JPH0646066B2 - 4-wheel drive transfer - Google Patents

Description

The present invention relates to a four-wheel drive transfer for a vehicle.

(Prior Art) Conventionally, a four-wheel drive transfer is connected behind a transmission that constitutes an automatic transmission, and outputs of the transmission are a two-wheel drive state, a four-wheel drive state, and a high-speed stage in the four-wheel drive state. It is adapted to be transmitted to the drive wheels in various drive states such as the state and the low speed stage state.

In this case, an extension case is connected to the rear part of the transmission case that houses the transmission, and the four-wheel drive transfer for switching the drive state is housed in the extension case.

A transmission mechanism case including a front sprocket case and a rear sprocket case is connected to the rear of the extension case, and inside the transmission mechanism case,
A transmission mechanism for transmitting the power transmitted from the input shaft of the four-wheel drive transfer to an output shaft arranged in parallel with the input shaft is housed.

Further, an extension housing is connected to the rear of the transmission mechanism case to support the output shaft and house a speedometer drive gear.

In the four-wheel drive transfer configured as described above, the transmission mechanism case is separated from the extension case and the extension housing, the lubrication system of the transmission mechanism between the input shaft and the output shaft is made independent, and the oil in the transmission mechanism is The oil level for lubrication of the transmission mechanism is maintained properly by not mixing with the oil in the part.

(Problems to be Solved by the Invention) However, in the above-described conventional four-wheel drive transfer, as the transmission mechanism operates in the transmission mechanism case, the oil is agitated and the oil temperature rises only. Not
The pressure inside the transmission mechanism case rises.

However, since the transmission mechanism case is isolated from the other cases, the breather mechanism arranged in the other case cannot be used, and the pressure inside the transmission mechanism case increases to prevent oil leakage. Will be generated.

Therefore, it is conceivable to dispose a breather mechanism in the transmission mechanism case, but in that case, a mixture of oil and air may blow out from the breather mechanism.

In other words, in the transmission mechanism case, the rotating part rotates to stir the oil and air to form a mixture containing bubbles in the oil, and the volume of the mixture increases as the temperature in the transmission mechanism case rises. To do. Further, due to the vortex generated in the transmission mechanism case during the operation of the transmission mechanism, the breather mechanism sucks the atmosphere.

In such a situation, when the centrifugal force due to the vortex is applied to the oil, the mixture may be blown out from the breather mechanism even if the temperature inside the transmission mechanism case is relatively low.

In addition, it is possible to form a breather chamber with a large volume to prevent oil from blowing out from the breather mechanism, but the transmission mechanism case, which originally has a larger radial dimension than the other cases, becomes even larger, making it suitable for four-wheel drive. The transferability of the transfer on the vehicle may be reduced.

The present invention solves the problems of the conventional four-wheel drive transfer described above, and disposes a breather mechanism without increasing the radial dimension of the transmission mechanism case that is liquid-tightly isolated, and An object of the present invention is to provide a four-wheel drive transfer capable of preventing the pressure in the room from fluctuating and preventing oil from blowing out from the breather mechanism.

(Means for Solving Problems) Therefore, in the four-wheel drive transfer of the present invention, an input shaft to which the output of the transmission is input,
A first output shaft drivingly connected to the input shaft coaxially and connected to one of a front wheel and a rear wheel, and arranged in parallel with the first output shaft below the first output shaft; Also,
It has a second output shaft connected to the other of the front wheels and the rear wheels, and the transmission mechanism is drivingly connected to the first output shaft and the second output shaft.

Then, a transmission mechanism case having a partition wall that liquid-tightly isolates the chamber that houses the transmission mechanism, and the first output shaft is inserted and joined to the partition wall of the transmission mechanism case to form a joint between the two. And a breather mechanism for adjusting the pressure in the chamber of the transmission mechanism case.

Further, the breather mechanism is formed in an upper portion of the first output shaft in the joint portion, is separated from the chamber of the transmission mechanism case by the partition wall, and includes a breather chamber having a hole communicating with the atmosphere. A breather passage that is formed from a lower portion to an upper portion of the first output shaft in the joint portion and communicates with the breather chamber, and the first portion of the partition wall.
A communication hole is formed in the lower portion of the output shaft and axially connects the chamber of the transmission mechanism case and the breather passage.

