner shaft 13 are coupled so as to transmit torque. As a result, torque can be transmitted between the propeller shaft 2 and the rear differential case 116 of the rear differential 107.

  In this four-wheel drive state, the amount of torque transmitted to the rear wheel 105 can be controlled by adjusting the pressing force of the multi-plate clutch 8 by increasing or decreasing the energization amount to the coil 9a. That is, the ECU 5 controls the distribution of driving force between the pair of front wheels 104 and the pair of rear wheels 105 by increasing or decreasing the energization amount to the coil 9a according to the vehicle running state such as the wheel speed and steering angle of each wheel.

  On the other hand, to switch the four-wheel drive vehicle 101 in the four-wheel drive state to the two-wheel drive state, the connection between the rear wheel side axle shaft 112 and the propeller shaft 2 is released by the second drive force interrupting portion 22 and the first drive continuously. The connection between the propeller shaft 2 and the front differential case 111 is released by the driving force interrupting portion 3. At this time, the control signal S6 is output from the ECU 5 to the electromagnetic clutch 9 of the second driving force interrupting section 22, and the control signal S5 is output to the actuator of the first driving force interrupting section 3.

  For this reason, the rotational driving force of the engine 102 is not transmitted to the propeller shaft 2 via the transmission 103, the front differential case 111, the first driving force intermittent portion 3 and the gear mechanism 6.

[Effect of the second embodiment]
According to the second embodiment described above, the same effects as those shown in the first embodiment can be obtained.

  As mentioned above, although the driving force transmission device of the present invention has been described based on the above embodiment, the present invention is not limited to the above embodiment, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

(1) In each of the above embodiments, the case where the second driving force interrupting portions 4 and 22 are composed of a composite clutch including the multi-plate clutch 8, the electromagnetic clutch 9, and the cam mechanism 10 has been described, but the present invention is limited to this. For example, the multi-plate clutch 8, the electromagnetic clutch 9, and the cam mechanism 10 may be composed of a composite clutch in which a pilot clutch is added.

(2) In each of the above embodiments, the first driving force interrupting portion 3 is configured as a dog clutch (meshing clutch). However, the present invention is not limited thereto, and the first driving force interrupting portion 3 may be configured as a multi-plate clutch. .

(3) In the first embodiment, the second driving force interrupting portion 4 is disposed only between the left rear wheel side axle shaft 112a and the rear differential 107. However, the second driving force interrupting portion 4 is disposed on the right rear side. You may arrange | position also between the wheel side axle shaft 112b and the rear differential 107. FIG.

  DESCRIPTION OF SYMBOLS 1 ... Driving force transmission apparatus, 2 ... Propeller shaft, 3 ... 1st driving force intermittent part, 4 ... 2nd driving force intermittent part, 5 ... ECU, 6 ... Gear mechanism, 6a ... Drive pinion, 6b ... Ring gear, 7 ... Gear mechanism, 7a ... Drive pinion, 7b ... Ring gear, 8 ... Multi-plate clutch, 8a ... Inner clutch plate, 8b ... Outer clutch plate, 9 ... Electromagnetic clutch, 9a ... Coil, 9b ... Armature cam, 10 ... Cam mechanism, 10a ... main cam, 10b ... cam follower, 11 ... differential carrier, 12 ... housing, 12A ... first housing element, 12B ... second housing element, 13 ... inner shaft, 14 ... side gear shaft, 15, 16 ... rotation sensor, 21 ... drive Force transmission device, 22 ... second driving force interrupting part, 101 ... four-wheel drive vehicle, 102 103, transmission, 104, front wheel, 105, 105a, 105b ... rear wheel, 106 ... front differential, 107 ... rear differential, 108 ... front wheel side axle shaft, 109 ... side gear, 110 ... pinion gear, 111 ... front differential case, 112 , 102a, 102b ... rear wheel side axle shaft, 113 ... side gear, 114 ... pinion gear, 115 ... pinion gear support member, 116 ... rear differential case

Claims (5)

A driving force transmission shaft that receives a driving force of a driving source in a four-wheel drive vehicle from a rotating member and transmits the driving force from the main driving wheel side to the auxiliary driving wheel side among the main driving wheel side and the auxiliary driving wheel side;
The driving force transmission shaft and the rotating member are connected in an intermittent manner, and a first driving force interrupting portion disposed on the main driving wheel side,
A second driving force interrupting portion disposed on the auxiliary driving wheel side, wherein the driving force transmission shaft and at least one auxiliary driving wheel of the pair of auxiliary driving wheels on the auxiliary driving wheel side are variably connected to each other; ,
The connection by the second driving force interrupting part precedes the connection by the first driving force interrupting part, and the connection release by the second driving force interrupting part precedes the connection release by the first driving force interrupting part. A driving force transmission device including a control unit to be executed.   The second driving force interrupting portion includes a first interrupting portion element connected to the driving force transmission shaft via a differential mechanism, and a second interrupting portion element connected to the one auxiliary driving wheel. The driving force transmission device according to 1.   The second driving force interrupting portion includes a first interrupting portion element connected to the driving force transmission shaft and a second interrupting portion element connected to the pair of auxiliary driving wheels via a differential mechanism. The driving force transmission device according to 1. A driving force transmission shaft that receives a driving force of a driving source in a four-wheel drive vehicle from a rotating member and transmits the driving force from the main driving wheel side to the auxiliary driving wheel side among the main driving wheel side and the auxiliary driving wheel side;
The driving force transmission shaft and the rotating member are connected in an intermittent manner, and a first driving force interrupting portion disposed on the main driving wheel side,
A second driving force interrupting portion disposed on the auxiliary driving wheel side, wherein the driving force transmission shaft and at least one auxiliary driving wheel of the pair of auxiliary driving wheels on the auxiliary driving wheel side are variably connected to each other; ,
The connection by the second driving force interrupting part precedes the connection by the first driving force interrupting part, and the connection release by the second driving force interrupting part precedes the connection release by the first driving force interrupting part. And a control unit to be executed
After performing the release of the connection by the second driving force interrupting portion at the time of switching from the four-wheel drive state to the two-wheel drive state of the four-wheel drive vehicle, executing the release of the connection by the first driving force interrupting portion,
A control method for a driving force transmission device, wherein, after switching from the two-wheel drive state to the four-wheel drive state, the connection by the second driving force interrupting unit is executed after the connection by the second driving force interrupting unit.   The control method of the driving force transmission device according to claim 4, wherein the connection by the first driving force interrupting portion is executed based on the rotational speeds of the rotating member and the driving force transmission shaft.

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