JP2016142369A - Power force disconnecting mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power force disconnecting mechanism simplifying and restricting an increased cost of a mechanism related to a driving mode changing-over operation between a two-wheel driving mode and a four-wheel driving mode at a part-time type four-wheel driving vehicle and provide a four-wheel driving system utilizing the power force disconnecting mechanism.SOLUTION: Each of a pilot cam 55 and a main cam 56 having a first ball 57 and a second ball 58 held therebetween is arranged along the inside in a radial direction at a cam plate 53 fixed to a first shaft 51. The pilot cam 55 is spline connected to a friction plate 62 ground connected to a first case 59 and at the same time the pilot cam is biased from both sides with a first spring SP1 and a second spring SP2 and in turn the main cam 56 is engaged with a clutch drum 61 at an extremity end thereof and at the same time rotatably attached to the first shaft 51. A connecting surface between the pilot cam 55 and the main cam 56 is provided with a step D descending in an axial left side direction and the opposite side of the pilot cam 55 of the clutch drum 61 is biased by a third spring SP3.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a power cutting mechanism, and more specifically, a power that simplifies a mechanism relating to driving mode switching between a two-wheel driving mode and a four-wheel driving mode in a so-called part-time four-wheel drive vehicle and suppresses cost increase. The present invention relates to a cutting mechanism and a four-wheel drive system using the cutting mechanism.

  A so-called part-time four-wheel drive system is known that is configured to transmit the driving force from the engine only to the front wheels, and to transmit the driving force to the rear wheels according to the road surface conditions (for example, patents). See reference 1.) In such a four-wheel drive system, a first connecting / disconnecting mechanism for intermittently transmitting (turning on / off) the power is provided between the front wheel differential (front differential) and the front and rear wheel connecting shaft (propeller shaft). And a coupling device for changing a distribution ratio of power transmitted to the rear wheel between 0% and 50% between the front and rear wheel connecting shaft (propeller shaft) and the rear wheel differential (rear differential). In addition, a second connecting / disconnecting mechanism for interrupting (turning on / off) the transmission of power between the rear wheel differential (rear differential) and the left or right rear wheel is provided. The first connecting / disconnecting mechanism, the second connecting / disconnecting mechanism, and the coupling device are all configured by an electronically controlled power transmission mechanism that is driven by a control signal from an engine control unit (ECU). That is, in the two-wheel drive mode, the first connecting / disconnecting mechanism and the second connecting / disconnecting mechanism are all disconnected by a control signal from the engine control unit (ECU), and the power from the engine is transmitted only to the left and right front wheels via the front differential. Each is transmitted. Here, the second connecting / disconnecting mechanism is cut off because the rotational force of the left and right rear wheels rotates the propeller shaft via the rear differential, and the rotation of the propeller shaft or the like in which part of the energy of the fuel does not contribute to traveling. This is to prevent the fuel consumption rate from deteriorating. On the other hand, in the four-wheel drive mode, the first connecting / disconnecting mechanism, the second connecting / disconnecting mechanism, and the coupling device are all connected by a control signal from the engine control unit (ECU), and the power from the engine is transmitted via the front differential. The power transmitted to the left and right front wheels and the propeller shaft is transmitted to the left and right rear wheels via the rear differential.

  By the way, in a part-time four-wheel drive system, there is known a power cutting mechanism using a ball cam mechanism that interrupts (on / off) transmission of power from the front wheel to the rear wheel (see, for example, Patent Document 2). In this power cutting mechanism, a ball cam mechanism comprising an annular first cam member and an annular second cam member and a ball sandwiched therebetween is moved to the left in the axial direction by a hydraulic clutch piston (input shaft The clutch plate of the clutch drum on the side and the clutch plate of the clutch hub (on the output shaft side) are pressed. When both clutch plates are pressed, power is transmitted, whereby the second cam member begins to rotate. As a result, differential rotation occurs between the first cam member and the second member, thereby causing the ball to move. When a cradle rides from a recess (deep place) to a surface (shallow place), a cam force is generated. Due to this cam force, the second cam member is further moved to the left in the axial direction, and both clutch plates are further pressed and completely engaged at the end. As a result, the input shaft and the output shaft are connected, thereby transmitting power from the input shaft to the output shaft.