Moreover, each of the breather chamber and the breather passage is composed of a recess formed in the partition wall and a recess formed in the other case.

(Operation and Effect of the Invention) According to the present invention, as described above, in the four-wheel drive transfer, the input shaft to which the output of the transmission is input, and the drive shaft are coaxially connected to the input shaft. And a first output shaft connected to one of the rear wheels and a second output shaft arranged below the first output shaft in parallel with the first output shaft, and connected to the other of the front wheels and the rear wheels. An output shaft is provided, and the transmission mechanism is drivingly connected to the first output shaft and the second output shaft.

Then, a transmission mechanism case provided with a partition that liquid-tightly isolates the chamber that houses the transmission mechanism is provided, and an appropriate oil level is maintained in the transmission mechanism case.

Further, there is provided another case in which the first output shaft is inserted and which is joined to the partition wall of the transmission mechanism case to form a joint portion therebetween, and a breather mechanism which adjusts the pressure in the chamber of the transmission mechanism case. Have.

Therefore, since the inside of the transmission mechanism case communicates with the atmosphere by the breather mechanism, it is possible to prevent the pressure in the chamber of the transmission mechanism case from fluctuating.

The breather mechanism is formed in an upper portion of the first output shaft in the joint portion, is separated from the chamber of the transmission mechanism case by the partition wall, and includes a breather chamber having a hole communicating with the atmosphere. A breather passage that is formed from a lower portion to an upper portion of the first output shaft in the joint portion and communicates with the breather chamber, and the first portion of the partition wall.
A communication hole is formed in the lower part of the output shaft and connects the chamber of the transmission mechanism case with the pressure passage in the axial direction.

In this case, when the transmission mechanism is operated in the transmission mechanism case, the rotating portion rotates to stir the oil in the transmission mechanism case and raise the temperature of the oil.
A vortex is generated by the mixture of bubbles in the oil.

However, since the communication hole is formed at a position higher than the bottom of the chamber of the transmission mechanism case, the oil that is caused to flow by the rotation of the rotating portion of the transmission mechanism does not easily reach the communication hole.

Further, since the communication hole axially connects the chamber of the transmission mechanism case and the breather passage, the oil spattered in the radial direction is prevented from entering the breather passage when the rotating portion of the transmission mechanism rotates. Can be prevented.

Even if oil enters the breather passage through the communication hole, the breather passage still has the first portion at the joining portion.
Since it is formed from the lower part to the upper part of the output shaft, oil does not enter the breather chamber due to the airflow flowing from the inside of the transmission mechanism case to the breather chamber through the breather mechanism, and the oil enters the transmission mechanism case again. Run down.

Further, the breather chamber and the breather passage are both formed of a recess formed in the partition wall and a recess formed in the other case, and the chamber of the transmission mechanism case and the breather passage are axially formed by a communication hole. Have been contacted.

Therefore, the breather mechanism can be formed without increasing the radial dimension of the transmission mechanism case. Moreover, since the breather passage is formed from the lower portion to the upper portion of the first output shaft in the joint portion, the breather passage can be made sufficiently long and oil can be prevented from entering the breather chamber. It can be further prevented.

(Example) Hereinafter, the Example of this invention is described in detail, referring drawings.

FIG. 1 shows a four-wheel drive transfer (hereinafter abbreviated as transfer) of the present invention.

Transfers stored in transfer case 2 1
Is an output shaft 32 of the planetary gear set in the transmission case, which is a friction engagement element such as a clutch C3, a brake B4 and a clutch C4, and is arranged in series with the input shaft (32). Of the extension housing 21b joined to the partition wall 24 provided on the output side of the housing 21b.
A speedometer drive gear 41 is provided inside, and a first output shaft 42 of the transfer 1, which is rotatably supported on the extension housing 21b on the output side, of the input shaft (32) and the first output shaft 42. A four-wheel drive sleeve rotatably fitted to the first output shaft 42 in a front sprocket case 22 and a rear sprocket case 23, which are transmission mechanism cases, having a planetary gear speed change mechanism 40A disposed therebetween.
51, the first output shaft 42 below the first output shaft 42
A second output shaft 52 disposed in parallel with the first output shaft 42 and mounted in a direction opposite to the first output shaft 42, the sleeve 51 and the second output shaft 52.
It has a transmission mechanism 53 and a breather mechanism 20 between and.

