JPS6280354A - Power transmission device for 4w-drive car - Google Patents

Abstract

PURPOSE:To facilitate the slip control and obtain the compact structure by pressing-operating a wet type multidisc clutch installed onto a ring gear mount case by a hydraulic actuator, in a power transmission device for a 4W-drive car based on F.F. CONSTITUTION:A wet type multidisc clutch 50 is arranged onto a ring gear mount case 25 which covers a differential gear 5 for front wheels and is coaxially arranged to the differential gear 5. Said clutch 50 is pressing-operated by a hydraulic actuator 54 having a plurality of pistons 55 and 56 arranged in series. Further, a hydraulic pressure is supplied through the individual oil passages 57, a, b, and c, and 59, d, e, and f, into the oil chambers 60 and 61 individually formed by a plurality of pistons 55 and 56. Further, the captioned device can be applied to a power transmission device for a 4W-drive car in part time system and a power transmission device for 4W-drive car in full time system which is equipped with a center differential gear 33 in a transfer part 7. In this case the clutch 50 constitutes an operation restricting device 6 for the differential operation of the center differential gear 33.

Description

Detailed Description of the Invention (a) Industrial Application The present invention is a power transmission device for a four-wheel drive vehicle, particularly a power transmission device for a four-wheel drive vehicle based on F/F (front engine/front drive). It concerns a transmission device. There are two types of power transmission systems for 4-wheel drive vehicles: a full-time system that transmits rotation to the front and rear wheels at all times, and a full-time system that transmits rotation only to the front wheels (or rear wheels) during normal times and 4-wheel drive only when necessary. However, the present invention relates to a structure of a power transmission device that can be applied to both of these types.

(B) Prior Art Conventionally, a device for making a power transmission device for a four-wheel drive vehicle by making slight changes to the power transmission device for a front-wheel drive vehicle with a pre-tank engine has been disclosed, for example, in Japanese Patent Laid-Open No. 18656/1983. and has been proposed in Japanese Patent Application Laid-open No. 1030/1983.

In general, full-time four-wheel drive vehicles prevent the phenomenon of so-called tight corner braking, in which braking occurs due to the difference in rotational speed between the front and rear axles when making a sharp turn at low speed on a road surface with a high coefficient of friction. Therefore, a central differential is essential, but due to the installation of the central differential, if one wheel of a four-wheel drive vehicle becomes unloaded, torque cannot be transmitted due to the operation of the differential. Therefore, it is necessary to provide a differential limiting mechanism that stops or limits the operation of the differential device. Conventionally, the differential limiting mechanism consists of a sleeve that engages and disengages the right side gear and the pinion shaft, and the sleeve is slidably supported by a spline on the shaft of the side gear, and the tip of the sleeve is The operation of the central differential device 33 is switched by engaging and disengaging the pinion shaft like a dog clutch (Japanese Patent Application Laid-Open No. 1983-1999-
(See Publication No. 18656).

In addition, for part-time 4-wheel drive vehicles,
A clutch is installed in a transfer section that transmits power to the rear wheels to connect and disconnect power, and the clutch switches between a front-wheel drive state and a four-wheel drive state. And conventionally,
The front wheel/four wheel switching round clutch is composed of a wet multi-plate clutch (see Japanese Patent Laid-Open No. 1030/1983).

←→ Problems to be Solved by the Invention However, in mechanical clutches such as dog clutches, like the differential limiting mechanism in the above-mentioned full-time system, there is a large rotational difference between the components of the central differential gear for sharp turns. If there is Clutches cannot be operated arbitrarily and instantaneously, and are difficult to operate.

In addition, using a wet multi-disc clutch like the clutch for switching between 2 and 4 wheels in the part-time system described above solves the problem of operability, but it also allows the necessary torque capacity to be transmitted within a limited space. The latch is difficult to install and causes problems with torque transmission capacity. Furthermore, since conventional wet multi-disc clutches are suppressed by a single-acting hydraulic actuator, it is difficult to control slippage by 1"T, making it difficult to perform appropriate four-wheel drive control according to road conditions. Can not.

