JP3518244B2 - Final reduction gear and its assembling method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a final reduction gear used for a front differential, a rear differential, etc. in a vehicle and a method for assembling the final reduction gear.

[0002]

2. Description of the Related Art In this type of final reduction gear, a pair of left and right side gears and a pinion gear meshing with these side gears are housed in a differential case, the differential case is rotatably supported, and a drive pinion is attached to a ring gear attached to the differential case. It is generally configured by meshing.
In addition to connecting the propeller shaft to the drive pinion, connecting the left and right axles to each side gear, transmitting torque from the propeller shaft to each axle, and rotating the left and right axles (wheels) by rotating the pinion. I have to.

Since this final reduction gear is mounted at a position distant from a power source such as an engine or a transmission, it is difficult to perform forced lubrication using an oil pump, and the final reduction gear itself is used for internal equipment. It is necessary to lubricate. Therefore, conventionally, a ring gear having the largest diameter is generally used to scrape up the lubricating oil to supply the lubricating oil to the tooth flanks and the bearings. For the drive pinion bearings that are relatively distant from the ring gear, an oil passage is formed in the casing, and the lubricating oil scraped up by the ring gear is used for the drive pinion bearing. It is configured so as to lead to Japanese Patent Application Laid-Open No. 8-
No. 210472.

The final deceleration device rotates at a high speed according to the running state of the vehicle, or receives a large torque, and further receives the vibration and impact force from the axle side during running.
Being in a mechanically harsh situation. Therefore, since the casing is required to have high strength, cast iron castings have been generally used in the past. With such a configuration, the oil passage for the lubricating oil described above can be formed using a core or the like. However, on the other hand, the weight becomes heavy,
This will impede the demand for vehicle weight reduction. For the purpose of eliminating such inconvenience, JP-A-61-116
In the invention described in Japanese Patent No. 6724, the casing is made of aluminum die cast, and the casing is divided into a main body and a lid body on a plane perpendicular to the central axis of the ring gear or the side gear, and die cutting during casting is performed. It is possible.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
If the casing is made of aluminum die casting as described in Japanese Patent No. 66724, the weight can be reduced and the manufacturing cost can be reduced. However, as described above, since the final reduction gear has various inputs from low rotation speed / low torque to high rotation speed / high torque, it also incorporates gears that transmit these torques. It is easy to become a source of vibration and noise. Therefore, if the casing is simply made of aluminum, the sound insulation function will decrease with the weight reduction, and there is a possibility that vibration will be transmitted to the vehicle body and noise will increase in the vehicle. .

Further, as described in JP-A-8-210472, when lubricating a drive pinion bearing with lubricating oil scraped up by a ring gear, an oil passage for guiding the lubricating oil to the bearing is The shape extends from the ring gear side in a direction substantially orthogonal to the central axis thereof, and its end portion is bent in a direction perpendicular to the central axis of the drive pinion. Therefore, the structure described in Japanese Unexamined Patent Publication No. 61-166724, in which the casing is divided into a main body and a lid, is disclosed in Japanese Unexamined Patent Publication No. 8-210.
If it is applied to the differential described in Japanese Patent No. 472, undercut occurs in the portion at the time of die casting due to the curved oil passage as described above, and as a result, for forming the oil passage. This causes inconvenience such as requiring post-processing.

The present invention has been made in view of the above circumstances, and provides a final speed reducer which is easy to manufacture from aluminum die casting and is advantageous in reducing vibration and noise, and a manufacturing method thereof. The purpose is to do.