The planetary gear speed change mechanism 40A is housed in an extension case 21a, which is another case in which the input of the front sprocket case 22 is arranged on the crocodile, and comprises a planetary gear set Pf, a brake B4, clutches C3, C4.

The planetary gear set Pf includes a sun gear 44 spline-fitted to the end of the input shaft (32), a planetary pinion 45 meshing with the sun gear 44, a ring gear 46 meshing with the planetary pinion 45, and the planetary pinion 45. The brake B4, which is a multi-plate friction brake for engaging the ring gear 46 with the extension case 21a, holds the rotatably and the carrier 47 connected to the first output shaft 42 of the transfer 1.
It is operated by a hydraulic servo B-4 composed of a cylinder 49 formed in 21a and a piston 49P mounted in the cylinder 49.

The clutch C3 is disposed on the automatic transmission side of the planetary gear set Pf, and connects and disconnects the sun gear 44 and the carrier 47. The clutch C3 is connected to the carrier 47 and the piston 50P mounted in the cylinder 50. Is operated by a hydraulic servo C-3.

The clutch C4 is a transmission mechanism for driving the first output shaft 42 connected to the carrier 47 and the second output shaft 52 of the transfer 1.
53 is a multi-plate friction clutch for connecting / disconnecting the sleeve 51 connected to one sprocket 56, and the first output shaft 42
It is operated by a hydraulic servo C-4 composed of a cylinder 58 supported by the cylinder 58 and a piston 58P mounted in the cylinder 58. The transmission mechanism 53 includes the front sprocket case 2
2. The sprocket 55, which is housed in the sprocket case chamber 21 which is a transmission mechanism case chamber and is separated by the rear sprocket case 23 to secure an appropriate oil level, is spline-fitted to the sleeve 51, and the second output shaft 52 is formed. The sprocket 56 and the chain 57 stretched between the sprockets 55, 56.

A parking gear 59 is provided around the hydraulic cylinder 50 of the hydraulic servo C-3. When the shift lever of the automatic transmission is selected at the parking position, the pawl 59A meshes with a parking claw (not shown). The first output shaft 42 is fixed.

Reference numeral 60 designates a transfer valve body provided with a hydraulic control device for supplying / discharging hydraulic pressure to / from the hydraulic servos C-3, C-4 and B-4 of the clutches C3, C4 and brake B4 of the transfer 1, and 61 designates an oil pan thereof. is there. Clutch C
3, C4 and brake B4 hydraulic servos C-3, C-
The pressure oil supplied to 4 and B-4 is guided to a transfer valve body 60 provided with a transfer hydraulic control device 62 via an oil passage 64 provided in the transmission case and the extension case 21a.

During normal driving, the hydraulic servo C-3 is supplied with the line pressure supplied to the hydraulic control device of the automatic transmission to engage the clutch C3, and the hydraulic servos B-4 and C-4 are discharged to brake B4 and the clutch. Release C4. As a result, the sun gear 44 and the carrier 47 of the planetary gear set Pf are connected, power is transmitted from the input shaft (32) to the rear wheel drive first output shaft 42 at a reduction ratio of 1, and only rear wheel two-wheel drive travel is performed. can get. At this time, the power from the input shaft (32) is
The first output shaft from the carrier 47 via the clutch C3 without passing through the sun gear 44, the planetary pinion 45, and the ring gear 46.
Since it is transmitted to 42, no load is applied to the tooth surface of each gear,
Gear life is increased. When it becomes necessary to drive four wheels during this two-wheel drive, the shift lever provided in the driver's seat or the like is manually shifted to gradually supply the line pressure to the hydraulic servo C-4 of the transfer hydraulic control device 62 so that the clutch is operated. When C4 is smoothly engaged, the first output shaft 42 and the sleeve 51 are connected, and the power is transmitted to the front wheels via the transmission mechanism 53, the second output shaft 52 and the propeller shaft (not shown), and the input shaft is transmitted. From (32), power is transmitted to the first output shaft 42 for driving the rear wheels and the second output shaft 52 for driving the front wheels at a reduction ratio of 1, and a four-wheel drive direct-coupling traveling state (high-speed four-wheel drive state) is obtained. If the shift lever is manually shifted when the output torque needs to be increased while driving on a steep road during 4-wheel drive, the hydraulic pressure for the hydraulic servo causes the switching valve to switch between the high-speed 4-wheel drive state and the low-speed 4-wheel drive state. The line pressure is gradually supplied to the servo B-4 and the hydraulic pressure of the hydraulic servo C-3 is discharged at an appropriate timing to gradually engage the brake B4 and smoothly release the clutch C3. As a result, the sun gear 44 and the carrier 47 are released and the ring gear 46 is fixed, and the power is decelerated from the input shaft (32) via the sun gear 44, the planetary pinion 45, and the carrier 47, and the first output shaft 42.
Then, the torque is transmitted to the second output shaft 52, and a four-wheel drive decelerated traveling state with a large torque (low-speed four-wheel drive state) is obtained. Table 1
Setting range of manual transfer shift and brake B
4, engagement and disengagement of the clutches C3 and C4, and the running state of the vehicle are shown.

