JP7233151B2 - Differential gear and its assembly method - Google Patents

Description

The present invention relates to a differential and its assembly method.

A final reduction gear of an automobile is generally arranged substantially in the center between the left and right rear wheels. The power generated by the prime mover in front of the vehicle body is decelerated by the transmission, transmitted to the final reduction gear via the propulsion shaft, decelerated again by the final reduction gear and distributed to the left and right rear wheels. The final reduction gear includes a drive pinion gear that rotates integrally with the propulsion shaft, a differential that includes a ring gear that meshes with the drive pinion gear at right angles, and a housing that accommodates the differential. The differential gear consists of a differential case that rotates together with the ring gear, a side gear that rotates together with the drive shaft, a pinion gear that meshes with the side gear, and a pinion shaft that is inserted into the hole of the pinion gear and fitted into the insertion hole of the differential case. It is configured.

The pinion gear is rotatably supported on the pinion shaft. The back surfaces of the pinion gear and the side gear are spherical and are in sliding contact with the inner surface of the differential case. Therefore, at these sliding contact points, that is, the sliding contact portion between the hole of the pinion gear and the outer peripheral surface of the pinion shaft, the sliding contact portion between the back surface of the pinion gear and the inner surface of the differential case, and the sliding contact portion between the back surface of the side gear and the inner surface of the differential case. It is necessary to lubricate by supplying lubricating oil. However, since the differential case is a rotating body, there is a problem that it is difficult to efficiently supply lubricating oil to the inside of the rotating differential case.

In addition, when a window is formed on the outer peripheral surface of the differential case to incorporate the pinion gear, the side gear, and the pinion shaft, there is a problem that the lubricating oil that has flowed into the differential case flows out through the window due to the action of centrifugal force. be.

On the other hand, Patent Documents 1 to 3 describe techniques for storing lubricating oil in a differential case. U.S. Pat. No. 6,200,000 describes attaching an inwardly directed lubricating oil retaining lip to the edge of the window. Patent Document 2 describes that a differential case is provided with a lubricating oil reservoir having a variable volume. Patent Document 3 describes that a cover member having a lubricating oil inlet is attached to the outside of the differential case.

JP 2008-128265 A JP-A-2000-297828 Japanese Utility Model Laid-Open No. 5-42811

However, in the techniques of Patent Documents 1 to 3, the structure of the constituent members is complicated, and the structure is unsuitable for suppressing the outflow of lubricating oil from the window.

An object of the present invention is to provide a technique for storing lubricating oil inside a differential case with a simple structure.

In order to solve the above-mentioned problems, the present invention provides a pair of pinion gears, a pair of side gears meshing with the pinion gears, a differential case formed with windows for incorporating the pinion gears and the side gears, and a back surface of the side gears and the differential case. and a washer arranged between the window and the inner surface, wherein the washer is provided with a closing wall portion that closes the window portion.

According to the present invention, it is possible to suppress the lubricating oil in the differential case from flowing out through the window with a simple structure using a washer.

Further, according to the present invention, the washer is composed of a single spherical member having a pair of side gear through-holes through which the shaft of the side gear is passed, and the closing wall portion extends from one side gear through-hole to the other side gear. It is characterized by being a wall extending into the through hole.

According to the present invention, one washer can be used for two side gears, so that the number of parts can be reduced and the assembly work can be simplified.

In the present invention, the washer includes a pair of washer base portions arranged between the back surface of the side gear and the inner surface of the differential case and having the side gear through hole formed in the center, and A pair of pinion gear enclosing portions formed in an arc shape is provided, and a slit extending between the pair of pinion gear enclosing portions is formed.

According to the present invention, even if the washer is larger than the window of the differential case, the slit can be contracted to reduce the diameter of the washer so that it can be passed through the window.