JP 2011-79421 A Japanese Patent No. 4271001

In the four-wheel drive system described in Patent Document 1, the first connecting / disconnecting mechanism, the second connecting / disconnecting mechanism, and the coupling device are all controlled by a control signal from an engine control unit (ECU). Therefore, an electronic device such as an actuator for driving these mechanisms, a drive source (hydraulic pressure, power source) for controlling the actuators, and a sensor is required. This increases control complexity and manufacturing costs.
Further, in the power cutting mechanism using the ball cam mechanism, a hydraulic mechanism related to the hydraulic clutch piston is required to move the ball cam mechanism in the axial direction. Therefore, a separate hydraulic circuit for supplying hydraulic pressure to the hydraulic mechanism is also necessary. The hydraulic circuit is composed of an oil passage, an oil pump, an electric motor for driving the oil pump, a spool valve, an electromagnetic valve for driving the spool valve, and the like, and control of these electric actuators is performed by a control unit such as an ECU. . Therefore, even when the power cutting mechanism using the ball cam mechanism is applied to a four-wheel drive system, the control is complicated and the manufacturing cost is increased.
Therefore, the present invention has been made in view of the above-described problems of the prior art, and its object is to switch a drive mode between a two-wheel drive mode and a four-wheel drive mode in a part-time four-wheel drive vehicle. It is an object of the present invention to provide a power cutting mechanism that simplifies the mechanism and suppresses the cost, and a four-wheel drive system using the same.

In the power cutting mechanism of the present invention for achieving the above object, the first shaft (51) and the second shaft (52) divided on the same axis are provided orthogonal to the first shaft (51). A first cam plate (53); a second cam plate (55) provided facing the first cam plate (53); and the second cam plate facing the first cam plate (53) A third cam plate (56) provided adjacent to the inner side in the radial direction of (55), and a first ball sandwiched between the first cam plate (53) and the second cam plate (55) (57), a second ball (58) sandwiched between the first cam plate (53) and the third cam plate (58), and an axial movement with respect to the second shaft (52) Power cutting with clutch drum (61) synchronized with rotation direction A structure,
The second cam plate (55) is configured to be non-rotatable and axially movable by the fixing means (62), and is urged to the right in the axial direction by the elastic body (SP2) and presses the clutch drum (61). Part (B5),
The third cam plates (56) are freely mounted on the first shaft (51) and are arranged alternately on the clutch plates (CP2) of the clutch drum (61). (CP1) and an engaging portion (D) that engages with the second cam plate (55) in the axial direction,
The clutch drum (61) is biased to the right in the axial direction by an elastic body (SP3).

In the above configuration, the third cam plate (56) corresponding to the conventional clutch hub is attached to the first shaft (51) in a free state, and the clutch between the clutch drum (61) and the third cam plate (56). The fastening is achieved by the cam force (Fm) generated due to the differential rotation between the third cam plate (56) and the first cam plate (53). The connection with (51) is made through the second ball (58). On the other hand, in order to generate the cam force (Fm), the second cam plate (55) is axially driven by the cam force (Fp) generated due to the differential rotation with the first cam plate (53). The clutch drum (61) is pressed to such an extent that the driving force from the second shaft (52) is applied to the third cam plate (56) by being moved to the left side, and the clutch plate (CP2) of the clutch drum (61). A pilot function for fastening the clutch plate (CP1) of the third cam plate (56) is performed. That is, when the first shaft (51) rotates, a cam force (Fp) is generated between the second cam plate (55) and the first cam plate (53). Due to this cam force (Fp), the second cam plate (55) moves to the left in the axial direction and presses the clutch drum (61). As a result, the clutch plates (CP1, CP2) are in a semi-engaged state, the third cam plate (56) is rotationally driven by the driving force from the second shaft (52), and a new cam force (Fm) is generated between the cam plates. The third cam plate (56) begins to move to the left in the axial direction due to this cam force (Fm). This movement further moves the second cam plate (55) to the left in the axial direction to further press the clutch drum (61). Thereafter, the fixing means (62) is separated from the inner peripheral surface of the case, so that the second cam plate (55) is freely rotatable, and the engagement of the clutch plates (CP1, CP2) is completed. That is, in the above configuration, when a rotational load is input to the first shaft (51), power is automatically transmitted from the second shaft (52) to the first shaft (51).
As will be described later in detail, the cam force (Fm) is set between the cam plates by setting the first shaft (51) in a free state, that is, by setting the first cam plate (53) in a free state. Thus, the clutch engagement between the clutch drum (61) and the third cam plate (56) is automatically released, and power is not transmitted from the second shaft (52) to the first shaft (51). .

  According to a second feature of the power cutting mechanism of the present invention, the fixing means (62) includes a friction surface (62a) that contacts the case (59) on the bottom surface and the second cam plate (55 on the side inner peripheral surface). ) And a spline tooth (62b) that is spline-coupled, and an elastic body (SP1) that is supported at one end by the second cam plate (55) and presses the friction surface (62a) against the case (59). That is.

