JP2005145094A - Driving force distribution device of four-wheel drive vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To generate, by a simple structure, a specified hydraulic pressure for engaging the hydraulic clutch of the driving force distribution device of a four-wheel drive vehicle. <P>SOLUTION: The four-wheel drive vehicle V comprises the hydraulic clutch 20 distributing a drive force from front wheels Wf to rear wheels Wr, a hydraulic pump 30 generating hydraulic pressure for engaging the hydraulic clutch 20, and a control means 48 directly controlling hydraulic pressure generated by the hydraulic pump 30 based on the traveling state of the vehicle V. Since a control means 48 directly controls hydraulic pressure generated by the hydraulic pump 30, accumulators and regulators, which were required before, can be eliminated and the number of parts and cost can be reduced. Also, since a super-magnetostrictor 35 capable of generating a high output with low voltage and having high responsiveness is used in the hydraulic pump 30, not only a power consumption, weight, and space can be reduced less than in a case where the hydraulic pump 30 is driven by an electric motor but also the generated hydraulic pressure can be accurately controlled. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a driving force distribution device for a four-wheel drive vehicle capable of distributing a part of driving force transmitted from a driving source to main driving wheels to sub driving wheels via a hydraulic clutch.

In a four-wheel drive vehicle capable of switching between a rear wheel drive state in which the engine driving force is transmitted only to the rear wheels and a four wheel drive state in which the engine driving force is transmitted to both the front wheels and the rear wheels. The hydraulic clutch placed in the driving force transmission system is engaged with the hydraulic pressure generated by the hydraulic pump driven by the motor, the accumulator that accumulates the hydraulic pressure generated by the hydraulic pump, and the regulator that regulates the hydraulic pressure accumulated in the accumulator This is known from Patent Document 1 below.
Japanese Patent No. 2913955

  However, in the above-mentioned Patent Document 1, the hydraulic pressure generated by the hydraulic pump is temporarily accumulated in an accumulator and is regulated by a regulator in order to obtain a predetermined hydraulic pressure for fastening the hydraulic clutch. There is a problem that the number of parts and the cost increase due to the necessity of a regulator.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to generate a predetermined hydraulic pressure for fastening a hydraulic clutch of a driving force distribution device of a four-wheel drive vehicle with a simple structure.

  In order to achieve the above object, according to the first aspect of the present invention, four wheels that can distribute a part of the driving force transmitted from the drive source to the main drive wheels to the sub drive wheels via the hydraulic clutch. In a driving force distribution device for a driving vehicle, a hydraulic pump that generates hydraulic pressure for engaging a hydraulic clutch, a traveling state detection unit that detects a traveling state of the vehicle, and a hydraulic pressure based on the traveling state of the vehicle detected by the traveling state detection unit Proposed a driving force distribution device for a four-wheel drive vehicle, comprising a control means for controlling the distribution of the driving force between the main driving wheel and the auxiliary driving wheel by directly controlling the hydraulic pressure generated by the pump Is done.

  According to the invention described in claim 2, in addition to the structure of claim 1, a driving force distribution device for a four-wheel drive vehicle is proposed, in which the hydraulic pump is driven by a giant magnetostrictive element. .

  According to the invention described in claim 3, in addition to the configuration of claim 1 or claim 2, the hydraulic pressure for detecting the hydraulic pressure of the discharge oil passage connecting the discharge port of the hydraulic pump and the oil chamber of the hydraulic clutch. A driving force distribution device for a four-wheel drive vehicle is proposed, which includes a sensor, and the control means controls the operation of the hydraulic pump so that the hydraulic pressure detected by the hydraulic sensor matches the target hydraulic pressure.

  According to the invention described in claim 4, in addition to the structure of claim 3, a four-wheel drive characterized in that a variable orifice is provided in a discharge oil passage connecting an oil chamber of a hydraulic clutch and a reservoir. A vehicle driving force distribution device is proposed.

  According to the fifth aspect of the present invention, in addition to the configuration of the second aspect, the hydraulic pump includes a coil that generates a magnetic field for expanding and contracting the giant magnetostrictive element, and the control means is a magnitude of a current supplied to the coil. A driving force distribution device for a four-wheel drive vehicle is proposed.

  According to the invention described in claim 6, in addition to the configuration of claim 2, the hydraulic pump includes a coil that generates a magnetic field for expanding and contracting the giant magnetostrictive element, and the control means sets the frequency of the current supplied to the coil. A driving force distribution device for a four-wheel drive vehicle characterized by control is proposed.

  According to a seventh aspect of the present invention, in addition to the configuration of any one of the first to sixth aspects, a hydraulic clutch is provided for each of the left and right auxiliary drive wheels. A driving force distribution device for a wheel drive vehicle is proposed.

