JPH09150641A - Four-wheel drive vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently secure a car room space by lightening a four-wheel drive vehicle in the same degree as a two-wheel drive vehicle and improving a boarding property to the inside of an engine room. SOLUTION: This is a four-wheel drive vehicle furnished with a fluid pressure pump 6 to transmit driving force to a drive axle through a transmission from a main motor and to discharge working fluid by transmission of the driving force, a fluid pressure motor to rotate by interlocking with a driven axle and channels respectively communicated between the fluid pressure pump 6 and the fluid pressure motor. Additionally, a pump installation part 34d to open toward a final gear of the transmission disposed in this casing is formed on casings 22a, 24a of the transmission. The fluid pressure pump is installed on the casings in a state where a pump drive shaft 6a is inserted into the casings from the pump installation part 34d, it is engaged with the final gear through a drive gear and a pump main body is externally installed on an outer edge part of the pump installation part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a four-wheel drive vehicle in which a rotary driving force generated by a main engine is transmitted to front wheels and rear wheels.

[0002]

2. Description of the Related Art As a drive transmission system for a four-wheel drive vehicle that transmits the rotational drive force of a main prime mover to front wheels and rear wheels, the drive force transmitted from the main prime mover to a transmission is distributed to front and rear wheels. A system is known that includes a transfer mechanism that controls the ratio and a propeller shaft that transmits the driving force controlled by the transfer mechanism to the front wheel side and the rear wheel side. However, since this drive transmission system has a transfer mechanism and a propeller shaft, it has an increased weight, a bad effect on the vehicle interior space, and a deterioration in fuel consumption as compared with a two-wheel drive vehicle.
We cannot avoid the deterioration of noise and vibration.

Therefore, as described in, for example, Japanese Unexamined Patent Publication No. 1-223030 (hereinafter, referred to as a conventional example), it rotates in conjunction with a drive axle to which a driving force is transmitted from a main prime mover and responds to a rotational speed. A hydraulic pump that generates
It has a configuration including a hydraulic motor that rotates in conjunction with the driven axle to generate hydraulic pressure according to the rotation speed, and an oil passage that connects the discharge port of one of the hydraulic pump and the hydraulic motor and the suction port of the other. A fluid pressure four-wheel drive vehicle has been proposed.

According to this conventional four-wheel drive vehicle, since the transfer mechanism and the propeller shaft are omitted, the weight of the vehicle and the space inside the vehicle can be secured as compared with other four-wheel drive vehicles. .

[0005]

By the way, although a prime mover, a transmission, etc. are mounted in the engine room, in the conventional four-wheel drive vehicle described above, the drive force from the main prime mover is transmitted through the transmission. Is a large-sized device, and it is mounted in the engine room occupying a position different from the position where the transmission is mounted, so it is difficult to reduce the weight of the vehicle compared to a two-wheel drive vehicle. However, it is also disadvantageous in terms of fuel consumption. Moreover, since a large hydraulic pump is mounted in the engine room, it is difficult to secure a sufficient vehicle interior space.

Therefore, the present invention has been made by paying attention to the unsolved problem of the above-mentioned conventional example, and it is possible to achieve the same weight reduction as that of a two-wheel drive vehicle, and moreover, it is possible to provide the same in the engine room. It is an object of the present invention to provide a four-wheel drive vehicle capable of improving mountability and ensuring a sufficient vehicle interior space.

[0007]

In order to achieve the above object, the invention of claim 1 is a drive axle to which a driving force is transmitted from a main prime mover via a transmission, and a driving force transmission from the main prime mover side. The fluid pressure pump for discharging the working fluid, the fluid pressure motor rotating in conjunction with the driven axle, and the fluid pressure pump and one of the fluid pressure motor's discharge port and the other suction port respectively communicate with each other. In a four-wheel drive vehicle having a flow path, a casing of the transmission is provided with a pump mounting portion that opens toward a final gear of the transmission disposed in the casing, and the fluid pressure pump is provided in the pump main body. The pump drive shaft projects from the pump drive shaft, and the drive gear is coaxially connected to the pump drive shaft. Inserted the pump drive shaft, while meshed with the final gear via the drive gear, the hydraulic pump was attached to the casing in a state in which the pump body and external to the outer edge of the pump mounting portion.

According to the invention described in claim 1, as compared with the conventional four-wheel drive vehicle in which a transfer force, a propeller shaft and the like are used as a drive force transmission system, the weight reduction and the interior space of the vehicle can be significantly improved. Moreover, in the fluid pressure pump, the pump drive shaft meshes with the final gear of the transmission through the drive gear, and it is possible to integrally connect the final gear of the transmission to the casing of the transmission by using the minimum number of gears and bearing members.