Therefore, the present invention solves the above-mentioned problems by using a wet multi-disc clutch, but having a compact structure, sufficient torque capacity, and easy slip control. The object of the present invention is to provide a power transmission device for a four-wheel drive vehicle.

(b) Means for Solving the Problem The present invention has been made in view of the above circumstances, and is a four-wheel vehicle comprising an automatic transmission mechanism section 3, a front wheel differential device 5, 5', and a transfer section 7. In the drive vehicle power transmission device 1 (FIG. 2 or 4), as shown in FIG. 1, a ring gear mount case covers the front wheel differential device 5 and is arranged coaxially with the differential device. A wet type multi-disc clutch 50 is disposed at 25. The wet multi-disc clutch 50 is configured to be pressed and operated by a hydraulic actuator 54 formed by a plurality of pistons 55, 56 installed in series, and is further configured to be operated by a hydraulic actuator 54 formed separately by the plurality of pistons 55, 56. Separate oil passages 57. a, b, c
and 59. It is characterized in that it is configured to supply hydraulic pressure via d, e, and f.

Note that, as shown in FIGS. 2 and 3, the above-described configuration can be applied to a full-time power transmission device 1 for a four-wheel drive vehicle having a central differential device 33 in the transfer section 7. The plate clutch 50 constitutes a differential limiting device 6 that stops or limits differential operation of the central differential device 33.

Further, as shown in FIG. 4, the above-mentioned configuration can be applied to a part-time type power transmission device 1' for a four-wheel drive vehicle, which consists of a power transmission device in which the transfer portion 7' is directly connected to the rear wheel side. The multi-plate clutches 5 and 0 in this case constitute a rear wheel operation switching section 6' that connects and disconnects power transmission between the ring gear mount case 25' and the transfer section 7'.

(E) Function Based on the above configuration, in the case of the full-time system, as shown in FIG. 41 is branched from a pinion 46 on the differential carrier 41 to one side gear 42 connected to the front wheel differential 5 and the other side gear 43 connected to the rear wheels. The driving force transmitted to the one side gear 42 is transmitted to the front wheel differential 5, where the left and right side gears 27, 2
Rotate each front axle 30, 31ie to drive the front wheels. Further, the driving force transmitted to the other side gear 43 is transmitted to the other side gear 43.
The signal is transmitted to the gear 40 through the ring gear mount case 32 directly connected to the rear wheel drive ring gear 35, and further transmitted to the respective rear axles via the drive pinion shaft 39 and the like to drive the rear wheels.

During normal driving, the wet multi-disc clutch 50 is disengaged and the central differential device 33 is maintained in the operating state, and the central differential gear 33 is maintained in the operating state, and the differential is applied to the front axle and the rear axle, respectively. The clutch 50 is engaged when the tires slip due to snowy or frozen roads, or when there is a risk of slipping. Then, the mount case 25 and the front wheel differential device 5
The two elements 41 and 42 of the central differential device 33, which are connected to the mount case and the differential carrier, respectively, are integrated, and the operation of the central differential device 33 is stopped. .

In this state, the rotation of the ring gear mount case 25 is directly transmitted to the front wheel differential device 5 via the wet multi-disc clutch 50, and transmitted to the left and right front axles 30, 31, as well as the central differential value that rotates together. The rotation is transmitted to the rear wheel ring gear 35 via M33, and the rotation at the same speed as the front axle is transmitted to the left and right rear axles.

On the other hand, in the case of part-time system, as shown in Figure 4,
The rotation of the output gear 20 of the automatic transmission mechanism 3 is transmitted to the mount case 25' via the ring gear 21', and is further transmitted to the differential carrier 26 of the front wheel differential 5' which is integrally formed with the case 25'. ', and is distributed and transmitted to the left and right front axles 30, 31 by the differential gear 5'. Furthermore, when the wet multi-disc clutch 50 that constitutes the rear wheel operation switching section 6' is connected, the mount case 25'
The rotation C is transmitted to the rear wheel drive ring gear mount case 32' via the hollow shaft 45', and further transmitted to the rear axle via the ring gear 35, gear 40, etc.

