JP3659696B2 - Transfer device for four-wheel drive vehicle - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a transfer structure, and more particularly to a transfer structure provided with a hydraulic fluid system including a transfer speed change element and a communication passage that supplies hydraulic fluid from a hydraulic power source to a hydraulic actuator that operates the element.
[0002]
[Prior art]
Conventionally, vehicle rotation transmission systems have been equipped with transmissions and transfers, and these transmissions and transfers are often equipped with planetary gear trains. The low speed mode is switched.
For example, in the case of transfer, the output rotation from the automatic transmission A / T (not shown) is changed to the first output shaft (rear wheel) by changing the output rotation that is shifted and branched through the high / low switching mechanism and the switching mechanism of two-wheel drive and four-wheel drive. Side) and the second output shaft (front wheel side).
[0003]
Here, the high / low switching mechanism can switch the shifting element in the high speed mode, switch the planetary gear train to the direct connection state and transmit the rotation to the output shaft, and switch the planetary gear train to the deceleration state and transmit the rotation to the output shaft in the low speed mode. it can.
[0004]
On the other hand, the switching mechanism between the two-wheel drive and the four-wheel drive switches the shift element, and transmits the rotation only to the rear wheel side during the two-wheel drive, and transmits the rotation to the front and rear four wheels during the four-wheel drive.
[0005]
[Problems to be solved by the invention]
However, this type of transfer requires that the oil pressure level applied to each shifting element is accurately switched between high and low, and switching must be made reliably by the oil pressure, but may malfunction due to deterioration over time. . In this way, if each shifting element malfunctions, there is a possibility that the driving force is not transmitted, or that the gears having different gear ratios engage and operate at the same time. Yes.
An object of the present invention is to provide a transfer structure capable of avoiding a driving force transmission abnormality due to a malfunction of a hydraulic circuit connected to a speed change element and a driving system interlock state.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 distributes the driving force from the driving force source to the front wheel side output unit and the rear wheel side output unit, and the front wheel side output unit and the rear wheel side output unit. Differential withAllowIn a transfer device for a four-wheel drive vehicle having a center differential, the center differential is connected to the drive source.And input the above driving forceA first element, a second element that transmits the driving force to the front wheel side output unit, a third element that transmits the driving force to the rear wheel side output unit, and a fourth element that can be fixed to a fixing member, The transfer device further includes a hydraulic first that enables engagement / release of the front wheel output unit and the second element.clutchAnd a hydraulic second that enables engagement / release of the front wheel side output portion and the third element.clutchAnd a hydraulic type capable of engaging / releasing the fourth element with respect to the fixing memberbrakeWhen the hydraulic pressure is not supplied, the hydraulic firstclutchBiasing means for engaging the hydraulic secondclutchWhen the hydraulic pressure is supplied, the front wheel side output portion and the third element are engaged, and when the hydraulic pressure is supplied, the hydraulic brake sets the fourth element to a fixed state, and the hydraulic second 1clutchIs characterized in that when the hydraulic pressure is not supplied, the urging means brings the front wheel side output portion and the second element into an engaged state.
[0007]
In the invention of claim 2, the driving force from the driving force source is obtained.A first element for input; a second element for transmitting the driving force to the front wheel side output unit; and a third element for transmitting the driving force to the rear wheel side output unit.Front wheel side output sectionthe aboveA center differential that distributes to the rear wheel side output section, and the center differentialthe aboveFirst2Disposed between the element and the front wheel side output section,2Hydraulic type that keeps the element and the front wheel side output section disconnectedclutchWhen,The rotational force output from the center differential can be cut between the high speed stage and the low speed stage according to the supplied hydraulic pressure, and the supplied hydraulic pressure ishydraulicclutchHas the same hydraulic supply pattern asHydraulic brakeAnd the above hydraulic typeclutchFirst hydraulic supply oil passage to the above-mentioned hydraulic typebrake3rd hydraulic supply oil passage to the two oil passagesInA valve device arranged in common, the valve device is the hydraulic typeclutchSupply hydraulic pressure and hydraulic type abovebrakeOnly when the deviation of the hydraulic pressure supplied to theThe hydraulic clutch and the hydraulic brakeIt was characterized by shutting off the hydraulic pressure supply to.