  According to the invention described in claim 8, in addition to the structure of claim 1, the first hydraulic pump that supplies the hydraulic oil to the hydraulic clutch and the second hydraulic pump that sucks the hydraulic oil from the hydraulic clutch are provided. A driving force distribution device for a four-wheel drive vehicle characterized by being provided is proposed.

  According to the ninth aspect of the present invention, in addition to the configuration of the seventh aspect, the hydraulic oil supplied to the hydraulic clutch provided on each of the left and right auxiliary drive wheels is controlled by a three-way valve. A driving force distribution device for a four-wheel drive vehicle is proposed.

  According to the invention described in claim 10, in addition to the structure of claim 7, the hydraulic clutches respectively provided on the left and right auxiliary drive wheels are the left and right clutches arranged so as to sandwich the common oil chamber. A driving force distribution device for a four-wheel drive vehicle characterized by being fastened by a piston is proposed.

  The engine E of the embodiment corresponds to the drive source of the present invention, the front wheel Wf of the embodiment corresponds to the main drive wheel of the present invention, the rear wheel Wr of the embodiment corresponds to the auxiliary drive wheel of the present invention, The first hydraulic sensor 40 of the embodiment corresponds to the hydraulic sensor of the present invention, and the front wheel speed sensor 49, the rear wheel speed sensor 50, the yaw rate sensor 51, and the lateral acceleration sensor 52 of the embodiment are used as the traveling state detection means of the present invention. Correspond.

  According to the configuration of the first aspect, the hydraulic pressure generated by the hydraulic pump is controlled by the control unit based on the traveling state of the vehicle detected by the traveling state detecting unit in order to engage the hydraulic clutch of the driving force distribution device of the four-wheel drive vehicle. Since direct control is performed, accumulators and regulators that have been necessary in the past are unnecessary, and the number of parts and cost can be reduced.

  According to the configuration of the second aspect, since the hydraulic pump is driven by the giant magnetostrictive element that can generate a high output at a low voltage and has high responsiveness, the power consumption compared to the case where the hydraulic pump is driven by an electric motor. Not only can the weight and space be reduced, but also the generated hydraulic pressure can be accurately controlled.

  According to the configuration of the third aspect, the oil pressure of the discharge oil passage connecting the discharge port of the hydraulic pump and the oil chamber of the hydraulic clutch is detected by the oil pressure sensor so that the oil pressure detected by the oil pressure sensor matches the target oil pressure. Since the control means controls the operation of the hydraulic pump, the hydraulic pressure generated by the hydraulic pump can be feedback-controlled with high accuracy.

  According to the configuration of the fourth aspect, since the variable orifice is provided in the discharge oil passage connecting the oil chamber and the reservoir of the hydraulic clutch, the magnitude of the fastening force of the hydraulic clutch and the engagement can be changed by changing the opening of the variable orifice. The rise of force can be controlled arbitrarily.

  According to the configuration of the fifth aspect, since the giant magnetostrictive element is reciprocated and expanded by controlling the magnitude of the current supplied to the coil of the hydraulic pump by the control means, the discharge amount of the hydraulic pump can be arbitrarily set according to the current value. In addition, since the giant magnetostrictive element has a high response to expansion and contraction, it is possible to reduce hydraulic pulsation.

  According to the configuration of the sixth aspect, since the giant magnetostrictive element is reciprocally expanded and contracted by controlling the frequency of the current supplied to the coil of the hydraulic pump by the control means, the discharge amount of the hydraulic pump is arbitrarily controlled according to the frequency. In addition, since the giant magnetostrictive element has a high response to expansion and contraction, the pulsation of hydraulic pressure can be reduced. Further, the resonance of the vehicle accompanying the operation of the hydraulic pump can be avoided by setting the current frequency.

  According to the configuration of the seventh aspect, since the hydraulic clutch is provided in each of the left and right auxiliary driving wheels, the main driving wheel and the auxiliary driving wheel can be driven together to be in a four-wheel driving state, and the left and right auxiliary driving wheels can be One of these can be driven to control the yaw moment of the vehicle.

  According to the configuration of the eighth aspect, since the hydraulic oil is supplied to the hydraulic clutch by the first hydraulic pump and the hydraulic oil is sucked from the hydraulic clutch by the second hydraulic pump, the responsiveness when releasing and engaging the hydraulic clutch is greatly increased. Can be increased.

  According to the configuration of the ninth aspect, since the hydraulic oil supplied to the hydraulic clutches of the left and right auxiliary drive wheels is controlled by the three-way valve, there is no need to provide left and right hydraulic pumps corresponding to the left and right hydraulic clutches, respectively. The number of parts can be reduced.

  According to the configuration of the tenth aspect, since the clutch pistons of the left and right hydraulic clutches are arranged so as to sandwich the common oil chamber, the structure of the hydraulic clutch can be simplified and the number of parts can be reduced. The imbalance of the clutch engagement torque can be eliminated.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings.

