JP2017044248A - Differential device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a differential device capable of easily changing a locking rate.SOLUTION: A cam ring 51 includes a cam mechanism to a cover body portion 13, and engaged with a pressure ring 53 in a rotating direction relatively movably in an axial direction. The cam mechanism makes the cam ring 51 engage with the cover body portion 13 in the rotating direction, applies fastening force by generating thrust force to the cover body portion 13, on the cam ring 51 by relative rotation in the rotating direction of the cam ring 51 to the cover body portion 13, and a contact state to a cam face 25a of a cam follower face 61a is changed by changing the cam ring 51 and changing inclination of the cam follower face 61a, thus a locking rate is changed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a differential device used for an automobile or the like.

  As a conventional differential device, for example, there is one having a differential limiting mechanism shown in FIG.

  The differential apparatus shown in FIG. 11 has the same structure as that of Patent Document 1. The differential limiting mechanism of the differential device includes a friction clutch 106 in which an outer plate 103 engaged with the differential case 101 side and an inner plate 105 engaged with the side gear side are alternately arranged. It is interposed between the side gear 107 and the pressure ring 109 in the axial direction.

  When the differential case 101 receives a rotational input, drive torque is transmitted to the pressure ring 109 engaged with the differential case 101, and torque is transmitted to the pinion shaft 113 via the cam surface 111. By this torque transmission, the pinion gear 115 and the side gear 107 rotate together. Torque is transmitted from the side gear 107 via the left and right axle shafts, and the left and right wheels are rotationally driven.

  When the cam surface 111 contacts the pinion shaft 113 in the rotational direction, the pressure ring 109 moves to the friction clutch 106 side by the cam action. By this movement, the friction clutch 106 is fastened between the pressure ring 109 and the side wall 101a.

  In this case, as the torque transmitted from the differential case 101 to the pressure ring 109 increases, the thrust force by the cam surface 111 increases, so the friction clutch 106 increases the fastening force according to the torque. Due to the fastening force of the friction clutch 106, the side gear 107 and the differential case 101 are frictionally engaged, and differential restriction between the left and right side gears is performed. As described above, the differential limiting force increases as the torque increases.

  Torque is transmitted to the left and right wheels while performing differential restriction in accordance with torque increase.

  In a differential apparatus equipped with such a differential limiting mechanism, it is necessary to change the pressure ring 109 and the pinion shaft 113 or change the number of plates of the friction clutch 106 in order to change the lock rate. It was necessary and a great deal of effort was required for the change.

JP 2005-098385 A

  The problem to be solved is that a lot of work is required to change the lock rate, and a great deal of labor is required for the change.

  In order to make it possible to easily change the lock rate, the present invention engages with the differential case and the pinion shaft, enables rotation of the differential case as revolution of the pinion gear, and transmits torque to the differential case. A differential device including a pressing member that moves according to a torque or torque output from the differential case and applies a fastening force to a friction member for limiting differential rotation of the side gear according to the fastening force. Is composed of a main body part and a lid part that closes an end part of the main body part, and the pressing member is engaged with the first pressing member that engages with the lid part and the second pinion shaft. A pressing member, and the first pressing member includes a cam mechanism between the first pressing member and the lid body, and is rotatable relative to the second pressing member in the axial direction. The cam mechanism causes the engagement of the first pressing member with respect to the lid body portion in the rotation direction and relative to the lid body portion of the first pressing member in the rotation direction. The first pressing member is rotated to generate a thrust force with respect to the lid body portion to give the fastening force.

  Since the present invention has the above-described configuration, the first pressing member generates a thrust force on the lid body portion by relative rotation in the rotation direction with respect to the lid body portion, and gives a fastening force to the friction member. The differential rotation of the side gear can be limited according to the fastening force.

  In addition, the characteristics of the cam mechanism can be changed by changing the first pressing member, and the lock rate can be easily changed.