Further, the present invention provides a pair of pinion gears, a pair of side gears meshing with the pinion gears, a differential case formed with windows for incorporating the pinion gears and the side gears, and between the rear surface of the side gears and the inner surface of the differential case. A method for assembling a differential gear comprising: a washer having a washer base portion arranged and having a side gear through-hole formed in the center; and a blocking wall portion extending from the washer base portion and blocking the window portion, the method comprising: a washer assembling step of assembling the washer into the differential case through the window, aligning the side gear through-hole with the rotational axis of the differential case, and temporarily shifting the blocking wall from the window; A gear assembling step of assembling the side gear and the pinion gear into the differential case, passing the shaft portion of the side gear through the side gear through-hole and pivotally supporting the differential case, and rotating the washer around the rotation axis of the differential case. and a step of closing the window with the closing wall.

According to the present invention, the washer, the pinion gear, and the side gear can be quickly and easily incorporated into the differential case, and then the window of the differential case can be closed with the washer.

Further, according to the present invention, the washer is composed of a single spherical member having a pair of pinion gear surrounding portions arcuately formed from the end portion of the washer base portion, and the pair of pinion gear surrounding portions In the washer assembling step, the slit is shrunk, and the washer is passed through the window while being reduced in diameter by elastic deformation.

According to the present invention, even if the washer is larger than the window of the differential case, the slit can be contracted to reduce the diameter of the washer so that it can be passed through the window.

Further, the present invention includes a pair of pinion gears, a pinion shaft that is inserted through the insertion holes of the pinion gears, a pair of side gears that mesh with the pinion gears, a shaft insertion hole that the pinion shafts are inserted into, the pinion gears and the side gears. and a differential case formed with a window portion to be incorporated, wherein the pair of pinion gears includes a dummy shaft having a first engaging portion formed of a conical concave portion or convex portion on the end face. a gear assembling step of assembling the side gear and the pinion gear into the differential case through the window portion in a state in which the is inserted; At least one shaft having, on its end surface, a second engaging portion formed of a conical projection or recess for engagement is inserted into the shaft fitting hole, and the first engaging portion and the second engaging portion are engaged. and an alignment step of aligning the shaft fitting hole and the insertion hole by aligning them.

According to the present invention, the insertion hole of the pinion gear and the shaft insertion hole of the differential case can be easily aligned, and the pinion shaft can be smoothly attached to the differential case.

Further, in the present invention, the at least one shaft is a second dummy shaft, and the dummy shaft removing step of inserting the pinion shaft into the shaft insertion hole and pushing out the dummy shaft and the second dummy shaft from the differential case. characterized by performing

According to the present invention, the first dummy shaft and the second dummy shaft can be accurately aligned, and the pinion shaft can be used to easily remove the first dummy shaft and the second dummy shaft.

According to the present invention, lubricating oil can be efficiently held inside the differential case with a simple structure.

1 is a plan sectional view of a differential gear of a first embodiment; FIG. It is a II-II sectional view in FIG. 1 is an exploded perspective view of a differential gear of a first embodiment; FIG. It is a plane sectional view of the differential gear of 2nd Embodiment. FIG. 5 is a cross-sectional view taken along line V-V in FIG. 4; FIG. 7 is an exploded perspective view of the differential gear of the second embodiment; It is explanatory drawing of the assembly method of a differential gear, and shows the state which diameter-reduces a washer and incorporates it. FIG. 4 is an explanatory diagram of a method of assembling the differential, showing a state in which the washer is restored in the differential case; FIG. 4 is an explanatory diagram of a method of assembling the differential, showing a state in which a pinion gear and side gears are incorporated; FIG. 10 is an explanatory diagram of a method of assembling the differential, showing a state in which the washer, pinion gear, and side gear are rotated approximately 90 degrees from the state shown in FIG. 9; FIG. 4 is an explanatory diagram of a method of assembling the differential, showing a state in which the first dummy shaft is inserted into the pinion gear; FIG. 12 is an explanatory diagram of a method of assembling the differential, showing a state in which the pinion gear is rotated approximately 90 degrees from the state in FIG. 11; FIG. 4 is an explanatory diagram of a method of assembling the differential, showing a state in which the first dummy shaft and the second dummy shaft are engaged; FIG. 4 is an explanatory diagram of a method of assembling the differential, showing a state in which the pinion shaft pushes out the first dummy shaft and the second dummy shaft; FIG. 4 is an explanatory diagram of a method of assembling the differential, showing a state where the pinion shaft is attached to the differential case;