  In the above configuration, the elastic body (SP1) presses the friction surface (62a) against the case (59), and the whole is fixed to the case (59). Therefore, the second cam plate (55) is stably rotated and stationary. Accordingly, when a rotational load is input to the first shaft (51), a differential rotation is generated between the first cam plate (53) and the second cam plate (55). It is possible to generate a cam force (Fp) that moves the second cam plate (55) to the left in the axial direction.

  A third feature of the power cutting mechanism according to the present invention is that a circlip (SC1) for restricting the axial movement of the second cam plate (55) is provided on the inner peripheral surface of the side of the fixing means (62). A gap (A) is formed between the circlip (SC1) and the second cam plate (55).

  In the above configuration, when the second cam plate (55) moves by the gap, the friction surface (62a) of the fixing means (62) is separated from the case (59) by hitting the circlip (SC1), As a result, the second cam plate (55) is brought into a rotation-free state, and the cam force (Fp) generated due to the differential rotation between the first cam plate (53) and the second cam plate (55) is zero. Thus, the function of the second cam plate (55) can be terminated.

  According to a fourth aspect of the power cutting mechanism of the present invention, the engaging portion (D) of the third cam plate (56) with respect to the second cam plate (55) has a step that descends to the left in the axial direction. It is that you are.

  In the above configuration, when the third cam plate (56) moves to the left in the axial direction, the second cam plate (55) is preferably moved in the same direction, and the clutch is thereby brought into contact with the second cam plate (55). The plate (CP2) and the clutch plate (CP1) are pressure-bonded, and the clutch drum (61) and the third cam plate (56) are clutch-engaged. As a result, the third cam plate ( 56) can be rotationally driven.

  According to a fifth feature of the power cutting mechanism of the present invention, a step plate (54) rising to the left in the axial direction is provided on the second shaft (52), and the clutch drum (61) is in contact below. A possible first step surface (54a) and a second step surface (54b) supporting one end of the elastic body (SP3) for urging the clutch drum (61) are formed above, respectively. It is.

  In the above configuration, when the third cam plate (56) moves to the left in the axial direction and further presses the second cam plate (55) against the clutch drum (61), the third cam from the right side with respect to the clutch drum (61). The cam force (Fm) acts on the plate (56), and the elastic force (F3) of the elastic body (SP3) and the vertical drag force (F4) from the first step surface (54a) can be applied from the left side. The clutch engagement between the clutch drum (61) and the third cam plate (56) is made stronger.

  According to the power cutting mechanism (50) of the present invention, when a rotational load is input to the first shaft (51), power is automatically transmitted from the second shaft (52) to the first shaft (51). It becomes like this. Conversely, by setting the first shaft (51) in a free state, power is not automatically transmitted from the second shaft (52) to the first shaft (51). Therefore, by applying the power cutting mechanism (50) to the four-wheel drive system, the mechanism related to the drive mode between the two-wheel drive mode and the four-wheel drive in the part-time four-wheel drive vehicle is simplified and the cost is increased. Can be suppressed.

It is explanatory drawing which shows the four-wheel drive system to which the power cutting mechanism of this invention is applied. It is principal part cross-sectional explanatory drawing which shows the power cutting mechanism of this invention. It is explanatory drawing which shows operation | movement when the pilot cam which concerns on the power cutting mechanism of this invention moves to the axial direction left side. It is explanatory drawing which shows operation | movement when the main cam which concerns on the power cutting mechanism of this invention moves to the axial direction left side. It is explanatory drawing which shows operation | movement when the clutch drum and main cam which concern on the power cutting mechanism of this invention engage in a clutch. It is explanatory drawing which shows operation | movement of the ball cam mechanism which concerns on the power cutting mechanism of this invention.

  Hereinafter, the present invention will be described in more detail with reference to embodiments shown in the drawings.

FIG. 1 is an explanatory diagram showing a four-wheel drive system 100 according to the present invention.
The operation of this four-wheel drive system 100 will be described later with reference to FIGS. 2 to 5. However, when the second power cutting mechanism 80 is connected during two-wheel driving, the first power cutting mechanism 50 of the present invention is automatically operated. When the second power cutting mechanism 80 is disconnected during the four-wheel driving, the first power cutting mechanism 50 of the present invention is automatically disconnected and the two-wheel driving is performed. Automatically shifts to 4-wheel drive. In addition, the 1st power cutting mechanism 50 of this invention is a mechanical type.

