Source: http://www.google.com/patents/US5458546?ie=ISO-8859-1
Timestamp: 2015-05-29 09:08:21
Document Index: 642336002

Matched Legal Cases: ['arts 21', 'arts 21', 'arts 21', 'arts 21', 'arts 21', 'arts 21', 'arts 21']

Patent US5458546 - Differential gear assembly - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsDisclosed is a differential gear assembly comprising: a case rotatable around a rotation axis in response to a driving force of an engine; first and second side gears coaxially arranged within the case and supported in such a manner that the first and the second side gears are individually rotatable...http://www.google.com/patents/US5458546?utm_source=gb-gplus-sharePatent US5458546 - Differential gear assemblyAdvanced Patent SearchPublication numberUS5458546 APublication typeGrantApplication numberUS 08/038,923Publication dateOct 17, 1995Filing dateMar 29, 1993Priority dateMar 31, 1992Fee statusPaidAlso published asDE69311612D1, DE69311612T2, EP0563895A1, EP0563895B1, US5562562Publication number038923, 08038923, US 5458546 A, US 5458546A, US-A-5458546, US5458546 A, US5458546AInventorsMasao TeraokaOriginal AssigneeTochigi Fuji Sangyo Kabushiki KaishaExport CitationBiBTeX, EndNote, RefManPatent Citations (14), Referenced by (13), Classifications (7), Legal Events (4) External Links: USPTO, USPTO Assignment, EspacenetDifferential gear assembly
US 5458546 AAbstract
Disclosed is a differential gear assembly comprising: a case rotatable around a rotation axis in response to a driving force of an engine; first and second side gears coaxially arranged within the case and supported in such a manner that the first and the second side gears are individually rotatable around the rotation axis of the case with respect to the case, the first and the second side gears being adapted to be connected to first and second output shafts, respectively; at least one pair of first and second pinion gears each of which has a center axis parallel to the rotation axis of the case, the first pinion gear having first and second gear portions, the second pinion gear having third and fourth gear portions, the first gear portion being engaged with the third gear portion, the second gear portion being engaged with the first side gear, and the fourth gear portion being engaged with the second side gear; and a holding member formed on the case and having a holding bore for holding the first and the third gear portions. The holding bore is brought into contact with entire outer peripheries of the first and the third gear portions in engagement so that the first and the third gear portions with each other can be rotated around each center axis within the holding bore against the friction between the first and the third gear portions and an inner bore surface of the holding bore.
1. A differential gear assembly comprising:a case rotatable around a rotation axis in response to a driving force supplied from a power source; first and second side gears being coaxially supported in said case in such a manner that said first and second side gears are individually rotatable around said rotation axis of the case with respect to said case, said first and second side gears being adapted to be connected to first and second output shafts, respectively; at least one pair of first and second pinion gears, said first pinion gear having first and second gear portions, said second pinion gear having third and fourth gear portions, the first and second pinion gears being arranged in parallel to said rotation axis so that said first gear portion is engaged with said third gear portion, said second gear portion is engaged with said first side gear, and that said fourth gear portion is engaged with said second side gear; and a holding member being provided on said case for holding said first and second pinion gears in such a manner that the first and second pinion gears move with the case around the rotation axis in response to rotation of the case and each of the first and second pinion gears is slidably rotatable around an axis thereof with respect to the holding member, wherein the first and second side gears are adjacent to each other, and the holding member has a bore entirely circumscribing circumferences of said first and third gear portions for preventing axes of the first and second pinion gears from being moved. 2. An assembly as claimed in claim 1, wherein said first and said third gear portions are formed at one ends of said first and said second pinion gears, respectively.
6. An assembly as claimed in claim 5, wherein said case body has a portion covering said first and said second side gears, and said first and said second pinion gears along a circumferential direction, and wherein said cover has a portion covering said first and said second side gears and said first and said second pinion gears along a plane intersecting with said rotation axis of said case.