"First Embodiment"
A first embodiment will be described with reference to FIGS. 1 to 3. FIG. The differential gear 1 is incorporated in, for example, a final reduction gear mounted on an FF-based four-wheel drive vehicle. The final reduction gear decelerates and deflects the rotational motion of a drive pinion shaft (not shown) extending in the longitudinal direction by 90° to convert it into rotational motion about a first axis O1 extending in the lateral direction to drive the left and right rear wheels. to

1 and 2, the differential gear 1 includes a pinion shaft 3, a pair of pinion gears 4, a pair of side gears 5, a pair of washers 6, a differential case 2 containing them, and a differential case 2 that rotates integrally. and a ring gear (not shown). The ring gear is a ring-shaped bevel gear that meshes with a drive pinion gear (not shown) of the drive pinion shaft, and is fastened to the flange portion 2C of the differential case 2 with bolts (not shown).

The differential case 2 is a rotating body that rotates about the first axis O1, and includes a body portion 2A, left and right boss portions 2B, 2B, and a flange portion 2C. A pair of rectangular windows 7 for incorporating the pinion gear 4 and the side gear 5 are formed on the outer peripheral surface of the body portion 2A with the first axis O1 interposed therebetween. Shaft insertion holes 8, 8 for supporting the pinion shaft 3 are formed in the body portion 2A along a direction of a second axis O2, which is an axis orthogonal to the first axis O1 and passing through the first axis O1. ing. Around the shaft fitting holes 8, 8 on the inner surface of the body portion 2A, a concave spherical sliding contact surface 2D is formed to slide against the spherical back surface 4A of the pinion gear 4. As shown in FIG.

The flange portion 2C is formed so as to extend radially outward from the outer peripheral surface of the body portion 2A near one end. The left and right boss portions 2B have a cylindrical shape extending from the left and right sides of the body portion 2A about the first axis O1, and are supported by a housing (not shown) of the final reduction gear via bearings. A drive shaft (not shown) connected to the left rear wheel or the right rear wheel is inserted through the inside of the boss portion 2B.

Both ends of the pinion shaft 3 are fitted into the shaft fitting holes 8, so that the pinion shaft 3 is arranged inside the body portion 2A centering on the second axis O2. An insertion hole 4B is formed in the pinion gear 4, and the pinion gear 4 rotates with respect to the pinion shaft 3 inserted through the insertion hole 4B. The side gear 5 is spline-connected to a drive shaft (not shown). The side gears 5 are arranged on both sides of the pinion gear 4, mesh with the pinion gear 4, and rotate about the first axis O1. A shaft portion 5B of the side gear 5 is supported by a side gear shaft support hole 2E of the differential case 2 .

1 to 3, the pair of washers 6 are arranged between the back surface 5A of each side gear 5 and the inner surface of the differential case 2 facing the back surface 5A (side gear facing inner surface 2F). The rear surface 5A of the side gear 5 has a spherical shape, and following this, the side gear facing inner surface 2F has a concave spherical shape. The washer 6 is positioned between the back surface 5A of the side gear 5 and the inner surface 2F facing the side gear, and has an annular washer base portion 10 formed in the center thereof with a side gear through-hole 9 for passing the shaft portion 5B of the side gear 5, and a washer base portion. A closing wall portion 11 extending from 10 in the radially outward direction of the first axis O1 toward the other washer 6 side and closing the window portion 7 from the inside of the differential case 2 is provided.