In Table 1, ∘ indicates the engaged state of the friction engagement element, and × indicates the released state. The reduction ratio (3.0 in the example) was calculated by the reduction ratio = (1 + λ) / λ = 3.0 when the tooth number ratio of the sun gear 44 and the ring gear 46 of the planetary gear mechanism is λ and the tooth number ratio λ is 0.5. It is a thing.

Breather mechanism 20 of four-wheel drive transfer 1 of the present invention
1 to 6, is formed on a partition wall 24 which is located on the side of the sprocket 55 of the rear sprocket case 23 and which separates the sprocket case chamber 21 and the extension housing 21b from each other. The partition wall is provided axially at a position corresponding to the lower portion of the output shaft 42, and
A communication hole 26 around which a projecting portion 25 projecting into the sprocket case chamber 21 from 24 is arranged, and a breather chamber independently provided above the joint portions 31 and 27 of the rear sprocket case 23 and the extension housing 21b, Rear sprocket case 23 and extension housing 21
The breather passages 31a and 27a provided at the joint portions 31 and 27 of b and extending upward from the communication hole 26 and connecting the communication hole 26 and the breather chamber 28, and the breather passages 31a and 27a.
Ribs 33 provided on the extension housing 21
The breather chamber 28 is provided in b, and the hole 28a communicates with the atmosphere of the extension housing 21b. The breather cap 29 is attached to the hole 28a and prevents water and the like from entering the breather chamber 28. Communication hole 26, breather chamber 2
8 and the breather passages 27a and 31a are integrally formed when the rear sprocket case 23 and the extension housing 21b are cast. That is,
When casting the rear sprocket case 23 and the extension housing 21b, the joining portions 27, 31
In the partition wall 24, and the partition wall 24 in the extension housing 21b.
The recess is formed so as to correspond to the recess.

Therefore, by simply joining the rear sprocket case 23 and the extension housing 21b, the communication hole 26, the breather chamber 28 and the breather passage 27a,
31a can be formed.

Since the inside of the transmission mechanism case including the front sprocket case 22 and the rear sprocket case 23 communicates with the atmosphere through the communication hole 26, the breather passages 27a and 31a, and the breather chamber 28, the interior of the transmission mechanism case It is possible to prevent the pressure of V from fluctuating.

In the breather mechanism, the rear sprocket case 23 and the extension housing 21b
A breather chamber 28, which is separated from the chamber of the transmission mechanism case by the partition wall 24, is formed above the first output shaft 42 at the joints 27 and 31 of the breather chamber 2 of FIG.
8 has a hole communicating with the atmosphere. In addition, the joint 2
Breather passages 27a and 31a are formed from the lower part of the first output shaft 42 to the upper part of the first output shaft 7 and 31, and communicate with the breather chamber 28. Then, a communication hole 26 is formed in the partition wall 24 below the first output shaft 42,
The inside of the transmission mechanism case and the breather passage 27a,
31a in the axial direction.

Therefore, as the rotating part of the transmission mechanism 53 rotates in the transmission mechanism case, the temperature of the oil in the transmission mechanism case rises and a mixture of bubbles in the oil generates a swirl flow. 26 and Breather Room 2
8 is connected by the breather passages 27a and 31a extending upward from the joints 27 and 31, so that oil does not blow out from the hole communicating with the atmosphere of the breather chamber 28.