According to a second aspect of the present invention, in the four-wheel drive vehicle according to the first aspect, the main prime mover is laterally arranged in the engine room, and the main prime mover is arranged in the vehicle width direction with respect to the main prime mover. In the casing of the transmission arranged on one side, an input shaft to which a driving force is transmitted from the main prime mover, and a final gear to which the driving force is transmitted from the input shaft via another transmission shaft and a transmission gear. And the axes are arranged so as to extend in the vehicle width direction while being separated from each other in parallel to the front-rear direction of the vehicle, and an arbitrary plane including the input shaft and the axis of the final gear is taken as a reference plane. The fluid pressure pump is attached to the casing such that the axis of the pump drive shaft is located above the reference plane and extends in the vehicle width direction.

According to the second aspect of the invention, from an arbitrary plane (reference plane) including the input shaft of the transmission and the axis of the final gear, which extend in the vehicle width direction while being separated from each other in parallel with the front-rear direction of the vehicle. The hydraulic pump is integrally connected to the casing so that the axis of the pump drive shaft is located in the upper position, so the length of the transmission in the vehicle front-rear direction does not increase and it is easy to mount in the engine room. Becomes

The invention of claim 3 is the same as claim 1 or 2.
In the four-wheel drive vehicle described above, the pump mounting portion of the casing is formed at a predetermined position of the casing that does not face the main engine, and the pump main body externally attached to an outer edge portion of the pump mounting portion is Separated from the main engine. According to the third aspect of the present invention, even if the temperature of the working fluid in the fluid pressure pump rises for some reason, there is no risk of exerting a thermal influence on the air supply system of the main engine.

The invention according to claim 4 is the four-wheel drive vehicle according to any one of claims 1 to 3, wherein the pump mounting portion of the casing is an oil of lubricating oil supplied into the casing. Formed above the level. According to the invention described in claim 4, there is no possibility that the lubricating oil with low cleanliness inside the casing will flow into the pump body, and the working oil inside the pump body will always have high cleanliness.

Further, the invention of claim 5 is the same as claim 1.
The four-wheel drive vehicle pump body according to any one of
A fitting portion that fits into the pump mounting portion is formed, and a ring groove is formed in the circumferential direction of either the outer circumference of the fitting portion or the inner circumference of the pump mounting portion, and the ring-shaped oil is formed in the ring groove. A seal member was attached. According to the invention described in claim 5, the fluid-tight structure of the fluid pressure pump and the pump mounting portion is ensured with high accuracy, and the liquid-tight structure is secured only by fitting the fitting portion of the pump body into the pump mounting portion. Because it is done
The connection work of the fluid pressure pumps can be simplified.

Further, the invention according to claim 6 is the four-wheeled vehicle according to any one of claims 1 to 5, wherein the pump drive shaft is kept liquid-tight on the outer periphery of the base end side of the pump drive shaft. A ring-shaped oil seal member was attached. According to the invention described in claim 6, the liquid tightness of the working fluid inside the pump body can be maintained with high accuracy, and
There is no possibility that lubricating oil with low cleanliness inside the casing will flow into the pump body.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a first embodiment when the present invention is applied to a four-wheel drive vehicle based on a front-wheel drive vehicle. Reference numeral 1 in the figure denotes an engine as a main prime mover, the rotational driving force of the engine 1 is input to a front wheel side differential gear 3 via a transmission 2, and an output side of the front wheel side differential gear 3 serves as a drive axle. Front wheels 5 are connected via a front axle 4.

The front wheel side differential gear 3 is formed in the differential gear case 3a while the final gear 3b integrally connected to the differential gear case 3a meshes with the reduction gear 2b connected to the reduction shaft 2a of the transmission 2. A pinion 3d is attached to the pinion shaft 3c thus formed, a pair of side gears 3e mesh with these pinion 3d, and the front axle 4 is connected to these side gears 3e. A drive gear 6b connected to a pump drive shaft 6a of a fluid pressure pump 6, such as a suction throttle piston pump, is meshed with the final gear 3b, which serves as an input gear of the front wheel differential gear 3.

The suction port 6c of the fluid pressure pump 6 is connected to a strainer 7a arranged in the reservoir tank 7 through a suction pipe 8S, and two positions are provided through a low pressure pipe 8L as a low pressure passage. The 4-port electromagnetic directional control valve 9 is connected to the tank port T, and the discharge port 6d is connected to the pump port P serving as the suction port of the forward / backward switching electromagnetic directional control valve 9 through the high pressure pipe 8H serving as a high pressure passage. ing. Here, in the piston pump 6, the suction port and the discharge port are not interchanged depending on the rotation direction of the rotating shaft 6a, and the discharge flow rate thereof is "0" as shown by the characteristic curve L ₁ in FIG. It is set to increase in proportion to the increase of the rotation speed during the period from to reaching the predetermined value V _1, and to be saturated at the maximum discharge flow rate Q _1MAX at the predetermined value V ₁ or more.

