JP2010060109A - Power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmission device automatically and promptly increasing torque transmitted as a difference of rotational frequency between a first rotating member and a second rotating member increases without using external power. <P>SOLUTION: The power transmission device 10 is provided with a cam member 70 which has a cam surface 72 facing the radial inner side of a rotating shaft S and set so that a radial distance with the rotating shaft S is changed in accordance with the rotating angle position around the rotating shaft S and the radial distance and its change amount increase toward one side (front side) in the axial direction of the rotating shaft S and which is rotated around the rotating shaft S together with the second rotating member 20; and with a pump member 40 rotated around the rotating shaft S together with the first rotating member 30, sucking oil from a suction passage 52 to inside of a cylinder 41 by the reciprocation of a piston 44, driven by the cam surface 72, in the radial direction of the rotating shaft S within the cylinder 41 and discharging the oil to a discharge passage 56 provided in a passage switching part 50 of the second rotating member 20. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power transmission device with a differential limiting function.

  Conventionally, when the vehicle is turning, as a device that absorbs the difference in rotational speed between the left and right drive wheels, and in a four-wheel drive vehicle, one of the front wheels and the rear wheels slipped. Sometimes, a differential device (differential device) is used as a device that absorbs the difference in rotational speed between the front and rear wheels. In such a differential device, if a slip occurs on one side between the left and right drive wheels or the front and rear wheels, the torque transmitted to the other side may be reduced, making it impossible to drive the vehicle. is there. Therefore, a power transmission device with a differential limiting function is known as a device for limiting the function of the differential device to some extent and transmitting torque to the other even if slip occurs on one side.

  Patent Document 1 listed below faces the inner side in the radial direction of the rotation axis (axis A1), changes the radial distance from the rotation axis in accordance with the rotation angle position around the rotation axis, and the rotation axis. An outer race (output-side member) having a cam surface (22) whose radial distance increases toward one side in the axial direction, and is provided so as to be displaceable in the axial direction of the rotary shaft with respect to the outer race. Rotating around the rotation shaft together with the input shaft, and the piston is driven by the cam surface to reciprocate in the cylinder, so that oil is sucked into the cylinder from the suction passage and discharged to the discharge passage. A power transmission device having an inner race (input side member) that is a member on the input side capable of the above is disclosed.

  In the power transmission device of Patent Document 1, hydraulic pressure is supplied from the outside to the hydraulic chamber (31), and the hydraulic pressure is controlled to control the axial displacement of the rotation shaft of the inner race with respect to the outer race. A technique for changing the stroke of a piston provided in a race has been proposed. It has also been proposed to control the difference in rotational speed between the inner race and the outer race by restricting the flow rate of oil discharged from the inner race to the discharge passage with a discharge control valve.

JP 2007-239759 A (see page 12)

  By the way, in the power transmission device described in Patent Document 1, as the rotational speed difference between the first rotating member (inner race) and the second rotating member (outer race) increases, the rotational speed difference is suppressed. The force for engaging the first rotating member and the second rotating member in the circumferential direction of the rotating shaft, that is, the torque transmitted between the first rotating member and the second rotating member is increased, thereby limiting the differential. In order to use it as a power transmission device with functions, it is necessary to supply hydraulic pressure to be displaced in the axial direction of the rotation axis of the inner race from the outside, and discharge control that restricts the flow rate of oil discharged from the inner race to the discharge passage It is necessary to provide a valve. The power transmission device with a differential limiting function requires power such as hydraulic supply from the outside, dedicated control, etc. as the rotational speed difference between the first rotating member and the second rotating member increases. There is a need for a novel structure that can increase the torque transmitted between the first rotating member and the second rotating member automatically and quickly without the need to do so.

  The present invention has been made in view of the above, and is transmitted between the first rotating member and the second rotating member as the rotational speed difference between the first rotating member and the second rotating member increases. It is an object of the present invention to provide a power transmission device capable of automatically and quickly increasing torque without using external power.

