JP4145817B2 - Differential unit with differential limiting mechanism - Google Patents

Description

  The present invention relates to a differential limiter including a differential mechanism that distributes and outputs a driving force of a prime mover input to a differential case to two output shafts, and a friction clutch that limits differential rotation between the two output shafts. The present invention relates to a mechanism-equipped differential device, and more particularly to an actuator provided with an actuator that generates a fastening force for fastening a friction clutch, on the axis of an output shaft and outside a differential case.

  In order to limit the function of the differential mechanism that distributes the driving force to the left and right wheels of the automobile, an actuator for fastening a friction clutch for limiting the differential provided in the differential case is placed on the half shaft that extends outward from the differential case. A differential device with a differential limiting mechanism, which is arranged and moves the half shaft in the axial direction by the fastening force generated by the actuator to fasten the friction clutch, has already been proposed by Japanese Patent Application No. 2002-275128, filed by the present applicant. Has been. According to this differential device with a differential limiting mechanism, the actuator can be externally attached to the differential case. This can contribute to cost reduction by reducing the design change applied to the existing differential mechanism.

  However, the one proposed in the above Japanese Patent Application No. 2002-275128 combines the function of transmitting the driving force of the internal combustion engine to the driving wheel to the half shaft and the function of transmitting the fastening force generated by the actuator to the friction clutch. There are the following problems.

  In other words, when the driving force of the internal combustion engine is transmitted to the drive wheels, if the friction shaft is engaged by moving the half shaft in the axial direction by the actuator, the side gear and the half of the differential mechanism are driven by the driving force of the internal combustion engine. Since a large load is applied to the spline coupling portion with the shaft, the fastening force generated by the actuator is reduced by the frictional force caused by the load, and there is a problem that a large and high output actuator is required. In addition, since the frictional force changes according to the magnitude of the driving force of the internal combustion engine, the fastening force transmitted from the actuator to the friction clutch changes, and the differential limit generated in the differential mechanism due to the engagement of the friction clutch. There was a problem that the magnitude of torque became unstable.

  The present invention has been made in view of the above-described circumstances so that the friction clutch of the differential mechanism disposed inside the differential case can be stably engaged with the fastening force generated by the actuator disposed outside the differential case. The purpose is to do.

In order to achieve the above object, according to the first aspect of the present invention, a differential mechanism that distributes and outputs the driving force of the prime mover input to the differential case to the two output shafts, and the two output shafts A differential device with a differential limiting mechanism including a friction clutch for limiting differential rotation between the actuator and the differential case, the actuator for generating a fastening force for fastening the friction clutch on the axis of the output shaft A hollow shaft extending from the actuator to the inside of the differential case is provided on the outer periphery of the output shaft, and the fastening force generated by the actuator is transmitted to the friction clutch via the hollow shaft. A diameter-enlarged portion that is expanded inside is provided, and an extension portion that extends through the enlarged-diameter portion to the side gear side of the differential mechanism is defined as a differential. Formed in down Shall case, the differential limiting mechanism with a differential apparatus characterized by supporting the thrust force of the side gears in the extending portion is proposed.

  The half shaft 11 and the left axle 13 of the embodiment correspond to the output shaft of the present invention, and the first to third hollow shafts 47 to 49 of the embodiment correspond to the hollow shaft of the present invention, and the internal combustion engine of the embodiment. E corresponds to the prime mover of the present invention.

  According to the configuration of the first aspect, the friction force clutch of the differential mechanism provided inside the differential case is provided with the fastening force generated by the actuator provided outside the differential case on the outer periphery of the output shaft. Since the driving force of the engine is transmitted through a hollow shaft that does not transmit, the fastening force of the actuator can be transmitted to the friction clutch without being reduced by the friction force generated by the driving force, and the friction clutch can be fastened stably.

