JP2005280708A - Power transmitting device of four-wheel-drive vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmitting device for a four-wheel-drive vehicle structured without a large scale piping to connect a hydraulic pump with a hydraulic clutch and/or any particular electric motor for driving the hydraulic pump, capable of engaging the hydraulic clutch by generating a hydraulic force quickly at the time of starting. <P>SOLUTION: The driving force from an engine E and a transmission M is transmitted to the front wheels W<SB>FL</SB>and W<SB>FR</SB>through a first power transmitting line D<SB>1</SB>and also to the rear wheels W<SB>RL</SB>and W<SB>RR</SB>through a second power transmitting line D<SB>2</SB>. On a propeller shaft S installed in the second power transmitting line D<SB>2</SB>, the hydraulic pump P is installed upstream in the power transmitting direction, while the hydraulic clutch C is installed in the downstream. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention includes a first power transmission system that transmits driving force of an engine to first driving wheels, a second power transmission system that transmits driving force of the first power transmission system to second driving wheels, and a second power transmission. The present invention relates to a power transmission device for a four-wheel drive vehicle that includes a hydraulic clutch that is interposed in the system and controls transmission of driving force to a second driving wheel, and a hydraulic pump that supplies hydraulic oil to the hydraulic clutch.

  Such power transmission devices for four-wheel drive vehicles are already known from Japanese Patent Application Laid-Open Nos. 2-286429 and 7-17426.

  By the way, what is described in the above-mentioned Japanese Patent Application Laid-Open No. 2-286429 is that when the hydraulic pump is directly driven by the crankshaft of the engine, the distance between the hydraulic pump and the hydraulic clutch becomes large and the piping is long. Therefore, there is a problem that the layout of the piping is hindered. Further, when the hydraulic pump is driven by an electric motor, a special electric motor for the hydraulic pump is required, which increases the cost.

  Further, in the device described in Japanese Patent Laid-Open No. 7-17426, the hydraulic pump is driven by one wheel of the second drive wheel, so that a hydraulic clutch is interposed between the engine and the hydraulic pump. . Therefore, even if the hydraulic clutch is engaged to make the four-wheel drive state when the vehicle starts, the driving force of the engine is transmitted from the first power transmission system to the first drive wheel, and the vehicle starts running. As a result, after the second driving wheel is rotated by the frictional force from the road surface and the hydraulic pump is operated, the hydraulic clutch is engaged for the first time, and the engine driving force is transmitted from the second power transmission system to the second driving wheel. It will be in a wheel drive state. Accordingly, there is a problem that the four-wheel drive state cannot be promptly realized when the vehicle starts, and the start performance is deteriorated.

  The present invention has been made in view of the above-described circumstances, and does not require a long pipe for connecting the hydraulic pump and the hydraulic clutch or a special electric motor for driving the hydraulic pump, and promptly generates hydraulic pressure when starting. Another object is to provide a power transmission device for a four-wheel drive vehicle capable of engaging a hydraulic clutch.

  In order to achieve the above object, the invention described in claim 1 is directed to a first power transmission system for transmitting the driving force of the engine to the first driving wheel, and the driving force of the first power transmission system to the second driving wheel. A second power transmission system that transmits power to the hydraulic power source, a hydraulic clutch that is interposed in the second power transmission system and controls transmission of driving force to the second drive wheel, and a hydraulic pump that supplies hydraulic oil to the hydraulic clutch In the power transmission device for a four-wheel drive vehicle, the hydraulic pump is disposed closer to the engine than the hydraulic clutch of the second power transmission system, and is driven by the driving force of the second power transmission system.

  According to a second aspect of the present invention, in addition to the configuration of the first aspect, the second power transmission system includes a propeller shaft extending in the longitudinal direction of the vehicle body, and the hydraulic pump is driven by the propeller shaft. It is characterized by.

  According to a third aspect of the present invention, in addition to the configuration of the first aspect, the second power transmission system includes a pair of left and right hydraulic clutches that control transmission of driving force to the pair of left and right second drive wheels. It is characterized by that.

  As described above, according to the first aspect of the present invention, the hydraulic pump is disposed closer to the engine than the hydraulic clutch of the second power transmission system, and is driven by the driving force of the second power transmission system. In addition to the necessity of a special drive source such as an electric motor for driving the hydraulic pump, the length of the pipe can be shortened by arranging the hydraulic pump and the hydraulic clutch in the same second power transmission system. Moreover, even when the hydraulic clutch is in the disengaged state, the driving force of the engine is transmitted to the hydraulic pump without passing through the hydraulic clutch, so that the hydraulic pump can be operated quickly when the vehicle starts. As a result, the four-wheel drive state can be realized by engaging the hydraulic clutch simultaneously with the start of the vehicle, and the start performance can be improved.

  According to the second aspect of the present invention, the second power transmission system includes the propeller shaft extending in the longitudinal direction of the vehicle body, and the hydraulic pump is driven by the propeller shaft, so that the hydraulic pressure is set at an arbitrary position of the propeller shaft. A pump can be arranged to improve space efficiency and design flexibility.