[0008]
The invention of claim 3 is the transfer device for a four-wheel drive vehicle according to claim 2, wherein the valve device isDeviation between the hydraulic pressure supplied to the hydraulic clutch and the hydraulic pressure supplied to the hydraulic brake isA neutral spring capable of restricting the switching operation of the valve device within a predetermined value is mounted.
[0009]
According to a fourth aspect of the present invention, in the transfer device for a four-wheel drive vehicle according to the second aspect, the hydraulic typeclutchThe first shifting element is joined by a spring force, and when the first hydraulic actuator receives the hydraulic pressure, the spring force is released and the clutch disengaged state is maintained.
[0010]
[Action]
The first invention distributes the driving force from the driving force source to the front wheel side output unit and the rear wheel side output unit by the center differential, and is a hydraulic type that is interposed in the front wheel side output unit by the hydraulic pressure from the hydraulic source. 1clutchAnd a hydraulic second interposed between the front wheel side output section and the rear wheel side.clutchCan be selectively engaged, especially when hydraulic pressure is not applied.clutchIs provided in the engaging direction, so that at least the hydraulic firstclutchThe front wheel side output portion and the second element are joined by the urging force of the urging means, and the hydraulic firstclutchWhen the hydraulic pressure is received, the urging force is released and the clutch disengaged state is maintained, so that the switching operation can be performed reliably when the hydraulic pressure is switched.
[0011]
According to a second aspect of the present invention, there is provided a center differential for distributing the driving force from the driving force source to the front wheel side output unit and the rear wheel side output unit,2Disposed between the element and the front wheel side output section,2Hydraulic type that keeps the element and the front wheel side output section disconnectedclutchAnd the same hydraulicclutchWith the same hydraulic supply pattern asbrakeAnd the above hydraulic typeclutchFirst hydraulic supply oil passage to the above-mentioned hydraulic typebrakeA third hydraulic pressure supply oil passage and a valve device arranged in common to both the oil passages, and the valve device is the hydraulic typeclutchSupply oil path to the above hydraulic typebrakeSince the hydraulic pressure supply to both friction elements is cut off only when the deviation of the supplied hydraulic pressure exceeds the predetermined value, only when the deviation of the hydraulic pressure of the first and third hydraulic supply oil paths is below the predetermined value. HydraulicclutchAnd hydraulicbrakeIs operated normally, and the shift operation is performed. When the deviation is large, both the first hydraulic supply oil passage and the third hydraulic supply oil passage are shut off and hydraulically operated.clutchAnd hydraulicbrakeIs switched off to prevent a malfunction.
[0012]
According to a third aspect of the present invention, there is provided the transfer device for a four-wheel drive vehicle according to the second aspect, wherein the valve device is in particular.Deviation between the hydraulic pressure supplied to the hydraulic clutch and the hydraulic pressure supplied to the hydraulic brakeSince the neutral spring that can regulate the switching operation of the valve device within the predetermined value is mounted, the dead zone can be set easily.
[0013]
According to a fourth aspect of the present invention, there is provided a transfer device for a four-wheel drive vehicle according to the second aspect of the present invention.clutchThe first shifting element is joined by a spring force, and when the first hydraulic actuator receives the hydraulic pressure, the spring force is released and the clutch disengaged state is maintained, so that the gear shifting operation can be reliably performed when the hydraulic pressure is switched. .
[0014]
【Example】
Of FIG.The transfer device for a four-wheel drive vehicleIt is mounted on a transfer 11 in a power transmission system of a four-wheel drive vehicle.
