JP2011141011A - Differential gear for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a differential gear for a vehicle attaining miniaturization and cost reduction of a clutch. <P>SOLUTION: The differential gear for the vehicle includes a differential mechanism 2 having a sun gear 2C and an internal gear 2D set to a torque distribution ratio making each distribution torque mutually different and distributing the driving torque of a drive source to the sun gear 2C and the internal gear 2D, and a pressing mechanism 4 generating a pressing force serving as a differential limiting force to the differential mechanism 2 and adjusting the pressing force according to the direction of differential rotation of the sun gear 2C and internal gear 2D. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vehicle differential device, and more particularly to a vehicle differential device provided with a clutch for limiting the differential of a differential mechanism.

  As a conventional vehicle differential device, there is one in which a pair of output shafts are connected by a clutch to limit differential of a differential mechanism (Patent Document 1).

  The vehicle differential device includes a housing as an input member that rotates together with an input shaft, a differential mechanism that differentially distributes the rotational force from the housing, a clutch that limits the differential of the differential mechanism, And a drive mechanism for driving the clutch.

  The housing includes a bottomed cylindrical front housing that opens to one side, and an annular rear housing that is attached to the opening of the front housing, and is connected to the input shaft. The housing is configured to rotate by receiving a driving force of a driving source such as a vehicle engine from an input shaft.

  The differential mechanism includes an internal gear and a sun gear as a pair of output gears respectively connecting a pair of output shafts, and a planetary gear as an input gear meshing with the internal gear and the sun gear, and is accommodated in a housing. ing. The pair of output shafts is set to a torque distribution ratio (a: b) that makes the distribution torques (a, b) different from each other. One output shaft of the pair of output shafts is connected to an internal gear having a distributed torque a, and the other output shaft is connected to a sun gear having a distributed torque b (a> b). The differential mechanism is configured to differentially distribute the rotational force from the housing to the pair of output shafts.

  The clutch includes an outer clutch plate and an inner clutch plate, and is configured as a main clutch disposed between the inner peripheral surface of the internal gear and the outer peripheral surface of the sun gear. The clutch is configured such that the outer clutch plate and the inner clutch plate are frictionally engaged to connect the pair of output shafts to limit the differential of the differential mechanism. The outer clutch plate is splined to the inner peripheral surface of the internal gear, and the inner clutch plate is splined to the outer peripheral surface of the sun gear.

  The drive mechanism has an electromagnetic clutch, a pilot clutch that is driven by receiving the electromagnetic force of the electromagnetic clutch, and a cam that converts the rotational force from the housing into a pressing force toward the main clutch by driving the pilot clutch. , Arranged around the pair of output shafts and housed in the housing. The drive mechanism is configured to frictionally engage the outer clutch plate and the inner clutch plate by applying a pressing force from the output member of the cam to the main clutch side.

  With the above configuration, for example, when a driving force from the engine side of the vehicle is input to the housing via the input shaft, the housing rotates around the rotation axis. When the housing rotates, this rotational force is transmitted to the planetary gear, and further transmitted from the planetary gear to the internal gear and the sun gear. Since the output shaft is connected to each of the internal gear and the sun gear, the driving force from the engine side is differentially distributed according to the running condition of the vehicle, and the differentially distributed torque is transmitted to the left and right output shafts. Is done.

  In this case, when the electromagnetic clutch is energized, the pilot clutch is driven by the electromagnetic force of the electromagnetic clutch. Next, when the cam receives a rotational force from the housing when the pilot clutch is driven, the rotational force is converted into a pressing force by the cam, and this pressing force is applied to the main clutch. Then, the outer clutch plate and the inner clutch plate of the main clutch are relatively close to each other and frictionally engaged, and by this frictional engagement, the sun gear and the internal gear, that is, a pair of sun gears and internal gears respectively corresponding to the sun gear and the internal gear. The output shafts are connected to each other so as to transmit the rotational force of the housing. Thereby, the differential of the differential mechanism is limited.

Japanese Patent No. 3847359

  However, according to the vehicle differential device of Patent Document 1, the clutch according to the torque capacity required when the output shaft on the internal gear side of the pair of output shafts rotates faster than the output shaft on the sun gear side. Capacity was determined. This is because if the capacity of the clutch is determined according to the torque capacity required when the output shaft on the sun gear side rotates faster than the output shaft on the internal gear side, the output shaft on the internal gear side This is because the required torque capacity cannot be obtained when rotating faster than the output shaft. As a result, in order to obtain a desired clutch capacity, the number of clutch plates of the clutch is increased, and there is a problem that the clutch is not only enlarged in the axial direction but also increased in cost.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a vehicle differential device capable of reducing the size and cost of a clutch.

  In order to achieve the above object, the present invention has a pair of output members set to a torque distribution ratio in which each distribution torque is different from each other, and a difference in which the drive torque of the drive source is distributed to the pair of output members. A difference for a vehicle comprising: a moving mechanism; and a pressing mechanism that generates a pressing force as a differential limiting force for the differential mechanism and varies the pressing force according to a differential rotation direction of the pair of output members. Provide a moving device.

  According to this structure, the differential limiting force with respect to a differential mechanism generate | occur | produces with the different pressing force according to the direction of differential rotation of a pair of output member.

  The pressing mechanism includes a first cam that rotates by receiving a rotational force transmitted from one output member of the pair of output members via the clutch, and the first cam that faces the first cam. The cam mechanism may include a cam and a second cam that can rotate relative to each other, and the first cam and the second cam may each have two types of cam surfaces that have different gradients.

  According to this configuration, the pressing force is variable according to the gradient of the cam surface that generates the pressing force among the two types of slow and rapid cam surfaces.

  Further, the pressing mechanism includes a pressing member that rotates by receiving a rotational force transmitted from one output member of the pair of output members via the clutch, and the pressing member is a member of the pair of output members. It is good to comprise so that it may be connected with the other output member by helical spline fitting.

  According to this configuration, the pressing force is variable by setting the twist direction of the helical spline corresponding to the differential rotation direction of the pair of output members.

  Further, the pressing mechanism includes a pressing member that rotates by receiving a rotational force transmitted from one output member of the pair of output members via the clutch, and the pressing member is a member of the pair of output members. The other output member is connected to the other output member by cam coupling, and the pressing member has two kinds of slow and steep cam surfaces that are parallel to each other in the rotational direction and have different gradients, and the other output member is It is good to comprise so that it may have 2 types of slow and steep cam surfaces which oppose the said 2 types of slow and rapid cam surfaces, and each gradient differs mutually.

  According to this configuration, the pressing force is variable according to the gradient of the cam surface that generates the pressing force among the two types of slow and rapid cam surfaces.

  According to the present invention, it is possible to reduce the size and cost of the clutch.

Sectional drawing shown in order to demonstrate the whole vehicle differential device which concerns on the 1st Embodiment of this invention. The disassembled perspective view shown in order to demonstrate the internal element of the differential for vehicles which concerns on the 1st Embodiment of this invention. (A) And (b) is sectional drawing shown roughly in order to demonstrate the cam surface of the differential for vehicles which concerns on the 1st Embodiment of this invention. (A) shows a steep cam surface, and (b) shows a state where a thrust force is generated on a gentle cam surface. Sectional drawing shown in order to demonstrate the whole vehicle differential device which concerns on the 2nd Embodiment of this invention. The disassembled perspective view shown in order to demonstrate the press mechanism of the differential for vehicles which concerns on the 2nd Embodiment of this invention. The disassembled perspective view shown in order to demonstrate the press mechanism of the differential for vehicles which concerns on the 3rd Embodiment of this invention. (A) And (b) is sectional drawing shown roughly in order to demonstrate the cam surface of the differential for vehicles which concerns on the 3rd Embodiment of this invention. (A) shows a steep cam surface, and (b) shows a state where a thrust force is generated on a gentle cam surface.

[First embodiment]
(Overall configuration of vehicle differential)
FIG. 1 shows the entire vehicle differential. FIG. 2 shows the internal elements of the vehicle differential. In FIG. 1, a vehicle differential device denoted by reference numeral 1 is used as a center differential that distributes the driving force of a drive source of a four-wheel drive vehicle, for example, to a differential device on the front wheel side and a differential device on the rear wheel side. A differential mechanism 2 that differentially distributes the drive torque (engine torque) of the source to a pair of output shafts (not shown) on the front wheel side and the rear wheel side, and a function of limiting the differential of the differential mechanism 2 The differential limiting mechanism 3 and a pressing mechanism 4 that generates a pressing force as a differential limiting force by the differential limiting mechanism 3 are roughly configured.

