JP2510622B2 - Lubrication device for differential control device in power transmission device for four-wheel drive vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a pre-transverse engine. The present invention relates to a lubrication device for a differential control device in a power transmission device for a four-wheel drive vehicle based on front-wheel drive (front engine. Front drive, hereinafter referred to as FF), and more specifically, covers a front differential device in an input gear mount case. And a lubrication device for the above-mentioned clutch in a differential control device including a wet friction multi-plate clutch provided coaxially with the device and its hydraulic actuator.

(B) Conventional technology Recently, various systems have been proposed for a four-wheel drive vehicle by adding a transfer unit to the power transmission device of an FF vehicle,
As an example thereof, a front differential device is housed in an input gear mount case, and a differential control device for a center differential device, which includes the wet friction multi-plate clutch and its hydraulic actuator, is housed so as to cover the device and coaxially with the device. Then, by the operation of the operation control device, the driving force of the engine transmitted from the input gear is appropriately distributed to the front wheels and the rear wheels according to the situation. Lubricating oil is supplied from the shaft center hole to the central portion of the differential device, and the lubricating oil is radiated in the radial direction by centrifugal force based on the rotation of the differential case of the differential device, and both side gears, pinions and Lubricate the washers that support the thrust of each side gear and Direct the wet friction multi-plate clutch by the lubricating oil ejected from the discharge hole formed in the peripheral surface of the differential case lubricates and is drained to the outside from the discharge holes formed in the peripheral surface of the input gear mount casing.

(C) Problems to be Solved by the Invention However, in the above-mentioned clutch lubrication system, it is necessary to form a hole for lubricating oil in the shaft and a special lubricating path communicating with the lubricating oil hole is required. , The structure becomes complicated. In addition, the amount of lubricating oil supplied to the clutch varies greatly depending on the rotation condition of the front differential device, the traveling condition of the vehicle, etc. When the clutch is slipped due to the tight corner braking phenomenon or the like by connecting with pressure, the degree of the slip of the clutch varies depending on the amount of lubricating oil supplied and is not constant. The running of the vehicle may become unstable.

Therefore, the present invention supplies a fixed amount of lubricating oil into the input gear mount case, and discharges it through a throttle hole formed on the peripheral surface of the case to lubricate the wet friction clutch in an oil bath state. Therefore, it is an object of the present invention to provide a lubrication system for a differential control device in a power transmission device for a four-wheel drive vehicle, which solves the above problems.

(D) Means for Solving the Problem The present invention has been made in view of the above circumstances, and, for example, referring to FIG. 1, the input gear (1) is fixed in a support case (9) and is fixed. The front differential device (3) is housed in the input gear mount case (2), and the wet friction multi-plate clutch (26) and its hydraulic actuator are arranged to cover the device (3) and coaxially with the device (3). In a power transmission device for a four-wheel drive vehicle, which houses a differential control device (10) of a center differential device (18) composed of (27), lubricating oil is supplied to a lubricating oil supply hole formed in the support case (9). From (39), the sleeve portion (2b) of the input gear mount case (2) and the sleeve portion (3 of the differential case (3c) in the front differential device (3) arranged coaxially.
Through the gap (a) with respect to c ′ ₁ ), a fixed amount is supplied into the input gear mount case (2) and is discharged from the throttle hole (42) formed in the peripheral surface of the input gear mount case (2). Then, lubricating oil is stored in the input gear mount case (2) to bring the wet friction multi-plate clutch (26) into an oil bath lubrication state.