  1 to 3 show a first embodiment of the present invention. FIG. 1 is a diagram showing a driving force distribution device for a four-wheel drive vehicle. FIG. 2 is a diagram showing the magnitude of current supplied to the hydraulic pump and the generation of the hydraulic pump. FIG. 3 is a graph showing the relationship between the frequency of the current supplied to the hydraulic pump and the hydraulic pressure generated by the hydraulic pump.

  As shown in FIG. 1, the four-wheel drive vehicle V includes left and right front wheels Wf and Wf as main drive wheels and left and right rear wheels Wr and Wr as auxiliary drive wheels. The driving force of the engine E is transmitted to the left and right front wheels Wf, Wf via the transmission M, the final drive gear 11, the final driven gear 12, the front differential gear 13, and the left and right axles 14,14. The driving force of the final driven gear 12 includes a first bevel gear 15, a second bevel gear 16, a front universal joint 17, a propeller shaft 18, a rear universal joint 19, a hydraulic clutch 20, a third bevel gear 21, a fourth bevel gear 22, and a rear differential gear 23. And it is transmitted to the left and right rear wheels Wr, Wr via the left and right axles 24, 24. The hydraulic clutch 20 fastens the propeller shaft 18 to the third bevel gear 21 by driving the clutch piston 26 with the hydraulic pressure acting on the oil chamber 25 to engage the friction engagement members 27.

  The hydraulic pump 30 includes a cylindrical cylinder 31, a pump piston 32 slidably fitted in the cylinder 31, a pump chamber 33 defined between the cylinder 31 and the pump piston 32, and a pump housed in the pump chamber 33. A return spring 34 for urging the piston 32 in the backward direction, a cylindrical super magnetostrictive element 35 connected to the back of the pump piston 32, and a coil 36 disposed on the inner surface of the cylinder 31 so as to surround the super magnetostrictive element 35. With. A discharge port 37 connected to the pump chamber 33 of the cylinder 31 is connected to the oil chamber 25 of the hydraulic clutch 20 via a discharge oil passage 38. A check valve 39 that allows only passage of oil from the hydraulic pump 30 side to the hydraulic clutch 20 side and a first hydraulic sensor 40 that detects oil pressure are disposed in the discharge oil passage 38. A suction port 41 connected to the pump chamber 33 of the cylinder 31 is connected to a reservoir 43 via a suction oil passage 42. A check valve 44 that allows only passage of oil from the reservoir 43 side to the hydraulic pump 30 side and a second hydraulic pressure sensor 45 that detects oil pressure are disposed in the suction oil passage 42. Further, the oil chamber 25 of the hydraulic clutch 20 is connected to the suction oil passage 42 through a discharge oil passage 47 in which an orifice 46 is disposed. The downstream end of the discharge oil passage 47 connected to the suction oil passage 42 is substantially the same as that connected to the reservoir 43, and the discharge oil passage 47 bypasses the second hydraulic sensor 45 and directly enters the reservoir 43. You may connect.

  The giant magnetostrictive element 35 is a Laves-type cubic material composed of a lanthanoid element having a large magnetic moment and an iron group element, and the amount of dimensional change caused by the strength of the magnetic field is smaller than that of other displacement materials. The generated stress, which is a product of the displacement and the strength of the magnetic field, is large. The actuator using the giant magnetostrictive element 35 can exhibit a large output and high responsiveness while being operable at a low voltage.

  The control means 48 composed of a microcomputer includes the oil pressure of the discharge oil passage 38 detected by the first oil pressure sensor 40, the oil pressure of the suction oil passage 42 detected by the second oil pressure sensor 45, and the front wheels Wf detected by the front wheel speed sensor 49. The discharge pressure of the hydraulic pump 30 is controlled by controlling the energization of the coil 36 of the hydraulic pump 30 based on the wheel speed of Wf and the wheel speeds of the rear wheels Wr and Wr detected by the rear wheel speed sensor 50. .

  Next, the operation of the first embodiment having the above configuration will be described.

  After the vehicle V suddenly starts up or the vehicle V suddenly accelerates, the front wheels Wf and Wf, which are the main drive wheels, slip, and the wheel speeds of the front wheels Wf and Wf detected by the front wheel speed sensor 49 are detected by the rear wheel speed sensor 50. When the wheel speeds of the wheels Wr and Wr are exceeded, the coil 36 of the hydraulic pump 30 is energized by a command from the control means 48. When a current is supplied to the coil 36, the giant magnetostrictive element 35 expands and contracts according to the frequency of the current, and when the giant magnetostrictive element 35 extends and the pump piston 32 moves forward, the hydraulic pressure generated in the pump chamber 33 causes the suction port 41 side. When the check valve 44 is closed and the check valve 39 on the discharge port 37 side is opened, oil is supplied to the oil chamber 25 of the hydraulic clutch 20 via the discharge oil passage 38, and the giant magnetostrictive element 35 contracts. When the pump piston 32 moves backward, the check valve 44 on the suction port 41 side is opened by the negative pressure generated in the pump chamber 33 and the check valve 39 on the discharge port 37 side is closed, so that the suction oil Oil in the reservoir 43 is sucked into the pump chamber 33 through the passage 42. At this time, since the oil discharged from the oil chamber 25 of the hydraulic clutch 20 to the discharge oil passage 47 passes through the orifice 46 and is returned to the reservoir 43, the hydraulic pressure rises in the oil chamber 25 of the hydraulic clutch 20, and the clutch piston 26 The hydraulic clutch 20 is engaged by engaging the friction engagement members 27.