(Configuration of differential mechanism 2)
As shown in FIGS. 1 and 2, the differential mechanism 2 includes a planetary carrier 2A as an input member, a plurality of planetary gears 2B, 2B,... That receive the rotational force of the planetary carrier 2A, and the plurality of planetary gears. 2B, 2B,... As an output member, and an internal gear 2D as an output member meshing with a plurality of planetary gears 2B, 2B,... On the same axis as the sun gear 2C, A gear 2D, a sun gear 2C, a planetary carrier 2A, and a plurality of planetary gears 2B, 2B,...

  The planetary carrier 2A is composed of a carrier base portion 20A and a carrier collar portion 21A, and is disposed between the sun gear 2C and the internal gear 2D. The planetary carrier 2A is formed by a stepped cylindrical body having different inner diameters and outer diameters. Has been. The planetary carrier 2A is configured to be able to rotate around the rotation axis O. The planetary carrier 2A is provided with a gear housing support portion 22A for housing and supporting the planetary gears 2B, 2B,.

  The gear housing support portion 22A includes a first housing hole 220A and a second housing hole 221A, and is disposed across the carrier base portion 20A and the carrier flange portion 21A.

  The first accommodation hole 220A opens in the radial inner side of the planetary carrier 2A (inner peripheral surface of the carrier flange 21A) and in the direction parallel to the rotation axis O (sun gear side and internal gear side). Has been placed. The inner peripheral surface (torque transmission surface) of the first accommodation hole 220A is a first gear support surface made of a curvature surface that fits the tooth tip surfaces of the gear portions 20B, 20B,... (Described later) of the planetary gears 2B, 2B,. 2200A.

  The second accommodation hole 221A opens in the radial direction outside of the planetary carrier 2A (the outer peripheral surface of the carrier base 20A) and the direction parallel to the rotation axis O (sun gear side), and communicates with the first accommodation hole 220A. It is disposed on the base 20A. The inner peripheral surface (torque transmission surface) of the second accommodation hole 221A is a second gear support surface made of a curvature surface adapted to the tooth tip surfaces of the gear portions 21B, 21B,... (Described later) of the planetary gears 2B, 2B,. 2210A. The bottom surface of the second accommodation hole 221A is a third gear support surface as a carrier side support surface that slidably supports the axial end surfaces (free end surfaces) of the gear portions 21B, 21B,... Of the planetary gears 2B, 2B,. A surface 2211A is formed.

  The carrier base 20A is formed by a cylindrical body that opens in the direction of the rotational axis of the planetary carrier 2A. 200 A of straight spline fitting parts which connect an input shaft (not shown) so that a movement is possible are provided in the internal peripheral surface of 20 A of carrier base parts.

  The carrier collar portion 21A is provided continuously with the carrier base portion 20A, and is formed by an annular body that opens in the rotation axis direction of the planetary carrier 2A. The outer diameter of the carrier collar 21A is set to be larger than the outer diameter of the carrier base 20A, and the inner diameter thereof is larger than the inner diameter of the carrier base 20A.

The planetary gears 2B, 2B,... Have different pitch circle diameters D ₁ and D ₂ (D ₁ > D ₂ ) from each other (the torsion directions are the same). the gear specifications pitch circle diameter D _1, the gear portion 21B is a helical gear having with) the gear specifications pitch circle diameter D _2, in the first housing hole 220A and the second housing hole 221A of the planetary carrier 2A It is housed so that it can rotate.

The gear portion 20B meshes with the sun gear 2C and is housed in the first housing hole 220A so as to be capable of rotating. And the gear part 20B is comprised so that the rotational force of the planetary carrier 2A can be transmitted via the sun gear 2C to the output shaft (front wheel side output shaft) which can be arrange | positioned at the left side of FIG. An annular thrust washer 5 located on the outer periphery of the sun gear 2C is provided between the axial front end surface (free end surface) of the gear portion 20B and the bottom surface (fourth gear support surface 210C) of the flange portion 21C of the sun gear 2C. Is intervening. Number of teeth _{Z 1} of the gear portion 20B is set to the tooth number larger than the number of teeth _Z 2 of the gear portion 21B _(Z 1> _{Z 2).} In the present embodiment, Z ₁ = 8 and Z ₂ = 5 are set.

  The gear portion 21B meshes with the internal gear 2D and is housed in the second housing hole 221A so as to be capable of rotating. And the gear part 21B is comprised so that the rotational force of the planetary carrier 2A can be transmitted via the internal gear 2D to the output shaft (rear wheel side output shaft) which can be arrange | positioned at the right side of FIG.

The sun gear 2C meshes with the gear portions 20B, 20B,... Of the planetary gears 2B, 2B,..., Is rotatably arranged on the axis of the internal gear 2D, and is housed in the planetary carrier 2A. It is formed by a cylindrical helical gear having the same axis as O. The sun gear 2C receives the rotational force from the gear portions 20B, 20B,... Of the planetary gears 2B, 2B,... And outputs it to an output shaft (front wheel side output shaft) that can be arranged on the left side of FIG. It is configured. A straight spline fitting portion 20C for movably connecting the output shaft is provided on the inner peripheral surface of the sun gear 2C. Pitch circle diameter _{D 3} and the number of teeth _{Z 3} of the sun gear 2C is the planetary gears 2B, 2B, ... of the gear portions 20B, 20B, ... large dimensions and number of teeth than the pitch circle diameter _{D 1} and the number of teeth _{Z 1} in the Is set. On the outer peripheral surface of the sun gear 2 </ b> C, a flange portion 21 </ b> C is provided that is located at the end opposite to the planetary carrier side end.

  The collar portion 21C is provided with a fourth gear support surface 210C as a gear-side support surface that slidably supports the axial end surfaces of the planetary gears 2B, 2B,... (Gear portions 20B, 20B,...). Yes.

  The internal gear 2D is composed of a boss portion 20D and a gear portion 21D. The internal gear 2D meshes with the gear portions 21B, 21B,... Of the planetary gears 2B, 2B,. It is formed by a cylindrical helical gear having the same axis as the axis O. The internal gear 2D receives the rotational force from the gear portions 21B, 21B,... Of the planetary gears 2B, 2B,... And outputs it to the output shaft (rear wheel side output shaft) that can be arranged on the right side of FIG. It is configured.

  The boss portion 20D is entirely made of a cylindrical body, and is disposed at a position facing the end surface in the axial direction of the sun gear 2C via the planetary carrier 2A. A spline fitting portion 200D for movably connecting the rear wheel side output shaft is provided on the inner peripheral surface of the boss portion 20D. On one side in the axial direction of the boss portion 20D on the planetary carrier side, a flange portion 201D is provided as a second cam having an end surface facing the end surface on the opposite side of the sun gear side end surface of the planetary carrier 2A.

  The flange portion 201D is provided with a straight spline fitting portion 2010D that is located on the outer peripheral surface thereof and extends around the axis of the internal gear 2D. Further, the flange portion 201D is provided with a plurality of cam holes 2011D (shown in FIG. 3) that open to an end surface opposite to the planetary carrier side end surface and are arranged in parallel at a predetermined interval in the circumferential direction.

  Each cam hole 2011 </ b> D is formed by a concave hole extending from the bottom surface side toward the opening side. Each cam hole 2011D is provided with cam surfaces 2012D and 2013D (shown in FIG. 3) for rolling the cam follower 4B.

  The cam surfaces 2012D and 2013D are formed of two types of inclined surfaces that are parallel to each other in the rotation direction of the flange portion 201D and have different gradients. Here, the cam surface 2012D is a gentle slope, and the cam surface 2013D is a steep slope.

  The gear portion 21D extends inward from a cylindrical portion in which a helical gear meshing with the gear portions 21B, 21B,... Of the planetary gears 2B, 2B,. And a bottom part having a through hole formed in the center part, and the whole is formed of a bottomed cylindrical body. An axial straight spline fitting portion 2100D is formed on the inner peripheral surface of the bottom portion of the gear portion 21D over a length corresponding to the thickness of the bottom portion.

  The spline fitting portion 2100D is fitted to the straight spline fitting portion 2010D of the boss portion 20D. This fitting is not done by press fitting. Between the spline teeth of the spline fitting portion 2100D of the gear portion 21D and the spline teeth of the spline fitting portion 2010D of the boss portion 20D, the gear portion 21D and the gear portion 21D are pressed by the pressing force generated in the pressing mechanism 4 described later. A slight circumferential gap is formed so that the boss 20D can move relative to the boss 20D. Thus, the gear portion 21D and the boss portion 20D are connected so as to be relatively movable in the axial direction and to rotate integrally.