(E) Operation Based on the above configuration, the torque transmitted from the engine to the input gear (1) via the automatic transmission or the like is changed depending on the connection state of the differential control device (10) to the center differential device (18). ), It is distributed to the front differential device (3) and the rear differential device (not shown), and is transmitted to the left and right front axle shafts and rear axle shafts, respectively. Then, the lubricating oil supply hole (3
The lubricating oil from 9) is the sleeve part (2b) of the input gear mount case (2) and the sleeve (3c ' ₁ ) of the differential case (3c) in the front differential device (3).
Input gear mount case (2) through the gap (a) with
It is supplied in a fixed quantity into the inside. Then, the lubricating oil introduced into the input gear mount case (2) is
Is discharged into the support case (9) from the throttle hole (42) formed on the peripheral surface of the case (2) by the centrifugal force based on the rotation of the case (2). Therefore, the wet friction multi-plate clutch (26) always keeps a proper amount of lubricating oil in the input gear mount case 2 because the lubricating oil remains in the input gear mount case 2 over a predetermined level range. Lubrication is done in a stable oil bath.

(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 right 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). A mechanical differential lock mechanism is configured by switching between a lock position (see the upper half of the figure) that engages with a spline formed on the sleeve portion of the ring gear mount case 16 and a disengaged position (see the lower half of the figure) that disengages the spline. are doing. The mechanical differential lock mechanism is normally in a release position, but is switched to a lock position when a tire is placed on a roller at a service factory or the like to perform various inspections.

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.

As shown in detail in FIG. 1, a lubricating oil supply hole 39 is formed in the support case 9, and the lubricating oil supplied from the supply hole 39 passes through the hole 40 formed in the sleeve portion 2b. Lubricate the needle bearings 11a, 23, 23, and the like, and are discharged from the discharge hole 41 formed in the case 13 (second
(See the drawing), the lubricating oil guided to the front differential device 3 through the needle bearing 11a is introduced into the gear mount case 2 through the gap a between the sleeve portion and the sleeve 3c ' ₁ of the differential case 3c. The wet friction multi-disc clutch 26 is lubricated in a predetermined oil bath state and is discharged from a throttle hole 42 formed in the peripheral surface of the case 2. At this time, the needle bearing 11
Reference numeral a denotes an orifice that appropriately regulates the flow rate of lubricating oil depending on the number of needles and the like, and the amount of lubricating oil introduced into the case 2 is controlled to a predetermined amount. Furthermore, the sleeve part 3c
_From the hole 43 formed in 1'to the axle shaft 8r and the sleeve portion 3
The lubricating oil guided to b between c ₁ 'is supplied to the front differential case 3c through the thrust washer, and the case 3c
The lubricating oil that collects in the chamber C formed inside and overflows is discharged from the hole 46 after lubricating the thrust washer between the front differential case 3c and the mount case 2 and lubricates the roller bearing 9a. After lubricating the needle bearing 11b, the needle bearing 11b is discharged from the throttle hole 42. On the other hand, the lubricating oil supply hole formed in the support case (axle housing) 9 on the left axle shaft 8l side
The lubricating oil from 44 is the lubricating hole 45c provided in the axle shaft 8l,
Lubricate the sliding contact surface between the axle shaft 8l and the differential case 2 via 45a and 45b.

It should be noted that 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 defined by the extension case 24 and an oil seal 54 at the tip of the case is formed, and each component in the chamber D contains an extreme pressure additive sealed in the chamber D. The lubricating oil is lubricated in a system different from the above lubrication system.

Further, as shown in FIG. 3, on the surface of the second piston 29 of the hydraulic actuator 27 that contacts the clutch 26,
Even if a large number of oil grooves d ... Are formed in the radial direction and the piston 29 is in contact with the friction plate of the clutch 26,
The lubricating oil flows through the oil groove d in the radial direction of the friction plate.

