JPH0463260B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention provides lubrication for a transfer device that switches between two and four-wheel drive in a part-time four-wheel drive vehicle that normally drives two-wheel drive using one of the front and rear wheels, but uses four-wheel drive when necessary. Regarding the mechanism,
In particular, the sliding part between the transfer driven gear on the drive side and the rear drive shaft on the driven side, which is rotatably fitted therein and integrally connected by the action of the transfer clutch, is forced during four-wheel drive. Concerning things that lubricate.

[Conventional technology and issues]

The part-time four-wheel drive vehicle proposed by the applicant is configured to transmit power directly to either the front or rear wheels from a transmission, and the transmission switches between two and four-wheel drive. Power is also transmitted to the front and rear wheels via a transfer device. In the transfer device, a transfer driven gear, which is constantly rotated by power from the transmission, is rotatably fitted to the rear drive shaft, and a hydraulic clutch type transfer clutch is connected between these gears and the rear drive shaft. is provided, and the gear is integrally connected to the rear drive shaft by the action of this clutch to transmit power, thereby providing four-wheel drive. Therefore, the action of the transfer clutch was solved 2
In the case of wheel drive, the rear drive shaft is in a free state relative to the transfer driven gear, but this rear drive shaft is turned in the opposite direction from the road surface, and in the end, the rear drive shaft always rotates regardless of whether it is 2 or 4 wheel drive. Therefore, when traveling substantially straight on a dry road surface, the transfer driven gear and the rear drive shaft rotate at a constant speed, and there is no relative rotation between them. However, when the drive wheels slip in 2-wheel drive, or when turning a tight corner in 4-wheel drive, the front
Differences in the turning radius of the rear wheels generate torsional torque (internal circulation torque) in the drive system, and in this case, when changing the clutch torque of the transfer clutch to cause it to slip, there is a relative difference between the transfer driven gear and the rear drive shaft. Causes rotation. Here, 2
When the transfer clutch is disengaged, such as when driving wheels, the surface pressure on the sliding parts of the driven gear and rear drive shaft is almost zero, so the only lubrication is oil droplets from the rotation of the transfer drive gear. That's enough. By the way, during four-wheel drive due to the action of the transfer clutch, the surface pressure on the sliding parts increases, so it is necessary to forcibly lubricate the sliding parts between the driven gear and the drive shaft against their relative rotation. As a prior art similar to the present invention, there is, for example, Japanese Utility Model Publication No. 54-17747, which uniformly lubricates a plurality of gears fitted to a rotating shaft, and the relationship between these rotating shafts and gears is The assumption is that there is always relative rotation between them. On the other hand, the present invention deals with the case where there is no normal relative rotation but relative rotation occurs during four-wheel drive, and the technical idea is completely different in this respect. In view of these circumstances, the present invention takes advantage of the fact that the hydraulic transfer clutch is supplied with oil during four-wheel drive, and uses the oil in this case to control the sliding part between the transfer driven gear and the rear drive shaft. It is an object of the present invention to provide a transfer device lubrication mechanism for a four-wheel drive vehicle that is capable of forcibly lubricating and sufficiently coping with relative rotation during tight corner turning.

[Means to solve the problem]

In order to achieve its purpose, the transfer device lubrication mechanism of the present invention directly transmits power to one of the front and rear wheels, and also transmits power to the other of the front and rear wheels via the transfer device as necessary. The transfer device is configured such that a transfer driven gear on the drive side is rotatably fitted to a rear drive shaft on the driven side, and a hydraulic clutch is provided between the rear drive shaft and the transfer driven gear. In a 4-wheel drive vehicle that is equipped with a transfer clutch for switching 4-wheel drive, and an oil passage for supplying oil to the piston chamber of the clutch is formed on the rear drive shaft, the oil pump and the an oil passage connecting the oil passage; a switching valve for two-wheel or four-wheel drive operation provided in the middle of the oil passage;
The sliding part between the transfer driven gear and the rear drive shaft is provided with an oil hole for branching and supplying lubricating oil from the oil passage, and the switching valve switches for four-wheel drive operation. When the oil pump is turned on, sliding oil is forcibly circulated from the oil pump to the sliding portion through the oil passage and the oil hole.