A wet multi-disc clutch 50 (in this case, the oil passage 5
7. When hydraulic pressure is supplied to only one oil chamber 60 through a, b, and c, the first piston 55 presses the second piston 56 through the collar 56a. Then, the wet multi-disc clutch 50 is engaged with a relatively weak pressing force, and slip control is performed.

Therefore, in this state, if a torque difference of more than a predetermined value acts on the front and rear wheels, the clutch 50 will slip, and the torque will be carried by the central differential device 33 in the full-time system, or released in the part-time system, and transferred to the front wheels. , allow for differences in rear wheel rotation. This prevents tight corner braking during coordinating while transmitting a predetermined torque to the front and rear wheels. In addition to supplying hydraulic pressure to the oil chamber 60 mentioned above,
When hydraulic pressure is supplied to the other oil chambers 61 through the oil passages 59, d, a, and f, in addition to the pressing force exerted by the first piston 55, a force acting on the second piston 56 is exerted between it and the reaction force plate 53. A pressing force due to the hydraulic pressure in the oil chamber 61 acts. In this state,
The wet multi-disc clutch 50 is engaged with a relatively strong pressing force,
The clutch 50 hardly slips, and rotation at the same speed is transmitted to the front and rear wheels.

(F) Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

As shown in FIG. 2, a full-time transverse front engine power transmission device 1 for a four-wheel drive vehicle includes a torque converter section 2, an automatic transmission mechanism section 3, a front wheel differential device 5, and a differential limiting mechanism. 6 and a transfer part 7, and these are joined together: a transaxle housing 9;
It is housed in a transaxle case 10 and a transfer case 12. The torque converter section 2 includes a torque converter 13 and a lock-up clutch 1.
5, and the rotation of the engine output shaft 16 is transmitted to the input shaft 17 through these. The automatic transmission mechanism section 3 is composed of a three-stage planetary gear unit that is appropriately controlled by a clutch and a brake, and the rotation of the input shaft 17 is controlled via these gear units to 1st speed, 2nd speed, 3rd speed, overdrive, and reverse. The shaft 19 is shifted to each gear position as appropriate.
The signal is transmitted to the output gear 20, which is rotatably supported.

Further, as shown in detail in FIG. 3, the front wheel differential device 5 is
A first ring gear 21 meshing with the gear 20 is fixed, and conical roller bearings 22 and 2 are mounted on each of the cases 10 and 9.
The front differential carrier 26 is disposed coaxially within a mount case 25 supported via brackets 3 and has a front differential carrier 26 rotatably supported within the mount case 25.

Furthermore, a pinion shaft 28a supporting a pinion 28 extends vertically and is rotatably supported on the differential carrier 26, and left and right side gears 27.degree. 29 extend horizontally and are rotatably supported. Each side gear 27, 29 has a front axle 30, 31, respectively.
are connected to each other so that power can be transmitted. In addition, the first ring gear mount case 25 and the front wheel differential device 5
A transfer case 12 that can be divided into left and right halves is installed on the right side of the engine, that is, behind the engine, and a first ring gear mount case 25 and a front wheel differential 5 are installed coaxially within this transfer case 12. A transfer section 7 is configured. The transfer section 7
has a second ring gear mount case 32, which can be divided into left and right halves, integrally supports a second ring gear 35 for rear wheel drive, and transfer case 12. is rotatably supported via a pair of conical roller bearings 36 and 37.

A gear 40 of a drive pinion shaft 39 is always engaged with the second ring gear 35, and the drive pinion shaft 39 is connected to the rear axle via a known propeller shaft and rear wheel differential (not shown). Connected to enable power transmission. A central differential device 33 is disposed within the second ring gear mount case 32, and the central differential device 33 is sandwiched between the inside of the second ring gear mount case 32 and the outside of the left side gear 42. The differential carrier 41 has a cantilever structure and is supported by the vehicle. Furthermore, the rotation of the first ring gear mount case 25 is transmitted to the differential carrier 41 via the first hollow shaft 45.
Further, the differential carrier 41 supports a pinion shaft 46a. Further, the second ring gear mount case 32 and the right side gear 43 are directly connected by spline, and the differential pinion 46 attached to the pinion shaft 46a is meshed with the left and right side gears 42 and 43, respectively. The right front axle 31 passes through the insides of both side gears 42 and 43, and the transfer case 1
It protrudes to the right from the right end of 2. Also,
The left side gear 42 of the center differential value N33 is spline-coupled to the left end of the side gear 42 and is rotatably mounted on the front axle 31. differential carrier 2
6 so that power can be transmitted.