Pitch circle diameter D ₄ of the gear portion 21D are set to larger than the pitch circle diameter D ₃ of the sun gear 2C. Thereby, the pitch diameter of the input side gear (the gear portions 20B, 20B,... And the gear portions 21B, 21B,... Of the planetary gears 2B, 2B,...) And the pitch of the output side gears (sun gear 2C and internal gear 2D). D ₃ / D ₁ <D ₄ / D ₂ is established with respect to the circle diameter, and rotation transmitted from the engine side to the internal gear 2D via the gear portions 21B, 21B,... Of the planetary gears 2B, 2B,. The torque becomes larger than the rotational torque transmitted to the sun gear 2C via the gear portions 21B, 21B,... Of the planetary gears 2B, 2B,. The number of teeth Z of the gear portion 21D ₄ is set to the tooth number larger than the number of teeth Z ₃ of the sun gear 2C.

  On the outer peripheral surface of the gear portion 21D, a flange portion 210D is provided as a thrust force receiving portion on one side which is located at the end portion opposite to the boss portion side end portion and faces the flange portion 21C of the sun gear 2C. ing. A plurality of concave holes 211D, 211D,... Opened at an end surface opposite to the planetary carrier side end surface and arranged in parallel at a predetermined interval in the circumferential direction are provided at the bottom of the gear portion 21D. In the concave holes 211D, 211D,..., A sphere 6 made of a non-magnetic material such as stainless steel is mounted with a part thereof exposed, thereby restricting the axial movement of the armature 31A (described later). Yes.

  The differential case 2E is a substantially circular ring-shaped front case 20E that opens in one direction along the rotation axis O, and an opening on the right side of the front case 20E in FIG. 1 (a component insertion port 2010E described later). The rear case 21E of the front case 20E is welded to the planetary carrier side end surface of both end surfaces in the axial direction of the flange portion 21C of the sun gear 2C. The entire differential case 2E is formed of a stepped hollow structure that accommodates the differential mechanism 2 and the differential limiting mechanism 3 therein.

  The front case 20E is formed of a stepless bottomless cylindrical body composed of two large and small cylindrical portions 200E and 201E having different inner diameters and outer diameters.

  One (large diameter) cylindrical portion 200E has an inner circumferential surface of a step portion 2000E as a thrust force receiving portion on the other side facing the flange portion 210D of the internal gear 2D (gear portion 21D) via the thrust washers 7 and 8. And disposed on one side in the axial direction of the front case 20E. Then, the step portion 2000E is configured to receive a thrust force generated in the gear portion 21D of the internal gear 2D by meshing between the planetary gears 2B, 2B,... (Gear portions 21B, 21B) and the internal gear 2D.

  The other (small diameter) cylindrical portion 201E has a component insertion port 2010E on the rear case side, and is disposed on the other side in the axial direction of the front case 20E. A straight spline fitting portion 2011E is provided on the inner peripheral surface of the cylindrical portion 201E. The straight spline fitting portion 2011E is located at a portion close to the cylindrical portion 200E.

  The rear case 21E includes first to third case elements 210E to 212E, and is screwed into the component insertion port 2010E of the front case 20E (cylindrical portion 201E) to be prevented from rotating.

  The first case element 210E has a flange portion 2100E facing the flange portion 201D of the internal gear 2D (boss portion 20D) on the outer peripheral surface, and is entirely formed of a cylindrical body made of a magnetic material such as soft iron. A needle bearing 9 is interposed between the inner peripheral surface of the first case element 210E and the outer peripheral surface of the internal gear 2D (boss portion 20D).

  The second case element 211E has a flange portion 2110E facing the flange portion 201D of the internal gear 2D (boss portion 20D) on the inner peripheral surface, and is entirely formed of a cylindrical body made of a magnetic material such as soft iron. An annular space C is formed between the inner peripheral surface of the second case element 211E and the outer peripheral surface of the first case element 210E.

  The third case element 212E is interposed between the flange portion 2100E of the first case element 210E and the flange portion 2110E of the second case element 211E, and is a circle for connecting the case element, which is entirely made of a nonmagnetic material such as stainless steel. It is formed by a ring.

(Configuration of differential limiting mechanism 3)
As shown in FIG. 1, the differential limiting mechanism 3 includes an electromagnetic clutch 3A as an output drive source and a pilot clutch 3B that functions by driving the electromagnetic clutch 3A, and includes a front case 20E (a small-diameter cylindrical portion). 201E) and the outer peripheral surface of the internal gear 2D (boss portion 20D).

  The electromagnetic clutch 3A includes an electromagnetic coil 30A and an armature 31A, and is disposed on the outer periphery of the boss portion 20D of the internal gear 2D. The electromagnetic coil 30A is disposed in the annular space C of the rear case 21E, and is supported on the outer peripheral surface of the first case element 210E via a bearing (ball bearing) 10 so as to be relatively rotatable. The armature 31A is disposed on the left axle side of the pilot clutch 3B, and is connected to the straight spline fitting portion 2011E of the front case 20E (small diameter cylindrical portion 201E) so as to be movable in the gear axis direction (rotation axis O direction). ing. And it is comprised so that it may move to the direction approaching the inner end surface of the rear case 21E with the electromagnetic force of 30 A of electromagnetic coils.

  The pilot clutch 3B is a friction clutch having a plurality of inner clutch plates 30B, 30B,... And a plurality of outer clutch plates 31B, 31B,... And is disposed between the armature 31A and the rear case 21E. Then, the differential case 2E and the pressing mechanism 4 (cam 4A described later) are connected so as to be intermittent, and the rotational force of the differential case 2E (sun gear 2C) can be transmitted to the cam 4A.

  The inner clutch plates 30B, 30B,... And the outer clutch plates 31B, 31B,... Are alternately arranged along the rotation axis O at positions facing each other, and are entirely formed by an annular friction plate. The inner clutch plates 30B, 30B, ... are on the outer peripheral surface of the cam member 30C, and the outer clutch plates 31B, 31B, ... are on the inner peripheral surface (straight spline fitting portion 2011E) of the front case 20E (small diameter cylindrical portion 201E). Each is fitted with a spline.

(Configuration of the pressing mechanism 4)
3A and 3B show a pressing mechanism. As shown in FIGS. 3 (a) and 3 (b), the pressing mechanism 4 is a flange 201D as the second cam of the aforementioned internal gear 2D and a first cam that rotates by receiving the rotational force from the differential case 2E. 4A and a cam mechanism 4B that generates a pressing force by relative rotation between the cam 4A and the flange portion 201D of the internal gear 2D. A planetary carrier 2A and a rear case 21E (both shown in FIG. 1) And is connected to the differential case 2E (front case 20E) via a pilot clutch 3B (both shown in FIG. 1) in an intermittent manner. Then, the pressing mechanism 4 generates pressing forces Ta and Tb (Ta <Tb) as differential limiting forces for the differential mechanism 2 together with the cam surfaces 2012D and 2013D of the flange portion 201D, and this pressing force is used as the sun gear 2C. And it is comprised so that it may vary according to the direction of differential rotation of internal gear 2D.

  The cam 4A is disposed on the outer periphery of the internal gear 2D (boss portion 20D), and is rotatably supported on the inner end surface of the first element 210E via a bearing (needle bearing) 11. The cam 4 </ b> A is provided with a plurality of cam holes 40 </ b> A that open to the planetary carrier side end surface and are arranged in parallel at a predetermined interval in the circumferential direction.

  Each cam hole 40A is formed by a concave hole that widens from the bottom surface side toward the opening side. Each cam hole 40A is provided with cam surfaces 400A and 401A for rolling the cam follower 4B.

The cam surfaces 400A and 401A are formed of two types of inclined surfaces that are adjacent to each other in the rotational direction of the cam 4A and have different gradients. Here, the cam surface 400A is a gentle slope, and the cam surface 401A is a steep slope. As a result, when the sun gear 2C (shown in FIG. 1) rotates faster than the internal gear 2D (shown in FIG. 1), the cam follower 4B is moved from the cam surface 401A as shown in FIG. 3 (a). pressing force Ta of the cam surface 2013D is generated, the thrust force Ta ₁ in the internal gear 2D is applied via. When the internal gear 2D rotates faster than the sun gear 2C, a pressing force Tb is generated from the cam surface 400A to the cam surface 2012D via the cam follower 4B, and a thrust force Tb ₁ (Tb ₁₎ is generated on the internal gear 2D. ₁ > Ta ₁ ).

  The cam follower 4B is interposed between the cam surfaces 400A and 401A of the cam hole 40A in the cam 4A and the cam surfaces 2012D and 2013D of the cam hole 2011D in the internal gear 2D (the flange portion 201D), and is entirely formed by a sphere (ball). Is formed. The cam follower 4B is configured to apply a pressing force in the gear axis direction generated by the rotation of the cam 4A to the boss portion 20D of the internal gear 2D.