Also especially hollow shaft, provided with enlarged diameter portion which has a larger diameter in the differential case, extension portion extending from the differential case to the side gears side, so to support the thrust force of the side gears through said enlarged diameter portion Thus, the thrust force of the side gear is transmitted to the hollow shaft and the fastening force of the friction clutch generated by the actuator is prevented from being canceled, and the friction clutch can be fastened with high accuracy by the fastening force generated by the actuator.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings.

  1 to 8 show an embodiment of the present invention. FIG. 1 is a rear view of an internal combustion engine for an automobile, FIG. 2 is an enlarged sectional view of a differential mechanism and an actuator, and FIG. 2 is an enlarged view of part 4 of FIG. 3 showing the structure of the actuator, FIG. 5 is an enlarged view of part 5 of FIG. 3 showing the structure of the friction clutch, and FIG. 6 is a sectional view taken along the line 7-7 in FIG. 3, and FIG. 8 is a sectional view taken along the line 8-8 in FIG.

  As shown in FIG. 1, an internal combustion engine E mounted horizontally on the front body of a front engine / front drive automobile has a transmission T integrally coupled to a left side surface thereof, and a difference between the rear surface of the transmission T and the rear surface thereof. A moving mechanism D is provided. A half shaft 11 (intermediate shaft) extends rightward from a differential mechanism D arranged to be shifted leftward from the vehicle body center line, and a right axle that drives a right drive wheel (not shown) to the halfshaft 11. 12 is connected, and a left drive wheel (not shown) is driven via a left axle 13 extending in the left direction from the differential mechanism D. The right end of the half shaft 11 is supported by a stay 10 fixed to the engine block 22.

  As is clear from FIG. 2, the housing 14 that houses the differential mechanism D covers the housing body 15 that is formed integrally with the casing of the transmission T and the left end opening of the housing body 15. And a cover plate 17 fixed by a plurality of bolts 16. A plurality of actuators A, which are separately attached to the right side of the differential mechanism D, are an actuator case 18 that fits into the right end opening of the housing body 15 of the differential mechanism D, and a plurality of actuators A so as to cover the right end opening of the actuator case 18. The actuator cover 20 is fixed by a plurality of bolts 19... And is fixed to the engine block 22 by a plurality of bolts 21 penetrating the actuator case 18. The differential mechanism D and the actuator A constitute a differential device.

  The differential mechanism D housed in the housing 14 includes a first case 24 on the right side supported by the roller body 23 on the housing body 15 and a second case 26 on the left side supported by the roller bearing 25 on the cover plate 17. Are connected by a plurality of bolts 27, and an axle drive gear 29 driven by the transmission T is fixed to the outer periphery of the first case 24 by a plurality of bolts 30.

  Next, the structure of the differential mechanism D will be described with reference to FIGS. 3 and 5 to 7.

  The differential mechanism D housed in the housing 14 includes four pinion shafts 31 integrated so as to intersect in a cross shape. The pinion shafts 31 having a circular cross section are formed with chamfers 31a at their ends, and the chamfers 31a are fitted into four support grooves 24a formed on the inner peripheral surface of the first case 24. To do. Four pinions 32 are rotatably supported on the four pinion shafts 31. Spacers 33 are arranged between the pinions 32 and the inner peripheral surface of the first case 24, and the radial positions of the pinions 32 are regulated by these spacers 33.

The outer periphery of the half shaft 11 inserted into the first case 24 is splined to the right side gear 34 </ b> R and is prevented from coming off by a snap ring 35. Further, the right end of the left axle 13 inserted through the second case 26 and inserted into the first case 24 is splined to the clutch inner 37 and is prevented from coming off by a snap ring 38. Side gears 34 L of the left side is formed integrally with the right side surface of the clutch inner 37. The left and right side gears 34L and 34R mesh with the four pinions 32.