It is sectional drawing of a differential apparatus. Example 1 It is sectional drawing of a main-body part. Example 1 It is sectional drawing of the cover body part of a differential case. Example 1 It is principal part sectional drawing which shows the cam of the cover body part of a differential case. Example 1 It is a front view of the inner surface side of the lid part of the differential case. Example 1 It is sectional drawing of a cam ring. Example 1 It is a principal part expanded sectional view which shows the relationship between the cam protrusion of a cam ring, and a cam surface. Example 1 It is a front view of a cam ring. Example 1 It is principal part sectional drawing of a pressure ring. Example 1 It is principal part explanatory drawing which shows engagement with a pressure ring and a pinion shaft. Example 1 It is principal part sectional drawing of a differential apparatus. (Conventional example)

  The first pressing member is provided with a cam mechanism between the first pressing member and the lid body portion, and can be relatively moved in the axial direction relative to the second pressing member for the purpose of making it possible to easily change the lock rate. Engaging in the rotation direction, the cam mechanism causes the engagement of the first pressing member with the lid body portion in the rotation direction and the rotation direction of the first pressing member with respect to the lid body portion. This is realized by generating a thrust force against the lid body portion on the first pressing member by relative rotation and applying the fastening force.

  The cam mechanism may include a hole portion formed in the lid body portion and provided with a cam surface, and a cam protrusion portion formed in the first pressing member and fitted in the hole portion.

  The cam surface may be a curved surface.

  An urging member that urges the first pressing member toward the second pressing member may be provided between the first pressing member and the lid portion.

  1 is a sectional view of a differential device according to an embodiment of the present invention, FIG. 2 is a sectional view of a main body, FIG. 3 is a sectional view of a lid body of a differential case, and FIG. 4 is a sectional view of a lid body of the differential case. FIG. 5 is a front view of the inner surface side of the lid portion of the differential case, FIG. 6 is a sectional view of the cam ring, and FIG. 7 is a diagram showing the relationship between the cam protrusion of the cam ring and the cam surface. FIG. 8 is a front view of the cam ring, FIG. 9 is a cross-sectional view of the main part of the pressure ring, and FIG. 10 is an explanatory view of the main part showing the engagement between the pressure ring and the pinion shaft. In the following description, the axial direction means the direction of the rotational axis of the differential case, and the rotational direction means the direction around the rotational axis of the differential case.

  As shown in FIG. 1, the differential device 1 includes a differential case 3, a pair of side gears 5 and 7, and a pinion gear 9.

  The differential case 3 includes a main body portion 11 and a lid portion 13.

  As shown in FIGS. 1 and 2, the main body 11 accommodates a pinion gear, each side gear, and the like, and is integrally provided with a main body flange portion 15 on one side of the main body peripheral wall portion 14 and a main body end wall on the other side. The part 17 is provided integrally. The body peripheral wall portion 14 is provided with a through hole 16 for lubrication.

  A boss portion 19 is integrally projected on the main body end wall portion 17, and an outer peripheral surface of the boss portion 19 serves as a bearing support portion 19a.

  A fastening receiving surface 17 a is provided on the inner surface of the main body end wall portion 17, and a concave portion 17 b for rotation support is formed in a circular shape at the inner lower end of the main body end wall portion 17.

  As shown in FIGS. 1 and 3 to 5, the lid 13 closes the end of the main body 11. The end of the main body 11 is an opening end in the axial direction of the main body 11. The lid body portion 13 is integrally provided with a lid flange portion 21 on the outer peripheral portion, a boss portion 23 is integrally projected on the inner peripheral portion, and the outer peripheral surface of the boss portion 23 is a bearing support portion 23a. A concave portion 13a for rotation support is formed in a circular shape on the inner periphery on the inner surface side of the lid portion 13.

  A counterbore 13b is formed around the outer periphery of the recess 13a in the lid 13 in a circular shape. A hole 25 is formed in the counterbore 13b. The holes 25 are formed at four locations at regular intervals in the circumferential direction, for example, 90 degrees in the rotational direction. Each hole portion 25 is formed in a substantially rectangular shape when viewed from the front, and penetrates the outer surface of the lid portion 13 in the axial direction.

  A pair of cam surfaces 25a are formed in the hole 25 so as to oppose each other in the rotational direction, and the cam surfaces 25a constitute a cam mechanism together with a cam protrusion described later. The cam surface 25a is formed as a curved surface, and the pair of cam surfaces 25a is set so that the distance from the counterbore 13b side to the outer surface side of the lid body portion 13 is gradually narrowed.