This power transmission system is connected to an engine 12 as a drive source, an automatic transmission A / T and a transfer 11 sequentially connected in series thereafter, and a first output shaft 13 of the transfer 11 via a not-shown peller shaft or a rear differential. And rear wheels.
Here, the automatic transmission A / T includes a torque converter (hereinafter simply “torque converter”) 14 and a transmission 15. The torque converter 14 converts the rotation of the crankshaft 17 into oil kinetic energy by the pump impeller 16 and performs a process in which the turbine impeller 18 converts the oil kinetic energy into rotation of the turbine rotation shaft 19 again. A well-known configuration is adopted in which the stator 20 between the vehicles adjusts the conversion efficiency at that time. The transmission 15 shifts the input rotation of the turbine rotation shaft 19 to a plurality of stages using a planetary gear train 21 and a shift element including a hydraulic actuator (not shown), and the first rotation member of the transfer 11 directly connected to the output shaft 22.26The speed-changed rotation is output.
Reference numeral 24 denotes a gear pump. The pump 24 is integrally connected to the crankshaft 17 via a pump impeller 16 in the torque converter 14, and the hydraulic pressure of the hydraulic circuit of the automatic transmission A / T and the transfer 11 when the pump is operated. Work as a source.
[0015]
The transfer 11 has a high / low switching mechanism (indicating a center differential function) 111 andCenter differential lock mechanism (hereinafter simply referred to as the lock mechanism)The output rotation shifted and branched via 112 is transmitted to the second output shaft 25 via the first output shaft 13 and the belt V.
As shown in FIGS. 1 and 6, the transfer 11 has a first rotating member 26 integral with the output shaft 22, a first output shaft 13 connected to the rear wheel 27, and a front portion of the first output shaft 13. The intermediate output shaft 28 to be fitted, the second rotating member 29 to be fitted to the rear portion of the first output shaft 13, the front carrier 30 integrally coupled to the front portion of the first output shaft 13, and the first output shaft 13 and a third rotating member 31 integrally coupled to the rear portion.
[0016]
Further, a fourth rotating member 32 is fitted on the rear end of the intermediate output shaft 28, and a cylindrical shaft 33 is fitted on the front portion of the intermediate output shaft 28.
The cylindrical shaft 33 includes a second sun gear 34 at a front end thereof, and a rear end thereof is supported by the casing 35 via the first brake B1 so as to be able to contact and separate. The intermediate output shaft 28 includes a first sun gear 36 at the front end thereof, and the rear end thereof is supported by the second rotation member 29 via the fourth rotation member 32 and the first clutch C1 so as to be able to contact and separate.
The first brake B1, which constitutes the main part of the high / low switching mechanism 111, enters the brake operation by joining the sliding contact element when the hydraulic chamber 45, which forms the main part of the hydraulic actuator, is at a high hydraulic pressure level (when the hydraulic pressure is on). The sun gear 34 is fixed. On the contrary, when the hydraulic chamber 45 is at a low hydraulic pressure level (when the hydraulic pressure is off), the slidable contact element is released and the brake is inactivated, causing the second sun gear 34 to idle.
[0017]
Inner peripheral teeth 37 are formed on the front carrier 30, and a first pinion gear 38 pivotally supported by the first rotating member 26 meshes with the inner peripheral teeth 37. The first pinion gear 38 meshes with the first sun gear 36 inside thereof, and also meshes with the second sun gear 34 via the second pinion gear 39.
The first output shaft 13 connected to the rear wheel 27 is provided with first and second central oil passages 40 and 41 in parallel. The first central oil passage 40 receives hydraulic pressure from an oil supply passage (not shown) communicating with one end side in FIG. 1, and oil is dispersed and discharged from a plurality of discharge ports 401 to be used for lubricating each sliding member.
