JP5278089B2 - Pinion shaft structure of final drive unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pinion shaft structure capable of shortening the overall length of a pinion shaft and achieving the reduced size and weight reduction of a final drive unit. <P>SOLUTION: A first pinion shaft 4A and a second pinion shaft 4B are connected and fixed to each other without rotation with a joint hole 7 and a joint shaft part 8 being fitted. A bearing fixing flange 10 of the second pinion shaft 4B is engaged with an end surface of a bearing 3 and latched. Thereby, an installation space for a latching retainer ring and a fixing nut becomes unnecessary on a vehicle front side of the pinion shaft 4, thus enabling the overall length of the pinion shaft 4 to be shortened. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a pinion shaft structure of a final drive unit in a vehicle such as an automobile.

  The final drive unit that transmits the driving force of the vehicle drive unit to the drive wheels includes a pinion shaft 104 provided with a hypoid pinion 105 at the terminal inside the differential case 101 as an input shaft, as shown in FIG.

  The pinion shaft 104 is generally configured as a single shaft structure in which the aforementioned hypoid pinion 105 is directly cut at one shaft end and the input shaft fitting connection portion 107 is formed at the other end. .

  A fitting / fixing portion 106 of the bearing 103 is formed in the shaft intermediate portion of the pinion shaft 104, and a unit bearing as the bearing 103 is press-fitted and fitted into the bearing fitting / fixing portion 106.

  The pinion shaft 104 is rotatably supported in the bearing hole 102 by press-fitting the bearing 103 into a bearing portion 102 a formed in a stepped manner in the bearing hole 102 of the differential case 101.

  The front end portion of the bearing fitting fixing portion 106 into which the bearing 103 is press-fitted and fitted is formed up to the vicinity of the outer opening of the bearing hole 102, and a retainer ring 108 is inserted and disposed therein. The bearing 103 is sandwiched between the hypoid pinion 105 and the molded base portion of the hypoid pinion 105, and the retainer ring 108 is clamped by a nut 110 screwed to a screw portion 109 formed adjacent to the bearing fitting fixing portion 106. Thus, the fixing of the bearing 103 is prevented.

  The retainer ring 103 also serves as a sliding portion of the oil seal 111 that seals the outer opening of the bearing hole 102, and an outer peripheral surface on which the oil seal 111 is externally fitted is used as an oil seal sliding surface 112. Has been increased.

JP 2000-232755 A

In the conventional pinion shaft structure, the pinion shaft 104 is formed as a single shaft structure as described above, and a retainer ring 108 and a nut for fixing the bearing 103 are provided on the vehicle front side of the pinion shaft 104. there is necessary to set the arrangement space of 110, the total length l ₂ of the pinion shaft 104 is long.

Further, the retainer ring 108 is indispensable in order to also serve as a sliding member of the oil seal 111. In addition to increasing the number of parts, the retaining ring 108 needs to have a thickness dimension capable of securing the oil seal sliding surface 112 having a required width. As a result, the total length l ₂ of the pinion shaft 104 is increased, which is disadvantageous in terms of weight and cost. In addition, since the oil seal sliding surface 112 is formed on the outer peripheral surface of the retainer ring 108 and the oil seal sliding surface 112 is increased in diameter, the oil seal peripheral speed is increased, and the high rotation range is naturally limited. This causes a malfunction.

  On the other hand, as shown in Patent Document 1, in the motor structure in which the hypoid pinion is provided at the tip of the motor shaft, the motor shaft is divided into two parts in the axial direction and connected by a shaft coupling. Although the basic structure of this motor structure is different from that of the final drive unit of the vehicle that is the subject of the present invention, it cannot be used as it is as the pinion shaft structure of the final drive unit.

  Therefore, the present invention provides a pinion shaft structure of a final drive unit that can be designed to be as short as possible in the overall length of the pinion shaft and eliminate the need for a retainer ring for fixing a bearing, and can be reduced in size and weight. To do.

  The pinion shaft structure of the final drive unit of the present invention is a pinion shaft in which a shaft intermediate portion is rotatably supported by a bearing hole of a differential case via a bearing, and a hypoid pinion is provided at an end portion in the differential case, The pinion shaft has a fitting fixing portion of the bearing on the outer periphery, the hypoid pinion is provided at one end, and a joint hole is formed at the center of the other end, and the first pinion at one end A joint shaft portion that is fitted in the joint hole of the shaft and is non-rotatably connected and fixed to the first pinion shaft; and an input shaft fitting connection portion at the other end; and the joint shaft portion and the input shaft fitting A second pinion shaft that integrally has a bearing fixing flange that engages with an end face of the bearing at an intermediate portion between the joint and the connecting portion. It has been a major feature that it is.

The first pinion shaft and the second pinion shaft are fitted and fixed to each other in a non-rotating manner by fitting a joint shaft portion into the joint hole, so that the bearing fixing flange of the second pinion shaft is attached to the end surface of the bearing. Engage and the bearing is secured.
An oil seal sliding surface for sealing the bearing hole of the differential case is directly formed on the second pinion shaft adjacent to the bearing fixing flange.