  The curvature of the cam surface 25a is a constant arc, and the center of curvature of the arc is located slightly on the left side in the axial direction from the outer surface of the lid 13 (the right surface in FIG. 4). In this case, the terminal portion on the outer surface side of the lid portion 13 of the cam surface 25a is linearly formed along the axial direction. Therefore, formation of each cam surface 25a with respect to each hole 25 is facilitated.

  In addition, the terminal part of the outer surface side of the cover body part 13 of the cam surface 25a can also be formed as a part of the arc as it is, and the center of the arc of the arc is on the outer surface of the cover body part 13 or outside the outer surface. It can also be set.

  Furthermore, the curvature of the curved surface of the cam surface 25a can be set so as to gradually increase from the counterbore 13b side to the outer surface side of the lid portion 13. In addition, the lock rate can be changed by moving forward and backward by changing the setting of the pair of cam surfaces 25a in the rotation direction.

  A spring recess 31 is formed between the hole portions 25 on the inner surface side in the axial direction of the lid portion 13. The spring recesses 31 are equally arranged in the circumferential direction, and four spring recesses 31 are formed in this embodiment.

  The lid flange portion 21 is combined with the main body flange portion 15 and fastened and fixed by bolts. The lid body portion 13 is attached to the main body portion 11 to close the end portion of the main body portion 11, thereby forming the differential case 3. A ring gear that receives torque input from the drive pinion gear is fastened and fixed to the flange portion including the main body flange portion 15 and the lid flange portion 21.

  The side gears 5 and 7 are provided with gear portions 39 and 41 on the front side of the circumferential gear main body portions 35 and 37 and are bevel gears. On the back surfaces of the gear portions 39 and 41, convex portions 39a and 41a for rotational fitting are formed in a circular shape. The convex portions 39 a and 41 a are rotatably supported by the concave portions 17 b and 13 a of the differential case 3.

  Spline-like engaging portions 43 and 44 are provided on the outer periphery of the gear main body portions 35 and 37 of the side gears 5 and 7. The engaging portions 43 and 44 are provided from the gear main body portions 35 and 37 to the gear portions 39 and 41.

  An axle shaft, which is a pair of shafts that pass through the boss portions 19 and 23 of the differential case 3, is splined to the side gears 5 and 7.

   The pinion gear 9 is a four-pinion type provided with four pieces, is rotatably supported by a pinion shaft 45 and meshes with the side gears 5 and 7. The pinion shaft 45 is not formed as an integral spider, but is formed by a cross combination of two shaft members 47 and 49.

  However, the pinion shaft 45 can also be formed in an integral spider shape. In this case, in order to make it possible to incorporate the pinion shaft 45, the pressure ring described later is a separate split type with the pinion shaft 45 interposed therebetween.

  The shaft members 47 and 49 have the same shape, and are formed with engagement recesses 47a and 49a for engagement at the center in the length direction.

  The cross-sectional shape of the two shaft members 47 and 49 is circular, and the two shaft members 47 and 49 are coupled so as to be engaged with each other by the alignment recesses 47a and 49a, thereby forming a cross pinion shaft 45.

  Each pinion gear 9 meshes with each side gear 5, 7. This meshing enables torque transmission between the differential case 3 and the side gears 5, 7 and allows relative rotation between the side gears 5, 7.

  The pinion shaft 45, the pinion gear 9, and the side gears 5 and 7 are accommodated in the main body portion 11 of the differential case 3, and the main body portion 11 further includes a cam ring 51, which is a first pressing member, and a second pressing member as a pressing member. A pressure ring 53 as a pressing member and multi-plate friction clutches 55 and 57 as a friction member are accommodated.

  As shown in FIGS. 1 and 6 to 8, the cam ring 51 is engaged with the lid portion 13, is movable relative to the pressure ring 53 in the axial direction, and is engaged in the rotational direction.

  The cam ring 51 includes a ring-shaped main body 59, and a counterbore 59a and a fitting hole 59b are formed in the main body 59. The counterbore 59a is fitted to the side gear 7, and the fitting hole 59b is fitted to the inner peripheral side of the counterbore 13b of the lid portion 13.