[0008]

In order to solve the above-mentioned problems, the invention described in claim 1 is directed to a differential mechanism having a ring gear as an input element and a differential mechanism which is perpendicular to the center axis of rotation of the ring gear. A drive pinion having a center axis of rotation set in a plane and meshed with a ring gear, a bearing that rotatably supports the drive pinion, and a casing that forms an oil passage that guides the lubricating oil scraped up by the ring gear to the bearing. In the final reduction gear transmission including, the casing is divided into a main body portion and a lid portion,
Check whether the main body is perpendicular to the center axis of the ring gear.
The scent that is parallel to the axis of the drive pinion
The ring gear of the entire space for accommodating the differential mechanism.
And a bearing side that rotatably supports the differential mechanism on the side
The side surface in the direction in which the oil passage extends in succession to
Forming at least the ring gear side of the oil passage.
The drive pinion is rotatably supported from the open end of the
The part up to the opening end on the bearing side opens to the opening surface.
Is formed on the main body in a state of
It is characterized in that it is formed so as to seal .

Therefore, according to the first aspect of the invention, the oil passage extending in the axial direction of the drive pinion from the ring gear side has a so-called side surface open to the side, so that the molding die is inserted from the dividing surface side. By advancing and retracting, the oil passage and the portion opened from the oil passage toward the drive pinion bearing can be formed. That is, according to the first aspect of the present invention, the aluminum die casting of the casing is possible, and the post-processing other than the processing associated with the normal die casting is not required, so that the manufacturing cost can be reduced. Further, since the lid has a structure extending in the axial direction of the drive pinion like the oil passage, the rigidity of the casing increases as the bending rigidity of the lid increases, and as a result, the resonance point of the casing increases. It becomes possible to reduce the noise by increasing.

[0010] The method of claim 2, claim
In 1, the pre-Symbol casing, as well as divided into a main body portion and the lid portion in substantially parallel dividing surfaces relative to the central axis of and the drive pinion perpendicular to the central axis of the ring gear, these main body and the lid Part is temporarily assembled, the fitting part for the bearing that supports the differential mechanism is machined, and in that state, a knock pin hole that penetrates the lid part and reaches the main body part is punched, and then the lid part. After assembling the internal parts including the differential mechanism and the bearing to the main body in a state in which the main body is removed from the main body, a knock pin is attached to the knock pin hole of the main body or the lid, and the lid and the main body are based on the knock pin. Is a method of assembling the final reduction gear transmission.

Therefore, according to the second aspect of the present invention, bearings are attached to the main body and the lid to rotatably support the differential mechanism.
Finishing processing such as grinding is performed at the same time in a state where the main body and the lid are integrated. At the same time, a knock pin hole is drilled through the lid portion to the body portion. Therefore, after assembling the components such as the differential mechanism and the bearing inside the main body, if the lid and the main body are integrated via a knock pin attached to either one of the main body and the lid, The bearings supporting the differential mechanism are arranged exactly on the same axis. Therefore, it is possible to prevent the displacement of the shaft center, the vibration or noise resulting from the displacement, and the wear.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described more specifically. FIG. 1 shows an example in which the final reduction gear of the present invention is configured as a rear differential for a vehicle. As shown in FIG. 1, a differential mechanism 2 and a drive pinion for driving the differential mechanism 2 are provided inside a casing (differential carrier) 1. 3 and 3 are accommodated. The differential mechanism 2 has a well-known configuration, and the differential case 5 is rotatably supported on both left and right sides (upper and lower sides in FIG. 1) by a pair of tapered roller bearings 4.
A pair of left and right side gears 6 whose center of rotation is aligned with the axis of the differential case 5 are rotatably arranged inside the gear, and the pinion gear 7 meshed with these side gears 6
Is rotatably held by a pinion pin 8 attached to the differential case 5 so as to be orthogonal to the rotation center axis of the differential case 5. That is, the pinion gear 7 is configured to revolve with the differential case 5 and rotate about the pinion pin 8.

On the outer surface of the differential case 5, there is fixed a ring gear 9 whose rotation center axis coincides with the rotation axis thereof. The ring gear 9 is composed of a hypoid gear, and a drive pinion 3 having a rotation center axis set in a plane perpendicular to the rotation axis thereof meshes with the ring gear 9. Therefore, the ring gear 9 is an input element for the differential mechanism 2.