The electromagnetic directional control valve 9 for switching between forward and reverse travel is operated in the normal position where the solenoid 9a is in a non-energized state.
The pump port P serving as the suction port communicates with the output port A, and the tank port T serving as the discharge port communicates with the output port B.
Further, at the offset position where the solenoid 9a is in the energized state, the pump port P communicates with the output port B and the tank port T communicates with the output port A, and the output ports A and B are fluid such as a swash plate type variable displacement motor. The high pressure pipe 8H is connected to the suction / discharge ports 10a and 10b of the pressure motor 10 and the solenoid 9a is in a non-energized normal position.
Of high pressure oil to the suction / discharge port 10a of the fluid pressure motor 10,
The low-pressure pipe 8L is communicated with the suction / discharge port 10b, and the rotary shaft 10c is rotationally driven in the rotational direction during forward traveling, for example, clockwise when viewed from the left side surface, and conversely at the offset position.
Intake / discharge port 1 of fluid pressure motor 10 for high-pressure hydraulic oil H
The low-pressure pipe 8L is connected to the suction / discharge port 10a of the rotary shaft 10c to drive the rotary shaft 10c in the rotational direction during forward traveling, for example, in the counterclockwise direction when viewed from the left side surface.

The electromagnetic directional control valve 9 is built in the fluid pressure motor 10, and the suction / discharge ports 10a and 10 of the fluid pressure motor 10 are provided without the output ports A and B passing through pipes.
connected to b. Further, the solenoid 9a of the electromagnetic directional control valve 9 is energized by being connected to the DC power supply 9c via a shift position detection switch 9b which is turned on when a backward movement is selected by a shift lever (not shown), whereby the vehicle travels forward. It is controlled to be in a non-energized state at times and to be in an energized state during backward traveling.

The flow rate of the fluid pressure motor 10 is the differential pressure generated at both ends of the differential pressure detecting orifice 11 inserted in the low pressure pipe 8L near the tank port T of the electromagnetic directional control valve 9 and includes the hydraulic cylinder 12a. Swash plate variable mechanism 1
By controlling the 2, as indicated by the characteristic curve L ₂ in FIG. 2, when it reaches increased in proportion to the increase of the rotational speed to the rotational speed V ₁ it was in until the rotational speed reaches V ₁ ,
The discharge flow rate Q ₂ becomes larger than the maximum discharge flow rate Q _1MAX of the piston pump 6, and thereafter, increases relatively gently as the rotation speed increases. Here, the discharge flow rate of the fluid pressure motor 10 and the discharge flow rate of the fluid pressure pump 6 are as shown in FIG.
The specific discharge flow rate and the gear ratio of the gears connected to the rotating shaft are set so that the discharge flow rate of the fluid pressure motor 10 becomes higher than the discharge flow rate of the fluid pressure pump 6 for the same wheel speed.

Between the suction port 6c and the discharge port 6d of the fluid pressure pump 6, a relief valve 13 that determines the upper limit of the discharge pressure of the fluid pressure pump 6 is inserted, and the fluid pressure pump 6 and the electromagnetic direction are set. A check valve 13 that allows a fluid flow from the low-pressure pipe 8L side to the high-pressure pipe 8H side is inserted in a communication pipe 12 that communicates between the high-pressure pipe 8H and the low-pressure pipe 8L between the switching valves 9. Further, a fixed orifice 15 is connected in parallel with the check valve 13 to the communication pipe 14 arranged in parallel with the communication pipe 12.

A drive gear 10d is coaxially attached to the rotary shaft 10c of the fluid pressure motor 10.
The ring gear 17b formed in the differential gear case 17a of the rear wheel side differential gear 17 at 0d.
Are engaged. This rear wheel side differential gear 1
The pinion 17d is attached to the pinion shaft 17c formed in the differential gear case 17a, and the pair of side gears 17e meshes with the pinion 17d. Rear axle 1
8 are connected, and a rear wheel 19 is connected to the rear axle 18.

Next, the operation of the four-wheel drive vehicle of this embodiment will be described. Now, when the vehicle stops on a high friction coefficient road such as a dry road surface and starts forward traveling in a braking state where the engine 1 is in an idling state, the vehicle can be started by switching the shift lever to the forward traveling side. However, at this time, the shift position detection switch 9b on the reverse traveling side is maintained in the OFF state, so the solenoid 9a of the forward / reverse switching electromagnetic directional control valve 9 is maintained in the non-energized state, and the switching position is changed to the state shown in FIG. Continue the normal position shown. In this state, by releasing the brake pedal and stepping on the accelerator pedal, the rotational force of the engine 1 is transmitted to the front wheel side differential gear 3 via the transmission 2.
Forward rotation is started by rotationally driving the front wheels 5 in the forward direction by the front wheel side differential gear 3. here,
The discharge flow rates of the fluid pressure pump 6 and the fluid pressure motor 10 are shown in FIG.
As shown in, at the same rotation speed Vr, the fluid pressure motor 1
Since the discharge flow rate of 0 is set to be larger than that of the piston pump 6, the high-pressure hydraulic oil discharged from the fluid pressure pump 6 is sucked by the fluid pressure motor 10, so that the pressure of the high pressure pipe 8H is I can't go up. That is,
The fluid pressure motor 10 does not act as a motor, the driving force is not transmitted to the rear wheels 19, and the vehicle travels forward in a state similar to that of a front-wheel drive vehicle. At this time, since the suction flow rate of the fluid pressure motor 10 exceeds the discharge flow rate of the fluid pressure pump 6, the shortage amount is the low pressure pipe 8L, the communication pipe 12, and the check valve 1.
Replenished via 3.