[Operation of the differential 1 for a vehicle]
When torque from the engine side of the vehicle is input to the planetary carrier 2A, the planetary carrier 2A is rotationally driven around the rotation axis O. When the planetary carrier 2A is rotationally driven, this rotational force is transmitted to the planetary gears 2B, 2B,..., And from the gear portions 20B, 20B,. Are transmitted to the internal gear 2D from the gear portions 21B, 21B,. In this case, the sun gear 2C is spline-fitted to the front wheel side output shaft and the inner gear 2D is spline fitted to the rear wheel side output shaft, respectively, so that torque from the engine side is transmitted to the planetary carrier 2A and the planetary gears 2B, 2B,. Further, it is transmitted to the output wheels on the front wheel side and the rear wheel side via the sun gear 2C and the internal gear 2D.

Here, when the vehicle is in a straight traveling state and no slip occurs between the left and right wheels with the road surface, when torque from the engine side is transmitted to the planetary carrier 2A, the planetary carrier 2A is rotated about the rotation axis O. , And the planetary gears 2B, 2B,... Revolve around the center axis of the sun gear 2C and the internal gear 2D without rotation, and the planetary gears 2B, 2B,. Since it rotates together with the planetary carrier 2A, the torque from the engine side is on the road surface within the differential limit torque distribution at the time of static friction based on the torque distribution ratio of D ₃ / D ₁ : D ₄ / D _{2 on} each output shaft. Immediately responding to reaction force imbalance, it is transmitted to the left and right output shafts without loss, and the left and right output shafts rotate at the same rotational speed.

  On the other hand, for example, when slip occurs between the rear wheel and the road surface, the planetary gears 2B, 2B,... Rotate while meshing with the sun gear 2C and the internal gear 2D. It rotates at a speed lower than the rotational speed of the planetary carrier 2A, the output shaft on the rear side rotates at a speed higher than the rotational speed of the planetary carrier 2A, and the torque from the engine side is distributed unevenly between the left and right output shafts. By distributing a larger torque to the front axle with a large road reaction force, the left and right total driving force loss can be reduced and the torque transmission to the rear wheel causing the slip can be reduced. Then, the state of the slip is eased.

  In the present embodiment, differential limiting torque is generated in the output side gear (sun gear 2C and internal gear 2D) by the following action in a state where the engine torque is input to the planetary carrier 2A.

  When the planetary gears 2B, 2B,... Rotate, the tooth tips of the planetary gears 2B, 2B,... (Gear portions 20B, 20B,... And the gear portions 21B, 21B,...) Are planetary carriers 2A (first accommodation holes). 220A and the second receiving hole 221A) of the first gear support surface 2200A and the second gear support surface 2210A, and the planetary gears 2B, 2B,... (The gear portions 21B, 21B,. Since each slides on the third gear support surface 2211A of the (second housing hole 221A), the first gear support surface 2200A, the second gear support surface 2210A and the tooth tip surfaces of the planetary gears 2B, 2B,. Friction resistance is generated between the front end surface of the planetary gears 2B, 2B,... And the third gear support surface 2210A, and differential restriction is imposed on the sun gear 2C and the internal gear 2D by the friction resistance. Torque is generated.

  On the other hand, by the rotation of the planetary gears 2B, 2B,..., A thrust force is generated along the rotation axis O in each gear (the planetary gears 2B, 2B,. In this case, the planetary gears 2B, 2B,... Move in the direction approaching the flange 21C of the sun gear 2C, and the sun gear 2D and the internal gear 2D move to the differential limiting mechanism 3 side.

  At this time, the axial end surfaces of the gear portions 20B, 20B,... Of the planetary gears 2B, 2B,... Are in pressure contact with the flange portion 21C (fourth gear support surface 210C) of the sun gear 2C via the thrust washer 5. Friction resistance is generated through the thrust washer 5 between the fourth gear support surface 210C of the flange 21C and the axial end surfaces of the planetary gears 2B, 2B,..., And the sun gear 2C and the internal gear are also generated by these friction resistances. Differential limiting torque is generated in 2D.

  Further, since the flange portion 210D of the internal gear 2D (gear portion 21D) is pressed against the step portion 2000E of the differential case 2E (front case 20E) via the thrust washers 7 and 8, the step portion 2000E of the differential case 2E and the internal gear 2D Friction resistance is generated between the flange 210D and the thrust washers 7 and 8, and differential limiting torque is generated between the sun gear 2C and the internal gear 2D due to the friction resistance.

  Here, when the electromagnet 30A of the differential limiting mechanism 3 (electromagnetic clutch 3A) is energized, a magnetic circuit is formed across the front case 20E, the rear case 21E, and the armature 31A, and the armature 31A is electromagnet side (rear case side) by the magnetic force. Move to. The movement of the armature 31A causes the pilot clutch 3B (the inner clutch plates 30B, 30B,... And the outer clutch plates 31B, 31B,...) To be pressed toward the rear case, and the inner clutch plates 30B, 30B,. 31B, 31B, ... are relatively close to each other and frictionally engage with each other.

For this reason, the cylindrical portion 201E of the differential case 2E (front case 20E) and the cam 4A of the pressing mechanism 4 are coupled so as to be able to transmit torque, and the rotational force of the differential case 2E (sun gear 2C) is transmitted to the pressing mechanism 4. By transmitting this rotational force to the pressing mechanism 4, the rotational force of the sun gear 2C is converted into pressing forces Ta ₁ and Tb ₁ in the gear axis direction, and this pressing force is converted to the internal gear 2D (boss portion 20D) and the planetary carrier 2A ( It is transmitted to the sun gear 2C via the carrier base 20A).

Thus, the planetary gears 2B, 2B,... (Gear portions 20B, 20B,...) And the sun gear 2C are engaged, and the planetary gears 2B, 2B,... (Gear portions 21B, 21B,. Thus, the thrust force generated by the pressing mechanism 4 and the pressing forces Ta ₁ and Tb ₁ in the gear axis direction generated by the pressing mechanism 4 are not canceled out, and an efficient differential limiting torque can be obtained.

In this case, when the sun gear 2C rotates faster than the internal gear 2D, a pressing force Ta is generated from the cam surface 401A to the cam surface 2013D via the cam follower 4B, and the internal gear 2D and the planetary carrier are generated in the sun gear 2C. Thrust force Ta ₁ is applied through 2A. Further, when the internal gear 2D rotates faster than the sun gear 2C, a pressing force Tb is generated from the cam surface 400A to the cam surface 2012D via the cam follower 4B, and the internal gear 2D and the planetary gear are generated on the sun gear 2C. Thrust force Tb ₁ (Tb ₁ > Ta ₁ ) is applied through carrier 2A.

[Effect of the first embodiment]
According to the first embodiment described above, the following effects can be obtained.

(1) The capacity of the pilot clutch 3B can be determined according to the torque capacity required when the sun gear 2C rotates faster than the internal gear 2D. For this reason, the number of clutch plates in the pilot clutch 3B can be reduced, and downsizing in the axial direction and cost reduction in the entire clutch can be achieved.

(2) Thrust force generated by the meshing between the planetary gears 2B, 2B,... And the sun gear 2C and the meshing between the planetary gears 2B, 2B,. Are not canceled out, and an efficient differential limiting torque can be obtained.

[Second Embodiment]
Next, a vehicle differential apparatus according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 4 shows the entire vehicle differential. FIG. 5 shows a pressing mechanism. 4 and 5, members that are the same as or equivalent to those in FIG.

  As shown in FIG. 4, the vehicle differential apparatus 101 according to the second embodiment of the present invention is similar to the vehicle differential apparatus 1 according to the first embodiment. Used as a center differential to distribute the driving force of the driving source to a differential device (not shown) on the front wheel side and a differential device (not shown) on the rear wheel side, and the driving torque (engine torque) of the driving source is used on the front wheel side And a differential mechanism 102 that differentially distributes to a pair of output shafts (not shown) on the rear wheel side, a differential limiting mechanism 103 that limits the differential of the differential mechanism 102, and a differential of the differential mechanism 102 A pressing mechanism 104 that generates a pressing force serving as a limiting force is generally configured.

  The differential mechanism 102 meshes with the planetary carrier 2A, a plurality of planetary gears 2B, 2B,... (Only one is shown) receiving the rotational force of the planetary carrier 2A, and the plurality of planetary gears 2B, 2B,. A sun gear 2C as an output member, an internal gear 2D as an output member meshing with a plurality of planetary gears 2B, 2B,... On the same axis as the sun gear 2C, and the internal gear 2D and the sun gear 2C / planetary A differential case 2E that accommodates a carrier 2A and a plurality of planetary gears 2B, 2B,.