【Example】

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. First, to explain the transmission system of an example of a four-wheel drive vehicle to which the present invention is applied in FIG. The turbine shaft 3 is connected to the automatic transmission 4 and transmitted through the turbine shaft 3 . automatic transmission 4
Clutches 6 and 7 selectively input the power of the planetary gear 5 and the turbine shaft 3 to the input element of the gear 5.
and a one-way clutch 8 for selectively locking each element of the gear 5, a brake 9, and a brake band 10, and the shifted power from the automatic transmission 4 is taken out forward by an output shaft 11.
Reduction drive and driven gear 12,1
It is connected to 3. Further, a front wheel final reduction device 14 is arranged in the lower part between the torque converter 2 and the automatic transmission 4, and a drive pinion 17 formed on one side of the shaft 16 of the gear 13 is attached to the crown gear 15 of this device 14. By meshing, two-wheel drive driving is achieved using the front wheels. The other side of the drive pinion 17 is extended rearward by a transfer drive shaft 18 and is connected to a transfer device 19 mounted at the rear of the automatic transmission 4.
transfer drive and driven gear 20,
Connect to 21. This gear 21 is connected to a rear drive shaft 23 via a transfer clutch 22 consisting of a hydraulic clutch for switching two and four wheel drives, and further from the rear drive shaft 23 to a propeller shaft 22.
4 to the rear wheel final reduction gear 25. Next, the structure of the transfer device 19 will be described in detail with reference to FIG. 2. First, an extension case 28 is joined to the rear end of the transmission case 26 having the automatic transmission 4 via a plate-shaped partition 27. A transfer drive gear 20 is provided in the case 28 and is integrally attached to the rear end of the transfer drive shaft 18, and is pivoted at the hub of the gear 20 by the partition 27 and bearings 29, 30 on the case 28 side. be supported. Also case 2
A rear drive shaft 23 is installed parallel to the top of the transfer drive shaft 18 in the
A transfer driven gear whose front end fits into the partition 27 and is pivotally supported by a bearing 31, whose middle part is pivoted by a bearing 32 on the case 28 side, and which meshes with the transfer drive gear 20 on the rear drive shaft 23. 21 are rotatably fitted, and a washer 33 is sandwiched between the gear 21 and the bearing 31. Furthermore, a hub 34 of a hydraulic clutch type transfer clutch 22 is attached to the transfer driven gear 21, and a drum 35 is spline-fitted to the rear drive shaft 23. A clutch plate 39 interposed between the hub 34 and the drum 35 is pressed into contact with the hub 34 and the drum 35 through the hub 38 and the like to integrally connect the hub 34 and the drum 35. As a control system for the transfer clutch 22, an oil passage 41 from the oil pump 40 in the automatic transmission 4 is formed in the partition body 27.
and communicates with the piston chamber 36 via an oil passage 43 within the rear drive shaft 23. A solenoid valve 44 is provided in the oil passage 41, and this valve 4
4 is adapted to be switched in response to a signal from a switch 45 for operating two- and four-wheel drive. In such a configuration, in order to lubricate the sliding portion 46 between the transfer driven gear 21 and the rear drive shaft 23 using the oil supplied to the clutch 22, the oil is supplied from the oil passage 43 within the rear drive shaft 23. An oil hole 4 is located approximately in the middle of the sliding portion 46.
7 is drilled. In this hydraulic circuit, if the hydraulic pressure of the clutch 22 is temporarily lowered by detecting the steering angle when turning a tight corner, the pressing force of the clutch plate 39 is reduced, causing slippage, and it is possible to absorb torsional torque. be. Since the present invention is configured in this way, 2.
When the four-wheel drive operation switch 45 is turned off and the solenoid valve 44 is switched to the drain side,
The piston chamber 36 of the transfer clutch 22 is drained and the clutch plate 39 is released. As a result, the connection between the transfer driven gear 21 and the rear drive shaft 23 is disconnected, and power is no longer transmitted to gears 21 and beyond, and as a result, the power from the automatic transmission 4 is transmitted only to the front wheels by the front wheel final reduction device 14. , the vehicle will run in two-wheel drive. In this case, by draining the oil through the oil hole 47 together with the oil passage 43, the oil splashed by the rotation of the transfer drive gear 20 is removed from the washers 33 on the sliding portion 46 between the transfer driven gear 21 and the rear drive shaft 23. The lubricant is simply supplied through the grooves, etc. On the other hand, when driving uphill, on rough roads, on snowy roads, etc., the switch 45 is turned on to increase tire grip.
When the solenoid valve 44 is switched to communicate the oil pump 40 to the clutch 22 side by turning on the
Oil is supplied from the oil pump 40 to the piston chamber 36 of the transfer clutch 22 through oil passages 41 to 43, and the clutch plate 39 is brought into pressure contact with the piston chamber 36 by the piston 37. Therefore, the transfer driven gear 21 is connected to the rear drive shaft 23.
The power from the automatic transmission 4 is connected to the gear 21, the rear drive shaft 23, and the propeller shaft 2.
4. The signal is also transmitted to the rear wheels via the rear wheel final reduction gear 25, resulting in four-wheel drive driving. In this case, the clutch 22 is connected to the oil passage 43.
Since an oil hole 47 is provided in front of the piston chamber 36, the oil hole 47 is provided in front of the piston chamber 36.
6, oil for the clutch is supplied from the oil hole 47 to the sliding portion 46 between the driven gear 21 and the rear drive shaft 23. Therefore, the above-mentioned piston chamber 3
When four-wheel drive is performed by refueling 6, the sliding portion 46 is already forcibly lubricated in the process of becoming four-wheel drive. Therefore, when switching to four-wheel drive from a state in which the drive wheels slip and relative rotation occurs between the driven gear 21 and the rear drive shaft 23 during two-wheel drive, the surface pressure suddenly increases and the relative rotation occurs. By causing this, it is possible to perform lubrication that is suitable for specific lubrication requirements. In addition, when the clutch torque is high and the surface pressure of the sliding part 46 is high during four-wheel drive, high oil pressure lubrication is always performed there, so when turning in a tight corner, the turning radius of the front and rear wheels When a relative rotation occurs between the driven gear 21 and the rear drive shaft 23 due to a difference between Sufficient lubrication is provided.