  As shown in FIG. 2, when the value of the current supplied to the coil 36 of the hydraulic pump 30 is changed, the amount of expansion and contraction of the giant magnetostrictive element 35 changes according to the current value, That is, the fastening torque of the hydraulic clutch 20 changes. The oil pressure acting on the oil chamber 25 of the hydraulic clutch 20, that is, the oil pressure of the discharge oil passage 38 is monitored by the first oil pressure sensor 40 so that the oil pressure of the oil chamber 25 of the hydraulic clutch 20 becomes a target value, that is, The current value supplied to the coil 36 of the hydraulic pump 30 is feedback-controlled so that the fastening torque of the hydraulic clutch 20 becomes a target value.

  As shown in FIG. 3, when the frequency of the current supplied to the coil 36 of the hydraulic pump 30 is changed, the frequency of the reciprocating motion of the pump piston 32 is changed according to the frequency, and the hydraulic pressure generated by the hydraulic pump 30 is changed. That is, the fastening torque of the hydraulic clutch 20 changes. The frequency of the current supplied to the coil 36 of the hydraulic pump 30 is feedback controlled so that the hydraulic pressure detected by the first hydraulic sensor 40 becomes a target value, that is, the engagement torque of the hydraulic clutch 20 becomes the target value. Is done.

  As described above, since the discharge pressure of the hydraulic pump 30 can be directly controlled by changing the magnitude or frequency of the current supplied to the coil 36 of the hydraulic pump 30, the pressure accumulated in the accumulator can be controlled by a regulator. It is no longer necessary to adjust the pressure and supply it to the hydraulic clutch 20, eliminating the need for an accumulator and a regulator, and reducing the number of parts and the cost. In addition, since the giant magnetostrictive element 35 that is a driving source of the hydraulic pump 30 has extremely high responsiveness on the order of μsec, the hydraulic pump 30 can be operated with a high frequency current of several kHz, and a conventional vane pump or gear pump is used. Compared to the case, the pulsation of the discharge pressure can be reduced, and the generated hydraulic pressure can be controlled with high accuracy. Further, by appropriately setting the frequency of the current, the frequency of the reciprocating motion of the pump piston 32 can be changed, and the resonance of the vehicle accompanying the operation of the hydraulic pump 30 can be easily avoided.

  Furthermore, since the giant magnetostrictive element 35 is used, the voltage applied to the coil 36 is only a few volts, which is much lower than the voltage when the hydraulic pump is driven by an electric motor. And space can be reduced. In addition, since the giant magnetostrictive element 35 and the coil 36, which are the driving source of the hydraulic pump 30, are housed in a compact manner in the hydraulic pump 30, the weight and space are reduced as compared with the case where the hydraulic pump is driven by an electric motor. be able to.

  Furthermore, when an electromagnetic clutch is used, there is a problem that the frictional engagement member is dragged by residual magnetism and the driving force of the engine E is lost, and when the hydraulic pump is driven by the engine E, the driving force of the engine E is directly lost. However, the fuel consumption of the engine E can be reduced by operating the hydraulic clutch 20 by driving the hydraulic pump 30 with the giant magnetostrictive element 35.

  The second hydraulic sensor 45 provided in the suction oil passage 42 is used when the hydraulic pump 30 is frequency-controlled, and the frequency of the current for driving the hydraulic pump 30 becomes too high, so that the reservoir 43 and the suction oil passage are provided. When 42 becomes negative pressure, the frequency of the current is lowered to suppress the generation of negative pressure.

  Next, a second embodiment of the present invention will be described with reference to FIG.

  In the second embodiment, a relief valve 53 is provided in parallel to the orifice 46 of the first embodiment. When the oil pressure in the oil chamber 25 of the hydraulic clutch 20 is excessively increased due to an abnormality in the first oil pressure sensor 40 or the control means 48, rapid release of the oil pressure in the oil chamber 25 is hindered by the flow resistance of the oil passing through the orifice 46. However, when the relief valve 53 is opened, the hydraulic pressure in the oil chamber 25 can be quickly released, and damage to the hydraulic pump 30 and the hydraulic clutch 20 can be prevented.