The structure of the casing 1 accommodating the differential mechanism 2 and the drive pinion 3 will be described below.
The casing 1 is composed of a main body 10 and a lid 11. The main body portion 10 accommodates and supports the other constituent members excluding the one bearing 4 supporting the differential case 5, and thus has a shape in which the one bearing 4 side is open. Further, the main body portion 10 is formed with a cylindrical portion 12 extending from a space portion accommodating the differential mechanism 2 in a plane direction perpendicular to a rotation axis of the differential mechanism 2. The cylindrical portion 12 is a portion for rotatably supporting the shaft portion 13 of the drive pinion 3, and tapered roller bearings 14 are fitted and fixed at two front and rear positions in the axial direction. The shaft portion 13 of the drive pinion 3 is inserted into these bearings 14 and is rotatably held by the bearings 14.

In each bearing 14, the end on the small diameter side of each inner race is positioned on the center side in the axial direction of the cylindrical portion 12, that is, the end on the small diameter side is abutted. It is arranged. Therefore, the centrifugal force caused by the rotation causes a pump action to pressurize the fluid from the central portion side in the axial direction of the cylindrical portion 12 toward the outside.

Further, oil passages 15 and 16 for lubricating oil are formed on the side portion (lower side in FIG. 1) of the cylindrical portion 12 described above. These oil passages 15 and 16 are shown in FIG.
A supply oil passage 15 for supplying lubricating oil to the bearing 14 is formed on the upper side in a state where the rotation axis of the differential mechanism 2 and the rotation axis of the drive pinion 3 are substantially horizontal, A return oil passage 16 for guiding the lubricating oil returning from the bearing 14 located away from the pinion 3 to the differential mechanism 2 side is formed below the return oil passage 16.

The oil supply passage 15 will be further described. Inside the main body portion 10, a partition wall 17 for vertically dividing a space portion is provided.
By extending in a direction substantially parallel to the shaft portion 13 of the drive pinion 3, the supply oil passage 15 is formed above the partition wall 17. Therefore, the supply oil passage 15 is located outside in the radial direction of the ring gear 9 and opens toward the ring gear 9. At the end of the supply path 15 opposite to the ring gear 9, a supply port 18 is formed between a bearing 14 that rotatably supports the shaft 13 of the drive pinion 3. Therefore, the supply port 18 is directed vertically in FIG.
Further, in FIG. 2, it is formed in a direction perpendicular to the paper surface.

The oil passages 15 and 16 have a cylindrical portion 12
Since it is formed on the lid portion 11 side with respect to the main body portion 10, it has a shape that is opened over the entire length toward the side portion of the main body portion 10, and therefore the supply oil passage 15 and the supply port 18 at the end portion thereof. When the main body 10 is cast, the die can be die-cut from the side.

The return oil passage 16 formed below the partition wall 17 is also formed to be positioned outside in the radial direction of the ring gear 9, and one end of the return oil passage 16 opens close to the ring gear 9 and The other end extends to a position of the bearing 14 supporting the shaft 13 beyond the bearing 14 at a position distant from the drive pinion 3, and further has a discharge port 19 opening at a position beyond the outer bearing 14. Has been formed. Therefore, the discharge port 19 is also formed in the vertical direction of FIG. 1 and the direction perpendicular to the paper surface of FIG. 2 similarly to the supply port 18. And this return oil passage 1
Since 6 is opened toward the lid 11 side, the return oil passage 16 and the discharge port 19 on the other end side are also
The side portion of the main body portion 10 has a structure that allows die cutting.