  Four cam protrusions 61 are formed on one side surface of the cam ring 51 at equal intervals in the rotation direction of the differential case 3, and a pressing surface 62 is formed on the other side surface.

  The cam protrusion 61 is fitted into the hole 25 to cause the cam surface 25a to engage in the rotation direction of the differential case 3. As shown in FIG. 7, the cam protrusion 61 is formed in a trapezoidal shape into the hole 25 when viewed from the radial direction, and inclined cam follower surfaces 61 a are formed on both sides of the differential case 3 in the rotational direction. The cam follower surface 61a of the cam protrusion 61 is engaged with the cam surface 25a to constitute the cam mechanism.

  The cam follower surface 61a and the cam surface 25a are relative, and in order to obtain a set cam function, the cam follower surface 61a is a curved surface, the cam surface 25a is a linear inclined surface, or the cam follower surface 61a and the cam surface Both 25a can also be formed as curved surfaces.

  Further, even if the cam follower surface 61a is formed as a linear surface along the axial direction without being inclined, a similar cam mechanism can be configured by the tip of the cam projection 61 coming into contact with the curved cam surface 25a. it can.

  On the outer periphery of the cam ring 51, an engaging protrusion 51a is provided so as to protrude in the radial direction. The engaging protrusion 51a is movable relative to the pressure ring 53 in the axial direction and engages in the rotational direction.

  With this structure, the cam mechanism using the cam follower surface 61a and the cam surface 25a causes the cam ring 51 to engage with the lid body portion 13 in the rotational direction and causes the cam ring 51 to rotate relative to the lid body portion 13 in the rotational direction. A thrust force is generated on the lid portion 13 to apply a fastening force to the friction clutches 55 and 57.

  A coil spring 63 is elastically contacted to the side surface of the cam ring 51, and the coil spring 63 is accommodated in each spring recess 31 of the lid body portion 13. Therefore, an urging member that urges the cam ring 51 toward the pressure ring 53 is provided between the cam ring 51 and the lid portion 13.

  The pressure ring 53 is integrally formed in a cylindrical shape and is engaged with the pinion shaft 45. Engagement of the pressure ring 53 with the pinion shaft 45 is performed by an engagement hole 65. The engagement holes 65 are formed at four locations in the circumferential direction. The engagement hole 65 is formed as an elongated hole in the axial direction with respect to the circular cross section of the pinion shaft 45, and allows the pinion shaft 45 to be incorporated.

  That is, when the cross of the two shaft members 47 and 49 is combined in the pinion shaft 45, the cross of the two shaft members 47 and 49 is assembled using the axial length of the engagement hole 65. .

  For example, both end portions of the shaft member 47 are inserted into the engagement holes 65 opposed in the radial direction so as to be positioned at the end portions in the longitudinal direction of the engagement holes 65, and the other shaft member 49 on the side intersecting the shaft member 47. The pair of engagement holes 65 are inserted on the other end side in the longitudinal direction.

  At this time, the four pinion gears 9 are arranged inside the pressure ring 53, and the shaft members 47 and 49 are fitted to the respective pinion gears 9.

  When the two shaft members 47, 49 can be inserted into the respective engagement holes 65, the two shaft members 47, 49 are moved in parallel to engage the centering recesses 47a, 49a in the length direction so as to form a cross pinion. A shaft 45 is configured.

  The engagement hole 65 is not limited to a long hole, and the pressure ring 53 is formed of two members or the like separately with the pinion shaft 45 interposed therebetween, and a U-shaped recess provided in the opposing portion of the pressure ring of the two members. Can also be formed. In this case, the pinion shaft formed as an integral spider as described above can be incorporated.

In the assembled state, a spherical portion 67 is provided on the inner surface of the central portion of the pressure ring 53 to support the back surface of the pinion gear 9. Each tip portion of the cross pinion shaft 45 with which the pinion gear 9 is fitted is engaged with each engagement hole 65 of the pressure ring 53.