Next, on low-friction coefficient roads such as frozen roads and snowfall roads
When starting, the front wheels 5 are first driven to rotate, but with low friction.
Because of the friction coefficient road, the front wheels 5 slip and the front wheels 5 and
There is a difference in rotational speed between the rear wheel 19 and the front wheel 5, which causes the high rotational speed of the front wheel 5.
Accordingly, the discharge flow rate of the fluid pressure pump 6 is equal to that of the fluid pressure motor 10.
If the discharge flow rate is exceeded, the resistance of the fluid pressure motor 10 will increase.
The resistance acts as a load and the working oil pressure of the high-pressure pipe 8H rises.
Therefore, the fluid pressure motor 10 operates as a motor.
By the way, the driving force corresponding to the pressure in the high pressure pipe 8H is applied to the rear wheel.
It is transmitted to the rear wheel 19 via the differential gear 17.
You. That is, the torque transmitted to the rear wheel 19 side is
It occurs only when there is a difference in rotation speed between the wheels,
Both increase sharply and maximum due to pressure limitation by relief valve 11
Torque T _MAXWill be regulated. Also, the rear wheel 19
The torque transmitted to the side has a smaller rotational speed difference at lower speeds.
It has the characteristic that it can easily generate driving force.
And the discharge flow rate characteristics of the fluid pressure pump 6 and the fluid pressure motor 10.
The flow rate in the proper range of the
Is caused by an increase in. Flow rate of this Figure 2
Due to the characteristics, the higher the flow rate difference, the larger
Therefore, when driving at high speed without the need for four-wheel drive, four-wheel drive
It has a characteristic that it is hard to become a driving vehicle, and the wheel speed is shown in Fig. 2.
Between 0 and Vr, torque rises as vehicle speed increases
Although the number difference becomes large, the torque becomes higher when the wheel speed is Vr or higher.
Does not occur.

Next, when the vehicle is moved backward, the shift position detection switch 9b is turned on by switching the shift lever to the reverse position, so that the solenoid 9a of the forward / reverse switching electromagnetic directional control valve 9 is energized. Then, the switching position is switched from the normal position to the offset position, whereby the working oil in the high-pressure pipe 8H is supplied to the suction / discharge port 10b of the fluid pressure motor 10, and the suction / discharge port 10 is supplied.
By returning the hydraulic oil discharged from a to the low-pressure pipe 8L side, the rotary shaft 10c of the fluid pressure motor 10 is reversed from that during forward traveling, and the rear wheel 19 is rotated in reverse. Therefore, when the vehicle is moving backward, the transmission of the driving force is exactly the same as when moving forward, and pressure is generated in the high-pressure pipe 8H only when the front wheel 5 slips and the rotational speed difference between the front and rear axles 4 and 18 occurs. However, when the driving force is transmitted to the rear wheel 19 and the shortage of the intake amount of the fluid pressure motor 10 when the rotational speed difference between the front and rear axles 4 and 18 is small, the low pressure pipe 8L, the communication pipe 12 and the check valve 13 are used. Will be replenished via.

Therefore, the four-wheel drive vehicle of this embodiment is
A fluid pressure pump 6 that rotates in conjunction with the front wheel axle 4 that is a drive axle, a fluid pressure motor 10 that rotates in conjunction with the rear wheel axle 18 that is a driven axle, and between the fluid pressure pump 6 and the fluid pressure motor 10. A conventional four-wheel drive vehicle in which the propelling shaft is used to transmit the driving force between the front and rear wheels because the driving force transmission system using fluid pressure having the pipes 8H and 8L for connecting the Compared with, it is possible to reduce the weight and significantly improve the vehicle interior space.

Next, FIG. 3 shows the transmission 2 and the front wheel side differential gear 3 shown in FIG.
The specific structure of the engine 1, that is, the engine 1 is installed horizontally (engine 1
Of the automatic transmission axle 20 for FF (front engine / front drive) (hereinafter, referred to as a crankshaft extending in the vehicle width direction), in which the transmission 2 and the front wheel side differential gear 3 are integrally arranged in the same casing. It is shown as applied to a transaxle 20).

Reference numeral 22a in FIG. 3 denotes a converter casing, and the converter casing 22a shown in FIG.
Of the transmission casing 24a is connected to the end of the engine 1 in the vehicle width direction via a connecting bolt, and the flange located on the left side of the converter casing 22a is located on the right side of FIG. It is connected with a connecting bolt. Note that reference numeral 23
Is a side cover connected to the left flange portion of the transmission casing 24a via connecting bolts.

Then, the converter casing 22a
Inside, a torque converter 22 that is connected to the output shaft 1a of the engine 1 is arranged. That is, the torque converter 22 has a lockup mechanism, and mechanically connects the pump impeller 22c and the turbine runner 22d, which are connected to the output shaft 1a, by controlling the hydraulic pressure in the lockup oil chamber 22b. It can be separated. The converter output shaft 22e connected to the tabine runner 22d is connected to the transmission case 2
A bearing is rotatably supported in the bearing 4a, and is coaxially connected to one end of an output shaft (input shaft) 24b extending in the vehicle width direction.