  In order to achieve the above object, a power transmission device according to the present invention faces a first rotating member and a second rotating member that are relatively rotatable about a rotating shaft, and a radially inner side of the rotating shaft, The radial distance to the rotation axis changes according to the rotation angle position around the rotation axis, and the radial distance and the amount of change are set to increase toward one side in the axial direction of the rotation axis. A cam surface is provided so as to be displaceable in the axial direction of the rotation shaft with respect to the second rotation member, the cam member rotating about the rotation shaft together with the second rotation member, and the rotation shaft together with the first rotation member The piston rotates along the cam surface and reciprocates in the cylinder in the radial direction of the rotation shaft, whereby oil is sucked into the cylinder from the suction passage provided in the second rotating member, Oil in the discharge passage provided in the second rotating member A pump member capable of circulating oil in the second rotating member, and a biasing member for biasing the cam member toward the one side with respect to the second rotating member. .

  In the power transmission device, the second rotation member is provided on the one side with respect to the pump member, and the suction passage and the discharge passage are alternately arranged in the circumferential direction of the rotation shaft on the end surface on the pump member side, The pump member may be in contact with the end surface, and the suction passage or the discharge passage may have a passage switching portion that communicates with the cylinder.

  The power transmission device may include a discharge-side orifice portion that reduces a flow passage cross-sectional area in the middle of the discharge passage as the cam member is displaced to the other side in the axial direction of the rotating shaft.

  The power transmission device may include a suction-side orifice portion that reduces a cross-sectional area of the passage in the middle of the suction passage as it is positioned on the one side together with the cam member.

  In the power transmission device described above, the inner wall of the discharge-side orifice hole communicating with the adjacent discharge passage in the discharge-side orifice portion is configured such that the inner wall on the other side has a larger area than the inner wall on the one side. Can be.

  In the power transmission device described above, a volume chamber can be provided that communicates with the discharge passage and accommodates the urging member to reduce pressure fluctuation in the discharge passage.

  In the above power transmission device, the pump member has a piston spring that biases the piston radially outward of the rotation shaft, and when there is no rotational speed difference between the first rotation member and the second rotation member, The biasing force that biases the cam member toward the one side by the biasing member is set to be larger than the thrust force that acts on the cam member from the pump member by the biasing force of the piston spring. be able to.

  According to the present invention, as the rotational speed difference between the first rotating member and the second rotating member increases, the force with which the pump member presses the cam member radially outward of the rotating shaft increases, and the pump member and the cam member Can be increased in the circumferential direction of the rotating shaft, and the torque transmitted between the first rotating member and the second rotating member can be increased. The force (thrust force) generated according to the force with which the pump member presses the cam member radially outwardly is opposed to the return biasing force that biases the cam member toward the one side (front side). Displacement of the cam member to the other side (rear side) increases the stroke of the piston and increases the flow rate of oil circulated by the pump member, thereby increasing the hydraulic pressure received by the piston in the stroke of discharging the oil. Let As a result, the engagement force and the thrust force acting between the pump member and the cam member are further increased, and the torque transmitted between the first rotating member and the second rotating member can be quickly transmitted without using external power. Can be increased.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to this embodiment (hereinafter referred to as an embodiment). In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same.

  The configuration of the power transmission device according to the present embodiment will be described with reference to FIGS. FIG. 1 is a cross-sectional view of a power transmission device and a differential device connected to the power transmission device. FIG. 2 is an enlarged cross-sectional view of the power transmission device. FIG. 3 is a cross-sectional view taken along line BB in FIGS. 1 and 2. 4 is a cross-sectional view taken along the line CC in FIGS. 1 and 2. FIG. 5 is a cross-sectional view showing the periphery of the discharge-side orifice hole provided in the middle of the discharge passage. 1 and 2 are cross-sectional views taken along line AA in FIG.

  As shown in FIG. 1, the power transmission device 10 includes a first rotating member 30 and a second rotating member 20 that can rotate relatively around a rotation axis S indicated by a one-dot chain line S in the drawing. Have. For example, in a vehicle equipped with a prime mover, the power transmission device 10 includes a propulsion shaft 3 (indicated by a two-dot chain line in the figure) that transmits mechanical power from the prime mover, and mechanical power from the propulsion shaft 3 to the left and right rear. It is interposed between the differential unit 6 that distributes the ring.

  In the following description, the axial direction of the rotating shaft S is simply referred to as “axial direction”, and the radial direction of the rotating shaft S is simply referred to as “radial direction”. Further, in the axial direction of the rotary shaft S, the side where the propulsion shaft 3 is provided is referred to as “front side”, and the side where the differential device 6 is provided is referred to as “rear side”.