The washer base portion 10 has a spherical shape following the rear surface 5A of the side gear 5 and the side gear facing inner surface 2F, and the blocking wall portion 11 is also formed in a spherical shape with the same curvature as the washer base portion 6A. In this embodiment, the washer 6A on one side and the washer 6B on the other side have the same shape, and are arranged symmetrically about the first axis O1. Therefore, one washer 6A closes one window 7, and the other washer 6B closes the other window 7. As shown in FIG. By forming the washer 6A and the washer 6B into the same shape, it is possible to share parts. The washer 6 may be made of a resin material, or may be made of a metal material such as a heat-treated steel plate.

As shown in FIG. 3, substantially semicircular pinion gear surrounding portions 12 are formed at both ends of the washer 6 in the direction of the second axis O2 to avoid interference with the pinion gear 4 . An edge portion 12A of the pinion gear enclosing portion 12 is formed in a generally arcuate shape around the second axis O2. For example, the edge 12A surrounds the outer periphery of the pinion gear 4, so that the washer 6 is attached so as not to rotate about the first axis O1, and the closing wall 11 keeps the window 7 closed. In addition, as a rotation stop for the washer 6, uneven engagement between the washer 6 and the inner surface of the differential case 2 may be used.

As described above, if the washer 6 is arranged between the rear surface 5A of the side gear 5 and the inner surface 2F facing the side gear of the differential case 2, and the washer 6 is provided with the closing wall portion 11 that closes the window portion 7, the inside of the differential case 2 can be can be suppressed from flowing out of the lubricating oil from the window portion 7. As a result, the lubricating oil holding performance in the differential case 2 is improved with a simple structure, and the lubrication of the gears is maintained well.

"Second Embodiment"
A second embodiment will be described with reference to FIGS. 4 to 6. FIG. In the first embodiment, two washers 6A and 6B are arranged as washers 6 for the two side gears 5, but in the second embodiment, one washer 60 is arranged for the two side gears 5. . Other constituent elements are the same as those of the first embodiment, and are denoted by the same reference numerals, and detailed description thereof will be omitted.

The washer 60 is composed of one spherical member having a pair of side gear through-holes 62 through which the shaft portion 5B of the side gear 5 is passed. A hole-surrounding portion of the side gear through hole 62 is arranged between the rear surface 5A of the side gear 5 and the side gear facing inner surface 2F of the differential case 2 to form a washer base portion 63 . A pair of pinion gear surrounding portions 61 are formed in an arc shape from an end portion of the washer base portion 63 . A wall portion extending from one side gear through-hole 62 to the other side gear through-hole 62, that is, extending from one washer base portion 63 to the other washer base portion 63 is a blocking wall that blocks the window portion 7 of the differential case 2. A part 64 is constructed. Further, the washer 60 is formed with a slit 65 extending between the pair of pinion gear surrounding portions 61 .

Also with the washer 60 of the second embodiment, the blocking wall portion 64 can prevent the lubricating oil in the differential case 2 from flowing out from the window portion 7 . As a result, the lubricating oil holding performance in the differential case 2 is improved with a simple structure, and the lubrication of the gears is maintained well. By using one member for the washer 60 for the two side gears 5, the number of parts can be reduced and the assembly work can be simplified. The washer 60 may be made of a resin material, or may be made of a metal material such as a heat-treated steel plate.

<How to assemble the differential gear>
A method of assembling the differential gear 1 will be described with reference to FIGS. 7 to 10, taking the differential gear 1 of the second embodiment as an example.

"Washer incorporation process C1"
As shown in FIG. 7 , first, the washer 60 is assembled into the differential case 2 through the window portion 7 . When the window portion 7 is small, the slit 65 is contracted, and the washer 60 is passed through the window portion 7 in a state where the diameter of the washer 60 is reduced by elastic deformation. As shown in FIG. 8 , inside the differential case 2 , the washer 60 returns to its original shape due to the elastic restoring force and contacts the inner surface of the differential case 2 . At this time, the side gear through-hole 62 is aligned with the first axis O1, and the blocking wall portion 64 is positioned deviated from the window portion 7 . That is, the blocking wall portion 64 is positioned so as to block the shaft insertion hole 8 , and the pinion gear surrounding portion 61 of the washer 60 communicates with the window portion 7 .