[0018]
The second central oil passage 41 has a control oil pressure for turning on a second clutch C2 described later, a first oil passage 411 formed in a part of the casing 35, an annular passage 412, and an inflow passage 413 of the intermediate output shaft 28. And the control hydraulic pressure supplied to the hydraulic chamber 42 forming the hydraulic actuator of the second clutch C2 via the communication port 415 of the second rotating member 29 communicated with one end of the second central oil passage 41. The structure of supplying is adopted.
[0019]
The second rotating member 29 has a first clutch C1 that forms a main part of the high / low switching mechanism 111 at a front portion thereof.LockA second clutch C2 that constitutes a main part of the mechanism 112 is provided in parallel, and a front wheel side output gear 431 connected to the belt V is integrally coupled to the rear end thereof.
Here, the first clutch C1 is always an on-clutch. That is, a plate-like pressing spring 43 is provided at the end of the sliding contact element row, and the sliding contact element is moved by the elastic force of the spring 43 when the hydraulic chamber 44, which is a main part of the hydraulic actuator, is at a low hydraulic pressure level (when the hydraulic pressure is off). The first sun gear 36 is directly connected to the second rotating member 29. On the contrary, when the hydraulic chamber 44 is turned on (when hydraulic pressure is supplied), the elastic force of the pressing spring 43 is released from the sliding contact element, and the first sun gear 36 is rotated freely.
[0020]
On the other hand, the second clutch C2 isCenter differential lockThis is a clutch, and when the hydraulic chamber 42 is turned on (when hydraulic pressure is supplied), the sliding contact element is joined, and the first output shaft 13 and the second rotating member 29 are joined.Center differential lockMode, and when the hydraulic chamber 42 is at a low hydraulic pressure level (when the hydraulic pressure is off), the joining of the sliding contact element is released, and the first output shaft 13 and the second rotating member 29 are separated,Center differential freeMode.
Here, the first brake B1, the first clutch C1, and the second clutch C2 are connected to the hydraulic circuit shown in FIG.
As shown in FIG. 3, the main oil passage 46 of the transfer 11 includes electromagnetic valves 47, 48, 49 and a metering valve 50 provided in association with the hydraulic chambers 45, 44, 42 of the respective elements B1, C1, C2. , 51, 52.
Each solenoid valve 47, 48, 49 communicates the supply port a and the drain port b when off, and communicates the supply port a and the inflow port c when on. The supply port a of the solenoid valves 47, 48 and 49 is communicated with the pilot port d of the metering valves 50, 51 and 52. The electromagnetic valve 47 as the first electromagnetic valve supplies pilot pressure to the pressure regulating valve 50. A solenoid valve 48 as a second solenoid valve supplies pilot pressure to the pressure regulating valve 51. The electromagnetic valve 49 supplies pilot pressure to the pressure regulating valve 52. Here, the first and third hydraulic pressures of the metering valves 50, 51, 52 are increased / decreased by the pilot pressures of the electromagnetic valves 47, 48, 49.
[0021]
The metering valves 50, 51, and 52 include a pilot port d, an inflow port e that receives a line pressure, a supply port f, and a plurality of drain ports g. The metering valves 50, 51, 52 slide the spool valve 54 by the balance between the elastic force of the spring 53 and the hydraulic pressure of the pilot port d, and the amount of oil from the inflow port e toward the supply port f and the drain port from the supply port f. Adjust the amount of oil going to g.
The supply ports f of the metering valves 50 and 51 communicate with the first clutch C1 and the first brake B1 via the fail safe valve 55.
The fail-safe valve 55 includes inflow ports h1 and h2 that communicate with the supply ports f of the metering valves 50 and 51, and supply ports i1 and i2 that face the first and second brakes B1 and C1, respectively. Further, a plurality of drain ports j are provided.
