JP2008169922A - Differential device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a differential device, in which retainers for bearings, even against a differential oil, maintain strength without deterioration, are excellent in durability, and can stably retain balls to keep smooth rolling, and in which rolling resistance can be reduced. <P>SOLUTION: The differential device comprises a differential case 51, a differential deceleration mechanism 52 arranged in the differential case 51, a pinion gear 54 engaged with a ring gear 53 of the differential deceleration mechanism 52, a pinion shaft 55 for supporting the pinion gear 54, and bearings 56 and 57 for rotatably supporting the pinion shaft 55 in the differential case 51. The bearings 56 and 57 are tandem double-row angular contact ball bearings, respectively. The retainers 19 and 20 of the bearings 56 and 57 are pressed retainers formed by pressing of a rolled steel plate, respectively. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a differential apparatus.

  As the bearing, there is an angular ball bearing capable of applying a radial load and an axial load in one direction. The ball and the inner ring / outer ring have a contact angle. The larger the contact angle, the greater the load capacity of the axial load, and the smaller the contact angle, the more advantageous for high-speed rotation.

  By the way, in order to reduce rolling resistance, there is a double row angular contact ball bearing (tandem type) as an alternative to the tapered roller bearing (Patent Document 1). In addition, there is one in which this tandem type double row angular ball bearing is used for an automobile transfer (Patent Document 2). A transfer is a 4WD vehicle that transmits the power coming from the transmission to the front and rear wheels. Usually, a differential device (differential device) is also built in. I'm calling. A double row angular contact ball bearing is a structure in which a single row angular contact ball bearing is combined on the back and the inner ring and outer ring are integrated into one body, so that it can load an axial load in both directions, and has a load capacity for moment load. It is a certain bearing.

  As shown in FIG. 3, the tandem type double-row angular ball bearing includes an inner ring 2 having double-row raceway surfaces 1a and 1b, and double-row raceway surfaces 3a and 3b corresponding to the raceway surfaces 1a and 1b of the inner ring 2. And an outer ring 4 and double-row ball groups 5 and 6 interposed between the raceways 1a, 1b, 3a and 3b of each row of the inner ring 2 and the outer ring 4. The double row ball groups 5 and 6 have different pitch circle diameters. The balls 7 and 8 of the ball groups 5 and 6 are held by cages 9 and 10 disposed between the inner ring 2 and the outer ring 4.

  As shown in FIG. 4, the differential device described in Patent Document 2 includes a differential case 101, a differential reduction mechanism (not shown) disposed in the differential case 101, and a ring gear (see FIG. And a pinion shaft 105 that supports the pinion gear 104. The pinion shaft 105 is rotatably supported in the differential case 101 via bearings 106 and 107.

  And tandem type double row angular contact ball bearings are used for the bearings 106 and 107, respectively. One bearing 106 disposed on the pinion gear 104 side has a large-diameter side end surface 2a of the inner ring 2 (an end surface protruding to the pinion gear 104 side from the outer ring 4) press-contacts the end surface 104a of the pinion gear 104, and The end surface 4 a on the side opposite to the pinion gear is in pressure contact with a step surface 108 formed on the inner surface of the case 101.

  The other bearing 107 has a large-diameter side end surface 2a of the inner ring 2 (an end surface protruding to the side opposite to the pinion gear from the outer ring 4) press-contacts the end edge 100a of the pinion flange 100, and an end surface 4a of the outer ring 4 on the pinion gear side. The step 101 is in pressure contact with the step surface 109 formed on the inner surface of the case 101. Further, the pinion shaft 105 has a large diameter on the pinion gear 104 side to form a stepped portion 105a, and a sleeve 110 is interposed between the stepped portion 105a and the inner ring 2 of the other bearing 107.

In this case, a preload is applied to the bearings 106 and 107 via the pinion flange 100 by screwing a nut member (not shown) to the threaded portion 111 at the end of the pinion shaft 105. That is, by applying preload to the bearings 106 and 107, the rigidity of the bearing support structure is increased, the position of the pinion shaft 105 is stabilized, and the meshing with the ring gear is improved.
Patent No. 181547 JP 2004-183745 A

  Incidentally, the cage of the bearing has a role of preventing high speed rotation while preventing the rolling elements from coming off the bearing and holding the rolling elements at equal intervals in the bearing to prevent contact between the rolling elements. In addition, the cage includes punching cages (cage made by pressing), machined cages (cage made by machining), and plastic molded cages (resin holding). There is also a container.

  A resin cage is used as a bearing cage in the differential device described in Patent Document 2. The resin holder can be mass-produced by injection molding. For this reason, it has been widely used in recent years. However, the oil (differential oil) used for the differential device contains phosphorus (P) and sulfur (S). For this reason, when a resin retainer is used in differential oil, P or S may enter the resin material, which may cause a decrease in strength.