  A clutch outer 40 is integrally formed on the inner periphery of the first case 24 so as to face the outer periphery of the clutch inner 37, and a plurality of clutch plates 41 (five in the embodiment) are provided on the inner peripheral surface of the clutch outer 40. The outer peripheral portions of the clutch inners 37 are spline-fitted, and the inner peripheral portions of a plurality of (six in the embodiment) clutch disks 42 are spline-fitted to the outer peripheral surface of the clutch inner 37. The clutch plates 41 and the clutch disks 42 are alternately arranged so that the friction materials 43 attached to both surfaces of the clutch disks 42 contact the clutch plates 41.

  The outer peripheral portion of the pressure plate 44 is spline-fitted to the inner peripheral surface of the clutch outer 40, and the left side surface of the pressure plate 44 is opposed to the right side surface of the clutch disk 42 located at the rightmost end. A plurality (four in the embodiment) of lever lever storage recesses 24b extending in the radial direction are formed on the inner surface of the first case 24 facing the right side surface of the pressure plate 44, and each lever lever storage recess 24b A fulcrum 45a at the radially outer end of the lever lever 45 is slidably engaged with the radially outer end.

  Inside the actuator case 18, the first hollow shaft 47 is fitted to the outer periphery of the half shaft 11 via a needle bearing 46 (see FIG. 1) so as to be relatively rotatable and axially movable. Inside the first case 24, the right end of the second hollow shaft 48 is engaged with the left end of the first hollow shaft 47 so that the right end of the second hollow shaft 48 is not rotatable relative to the left end, and the right end of the third hollow shaft 49 is connected to the left end of the second hollow shaft 48. Engages with concaves and convexes so that relative rotation is impossible. A diameter-expanded portion 48a having a diameter increased along the inner peripheral surface of the first case 24 is formed on the left end side of the second hollow shaft 48, and the diameter of the third hollow shaft 49 is set to the maximum diameter of the diameter-expanded portion 48a. Match.

  A plurality (six in the embodiment) of through holes 48b are formed in the enlarged diameter portion 48a of the second hollow shaft 48, and the four extended portions 24c projecting from the inner surface of the first case 24 are through holes. It loosely penetrates 48b and protrudes inside the enlarged diameter portion 48a. The tip of each extending portion 24c comes into contact with the back surface of the right side gear 34R via the friction washer 50. The back surface of the left side gear 34 </ b> L, that is, the left side surface of the clutch inner 37 abuts against the inner surface of the second case 26 via the friction washer 51.

  The third hollow shaft 49 is formed with four U-shaped notches 49a that open to the left end side at 90 ° intervals. The third hollow shaft 49 can move in the axial direction while avoiding interference between the four pinion shafts 31 and the spacers 33 fitted to the outer periphery thereof by the notches 49a. And the press part 49b which presses the power point 45b provided in the radial direction inner end of the lever lever 45 is formed in the left end of the 3rd hollow shaft 49. As shown in FIG. An action point 45 c that abuts against the right side surface of the pressure plate 44 is provided at an intermediate portion of the lever lever 45.

  Thus, the clutch inner 37, the clutch outer 40, the clutch plate 41, the clutch disk 42, the pressure plate 44, and the lever lever 45, constitute a friction clutch 52 for fastening the left axle 13 to the differential case 28. Is done.

  Next, the structure of the actuator A that fastens the friction clutch 52 via the first to third hollow shafts 47, 48, and 49 will be described with reference to FIGS.

  A first flange member 61 is slidably fitted to the right end of the first hollow shaft 47 extending inside the actuator case 18 and the actuator cover 20, and the spring seat 63 is secured to the first hollow shaft 47 by a clip 62. The coil spring 64 is disposed in a compressed state between the first flange member 61 and the back surface of the first flange member 61. A second flange member 65 is slidably fitted on the right half shaft 11 of the first flange member 61, and a load cell 66 is provided between the back surface of the second flange member 65 and the inner surface of the actuator cover 20. It is done.