  The main configuration of the four-wheel drive system 100 includes an engine 1 that generates power, a transmission 2 that shifts power to a desired rotational speed, and power that has been shifted to a desired rotational speed to the left and right front tires (front wheels). Front differential 3 that distributes to 5L and 5R while absorbing the differential rotation between both wheels, left and right front drive shafts 4L and 4R that transmit power, and left and right front that move the vehicle forward or backward by transmitting power to the road surface The first power cutting mechanism 50 of the present invention that interrupts (on / off) the transmission of power to the tires (front wheels) 5L and 5R and the propeller shaft 6, and the power when the first power cutting mechanism 50 is connected to the rear The propeller shaft 6 that transmits to the differential 7 and the power transmitted from the propeller shaft 6 to both the left and right rear tires (rear wheels) 9L and 9R Rear differential 7 that distributes each wheel while absorbing differential rotation between wheels, left and right rear drive shafts 8L and 8R that transmit power, and left and right rear tires (rear wheels) that transmit power to the road surface to move the vehicle forward or backward The four-wheel drive system 100 includes 9L and 9R. Hereinafter, each configuration will be described in more detail.

  The first power cutting mechanism 50 is a first gear G1 provided at the shaft end of the propeller shaft 6 as a gear related to power transmission, and a second gear provided at the shaft end of the first shaft 51 and meshes with the first gear G1. A gear G2 and a third gear G3 that is provided at the shaft end of the second shaft 52 and meshes with the ring gear 3a of the front differential 3 are provided. Although details will be described later with reference to FIGS. 2 to 5, two types of ball cam mechanisms having different functions of a pilot cam 55 (FIG. 2) and a main cam 56 (FIG. 2) are provided. The power transmitted from the front differential 3 is transmitted to the propeller shaft 6 using the cam force Fp (FIG. 3) and the cam force Fm (FIG. 4) related to the main cam 56, and the power transmitted from the front differential 3 is transmitted. When cutting, the power is cut by setting the cam force Fm and the cam force Fp to zero.

  The rear differential 7 has an electronically controlled coupling mechanism (second power cutting mechanism 80 to be described later) that intermittently controls power transmission between the propeller shaft 6 and the rear wheel. The form of the second power cutting mechanism 80 is not particularly limited.

  Between the right side gear 74R and the right rear wheel 9R of the rear differential 7, for example, an electronically controlled second power cutting mechanism 80 for intermittently transmitting power is provided. If the second power cutting mechanism 80 is not provided, if the differential rotation between the left and right rear wheels 9L, 9R (left and right rear drive shafts 8L, 8R) is zero, the left and right side gears 74L, 74R and the pinion gears 73, 73 As a result, the ring gear 72 is driven to rotate, and the bevel gear 71 meshing with the ring gear 72 is rotated. As a result, a part of the engine power is used to rotate the mechanism that does not contribute to the movement of the vehicle. The fuel consumption rate will deteriorate. By providing the second power cutting mechanism 80, when the second power cutting mechanism 80 is off, the left rear drive shaft 8L (left side gear 74L) is replaced by the right rear drive shaft 8R (right side gear) while the vehicle is traveling. 74R), the differential rotation is absorbed by the rotation of the pinion gears 73 and 73, and the ring gear 72 is not rotationally driven. As a result, the bevel gear 71 meshing with the pinion gears 73 is not rotated. As a result, part of the engine power is not used for rotation of a mechanism that does not contribute to the movement of the vehicle, and the fuel consumption rate of the vehicle does not deteriorate. In the four-wheel drive system 100, the second power cutting mechanism 80 automatically connects / disconnects a switch for switching between two-wheel driving and four-wheel driving, that is, the first power cutting mechanism 50 of the present invention. It functions as a switch.

