JPH0811498B2 - Lubrication device for transfer gear in four-wheel drive vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention is directed to a front engine / front wheel drive (hereinafter referred to as “F / F”) for horizontal installation.
The present invention relates to a lubrication device for a transfer gear portion in a four-wheel drive based on (1), specifically, a lubrication device for a transfer gear portion in which a gear portion is housed in a sealed chamber containing lubricating oil.

(B) Conventional technology Generally, in a power transmission device for a four-wheel drive vehicle based on F / F, in both a part-time system and a full-time system, a transfer gear unit that transmits engine power to rear wheels is used. It is installed and a hypoid gear is used for the gear portion. For this reason, it is necessary to use lubricating oil to which an extreme pressure additive is added to the gear portion. Therefore, the gear portion is isolated from the transfer portion in which the same lubricating oil is used as in the automatic transmission and the like, and the sealed chamber is isolated. Need to be stored in.

Conventionally, the transfer gear portion is immersed in a lubricating oil sealed in a closed chamber and lubricated by a so-called oil bath lubrication method.

(C) Problems to be solved by the invention However, the level of lubrication enclosed in the closed chamber is
It greatly varies depending on the agitation caused by the rotation of the gear part, the traveling state and the posture of the vehicle. In particular, if an oil pump is installed in the closed chamber to lubricate the bearings of the pinion shaft extending rearward, the lubricating oil in the relatively narrow closed chamber is sucked up by the oil pump, which has an extremely large effect on the oil level. Will give.

As a result, the oil level is not stable and it is difficult to lubricate the gear part reliably and effectively by the above oil bath lubrication method. In particular, a center differential device is provided, and high speed rotation acts on the transfer gear part. In a full-time type four-wheel drive device, which is often the case, the above-mentioned poor lubrication may be noticeable. Also, in order to ensure reliable lubrication, it is necessary to increase the amount of lubricating oil enclosed to raise the oil level, but this requires not only a large amount of expensive lubricating oil containing extreme pressure additives, but also However, there is an increased risk that the lubricating oil will be blown out from the presser hole provided in the upper part of the closed chamber.

It is also considered to circulate the oil in the closed chamber with a pump to forcibly lubricate the gear part and the bearing part. However, in this case, the pump is installed outside the transfer case, and the structure becomes complicated. The conduit resistance increases.

Therefore, the present invention provides an oil pump for a transfer gear in a four-wheel drive vehicle in which an oil pump is installed in a closed chamber and a predetermined amount of lubricating oil is constantly supplied from an orifice hole to a gear meshing surface, thereby eliminating the above-mentioned problems. Is intended to be supplied.

(D) Means for Solving the Problem The present invention has been made in view of the above circumstances, and for example, as shown with reference to FIG. 1, a ring gear mount case (16) to which power is transmitted from an engine is provided. A transfer drive gear (17) is fixed, and a transfer driven gear (21) provided on a pinion shaft (20) interlocking with a rear wheel is meshed with the transfer drive gear (17), and both gear parts are sealed chambers. In the transfer gear portion of the four-wheel drive vehicle based on front engine / front wheel drive, which is housed in (D), the lubricating oil in the sealed chamber D driven by the ring gear mount case (16) is stored. Inhale the specified member (24
b) Set an oil pump (53) that lubricates ... in the closed chamber. The oil passage (d) from the oil pump (53)
To j) are communicated with an orifice hole (k) which opens toward the meshing portion (A) of the gear.

(E) Operation Based on the above configuration, the torque from the engine is transmitted to the front wheels, is transmitted to the transfer drive gear (17) via the ring gear mount case (16), and is further meshed with the gear (17). It is transmitted to the rear wheels via the driven gear (21) and the pinion shaft (20). On the other hand, the oil pump (53) is driven based on the rotation of the ring gear mount case (16), sucks the lubricating oil in the sealed chamber (D), and the bearing (24b) or the like is passed through the oil passages (d to j). Lubricate specified parts. Further, due to the drive of the oil pump (53), the oil level in the relatively narrow closed chamber (D) is significantly lowered, but the gear (1
A predetermined amount of lubricating oil is constantly supplied to the meshing surfaces of 7) and (21) from the orifice hole (k), and the gear portion is always lubricated stably regardless of the rotation speed of the gear and the posture of the vehicle.