Therefore, in the main body portion 10, the entire space for accommodating the differential mechanism 2 is opened to the side of one bearing 4 that rotatably supports the differential mechanism 2, and the oil passages 15, 1 are continuously connected to this.
The side surface of 6 in the extending direction is open to the crocodile. The lid 11
Seals this opening, and therefore its shape is a rectangular shape that extends along the oil passages 15 and 16 into a circular shape in which the space portion that accommodates the differential mechanism 2 is projected in the direction of its rotation axis. Is a continuous shape, and the shape is shown in FIG. The end of the rectangular portion of the lid 11 extends to near the end of the main body 10.

Further, one bearing 4 for rotatably supporting the differential mechanism 2 is fitted and fixed to the lid portion 11. Therefore, each of the pair of bearings 4 that rotatably supports the differential mechanism 2 needs to be positioned on the same axis, and therefore, in the final reduction gear transmission according to the present invention, the main body 10 and the lid 11 are separated from each other. They are integrated as follows. That is, as shown in FIG. 3, the lid portion 11 is fixed to the main body portion 10 by a plurality of bolts 20 penetrating the peripheral portion thereof. Further, a knock pin 21 penetrates and is attached to a position close to each of the two bolts 20, and the lid portion 11 is positioned with respect to the main body portion 10 with the knock pin 21 as a reference. In this state, the bolt 20 is fixed to the main body 10. By doing so, the bearing 4 in the main body portion 10 and the bearing 4 in the lid portion 11 are arranged with their axes aligned.

The shaft portion 13 of the drive pinion 3
Is rotatably held by the bearings 14 and 14, and its end projects from the main body 10. A cylindrical holder 22 is attached to the end of the main body 10 from which the shaft 13 projects, and a viscous coupling 23 is rotatably held inside the holder 22. This viscous coupling 23 is a conventionally known one, in which a hub 25 is concentrically and rotatably held inside a cylindrical outer case 24, and a spline fitting is performed on the inner peripheral surface of the outer case 24. A plurality of outer plates combined with each other and a plurality of inner plates spline-fitted to the outer peripheral surface of the hub 25 are alternately arranged in the axial direction, and the inner space of these outer cases 24 is placed together with a viscous fluid such as silicone oil. A fixed amount of air is enclosed.

Reference numeral 26 in the drawing denotes an oil seal. These oil seals 26 are provided between the axle 27 connected to each side gear 6 and the main body 10 and the lid 11.
The casing 1 is interposed between the outer case 24 and the main body 10 to seal the casing 1 in a liquid-tight state.

As described above, the casing 1 includes the main body 1
It is divided into 0 and the lid portion 11, and the dividing surface 28 is set to be perpendicular to the axis of the ring gear 9 and substantially parallel to the axis of the drive pinion 3. Then, by assembling the main body portion 10 and the lid portion 11 as described above, and by assembling the viscous coupling 23 and the axle 27, the inside of the casing 1 is hermetically sealed, and a predetermined amount of lubricating oil is sealed inside. .

In the above-described final speed reducer, in the vehicle mounted state, the rotation center axis of the differential mechanism 2 is horizontal and the drive pinion 3 is provided.
Has a substantially horizontal center axis (may be tilted slightly upward), so that the lubricating oil sealed in the main body portion 10 is accumulated at the bottom portion thereof. When a propeller shaft (not shown) connected to the viscous coupling 23 is rotated in that state, torque is input to the differential mechanism 2 via the viscous coupling 23, the drive pinion 3 and the ring gear 9. The rotation direction of the ring gear 9 in that case is the counterclockwise direction in FIG. 2, and such rotation of the ring gear 9 scrapes up the lubricating oil accumulated at the bottom of the main body portion 10, and further the centrifugal force causes the ring gear 9 to move from the ring gear 9. Supply oil passage 15 by scattering
Lubricating oil is supplied to the portion between the supply port 18 and the bearing 14 via the supply oil passage 15.