FIG. 2 is an explanatory cross-sectional view of a main part showing the first power cutting mechanism 50 of the present invention. For convenience of explanation, the first, second, and third gears G1, G2, and G3 are omitted.
Unlike the cutting mechanism using the conventional ball cam mechanism, the first power cutting mechanism 50 does not have a piston mechanism for pressing the ball cam mechanism against the clutch mechanism, and a main cam 56 corresponding to a conventional clutch hub has a first shaft. 51, the clutch drum 61 and the main cam 56 are engaged with each other when the clutch drum 61 and the main cam 56 are engaged with each other. The cam force Fm generated due to the differential rotation between the main cam 56 and the cam plate 53 (FIG. 4). ), And the connection between the main cam 56 and the first shaft 51 is made via the second ball 58. On the other hand, in order to generate the cam force Fm, the pilot cam 55 is rotationally restrained by the friction plate 62 and is axially driven by the cam force Fp (FIG. 3) generated due to the differential rotation with the cam plate 53. The clutch drum 61 is pressed and the clutch plate CP2 of the clutch drum 61 and the clutch plate CP1 of the main cam 56 are fastened to such an extent that the driving force from the second shaft 52 is transmitted to the main cam 56. It will serve a pilot function. Briefly speaking, a series of operations related to the connection is as follows: rotation of the first shaft 51 → generation of cam force Fp → left movement of the pilot cam 55 → pressing of the pilot cam 55 against the clutch drum 61 → half of the clutch plates CP1 and CP2 Fastening → Rotation of main cam 56 → Generation of cam force Fm → Left movement of main cam 56 → Separation of friction surface 62a → Free rotation of pilot cam 55 → Clutch plates CP1 and CP2 are fastened. Hereinafter, the configuration of the first power cutting mechanism 50 will be described.

  The first power cutting mechanism 50 includes a first shaft 51 connected to the propeller shaft 6 via first and second gears G1 and G2, and a third gear G3 that is divided coaxially with the first shaft 51. A second shaft 52 connected to the front differential 3 via a cam plate 53 integrated perpendicularly to the first shaft 51 and a step plate 54 integrated orthogonally to the second shaft 52. A pilot cam 55 that presses the clutch drum 61, a main cam 56 that moves the pilot cam 55 to the left in the axial direction, a first ball 57 that generates a cam force Fp that moves the pilot cam 55 to the left, and a main cam 56 Is provided with a second ball 58 for generating a cam force Fm for moving the shaft to the left and a first bearing B1 for supporting the first shaft 51 in the radial direction. 1 case 59, a second case 60 provided with a second bearing B2 for supporting the second shaft 52, a clutch drum 61 in which a plurality of clutch plates CP2 are laminated on the inner peripheral surface, and a ground on the first case 59 Thus, the rotation of the pilot cam 55 is suppressed and the friction plate 62 that serves as a guide when the pilot cam 55 moves in the axial direction, the third bearing B3 that supports the cam plate 53 in the axial direction, and the second spring SP2 The fourth bearing B4 for applying an elastic force to the pilot cam 55, the fifth bearing B5 for applying the pressure of the pilot cam 55 to the clutch drum 61, and the friction surface 62a of the friction plate 62 are pressed against the inner peripheral surface of the first case 59. The first spring SP1, the second spring SP2 urging the pilot cam 55 to the right in the axial direction, and the clutch drum 61. A third spring SP3 biased rightward in the direction, and an engagement member for restricting axial movement of the pilot cam 55 and separating the friction surface 62a of the friction plate 62 from the inner peripheral surface of the first case 59. One circlip SC1 and a second circlip SC2 for restricting movement of the clutch drum 61 in the axial direction are provided. Hereinafter, each configuration will be further described.

  The cam plate 53 forms a ball cam mechanism in cooperation with the pilot cam 55 and the first ball 57 or the main cam 56 and the second ball 58. A first right cam groove 53a in which the first ball 57 is fitted and a second right cam groove 53b in which the second ball 58 is fitted are formed on the left surface of the cam plate 53, respectively. On the other hand, a first left cam groove 55a and a second left cam groove 56b corresponding to the first right cam groove 53a and the second right cam groove 53b are formed on each surface of the pilot cam 55 and the main cam 56 facing the cam plate 53, respectively. Each is formed. In addition, each cam groove is comprised so that the depth may become shallow gradually along the circumferential direction, and it may become flush, as FIG. 6 may show. Further, when the cam plate 53 and the pilot cam 55 rotate relative to each other in the arrow direction shown in FIG. 6B, a cam force Fp is generated. It should be noted that when the pilot cam 55 is free of rotation (when no rotational load is applied), the first ball 57 has grooves 55a and 53a as shown in FIG. 6 (c). The cam force Fp is not generated. The same applies to the main cam 56 and the cam plate 53 as well.

  A first step surface 54a and a second step surface 54b are formed on the left side of the step plate 54, respectively. Spline teeth 54c are formed on a surface orthogonal to the first step surface 54a, and the clutch drum 61 can move between the first step surface 54a and the second circlip SC2 in the axial direction. On the other hand, one end of a third spring SP3 is attached to the second step surface 54b.

  The pilot cam 55 is splined to the inner peripheral surface of the friction plate 62 and is movable in the axial direction while being restricted in rotation by the friction plate 62. The movable range is regulated by the first circlip SC1. Therefore, the pilot cam 55 can move by the gap A to the left in the axial direction.