  On the half shaft 11 between the first flange member 61 and the second flange member 65, the first cam plate 67 and the second cam plate 68 are rotatable via needle bearings 69 and 70, respectively, and are movable in the axial direction. Supported. The first cam plate 67 contacts the first flange member 61 via the thrust bearing 85, and the second cam plate 68 contacts the second flange member 65 via the thrust bearing 86. Inclined cam grooves 67a..., 68a... Are formed on the opposing surfaces of the first and second cam plates 67 and 68, and the balls 71 are accommodated in the cam grooves 67a. The first and second cam plates 67 and 68 and the balls 71 constitute a ball cam mechanism 72.

  A first shaft 73 is supported on the actuator case 18 via a ball bearing 74 and a needle bearing 75, and a second shaft 76 is supported via ball bearings 77 and 78. The first gear 80 provided on the first shaft 71 connected in series to the output shaft 79 a of the motor 79 supported on the actuator case 18 is connected to the second and third gears 81 and 82 provided on the second shaft 76. It meshes with the second gear 81. In addition, fourth and fifth gears 83 and 84 are formed on the outer circumferences of the first and second cam plates 67 and 68, respectively. The fourth gear 83 meshes with the second gear 81 of the second shaft 76, and The fifth gear 84 meshes with the third gear 82 of the second shaft 76. The gear ratio between the second gear 81 and the fourth gear 83 and the gear ratio between the third gear 82 and the fifth gear 84 are slightly different.

  The functions of the spring seat 63 and the coil spring 64 in FIG. 4 are as follows.

  The actuator case 18, the actuator cover 20, the ball cam mechanism 72, the motor 79, the half shaft 11, the first hollow shaft 47 and the like are assembled in advance as a subassembly, and then the actuator case 18 is coupled to the housing body 15 of the differential mechanism D. Is done. In a state before the actuator case 18 of the subassembly is coupled to the housing body 15 of the differential mechanism D, the first hollow shaft 47 can be moved to the left side so as to come out of the actuator case 18, so that the first cam of the ball cam mechanism 72 There is a possibility that the plate 71 and the second cam plate 68 open and the balls 71... Fall off from the cam grooves 67 a.

  However, in this embodiment, the coil spring 64 is disposed between the spring seat 63 and the first flange member 61 that are locked to the right end of the first hollow shaft 47 by the clip 62, so that as shown by the chain line in FIG. When the spring seat 63 is in contact with the step on the inner surface of the actuator case 18, the first flange member 61 is urged to the right by the coil spring 64, so that the ball cam mechanism 72 is held in the assembled state and the ball 71 It is possible to prevent omission of…. When the actuator case 18 is coupled to the housing body 15 and the first hollow shaft 47 is coupled to the second hollow shaft 48, the first hollow shaft 47 moves from the chain line position in FIG. 4 to the solid line position.

  Next, the operation of the embodiment of the present invention having the above configuration will be described.

  The differential mechanism D exhibits a differential limiting function in addition to the normal differential function, and the differential limiting torque generated by the differential limiting function is generated by the operation of the actuator A.

  First, the normal differential function of the differential mechanism D will be described.

  When the driving force of the internal combustion engine E is input to the axle drive gear 29 of the differential mechanism D via the transmission T, the differential case 28 coupled to the axle drive gear 29 with bolts 30. When the vehicle is in a straight traveling state, the four pinions 32 are not rotated with respect to the pinion shafts 31 and are not rotated with respect to the pinions 32, but the left side gear 34L meshed with the pinions 32 and the right axle meshed with the left axle 13 and the pinions 32. The side gear 34R and the integral half shaft 11 rotate at the same speed, and the driving force is evenly distributed to the left and right driving wheels.