  In view of the above problems, the bearing retainer of the present invention does not decrease in strength even for differential oil, has excellent durability, can stably hold the ball, and can smoothly roll. A differential device that can be maintained and that can reduce rolling resistance is provided.

  A differential device according to the present invention includes a differential case, a differential reduction mechanism disposed in the differential case, a pinion gear meshing with a ring gear of the differential reduction mechanism, a pinion shaft that supports the pinion gear, and the differential pinion shaft. A differential device comprising a bearing rotatably supported in a case, the bearing comprising an inner ring having a double row raceway surface, and an outer ring having a double row raceway surface corresponding to the raceway surface of the inner ring, A tandem double-row angular ball having a double-row ball group interposed between the raceway surfaces of the inner ring and the outer ring with different pitch circle diameters and a cage for holding the balls of the ball group The bearing is a press cage in which a rolled steel plate is formed by press forming.

  According to the differential device of the present invention, since the bearing is a tandem double row angular ball bearing, the rolling resistance can be reduced. Moreover, since the bearing retainer is a press retainer configured by press forming a rolled steel plate, phosphorus and sulfur contained in the differential oil do not enter the retainer.

  The rolled steel plate may be a cold rolled plate or a hot rolled plate. Here, rolling refers to a plastic working process in which a raw material is passed between two rolls rotating in opposite directions to reduce the cross-sectional area to a required shape such as a plate, bar, wire, or profile. In addition, there are hot rolling that heats the material and cold rolling that passes between rolls at room temperature.

  In the differential device of the present invention, the bearing retainer does not decrease in strength even with respect to the differential oil, has excellent durability, can stably hold the ball, and maintains smooth rolling. Can do. Moreover, since this bearing is a tandem angular contact ball bearing, the rolling resistance can be reduced, and a high-quality differential device can be provided.

  In rolling, the material is compressed by a roll and the cast structure is destroyed, so that uniform and excellent properties are obtained. For this reason, the cage | basket comprised with a rolled sheet has the advantage that it is more efficient than forging, and its production cost is low. In addition, hot rolling becomes a steel material having a tough structure with a required shape, and cold rolling can achieve thinness, high dimensional accuracy, and mechanical properties that cannot be obtained hot.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows a differential device according to the present invention. This differential device includes a differential case 51, a differential reduction mechanism 52 disposed in the differential case 51, and a pinion gear meshing with a ring gear 53 of the differential reduction mechanism 52. 54 and a pinion shaft 55 that supports the pinion gear 54, and the pinion shaft 55 is rotatably supported in the differential case 51 via bearings 56 and 57.

  As the bearings 56 and 57, tandem double-row angular ball bearings shown in FIG. 1 are used. The bearings 56 and 57 respectively include an inner ring 12 having double-row raceway surfaces 11a and 11b, an outer ring 14 having double-row raceway surfaces 13a and 13b corresponding to the raceway surfaces 11a and 11b of the inner ring 12, the inner ring 12 and A double-row ball group 15, 16 interposed between the raceway surfaces 11 a, 11 b, 13 a, 13 b of each row of the outer ring 14 is provided. The ball groups 15 and 16 have different pitch circle diameters D1 and D2, respectively. In this case, D1> D2.

  The inner ring 12 has a first cutout portion 21 formed on the outer diameter surface thereof, and a second cutout portion 22 formed in the first cutout portion 21. The end of the first notch 21 opposite to the second notch is the track surface 11a, and the second notch 22 is the track 11b. Further, a circumferential groove 23 is formed on the first notch 21 on the second notch 22 side.

  The outer ring 14 has a first notch 24 formed on the inner diameter surface thereof, and a second notch 25 is formed in the first notch 24. The end of the first notch 24 opposite to the second notch is the track surface 13b, and the second notch 25 is the track 13a.

  The ball groups 15 and 16 are held by holders 19 and 20, respectively. The cages 19 and 20 are press cages obtained by processing a cold rolled plate (SPCC) by press molding. Here, the SPCC has C (carbon) of 0.15% by weight or less, Mn (manganese) of 0.60% by weight or less, P (phosphorus) of 0.100% by weight or less, and S (sulfur) of 0.050. It is a low-carbon steel with a weight percentage of less.

  The cages 19 and 20 may be press cages obtained by processing a hot rolled plate (SPHC) by press molding. SPHC is a hot-rolled soft steel sheet having 0.08 mass% C, 0.24 mass% Mn, 0.02 mass% P, 0.02% S, and the balance Fe.