  According to the present invention, the first pinion shaft and the second pinion shaft are fixedly connected to each other in a non-rotating manner by fitting their joint holes and joint shaft portions, thereby fixing the bearing of the second pinion shaft. Since the flange engages with the end surface of the bearing to prevent the pinion shaft from being disposed, the space for arranging the retainer ring and the retainer ring pressing nut as described above becomes unnecessary on the vehicle front side of the pinion shaft. Can be designed as short as possible, and the final drive unit can be made compact.

Further, as described above, in addition to shortening the total length of the pinion shaft, it is possible to eliminate the need for a retainer ring having a large thickness and an outer diameter, so that the final drive unit can be reduced in weight.
In addition, since the oil seal sliding surface is directly formed on the second pinion shaft and the diameter of the oil seal sliding surface can be reduced, the peripheral speed of the oil seal can be reduced to increase the high rotation range of the final drive unit. You can also.

Sectional drawing which shows one Embodiment of the pinion shaft structure of the final drive unit which concerns on this invention. Sectional drawing which shows the pinion shaft structure in the conventional final drive unit.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of a pinion shaft structure of a final drive unit according to the present invention. An intermediate shaft portion is rotatably supported by a bearing hole 2 of a differential case 1 via a bearing 3, and an end in the differential case 1 is shown. The pinion shaft 4 provided with a hypoid pinion 5 in its part is composed of a first pinion shaft 4A and a second pinion shaft 4B which are divided into two in the axial direction.

  The first pinion shaft 4A has a bearing fitting / fixing portion 6 formed on the outer periphery thereof, and the hypoid pinion 5 is directly formed at one end, and a joint hole 7 is formed at the center of the other end. Is formed.

  A unit bearing as the bearing 3 is press-fitted into the bearing fitting fixing portion 6 in advance. The bearing fitting fixing portion 6 is set to have an axial length that is the same as or slightly shorter than the axial length of the inner race 3A of the bearing 3 that is press-fitted to the outer periphery thereof.

  The second pinion shaft 4B has a joint shaft portion 8 fitted in the joint hole 7 of the first pinion shaft 4A at one end and connected non-rotatably to the first pinion shaft 4A, and an input at the other end. A shaft fitting connection portion 9 is formed.

  In the intermediate portion between the joint shaft portion 8 and the input shaft fitting contact portion 8, the end face of the inner race 3A of the bearing 3 with the first pinion shaft 4A and the second pinion shaft 4B being connected and fixed. A bearing fixing flange 10 that engages with each other is integrally formed.

  The joint hole 7 and the joint shaft portion 8 are non-rotatably fitted and connected to each other by engagement means 11 such as spline engagement or serration engagement.

  The first pinion shaft 4A and the second pinion shaft 4B are organically coupled and fixed by an appropriate coupling means.

  In the present embodiment, the joint hole 7 of the first pinion shaft 4A is formed with a through hole 12 that opens in the end face of the hypoid pinion 5, while the joint shaft portion 8 of the second pinion shaft 4B. A small-diameter shaft extending portion 13 that is provided with a screw portion 14 at least at the end portion and is inserted and disposed in the through hole 12 is integrally provided on the end surface of the hypoid pinion 5. A nut 15 is screwed onto the 13 screw portions 14, and the first pinion shaft 4A and the second pinion shaft 4B are fastened and fixed in the axial direction.

  A counterbore 16 having a depth corresponding to the height of the nut 15 is formed around the opening of the through-hole 12 on the end face of the hypoid pinion 5, and the threaded portion 14 and the nut 15 are screwed together. The projecting portion of the fastening portion is configured to fit within the counterbore portion 16.

  Thus, the pinion shaft 1 to which the first pinion shaft 4A and the second pinion shaft 4B are connected and fixed is inserted into the bearing hole 2 from the inside of the differential case 1, and the outer race 3B of the bearing 3 is inserted into the bearing hole 2. By being press-fitted into the stepped molded bearing portion 2a, the bearing portion 2 is rotatably supported.

  The outer opening of the bearing hole 2 of the differential case 1 is sealed by an oil seal 18, but the portion corresponding to the outer opening of the bearing hole 2 of the second pinion shaft 4 </ b> B is adjacent to the bearing fixing flange 10. Then, the oil seal sliding surface 17 with high surface accuracy is formed with a required width, and the oil seal 18 is externally attached to the oil seal sliding surface 17.

According to the pinion shaft structure of the final drive unit of the present embodiment having the above-described configuration, the first pinion shaft 4A and the second pinion shaft 4B are fitted to the joint hole 7 and the joint shaft portion 8. Since the bearing fixing flange 10 of the second pinion shaft 4B engages with the end surface of the inner race 3A of the bearing 3 to prevent it from being pulled out by connecting and fixing to each other in a non-rotating manner, The space for arranging the retainer ring 108 and the nut 110 as in the above structure becomes unnecessary.