  According to the invention described in claim 3, since the second power transmission system includes the pair of left and right hydraulic clutches for controlling the transmission of the driving force to the pair of left and right second drive wheels, the pair of left and right second clutches It is possible to improve the turning performance and the straight running stability by arbitrarily controlling the distribution of the driving force to the driving wheels.

  Hereinafter, embodiments of the present invention will be described based on examples of the present invention shown in the accompanying drawings.

  1 and 2 show a first embodiment of the present invention. FIG. 1 is a skeleton diagram of a power transmission device for a four-wheel drive vehicle, and FIG. 2 is a hydraulic circuit diagram.

As shown in FIG. 1, the four-wheel drive vehicle V includes an engine E disposed horizontally in the front of the vehicle body and a transmission M coupled to the right side surface of the engine E. The first power transmission system D ₁ that transmits the driving force of the transmission M to the left and right front wheels W _FL , W _FR is engaged with the first spur gear 2 provided on the output shaft 1 of the transmission M and the second spur gear 2. A spur gear 3, a bevel gear type front differential 4 driven by the second spur gear 3, and left and right axles 5, 5 extending from the front differential 4 to the left and right and connected to the front wheels W _FL , W _FR. .

The second power transmission system D ₂ that transmits the driving force of the first power transmission system to the rear wheels W _RL and W _RR meshes with the third spar gear 6 and the third spar gear 6 provided in the differential box of the front differential 4. A fourth spur gear 7, a first bevel gear 8 that rotates integrally with the fourth spur gear 7, a second bevel gear 9 that meshes with the first bevel gear 8, and a propeller shaft S that includes the second bevel gear 9 at the front end and extends rearward of the vehicle body. A third bevel gear 10 provided at the rear end of the propeller shaft S, a fourth bevel gear 11 meshing with the third bevel gear 10, a rear differential 12 driven by the fourth bevel gear 11, and left and right from the rear differential 12. And left and right axles 13 and 13 connected to the rear wheels W _RL and W _RR .

Further, the second power transmission system D ₂ includes a hydraulic pump P and a hydraulic clutch C that are interposed in series in the middle portion of the propeller shaft S, and the hydraulic pump P is upstream of the power transmission direction (front differential 4). The hydraulic clutch C is arranged on the downstream side (rear differential 12 side) in the power transmission direction. The hydraulic clutch C is connected to a hydraulic pump P through a hydraulic circuit described later, and is engaged by hydraulic oil discharged from the hydraulic pump P.

As shown in FIG. 2, the hydraulic pump P that pumps hydraulic oil from the oil tank 21 through the oil passage L ₁ operates when the rotation direction of the propeller shaft S is reversed as the vehicle V moves forward and backward. The discharge direction is reversed. Accordingly, in order to supply hydraulic oil to the hydraulic clutch C regardless of the rotation direction of the propeller shaft S, the two check valves 22 and 22 are mounted between the intake side oil passage L ₁ and the discharge thereof. two check valves 23, 23 are mounted between the oil passage L ₂ side.

The oil passage L ₂ connected to the downstream side of the hydraulic pump P is connected to the accumulator A through a check valve 24. Oil passage L ₃ connecting to the downstream side of the accumulator A is connected to the linear solenoid valve 26 via a check valve 25, the oil passage L ₄ further connected to the downstream of the linear solenoid valve 26 is connected to the hydraulic oil chamber 27 of the hydraulic clutch C Is done. Excess hydraulic oil discharged from the linear solenoid valve 26 returns to the oil passage L ₁ upstream of the hydraulic pump P via the oil passage L ₅ .

From the oil passage L ₄ between the linear solenoid valve 26 and the hydraulic clutch C of the working oil chamber 27 is an oil passage L ₆ which is interposed a pressure sensor 28 and a relief valve 29 in series is branched, the oil passage L ₆ The downstream side branches into an oil passage L ₇ and an oil passage L ₈ . One oil passage L ₇ communicates between the friction plates 30 of the hydraulic clutch C and communicates with the oil tank 21 via the other oil passage L ₈ relief valve 31.

Thus, after the hydraulic oil discharged from the hydraulic pump P is accumulated in the accumulator A, it is regulated by the linear solenoid valve 26 and supplied to the hydraulic oil chamber 27 of the hydraulic clutch C, and the rear wheels W _RL , W _RR. The hydraulic clutch C is engaged with a predetermined engaging force so as to transmit the driving force. At this time, the opening degree of the linear solenoid valve 26 is feedback controlled based on the pressure of the hydraulic oil chamber 27 detected by the pressure sensor 28. The hydraulic oil that has been relieved from the relief valve 29 is blocked by the relief valve 31 to become lubricating oil of a predetermined pressure, and lubricates the friction plates 30 of the hydraulic clutch C.