 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
In the connected state, the clutch pressure reduced in proportion to the line pressure acts on both pistons 28 and 29 of the hydraulic actuator 27 through the pipe 32 and the oil passages 33 and 35, and the wet multi-plate clutch 26 is in a predetermined state. Connected by pressure. Therefore, in the center differential device 18, the differential carrier 18c and the left side gear 18a are coupled with each other with a predetermined coupling force, and the differential is limited by the predetermined regulation force. Accordingly, when the frictional force between the road surface and the tire is smaller than the above-mentioned regulation force, for example, on a road surface having a small friction coefficient such as a snow road or a dirt road, the center differential device 18 is directly connected based on the pressure force of the clutch 26. In a close state, the rotation of the 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 is further transmitted through the pinion 3p to the left and right side gears 3a, 3
The torque is distributed to b to drive the left and right front wheels, and the torque is distributed to the pinion shaft 20 via the ring gear 17 and the gear 21 fixed to the center differential device 18, and further the torque is distributed by the rear differential device to the left and right rear wheels. To drive. 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. , Differential controller 10
The friction clutch 26 also has a weak engagement force. Therefore, the center differential device based on the rotation difference between the front wheels and the rear wheels.
To allow relative rotation of the 18 left and right side gears 18a, 18b,
The friction clutch 26 controls the differential of the center differential device 2 while sliding, and transmits torque to the front and rear wheels while preventing the occurrence of a 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.
Is further transmitted to the left and right side gears 18a and 18b from the differential pinion 18p. And left side gear 1
The rotation of 8a is transmitted to the differential case 3c of the front differential device 3 through the sleeve portion 3c ₁ ', further branched and transmitted from the differential pinion 3p to the left and right side gears 3a and 3b, and transmitted to the left and right front axle shafts 8l and 8r, respectively. It 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, the lubricating oil discharged from the oil pump driven by the output shaft of the engine (not shown) is supported by the support case 9
From the lubricating oil supply hole 39 formed in the gear mounting case 2 through the hole 40 formed in the sleeve portion 2b of the gear mount case 2, a part thereof is guided toward the center differential device 18 and the remaining portion is a needle bearing. After the flow rate is adjusted by the orifice effect of 11a, the center of the input gear mount case 2 is passed through the gap a formed by the sleeve portion 2b of the input gear mount case 2 and the sleeve portion 3c ' ₁ of the differential case 3c in the front differential device 3. Part is introduced into the case 2. Then, the lubricating oil introduced into the case 2 is attached to the inner peripheral surface of the case 2 by the centrifugal force based on the rotation of the case 2, and is supported little by little by the flow rate limiting action by the throttle hole 42. It is discharged to the case 9 side. As a result, a lubricating oil layer having a predetermined level range is always formed on the inner peripheral surface of the input gear mount case 2, and the wet friction multi-plate clutch 26 of the differential control device 10 disposed in the case 2 is provided. Is always immersed in an appropriate amount of the lubricating oil layer to provide a stable lubrication state.

Further, at this time, in a normal traveling state, the hydraulic pressure based on the line pressure is constantly supplied to the hydraulic actuator 27, and the second piston 29 is always in contact with the friction plate of the clutch 26. The groove d is formed, and the lubricating oil supplied from the gap a flows through the engaging splines for the inner friction plates formed on the outer peripheral surface of the differential case 3c, and also through the oil groove d to the outside of the clutch 26. It flows to the radial side, and further flows through the engagement spline for the friction plate formed on the inner peripheral surface of the mount case 2. As a result, the clutch exchanges heat with the lubricating oil from both the inner diameter and the outer diameter of the clutch, and the friction material that is always slipped and has a high temperature is effectively cooled.

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.