[0022]
Here, the metering valve 50 as the first pressure regulating valve communicates with the supply port f, the inflow port h1, the supply port i1, the hydraulic chamber 45 of the first brake B1, and the first oil passage R1 that sequentially follows the first oil passage R1. The first hydraulic pressure is supplied from the metering valve 50. Similarly, the metering valve 51 as the second pressure regulating valve communicates with the second oil path R2 that continues to the supply port f, the inflow port h2, the supply port i2, the hydraulic chamber 44 of the first clutch C1, and the second oil path R2. The second hydraulic pressure is supplied from the metering valve 51. Similarly, the metering valve 52 as the third pressure regulating valve communicates with the supply port f, the hydraulic chamber 42 of the second clutch C2 and the third oil passage R3, and the third oil passage R3 has a third hydraulic pressure from the metering valve 52. Is supplied.
[0023]
In addition, the code | symbol 60 in FIG. 3 shows an accumulator.
The fail safe valve 55 includes a spool 56, and pressure receiving portions 561 and 562 (having the same pressure receiving area Af) facing the first and second oil passages R1 and R2 are formed in the spool 56, and the first and second oils are formed. The paths are formed so that they can be connected and disconnected at the same time. In particular, a neutral spring 57 is attached to one end of the spool 56.
[0024]
An extension portion 563 is formed at one end of the spool 56, a pair of projections 564 are formed at a predetermined interval on the extension portion 563, and a neutral spring 57 is interposed between the pair of projections 564 via a pair of spring receivers 565. Installed. The neutral spring 57 applies a set load Fo to the spool 56, and when the spool 56 receives an oil pressure exceeding the set load Fo, the neutral spring 57 is compressed and displaced in either the left or right direction. .
[0025]
Here, the spool 56 is configured to receive the first hydraulic pressure p1 and the second hydraulic pressure p2 of the first and second oil passages R1 and R2 by the left and right pressure receiving portions 561 and 562 in a direction opposite to each other. Here, the spool 56 is pressed to one side by the load obtained by multiplying the deviation Δp between the first hydraulic pressure p1 and the second hydraulic pressure p2 received by the left and right pressure receiving portions 561 and 562 by the pressure receiving area Af, and the same value exceeds the set load Fo (Δp × Af > Fo) and the neutral spring 57 can be elastically displaced to simultaneously block the first oil path R1 and the second oil path R2, and in the dead zone that does not exceed the set load Fo, the first oil path R1 and the second oil path R2 is opened.
[0026]
Thus, even if the first hydraulic pressure p1 and the second hydraulic pressure p2 are relatively shifted within the deviation Δp due to the attachment of the neutral spring 57, the spool 56 does not block the first and second oil passages, and this dead zone. By setting this, it is possible to restrict unnecessary oil passage blocking operation due to a relative responsiveness difference between the first hydraulic pressure p1 and the second hydraulic pressure p2 when the hydraulic pressure is switched.
[0027]
The operation of such a transfer structure will be described.
The pump 24 is driven in conjunction with the engine 12, and the line pressure of the pump 24 is supplied through the main oil passage 46.
Here, when the vehicle is traveling, the driving force is shifted at an appropriate gear ratio by the automatic transmission A / T and transmitted to the first rotating member 26 of the transfer 11.
[0028]
high speed4 wheel driveWhen the mode is selected, as shown in FIG. 4B, the solenoid valve 47 is deenergized, the first oil passage R1 is shut off by the metering valve 50, and the hydraulic pressure is supplied to the first brake B1. Break. Further, when the solenoid valve 48 is deenergized, the second oil passage R2 is shut off by the metering valve 51, and the first clutch C1 is held in contact with the elastic force of the spring 43. In this case, the first sun gear 36 and the second rotating member 29 are directly connected. Further, from the first rotating member 26Driving force is transmittedThe first sun gear 36 is engaged with the inner side of the first pinion gear 38, and the inner peripheral teeth 37 are engaged with the outer side of the first pinion gear 38.Driving force fromFirst output shaft 13 and intermediate output shaft 28Will be communicated to , High speed 4 wheel driveIt becomes a mode.