When the hydraulic clutch C is disengaged by controlling the linear solenoid valve 26 as described above, the driving force of the engine E is transmitted only to the front wheels W _FL and W _FR to enter the front wheel driving state, and the hydraulic clutch C Is engaged, the driving force of the engine E is transmitted to both the front wheels W _FL and W _FR and the rear wheels W _RL and W _RR so that the four-wheel drive state is achieved. By changing the engagement force of the hydraulic clutch C, the distribution ratio of the driving force between the front wheels W _FL and W _FR and the rear wheels W _RL and W _RR can be changed.

  When starting the vehicle V, the hydraulic clutch C is engaged to improve the starting performance so as to be in a four-wheel drive state. However, since the hydraulic pump P is disposed upstream of the hydraulic clutch C in the power transmission direction, the transmission M Can output the driving force to rotate the propeller shaft S and simultaneously operate the hydraulic pump P to quickly engage the hydraulic clutch C. As a result, when the vehicle V starts, the four-wheel drive state can be quickly set to improve the starting performance.

  Further, since the hydraulic pump P is driven by the driving force of the engine E, a special drive source such as an electric motor is not necessary, which can contribute to cost reduction. In addition, since the hydraulic pump P and the hydraulic clutch C can be disposed close to each other, the length of the pipe can be shortened compared to the case where the hydraulic pump P is driven by the crankshaft of the engine E, and The degree of freedom in design can be increased by arranging the hydraulic pump P at an arbitrary position along the propeller shaft S that is long in the longitudinal direction of the vehicle body.

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

The second embodiment is abolished rear differential 12 in the first embodiment, and respectively left hydraulic clutch on the axle 13 of the left and right instead of the clutch C that is interposed in the propeller shaft S C _L and the right hydraulic clutch C _R Is provided.

This second embodiment also, the hydraulic clutch C _L, by a C _R to disengage or engage can switch the four-wheel drive state and the front wheel drive state, moreover the hydraulic clutch C _L, the engagement force of the C _R By changing the driving force distribution ratio among the front wheels W _FL and W _FR and the rear wheels W _RL and W _RR .

Further, since the hydraulic pump P is disposed on the propeller shaft S on the upstream side in the power transmission direction with respect to the hydraulic clutches C _L and C _R , as in the first embodiment, the vehicle V is quickly put into a four-wheel drive state and started. Performance can be improved. Furthermore, it is possible to obtain the same effects as those of the first embodiment in that a special drive source such as an electric motor is not required and the length of the pipe can be shortened.

Figure 5 shows a third embodiment of the present invention, the third embodiment of the engagement of the left clutch C _L and the right clutch C _R, the corresponding linear solenoid valve 26 _L, 26 _R by separately Can be controlled.

According to the third embodiment, in addition to the operational effects of the second embodiment, the distribution ratio of the driving force distributed to the left and right rear wheels W _RL , W _RR is changed to improve the turning performance and the straight running stability. It is possible to improve the performance.

  As mentioned above, although the Example of this invention was explained in full detail, this invention can perform a various design change in the range which does not deviate from the summary.

Skeleton diagram of power transmission device for four-wheel drive vehicle Hydraulic circuit diagram of power transmission device The figure corresponding to the said FIG. 1 based on 2nd Example. The figure corresponding to the said FIG. 2 based on 2nd Example. The figure corresponding to the said FIG. 2 based on 3rd Example.

Explanation of symbols

C Hydraulic clutch C _L Left hydraulic clutch (Hydraulic clutch)
_CR Right hydraulic clutch (hydraulic clutch)
D ₁ 1st power transmission system D ₂ 2nd power transmission system E Engine P Hydraulic pump S Propeller shaft W _FL , W _FR Front wheel (first drive wheel)
W _RL , W _RR rear wheel (second drive wheel)

Claims (3)

A first power transmission system (D ₁ ) for transmitting the driving force of the engine (E) to the first drive wheels (W _FL , W _FR );
The second power transmission system for transmitting first power transmission system for driving force (D ₁₎ second drive wheels (W _RL, W _RR) in the (D _2),
Hydraulic clutches (C, C _L , C _R ) interposed in the second power transmission system (D ₂ ) to control the transmission of driving force to the second drive wheels (W _RL , W _RR );
A hydraulic pump (P) for supplying hydraulic oil to the hydraulic clutches (C, C _L , C _R );
In a power transmission device for a four-wheel drive vehicle comprising:
The hydraulic pump (P) is interposed in the hydraulic clutch _{(C, C L, C R} ) engine (E) side of the second power transmission system (D _2), the second power transmission system (D ₂₎ A power transmission device for a four-wheel drive vehicle, characterized by being driven by a driving force of The second power transmission system (D ₂ ) includes a propeller shaft (S) extending in the longitudinal direction of the vehicle body, and the hydraulic pump (P) is driven by the propeller shaft (S). 4. A power transmission device for a four-wheel drive vehicle according to 1. The second power transmission system (D ₂ ) includes a pair of left and right hydraulic clutches (C _L , C _R ) for controlling transmission of driving force to the pair of left and right second drive wheels (W _RL , W _RR ). The power transmission device for a four-wheel drive vehicle according to claim 1, wherein the power transmission device is a four-wheel drive vehicle.

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