  For example, when the vehicle is in a left turn state, the left axle 13 connected to the left drive wheel is decelerated and the half shaft 11 connected to the right drive wheel is accelerated, so that a differential rotation occurs between the left and right side gears 34L and 34R. Although generated, the differential rotation is absorbed by the rotation of the pinions 32 meshed with the left and right side gears 34L, 34R. Similarly, when the vehicle is in a right turn state, the left axle 13 connected to the left drive wheel is accelerated and the half shaft 11 connected to the right drive wheel is decelerated, so that the difference between the left and right side gears 34L and 34R. Although rotation occurs, the differential rotation is absorbed by the rotation of the pinions 32 meshed with the left and right side gears 34L, 34R.

  Next, the differential limiting function generated by the operation of the actuator A will be described.

  When the motor 79 of the actuator A is driven, the rotation of the first gear 80 of the first shaft 73 coupled to the output shaft 79a is transmitted to the second gear 81 and the second shaft 76 rotates. When the second shaft 76 rotates, the first cam plate 67 rotates through the second gear 81 and the fourth gear 83, and the second cam plate 68 rotates through the third gear 82 and the fifth gear 84. However, since the gear ratio between the second gear 81 and the fourth gear 83 and the gear ratio between the third gear 82 and the fifth gear 84 are slightly different, the first and second cam plates of the ball cam mechanism 72 are different. 67 and 68 rotate relative to each other. As a result, the relative positions of the cam grooves 67a of the first and second cam plates 67, 68 change from the state shown in FIG. 8A to the state shown in FIG. 1. The second cam plates 67 and 68 are driven in directions away from each other.

  The second cam plate 68 that has received a rightward load generated by the ball cam mechanism 72 is prevented from moving rightward by the actuator cover 20. Accordingly, the first cam plate 67 that has received the leftward load generated by the ball cam mechanism 72, that is, the fastening force that fastens the friction clutch 52, moves to the left, and the first cam plate 67 passes through the thrust bearing 85 and the first flange member 61. The hollow shaft 47 is pressed leftward. At this time, the engaging force of the friction clutch 52 generated by the ball cam mechanism 72 is detected by the load cell 66, and the output of the motor 79 is feedback-controlled so that the engaging force matches a predetermined value.

  When a leftward fastening force is applied to the first hollow shaft 47 by the actuator A, the second hollow shaft 48 and the third hollow shaft 49 coupled to the first hollow shaft 47 move to the left, and the third hollow shaft 49 The pressing portions 49b provided at the left end press the force points 45b of the four lever levers 45. As a result, the lever levers 45 swing around the fulcrum 45a, and the action point 45c presses the pressure plate 44 to the left, so that the clutch plates 41 and the clutch disks 42 are in close contact with each other, and the clutch The inner 37 and the clutch outer 40 are coupled together.

  Since the distance L1 between the fulcrum 45a and the force point 45b of the lever lever 45 is set larger than the distance L2 between the fulcrum 45a and the action point 45c, the fastening force F1 input to the lever lever 45 is multiplied by L1 / L2. The pressure plate 44 can be pressed with the boosted fastening force F2, and thus a sufficient fastening force can be applied to the friction clutch 52 even if the motor 79 of the actuator A is downsized.

  When the friction clutch 52 is fastened in this way, the left axle 13 integrated with the clutch inner 37 is integrated with the differential case 28, so that the left axle 13 and the half shaft 11, that is, the left axle 13 and the right axle are integrated. The axle 12 is integrated so as not to rotate relative to each other, and the operation function of the differential mechanism D is limited, so that it is possible to escape from soft ground such as muddyness, and stability during high-speed straight running can be improved. . At this time, the current that drives the motor 79 is controlled to change the fastening force generated by the actuator A, thereby causing the friction clutch 52 to generate a predetermined slip, thereby allowing the differential mechanism D to have a differential limit of an arbitrary magnitude. Torque can be demonstrated.

  As described above, the fastening force of the friction clutch 52 generated by the actuator A can be axially moved to the outer periphery of the half shaft 11 without relative to the half shaft 11 to which the driving force of the internal combustion engine E is transmitted, and can be relatively rotated. Since it transmits via the 1st-3rd hollow shafts 47, 48, and 49 arrange | positioned possible, the actuator A is the frictional force which acts on the spline coupling part of the half shaft 11 by transmitting the driving force of the internal combustion engine E. Therefore, the frictional force of the friction clutch 52 can be fastened stably.