Inside the transmission case 24a, the output shaft 24b is provided with a forward / reverse switching mechanism 24c equipped with a planetary gear mechanism, a forward clutch and a reverse brake, and the output shaft 24b is provided with other components. An output gear 24e is coaxially attached to the end (the left end in FIG. 3). Further, in the transmission case 24a, the reduction shaft 2a described with reference to FIG. 1 is arranged in parallel with the output shaft 24b so as to extend in the vehicle width direction and to be rotatably supported by bearings. The idler gear 24f coaxially attached to one end side (left side of FIG. 3) of the reduction shaft 2a meshes with the output gear 24e, and the other end portion (right side of FIG. 3) of the reduction shaft 2a is The reduction gear 2b described in FIG. 1 is coaxially attached.

As shown in the lower side of FIG. 3, the converter casing 22a and the transmission casing 24a connected to each other form a differential housing 26 therein, and the differential housing 26 is rotatably supported by a bearing in the differential housing 26. A supported differential gear case 3a is arranged. Then, a final gear 3b integrated with the differential gear case 3a via a connecting bolt.
, Meshes with the reduction gear 2b. The converter casing 22a and the transmission casing 23a are formed with first shaft insertion portions 26a and 26b for passing the front axles 4 on the left and right sides of the front wheels to connect with the side gears 3e of the differential gear 3.

Thus, the rotational driving force transmitted to the converter output shaft 22e via the engine 1 and the torque converter 22 is controlled in the rotational direction by the forward / reverse switching mechanism 24c, and then the output shaft 24b and the output shaft 24b are output. The gear 24e, the idler gear 24f, the reduction shaft 2a, the reduction gear 2b, the final gear 3b and the front wheel side differential gear 3 are transmitted to the front wheel left and right front axles 4.

Here, as shown in the lower side of FIG. 3, the fluid pressure pump 6 rotating in conjunction with the front axle 4 is a pump body 6
c is attached to the pump housing 30 of the transaxle 20 while being externally attached to the transmission casing 24a side and extending in the vehicle width direction. That is, the structures of the fluid pressure pump 6 and the pump housing 30 will be described in detail with reference to FIGS. 4 and 5. FIG. 4 shows the inside of the converter casing 22a when the transaxle 20 is mounted in the engine room. The left-right direction in this figure is the vehicle front-rear direction, and the front-back direction in this figure is the vehicle width direction. Further, the line indicated by the symbol L indicates the lowest position of the transaxle 20 in the engine room. Further, FIG. 5, A-P ₂ -A' in FIG
The transmission casing 2 has a sectional structure taken along the line
4a shows a structure in which the fluid pressure pump 6 is mounted.

According to FIG. 4, the converter casing 22
A second shaft insertion portion 28 that inserts the converter output shaft 22e of the torque converter 22 is formed at a substantially central portion of a, and the axis line of the converter output shaft 22e is indicated by a symbol P ₁ . In addition, the first shaft insertion portion 2 that inserts the front axle 4 described above.
6a is provided below the second shaft insertion portion 28 in the vehicle front-rear direction, and when the axis line of the front axle 4 is indicated by the reference symbol P ₂ , the differential housing 26 has the axis line P of the front axle 4. It is provided within a circular area indicated by a broken line centered on ₂ .

Here, the axis P of the converter output shaft 22e
_When an arbitrary plane including ₁ and the axis P ₂ of the front axle 4 is indicated by a symbol Q, the converter-side housing 32 is formed above the arbitrary plane Q. The converter-side housing 32 includes the transmission casing 24a.
The pump housing 30 for mounting the above-mentioned fluid pressure pump 6 is formed by being integrated with the mission side housing 34 formed in the above. In FIG. 4,
The reference numeral P ₃ in the converter-side housing 32 is the axis of the pump drive shaft 6a.

The converter-side housing 32 is shown in FIG.
As also shown in FIG. 3, an opening 32a is formed toward the transmission casing 24a side in the vehicle width direction, a flange 32b is formed on the peripheral edge of the opening 32a, and a plurality of bolt insertion holes are formed in the circumferential direction of the flange 32b. 32c is formed. In addition, the mission side housing 34
Has an opening 34a formed toward the converter casing 22a side in the vehicle width direction, a flange 32b is formed at the peripheral edge of the opening 34a, and is fitted to the outside of the transmission casing 24a in the circumferential direction of the flange 32b. A plurality of bolt insertion holes 34c are formed. A pump mounting portion 34d having a circular opening is formed on the opposite side of the opening 34a in the vehicle width direction, that is, on the outer side of the transmission casing 23a. The ring-shaped housing mounting portion (fitting portion) 6f of the fluid pressure pump 6 is fitted into the pump mounting portion 34d.