As a result, the total length l ₁ of the pinion shaft 4 can be designed as short as possible, and the final drive unit can be made compact.

Further, along with reduction in the total length l ₁ of the pinion shaft 4 as described above, for a large the retainer ring 108 of the thickness and outer diameter can be omitted, it is possible to reduce the weight of the final drive unit In addition, the cost can be advantageously obtained.

  Here, in the present embodiment, the axial extension formed on the end surface of the joint shaft portion 8 of the second pinion shaft 4B is inserted into the through hole 12 provided continuously to the joint hole 7 of the first pinion shaft 4A. The projecting portion 13 is inserted, and a nut 15 is screwed into a screw portion 14 formed at the end of the shaft so that the first pinion shaft 4A and the second pinion shaft 4B are axially connected to the end surface side of the hypoid pinion 5 in the axial direction. Since the fastening and fixing are performed, the fastening and fixing means for the first pinion shaft 4A and the second pinion shaft 4B can be easily designed without difficulty in structure.

  In addition, since the protrusion of the threaded fastening portion between the screw portion 14 and the nut 15 is accommodated in a counterbore portion 16 formed on the end face of the hypoid pinion 5, the space occupied by the hypoid pinion 5 in the differential case 1 and the pinion There is no slight effect on shortening the overall length of the shaft 4.

  Further, since the oil seal sliding surface 17 is formed directly on the second pinion shaft 4B and the diameter of the oil seal sliding surface 17 can be reduced, the peripheral speed of the oil seal 18 is reduced and the final drive unit has a high rotational speed range. Can also be expanded.

  In the embodiment, the first pinion shaft 4A and the second pinion shaft 4B are connected to each other by screwing the screw portion 14 of the shaft extension portion 13 of the joint shaft portion 8 and the nut 15 on the end surface side of the hypoid pinion 5. The second pinion shaft 4B is formed by penetrating a bolt insertion hole in the axial direction, and the first pinion shaft 4A and the second pinion shaft 4B are connected to each other within the end surface of the second pinion shaft 4B on the vehicle front side. It is also possible to fasten and fix the pinion shaft 4B in the axial direction with a fixing bolt.

  Further, as a means for fixing the first pinion shaft 4A and the second pinion shaft 4B, in addition to the axial fastening structure by the bolt and nut, the diameter of the fitting portion between the joint hole 7 and the joint shaft portion 8 by a cotter pin or the like is used. It is also possible to organically bond and fix in the direction.

DESCRIPTION OF SYMBOLS 1 ... Differential case 2 ... Bearing hole 3 ... Bearing 4 ... Pinion shaft 4A ... 1st pinion shaft 4B ... 2nd pinion shaft 5 ... Hypoid pinion 6 ... Bearing fitting fixing part 7 ... Joint hole 8 ... Joint shaft part 9 ... Input shaft Fitting connection part 10 ... bearing fixing flange 12 ... through hole 13 ... shaft extension part 14 ... screw part 15 ... nut 16 ... counterbore part 17 ... oil seal sliding surface 18 ... oil seal

Claims (3)

An intermediate shaft portion is rotatably supported in a bearing hole of a differential case via a bearing, and is a pinion shaft provided with a hypoid pinion at an end in the differential case,
The pinion shaft has a fitting fixing portion of the bearing on the outer periphery, the hypoid pinion is provided at one end, and a first pinion shaft having a joint hole formed at the other end center portion;
A joint shaft portion fitted into a joint hole of the first pinion shaft at one end and connected and fixed non-rotatably to the first pinion shaft, and an input shaft fitting connection portion at the other end, and these joints A second pinion shaft integrally having a bearing fixing flange that engages with an end surface of the bearing at an intermediate portion between the shaft portion and the input shaft fitting connection portion ;
The first pinion shaft and the second pinion shaft are fixedly connected to each other in a non-rotating manner by fitting the joint shaft portion into the joint hole so that the bearing fixing flange of the second pinion shaft is the bearing. Engaging the end face of the
A pinion shaft structure of a final drive unit, wherein the second pinion shaft is directly formed with an oil seal sliding surface that seals the bearing hole of the differential case adjacent to the bearing fixing flange . While the joint hole of the first pinion shaft is continuously provided with a through hole that opens in an end surface of the hypoid pinion,
The end surface of the joint shaft portion of the second pinion shaft is integrally provided with a shaft extending portion that is provided with a threaded portion at least at the end portion and is inserted and disposed in the through hole. The pinion shaft structure of the final drive unit according to claim 1, wherein the first pinion shaft and the second pinion shaft are fastened and fixed by screwing a nut onto the thread portion of the extending portion. The pinion shaft of the final drive unit according to claim 2, wherein a counterbore portion having a depth corresponding to the height of the nut is formed on an end surface of the hypoid pinion around the opening of the through hole. Construction.

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