(F) Example Hereinafter, an example of the present invention will be described with reference to the drawings.

As shown in FIG. 2, a power transmission device U for a full-time front engine front four-wheel drive vehicle of a full-time type has an input gear 1 to which power is transmitted from an engine (not shown) via a torque converter and an automatic transmission. The input gear 1 is fixed to the gear mount case 2. The mount case 2 is formed of a divided case piece, is fastened together with the input gear 1 by a bolt 12, is supported by a support case 9 by tapered roller bearings 9a and 9b, and has a front differential device 3 and The differential control device 10 is housed. Further, the front differential device 3 has a front differential case 3c rotatably supported by two needle bearings 11a and 11b in the mount case 2, and the differential case
3c supports a plurality of pinion shafts 3d supporting the pinion 3p in the vertical direction to form a carrier, and left and right side gears 3a and 3b extend in the left and right direction and are rotatably supported, and each side gear 3a , 3b are connected to left and right front axles 8l, 8r, respectively, so that power can be transmitted.

Also, on the right side of the input gear mount case 2, that is,
A transfer case 13 that can be split into two parts, left and right, is installed behind the engine.
Inside, a transfer unit 15 is mounted coaxially with the input gear mount case 2 and the front differential device 3. The transfer unit 15 has a ring gear mount case 16 and the ring gear mount case 16
The left and right can be split into two parts, which integrally support a transfer drive gear 17 for driving the rear wheel composed of a hypoid gear, and are rotatably supported on the transfer case 13 via a pair of tapered roller bearings 19, 19. Have been. And the gear 17 has a pinion shaft 20
A transfer driven gear 21 composed of a hypoid gear formed at all times is always meshed with the pinion shaft.
20 is rotatably supported by an extension case 24 extending rearward via tapered roller bearings 24a, 24b, and is transmitted to a universal joint 25 via a spline portion 20a, and a propeller shaft and a rear differential not shown. Power is connected to the left and right rear axle shafts via the device so that power can be transmitted. On the other hand, a center differential device 18 is disposed in the ring gear mount case 16, and the center differential device 18 includes a differential carrier 18c having an open end. Further, the diff carrier 18c is connected to the sleeve portion 2b extending from the input gear mount case 2, and the opposite side of the connecting boss portion 18c 'is opened to form an open end, and the open end portion and It is rotatably supported by the ring gear mount case 16 with needle bearings 23, 23 interposed in the connecting boss portion 18c '. Further, a pinion shaft 18d for supporting the pinion 18p is attached to the differential carrier 18c, the left side gear 18b is directly spline-coupled to the ring gear mount case 16, and the left side gear 18a is connected to the differential carrier. linked to the differential case 3c of the front differential 3 through a boss portion 18c 'fitted within and sleeve portion 3c which is fitted on the right front axle shafts 8r _1'.

A spline joint 22 is slidably fitted to a spline formed at the tip of the sleeve portion 2b of the input gear mount case 2, and the spline joint 22 is axially operated by an operating lever (not shown). The lock position (see the upper half of FIG. 2) that engages with the spline formed in the sleeve portion of the ring gear mount case 16 and the release position (see the lower half of FIG. 2) that does not engage the mechanism are switched. It constitutes a diff lock mechanism. Although the mechanical diff lock mechanism is normally in the released position, it can be used in an emergency such as de-wheeling as well as being able to switch to the locked position when various inspections are performed by placing a tire on a roller in a service factory or the like. .