  One end of the first spring SP1 is attached to the surface of the pilot cam 55 facing the friction plate 62, and presses the friction surface 62a against the inner peripheral surface of the first case 59. A fourth bearing B4 is attached to the opposite surface, and receives the elastic force F2 of the second spring SP2. Further, a fifth bearing B5 that receives the end plate 61a of the clutch drum 61 is attached to the leftmost front end portion, and a gap C is formed between the end plate 61a and the fifth bearing B5.

  The main cam 56 is mounted on the first shaft 51 so as to freely move and rotate in the axial direction, engages with the clutch drum 61 via the clutch plate CP1, and engages with the first shaft 51 via the second ball 58. Yes. Therefore, a plurality of clutch plates CP1 are spline-coupled to the inner peripheral surface of the main cam 56 at the left end in the axial direction and are alternately arranged with respect to the clutch plate CP2 of the clutch drum 61. Therefore, when the main cam 56 moves to the left in the axial direction, the clutch plate CP1 and the clutch plate CP2 are pressure-bonded to each other. Further, a step D that is lowered to the left in the axial direction is formed on the surface to be joined to the pilot cam 55, and when the main cam 56 moves to the left in the axial direction due to the step D, the step is engaged with the pilot cam 55. Therefore, although details will be described later with reference to FIG. 4, when a differential rotation occurs between the main cam 55 and the cam plate 53, a cam force Fm is generated, and the cam force Fm causes the main cam 56 to move to the left in the axial direction. The pilot cam 55 is forcibly moved to the left in the axial direction, and the clutch drum 61 is pressed.

  The clutch drum 61 is splined to the second shaft 52 and is movable in the axial direction, and its movable range is restricted by the second circlip SC2 and the first step surface 54a of the step plate 54. In the initial state (two-wheel drive state), it is restrained by the second circlip SC2 while being urged to the right in the axial direction by the third spring SP3. In this case, a gap B is formed between the step plate 54 and the first step surface 54a.

  Further, the plurality of clutch plates CP2 are splined to the inner peripheral surface thereof, and are not rotatable relative to the clutch drum 61 and movable in the axial direction, and the movable range is restricted by the end plate 61a and the convex portion 61b. Therefore, the second shaft 52, the clutch drum 61, and the clutch plate CP2 are synchronized with respect to rotation. The clutch plates CP2 are alternately arranged with respect to the clutch plate CP1, and the cam force Fm of the main cam 56, the elastic force F3 of the third spring SP3 (FIG. 4), and the vertical drag F4 from the first step 54a (FIG. 4). ) Is frictionally engaged with the clutch plate CP1. In the initial state (two-wheel drive state), the clutch plate CP2 and the clutch plate CP1 are in the released state.

  The friction plate 62 is fixed to the first case 59 such that the friction surface 62a is pressed against the inner peripheral surface of the first case 59 by the first spring SP1. Regarding the friction surface 62a, when the main cam 56 moves to the left side in the axial direction, the pilot cam 55 engaged with the first circlip SC1 is forcibly moved to the left side in the axial direction. The case 59 is separated from the inner peripheral surface of the case 59, so that the pilot cam 55 becomes free to rotate.

3-5 is explanatory drawing which shows operation | movement of the 1st power cutting mechanism 50 of this invention. 3 shows the operation when the pilot cam 55 moves to the left in the axial direction, FIG. 4 shows the operation when the main cam 56 moves to the left in the axial direction, and FIG. 5 shows the clutch engagement between the clutch drum 61 and the main cam 56. Each operation is shown.
Further, the initial state is the state shown in FIG. 2 (two-wheel drive constant running state). That is, the first shaft 51 (propeller shaft 6) is in a stopped state, the friction surface 62a of the friction plate 62 is grounded to the inner peripheral surface of the first case 59, and between the pilot cam 55 and the first circlip SC1. A gap C is formed between the fifth bearing B5 of the pilot cam 55 and the end plate 61a of the clutch drum 61, and a gap B is formed between the first step surface 54a of the step plate 54 and the clutch drum 61. Each is formed. In this state, there is no differential rotation between the first shaft 51 and the pilot cam 55 or between the first shaft 51 and the main cam 56, and the pilot cam 55 and the main cam 56 are in the first ball 57 or the second ball 58. No cam power has been received. On the other hand, the second shaft 52, the clutch drum 61, the third spring SP3, and the second circlip SC2 have a gear ratio (= (the number of teeth of the ring gear 3a) / (the number of teeth of the third gear G3). )).