[0029]
If the center differential free state is selected during the high speed mode, the solenoid valve 49 is kept in a non-energized state, and at this time, the metering valve 52 blocks the third oil passage R3. In this case, the second clutch C2 is disengaged, the second rotating member 29 and the first output shaft 13 are divided, and a center differential free state is established.
If the center differential lock state is in the high speed mode, the solenoid valve 49 is energized, and the metering valve 52 communicates with the third oil passage R3 in response to this, and the high pressure oil is sent from the metering valve 52 to the first oil passage 411, first The oil is supplied to the hydraulic chamber 42 of the second clutch C2 through the third oil passage R3 including the second central oil passage 41 in the output shaft 13, and the second rotating member 29 and the first output shaft 13 are directly connected to each other, so that the center differential lock is provided. It becomes a state.
[0030]
Low speed4 wheel driveWhen the mode is selected, as shown in FIG. 4A, the solenoid valve 47 is energized to open the first oil passage R1, the first brake B1 is joined, and the second sun gear 34 is stopped. Kept in a state. Further, the solenoid valve 48 is energized to open the second oil passage R2, and the first clutch C1 is turned on to eliminate the spring force and switch to the disconnected state. In this case, the second sun gear 34 and the second pinion gear 39 work, the rotation on the first rotating member 26 side is shifted to the low speed side with a low gear ratio, and the rotation is shifted to the rear wheel 27 side from the first output shaft 13. It is transmitted to the front wheel 59 side via the second clutch C2.
For such a normal operation of the transfer structure, an abnormal operation (fail operation) as shown in FIG. 7 can be considered.
[0031]
Here, FIG. 7 shows the on / off states of the first brake B1 and the first clutch C1 according to the switching of the height (Hi, Lo) of the transfer speed change element of FIG. Here, the first switching B1 and the first clutch C1 for switching between high and low (Hi, Lo) are normally achieved in a predetermined switching mode when the hydraulic pressure is low or when both hydraulic pressure is high. If the level is different, it can be considered a malfunction.
When the transfer structure having such characteristics is driven, a switching abnormality occurs in the electromagnetic valves 47 and 48, the metering valves 50 and 51, etc., and the first hydraulic pressure p1 and the first hydraulic pressure p1 in the first and second oil passages R1 and R2 are increased. It is assumed that the 2 oil pressure p2 changes its oil pressure level relatively high and low.
[0032]
In this case, as shown in FIGS. 5A and 5B, the left and right pressure receiving portions 561 and 562 of the spool 56 in the fail safe valve 55 have a difference Δp between the first hydraulic pressure p1 and the second hydraulic pressure p2 that are different in level. When it is pressed to one side by the load multiplied by the pressure receiving area Af and the same value exceeds the set load Fo (Δp × Af> Fo), the neutral spring 57 is elastically displaced to simultaneously shut off the first oil path R1 and the second oil path R2. To do.
[0033]
By such oil path opening / closing control, the first hydraulic pressure p1 and the second hydraulic pressure p2 that are different in level are applied to the first and second oil paths R1, R2, that is, the relative deviation between the first hydraulic pressure p1 and the second hydraulic pressure p2. If the pressing force equivalent to Δp (Δp × Af) exceeds the set load Fo, which is a predetermined value, it is considered that a malfunction has occurred and switching control is not performed. Conversely, the first hydraulic pressure p1 and the second hydraulic pressure p2 are both at the same hydraulic pressure level, that is, the pressing force (Δp × Af) corresponding to the relative deviation Δp between the first hydraulic pressure p1 and the second hydraulic pressure p2 is a predetermined value. If it is within a certain set load Fo, it is considered that the operation is normal, and switching control is performed.
[0034]
As a result, in the region where the set load Fo is exceeded, the first oil passage R1 and the second oil passage R2 are shut off, so that the first brake B1 and the first clutch C1 can be prevented from malfunctioning. Operation can be reliably prevented.
