JP2007321888A - Differential device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate the setting/adjustment of a differential limiting force by reducing the number of constitution parts related related to the setting of the differential limiting force of a differential device. <P>SOLUTION: A carrier 22 of the differential device constituted in a planetary gear mechanism 2 is made to be an input element, and a sun gear 21 and a ring gear 24 are made to be output elements. A friction engaging device 3 is disposed between the end face 22b of the carrier 22 and the side end 4b of an output gear 4 connected to the sun gear 21, to allow torque engagement between the output elements. The carrier 22 and an input shaft 1 are connected by a helical spline. The output gear 4 is formed as a helical gear, and thrust generated according to a transmitted driving force is applied to the friction engaging device to obtain the differential limiting force. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a differential device for a four-wheel drive vehicle, and more particularly to a differential device that generates a differential limiting force proportional to drive torque.

  The differential device, which is arranged to distribute the power from the engine to the front and rear wheels, is on the slip side against differential rotation when acceleration or one of the front and rear wheels slips. A differential limiting mechanism for limiting differential rotation is provided to transfer the transmitted torque to the other wheel side. A device that operates this differential limiting mechanism in response to a transmission torque is known as a torque-sensitive differential limiting device.

  Such a differential limiting mechanism is applied to a simple planetary gear type differential so that a bias ratio (differential limiting force) can be set large. For example, refer to Patent Document 1, which includes a carrier 101 that is a constituent element of a planetary gear and a housing that accommodates parts by a case 102 that is integrally coupled to the carrier 101, as shown in FIG. A helical gear ring gear 104, a planetary pinion (planet gear) 105, and a sun gear 106 are meshed and accommodated in the housing, and a flange portion 107 of the ring gear 104 is coupled to the coupling 108 and a helical spline 109 is disposed. It is comprised so that it may connect via.

  And the washer 110-116 is interposed between each member, such as the gear which comprises a planetary gear mechanism, the thrust force which generate | occur | produces in each gear is made to act on a corresponding washer, and a frictional force is produced in a washer, and differential limitation is carried out. A differential device that is adapted to obtain force is shown.

JP 2005-16643 A

  In the differential limiting mechanism of the differential device of Patent Document 1, the setting of the bias ratio as the differential limiting force is such that a washer is interposed on each side of a rotating body such as a sun gear, a planetary pinion, and a ring gear that constitutes the differential. The thrust force generated at the time of power transmission of each gear formed on the helical gear and the thrust force generated on the flange engaged with the helical spline are applied to the washer. In order to properly set the bias ratio as the differential limiting force in this differential device, the multiple helical gears and helical splines are set in combination with the torsion angle and a number of washers. There are many adjustment points, which makes it difficult to set the bias ratio. Further, the assembly is complicated due to the configuration in which a large number of washers are interposed.

  The present invention has been made for such a problem. By specifying a member related to the setting of the differential limiting force and minimizing the adjustment portion, the setting / adjustment is facilitated and the assembling property is good. It aims at making it a differential apparatus.

  A differential device according to the present invention includes an input member connected to an input shaft, a planetary pinion rotatably supported by the input member meshed with a sun gear and a ring gear, and an output gear connected to the sun gear to connect the front and rear wheels. In the differential device having the structure in which the ring gear is connected to the connecting member and the output member is connected to the other side of the front and rear wheels, a friction engagement device is disposed between the two output members. The thrust force generating mechanism acting on the friction engagement device is provided on the output member and the input member for the one side.

  The differential apparatus according to the present invention is characterized in that the thrust force generating mechanism is a helical gear of an output member to one side, and is a helical spline provided at a connecting portion of the input member.

  In the differential device according to the present invention, the thrust force generation mechanism generates a thrust force in the same direction when the power transmitted to the input shaft is in the drive transmission state, and a reverse thrust force in the driven state. It is characterized by generating.

  The differential device according to the present invention includes: a sun gear concentrically disposed on an input shaft; an output gear coupled to the sun gear and output to one side of the input shaft; and a carrier coupled to the input shaft. A multi-plate frictional engagement device is interposed between the drive plate and the driven gear on the hub of the output gear, and the multi-plate type by the thrust force generated on the output gear or carrier. A thrust bearing for restricting axial movement is provided at the separated end of the output gear and the carrier, while enabling the friction engagement device to be engaged.