  The retainers 19 and 20 include a flat plate ring-shaped base 30 and a peripheral wall 31 extending so as to expand from the outer diameter side of the base 30, and are disposed on the peripheral wall 31 at a predetermined pitch along the circumferential direction. A pocket 32 is formed. Balls 27 and 28 constituting ball groups 15 and 16 are held in the pockets 32 of the cages 19 and 20, respectively. Note that the base 30 of the large-diameter side retainer 19 corresponds to the circumferential groove 23 of the inner ring 12.

  One of the bearings 56 disposed on the pinion gear 54 side is in contact with the end portion 33 of the inner ring 12 of the bearing 56, that is, the end surface 12a, on the end surface 54a of the pinion gear 54 of the pinion shaft 55, and the end surface of the outer ring 14 on the side opposite to the pinion gear. 14 a is in pressure contact with a step surface 58 formed on the inner surface of the case 51.

  In the other bearing 57, the end portion 33 of the inner ring 12, that is, the end surface 12 a (the end surface on the opposite flange side) is pressed against the end edge 50 a of the pinion flange 50, and the end surface 14 a of the outer ring 14 on the pinion gear side is on the inner surface of the case 51. It is in pressure contact with the formed step surface 59. A sleeve 60 is interposed between the one bearing 56 and the inner ring 12 of the other bearing 57.

  In this case, a preload is applied to the bearings 56 and 57 via the pinion flange 50 by screwing the nut member 62 into the threaded portion 61 at the end of the pinion shaft 55.

  According to the differential apparatus of the present invention, since the press retainer is configured by press forming a rolled steel plate, phosphorus and sulfur contained in the differential oil do not enter the retainers 19 and 20. For this reason, the cages 19 and 20 of the bearings 56 and 57 do not decrease in strength against the differential oil, have excellent durability, can stably hold the balls 27 and 28, and can smoothly rotate. The pinion shaft 55 is supported in a stable and freely rotatable manner in the differential case 51 over a long period of time. Moreover, since the bearings 56 and 57 are tandem angular ball bearings, the rolling resistance can be reduced, and a high-quality differential device can be provided.

  In rolling, the material is compressed by a roll and the cast structure is destroyed, so that uniform and excellent properties are obtained. For this reason, the cage | basket comprised with a rolled sheet has the advantage that it is more efficient than forging, and its production cost is low. In addition, hot rolling becomes a steel material having a tough structure with a required shape, and cold rolling can achieve thinness, high dimensional accuracy, and mechanical properties that cannot be obtained hot.

  As described above, the embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the number of balls 27 and 28 of the ball groups 15 and 16 and the ball diameter Etc. can be arbitrarily changed. Furthermore, the difference between the pitch circle diameters D1 and D2 of the ball groups 15 and 16 can be variously changed according to the differential device to be used. In the differential device, in the above-described embodiment, the tandem double-row angular contact ball bearings are used for the both bearings 56 and 57. However, either one may be constituted by a tapered roller bearing. The cold rolled plate may be other than SPCC, and the hot rolled plate may be other than SPHC. As the material of the cage, the main point is that even if it is immersed in differential oil, it does not deteriorate in strength due to phosphorus, sulfur, etc. contained in this differential oil, and the rigidity that can hold the ball rotatably. What is necessary is just to have lubricity.

It is an expanded sectional view of the bearing used for the differential apparatus which shows embodiment of this invention. It is sectional drawing of the differential apparatus which shows embodiment of this invention. It is sectional drawing of the conventional tandem type double row angular contact ball bearing. It is sectional drawing of the conventional differential apparatus.

Explanation of symbols

11a, 11b Raceway surface 12 Inner ring 13a, 13b Raceway surface 14 Outer ring 15, 16 Ball group 19, 20 Cage 27, 28 Ball 32 Pocket 51 Differential case 52 Differential reduction mechanism 53 Ring gear 54 Pinion gear 55 Pinion shaft

Claims (3)

A differential case, a differential reduction mechanism disposed in the differential case, a pinion gear that meshes with a ring gear of the differential reduction mechanism, a pinion shaft that supports the pinion gear, and the pinion shaft that is rotatably supported in the differential case A differential device comprising a bearing for
The bearing has an inner ring having a double-row raceway surface, an outer ring having a double-row raceway surface corresponding to the raceway surface of the inner ring, and different pitch circle diameters between the raceway surfaces of each row of the inner ring and the outer ring. A tandem-type double row angular contact ball bearing having a double row ball group to be interposed and a cage for holding the balls of the ball group, and the retainer is formed by press forming a rolled steel plate. A differential device characterized by being a vessel.   The differential apparatus according to claim 1, wherein the rolled steel sheet is a cold rolled sheet.   The differential apparatus according to claim 1, wherein the rolled steel sheet is a hot rolled sheet.

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