The differential control device 10 is disposed in the input gear mount case 2 provided so as to cover the front differential device 3 and coaxially with the device 3. The differential control device 10 includes a wet friction multi-plate clutch 26 and a hydraulic actuator thereof. Consists of 27. The clutch 26 has its outer friction plate connected to the mount case 2 and its inner friction plate connected to the differential case 3c, and these friction plates are pressed and controlled by the hydraulic actuator 27. Further, the hydraulic actuator 27 is arranged in an oil-tight manner between the first piston 28 and the second piston 29, which are housed in a cylinder formed in the mount case 2 in an oil-tight manner, and between both pistons. Reaction plate 30
These pistons constitute a double piston with the first piston 28 abutting on the outer peripheral flange of the second piston 29 and the reaction force plate 30 abutting on the cylinder end face.
The transfer case 13 is provided with a valve unit 31 for the differential control device 10. The control oil pressure from the unit 31 is supplied to the first piston 28 of the hydraulic actuator 27 through a pipe 32 and oil passages 33 and 35. And the second piston 29.

A lubricating oil supply hole 39 is formed in the case 9, and the lubricating oil supplied from the supply hole 39 passes through the hole 40 formed in the sleeve portion 2b and the needle bearings 11a, 23, 23.
And the like, and is discharged from the discharge hole 41 formed in the case 13, and the lubricating oil guided to the front differential device 3 direction through the needle bearing 11a passes through the clearance a to the friction plate of the clutch 26. It is lubricated and discharged from the discharge hole 42 formed in the mount case 2. At this time, the needle bearing 11a forms an orifice by appropriately regulating the flow rate of lubricating oil by the number of needles and the like, and the amount of lubricating oil introduced in the direction of the clutch 26 is controlled to a predetermined amount. Furthermore, the hole 4 formed in the sleeve portion 3c ₁ '
3 lubricating oil introduced between b and axle shaft 8r and the sleeve portion 3c ₁ 'from being supplied to the front differential case 3c through the thrust washer, reservoir into the chamber formed in the casing C, and overflows A part of the lubricating oil lubricates the needle bearing 11b.

On the other hand, oil seals 50 and 51 are installed at both ends of the gear mount case 16, that is, outside the tapered roller bearings 19 and 19, respectively.
0,51, gear mount case 16, transfer case 1
3, a closed chamber D is defined by the extension 24 and the oil seal 54 at the tip of the case. A pump drive gear 52 is fixedly mounted on the outer peripheral surface of the gear mount case 16, and the extension case 24
An oil pump 53 and a gear 55 that drives the eccentric rotor of the pump and meshes with the gear 52 are arranged in the chamber D between the transfer case 13 and the transfer case 13. Further, a strainer 56 is disposed adjacent to the oil pump 53, sucks the extreme pressure additive-containing lubricating oil sealed in the closed chamber D from the strainer 56, and through an oil passage shown below. And supply it to a predetermined place. Transfer case
Although 13 is composed of left and right divided pieces 13a and 13b, as shown in detail in FIG. 1, oil passages d, e, f, g are formed over both case pieces 13a, 13b, and further oil passages are formed. An oil passage h is formed in the divided piece 24 ₁ of the extension case connected to g, and an oil passage i is formed orthogonal to the oil passage h. Further, an oil passage i is formed from the oil passage i toward the outside of the bearing 24b. The path j is formed. Incidentally, the tip of the oil passage h is closed by the outer case of the bearing 24a, also the oil passage i is not through the tip-to-case end and its base end is fit retaining at the other of the casing cap 24 ₂ It is closed by a lid member. Then, from the oil passage h, the transfer drive gear 17 and the driven gear 21
The orifice hole k is formed so that the lubricating oil is supplied to the tooth surface immediately before the meshing portion A of the.

 Next, the operation based on the above structure will be described.