Then, the plurality of bolt insertion holes 32c, 34
By bringing the flanges 32b and 34b into contact with each other by making them correspond to each other, as shown in FIG.
A housing space 30a is formed between 34a, and the housing space 30a communicates with the differential housing 26 provided on the lower side. On the other hand, the fluid pressure pump 6
Is a pump main body 6c, a pump drive shaft 6a that is axially supported by a radial bearing 6d and projects outward from the pump main body 6c, and a sleeve that is spline-coupled to the pump drive shaft 6a and has a drive gear 6b formed on the outer circumference. And 6d. A screw hole 6e is formed on the end surface of the pump body 6c at a position corresponding to the bolt insertion hole 34c of the mission-side housing 34, and
The above-described ring-shaped housing mounting portion (fitting portion) 6f surrounds the pump body 6 so as to surround the base end side of the pump drive shaft 6a.
c. Then, the sleeve 6d includes the converter-side housing 32 and the mission-side housing 34.
Radial bearings 36a, 36b arranged on the inner peripheral wall of the
The final gear 3b of the front wheel differential gear 3 meshes with the drive gear 6b formed on the outer periphery of the drive gear 6b. And the connecting bolt 3
8 through the bolt insertion holes 32c and 34c and screw holes 6
The fluid pressure pump 6 is attached to the pump housing 30 by screwing it into the pump housing 30. Here, the line indicated by reference symbol L ₁ in FIGS. 4 and 5 indicates the maximum level of the lubricating oil supplied into the transaxle 20 for lubricating and cooling the gears and bearings. In addition, the line indicated by reference numeral L ₂ in FIG.
Indicates the lowest position of.

FIG. 6 is an enlarged view of the vicinity of the housing mounting portion 6f. A ring groove 6g is formed on the outer periphery of the housing mounting portion 6f fitted in the pump mounting portion 34d, and A ring-shaped oil seal member 6h is mounted in the ring groove 6g. Further, the ring member 6j inserted into the housing mounting portion 6f comes into contact with the side surface of the radial bearing 6d.
The axial movement of the radial bearing 6d is restricted by the contact of the adjusting shim 6k engaged with the inner peripheral portion of the housing mounting portion 6f on the side surface of j, but the ring member 6j and the pump drive shaft 6a are restrained. A ring-shaped oil seal member 6m is also installed between them. further,
A ring groove 6p is also formed on the outer periphery of the ring member 6j, and a ring-shaped oil seal member 6r is attached to the ring groove 6p.

Next, the function and effect of the fluid pressure pump 6 of this embodiment described with reference to FIGS. 3 to 6 will be described below. First, as shown in FIG. 5, the pump housing 3
The fluid pressure pump 6 attached to 0 is the fluid pressure pump 6
The drive gear 6b coaxially connected to the pump drive shaft 6a of
When the final gear 3b is meshed with the final gear 3b of the front-wheel differential gear 3 and the final gear 3b is rotated by the transmission of the rotational driving force from the engine 1 side to the front-wheel differential gear 3, the structure is such that it is driven as a pump. Uses only the minimum parts such as the sleeve 6d having the drive gear 6b formed on the outer periphery and the radial bearings 36a and 36b for rotatably supporting the sleeve. Therefore, the structure for mounting the fluid pressure pump 6 can be made lightweight. And it can be made compact.

Further, as shown in FIG. 4, the pump drive shaft 6a of the hydraulic pump 6 over any plane Q containing the axis P ₂ of the axes P ₁ and the front axle 4 of the converter output shaft 22e
Since the fluid pressure pump 6 is mounted on the upper part of the differential housing 26 such that the axis P ₃ of the vehicle is located, the length of the transaxle 20 in the vehicle front-rear direction does not increase and the mountability in the engine room is improved. Can be good. Further, since the lowest position L ₁ of the transaxle 20 mounted in the engine room does not change, the lowest ground clearance of the vehicle is not impaired.

Further, as shown in FIG. 3, the fluid pressure pump 6 has a pump housing 6 with its pump body 6c externally attached to the transmission casing 24a side.
0, that is, since the fluid pressure pump 6 is disposed at a position sufficiently separated from the engine 1 with the converter casing 20a interposed therebetween, the operation in the fluid pressure pump 6 is caused for some reason. Even if the fluid temperature rises, there is no danger of heat affecting the air supply system of the engine 1 and the like.

Further, in the pump mounting portion 34d of the pump housing 30 into which the housing mounting portion 6f of the fluid pressure pump 6 is fitted, its lowest position L ₂ is above the highest level L ₁ of lubricating oil in the transaxle 20. Is formed so that there is no possibility that lubricating oil with low cleanliness inside the transaxle 20 will flow into the fluid pressure pump 6,
Since the hydraulic oil in the fluid pressure pump 6 always has high cleanliness, the fluid pressure pump 6 can be normally driven. On the other hand, with the above structure, when the hydraulic oil inside the fluid pressure pump 6 leaks and flows into the transaxle 20 due to a defective oil seal, the amount of lubricating oil in the transaxle 20 increases, It is conceivable that this increase in the amount of lubricating oil is detected by, for example, an oil level cage provided in a reservoir tank and an alarm is issued. Therefore, it is possible to detect early that the fluid pressure pump 6 is defective, so that the fail-safe mechanism of the fluid pressure pump 6 can be provided.