Further, looking at the balance of forces in the axial direction of the pilot cam 55 in the initial state, the elastic force F1 received from the first spring SP1, the elastic force F2 received from the second spring SP2, and the stationary first ball on the pilot cam 55 Three forces of reaction Fp (not cam force) received from 57 are balanced. Therefore, the balance of force (force balance) at this time is expressed by the following formula 1.
Formula 1: F2 = Fp + F1

Now, when the second power cutting mechanism 80 of FIG. 1 is connected (turned on), the rotation of the left and right rear wheels 9L, 9R causes the left and right rear drive shafts 8L, 8R → left and right side gears 74L, 74R → pinion gears 73, 73 → ring gear 72 → It is transmitted to the first shaft 51 along the transmission path of the bevel gear 71 → propeller shaft 6 → first gear G1 → second gear G2 → first shaft 51. When rotation is transmitted to the first shaft 51, the first shaft 51 rotates, and a differential rotation occurs between the pilot cam 55 that is rotatingly stationary by the friction plate 62 and the rotating cam plate 53, As a result, the cam force Fp from the first ball 57 acts on the pilot cam 55, thereby causing the balance of the force to be lost, and the pilot cam 55 starts to move to the left in the axial direction. Accordingly, the balance of force (force balance) at this time is expressed by the following formula 2. However, with respect to Equation 1, Fp increases, F2 increases, and F1 decreases.
Formula 2: F2 <F1 + Fp

As shown in FIG. 3, when the pilot cam 55 moves to the left in the axial direction by the gap C, it abuts against the end plate 61a of the clutch drum 61 and starts to push the clutch drum 61. As a result, the clutch drum 61 moves to the left in the axial direction. The pilot cam 55 receives the elastic force F3 of the third spring SP3. In this case, the main cam 56 does not reach the rotational difference from the cam plate 53 until the cam force Fm is generated, so that the main cam 56 is stationary with respect to the axial direction. Accordingly, the balance of force (force balance) at this time is expressed by the following formula 3. However, with respect to Equation 2, Fp increases, F2 increases, F1 decreases, and F3 is newly generated.
Formula 3: F2 + F3 <F1 + Fp

When the pilot cam 55 further moves to the left in the axial direction, the degree of engagement between the clutch plate CP1 of the main cam 56 and the clutch plate CP2 of the clutch drum 61 reaches a capacity capable of transmitting the engine torque from the second shaft 52. As a result, the main cam 56 begins to rotate, and a differential rotation between the main cam 56 and the cam plate 53 occurs. When the differential rotation exceeds a predetermined value, the main cam 56 receives the cam force Fm from the second ball 58 and receives a shaft. Start moving to the left in the direction. Therefore, the balance of force (force balance) at this time is expressed by the following formula 4. However, Fp decreases with respect to Equation 3, and Fm is newly generated.
Formula 4: F2 + F3 <F1 + Fp + Fm

As shown in FIG. 4, when the main cam 56 further moves to the left in the axial direction, the main cam 56 is fitted to the step D of the pilot cam 55 and moves to the left in the axial direction together with the pilot cam 55. At this time, the cam force Fp from the first ball 57 against the pilot cam 55 becomes zero. Accordingly, the balance of force (force balance) at this time is expressed by the following formula 5. However, F2 increases, F3 increases, Fm newly occurs, and Fp becomes zero with respect to Equation 4.
Formula 5: F2 + F3 <F1 + Fm

As shown in FIG. 5, when the main cam 56 moves further to the left in the axial direction, the gap A becomes zero, the friction surface 62a of the friction plate 62 is separated from the inner peripheral surface of the first case 59, and the friction becomes zero. The elastic force F1 of the first spring SP1 is canceled by the reaction from the first circlip SC1 and becomes zero. When the main cam 56 further moves to the left in the axial direction, the gap B becomes zero. As a result, the clutch drum 61 hits the first step surface 54a of the step plate 54, and the vertical drag F4 acts on the main cam 56, thereby A power transmission path between the shaft 51 and the second shaft 52 is established, and the transition from the two-wheel drive to the four-wheel drive is completed. The force balance at this time is expressed by the following formula 6. However, with respect to Equation 5, F2 increases, F3 increases, Fm increases, F4 is newly generated, and F1 becomes zero.
Formula 6: F2 + F3 + F4 = Fm

  In summary, when the first shaft 51 rotates, a cam force Fp is generated between the pilot cam 55 and the cam plate 53. With this cam force Fp, the pilot cam 55 moves to the left in the axial direction and presses the clutch drum 61. Thus, the clutch plates CP1 and CP2 are in a semi-engaged state, the main cam 56 is rotationally driven by the driving force from the second shaft 52, and a cam force Fm is generated between the cam plate 53, and the main cam 56 is generated by the cam force Fm. Starts moving to the left in the axial direction. By this movement, the pilot cam 55 is further moved to the left in the axial direction, and the clutch drum 61 is further pressed. Thereafter, the friction surface 62a of the friction plate 62 is separated from the inner peripheral surface of the first case 59 so that the pilot cam 55 can freely rotate, and the engagement of the clutch plates CP1 and CP2 is completed.