[0035]
In particular, in the dead zone where the hydraulic pressure corresponding to the deviation Δp between the first hydraulic pressure p1 and the second hydraulic pressure p2 does not exceed the set load Fo which is the dead zone set value, the hydraulic pressure switching control operation can be performed as usual. Even if a relative response difference between the first oil pressure R1 and the second oil pressure p2 of the first oil path R1 and the second oil path R2 occurs due to the setting of the dead zone, such a response difference occurs. If the oil path R1 and R2 are shut off by the deviation Δp, unnecessary switching can be prevented.
[0036]
Furthermore, since the fail-safe valve 55 is equipped with the neutral spring 57, the dead zone can be easily set. Further, the first clutch C1 can reliably perform the clutch connecting / disconnecting operation in which the speed change element is joined by a spring force, and when the hydraulic chamber 44 receives the oil pressure, the spring force is released and the clutch disengaged state is maintained. it can.
[0037]
【The invention's effect】
The first invention distributes the driving force from the driving force source to the front wheel side output unit and the rear wheel side output unit by the center differential, and is a hydraulic type that is interposed in the front wheel side output unit by the hydraulic pressure from the hydraulic source. 1clutchAnd a hydraulic second interposed between the front wheel side output section and the rear wheel side.clutchCan be selectively engaged, especially when hydraulic pressure is not applied.clutchIs provided in the engaging direction, so that at least the hydraulic firstclutchThe engagement of the front wheel side output portion by the urging force of the urging means is joined, and the hydraulic firstclutchWhen the hydraulic pressure is received, the urging force is released and the clutch disengaged state is maintained, so that the switching operation can be surely performed when the hydraulic pressure is switched, and the reliability of the switching operation is increased.
[0038]
According to a second aspect of the present invention, the valve device is hydraulic only when the hydraulic pressure deviation of the first and third hydraulic supply oil passages is in a dead zone below a predetermined value.clutchAnd hydraulicbrakeWhen the hydraulic pressure deviation of the first hydraulic supply oil passage and the third hydraulic supply oil passage is large, both oil passages are shut off and hydraulicclutchAnd hydraulicbrakeIt is possible to reliably prevent the switching that becomes inactive and malfunctions. For this reason, abnormal driving force transmission due to malfunction of the hydraulic circuit and the drive system interlock state can be avoided, and the durability of the apparatus can be improved.
[0039]
According to a third aspect of the present invention, there is provided the transfer device for a four-wheel drive vehicle according to the second aspect, wherein the valve device is in particular.Deviation between the hydraulic pressure supplied to the hydraulic clutch and the hydraulic pressure supplied to the hydraulic brakeSince a neutral spring that can regulate the switching operation of the valve device within a predetermined value is mounted, the dead zone can be easily set and a reliable device can be provided.
[0040]
According to a fourth aspect of the present invention, there is provided a transfer device for a four-wheel drive vehicle according to the second aspect of the present invention.clutchThe first shifting element is joined by a spring force, and when the first hydraulic actuator receives the hydraulic pressure, the spring force is released and the clutch disengaged state is maintained. Can provide a reliable device.
[Brief description of the drawings]
FIG. 1 is a skeleton diagram showing a schematic configuration of a transfer equipped with a transfer structure as one embodiment of the present invention.
FIG. 2 is a cross section of the transfer of FIG.
FIG. 3 is a hydraulic circuit diagram of the transfer of FIG. 1;
FIGS. 4A and 4B are diagrams for explaining a normal function of the fail-safe valve provided in the transfer structure of FIG. 1, in which FIG. 4A shows a hydraulic pressure on state and FIG. 4B shows a hydraulic pressure off state;
FIG. 5 is a diagram illustrating a function when the hydraulic pressure levels of the first clutch and the first brake are different from each other when the fail-safe valve equipped in the transfer structure of FIG. 1 fails, and (a) (B) shows the case where the hydraulic pressure on and off states are opposite to each other.
6 is a skeleton diagram of the transfer structure of FIG. 1. FIG.