Furthermore, as shown in FIG. 6, the pump mounting portion 34d of the pump housing 30 and the fluid pressure pump 6 are
Oil seal member 6h between the housing mounting portion 6f and
Is mounted, an oil seal member 6m is mounted between the pump drive shaft 6a and the inner circumference of the ring member 6j, and an oil seal member 6r is also mounted between the outer circumference of the ring member 6j and the housing mounting portion 6f. Therefore, the liquid tightness in the pump housing 30 can be maintained with high accuracy. Before mounting the fluid pressure pump 6 on the pump housing 30, the oil seal members 6m and 6r can be mounted on the outer circumference of the pump drive shaft 6a in advance, and the oil seal member 6h can be mounted on the housing mounting portion 6f. Since the fluid-tight structure is obtained by being fitted in the ring groove 6g formed on the outer periphery and only by fitting the housing mounting portion 6f into the pump mounting portion 34d, the fluid pressure pump 6 can be easily mounted.

In the above embodiment, the positions of the transaxle 20, the fluid pressure pump 6 and the like have been described in terms of the vehicle width direction and the vehicle front-rear direction, but the present invention is not limited to this embodiment, and the above-described operational effects are obtained. Needless to say, this embodiment may be different from that of the present embodiment. Further, although the case where the rear wheel side differential device 17 is provided has been described, the present invention is not limited to this, and the rear wheel differential device 17 is omitted, and instead of this, the left and right rear wheels 19L, 1 are provided.
9R left and right axles 18L, 18R individually fluid pressure motor 1
0L and 10R may be provided. In this case, when the left and right wheels have different loads when turning, the fluid flow motors 10L and 10R naturally discharge the discharge flow rate according to the difference. Since the difference is generated, the differential function equivalent to that of the differential device can be exhibited.

In each of the above-described embodiments, the case where the forward / reverse switching electromagnetic directional control valve 9 is built in the fluid pressure motor 10 has been described, but the invention is not limited to this, and the fluid pressure motor 10 is not limited to this. It may be separately provided outside. Further, in the above-mentioned actual embodiment, the embodiment based on the front-wheel drive vehicle has been described, but the present invention is not limited to this, and the fluid-pressure pump 6 may be disposed on the rear-wheel side even when the vehicle is based on the rear-wheel drive vehicle. By arranging the motor 10 on the front wheel side,
The same operation and effect as the above embodiment can be obtained.

Furthermore, in each of the above embodiments,
The case where the discharge flow rate characteristics of the fluid pressure pump 6 and the fluid pressure motor 10 are shown in FIG. 2 has been described.
Discharge flow rate of the discharge flow rate characteristics, or held at a constant flow rate to stop the increase in the discharge flow rate when a predetermined wheel speed V ₁ or more, with respect to an increase of the wheel speed from the reference wheel velocity V ₁ is smaller than the wheel speed Vr May be gradually changed.

[0047]

As described above, according to the four-wheel drive vehicle of claim 1, the four-wheel drive vehicle rotates in conjunction with the fluid pressure pump that discharges the working fluid by the transmission of the driving force from the main engine side and the driven axle. Since the starting traveling operation is performed as a driving force transmission system by fluid pressure having a fluid pressure motor and a flow path connecting between the fluid pressure pump and the fluid pressure motor, the transfer, propeller shaft, etc. are used as the driving force transmission system. Compared with the conventional four-wheel drive vehicle, the weight reduction and the space inside the vehicle can be significantly improved.

In addition, the fluid pressure pump has a structure in which the pump drive shaft meshes with the final gear of the transmission through the drive gear and is mounted on the transmission casing using the minimum number of gears and bearing members. The pressure pump can be made lighter and more compact, and the same weight and space as the two-wheel drive vehicle can be secured.

Further, the invention according to claim 2 can obtain the effect according to claim 1, and further, the input shaft of the transmission and the final shaft extend in the vehicle width direction while being separated from each other in parallel with the longitudinal direction of the vehicle. Since the fluid pressure pump is attached to the casing so that the axis of the pump drive shaft is located above a given plane (reference plane) including the axis of the gear, the length of the transmission in the vehicle front-rear direction does not increase, The mountability in the engine room can be improved. Further, since the minimum position of the transmission mounted in the engine room does not change, the minimum ground clearance of the vehicle is not impaired.

Further, the invention according to claim 3 can obtain the effect according to claim 1 or 2, and since the pump main body is externally attached to the casing position which does not face the main prime mover, the fluid may be broken by some cause. Even if the temperature of the working fluid in the pressure pump rises, there is no risk of heat affecting the air supply system of the main engine. Further, according to the invention of claim 4, since the pump mounting portion of the casing is formed at a position higher than the oil level of the lubricating oil supplied into the casing, the lubricating oil with low cleanliness inside the casing is provided inside the pump body. There is no risk of inflow, and the hydraulic oil inside the pump body will always have a high degree of cleanliness, and the fluid pressure pump can be driven normally. Further, with the above configuration, if the hydraulic oil inside the fluid pressure pump leaks and flows into the casing due to a defective oil seal, the amount of lubricating oil in the casing increases. It is conceivable that an oil level cage provided at the location will detect and issue an alarm. Therefore, it is possible to detect early that the fluid pressure pump is defective, so that it is possible to provide a fail-safe mechanism for the fluid pressure pump.