"Gear assembly process C2"
Next, as shown in FIG. 9 , the side gear 5 and the pinion gear 4 are assembled into the differential case 2 through the window portion 7 . Since the pinion gear surrounding portion 61 of the washer 60 is in communication with the window portion 7, the side gear 5 and the pinion gear 4 can be assembled in the washer 60 without any problem. Then, after passing the shaft portion 5B of the side gear 5 through the side gear through hole 62 of the washer 60, the side gear shaft support hole 2E of the differential case 2 is pivotally supported. The pinion gear 4 meshes with the side gear 5 while being positioned within the pinion gear surrounding portion 61 of the washer 60 .

"Window part closing process C3"
Next, as shown in FIG. 10, the washer 60 and the gears are rotated about 90 degrees about the rotation axis O1, and the closing wall portion 64 closes the window portion 7. Next, as shown in FIG. Since the insertion hole 4B (FIG. 4) of the pinion gear 4 coincides with the shaft insertion hole 8 of the differential case 2, the pinion shaft 3 is inserted through the shaft insertion hole 8 and the pinion gear 4 is pivotally supported.

According to the assembly method described above, the washer 60 , the pinion gear 4 , and the side gear 5 can be quickly and easily incorporated into the differential case 2 , and the window 7 of the differential case 2 can be closed with the washer 60 . The above assembly method can also be applied to the washer 6 of the first embodiment.

Here, in the window portion closing step C3, when the washer 60 is rotated to close the window portion 7, the insertion hole 4B of the pinion gear 4 and the shaft insertion hole 8 of the differential case 2 are inserted so that the pinion shaft 3 can be inserted. must be aligned with high precision. However, since the window portion 7 is already closed by the washer 60, it is impossible to insert the hand into the differential case 2 through the window portion 7 for alignment, making delicate position adjustment difficult.

To solve this problem, as shown in FIGS. 11 to 15, the insertion hole 4B of the pinion gear 4 and the shaft insertion hole 8 of the differential case 2 can be easily aligned by performing the following steps.

"Gear assembly process C2a"
11, the side gear 5 and the pinion gear 4 are assembled into the differential case 2 through the window portion 7. As shown in FIG. A difference from the gear assembling step C2 described above is that the first dummy shaft 21 is inserted between the pair of pinion gears 4 . The length of the first dummy shaft 21 is such that the end of the first dummy shaft 21 does not protrude from the back surface 4A of the pinion gear 4 when the pinion gear 4 and the side gear 5 are in mesh. At the center of the end face of the first dummy shaft 21, a first engagement portion 22 is formed which is a conical concave portion.

"Positioning process C4"
Next, as shown in FIG. 12, the washer 60 is rotated in the window closing step C3 so that the end face of the first dummy shaft 21 faces the shaft fitting hole 8. As shown in FIG. Next, as shown in FIG. 13, the second dummy shaft 23 is inserted into the shaft insertion hole 8. Then, as shown in FIG. At the center of the end surface of the second dummy shaft 23 , a second engaging portion 24 is formed which is a conical convex portion that engages with the first engaging portion 22 . Even if the insertion hole 4B of the pinion gear 4 and the shaft insertion hole 8 of the differential case 2 are misaligned at the stage of FIG. 12, the first engaging portion 22 and the second engaging portion 24 are formed conically. Therefore, there is no catching between the two at the initial stage of engagement. Then, when the first engaging portion 22 and the second engaging portion 24 are engaged with each other, the guiding action of the conical surfaces of the first engaging portion 22 and the second engaging portion 24 causes the insertion hole 4B of the pinion gear 4 to move toward the shaft. It is aligned with the fitting hole 8 . In addition, the first engaging portion 22 side may be a convex portion, and the second engaging portion 24 side may be a concave portion.

The insertion hole 4B of the pinion gear 4 and the shaft insertion hole 8 can also be aligned by inserting the second dummy shaft 23 into only one of the two shaft insertion holes 8 . However, if the second dummy shafts 23 are inserted into both of the two shaft insertion holes 8 as shown in FIG. It can be easily understood that the first engaging portion 22 and the second engaging portion 24 are reliably engaged and the insertion hole 4B of the pinion gear 4 and the shaft insertion hole 8 are accurately aligned.