As described above, the bearing 14 is a tapered roller bearing and is arranged with the ends of the inner race on the small diameter side facing each other. The radial pumping force is generated, and as a result, the lubricating oil supplied from the supply port 18 is caused to flow across the bearing 14 by the pumping action of the bearing 14. That is, the bearing 14 is lubricated.
The lubricating oil that has passed through the bearing 14 on the right side of FIG.
The lubricating oil that has returned to the bottom portion of the left side of FIG. 1 and passed through the bearing 14 on the left side of FIG. 1 reaches the return oil passage 16 from the discharge port 19 and reaches the bottom portion of the main body portion 10 where the differential mechanism 2 is accommodated. Return.

The oil passages 15 and 16 acting in this way are
In use, it forms a so-called tunnel-shaped passage,
The one side portion is closed by the lid portion 11.
In other words, the side portion of each oil passage 15 and 16 has the casing 1
Is open on the side of the dividing surface 28. Therefore, the oil passages 15 and 16 and the supply port 18 and the discharge port 19 formed at the respective ends can be formed by inserting a molding die from the side of the dividing surface 28, and the main body 10
There is no undercut when die casting.

Further, as shown in FIG. 3, the above casing 1
Is a lid portion 11 that extends in the axial direction of the drive pinion 3 and torque is input via the drive pinion 3, but that seals the side surface portion of the casing 1.
Is a shape extending in the axial direction of the drive pinion 3, and its second moment of area is large. Therefore, the rigidity of the casing 1 in the final reduction gear transmission is increased, and the noise vibration characteristics (NV characteristics) are improved.

FIG. 4 shows the results of examining the noise characteristics. The chain line in FIG. 4 shows the characteristics of the final reduction gear with the casing configured as described above, and the solid line shows the simple disk shape of the lid. The characteristics of the final reduction gear of the casing are shown. As is known from FIG. 4, in the above final reduction gear transmission according to the present invention, the sound pressure level of 500 to 600 Hz can be lowered, and resonance can be prevented to reduce noise caused by a humming noise and the like. it can.

By the way, in the above final reduction gear transmission, the dividing surface 28 of the casing 1 is a plane which is perpendicular to the central axis of the differential mechanism 2 (or the ring gear 9) and is substantially parallel to the axis of the drive pinion 3 as described above. Since it was set to
Bearings 4 and 4 that support the differential mechanism 2 include a main body portion 10 and a lid portion 1.
1 will be installed. So these bearings 4,
In order to match the axes of 4 in FIG.
It is assembled by the procedure shown in.

First, the main body portion 10 and the lid portion 11 are manufactured by die casting, and are subjected to predetermined machining such as deburring and screwing. Then, the main body 10 and the lid 11 are temporarily assembled with the bolt 20. In that state, the mounting hole 40 for the bearing 4 in the main body portion 10 and the lid portion 11
Are simultaneously machined (eg, ground). Therefore, since the mounting holes 40 are machined while the axis of the machining tool is kept constant, the mounting holes 40 are not machined.
Is machined so that its axes match. At the same time,
Knock pin hole 4 that penetrates the lid 11 and reaches the main body 10.
Drill 1, 41.

Next, the main body 10 and the lid 11 are separated,
The differential mechanism 2, the bearings 4, 14 or the drive pinion 3 are assembled inside the main body 10, and the bearing 4 is assembled on the lid 11. After that, a knock pin 21 is attached to the knock pin hole in the main body portion 10, the lid portion 11 is permanently assembled to the main body portion 10 with the knock pin 21 as a reference, and in that state, the lid portion 11 is fixed to the main body portion 10 by the bolt 20. To do.

Therefore, since the knock pin hole 41 is formed at the time of processing the mounting hole 40 for the bearing, if the lid portion 11 is attached to the main body portion 10 with the knock pin 21 attached to the knock pin hole 41 as a reference, The relative position between the main body portion 10 and the lid portion 11 at the time of processing the bearing mounting hole 40 is reproduced. As a result, the axes of the mounting holes 40 for the bearings are aligned. Therefore, the feature of the above assembling method appears in that the knock pin hole 41 in the lid portion 11 penetrates the lid portion 11.