  Other functions and effects of the second embodiment are the same as those of the first embodiment.

  Next, a third embodiment of the present invention will be described with reference to FIG.

  In the third embodiment, a variable orifice 54 whose opening degree can be controlled by the control means 48 is provided instead of the orifice 46 of the first embodiment. When the opening of the variable orifice 54 is increased, the rise of the hydraulic pressure when oil flows becomes gentle, and when the opening of the variable orifice 54 is decreased, the rise of the hydraulic pressure when oil flows is abrupt. The rise of the fastening torque when the clutch 20 is engaged can be arbitrarily controlled.

  Other functions and effects of the third embodiment are the same as those of the first embodiment.

  Next, a fourth embodiment of the present invention will be described with reference to FIG.

  In the first to third embodiments, the oil chamber 25 of the hydraulic clutch 20 and the reservoir 43 are connected by the discharge oil passage 47, but the fourth embodiment does not have the discharge oil passage 47, Instead, the discharge oil passage 38 and the suction oil passage 42 are connected by the cut valve 55. When the hydraulic pump 30 discharges oil and the hydraulic clutch 20 is engaged, the cut valve 55 is closed by a command from the control means 48 and the communication between the discharge oil passage 38 and the suction oil passage 42 is shut off. . When releasing the engagement of the hydraulic clutch 20, if the cut valve 55 is opened in response to a command from the control means 48, the hydraulic pressure in the oil chamber 25 of the hydraulic clutch 20 passes from the discharge oil passage 38 through the cut valve 55 to the low-pressure intake oil passage. Therefore, the engagement torque of the hydraulic clutch 20 can be released instantaneously.

  Thereby, not only can the response at the time of releasing the engagement of the hydraulic clutch 20 be improved, but also when the oil pressure in the oil chamber 25 of the hydraulic clutch 20 is excessively increased due to the abnormality of the first hydraulic sensor 40 or the control means 48, the cut is performed. By opening the valve 55 and quickly releasing the pressure in the oil chamber 25, damage to the hydraulic pump 30 and the hydraulic clutch 20 can be prevented. Since the braking force of the front wheels Wf and Wf is set to be higher than the braking force of the rear wheels Wr and Wr when the vehicle V is braked, the front wheels Wf and Wf must be fastened and released immediately when braking. May be transmitted to the rear wheels Wr and Wr to disturb the behavior of the vehicle V. However, according to this embodiment, the hydraulic clutch 20 is quickly engaged and released during braking, and the front wheels Wf, Wf and the rear wheels Wr, Wr are disconnected, so that stable braking performance can be obtained.

  Other functions and effects of the fourth embodiment are the same as those of the first embodiment.

  Next, a fifth embodiment of the present invention will be described with reference to FIG.

  In the fifth embodiment, a first hydraulic pump 30 having the same structure and function as the hydraulic pump 30 of the first to fourth embodiments and a second structure having the same structure and different functions as the first hydraulic pump 30 are provided. And a hydraulic pump 30 '. The discharge port 37 of the second hydraulic pump 30 ′ is connected to the reservoir 43 via the discharge oil passage 47, and the suction port 41 is connected to the discharge oil passage 38 via the cut valve 56 connected to the control means 48.

  Thus, when the hydraulic clutch 20 is engaged, the pump piston 32 of the first hydraulic pump 30 is driven, and the oil is supplied from the discharge port 37 to the oil chamber 25 through the check valve 39 and the discharge oil passage 38, whereby the hydraulic clutch 20 is operated. Conclude. At this time, since the cut valve 56 is in the illustrated closed state, the oil discharged from the first hydraulic pump 30 is not supplied to the pump chamber 33 of the second hydraulic pump 30 ′. When the hydraulic pressure supplied to the hydraulic clutch 20 becomes excessive, the relief valve 53 is opened and the hydraulic pressure is released, as in the second embodiment described with reference to FIG.

  When releasing the engagement of the hydraulic clutch 20, the cut valve 56 is opened and the pump piston 32 of the second hydraulic pump 30 'is driven at the same time, so that the oil in the oil chamber 25 of the hydraulic clutch 20 is discharged to the discharge oil passage 38, The air is sucked into the pump chamber 33 of the second hydraulic pump 30 ′ through the cut valve 56, the check valve 44 and the suction port 41, whereby the responsiveness for releasing the engagement of the hydraulic clutch 20 can be dramatically improved.

  Other functions and effects of the fifth embodiment are the same as those of the first embodiment.

  Next, a sixth embodiment of the present invention will be described with reference to FIG.