The planetary carrier 2A is interposed between the sun gear 2C and the internal gear 2D and is rotatably disposed on the rotation axis O of the differential case 2E. The two inner and outer cylindrical bodies 40A ₁ have different outer diameters as a whole. , 40A ₂ .

Cylinder 40A ₁ have respective differing tube portion 42A~44A each other Kakusoto径, it is disposed on the inner peripheral portion of the planetary carrier 2A.

  The cylindrical portion 42A is arranged in the internal gear 2D (shown in FIG. 1), and the cylindrical portion 43A is arranged around the inner periphery of the sun gear 2C (shown in FIG. 1). The cylinder portion 44A is disposed so as to be interposed between the cylinder portion 42A and the cylinder portion 43A.

The outer peripheral surface of the cylindrical portion 42A, the helical spline engagement portion 420A is provided to form a helical gear is interposed between the internal gear 2D and the inner flange 451A of the cylindrical member 40A ₂ (described later). The cylindrical portion 42A, the second contact surface 421A which faces are provided on the first contact surface 452A of the inner flange 451A of the cylindrical member 40A ₂ (described later).

  The cylindrical body 41A includes a base portion 45A and a flange portion 46A. The cylindrical body 41A is interposed between the sun gear 2C and the internal gear 2D, and is entirely formed of a stepped cylindrical member having different inner and outer diameters. ing.

The base 45A is formed of a cylindrical member that opens in the direction of the rotation axis O of the planetary carrier 2A. The inner peripheral surface of the base portion 45A, and the fitting (engagement) to the cylindrical body 40A ₁ of the helical spline engagement portion 420A, and the thrust force in the axial direction by the driving force of the vehicle drive source (not shown) There is provided a helical spline fitting portion 450A that constitutes a thrust force generating portion to be generated together with the helical spline fitting 420A. Thereby, at the time of torque transmission between the cylinders 40A ₁ and 40A ₂ , a thrust force along the rotation axis O is generated between the cylinders 40A ₁ and 40A ₂ in the thrust generation part (helical spline fitting parts 420A and 450A). .

Further, a cylindrical body 40A ₁ that protrudes in the radial direction on the inner peripheral surface of the base portion 45A and extends along the rotation axis O direction by the thrust force generated between the helical spline fitting portions 420A and 450A in the drive mode or the coast mode. flange 451A among constituting the relative movement restricting portion for restricting the relative movement of 40A ₂ with the cylindrical portion 42A is provided.

  Here, the drive mode refers to a mode that is set when the forward torque of the vehicle is transmitted from the engine side to the pair of axles. The coast mode is a mode that is set when the forward torque of the vehicle is transmitted from the pair of axles to the engine side.

In the present embodiment, for example, when a thrust force is generated in the thrust force generating portion in a direction that restricts the relative movement of the cylindrical bodies 40A ₁ and 40A _{2 in} the drive mode, the planetary gears 2B, 2B,. The effect of increasing the differential limiting torque due to the thrust force generated along the rotation axis O in 2D can be nullified.

On the other hand, when the thrust force is generated in the thrust mode in the direction allowing the relative movement of the cylindrical bodies 40A ₁ and 40A _{2 in} the coast mode, the planetary gears 2B, 2B,. The effect of increasing the differential limiting torque by the thrust force generated along

The inner flange 451A is provided with a first abutment surface 452A that abuts against the second abutment surface 421A in the axial direction in a movement restricted state by the relative movement restriction portions of the cylindrical bodies 40A ₁ and 40A ₂ . Thus, the first contact surface 452A and the second contact surface 421A are brought into contact with each other, and are along the rotation axis O direction due to the thrust force generated between the helical spline fitting portions 420A and 450A in the drive mode or the coast mode. Relative movement is restricted.

  The flange portion 46A is formed by an annular member that is provided continuously to the base portion 45A and opens in the axial direction of the planetary carrier 2A. The outer diameter of the flange 46A is set to be larger than the outer diameter of the base 45A, and the inner diameter thereof is larger than the inner diameter of the base 45A.

  The planetary carrier 2A is provided with a gear accommodation support portion 22A that accommodates and supports the planetary gears 2B, 2B,... (Shown in FIG. 1) in a rotatable manner.

  The gear housing support portion 22A includes a first housing hole 220A and a second housing hole 221A, and is disposed across the base portion 45A and the flange portion 46A.

  The first accommodation hole 220A opens in the radial direction inside of the planetary carrier 2A (inner peripheral surface of the flange portion 46A) and both sides parallel to the rotation axis O, and is disposed in the flange portion 46A. The inner peripheral surface (torque transmission surface) of the first accommodation hole 220A is a first gear support surface made of a curvature surface that fits the tooth tip surfaces of the gear portions 20B, 20B,... (Described later) of the planetary gears 2B, 2B,. 2200A.

  The second accommodation hole 221A opens in one direction parallel to the radial outer side (the outer peripheral surface of the base 45A) and the axis O of the planetary carrier 2A, and communicates with the first accommodation hole 220A, and is disposed in the base 45A. . The inner peripheral surface (torque transmission surface) of the second accommodation hole 221A is a second gear support surface made of a curvature surface adapted to the tooth tip surfaces of the gear portions 21B, 21B,... (Described later) of the planetary gears 2B, 2B,. 2210A. The bottom surface of the second housing hole 221A is formed by a third gear support surface 2211A that slidably supports the axial end surfaces (free end surfaces) of the gear portions 21B, 21B,... Of the planetary gears 2B, 2B,. Yes.

The planetary gears 2B, 2B,... Have different pitch circle diameters D ₁ and D ₂ (D ₁ > D ₂ ) from each other (the torsion directions are the same). the gear specifications pitch circle diameter D _1, the gear portion 21B is a helical gear having with) the gear specifications pitch circle diameter D _2, in the first housing hole 220A and the second housing hole 221A of the planetary carrier 2A It is housed so that it can rotate.

  The gear portion 20B meshes with the sun gear 2C and is accommodated in the first accommodation hole 220A. And the gear part 20B is comprised so that the rotational force of the planetary carrier 2A can be transmitted to the left output shaft (output shaft for front axle connection) of FIG. 1 via the sun gear 2C.

  An annular thrust washer 105 located on the outer periphery of the sun gear 2C is interposed between the axial front end surface (free end surface) of the gear portion 20B and the inner flange 213E of the differential case 2E (rear case 21E). .

Number of teeth _{Z 1} of the gear portion 20B is set to the tooth number larger than the number of teeth _Z 2 of the gear portion 21B _(Z 1> _{Z 2).}

  The gear portion 21B meshes with the internal gear 2D and is accommodated in the second accommodation hole 221A. And the gear part 21B is comprised so that the rotational force of the planetary carrier 2A can be transmitted via the internal gear 2D to the output shaft (rear wheel side output shaft) which can be arrange | positioned at the right side of FIG.

  The sun gear 2C meshes with the gear portions 20B, 20B,... Of the planetary gears 2B, 2B,..., And is rotatably disposed on the axis of the internal gear 2D. Is formed by a cylindrical helical gear having the same axis. The sun gear 2C receives the rotational force from the gear portions 20B, 20B,... Of the planetary gears 2B, 2B,... And outputs it to an output shaft (front wheel side output shaft) that can be arranged on the left side of FIG. It is configured.

  A straight spline fitting portion 20C is provided on the inner peripheral surface of the sun gear 2C to connect the output shaft (not shown) on the front wheel side so as not to be relatively rotatable. On the outer peripheral surface of the sun gear 2 </ b> C, a helical spline fitting portion 21 </ b> C that forms the moving force conversion portion 24 together with the helical spline fitting portion 22 a of the intermediate member 45 is provided.

Pitch circle diameter _{D 3} and the number of teeth _{Z 3} of the sun gear 2C is the planetary gears 2B, 2B, ... of the gear portions 20B, 20B, ... large dimensions and number of teeth than the pitch circle diameter _{D 1} and the number of teeth _{Z 1} in the Is set.

  The internal gear 2D has a boss portion 20D and a gear portion 21D, meshes with the gear portions 21B, 21B,... Of the planetary gears 2B, 2B,..., And is rotatably arranged on the rotation axis O of the differential case 2E. The differential case 2E is attached to the rear case 21E via a ring bolt 106, and is entirely formed by a cylindrical helical gear. The internal gear 2D receives the rotational force from the gear portions 21B, 21B,... Of the planetary gears 2B, 2B,... And outputs it to the output shaft (rear wheel side output shaft) that can be arranged on the right side of FIG. It is configured.