  The second rotating member 20 includes a cylindrical portion 25 having a substantially cylindrical shape with the rotation axis S as the center, and a rear end portion 23 that has a substantially disk shape and closes an opening on the rear side in the axial direction of the cylindrical portion 25. And a front end portion 27 that closes the opening on the front side in the axial direction of the tubular portion 25 and a passage switching portion 50 that transfers oil between the pump member 40 described later. The rear end portion 23 and the front end portion 27 are integrally coupled to the cylindrical portion 25 by bolts or the like, and oil can be enclosed in the second rotating member 20. The rear end 23 is coupled to a shaft 22 that extends rearward about the rotation axis S, and a drive pinion 21 that rotates about the rotation axis S is coupled to the shaft 22. The passage switching unit 50 of the second rotating member 20 will be described later.

  On the other hand, the first rotation member 30 includes a large diameter portion 32 extending along the rotation axis S, a flange portion 31 coupled to one end of the large diameter portion 32, and the rotation axis S from the other end of the large diameter portion 32. And a small-diameter portion 34 that extends. The large diameter portion 32 is supported by the bearing 28 provided at the front end portion 27 so as to be rotatable with respect to the second rotating member 20. The small diameter portion 34 is rotatably supported by a bearing 24 provided at the rear end portion 23. The flange portion 31 is coupled to the propulsion shaft 3. In this way, the first rotating member 30 rotates together with the propelling shaft 3 and is rotatable relative to the second rotating member 20 around the rotating shaft S.

  The flange portion 31 of the first rotating member 30 is coupled to the propulsion shaft 3. On the other hand, the drive pinion 21 of the second rotating member 20 meshes with the ring gear 9 of the differential 6 and is configured to be able to rotate the ring gear 9. The differential device 6 distributes the mechanical power received by the ring gear 9 to the left and right drive shafts 8a and 8c and transmits them to rear wheels (not shown) coupled to the drive shafts 8a and 8c, respectively. On the other hand, the propulsion shaft 3 is engaged with the front wheel via a differential device or the like (not shown).

  As shown in FIG. 2, in the power transmission device 10, the cylindrical portion 25 of the second rotating member 20 rotates around the rotating shaft S together with the second rotating member 20, and is radially inward of the rotating shaft S. A cam member 70 is provided with a cam surface 72 facing the surface. The cam surface 72 is configured such that a radial distance from the rotation shaft S (hereinafter referred to as a radial distance) increases as the axial direction moves toward the front side. The detailed structure of the cam surface 72 will be described later.

  On the outer wall of the cam member 70, spline teeth having “tooth lines” extending in the axial direction are formed. On the other hand, on the inner wall of the cylindrical portion 25 of the second rotating member 20, the spline groove 26 that meshes with the spline teeth. Is formed. The cam member 70 is spline-coupled with the cylindrical portion 25 of the second rotating member 20, and can slide (displace) in the axial direction within the cylindrical portion 25, that is, displaceable with respect to the second rotating member 20. It is configured.

  Further, the power transmission device 10 rotates together with the first rotating member 30 around the rotation axis S, and the piston 44 is driven along the cam surface 72 to reciprocate in the cylinder 41, whereby oil is supplied to the cylinder. A pump member 40 that sucks into and discharges into 41 is provided.

  As shown in FIGS. 2 and 3, the pump member 40 is a substantially disk-shaped member having a through hole in the center, and is a cylinder that is a cylindrical hole having an axial center in the radial direction of the rotation shaft S. 41 are arranged at regular intervals in the circumferential direction of the rotation axis S. A piston 44 is accommodated in the axial direction of the rotation axis S in the cylinder 41, and the piston 44 can reciprocate in the radial direction of the rotation axis S in the cylinder 41. A spherical rolling element 45 that comes into contact with the cam surface 72 is provided on the radially outer side of the piston 44, and the piston 44 holds the rolling element 45. A piston spring 43 is provided on the radially inner side of the piston 44 as a biasing member that biases the piston 44 radially outward, and the rolling element 45 held by the piston 44 is connected to the cam surface of the cam member 70. 72. Between the rolling element 45 of the pump member 40 and the cam surface 72 of the cam member 70, a force (hereinafter referred to as a thrust force) that the pump member 40 urges the cam member 70 toward the axial rear side acts. .