【Effect of the invention】

As is clear from the above description, according to the present invention, in the transfer device 19 that switches between two and four-wheel drive of a part-time four-wheel drive vehicle, Hydraulic clutch type throttle clutch 2
2, the sliding part 46 with the rear drive shaft 23, which is integrally connected, is forcibly lubricated in accordance with the relative rotation between the two, and this also occurs as the surface pressure on the sliding part 46 increases during four-wheel drive. Since the lubricating oil pressure supplied to the oil hole 47 also increases, smooth rotation is ensured and seizure etc. are prevented. Since the hydraulic clutch type transfer clutch 22 is supplied with oil, there is no need to provide a special lubrication system and the structure is simple. Since forced lubrication is performed in advance when switching from two-wheel drive to four-wheel drive, the above-mentioned lubrication effect is fully exhibited. Furthermore, since the hub 34 of the clutch 22 is attached to the transfer driven gear 21,
A part of the oil used for lubrication between the clutch plate 39 and the rear drive shaft 23 can be supplied to the clutch plate 39 side by centrifugal force to lubricate the clutch plate 39 side.

[Brief explanation of drawings]

FIG. 1 is a skeleton diagram showing an example of a four-wheel drive vehicle to which the present invention is applied, and FIG. 2 is a configuration diagram showing an embodiment of the mechanism of the present invention. 4... Automatic transmission, 14... Front wheel final reduction gear,
19...Transfer device, 21...Transfer driven gear, 22...Transfer clutch,
23... Rear drive shaft, 25... Rear wheel final reduction gear, 36... Piston chamber, 43... Oil passage, 46...
...Sliding part, 47...Oil hole.

Claims (1)

[Scope of Claims] 1. A power transmission is configured such that power is directly transmitted to one of the front and rear wheels, and power is also transmitted to the other of the front and rear wheels via a transfer device if necessary. In this device, a transfer driven gear on the drive side is rotatably fitted to a rear drive shaft on the driven side, and a hydraulic clutch type transfer drive for switching between 2 and 4 wheel drive is connected between the rear drive shaft and the transfer driven gear. There is an accretion,
Further, in a four-wheel drive vehicle in which an oil passage for supplying oil to the piston chamber of the clutch is formed in the rear drive shaft, oil passages 41 and 42 connecting the oil pump 40 and an oil passage 43 in the rear drive shaft 23, and Oil road 4
A switching valve 44 for two-wheel or four-wheel drive operation provided midway between the two wheels 1 and 42 and a sliding portion 46 between the transfer driven gear 21 and the rear drive shaft 23 are supplied with oil from the oil passage 43 for lubrication. When the switching valve 44 is switched to four-wheel drive operation, the oil passages 41, 42, 4 are connected from the oil pump 40 to the oil passages 41, 42, 4.
3. A transfer device lubrication mechanism for a four-wheel drive vehicle, characterized in that sliding oil is forcedly circulated to the sliding portion 46 through the oil hole 47.