  The driving force distribution device of the sixth embodiment selectively distributes the driving force to the left and right rear wheels Wr, Wr in addition to equally distributing the driving force to the left and right rear wheels Wr, Wr to increase traction. The aim is to improve turning performance and straight running stability. For this purpose, left and right hydraulic clutches 20L, 20R having the same structure as the hydraulic clutch 20 of the first to fifth embodiments are provided between the fourth bevel gear 22 and the axles 24, 24 of the left and right rear wheels Wr, Wr. Be placed. Corresponding to the left and right hydraulic clutches 20L, 20R, left and right hydraulic pumps 30L, 30R having the same structure as the hydraulic pump 30 of the first to fifth embodiments are arranged. The discharge oil passages 38, 38 connecting the left and right hydraulic pumps 30L, 30R to the left and right hydraulic clutches 20L, 20R are completely independent, and the intake oil passage 42, connecting the reservoir 43 to the left and right hydraulic pumps 30L, 30R, 42 is partly common, and part of the oil discharge passage 47 that connects the left and right hydraulic clutches 20L, 20R to the reservoir 43 is common.

  In addition to the front wheel speed sensor 49 and the rear wheel speed sensor 50, a yaw rate sensor 51 that detects the yaw rate of the vehicle V and a lateral acceleration sensor 52 that detects the lateral acceleration of the vehicle V are connected to the control means 48.

  Thus, when the front wheels Wf and Wf slip when the vehicle V starts suddenly or accelerates, the left and right hydraulic pumps 30L and 30R are simultaneously operated to simultaneously engage the left and right hydraulic clutches 20L and 20R. The state can be realized and the running performance can be improved. Also, the driving force is equally distributed to the left and right rear wheels Wr, Wr to exhibit a so-called differential limiting function, or when one of the left and right rear wheels Wr, Wr slips, the driving force is distributed to the other. By doing so, escape from mud can be facilitated.

  When it is detected that the vehicle V is in a high-speed turning state based on the outputs of the yaw rate sensor 51 and the lateral acceleration sensor 52, only the hydraulic clutches 20L and 20R on the turning outer wheel side are engaged and the driving force is distributed to the turning outer wheel. Thus, the yaw moment that assists turning can be generated to improve turning performance, and conversely, only the hydraulic clutches 20L, 20R on the turning inner ring side are engaged and the driving force is distributed to the turning inner wheel, thereby turning. The stability of the vehicle behavior can be improved by generating a yaw moment that suppresses the vehicle.

  Other functions and effects of the sixth embodiment are the same as those of the first embodiment.

  Next, a seventh embodiment of the present invention will be described with reference to FIG.

  Although the sixth embodiment includes left and right hydraulic pumps 30L and 30R corresponding to the left and right hydraulic clutches 20L and 20R, the seventh embodiment includes only a single hydraulic pump 30. In the sixth embodiment, the oil chambers 25, 25 of the left and right hydraulic clutches 20L, 20R and the reservoir 43 are connected by the discharge oil passage 47, but the seventh embodiment does not include the discharge oil passage 47, Instead, the discharge oil passage 38 and the suction oil passage 42 of the hydraulic pump 30 are connected by a cut valve 57 controlled by the control means 48. Further, a three-way valve 58 controlled by the control means 48 is disposed at a portion where the discharge oil passage 38 of the hydraulic pump 30 is bifurcated toward the left and right hydraulic clutches 20L and 20R.

  Accordingly, when the hydraulic pump 30 is driven when the three-way valve 58 is at the center position shown in the figure, the left and right hydraulic clutches 20L and 20R can be fastened into a four-wheel drive state, and the three-way valve 58 is shown in the center shown in the figure. When operated from the position to the upper position or the lower position, only the left hydraulic clutch 20L or only the right hydraulic clutch 20R is engaged, and the driving force can be distributed to only one of the left and right rear wheels Wr, Wr. Further, when releasing the engagement of the left and right hydraulic clutches 20L, 20R, if the cut valve 57 is opened by a command from the control means 48, the oil pressure in the oil chambers 25, 25 of the left and right hydraulic clutches 20L, 20R is discharged from the discharge oil passage 38. Is released to the low-pressure intake oil passage 42 through the cut valve 57, so that the fastening torque of the left and right hydraulic clutches 20L, 20R can be instantaneously released.

  Thereby, the number of parts can be reduced compared with the case where the left and right hydraulic pumps 30L and 30R are provided corresponding to the left and right hydraulic clutches 20L and 20R, respectively. Moreover, not only can the responsiveness when the left and right hydraulic clutches 20L, 20R are released be released, but also the oil chambers 25, 25 of the left and right hydraulic clutches 20L, 20R can be caused by an abnormality in the first hydraulic sensors 40, 40 and the control means 48. When the hydraulic pressure of the oil pump increases excessively, the cut valve 57 is opened to quickly release the pressure in the oil chambers 25, 25, thereby preventing damage to the hydraulic pump 30 and the left and right hydraulic clutches 20L, 20R. Can do. In addition, since the left and right hydraulic clutches 20L, 20R are quickly engaged and released when the vehicle V is braked, and the front wheels Wf, Wf and the rear wheels Wr, Wr are disconnected, stable braking performance can be obtained.