  In the cylinder 41, the piston 44 reciprocates in the cylinder 41 radially inward of the piston 44, so that the volume of the hydraulic chamber 46 in the cylinder 41 radially inward of the piston 44 decreases and increases. Further, the pump member 40 is formed with a suction / discharge passage 47 that is a passage that allows the hydraulic chamber 46 to communicate with a suction passage 52 and a discharge passage 56 of a passage switching unit 50 described later. That is, when the piston 44 moves radially outward, the pump member 40 increases the volume of the hydraulic chamber 46, sucks oil in the suction passage 52 from the suction / discharge passage 47, and moves the piston 44 radially inward. The volume of the hydraulic chamber 46 decreases, and oil is discharged from the suction / discharge passage 47 toward the discharge passage 56.

  Spline teeth having tooth lines extending in the axial direction are formed on the inner wall of the through hole of the pump member 40, while the spline groove meshing with the spline teeth is formed on the outer wall of the large diameter portion 32 of the first rotating member 30. 33 is formed. The pump member 40 is spline-coupled to the large diameter portion 32 of the first rotating member 30 and is configured to be slidable (displaceable) in the axial direction with respect to the first rotating member 30.

  Further, as shown in FIG. 2, a passage switching unit that transfers oil to and from the pump member 40 is provided at the front end portion 27 of the second rotating member 20 that is on the axial front side with respect to the pump member 40. 50 is press-fitted and provided. The passage switching unit 50 is composed of a cylindrical member centered on the rotation axis S. Inside the passage switching unit 50, a suction passage 52 through which the pump member 40 sucks oil from the suction / discharge passage 47 and a discharge passage 56 through which the pump member 40 discharges oil from the suction / discharge passage 47 are shafts of the rotary shaft S. Extending in the direction. The axially rear end surface 48 of the pump member 40 abuts on the axially rear end surface 55 of the passage switching unit 50.

  As shown in FIGS. 2 and 4, a circumferential groove 54 extending in the circumferential direction of the rotation shaft S is formed on the outer wall of the passage switching unit 50, and the circumferential groove 54 is connected via the communication hole 53. The suction passage 52 communicates with the suction passage 52. The suction passage 52 is supplied with oil from the suction passages (92, 93) provided in the front end portion 27 of the second rotating member 20 through the communication hole 53 and the circumferential groove 54. In addition, a circumferential groove 58 extending in the circumferential direction of the rotation shaft S is formed on the outer wall of the passage switching unit 50, and the circumferential groove 58 communicates with the discharge passage 56 via the communication hole 57. Yes. The discharge passage 56 allows oil to flow into the discharge passages (95, 97) provided in the front end portion 27 via the communication hole 57 and the circumferential groove 58.

  In the passage switching unit 50, the suction passages 52 and the discharge passages 56 are alternately arranged in the circumferential direction of the rotation shaft S. Note that the suction passages 52 and the discharge passages 56 are alternately arranged in the circumferential direction of the rotation axis S on the end surface 55 of the passage switching unit 50, and the suction passages 52 and the discharge passages 56 are open on the end surface 55. . In the present embodiment, six suction passages 52 and six discharge passages 56 are provided. The radial distances between the suction passage 52 and the discharge passage 56 and the rotary shaft S coincide with the radial distances between the suction / discharge passage 47 of the pump member 40 and the rotary shaft S.

  By bringing the front end face 48 of the pump member 40 into contact with the rear end face 55 of the passage switching section 50, the suction passage 52 or the discharge passage 56 and the suction / discharge passage 47 of the pump member 40 can be communicated with each other. It becomes possible. When the passage switching unit 50 and the pump member 40 are in contact with each other, when the first rotating member 30 and the second rotating member 20 rotate relatively, the suction / discharge passage 47 of the pump member 40 that rotates together with the first rotating member 30 is provided. The suction passage 52 and the discharge passage 56 of the passage switching unit 50 of the second rotating member 20 are alternately and intermittently communicated.

  On the other hand, as shown in FIG. 3, the cam surface 72 of the cam member 70 has a portion 72a (hereinafter referred to as the top) where the radial distance from the rotation axis S is the smallest in the same cross section orthogonal to the rotation axis S. And the part 72c (henceforth a bottom part) where radial distance with the rotating shaft S becomes the largest is arrange | positioned alternately by the predetermined | prescribed space | interval in the circumferential direction of the rotating shaft S, and is continuing smoothly. Six top portions 72a and six bottom portions 72c are arranged in a cross section orthogonal to the rotation axis S. The top portion 72 a is provided corresponding to the discharge passage 56, and the bottom portion 72 c is provided corresponding to the suction passage 52. Thus, the cam surface 72 is configured such that the radial distance from the rotation axis S periodically changes in accordance with the rotation angle position (rotation phase) about the rotation axis S.