  The boss portion 20D is disposed at a position facing the sun gear 2C via the planetary carrier 2A, and is entirely formed by a cylindrical body that opens in the direction of the rotation axis O of the differential case 2E. On the inner peripheral surface of the boss portion 20D, a straight spline fitting portion 200D for connecting a rear wheel side output shaft (not shown) in a relatively non-rotatable manner is provided. On the outer peripheral surface of the boss portion 20D, a flange portion 201D having a flange end surface facing the end surface opposite to the sun gear side end surface of the planetary carrier 2A is provided.

  The gear portion 21D meshes with the gear portions 21B, 21B,... Of the planetary gears 2B, 2B,... And is disposed around the outer periphery of the planetary carrier 2A. Is formed.

Pitch diameter D of the gear portion 21D ₄ is set to be larger dimensions and number of teeth than the pitch circle diameter D ₃ of the sun gear 2C. Thereby, the pitch diameter of the input side gear (the gear portions 20B, 20B,... And the gear portions 21B, 21B,... Of the planetary gears 2B, 2B,...) And the pitch of the output side gears (sun gear 2C and internal gear 2D). D ₃ / D ₁ <D ₄ / D ₂ is established with respect to the circle diameter, and rotation transmitted from the engine side to the internal gear 2D via the gear portions 21B, 21B,... Of the planetary gears 2B, 2B,. The torque becomes larger than the rotational torque transmitted to the sun gear 2C via the gear portions 21B, 21B,... Of the planetary gears 2B, 2B,. The number of teeth Z of the gear portion 21D ₄ is set to be larger dimensions and number of teeth than the number of teeth Z ₃ of the sun gear 2C.

  The differential case 2E includes an annular front case 20E that opens in two directions along the rotational axis O, and a cylindrical rear case 21E that is interposed between the front case 20E and the internal gear 2D. It is rotatably supported via 107 and is attached to the internal gear 2D via a ring bolt 106. The differential case 2E is formed as a whole by a hollow structure that houses the differential mechanism 2 and the differential limiting mechanism 3 together with the internal gear 2D.

  The front case 20E includes first to third case elements 46 to 48, is disposed on the base 42 side of the differential case 2E, and is attached to the rear case 21E with fastening bolts 108.

  The first case element 46 has a cylindrical portion 46a through which the base 42 is inserted, and a flange portion 46b that faces the armature 21 via the clutch mechanism 44, and is disposed on the inner peripheral side of the front case 20E. It is formed of a cylindrical member made of a magnetic material.

  The second case element 47 is disposed on the outer peripheral side of the front case 20 </ b> E, and the whole is formed of a cylindrical member made of a magnetic material such as soft iron like the first case element 46.

  The third case element 48 is interposed between the first case element 46 and the second case element 47, and is formed by an annular member for connecting the case element, which is entirely made of a nonmagnetic material such as stainless steel.

  The rear case 21E has an inner flange 213E interposed between the thrust washer 105 and the intermediate member 45, and is disposed between the differential mechanism 102 and the differential limiting mechanism 103. The rear case 21E is provided with a straight spline fitting portion 214E protruding from the inner peripheral surface thereof.

(Configuration of differential limiting mechanism 103)
The differential limiting mechanism 103 includes an electromagnetic clutch 41 that limits the differential of the differential mechanism 102, and is disposed between the inner peripheral surface of the differential case 2E (rear case 21E) and the outer peripheral surface of the sun gear 2C. The differential limiting mechanism 103 is configured to connect the sun gear 2C (the differential case 2E) and the internal gear 2D so that they can be intermittently (torque transmitted).

  The electromagnetic clutch 41 includes a fixing base 42, a differential case 2E that can rotate with respect to the base 42, a drive mechanism 43 that generates a clutch driving force in the differential case 2E, and an axis (rotation axis) of the drive mechanism 43. O) a clutch mechanism 44 that connects the sun gear 2C and the internal gear 2D that can rotate on and off, and an intermediate member 45 that can move toward the clutch mechanism 44.

  The base 42 is disposed on the left side of the differential case 2E in FIG. 4, and is entirely formed of a cylindrical member. The base 2 is provided with a housing space 2a for housing the electromagnetic coil 20.

  The drive mechanism 43 includes the electromagnetic coil 20 and the armature 21 and is disposed on the axis (rotation axis O) of the base 42. Then, the drive mechanism 43 moves the clutch plates adjacent to each other among the inner clutch plates 44a, 44a, ... and the outer clutch plates 44b, 44b, ... (described later) of the clutch mechanism 44 when the sun gear 2C and the internal gear 2D are rotated. It is configured to be pressed and frictionally slid.

  The electromagnetic coil 20 is housed in the housing space 42 a of the base 42. The electromagnetic coil 20 is configured to form a magnetic circuit across the base 42, the armature 21 and the front case 20E by energization, and generate an electromagnetic force for applying a moving force toward the base 42 to the armature 21. Has been.

  The armature 21 is disposed between the clutch mechanism 44 and the intermediate member 45 and is accommodated in the front case 20E. The whole is formed of an annular plate made of a magnetic material such as iron. The armature 21 is configured to receive the electromagnetic force of the electromagnetic coil 20 and move along the rotation axis O of the differential case 2E to the clutch mechanism 44.

  The clutch mechanism 44 includes inner clutch plates 44a, 44a,... And outer clutch plates 44b, 44b,... That can be frictionally engaged with each other by the movement of the armature 21 driven by the drive mechanism 43, and the armature 21 and the front case 20E. And is accommodated in the rear case 21E. In the clutch mechanism 44, the clutch plates adjacent to each other among the inner clutch plates 44a, 44a,... And the outer clutch plates 44b, 44b,. The gear 2D (difference case 2E) is configured to be intermittent.

  The inner clutch plates 44a, 44a,... And the outer clutch plates 44b, 44b,... Are alternately arranged along the rotational axis O of the differential case 2E, and are entirely formed by an annular friction plate.

  The inner clutch plates 44a, 44a,... Have straight spline fitting portions 440a, 440a,... On the inner periphery thereof, are movably disposed on the rotation axis O of the differential case 2E, and are straight spline fitting portions 440a. , 440a,... Are connected to a straight spline fitting portion 22b (described later) of the intermediate member 45 in a relatively non-rotatable manner.

  The outer clutch plates 44b, 44b,... Have straight spline fitting portions 440b, 440b,... On the outer periphery thereof, are movably disposed on the rotation axis O of the differential case 2E, and the straight spline fitting portions 440b, 440b,... Are connected to the straight spline fitting portion 214E of the rear case 21E in a relatively non-rotatable manner.

(Configuration of the pressing mechanism 104)
FIG. 5 shows a pressing mechanism. The pressing mechanism 104 includes the sun gear 2C and the intermediate member 45, and is accommodated in the differential case 2E. The pressing mechanism 104 generates pressing forces Ta and Tb (Ta> Tb = 0) as differential limiting forces for the differential mechanism 102, and these pressing forces are used for differential rotation of the sun gear 2C and the internal gear 2D. It is configured to vary depending on the direction.

  The intermediate member 45 has a base portion 22 and a flange portion 23, is disposed on the outer periphery of the sun gear 2C, and is accommodated in the differential case 2E, and is entirely formed of a nonmagnetic material such as stainless steel. The intermediate member 45 is configured to receive the rotational force of the sun gear 2 </ b> C and move toward the clutch mechanism 44.

  The base 22 is formed by a cylindrical member that opens in the axial direction. A helical spline fitting portion 22a fitted (engaged) corresponding to the helical spline fitting portion 21C of the sun gear 2C is formed on the inner peripheral surface of the base portion 22, and inner clutch plates 44a, 44a,. Straight spline fitting portions 22b corresponding to the straight spline fitting portions 440a, 440a,.

  The helical spline fitting portion 22a forms a moving force converting portion 24 together with the helical spline fitting portion 21C, and is configured to convert the rotational force of the sun gear 2C into moving force to the clutch mechanism 44. The helical spline fitting portion 22a is twisted so that the inner clutch plates 44a, 44a, ... and the outer clutch plates 44b, 44b, ... are not frictionally engaged with each other when the electromagnetic coil 20 is switched from the energized state to the non-energized state. An angle (for example, 45 °) is set.

  The twist angles of the helical spline fitting portions 22a and 21C are appropriately changed according to the number of clutch plates, the dimension from the rotation axis O to the spline engagement point, and the like.

  The flange 23 is interposed between the inner flange 213E of the rear case 21E and one end face of the armature 21 (the end face opposite to the clutch mechanism side end face) and is disposed at one end of the intermediate member 45 in the axial direction. 22 is integrally provided on the outer peripheral surface.

  On the clutch mechanism side end surface of the flange 23, the armature 21 is moved in a direction in which the inner clutch plates 44a, 44a,... And the outer clutch plates 44b, 44b,. The pressing part 23a which presses is provided.