  Regarding the transition from the four-wheel drive to the two-wheel drive, the connection of the first power cutting mechanism 50 is released by cutting (turning off) the second power cutting mechanism 80. That is, by cutting the second power cutting mechanism 80, the propeller shaft 6 is brought into a rotation free state, and as a result, the first shaft 51 is also brought into a rotation free state, and the cam force Fm received from the second ball 58 in the main cam 56 is reduced. The main cam 56 and the pilot cam 55 are moved to the right in the axial direction by the elastic force F2 of the second spring SP2, the elastic force F3 of the third spring SP3, and the drag F4 received from the first step surface 54a of the step plate 54. It is done. As a result, the engagement between the clutch plate CP1 of the main cam 56 and the clutch plate CP2 of the clutch drum 61 is released, whereby the power transmission between the first shaft 51 and the second shaft 52 is cut off, and from the four-wheel drive 2 The transition to wheel drive is complete.

  As described above, according to the power cutting mechanism 50 of the present invention, when a rotational load is input to the first shaft 51, power is automatically transmitted from the second shaft 52 to the first shaft 51. Conversely, by setting the first shaft 51 in a free state, power is not automatically transmitted from the first shaft 52 to the first shaft 51. Therefore, by applying the power cutting mechanism 50 to a four-wheel drive system, the mechanism related to the drive mode between the two-wheel drive mode and the four-wheel drive in a part-time four-wheel drive vehicle is simplified and the cost is reduced. It becomes possible to do.

1 Engine 2 Transmission 3 Front differential 4 Front drive shaft 5 Front wheel 6 Propeller shaft 7 Rear differential 8 Rear drive shaft 9 Rear wheel 50 First power cutting mechanism 51 First shaft 52 Second shaft 53 Cam plate 54 Step plate 55 Pilot cam 56 main cam 57 first ball 58 second ball 59 first case 60 second case 61 clutch drum 62 friction plate 80 second power cutting mechanism
Fp Cam force related to pilot cam
Fm 100 cam force on the main cam 4-wheel drive system

Claims (5)

A first shaft and a second shaft divided on the same axis; a first cam plate provided perpendicular to the first shaft; a second cam plate provided facing the first cam plate; A third cam plate facing the first cam plate and adjacent to the second cam plate on the radially inner side, and a first cam plate sandwiched between the first cam plate and the second cam plate. Power provided with one ball, a second ball sandwiched between the first cam plate and the third cam plate, and a clutch drum which is axially movable with respect to the second shaft and synchronized with the rotational direction A cutting mechanism,
The second cam plate is configured to be non-rotatable and axially movable by a fixing means, and has a pressing portion that is biased to the right in the axial direction by an elastic body and presses the clutch drum,
The third cam plate is freely attached on the first shaft and is engaged with the plurality of clutch plates alternately arranged on the plurality of clutch plates of the clutch drum and the second cam plate in the axial direction. Having an engaging part that fits,
The power cutting mechanism according to claim 1, wherein the clutch drum is urged to the right in the axial direction by an elastic body.   The fixing means includes a friction surface that contacts the case on a bottom surface, spline teeth that are splined to the second cam plate on a side inner peripheral surface, and one end supported by the second cam plate, and the friction surface serving as the case. The power cutting mechanism according to claim 1, further comprising an elastic body to be pressed.   A circlip for restricting the axial movement of the second cam plate is provided on the inner peripheral surface of the side portion of the fixing means, and a gap is formed between the circlip and the second cam plate. The power cutting mechanism according to claim 1 or 2.   The power cutting mechanism according to any one of claims 1 to 3, wherein the engaging portion of the third cam plate with respect to the second cam plate forms a step that descends to the left in the axial direction.   A step plate that rises to the left in the axial direction is provided on the second shaft, a first step surface on which the clutch drum can be contacted below, and one end of the elastic body that urges the clutch drum above. The power cutting mechanism according to any one of claims 1 to 4, wherein a second step surface for supporting each of the first and second step surfaces is formed.

Images