  According to the present invention, only one frictional engagement device is required for the differential limiting force actuating unit, and this frictional engagement device can be operated by only two thrust force generating mechanisms. The number of locations is reduced, and appropriate settings and adjustments are facilitated. Further, since the thrust force is generated by the helical gear and the helical spline, the differential limiting force can be appropriately set by setting the twist angle and the twist direction, and the degree of freedom of setting is increased. In addition, the differential limiting force can be set both when the power transmission is driven and when it is driven, and no special member is required for the arrangement of the friction engagement device. To do.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a skeleton diagram showing a schematic configuration of a differential device of the present invention, and FIG. 2 is a cross-sectional view of the differential device. In FIG. 1, 1 is an input shaft from a transmission (not shown), and a planetary gear mechanism 2 is provided on the input shaft 1. In the planetary gear mechanism 2, a sun gear 21 and a ring gear 24 are concentrically arranged on the input shaft 1, and a planetary pinion 23 rotatably supported by a carrier 22 as an input element meshes with both the gears 21 and 24. The output gear 4 is connected to a sun gear 21 as one output element of the planetary gear mechanism 2, and the driven gear 5 is engaged with the output gear 4 and output to the shaft 6 toward one wheel side. . Further, the ring gear 24 as the other output element outputs the output shaft 8 to the other wheel side via the drum member 7.

  The friction engagement device 3 is disposed between the side portion 4 b of the output gear 4 to one side and the side plate 22 b of the carrier 22, and the friction plates 3 a and 3 b of the friction engagement device 3 are connected to the output gear 4 and the drum member 7. And are engaged with each other. A spline 1 a is provided at the large-diameter end of the input shaft 1, and a boss spline 22 a of the carrier 22 is fitted and connected to the spline 1 a so that input rotation is transmitted to the carrier 22.

  In FIG. 2, the input shaft 1 is a hollow shaft formed with an oil passage 1b, and a spline 1a is provided at the end of the large diameter, and this spline is formed with the spline teeth slanting with respect to the axis. Helical spline 1a. A spline provided on the inner diameter of the boss portion of the carrier 22 is also formed in the helical spline 2a, and the carrier 22 is fitted and connected to the input shaft 1 by both the splines 1a and 2a. With this configuration, a thrust force corresponding to the transmission force can be generated in the spline portion during power transmission. This helical spline can be set with various types of thrust force and thrust direction by setting the twist angle and twist direction.

  The carrier 22 has a side plate 22b fixed to the other side at a predetermined interval, that is, an interval corresponding to the tooth width of the planetary gear, and a plurality of planetary pinions 23 are rotatably supported in the interval portion. ing. Further, a sun gear 21 and a ring gear 24 are meshed with each other on the inner peripheral side and the outer peripheral side of the planetary pinion, and both the sun gear 21 and the ring gear 24 move in the thrust direction in the gap portion of the carrier 22. Is placed in a regulated manner.

  The sun gear 21 is an output member to one side, and a spline 21a is formed on the inner periphery formed in a ring shape so that the spline formed on the outer periphery of the shaft portion 4c of the output gear 4 allows axial movement. Connected to the spline. The output gear 4 configured as described above is rotatably provided on the input shaft 1. The output gear 4 is a drive gear formed on a helical gear, and meshes with a driven gear 5 formed on the helical gear to form a gear train. Thereby, a thrust force can be generated in the output gear 4 during power transmission. This helical gear can also set various thrust forces and thrust directions by setting the twist angle and twist direction.

  A ring gear 24 in which an inner gear is formed on the inner periphery of the large-diameter ring-shaped member has a spline formed on the outer periphery, and is engaged with a spline formed on the inner periphery of the drum member 7. Thereby, the ring gear 24 as the output member to the other side is output to the output shaft 8 to the other side through the drum member 7.

  The frictional engagement device 3 disposed between the carrier 22 and the output gear is a multi-plate type, and a drive plate 3 a that is engaged with a spline formed on the hub portion 4 a of the output gear 4 and a drum member 7. The driven plate 3b is engaged with the formed spline 7a. The friction plates 3a and 3b are engaged with each other by the pressing force between the side end 4b of the output gear 4 and the side plate 22b of the carrier 22. It is supposed to be.

  Further, a thrust bearing 12 is disposed between the inner diameter end 4d of the output gear 4 and a washer 13 provided to the input shaft 1 so as to restrict the axial movement thereof. Further, the carrier 22 restricts movement of the input shaft 1 to the right side of the drawing shaft 11 by a retaining ring 11 via a washer 22d provided on the outer end of the spline 22a, and further, the end of the shaft 8a of the output shaft 8 is supported. A thrust bearing 10 is provided between the two parts to restrict the position.