The differential limiting mechanism 6, as shown in detail in FIG.
It is disposed within a first ring gear mount case 25 that is provided so as to cover the front wheel differential device 5 and coaxially with the device M5, and is comprised of a wet friction multi-plate clutch 50. The clutch 50 has an outer friction plate 51 mounted on the mount case 25.
The friction plates 52 are connected to the differential carrier 26, and the friction plates 52 are connected to the first and second pistons 55 and 56, which are housed in a cylinder formed by the mount case 25. Operated by pressure. Also,
Inside the syringe are a first piston 55 and a second piston 56.
A reaction plate 53 is arranged in an oil-tight manner between these pistons, and the first piston 55 is in contact with the outer peripheral flange 56a of the second piston 56, and the second piston 56 is in contact with the reaction plate 5.
A hydraulic actuator 54 consisting of a double piston is configured in contact with the side surface of 3. Further, oil holes 57 and 59 are formed at different angular positions in the portion of the transfer case 12 facing the transaxle housing 9, and the first oil hole 57 is connected to the annular groove a formed in the first hollow shaft 45. The second oil hole 59 communicates with the oil chamber 60 acting on the first piston 55 through the oil grooves d and e.

It communicates with an oil chamber 61 that acts on the second piston 56 through f.

Next, the operation based on the above-mentioned structure will be explained.

The rotation of the engine is transmitted to the automatic transmission mechanism 3 via the torque converter 13 or the 1F lockup clutch 15, and is appropriately changed in speed by the transmission mechanism 3 and output to the output gear 20, and then to the first ring gear 21. is transmitted to the first mount case 25 via. During normal running, no oil pressure is supplied to the oil chambers 60, 61, and the wet multi-disc clutch 50 is in a disengaged state. In this state, the rotation of the first mount case 25 is transmitted to the differential carrier 41 of the central differential device 33 via the first hollow shaft 45, and further branched and transmitted from the differential pinion 46 to the left and right side gears 42, 43. .

The rotation of the left side gear 42 is controlled by the second hollow shaft 4.
7 to the differential carrier 26 of the front wheel differential 5, and further from the differential pinion 28 to the left and right side gears 27.
, 29 and are transmitted to the left and right front axles 30, 31, respectively. On the other hand, the rotation of the right side gear 43 is transmitted to the second mount case 32 which is spline connected to the right side gear, and further to the rear wheel drive ring gear 35.
It is transmitted to the drive pinion shaft 39 via the gear 40, and then to both left and right rear axles via a propeller shaft and a rear differential (not shown).

In addition, when there is a risk of tire slipping on snowy roads, frozen roads, etc., or when a wheel gets stuck in a groove and slips, the wet multi-disc clutch 50 is activated by supplying oil pressure from the oil chambers 6υ and 61Cζ. engage.

In this state, the rotation of the first mount case 25 is directly transmitted to the differential carrier 26 of the front wheel differential device 5 via the clutch 50, and further transmitted to the left and right front axles 30, 31 via the front wheel differential device 5. transmitted to. At the same time, the differential carrier 41 and left side gear 42 of the central differential device 33, which are integrated with the first mount case 25 and the differential carrier 26 through the hollow shirts 1-45 and 47, do not differentially move. They are rotated together, and the rotation is further transmitted to the second mount case 32. As a result, rotation at the same speed as the front wheel drive differential carrier 26 is transmitted to the rear wheel drive ring gear 35, thereby driving the left and right rear axles.