(G) Effect of the Invention As described above, according to the present invention, the lubricating oil is supplied from the lubricating oil supply hole (39) formed in the support case (9).
The sleeve part (2b) of the input gear mount case (2) and the front differential device (3) arranged coaxially.
In the power transmission device in the conventional F / F vehicle, the fixed amount is supplied into the input gear mount case (2) through the gap (a) between the differential case (3c) and the sleeve portion (3c ′ ₁ ). , The lubricating oil supply hole (39) of the support case (9) formed to supply the lubricating oil to the front differential device is used as it is, and the shaft (8r) and the sleeve portions (2b), (3c) are used. ′ ₁ )
Lubricating oil can be supplied into the input gear mount case (2) by utilizing the gap (a) between the sleeve portion (2b) and the sleeve (3c ' ₁ ) without making special holes or grooves on the , Its structure is extremely simple, and processing is simple and inexpensive. Further, since the lubricating oil supplied in a fixed amount into the input gear mount case (2) is discharged from the throttle hole (42) formed on the peripheral surface of the case (2), the differential control device (10). Wet friction multi-plate clutches (26)
Is immersed in the lubricating oil bath formed on the inner peripheral surface of the gear mount case (2) in which a predetermined flow rate is flowing, and a stable lubrication state is obtained, and based on that, differential control by slipping of the clutch (26) is performed. Is always stable, so that the power transmission device (U) for a four-wheel drive vehicle operates well,
The vehicle can run stably and safely.

Particularly, in the normal state, hydraulic pressure based on the line pressure is supplied to the hydraulic actuator (27) so that the wet friction multi-plate clutch (26) is always connected with a predetermined crimping force (1).
When it is used for 0), if the oil groove (d) in the radial direction is formed on the surface of the piston (29) that contacts the clutch, even if the piston (29) is in contact with the clutch (26), the oil Lubricating oil can be supplied to the outer diameter direction of the clutch (26) through the groove (d), and the friction plate is also heat-exchanged with the lubricating oil from the outer diameter side of the clutch to improve the heat resistance of the clutch (26). You can

[Brief description of drawings]

FIG. 1 is a sectional view showing a lubricating device for a differential control device 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. And FIG. 3 is a front view showing a surface of the piston which comes into contact with the clutch. 1 ... Input gear, 2 ... Input gear mount case, 2b ...
… Sleeve part, 3 …… Front differential device, 3c …… Diff case, 3c ′ ₁ …… Sleeve part, 9 ……
Support case, 10 …… Differential control device, 18 …… Center differential device, 26 …… Wet friction multi-disc clutch, 27
...... Hydraulic actuator, 28,29 ...... Piston, 39 ......
Lubricating oil supply hole, 42 ... throttle hole, a ... gap, d ... oil groove, U ... power transmission device for four-wheel drive vehicle.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Fumitomo Yokoyama 10 Takane, Fujii-cho, Anjo City, Aichi Prefecture, Aisin Warner Co., Ltd. (72) Inventor, Yasushi Nakamura 1 Toyota-cho, Toyota City, Aichi Prefecture Toyota Co., Ltd. (72) Inventor Yuu Minamoto 1 Toyota-cho, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. (72) Inventor Mitsuo Akashi Toyota-cho, Aichi Prefecture Toyota City, Ltd. (72) Inventor Masaharu Tanaka 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd.

Claims (3)

(57) [Claims] 1. A wet differential multi-plate clutch and its hydraulic pressure are housed in an input gear mount case supported in a support case and having an input gear fixed thereto, and are covered with the device and coaxially with the device. In a power transmission device for a four-wheel drive vehicle, which accommodates a differential control device of a center differential device composed of actuators, a lubricating oil is supplied from a lubricating oil supply hole formed in the support case to the above-mentioned input arranged coaxially. Through the gap between the sleeve part of the gear mount case and the sleeve part of the differential case in the front differential device, the gas is supplied in a fixed amount into the input gear mount case and discharged from the throttle hole formed on the peripheral surface of the input gear mount case. To collect lubricating oil in the input gear mount case and A lubrication device for a differential control device in a power transmission device for a four-wheel drive vehicle, wherein the latch is in an oil bath lubrication state. 2. The differential in a power transmission device for a four-wheel drive vehicle according to claim 1, wherein the differential control device normally supplies hydraulic pressure based on a line pressure to its hydraulic actuator. Lubricator for control equipment. 3. A four-wheel drive vehicle according to claim 1, wherein a radial oil groove is formed on a surface of the piston constituting the hydraulic actuator, the surface contacting the wet friction multi-plate clutch. Lubrication device for a differential control device in a power transmission device.