[Operation of Differential Device 101 for Vehicle]
Next, the operation of the vehicle differential shown in the present embodiment will be described with reference to FIGS. 4 and 3A and 3B. FIG. 3A shows a thrust force generation state in the drive mode, and FIG. 3B shows a thrust force generation state in the coast mode.

  As shown in FIG. 4, when torque from the engine side of the vehicle is input to the planetary carrier 2A, the planetary carrier 2A is rotationally driven around the rotation axis O. When the planetary carrier 2A is rotationally driven, this rotational force is transmitted to the planetary gears 2B, 2B,..., And from the gear portions 20B, 20B,. Are transmitted to the internal gear 2D from the gear portions 21B, 21B,. In this case, the sun gear 2C is spline-fitted to the front wheel side output shaft and the inner gear 2D is spline fitted to the rear wheel side output shaft, respectively, so that torque from the engine side is transmitted to the planetary carrier 2A and the planetary gears 2B, 2B,. Further, it is transmitted to the left and right (front and rear wheel side) output shafts via the sun gear 2C and the internal gear 2D.

Here, when the vehicle is in a straight traveling state and no slip occurs between the front and rear wheels between the road surface and the torque from the engine side is transmitted to the planetary carrier 2A, the planetary carrier 2A is rotated about the rotation axis O. , And the planetary gears 2B, 2B,... Revolve around the center axis of the sun gear 2C and the internal gear 2D without rotation, and the planetary gears 2B, 2B,. Since it rotates together with the planetary carrier 2A, the torque from the engine side is differential at the time of static friction based on the distribution ratio of D ₃ / D ₁ (front): D ₄ / D ₂ (rear) to the front and rear output shafts. Within the limit torque distribution, the road surface reaction force is immediately imbalanced and transmitted to the front and rear output shafts without loss, and the front and rear output shafts rotate at the same rotational speed.

  On the other hand, when slip occurs between one of the front and rear wheels of the vehicle and the road surface, the output side gear is operated by the following actions (1) and (2) with the engine torque being input to the planetary carrier 2A. Differential limiting torque is generated in (sun gear 2C and internal gear 2D).

(1) When the planetary gears 2B, 2B,... Rotate in a state where torque is input, the tooth tip surfaces of the planetary gears 2B, 2B,... (Gear portions 20B, 20B,... And gear portions 21B, 21B,...) Slides on the first gear support surface 2200A and the second gear support surface 2210A of the planetary carrier 2A (the first accommodation hole 220A and the second accommodation hole 221A), and the first gear support surface 2200A and the second gear support surface 2210A. And the planetary gears 2B, 2B,... Generate frictional resistance, and differential friction torque is generated in the sun gear 2C and the internal gear 2D by these frictional resistances.

  Further, the rotation of the planetary gears 2B, 2B,... With the torque applied thereto causes each gear (planetary gears 2B, 2B,..., The sun gear 2C, and the internal gear 2D) to thrust along the rotation axis O on the gear meshing surface. Force is generated. In this case, the planetary gears 2B, 2B,... (Gear portions 21B, 21B,...) Have axially leading end surfaces on the third gear support surface 2211A of the planetary carrier 2A (second housing hole 201a) or the inner flange 213E of the rear case 21E. And slide through the thrust washer 105. At this time, frictional resistance is generated between the sliding portions, and differential limiting torque is generated in the sun gear 2C and the internal gear 2D due to the frictional resistance.

  In the present embodiment, the planetary carrier 2A generates a thrust force along the rotation axis O direction, and the thrust force along the axis O direction of the cylinders 40A and 41A in the vehicle drive mode shown in FIG. And a relative movement restricting portion for restricting relative movement by.

  Therefore, when a thrust force is generated in the cylinder 40A in the left direction in FIG. 4 and in the cylinder body 41A in the right direction in FIG. 4 in the thrust force generating portion in the drive mode, the first contact surface 452A and The cylinders 40A and 41A move in the direction in which the second contact surfaces 421A are pushed together, and the relative movement of the cylinders 40A and 41A is restricted. Thereby, the effect of increasing the differential limiting torque due to the thrust force generated along the rotation axis O in each gear (the planetary gears 2B, 2B,..., The sun gear 2C, and the internal gear 2D) can be nullified. The increase in the bias of the vehicle is suppressed during the drive mode, and the bias adjustment limited to the drive mode can be performed.

  On the other hand, when a thrust force is generated in the cylindrical body 40A in the right direction of FIG. 4 and in the cylindrical body 41A in the coasting mode of the vehicle shown in FIG. The cylindrical bodies 40A and 41A move in the direction in which the first contact surface 452A and the second contact surface 421A are separated from each other, and the relative movement of the cylinders 40A and 41A is not restricted. Thereby, due to the thrust force generated between the helical spline fitting portions 420A and 450A, the thrust force generated along the rotation axis O in each gear (the planetary gears 2B, 2B,..., The sun gear 2C, and the internal gear 2D). An effect of increasing the differential limiting torque can be obtained.

(2) When the electromagnetic coil 20 of the drive mechanism 43 is energized, a magnetic circuit is formed across the base 42 and the front case 20E, the rear case 21E, and the armature 21, and the armature 21 is moved to the electromagnetic coil side (base 42 side) by the electromagnetic force. Move to. Due to the movement of the armature 21, the differential limiting mechanism 103 (the inner clutch plates 44a, 44a,... And the outer clutch plates 44, 44b,... Of the clutch mechanism 44) is pressed toward the base 42, and the inner clutch plates 44a, 44a,. 44a, ... and the outer clutch plates 44b, 44b, ... are relatively close to each other and frictionally engage with each other.

  In this case, a primary clutch force is generated by frictional engagement between the inner clutch plates 44a, 44a, ... and the outer clutch plates 44b, 44b, ..., and the differential clutch 2E and the sun gear 2C are caused by this primary clutch force. That is, the sun gear 2C and the internal gear 2D are connected to each other via the inner clutch plates 44a, 44a,... And the outer clutch plates 44b, 44b,. Thereby, differential limiting torque is generated in the sun gear 2C and the internal gear 2D.

Here, when the planetary carrier 2A is rotated in the direction indicated by the arrow in FIG. 4 by the drive torque of the drive source, the sun gear 2C and the internal gear 2D have a distribution ratio of D ₄ / D ₂ : D ₃ / D _1. The corresponding primary generation torque is received. At this time, in the moving force converting portion 24 (helical spline fitting portions 22a and 21C) of the intermediate member 45, the sun gear 2C has a thrust force toward the planetary carrier 2A, and the intermediate member 45 has a force toward the armature 21. Each of the thrust forces acts at a magnitude proportional to the magnitude of the primary generated torque.

For this reason, the rotational force of the sun gear 2C is converted into a moving force to the clutch mechanism 44 by the moving force conversion unit 24, that is, a pressing force Ta that becomes a differential limiting force with respect to the differential mechanism 102 is generated. The intermediate member 45 moves to the clutch mechanism 44 side and presses the armature 21 in a direction in which the inner clutch plates 44a, 44a,... And the outer clutch plates 44b, 44b,. A secondary clutch force is generated by the pressing of. Thereby, the sun gear 2C and the internal gear 2D receive the secondary generated torque according to the distribution ratio of D ₄ / D ₂ : D ₃ / D ₁ via the clutch mechanism 44 and the intermediate member 45. The sun gear 2 </ b> C and the internal gear 2 </ b> D receive the amplified torque by repeating such a cycle, and the shortage of the differential limiting torque can be compensated.

On the other hand, when the planetary carrier 2A is rotated in the direction opposite to the direction indicated by the arrow in FIG. 4 by the drive torque of the drive source, the sun gear 2C and the internal gear 2D are D ₄ / D ₂ : D ₃ / D ₁ . The primary generated torque corresponding to the distribution ratio is received. At this time, in the moving force converting portion 24 (helical spline fitting portions 22a and 21C) of the intermediate member 45, the sun gear 2C has a thrust force opposite to the planetary carrier 2A, and the intermediate member 45 has the armature 21. The thrust force to the opposite side acts in proportion to the magnitude of the primary generated torque.

  For this reason, the intermediate member 45 moves away from the armature 21, and the rotational force of the sun gear 2 </ b> C is not converted into the moving force to the clutch mechanism 44 by the moving force conversion unit 24, that is, the differential with respect to the differential mechanism 102. The pressing force Tb (Tb = 0) serving as the limiting force is not generated, and the secondary clutch force due to the pressing to the armature 21 is not generated.

[Effect of the second embodiment]
According to the second embodiment described above, the following effects can be obtained in addition to the effects of the first embodiment.