At this time, the operation of the first piston 55 and the second piston 56 can be switched depending on the road surface condition. For example, when it is better to allow a certain degree of rotational difference between the front and rear wheels when driving on a snowy road, hydraulic pressure is supplied only to the oil chamber 60 via the oil hole 57 and oil grooves a, b, and c. Then, the first piston 55 presses the flange 56a of the second piston 56 and engages the wet multi-disc clutch 50 with a relatively small pressing force. In this state, if a torque difference of more than a predetermined value occurs between the front and rear wheels, the wet multi-disc clutch 5
0 slips, the torque is carried by the central differential bag FI33, and even when cornering, tight corner braking phenomenon and tire slip caused by rotation difference are prevented, while
To surely transmit a predetermined torque to front and rear wheels even if slip occurs in any one of the wheels. In addition, when either the front or rear wheel gets stuck in a groove, in addition to supplying hydraulic pressure to the oil chamber 60, hydraulic pressure is also supplied to the oil chamber 61 through the oil hole 59 and oil grooves d, e, and f. do. Then, in addition to the pressing force of the first piston 55, the oil chamber 6 between the second piston 56 and the reaction plate 53 is applied to the second piston 56.
1 also acts, and the wet multi-disc clutch 50 is engaged with a relatively large pressing force.

In this state, the clutch 50 hardly slips,
Rotation at the same speed is transmitted to the front and rear wheels, preventing a state in which transmission is impossible due to idling and allowing the wheels to escape from the groove.

Next, an embodiment in which the present invention is applied to a power transmission device for a part-time four-wheel drive vehicle will be described.

As shown in FIG. 4, the part-time tank front engine power transmission system 1' for a four-wheel drive vehicle includes a torque converter section 2, an automatic transmission mechanism section 3, a front wheel differential device 5', and a rear wheel operation switching device. 9, comprising a section 6' and a transfer section 7'.
, and a transaxle housing 9 and a transaxle case 10, which are joined to each other. and is housed in a transfer case 11. The torque converter section 2 and automatic transmission mechanism section 3 are completely the same as the full-time type power transmission device 1 described above. Further, the front wheel differential device 5' is disposed in a first ring gear mount case 25 that fixes a ring gear 21 meshing with the output gear 20 of the automatic transmission mechanism section 3, and is integrated with the mount case 25. Front differential carrier 2 fixed to
6, and the rotation of the ring gear 21 differentially rotates the left and right front axles 30, 31 via the differential bag M5.

Further, the rear wheel operation switching section 6' consists of a wet multi-plate clutch 50 fixed to the mount case 25 together with the differential carrier 26, and the clutch 50 is a double piston clutch similar to the clutch of the differential limiting device described above. It is controlled by a hydraulic actuator 54 consisting of 55 and 56, and
The output portion 53a is connected to a hollow shaft 45' fitted into the right front axle 31. Further, the transfer section 7' is connected to the transfer case 12. and a second ring gear mount case 3-2' that fixes the hypoid ring gear 35 and is spline-coupled to the tip of the hollow shaft 45', and the mount case 32' is mounted by roller bearings 36 and 37. It is rotatably supported by the transfer case 12. Furthermore, the gear 35 meshes with a hypoid gear 40 fixed to the tip of a drive pinion shaft 39 extending rearward, and rotation of the hollow shaft 45' is transmitted to the drive pinion shaft 39 via the hollow gears 35 and 40. be done.

As a result, the rotation of the engine is controlled by the torque converter 13.
Alternatively, the signal is transmitted to the automatic transmission mechanism 3 via the lock-up clutch 15, and further transmitted from the output gear 20 to the left and right front axles 30, 31 via the front wheel differential 5' to drive the front wheels. On the other hand, wet multi-plate clutch 5
0 can be switched manually or automatically, and is only connected when four-wheel drive is required, such as on snowy roads. When the clutch 50 is connected, the rotation of the output gear zO of the automatic transmission mechanism 3 is transmitted to the hollow shaft 45' via the clutch 50, and further to the second ring gear mount case 32' and the eight-void gear 35.40. The rear wheels are also driven via the drive pinion shaft 39, resulting in four-wheel drive.

When traveling in four-wheel drive on a dirt road, paved road, etc., hydraulic pressure is supplied to only one oil chamber 60 to suppress the first piston 55. In this state, the wet multi-disc clutch 50 is engaged with a relatively small pressing force, and if a torque difference of more than a predetermined value occurs between the front and rear wheels, the multi-disc clutch 50 will slip.