  On both sides of the pressure ring 53, recesses 69 and 71 for the friction clutches 55 and 57 are formed. In the recesses 69 and 71, pressing surfaces 69a and 71a are formed. Engaging grooves 69b and 71b are formed on the outer peripheral portions of the recesses 69 and 71, respectively. The engagement groove 71b on the cam ring 51 side is formed longer than the engagement groove 69b on the opposite side.

  The friction clutches 55 and 57 are accommodated in the recesses 69 and 71. The friction clutch 55 is interposed between the fastening receiving surface 17a and the pressing surface 69a, and the friction clutch 57 is interposed between the pressing surfaces 62 and 71a.

  The inner plate of the friction clutch 55 is engaged with the engaging portion 43 of the side gear 5 in the rotational direction so as to be movable in the axial direction, and the outer plate is engaged with the engaging groove 69b of the pressure ring 53 in the rotational direction so as to be movable in the axial direction. Is engaged.

  The inner plate of the friction clutch 57 is engaged with the engaging portion 44 of the side gear 7 in the rotational direction so as to be axially movable. The outer plate is engaged with the engaging groove 71b of the pressure ring 53 in the rotational direction so as to be axially movable. Is engaged. An engaging protrusion 51a of the cam ring 51 is engaged with the end of the engaging groove 71b.

  The friction clutches 55 and 57 only need to be differentially limited, and can be configured to be arranged only on one side. Further, the friction member is not limited to a multi-plate friction plate, and may be formed of a cone clutch or the like.

[Action]
In the differential device 1, the bearing support portions 19a and 23a of the differential case 3 are rotatably supported by the housing of the torque transmission device via a bearing, and are attached to a flange portion including the main body flange portion 15 and the lid flange portion 21. The ring gear meshes with the drive pinion gear.

  When drive torque is input from the drive pinion gear through the ring gear, the differential case 3 rotates. As the differential case 3 rotates, drive torque is transmitted to the cam ring 51 that engages with the lid 13, and torque is transmitted from the cam ring 51 to the pinion shaft 45 via the pressure ring 53. By this torque transmission, the pinion gear 9 and the side gears 5 and 7 are rotated together with the differential case 3. Torque is transmitted from the side gears 5 and 7 via the left and right axle shafts, and the left and right wheels are rotationally driven.

  When the cam surface 25a comes into contact with the cam protrusion 61 of the cam ring 51 in the rotational direction during transmission of the drive torque, a thrust force is generated by the cam action between the cam surface 25a and the cam follower surface 61a, and the cam ring 51 is moved to the pressure ring 53. Move to the side.

  Due to the movement of the cam ring 51, the engaging protrusion 51a moves relative to the engaging groove 71b, the friction clutch 57 is fastened between the cam ring 51 and the pressure ring 53, the fastening force is transmitted to the pressure ring 53, and the friction is caused. The clutch 55 is fastened between the pressure ring 53 and the main body end wall portion 17.

  In this case, movement of the cam ring 51 and the pressure ring 53 in the axial direction is allowed by the gaps between the respective parts.

  As the torque transmitted from the differential case 3 to the cam ring 51 increases, the cam force between the cam surface 25a and the cam follower surface 61a increases, so the friction clutches 55 and 57 increase the fastening force according to the drive torque. The side gears 5 and 7 and the differential case 3 are frictionally engaged by the fastening force of the friction clutches 55 and 57, and differential restriction between the side gears 5 and 7 is performed. As described above, the differential limiting force increases as the torque increases.

  Torque is transmitted to the left and right wheels while performing differential restriction in accordance with torque increase.

  Further, since the preload is applied to the friction clutches 55 and 57 via the cam ring 51 and the pressure ring 53 by the biasing force of the coil spring 63, torque transmission can be performed while obtaining a differential limiting force from the beginning of driving. .

  At the time of differential rotation of the left and right wheels, the pinion gear 9 rotates around the pinion shaft 45, and differential rotation between the side gears 5 and 7 can be allowed. The cam rotation of the cam ring 51 is allowed by the differential rotation. 61 is pressed against the cam surface 25a and differentially limited by a frictional force according to differential rotation, so that differential locking can be performed.

  Therefore, stable cornering traveling or the like is possible.

  When coasting torque is input to the side gears 5 and 7 from the left and right wheels via the axles, the cam force between the cam surface 25a and the cam follower surface 61a acts on the opposite surface to that during driving.