14. A differential gear assembly comprising:a case rotatable around a rotation axis in response to a driving force supplied from a power source; first and second side gears being coaxially supported in said case in such a manner that said first and second side gears are individually rotatable around said rotation axis of the case with respect to said case, said first and second side gears being adapted to be connected to first and second output shafts, respectively; at least one pair of first and second pinion gears, said first pinion gear having first and second gear portions, said second pinion gear having third and fourth gear portions, the first and second pinion gears being arranged in parallel to said rotation axis so that said first gear portion is engaged with said third gear portion, said second gear portion is engaged with said first side gear, and that said fourth gear portion is engaged with said second side gear; and a holding member being provided on said case for holding said first and second pinion gears in such a manner that the first and second pinion gears move with the case around the rotation axis in response to rotation of the case and each of the first and second pinion gears is slidably rotatable around an axis thereof with respect to the holding member, wherein the first and second side gears are adjacent to each other, and the holding member has a bore entirely circumscribing circumferences of said first and third gear portions for preventing the first and second pinion gears from being moved in the radial direction. Description
Generally, a differential gear assembly used in a vehicle is prepared for occurrence of slipping or skidding of one tire so as to provide a sufficient rotation force to the other tire which is not slipped. For example, such a differential gear assembly is disclosed in Japanese Laid-Open Patent Publication No. (Kokai) 97346/1984.
In order to solve the above-mentioned problems, it is an object of the present invention to provide a differential gear assembly which assures proper support of pinion gears and which can improve the durability and the quietness of the pinion gears.
In order to accomplish the above-mentioned object, a differential gear assembly according to the present invention comprises: a case rotatable around a rotation axis in response to a driving force of an engine; first and second side gears coaxially arranged within said case and supported in such a manner that said first and said second side gears are individually rotatable around said rotation axis of the case with respect to said case, said first and said second side gears being adapted to be connected to first and second output shafts, respectively; at least one pair of first and second pinion gears each of which has a center axis parallel to said rotation axis of said case, said first pinion gear having first and second gear portions, said second pinion gear having third and fourth gear portions, said first gear portion being engaged with said third gear portion, said second gear portion being engaged with said first side gear, and said fourth gear portion being engaged with said second side gear; and a holding member formed on said case and having a holding bore for holding said first and said third gear portions, said holding bore being brought into contact with entire outer peripheries of said first and said third gear portions in engagement so that said first and said third gear portions with each other can be rotated around each center axis within said holding bore against the friction between said first and said third gear portions and an inner bore surface of said holding bore.
In addition, engagement between the first and the second pinion gears is established within the receptacle grooves which are formed at the end of the case and which cover the entire periphery of the gear portions. Accordingly, engagement between the pinion gears can be maintained in an excellent condition and the case can be reduced in size along the rotation axis.
The features and advantages of the differential gear assembly according to the present invention will be more clearly understood from the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings, in which like reference numerals designate the same or similar elements or sections throughout the figures thereof and in which:
FIG. 4 is a view for describing engagement between side gears and pinion gears; FIG. 4(a) shows the gears of the second embodiment shown in FIGS. 5 to 8 and of the third embodiment shown in FIGS. 9 to 15, and FIG. 4(b) shows the gears of the first embodiment shown in FIGS. 1 to 3;
The differential gear assembly comprises a case 1 which includes a cylindrical case body 3 and a cover 5. The case 1 is supported on a body of a vehicle through bearings (not shown). The case 1 is provided with a gear (not shown) attached to the outer periphery of the case 1. The gear is supplied with a rotational force from an engine (not shown) mounted on the vehicle through a power transmission device. Thus, the case 1 is adapted to rotate around a longitudinal rotation axis when driven by the engine.
The chamber 7 of the case 1 accommodates a first side gear 17 and a second side gear 19. The first side gear 17 is fixedly fitted to the first shaft 9 while the second side gear 19 is fixedly fitted to the second shaft 11. The first and the second side gears 17 and 19 are provided at their outer peripheries with helical gear portions 17a and 19a formed in a central area of the case 1. No helical gear portion is provided in peripheral areas around the axial holes.
As illustrated in FIG. 3, the receptacle holes 21 and 23 in each pair are formed in a shape of two small cylinders partially overlapping with each other and with the chamber 7 having a shape of a large cylinder. The inner round walls defining the receptacle holes 21 and 23 surround the outer peripheries of the first and the second pinion gears 29 and 31 engaged with each other. With this structure, an opening 28 is formed in an area where the receptacle holes 21 and 23 communicate with the chamber 7. In this area, engagement between the pinion gears and the side gears is established.
Each of the receptacle holes 21 and 23 are provided at its axial ends with stopper projections 25 and 27 radially projecting from the shaft bearing 6 and the cover 5, respectively. Thus, the first and the second pinion gears 29 and 31 are prevented from axial movement by presence of the stopper projections 25 and 27.