This allows the vehicle to travel in four-wheel drive while preventing tight corner braking. Furthermore, when driving on snowy roads, muddy roads, etc., in addition to the oil pressure supplied to the oil chamber 60, the oil pressure is also supplied to the oil chamber 61.

Then, in addition to the pressing force of the first piston 55, the pressing force of the second piston 56 acts, and the wet multi-plate clutch 50 is engaged with a relatively large pressing force.

In this state, the clutch 50 hardly slips, and rotation at the same speed is transmitted to the front and rear wheels, so that even if one of the wheels slips, the vehicle can be driven reliably by the other wheel.

(g) As described in detail, according to the present invention, the wet multi-disc clutch 50 is used, which prevents jamming etc. and provides excellent operability. Since the differential gears 5 and 5' are disposed in the ring guard cases 25 and 25' which cover the differential gears and are arranged coaxially with the differential gears, the configuration can be made compact and the power transmission for F-F vehicles is possible. A power transmission device for a four-wheel drive vehicle can be obtained by only slightly changing the device, and the transfer part 7゜7
It is possible to obtain both a full-time type and a part-time type power transmission device 1, 1' by making slight changes such as replacing ``, etc.'', and it is possible to support multiple series of vehicle models without major equipment changes. be able to.

Further, the wet type multi-disc clutch 50 includes a plurality of pistons 55.
56 are installed in series, so that it is possible to obtain a large pressing force compared to the number of pistons and ensure sufficient torque capacity, despite the compact configuration. can do. Furthermore, since hydraulic pressure is supplied to the oil chambers 60 and 61 formed separately by the plurality of pistons 55 and 56 through separate oil passages, the wet multi-disc clutch 50 can be operated by a pressure regulating solenoid, a duty regulator, etc. It is possible to perform slip control without using a complicated mechanism, prevent tight corner braking, etc., and perform more appropriate four-wheel drive control according to road conditions.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing a wet multi-disc clutch portion of a power transmission device for a four-wheel drive vehicle according to the present invention, and Fig. 2 is a full-time type power transmission device for a four-wheel drive vehicle to which the present invention is applied. FIG. 3 is a cross-sectional view showing the front wheel differential, differential limiting device, and transfer section. and,
FIG. 4 is a sectional view showing a part-time type power transmission device for a four-wheel drive vehicle to which the present invention is applied. 1...Power transmission device for 4-wheel drive vehicles (full-time system)
, 1'... Power transmission device for four-wheel drive vehicle (part-time system), 3... Automatic transmission mechanism section, 5.5'...
・Front wheel differential device, 6...Differential limiting device, 6
'... Rear wheel operation switching section, 7,7'... Transfer section, 25... (first) ring gear mount case, 26... Differential carrier, 3
0.31...Front axle, 32...Rear wheel drive ring gear mount case, 33...Central differential gear, 45.45' (first) hollow shaft,
47...Second hollow shaft, 50...Wet type multi-plate clutch, 51°52...Friction material,
53...Reaction force plate, 54...Hydraulic actuator, 55..., IEI piston, 56...Second piston, 57,59. a, b. c, d, e, f... oil passage, 60, 61... oil chamber.

Claims (3)

[Claims] (1) In a power transmission device for a four-wheel drive vehicle comprising an automatic transmission mechanism section, a front wheel differential device, and a transfer section, a power transmission device that covers the front wheel differential device and is arranged coaxially with the front wheel differential device. A wet multi-disc clutch is disposed in the link gear mount case, and the wet multi-disc clutch is configured to be pressed and operated by a hydraulic actuator having a plurality of pistons installed in series, 1. A power transmission device for a four-wheel drive vehicle, characterized in that hydraulic pressure is supplied to oil chambers formed separately in the four-wheel drive vehicle through separate oil passages. (2) Claim 1, wherein the transfer section has a central differential, and the wet multi-disc clutch constitutes a differential limiting device that stops or limits differential operation of the central differential. The power transmission device for a four-wheel drive vehicle as described above. (3) The power transmission device for a four-wheel drive vehicle according to claim 1, wherein the wet multi-plate clutch constitutes a rear wheel operation switching section that connects and disconnects power transmission between the ring gear mount case and the transfer section.