  Other functions and effects of the seventh embodiment are the same as those of the sixth embodiment.

  Next, an eighth embodiment of the present invention will be described with reference to FIG.

  In the sixth embodiment, the oil chambers 25, 25 of the left and right hydraulic clutches 20L, 20R and the reservoir 43 are connected by the discharge oil passage 47, but the eighth embodiment does not have the discharge oil passage 47, Instead, the discharge oil passages 38, 38 and the suction oil passages 42, 42 of the left and right hydraulic pumps 30L, 30R are connected by cut valves 59, 59. When the left and right hydraulic pumps 30L and 30R discharge oil and the left and right hydraulic clutches 20L and 20R are engaged, the cut valves 59 and 59 are closed by a command from the control means 48, and the discharge oil passages 38 and 38 are closed. In addition, the communication between the suction oil passages 42 and 42 is blocked. When releasing the engagement of the left and right hydraulic clutches 20L, 20R, if the cut valves 59, 59 are opened by a command from the control means 48, the hydraulic pressures in the oil chambers 25, 25 of the left and right hydraulic clutches 20L, 20R are discharged oil passages. Since the valves 38 and 38 are released to the low-pressure intake oil passages 42 and 42 through the cut valves 59 and 59, the fastening torques of the left and right hydraulic clutches 20L and 20R can be instantaneously released.

  Other functions and effects of the eighth embodiment are the same as those of the sixth embodiment.

  Next, a ninth embodiment of the present invention will be described with reference to FIG.

  In the sixth embodiment, the left and right hydraulic clutches 20L and 20R are operated by the corresponding left and right hydraulic pumps 30L and 30R, respectively. In the ninth embodiment, the left and right hydraulic clutches 20L and 20R are simultaneously operated by the common hydraulic pump 30. It is operating. The left and right hydraulic clutches 20L and 20R are integrated, and left and right clutch pistons 26 and 26 are disposed on both sides of an oil chamber 25 common to them. Accordingly, when hydraulic pressure is supplied from the hydraulic pump 30 to the oil chamber 25, the left and right clutch pistons 26, 26 are simultaneously pressed, and the left and right hydraulic clutches 20L, 20R are simultaneously engaged.

  As described above, the left and right hydraulic clutches 20L and 20R share a single oil chamber 25, so that not only the number of parts can be reduced and the structure can be simplified, but also the fastening torque of the left and right hydraulic clutches 20L and 20R can be reduced. It is possible to evenly distribute the driving force to the left and right rear wheels Wr and Wr by preventing the balance.

  Other functions and effects of the ninth embodiment are the same as those of the sixth embodiment, but the fastening torques of the left and right hydraulic clutches 20L and 20R cannot be controlled independently.

  Next, a tenth embodiment of the present invention will be described with reference to FIG.

  The tenth embodiment is a modification of the ninth embodiment, in which the left and right clutch pistons 26, 26 sharing the oil chamber 25 are formed in a bottomed cylindrical shape having different diameters and are slidably fitted to each other. An oil chamber 25 is partitioned inside. As a result, the clutch pistons 26 and 26 can have a cylinder function, and the cylinder can be made unnecessary and the number of parts can be further reduced.

  Other functions and effects of the tenth embodiment are the same as those of the ninth embodiment.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, the hydraulic pumps 30, 30 </ b> L, and 30 </ b> R in the invention of claim 1 are not limited to those using the giant magnetostrictive element 35, and those having an arbitrary structure can be adopted.

  The drive source of the present invention is not limited to the engine E of the embodiment, and may be another drive source such as an electric motor.

  Further, in the embodiment, a vehicle in which the front wheels Wf, Wf are main driving wheels and the rear wheels Wr, Wr are auxiliary driving wheels is illustrated, but the present invention uses the front wheels Wf, Wf as auxiliary driving wheels, and the rear wheels Wr, Wr are The present invention can also be applied to a vehicle that uses main drive wheels.

The figure which shows the driving force distribution apparatus of the four-wheel drive vehicle which concerns on 1st Example. A graph showing the relationship between the magnitude of current supplied to the hydraulic pump and the hydraulic pressure generated by the hydraulic pump Graph showing the relationship between the frequency of the current supplied to the hydraulic pump and the hydraulic pressure generated by the hydraulic pump The figure which shows the driving force distribution apparatus of the four-wheel drive vehicle which concerns on 2nd Example. The figure which shows the driving force distribution apparatus of the four-wheel drive vehicle which concerns on 3rd Example. The figure which shows the driving force distribution apparatus of the four-wheel drive vehicle which concerns on 4th Example. The figure which shows the driving force distribution apparatus of the four-wheel drive vehicle which concerns on 5th Example. The figure which shows the driving force distribution apparatus of the four-wheel drive vehicle which concerns on 6th Example. The figure which shows the driving force distribution apparatus of the four-wheel drive vehicle which concerns on 7th Example. The figure which shows the driving force distribution apparatus of the four-wheel drive vehicle which concerns on 8th Example. The figure which shows the driving force distribution apparatus of the four-wheel drive vehicle which concerns on 9th Example. The figure which shows the driving force distribution apparatus of the four-wheel drive vehicle which concerns on 10th Example.