  For example, when the output side of the differential device configured as described above is connected to one wheel on the front wheel side and the other output shaft 8 is connected to the rear wheel side, it is preferable that the input shaft 1 is driven. In a straight road running on a smooth road surface, no differential rotation occurs between the front wheels and the rear wheels, so that the planetary pinion 23 rotates integrally with the carrier 22 without rotating, and the input rotation is directly transmitted to the front wheels and the rear wheels. . In cornering traveling, differential rotation occurs between the front wheels and the rear wheels. Therefore, a differential function is activated by the planetary pinion 23 revolving while rotating, and the differential rotation is absorbed.

  The helical splines 1a and 22a at the connecting portion of the input shaft 1 and the carrier 22 and the helical gear of the output gear 4 are driven to a magnitude of the driving force when the driving force during forward traveling is input to the input shaft 1. Accordingly, the twist angle and the twist direction are set so that the rightward thrust forces A and B in FIG. 2 are generated. When set in this way, the thrust force A of the output gear 4 acts on the friction engagement device 3 to generate a differential limiting force. In reverse travel (or forward coast), the helical gears and the helical splines generate thrust forces C and D in the opposite direction to the forward travel, and the thrust force D of the carrier 22 is applied to the friction engagement device 3. The differential limiting force can be generated by acting on the.

  Therefore, when the front wheel side slips, the input rotation is transmitted to the front wheel at a speed increased by the differential function of the differential. In this state, a thrust force A is generated according to the driving force transmitted to the output gear 4 and acts on the friction engagement device 3 to generate a differential limiting force, and the transmission torque on the front wheel side is reduced to the rear wheel side. Decrease transfer slip rotation. In the case of this front wheel slip, the driving force output to the output gear is relatively small, so the differential limiting force (torque bias ratio) can be made smaller than in the case of the rear wheel slip described later.

  When slip occurs on the rear wheel side, the input rotation is output so as to increase the speed of the rear wheel by the differential function. In this state, the driving force transmitted to the input shaft 1 is such that the transmission torque to the front wheel side is larger than the transmission torque to the rear wheel side, and a larger thrust force is generated on the output gear 4 than when the front wheel slips. The dynamic limiting force (torque bias ratio) can be increased.

  As described above, in the present invention, the differential limiting force is set by the thrust force generated in the helical gear and the helical spline in one friction engagement device, so that the twist angles of these two thrust force generating portions are set. By setting the size, direction, etc., the differential limiting force (torque bias ratio) can be easily set and adjusted.

  Further, differential limiting can be performed by the thrust force generated in one member during driving, and differential limiting can be performed by the thrust force generated in the other member during driving. Further, since no special member is required for the arrangement of the friction engagement device, the device can be reduced in size and assembled.

It is a skeleton figure of the differential apparatus of an embodiment of the invention. It is sectional drawing of the said differential apparatus. It is sectional drawing of the differential apparatus of a prior art example.

Explanation of symbols

1 Input shaft 2 Planetary gear mechanism 3 Friction engagement device 4 Output gear (helical gear)
7 Drum member (connection member)
8 Output shaft 21 Sun gear 22 Carrier 22a Helical spline 23 Planetary pinion 24 Ring gear

Claims (4)

An input member connected to the input shaft, and a planetary pinion rotatably supported by the input member are meshed with the sun gear and the ring gear, and an output gear is connected to the sun gear to output the output member to one side of the front and rear wheels. In the differential device having a configuration in which the ring gear is connected to a connecting member to be an output member to the other side of the front and rear wheels,
A differential is characterized in that a friction engagement device is disposed between the two output members, and a thrust force generating mechanism acting on the friction engagement device is provided on the output member and the input member to the one side. apparatus.   2. The differential apparatus according to claim 1, wherein the thrust force generating mechanism is a helical gear of an output member to one side and is a helical spline provided at a connecting portion of the input member.   3. The thrust force generating mechanism according to claim 1, wherein the thrust force generating mechanism generates a thrust force in the same direction when the power transmitted to the input shaft is in a drive transmission state, and a reverse thrust force in both cases when the power is transmitted. A differential apparatus characterized by generating   4. The differential gear according to claim 1, wherein the differential device includes a sun gear concentrically disposed on the input shaft, an output gear connected to and integrated with the sun gear and disposed on one side of the input shaft, and the input shaft. A multi-plate friction engagement device is interposed between the carrier connected to the other side, the drive plate is engaged with the hub portion of the output gear, and the driven plate is engaged with the drum member of the output member on the other side. A differential bearing characterized in that the multi-plate frictional engagement device can be engaged by a thrust force generated in a gear or a carrier, and a thrust bearing for restricting axial movement is provided at a separated end portion of the output gear and the carrier. apparatus.

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