The helical gear portions 33a and 35 of the first pinion gear 29 have outer peripheral surfaces which are brought into contact with the receptacle hole 21 to cause friction against the inner wall surface of the receptacle hole 21. Accordingly, when the first pinion gear 29 is subjected to the rotational force which is greater than a predetermined frictional force, the first pinion gear 29 is allowed to rotate around the center axis within the receptacle hole 21. The second pinion gear 31 and the receptacle hole 23 are arranged in the manner similar to the first pinion gear 29 and the receptacle hole 21.
In this embodiment, the support portions 41 and 43 are integrally formed with the walls defining the receptacle hole parts 21a and 23a for receiving the first and the third gear portions 33a and 37a and with the walls defining the receptacle hole parts 21b and 23b for receiving the first and the third gear portions 33b and 37b, respectively. Specifically, at the side of the first shaft 9, two overlapping cylindrical bores for holding the first and second gear portions 33a and 37a are formed, as the receptacle hole parts 21a and 23a, in the side wall region which connects the outer periphery of the case 3 and the shaft bearing 6. Likewise, at the side of the second shaft 11, two overlapping cylindrical bores are formed, as the receptacle hole parts 21b and 23b, in the region projecting from the cover 5 in parallel to the rotation axis.
The support portions 41 and 43 of the above-mentioned structure have support surfaces each of which forms a part of the round outline of the two overlapping cylinders. The support surfaces close the opening 28 at the receptacle hole parts 21a, 21b, 23a, and 23b which receive the gear portions 33a, 33b, 37a, and 37b. Thus, the outer periphery of the first and the third gear portions of the first and the second pinion gears 29 and 31 in engagement is completely surrounded by the support surfaces and the inner wall surfaces of of the receptacle holes 21 and 23. In this event, the support portions 41 and 43 support the first gear portions 33a and 33b of the first pinion gear 29 and the third gear portions 37a and 37b of the second pinion gear 31 radially outwardly from the center side of the case 1. Thus, radial displacement of the center axes of the pinion gears is restricted. Accordingly, the pinion gears are held by the inner walls of the receptacle holes and the support portions so that the center axes are properly positioned.
More specifically, the case body 3 and the cover 5 are provided with four pairs of the receptacle holes 21 and 23 formed along the periphery of the chamber 7. Axially outwardly of the receptacle holes 21 and 23, the stopper projections 25 and 27 project along a radial direction of the case 1. In the receptacle holes 21 and 23, the walls defining the receptacle hole parts 21b and 23b and formed on the cover 5 are continuous to the support portion 43 and have the inner peripheral surfaces covering the entire periphery of the first and the third gear portions 33b and 37b of the pinion gear. The receptacle hole parts 21c and 23c formed on the case body 3 are provided with an opening 28 communicating with the chamber 7.
A first pinion gear 30 is provided at its end faced to the cover 5 with the first helical gear portion 33b. Likewise, the second helical gear portion 35 is formed at the end faced to the case body 3. The first and the second gear portions 33b and 35 are connected through an extension boss 45.
On the other hand, a second pinion gear 32 is provided with the third and the fourth helical gear portions 37b and 39 throughout the entire periphery. Since the third gear portion 37a and the boss for connection thereof are omitted, the entire length of the second pinion gear 32 is shorter than the first pinion gear 30 by the axial length of the gear portion 18a of the first side gear 18.
In the second embodiment, the first and the second pinion gears 30 and 32 can be further reduced in length by omission of the first and the third helical gear portions 33a and 37a. Thus, this embodiment is particularly adapted to reduce the size and the weight of the differential gear assembly.
Referring to FIGS. 9, 10, and 11, a case 47 comprises a case body 49 and a cover 51. The first and the second shafts 9 and 11 are rotatably inserted into a chamber 53 in the case 47 through the first and the second axial holes 13 and 15, respectively. The first and the second side gears 18 and 20 are fitted on the peripheries of the first and the second shafts 9 and 11. The case body 49 is provided with four pairs of receptacle holes 55 and 57 symmetrically arranged at four positions along the outer periphery of the chamber 53. The receptacle holes 55 and 57 are provided with an opening 59 formed at the side of the rotation axis and opened towards the chamber 53.
Although the helical gear is used as the gear portion in the foregoing embodiment, use may be made of a spur gear. It is noted that the helical gear provides a great differential limiting force by the use of a gear thrust force. By adjusting the orientation of the gear teeth, the differential limiting force during the straightforward movement drive can be made greater than that during the straightforward movement with an engine brake operated. It is therefore possible to reduce the interference with ABS (Anti-block Breaking System). Thus, the helical gear is preferable.
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