Although the present invention has been specifically described above, the present invention is not limited to the above-described examples, and the positions and the number of the knock pins can be appropriately changed as necessary. The drive pinion may be directly connected to the propeller shaft without a viscous coupling. Further, a part of the oil passage may be formed in the lid portion.

[0035]

As described above, according to the final reduction gear system of the present invention, the oil passage that supplies the lubricating oil to the bearing and returns from the bearing side does not become an undercut during die casting. Therefore, the casing can be manufactured at low cost by die casting. Also, since the lid that seals the main body has a shape that extends along the oil passage, the rigidity is high even if the casing has a divided structure, and even if it is made of aluminum, the resonance point of the casing becomes high. It is possible to reduce noise.

Further, according to the method of the present invention, the shaft center of the bearing mounting hole in the main body portion and the shaft center of the bearing mounting hole in the lid portion can be accurately aligned with each other, and therefore the shaft center is displaced during assembly. It is possible to prevent vibration, noise, and wear caused by this.

[Brief description of drawings]

FIG. 1 is a cross-sectional plan view showing an example of a final reduction gear transmission according to the present invention.

FIG. 2 is a side view showing a portion of an oil passage in the main body.

3 is a side view of the final reduction gear transmission shown in FIG. 1. FIG.

FIG. 4 is a diagram showing a noise characteristic of the final reduction gear transmission shown in FIG. 1 and a noise characteristic of an example in which a lid has a disk shape.

FIG. 5 is a flowchart showing an assembling procedure of the final reduction gear transmission according to the present invention.

[Explanation of symbols]

1 casing 2 differential mechanism 3 drive pinion 4,14 bearing 9 ring gear 10 Main body 11 Lid 13 Shaft 15, 16 oil passage 18 Supply port 19 outlet 21 knock pin 28 division plane 40 mounting holes 41 Dowel pin hole

─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-8-210472 (JP, A) JP-A-63-158357 (JP, A) JP-A-63-158358 (JP, A) Practical application Sho-63- 3559 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H 57/00-57/12 B23P 19/00-21/00

Claims (2)

(57) [Claims] 1. A differential mechanism having a ring gear as an input element, a drive pinion having a rotation center axis set in a plane perpendicular to the rotation center axis of the ring gear and meshing with the ring gear, and the drive pinion being rotatable. In a final reduction gear including a supporting bearing and a casing having an oil passage for guiding the lubricating oil scraped up by the ring gear to the bearing, the casing is divided into a main body portion and a lid portion, and the main body
Is perpendicular to the central axis of the ring gear and
In a plane parallel to the axis of the drive pinion,
On the ring gear side of the entire space that houses the differential mechanism
The bearing side that rotatably supports the differential mechanism and the
Next, the side surface of the oil passage in the direction of extension forms a crocodile opening surface.
Open at least the ring gear side of the oil passage.
A shaft that rotatably supports the drive pinion from the mouth end
The state where the part up to the opening end on the receiving side is open to the opening surface
Is formed on the main body, and the lid closes the opening surface.
A final speed reducer characterized by being formed so as to close . 2. A method before Symbol casing, as well as divided into a main body portion and the lid portion in substantially parallel dividing surface with respect to the central axis of the vertical and and the drive pinion with respect to the central axis of the ring gear, these body portions In a state where the lid and the lid are temporarily assembled, the fitting portion for the bearing that supports the differential mechanism is machined, and in that state, a knock pin hole that penetrates the lid and reaches the main body is punched. After assembling the internal parts including the differential mechanism and the bearing to the main body with the lid removed from the main body, a knock pin is attached to the knock pin hole of the main body or the lid, and the lid is referenced with the knock pin. billing you, characterized in that the assembling the main body portion
Item 3. A method of assembling the final reduction gear transmission according to Item 1 .