According to the invention of claim 5, claim 1
From the above, the effect of claim 4 can be obtained, and the liquid-tight structure of the fluid pressure pump and the pump mounting portion can be ensured with high accuracy, and the fitting portion of the pump body can be simply fitted into the pump mounting portion. Since the liquid-tight structure is secured, the work of connecting the fluid pressure pumps can be easily performed. According to the invention of claim 6, the effects of claims 1 to 5 can be obtained, the liquid tightness of the working fluid inside the pump body can be maintained with high accuracy, and the inside of the casing can be cleaned. There is no possibility that lubricating oil having a low degree of inflow will flow into the pump body, and the fluid pressure pump can be driven normally.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a four-wheel drive vehicle of the present invention.

FIG. 2 is a characteristic diagram showing discharge flow rate characteristics of a fluid pressure pump and a fluid pressure motor according to the present invention.

FIG. 3 is a diagram showing the structure of a transaxle according to the present invention.

FIG. 4 is a view showing a III-III line arrow in FIG. 3 and a state of being mounted in an engine room.

[5] FIG. 4 shows the A-P ₂ -A' view taken along line in a diagram showing a state of further connecting the fluid pressure Pon.

FIG. 6 is an enlarged view showing a connected state of a pump mounting portion formed on a casing and a fitting portion formed on a fluid pressure pump.

[Explanation of symbols]

 1 Main Motor 2 Transmission 3b Final Gear 4 Front Axle (Drive Axle) 6 Fluid Pressure Pump 6a Pump Drive Shaft 6b Drive Gear 6c Pump Main Body 6d Sleeve 6f Housing Mounting Part (Fitting Part) 6g, 6p Ring Groove 6h, 6m Oil Seal Member 6j Ring member 6k Adjust shim 8H, 8L Flow path 10 Fluid pressure motor 18 Rear axle (driven axle) 20a Converter casing (casing) 22a Transfer casing (casing) 24b Input shaft 34d Pump mounting part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroo Kitada 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd.

Claims (6)

[Claims] 1. A drive axle to which a drive force is transmitted from a main prime mover via a transmission, a fluid pressure pump which discharges a working fluid by transmitting the drive force from the main prime mover side, and a drive axle which rotates in conjunction with the driven axle. A four-wheel drive vehicle including a fluid pressure motor and a flow path that communicates between the fluid pressure pump and one of the discharge port and the other suction port of the fluid pressure motor, wherein the casing of the transmission is the casing. While forming a pump mounting portion that opens toward the final gear of the transmission disposed inside,
The fluid pressure pump has a structure in which a pump drive shaft protrudes from a pump body and a drive gear is coaxially connected to the pump drive shaft, and the pump drive shaft inserted into the casing from the pump mounting portion is connected to the drive gear. A four-wheel drive vehicle in which the fluid pressure pump is attached to the casing in a state of being meshed with the final gear via the pump main body and externally attached to the outer peripheral portion of the pump mounting portion. 2. A driving force from the main prime mover is disposed in the engine room in a laterally installed manner, and the main prime mover is provided in the casing of the transmission arranged on one side in the vehicle width direction with respect to the main prime mover. Is transmitted from the input shaft and the final gear to which the driving force is transmitted from the input shaft via another transmission shaft and a transmission gear, while their axes are separated from each other in parallel to the front-rear direction of the vehicle. It is arranged so as to extend in the width direction, and when an arbitrary plane including the axis of the input shaft and the final gear is used as a reference plane, the axis of the pump drive shaft is positioned above the reference plane and the vehicle width is set. The four-wheel drive vehicle according to claim 1, wherein the fluid pressure pump is attached to the casing so as to extend in a direction. 3. The pump mounting portion of the casing,
3. The pump main body, which is formed at a predetermined position of the casing that does not face the main prime mover and is externally attached to an outer edge portion of the pump mounting portion, is arranged apart from the main prime mover. Four-wheel drive vehicle. 4. The pump mounting portion of the casing,
The four-wheel drive vehicle according to any one of claims 1 to 3, characterized in that the four-wheel drive vehicle is formed at a position above the oil level of the lubricating oil supplied into the casing. 5. A fitting portion that fits into the pump mounting portion is formed in the pump body, and a ring groove is formed in a circumferential direction of either the outer circumference of the fitting portion or the inner circumference of the pump mounting portion. The four-wheel drive vehicle according to any one of claims 1 to 4, wherein a ring-shaped oil seal member is mounted in the ring groove. 6. A ring-shaped oil seal member for maintaining liquid tightness of the pump main body is attached to the outer periphery of the pump drive shaft on the proximal end side, according to any one of claims 1 to 5. Four-wheeled vehicle.