  The first to third hollow shafts 47, 48, 49 rotate together with the differential case 28. Since the rotation is idle without transmission of the driving force of the internal combustion engine E, a large frictional force is generated during the axial movement. Will not occur.

  By the way, when the differential mechanism D operates, axial thrust force acts on the left and right side gears 34L, 34R meshing with the pinions 32. At this time, if the thrust force of the right side gear 34R is supported by the inner surface of the enlarged diameter portion 48a of the second hollow shaft 48, there is a problem that the fastening force generated by the actuator A is reduced by the thrust force. However, in this embodiment, since the thrust force of the right side gear 34R is received by the extending portion 24c of the first case 24 of the operating mechanism D, the thrust force is transmitted to the second hollow shaft 48. The above problem can be solved by preventing.

  Since the friction washer 50 is disposed between the right side gear 24R and the first case 24 and the friction washer 51 is disposed between the left side gear 34L and the second case 26, the friction washer 51 acts on both the side gears 34R and 34L. A frictional force is generated between the first and second cases 24 and 26 by the thrust force. As described above, by generating the predetermined operation limiting torque by the frictional force generated by the thrust force acting on the both side gears 34R and 34L without the engagement of the friction clutch 52, the straight running stability of the vehicle can be improved. .

  As mentioned above, although the Example of this invention was explained in full detail, this invention can perform a various design change in the range which does not deviate from the summary.

  For example, the actuator A is not limited to an electric type, and a hydraulic actuator may be employed.

  In the embodiment, the hollow shaft is divided into the first to third hollow shafts 47, 48, and 49, and the second hollow shaft 48 is provided with the enlarged diameter portion 48a. However, the division method is arbitrary.

Rear view of automotive internal combustion engine Enlarged sectional view of differential mechanism and actuator 2 is an enlarged view of part 3 of FIG. 2 showing the structure of the differential mechanism. 4 is an enlarged view of part 4 in FIG. 3 showing the structure of the actuator. FIG. 3 is an enlarged view of part 5 showing the structure of the friction clutch. 6-6 sectional view of FIG. Sectional view along line 7-7 in FIG. Sectional view taken along line 8-8 in FIG.

Explanation of symbols

11 Half shaft (output shaft)
13 Left axle (output shaft)
24c Extension part 28 Differential case 34R Side gear 47 1st hollow shaft (hollow shaft)
48 Second hollow shaft (hollow shaft)
48a Enlarged portion 49 Third hollow shaft (hollow shaft)
52 Friction clutch A Actuator D Differential mechanism E Internal combustion engine (prime mover)

Claims (1)

Between the differential mechanism (D) that distributes and outputs the driving force of the prime mover (E) input to the differential case (28) to the two output shafts (11, 13), and the two output shafts (11, 13) A differential device with a differential limiting mechanism including a friction clutch (52) for limiting the differential rotation of the actuator, wherein the actuator (A) for generating a fastening force for fastening the friction clutch (52) is connected to the output shaft (11). , a on the axis 13), and provided outside of the differential case (28), the output shaft (11, 13) a hollow shaft extending from the actuator (a) to the outer periphery in the interior of the differential case (28) of (47, 48, 49) for transmitting the fastening force generated by the actuator (A) to the friction clutch (52) via the hollow shaft (47, 48, 49) .
The hollow shaft (47, 48, 49) is provided with an enlarged diameter portion (48a) having an enlarged diameter in the differential case (28), and the side gear of the differential mechanism (D) passes through the enlarged diameter portion (48a). (34R) An extension portion (24c) extending to the side is formed in the differential case (28), and the thrust force of the side gear (34R) is supported by the extension portion (24c). Differential device with limiting mechanism .

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