7 is an explanatory diagram showing ON / OFF of each shifting element corresponding to a switching operation mode and a malfunction in the hydraulic circuit having the transfer structure shown in FIG. 1;
[Explanation of symbols]
11 Transfer
111 High / Low switching mechanism
112 2WD 4WD switching mechanism
13 First output shaft
22 Output shaft of automatic transmission
26 First rotating member
27 Front wheel
28 Intermediate output shaft
29 Second rotating member
32 Third rotating member
33 cylindrical shaft
34 Second Sun Gear
35 casing
36 1st Sun Gear
37 internal teeth
38 1st pinion gear
39 Second pinion gear
47 Solenoid valve
48 Solenoid valve
49 Solenoid valve
55 Fail-safe valve
57 Neutral spring
59 Rear wheel
B1 First brake
C1 1st clutch
C2 Second clutch
A / T automatic transmission
p1 1st hydraulic pressure
p2 Second hydraulic pressure
R1 1st oil passage
R2 Second oil passage
Δp deviation
Fo set load

Claims (4)

A transfer for a four-wheel drive vehicle having a center differential that distributes a driving force from a driving force source to a front wheel side output unit and a rear wheel side output unit and allows differential between the front wheel side output unit and the rear wheel side output unit. In the device
The center differential is
A first element coupled to the driving source for inputting the driving force; a second element for transmitting the driving force to the front wheel side output section; a third element for transmitting the driving force to the rear wheel side output section; A fourth element fixable to the member,
The transfer device further includes a hydraulic first clutch capable of engaging / disengaging the front wheel side output portion and the second element;
A hydraulic second clutch capable of engaging / disengaging the front wheel side output section and the third element;
A hydraulic brake that allows the fourth element to be engaged / released with respect to the fixed member, and an urging means that engages the hydraulic first clutch when hydraulic pressure is not supplied,
The hydraulic second clutch engages the front wheel side output section and the third element when hydraulic pressure is supplied,
The hydraulic brake fixes the fourth element when hydraulic pressure is supplied,
The transfer device for a four-wheel drive vehicle, wherein the hydraulic first clutch engages the front wheel side output portion and the second element by the biasing means when hydraulic pressure is not supplied. A first element that inputs a driving force from a driving force source; a second element that transmits the driving force to a front wheel side output unit; and a third element that transmits the driving force to a rear wheel side output unit, the driving force and the center differential to be distributed to the above front wheel side output section and the rear wheel side output section,
A hydraulic clutch that is arranged to hold the said second element and the front-wheel-side output section when receiving a hydraulic pressure to the disconnection state between said second element and the front-wheel-side output section of the center differential,
With a cleavable between the high-speed stage and the low speed stage of the rotational force output from the center differential according to oil pressure supplied, hydraulic brake hydraulic pressure to be supplied with the same hydraulic supply pattern and the hydraulic clutch When,
A first hydraulic supply oil passage to the hydraulic clutch ;
A third hydraulic supply oil passage to the hydraulic brake ;
A valve device disposed in common Ryoaburaro,
With
The valve device deviation of the oil pressure supplied to the oil pressure supplied and the hydraulic brake to said hydraulic clutch only when exceeding a predetermined value, a blocking supply of hydraulic pressure to the hydraulic clutch and the hydraulic brake A transfer device for a four-wheel drive vehicle, which is a feature. The transfer device for a four-wheel drive vehicle according to claim 2,
The four-wheel wheel, wherein the valve device is equipped with a neutral spring capable of regulating a switching operation of the valve device when a deviation between a hydraulic pressure supplied to the hydraulic clutch and a hydraulic pressure supplied to the hydraulic brake is within a predetermined value. Drive car transfer device. The transfer device for a four-wheel drive vehicle according to claim 2,
The four-wheel drive is characterized in that the hydraulic clutch has a first shifting element joined by a spring force, and when the first hydraulic actuator receives a hydraulic pressure, the spring force is released and the clutch disengaged state is maintained. Car transfer device.

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