Explanation of symbols

E Engine (drive source)
V Vehicle Wf Front wheel (main drive wheel)
Wr Rear wheel (sub drive wheel)
20 Hydraulic clutch 20L Hydraulic clutch 20R Hydraulic clutch 25 Oil chamber 26 Clutch piston 30 Hydraulic pump (first oil pump)
30 'second hydraulic pump 30L hydraulic pump 30R hydraulic pump 35 giant magnetostrictive element 36 coil 37 discharge port 38 discharge oil passage 40 first hydraulic sensor (hydraulic sensor)
43 Reservoir 47 Drained oil passage 48 Control means 49 Front wheel speed sensor (running state detection means)
50 Rear wheel speed sensor (running state detection means)
51 Yaw rate sensor (running state detection means)
52 Lateral acceleration sensor (running state detection means)
54 Variable orifice 58 Three-way valve

Claims (10)

Driving a four-wheel drive vehicle capable of distributing a part of the driving force transmitted from the driving source (E) to the main driving wheel (Wf) to the auxiliary driving wheel (Wr) via the hydraulic clutch (20, 20L, 20R). In the power distribution device,
A hydraulic pump (30, 30L, 30R) for generating hydraulic pressure for fastening the hydraulic clutch (20, 20L, 20R);
Traveling state detection means (49-52) for detecting the traveling state of the vehicle (V);
By directly controlling the hydraulic pressure generated by the hydraulic pumps (30, 30L, 30R) based on the traveling state of the vehicle (V) detected by the traveling state detection means (49-52), the main drive wheel (Wf) and the auxiliary drive wheel (Wf) Control means (48) for controlling the distribution of the driving force between the drive wheels (Wr);
A driving force distribution device for a four-wheel drive vehicle.   The driving force distribution device for a four-wheel drive vehicle according to claim 1, wherein the hydraulic pump (30, 30L, 30R) is driven by a giant magnetostrictive element (35). Hydraulic sensor (40) for detecting the hydraulic pressure of the discharge oil passage (38) connecting the discharge port (37) of the hydraulic pump (30, 30L, 30R) and the oil chamber (25) of the hydraulic clutch (20, 20L, 20R). )
The control means (48) controls the operation of the hydraulic pump (30, 30L, 30R) so that the hydraulic pressure detected by the hydraulic sensor (40) matches the target hydraulic pressure. A drive force distribution device for a four-wheel drive vehicle according to claim 1.   The variable orifice (54) is provided in the discharge oil passage (47) connecting the oil chamber (25) and the reservoir (43) of the hydraulic clutch (20, 20L, 20R), according to claim 3. Drive power distribution device for four-wheel drive vehicles. The hydraulic pump (30, 30L, 30R) includes a coil (36) that generates a magnetic field for expanding and contracting the giant magnetostrictive element (35).
The driving force distribution device for a four-wheel drive vehicle according to claim 2, wherein the control means (48) controls the magnitude of the current supplied to the coil (36). The hydraulic pump (30, 30L, 30R) includes a coil (36) that generates a magnetic field for expanding and contracting the giant magnetostrictive element (35).
The driving force distribution device for a four-wheel drive vehicle according to claim 2, wherein the control means (48) controls the frequency of the current supplied to the coil (36).   The driving force distribution of a four-wheel drive vehicle according to any one of claims 1 to 6, wherein a hydraulic clutch (20L, 20R) is provided on each of the left and right auxiliary drive wheels (Wr). apparatus.   A first hydraulic pump (30) for supplying hydraulic oil to the hydraulic clutch (20) and a second hydraulic pump (30 ') for sucking hydraulic oil from the hydraulic clutch (20) are provided. Item 4. A driving force distribution device for a four-wheel drive vehicle according to Item 1.   The four-wheel drive according to claim 7, wherein hydraulic oil (20L, 20R) provided to the left and right auxiliary drive wheels (Wr) is controlled by a three-way valve (58). Vehicle driving force distribution device. The hydraulic clutches (20L, 20R) provided on the left and right auxiliary drive wheels (Wr) are respectively fastened by the left and right clutch pistons (26) arranged so as to sandwich the common oil chamber (25). The driving force distribution device for a four-wheel drive vehicle according to claim 7, characterized in that it is characterized in that:

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