The rotation of the engine is appropriately shifted by the automatic transmission and transmitted to the input gear mount case 2 via the input gear 1. During normal driving, the valve unit
31 is connected and the hydraulic pressure based on the line pressure is
Acting on both pistons 28 and 29 of the hydraulic actuator 27 via the oil passages 32 and the oil passages 33 and 35, the wet multi-plate clutch 26 is connected at a predetermined pressure. Therefore, in the center differential device 18, the differential carrier 18c and the right side gear 18a are coupled with each other with a predetermined coupling force, and the differential thereof is limited by the predetermined regulation force. Accordingly, when the frictional force between the road surface and the tire is smaller than the above-described regulation force, for example, on a road surface having a small friction coefficient such as a snowy road or a dirt road, the center differential device is determined based on the pressing force of the clutch 26.
18 is close to direct connection, input gear mount case 2
Is transmitted to the differential case 3c of the front differential device 3 through the friction clutch 26 and the center differential device 18 that rotates integrally, and the torque is distributed to the left and right side gears 3a and 3b through the pinion 3p to drive the left and right front wheels. At the same time, it is transmitted to the pinion shaft 20 via the ring gear 17 and the gear 21 fixed to the center differential device 18, and the rear differential device further distributes torque to drive the left and right rear wheels. Further, when the frictional force between the road surface and the tire is substantially balanced with the regulating force by the clutch 26, for example, when traveling on a paved road at a relatively high speed, the tire slip is reduced in relation to the road surface friction coefficient. The clutch 26 is pressed while sliding so as not to occur. That is, the center differential device 18 distributes the torque to the front and rear wheels while absorbing the rotation difference between the front and rear wheels in a state where the torque distribution to the front and rear wheels is biased to approach 50:50.

Further, when the steering angle is turned to a large extent at a low speed, such as when entering a garage, a difference in rotation occurs between the front wheels and the rear wheels. The engaging force of the friction clutch 26 of the differential control device 10 is also weak. Therefore, the center differential device 18 based on the rotation difference between the front wheels and the rear wheels is used.
In order to allow the relative rotation of the left and right side gears 18a and 18b, the friction clutch 26 slips, transmitting torque to the front and rear wheels while preventing the occurrence of the tight corner braking phenomenon.

When traveling at a relatively high speed on a road such as a mountain road in which sharp curves continue, the driver can operate the valve unit 31 to the off position as desired. In this state, the supply of line pressure to the hydraulic actuator 27 of the differential control device 10 is cut off, and the friction clutch 26 is released. Then, the rotation of the mount case 2 is performed by the differential carrier 18c of the center differential device 18 via the sleeve portion 2b.
To the left and right side gears 18 from the differential pinion.
It is branched and transmitted to a and 18b. Then, the rotation of the left side gear 18a is transmitted to the differential case 3c of the front differential device 3 via the sleeve portion 3c ₁ ', and further branched and transmitted from the differential pinion 3p to the left and right side gears 3a and 3b, respectively, and the left and right front axle shafts 8l. , 8r is transmitted. On the other hand, the rotation of the right side gear 18b is transmitted to the gear mount case 16 which is spline-coupled to the gear, further transmitted to the pinion shaft 20 via the rear wheel driving ring gear 17 and the gear 21, and the propeller shaft (not shown) It is transmitted to the left and right rear wheels via the rear differential device.

On the other hand, based on the rotation of the gear mount case 16, the gear 5
The oil pump 53 is driven via 2, 55, the lubricating oil in the sealed chamber D is sucked in via the strainer 56, and the pump
The oil is discharged to the outside of the bearing 24b through oil passages d, e, f, g, h, i, j adjacent to 53, and the lubricating oil is transferred through the orifice hole k to the transfer drive and driven gear 17, It is ejected toward the meshing portion A of 21. The lubricating oil discharged near the bearing 24b is
4b is lubricated, the sliding splines 20a of the drive gear 20 and the universal joint 25 are lubricated, and the bearing 24a is lubricated when returning to the pump direction. Also,
The lubricating oil passing through the orifice hole k is regulated to a substantially constant amount based on the hole diameter and the length, and a predetermined flow rate of lubricating oil is always supplied to the gear meshing portion A regardless of the pump rotation speed and therefore the traveling speed. In addition to oil bath lubrication, the drive and driven gears 17 and 21 are supplied with the above-mentioned predetermined amount of lubricating oil and are reliably lubricated.

In the above-described embodiment, the differential control device 10 is used in a constantly operating state. However, it is needless to say that the differential control device 10 may be used as a so-called differential lock mechanism which is always in a non-operating state and operates only when necessary. is there. The first piston 28 and the second piston 28 of the hydraulic actuator 27 comprising a double piston
The hydraulic pressure consisting of one system is supplied to the piston 29, and it is used as a mere booster.However, it is configured so that the hydraulic pressure individually controlled by a separate oil path is supplied to enable fine slip control. Is also good. Further, although the full-time four-wheel drive device having the center differential device has been described, the present invention is also applicable to a part-time four-wheel drive device in which a clutch is interposed in the power transmission system at the rear wheels, and has a screw coupling. It can also be applied to a four-wheel drive system.