  In planetary carrier 2A, relative movement of cylinders 40A and 41A is restricted in the vehicle drive mode, and differential limitation due to thrust force generated in each gear (planetary gears 2B, 2B,..., Sun gear 2C, and internal gear 2D). The torque increasing effect can be invalidated. As a result, the increase in the bias of the vehicle is suppressed, and the bias adjustment limited to the drive mode can be performed.

[Third embodiment]
Next, a vehicle differential apparatus according to a third embodiment of the present invention will be described with reference to FIGS. FIG. 6 shows a main part of the vehicle differential. FIG. 7 shows the pressing mechanism. 6 and 7, the same or equivalent members as those in FIG. 4 are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 6, the pressing mechanism 201 of the vehicle differential shown in the third embodiment is characterized in that the intermediate member 45 is cam-coupled to the sun gear 2C.

  Therefore, as shown in FIGS. 7A and 7B, an annular first cam 202 is provided on the inner peripheral surface of the intermediate member 45 along the circumferential direction thereof. The first cam 202 is formed by a thick part having two types of cam surfaces 202a and 202b that are parallel to each other in the rotation direction of the intermediate member 45 and have different gradients. The cam surface 202a is a sloping inclined surface inclined to one side in the circumferential direction of the intermediate member 45, and the cam surface 202b is a plurality of steep inclined surfaces inclined to the other circumferential direction of the intermediate member 45. Is formed.

  An annular second cam 203 is provided along the circumferential direction on the outer peripheral surface of the sun gear 2C. The second cam 203 is formed by a thick portion having two types of cam surfaces 203a and 203b which are parallel to each other in the rotational direction of the sun gear 2C and have different gradients. The cam surface 203a is a sloping inclined surface inclined to one side in the circumferential direction of the sun gear 2C, and the cam surface 203b is a steep inclined surface inclined to the other circumferential side of the sun gear 2C. Is formed.

  The cam surface 203a of the second cam 203 faces the cam surface 202a of the first cam 202, and the internal gear 2D rotates relative to the sun gear 2C in the direction opposite to the arrow direction shown in FIG. The first cam 202 is configured to contact the cam surface 202a. The cam surface 203b of the second cam 203 faces the cam surface 202b of the first cam 202, and when the cam surface 202b of the first cam 202 rotates relative to the sun gear 2C in the arrow direction shown in FIG. It is comprised so that it may contact | abut.

In the present embodiment, when the sun gear 2C is rotating faster than the internal gear 2D when the electromagnetic coil 20 is energized, as shown in FIG. 1 pressing force Sa is generated to the cam surface 202b of the cam 202, the thrust force Sa ₁ is applied to the intermediate member 5. Further, when the internal gear 2D rotates faster than the sun gear 2C when the electromagnetic coil 20 is energized, as shown in FIG. 7 (b), the first cam 202 from the cam surface 203a of the second cam 203. A pressing force Sb to the cam surface 202 a is generated, and a thrust force Sb ₁ is applied to the intermediate member 45.

[Effect of the third embodiment]
According to the third embodiment described above, the same effect as that of the first embodiment can be obtained.

  As mentioned above, although the vehicle differential gear of this invention was demonstrated based on said embodiment, this invention is not limited to said embodiment, In various aspects in the range which does not deviate from the summary. For example, the following modifications are possible.

In the present embodiment, the pitch circle diameter of the input side gear (the planetary gears 2B, 2B,..., And the gear portions 21B, 21B,...) And the output side gear (the sun gear 2C and the internal gear 2D). ), The case where D ₃ / D ₁ <D ₄ / D ₂ is established is described. However, the present invention is not limited to this, and the input side gears (planetary gears 2B, 2B,... gear portions 20B, 20B, ... and gear portions _{21B, 21B, ...) D 3} / D 1 between the pitch circle diameter of the pitch circle diameter of the output side gear (sun gear 2C and the internal gear 2D) _{of> D} 4 / dimensioned to D ₂ is satisfied may be set to a pitch circle diameter of the gear.

DESCRIPTION OF SYMBOLS 1 ... Vehicle differential device, 2 ... Differential mechanism, 2A ... Planetary carrier, 20A ... Carrier base part, 21A ... Carrier collar part, 200A ... Straight spline fitting part, 22A ... Gear accommodation support part, 220A ... 1st accommodation Hole, 2200A ... first gear support surface, 2201A ... inner flange, 221A ... second accommodation hole, 2210A ... second gear support surface, 2211A ... third gear support surface, 2B ... planetary gear, 20B, 21B ... gear part, 2C ... sun gear, 20C ... straight spline fitting portion, 21C ... collar portion, 210C ... fourth gear support surface, 22C ... helical spline fitting portion, 2D ... internal gear, 20D ... boss portion, 200D ... straight spline fitting Part, 201D ... collar part, 2010D ... straight spline fitting part, 2011D ... cam hole, 2012D, 2013D ... cam surface, 21D Gear part, 210D ... collar part, 211D ... concave hole, 2E ... differential case, 20E ... front case, 200E ... large diameter cylindrical part, 2000E ... stepped part, 201E ... small diameter cylindrical part, 2010E ... component insertion port, 2011E ... Straight spline fitting part, 21E ... rear case, 210E ... first case element, 2100E ... collar part, 211E ... second case element, 2110E ... collar part, 212E ... third case element, 213E ... inner flange, 214E ... straight spline Fitting part, 3 ... differential limiting mechanism, 3A ... electromagnetic clutch, 30A ... electromagnetic coil, 31A ... armature, 3B ... pilot clutch, 30B ... inner clutch plate, 31B ... outer clutch plate, 4 ... pressing mechanism, 4A ... cam 40A ... cam hole, 400A, 401A ... cam surface, B ... Cam follower, 5 ... Thrust washer, 6 ... Sphere, 7, 8 ... Thrust washer, 9 ... Needle bearing, 10 ... Bearing (ball bearing), 11 ... Bearing (needle bearing), 20 ... Electromagnetic coil, 21 ... Armature, 22 ... Base part, 22a ... Helical spline fitting part, 22b ... Straight spline fitting part, 23 ... collar part, 23a ... pressing part, 24 ... moving force conversion part, 101 ... vehicle differential device, 102 ... differential mechanism, 103 ... differential limiting mechanism, 104 ... pressing mechanism, 105 ... thrust washer 106 ... ring bolt, 107 ... bearing, 108 ... fastening bolt, _40A 1, 40A 2 _... cylinder, 41 ... electromagnetic clutch 42 ... base, 42a ... accommodating space, 42A ... cylindrical part, 420A ... helical spline fitting part, 421A ... second contact surface, 43 ... drive mechanism, 3A, 44A ... cylinder part, 44 ... clutch mechanism, 44a ... inner clutch plate, 440a ... straight spline fitting part, 44b ... outer clutch plate, 440b ... straight spline fitting part, 40A, 41A ... cylindrical body, 45 ... middle 452A ... first contact surface, 453A ... collar, 45A ... base, 450A ... helical spline fitting part, 451A ... inner flange, 46 ... first case element, 46a ... cylindrical part, 46b ... collar, 47 2nd case element, 48 ... 3rd case element, 201 ... Pressing mechanism, 202 ... 1st cam, 202a, 202b ... Cam surface, 203 ... 2nd cam, 203a, 203b ... Cam surface, C ... Annular space, O ... Rotation axis

Claims (4)

A differential mechanism that has a pair of output members set to a torque distribution ratio that makes each distribution torque different from each other, and distributes the drive torque of the drive source to the pair of output members;
A vehicle differential apparatus comprising: a pressing mechanism that generates a pressing force that serves as a differential limiting force for the differential mechanism and varies the pressing force according to a differential rotation direction of the pair of output members.   The pressing mechanism includes a first cam that rotates by receiving a rotational force transmitted from one output member of the pair of output members via the clutch, and the first cam that faces the first cam. 2. The vehicle difference according to claim 1, comprising a cam mechanism having a second cam capable of relative rotation, wherein each of the first cam and the second cam has two types of slow and steep cam surfaces having different slopes. Moving device.   The pressing mechanism includes a pressing member that rotates by receiving a rotational force transmitted from one output member of the pair of output members via the clutch, and the pressing member is the other of the pair of output members. The vehicle differential device according to claim 1, wherein the differential member is connected to the output member by helical spline fitting. The pressing mechanism includes a pressing member that rotates by receiving a rotational force transmitted from one output member of the pair of output members via the clutch, and the pressing member is the other of the pair of output members. Connected to the output member by a cam connection,
The pressing member has two kinds of slow and steep cam surfaces that are parallel to each other in the rotational direction and have different gradients,
2. The vehicle differential device according to claim 1, wherein the other output member has two types of cam surfaces that face the two types of cam surfaces and that have different gradients.

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