  For this reason, the differential limitation at the time of the coasting torque can be limited by the frictional force according to the preload and the coasting torque of the friction clutches 55 and 57.

  In this case, the torque is output from the differential case 3.

[Effect of Example]
The differential case 3 of the differential device 1 according to the embodiment of the present invention includes a main body portion 11 and a lid body portion 13 that closes an end portion of the main body portion 11. The pressing member includes a cam ring 51 that engages with the lid body portion 13. A pressure ring 53 that engages with the pinion shaft 45, and the cam ring 51 includes a cam mechanism between the cam body 51 and the lid 13, and is engaged with the pressure ring 53 in the rotational direction so as to be relatively movable in the axial direction. The mechanism causes the cam ring 51 to engage with the lid body portion 13 in the rotational direction and causes the cam ring 51 to generate a thrust force on the lid body portion 13 by the relative rotation of the cam ring 51 with respect to the lid body portion 13 to be fastened. Give power.

  For this reason, the friction clutches 55 and 57 can be fastened by the preload by the coil spring 63, drive torque, etc., and a differential restriction | limiting can be performed.

  Moreover, by changing the cam ring 51, the relationship with the cam surface 25a can be changed, the characteristics of the cam mechanism can be changed, and the lock rate of the differential rotation can be easily changed.

  That is, by changing the cam ring 51 and changing the inclination of the cam follower surface 61a, the contact form of the cam follower surface 61a with the cam surface 25a changes, and the lock rate can be changed.

  Therefore, the differential limiting characteristic can be changed by a simple operation of simply removing the lid portion 13 and replacing the cam ring 51, and the convenience of the user can be greatly improved even in automobile competitions.

  The cam surface 25a is not provided with a special member interposed between the lid body portion 13 and the cam ring 51, but is formed in the lid body portion 13, so that the space in the axial direction is omitted and the size reduction is achieved. This is possible, and the number of parts and parts management can also be reduced.

  Since the coil spring 63 is disposed on the lid portion 13, the coil spring 63 can be easily replaced, and the preload can be easily changed. The coil spring 63 can be removed to eliminate the preload.

  Since the coil spring 63 is housed in the spring recess 31 formed in the lid portion 13, the axial space can be omitted at this point, and the size can be reduced, and the number of parts and part management can also be reduced. .

DESCRIPTION OF SYMBOLS 1 Differential apparatus 3 Differential case 5, 7 Side gear 9 Pinion gear 11 Differential case main body 13 Differential case cover body 25 Hole 25a Cam surface (cam mechanism)
45 Pinion shaft 51 Cam ring (pressing member)
53 Pressure ring (pressing member)
55, 57 Friction clutch (friction member)
61 Cam protrusion (cam mechanism)
63 Coil spring (biasing member)

Claims (4)

The differential case and the pinion shaft engage with each other, and the rotation of the differential case allows the transmission of torque as the pinion gear revolves. A differential device including a pressing member that applies a fastening force to a friction member for limiting the fastening force according to the fastening force,
The differential case includes a main body portion and a lid portion that closes an end portion of the main body portion,
The pressing member includes a first pressing member that engages with the lid body portion and a second pressing member that engages with the pinion shaft,
The first pressing member includes a cam mechanism between the first pressing member and the second pressing member and is engaged with the second pressing member in the rotational direction so as to be relatively movable in the axial direction.
The cam mechanism causes the engagement of the first pressing member with the lid body portion in the rotation direction and the first rotation of the first pressing member with respect to the lid body portion in the rotation direction. Generating a thrust force against the lid portion on the pressing member to give the fastening force;
A differential device characterized by that. The differential device according to claim 1,
The cam mechanism includes a cam surface formed in a hole portion formed in the lid body portion and a cam protrusion formed on the first pressing member and fitted into the hole portion to perform the engagement with the cam surface. With parts,
A differential device characterized by that. A differential device according to claim 2, wherein
The cam surface is formed of a curved surface,
A differential device characterized by that. The differential device according to any one of claims 1 to 3,
An urging member that urges the first pressing member toward the second pressing member is provided between the first pressing member and the lid portion.
A differential device characterized by that.

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