"Dummy shaft removal process C5"
Next, as shown in FIG. 14, the pinion shaft 3 is fitted into the shaft fitting hole 8, the first dummy shaft 21 and the second dummy shaft 23 are pushed out from the differential case 2, and the pinion shaft 3 is pushed out as shown in FIG. Install properly to the differential case 2.

In the above description, alignment was performed using the second dummy shaft 23 . However, alignment may be performed by engaging the first dummy shaft 21 and the pinion shaft 3 by providing the second engaging portion 24 on the end surface of the pinion shaft 3 without using the second dummy shaft 23 . . In particular, as an example of the pinion shaft 3, there is a case where an oil passage for guiding lubricating oil to the inside of the differential case 2 is formed, and a conical hole mouth is formed in the end surface of the pinion shaft 3 as an opening of this oil passage. . Therefore, by using this conical hole mouth, the insertion hole 4B of the pinion gear 4 and the shaft fitting hole 8 of the differential case 2 can be aligned.

According to the assembly method described above, the insertion hole 4B of the pinion gear 4 and the shaft insertion hole 8 can be easily aligned, and the pinion shaft 3 can be smoothly attached to the differential case 2 . This assembly method can be performed regardless of the presence or absence of washers 6 and 60.

1 differential gear 2 differential case 3 pinion shaft 4 pinion gear 5 side gear 6 washer 7 window 8 shaft insertion hole 9 side gear through hole 10 washer base portion 11 blocking wall portion 12 pinion gear surrounding portion 21 first dummy shaft 22 first engaging portion 23 Second dummy shaft 24 Second engaging portion 60 Washer 61 Pinion gear enclosing portion 62 Side gear through hole 63 Washer base portion 64 Closing wall portion 65 Slit

Claims (2)

a pair of pinion gears;
a pair of side gears meshing with the pinion gear;
a differential case formed with a window for incorporating the pinion gear and the side gear;
a washer disposed between the back surface of the side gear and the inner surface of the differential case;
with
The washer is provided with a blocking wall portion that blocks the window portion and suppresses the lubricating oil in the differential case from flowing out from the window portion ,
The washer is composed of a single spherical member having a pair of side gear through-holes through which the shaft of the side gear passes,
The blocking wall portion is a wall portion extending from one side gear through-hole to the other side gear through-hole,
The washer comprises a pair of washer base portions arranged between the back surface of the side gear and the inner surface of the differential case and having the side gear through hole formed in the center, and an arcuate shape extending from the end portion of the washer base portion. a pair of pinion gear surroundings,
A slit extending between the pair of pinion gear enclosing portions is formed.
A differential device characterized by: a pair of pinion gears;
a pair of side gears meshing with the pinion gear;
a differential case formed with a window for incorporating the pinion gear and the side gear;
a washer base portion disposed between the back surface of the side gear and the inner surface of the differential case and having a side gear through hole formed in the center; A washer having a blocking wall portion that suppresses outflow from the portion;
A method of assembling a differential comprising:
a washer assembling step of assembling the washer into the differential case through the window, aligning the side gear through-hole with the rotational axis of the differential case, and temporarily shifting the blocking wall from the window;
a gear assembling step of assembling the side gear and the pinion gear into the differential case through the window portion, passing the shaft portion of the side gear through the side gear through-hole, and pivotally supporting the differential case;
a window closing step of rotating the washer around the rotation axis of the differential case and closing the window with the closing wall;
and
The washer is composed of a single spherical member provided with a pair of pinion gear enclosing portions formed in an arc shape from an end portion of the washer base portion, and is formed with a slit extending between the pair of pinion gear enclosing portions. ,
In the washer assembling step, the slit is contracted, and the washer is passed through the window while being reduced in diameter by elastic deformation.
A method of assembling a differential, characterized by:

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