(G) Effect of the Invention As described above, according to the present invention, the oil pump (53) is driven by the ring gear mount case (18b) located in the sealed chamber (D), and the sealed chamber (D) is driven. Since it is arranged inside, the drive system is extremely simple and the oil passage structure is also simple, the structure is simple and space can be saved, and the conduit resistance can be reduced. Furthermore,
Since the orifice hole (k) opening toward the gear meshing portion (A) is communicated with the oil passages (d to j) from the oil pump (53), the oil pump (53) has a predetermined bearing (24b) or the like. Even if the oil level is lowered by driving to lubricate the member, the vehicle posture is tilted, and the rotation speed of the oil pump is low at low speed running, the orifice hole (k)
Therefore, a predetermined amount of lubricating oil is constantly supplied to the gear meshing portion (A), and early wear due to poor lubrication can be prevented to improve the reliability of the four-wheel drive vehicle. Further, it is sufficient to seal a predetermined amount of lubricating oil in the closed chamber (D), and it is possible to prevent the lubricating oil from being blown out from the breather or the like, and by utilizing the oil pump (53) and the oil passage for lubricating the predetermined member. It is sufficient to form the orifice hole (k), and it is possible to prevent cost increase.

Also, if the transfer drive gear (17) and driven gear (21) consist of hypoid gears, the amount of expensive lubricating oil containing extreme pressure additive contained is small, and hypoid gears always require sufficient lubrication. In addition to the oil bath lubrication method from the above, direct supply to the above-mentioned meshing portion (A) can reliably prevent problems due to poor lubrication.

Further, when applied to a full-time four-wheel drive vehicle having a center differential device (18), the gears (17) and (21) may rotate at high speed due to the rear wheels rising or the like. Similarly, problems due to poor lubrication can be reliably prevented.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view showing a main part according to the present invention, and FIG. 2 is a sectional view showing a power transmission device for a four-wheel drive vehicle to which the present invention is applied. 13 …… Transfer case, 15 …… Transfer part, 16 …… Gear mount case, 17 …… Transfer drive gear, 18 …… Center differential device, 20 …… Pinion shaft, 21 …… Transfer driven gear, 24 …… Extension case , 24a, 24b,
20a ... predetermined member, 52 ... pump drive gear, 53 ... oil pump, dj ... oil passage, k ... orifice hole, A
...... Gear meshing part, D ...... closed chamber, U ...... power transmission device for four-wheel drive vehicle.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takehito Kano 10 Takane, Fujii-cho, Anjo-shi, Aichi Aisin Warner Co., Ltd.・ Warner Co., Ltd. (72) Inventor Yasushi Nakamura 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Co., Ltd. (72) Inventor Isamu Minamoto 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Co., Ltd. (72 ) Inventor Masaharu Tanaka 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Co., Ltd.

Claims (3)

[Claims] 1. A transfer drive gear is fixedly mounted on a ring gear mount case to which power is transmitted from an engine, and a transfer driven gear provided on a pinion shaft interlocking with a rear wheel is meshed with the transfer drive gear. In a transfer gear portion in a four-wheel drive vehicle based on front engine / front wheel drive, which is housed in a sealed chamber, is driven by the ring gear mount case, and sucks lubricating oil in the sealed chamber, An oil pump for lubricating a predetermined member in the closed chamber is installed in the closed chamber, and an oil passage from the oil pump is communicated with an orifice hole opening toward a meshing portion of the gear. Lubrication device for transfer gears in wheel drive vehicles. 2. A lubrication device for a transfer gear portion in a four-wheel drive vehicle according to claim 1, wherein the transfer drive gear and the driven gear are hypoid gears. 3. The four-wheel drive vehicle according to claim 1, wherein the four-wheel drive vehicle is a full-time four-wheel drive vehicle in which torque is transmitted to the ring gear mount case via a center differential device. Lubrication device for transfer gears in wheel drive vehicles.