Further, since the communication hole 26 is disposed on the side of the transmission mechanism 53, it is possible to prevent the oil scattered by the rotation of the rotating portion of the transmission mechanism 53 from entering the breather passages 27a, 31a. Instead, since the protrusion 25 is formed in the communication hole 26, it is possible to prevent oil from entering the communication hole 26 along the transmission mechanism case.

The ribs 33 for reducing the passage area are formed in the breather passages 27a and 31a that connect the communication hole 26 and the breather chamber 28 to each other.
The bubbles of the mixture that have entered the insides of 7a and 31a can be extinguished, and the oil can be returned to the inside of the transmission mechanism case.

Further, the breather chamber 28 and the breather passage 2
7a and 31a each include a concave portion formed in the partition wall 24 and a concave portion formed in the extension housing 21b, and the chamber of the transmission mechanism case and the breather passages 27a and 31a are axially connected by a communication hole 26. I am in touch.

Therefore, the breather mechanism can be formed without increasing the radial dimension of the transmission mechanism case. Moreover, the breather passages 27a and 31a are connected to the joining portion 2
The breather passage 27 is formed from the lower part to the upper part of the first output shaft 42 at 7, 31.
a, 31a can be made sufficiently long, and the breather chamber 2
It is possible to further prevent oil from entering into 8.

In FIG. 5, the alternate long and short dash line indicates the position corresponding to the communication hole 26.

The transmission mechanism case (rear sprocket case 23 in this embodiment) and the other case (extension housing 21b in this embodiment) are connected to the communication hole 26 and the breather chamber during casting.
Since 28 can be formed, processing after casting is almost unnecessary.

[Brief description of drawings]

FIG. 1 is a sectional view of a four-wheel drive transfer, and FIG.
The front view of the input shaft of the rear sprocket case for the wheel drive transfer, FIG. 3 is a sectional view taken along line AA of FIG.
Fig. 4 is a front view of the output of the rear sprocket case of the four-wheel drive transfer, Fig. 5 is a front view of the input of the extension housing of the four-wheel drive transfer, and Fig. 6 is C of Fig. 5. FIG. In the figure, 1 …… Transfer, 2 …… Transfer case,
20: Breather mechanism, 21b: Extension housing (other case), 22: Front sprocket case,
23 …… rear sprocket case, 26 …… communication hole, 28 ……
Breather chamber, 28a ... hole, 29 ... breather cap, 2
7a, 31a ... Breather passage

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yoshiharu Harada 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Co., Ltd. Examiner Masaya Deguchi (56) Bibliography Sho 54-52537 (JP, U) Sho 59-22365 (JP, B2)

Claims (4)

[Claims] 1. An input shaft to which an output of a transmission is input, a first output shaft which is drivingly connected to the input shaft coaxially, and is connected to one of a front wheel and a rear wheel, and the first output shaft. A second output shaft that is disposed below the first output shaft in parallel with the first output shaft and that is connected to the other of the front wheel and the rear wheel, and a transmission that drives and connects the first output shaft and the second output shaft. A mechanism, a transmission mechanism case having a partition wall that liquid-tightly isolates a chamber that houses the transmission mechanism, a first output shaft that is inserted, and is joined to the partition wall of the transmission mechanism case and joined between them. And a breather mechanism for adjusting the pressure in the chamber of the transmission mechanism case, the breather mechanism being formed above the first output shaft in the joint portion, and having the transmission mechanism. Depending on the interior of the case and the partition Isolated, and the breather chamber having a bore communicating with the atmosphere, the first at the joint
A breather passage that is formed from the lower part to the upper part of the output shaft and that communicates with the breather chamber, and an inner part of the transmission mechanism case and the breather passage that are formed below the first output shaft in the partition wall in the axial direction. And a communicating hole communicating with the breather chamber, and the breather chamber and the breather passage are each formed of a recess formed in the partition wall and a recess formed in the other case. transfer. 2. The communication hole according to claim 1, wherein the communication hole provided in the partition wall is located laterally of the transmission mechanism.
Wheel drive transfer. 3. The four-wheel drive transfer according to claim 2, wherein the breather passage is formed with a rib that reduces the passage area. 4. The four-wheel drive transfer according to claim 3, wherein a projecting portion that projects inward of the transmission mechanism case is formed around the communication hole of the partition wall.