  In addition, in the cam surface 72, the top portion 72a and the bottom portion 72c are set such that the radial distance from the rotation shaft S increases as the axial direction approaches the front end surface 48. In addition, the angle formed by the bottom portion 72c and the rotation axis S is set to be larger than the angle formed by the top portion 72a and the rotation axis S. That is, the cam surface 72 is set so that the difference between the radial distance between the top 72a and the rotary shaft S and the radial distance between the bottom 72c and the rotary shaft S increases as the cross section on the front side in the axial direction increases. Has been. That is, the cam surface 72 is set so that the amount of periodic change in the radial distance corresponding to the rotational angle position about the rotational axis S increases as the cross section on the axial front side increases.

  By setting the shape of the cam surface 72 in this way, as the cam member 70 moves relative to the pump member 40, that is, the first rotating member 30 in the axial direction relative to the rear side, From the position of the piston 44 when the rolling element 45 is in contact with the bottom part 72c to the position of the piston 44 when the rolling element 45 is in contact with the top part 72a The amount of movement increases. That is, as the cam member 70 moves rearward in the axial direction, the amount of oil sucked into the hydraulic chamber 46 of the pump member 40 from the suction passage 52 of the passage switching unit 50, that is, from the hydraulic chamber 46 to the discharge passage 56. As a result, the amount of oil discharged increases.

  Further, as shown in FIGS. 2 and 4, the power transmission device 10 extends in the radial direction of the rotation axis S at the front end portion 27 of the second rotation member 20, and is adjacent to the suction passages 92 and 93. Also extending in the radial direction, adjacent discharge passages 95 and 97 are provided. A communication hole 62 is formed in the wall 61 constituting the cam member 70 side (that is, the rear side) of the front end portion 27, and the suction passage 92 is connected to a cam flange described later via the communication hole 62. It communicates with a volume chamber on the 80 side (hereinafter referred to as a cam flange side volume chamber) 91. Further, a communication hole 68 is formed in the wall body 67 constituting the cam member 70 in the front end portion 27, and the discharge passage 97 communicates with the cam flange side volume chamber 98 through the communication hole 68. is doing. The cam flange side volume chamber 91 and the cam flange side volume chamber 98 communicate with each other.

  Further, at the front end portion 27, a wall body 63 is provided inside the wall body 61 in the radial direction, and a wall body 65 is provided inside the wall body 67 in the radial direction. A communication hole 66 is formed in the wall 65, and the communication hole 66 communicates the discharge passage 95 and a volume chamber (hereinafter referred to as a resonance volume chamber) 96 closer to the cam member 70 than the wall 65. ing. The resonance volume chamber 96 is surrounded by a cam flange 80, which will be described later, a passage switching unit 50, and a wall body 65, and communicates with the discharge passage 95 through the communication hole 66. Therefore, the resonance volume chamber 96 functions as an accumulator. It is possible to reduce oil pulsation.

  As shown in FIGS. 2 and 4, a cam flange 80 is coupled to the front end 27 side of the cam member 70 described above. The base 81 of the cam flange 80 is coupled to the front end surface 76 of the cam member 70. The base 81 is configured to surround the outer wall of the above-described passage switching unit 50. From the base portion 81 of the cam flange 80, a projecting portion 82 is provided that forms an annular shape around the rotation axis S and projects the axial direction to the front side. The protruding portion 82 is inserted between the wall body 65 and the wall body 67 and between the wall body 61 and the wall body 63 in the front end portion 27. Further, the cam flange 80 is provided with a tip 83 that protrudes further from the protrusion 82 toward the front side in the axial direction and is inserted into an annular groove 27 c that is dug into the front end 27 in the axial direction. ing. The tip 83 can slide (displace) in the axial direction in the groove 27c. The distal end portion 83 is set to have a smaller radial width of the rotation shaft S than the protruding portion 82. A suction side orifice hole 84 and a discharge side orifice hole 86, which will be described later, are formed between the distal end portion 83 and the protruding portion 82.

  A volume chamber 99 (hereinafter referred to as a rear end side volume chamber) 99 from the cam flange 80 includes a communication hole 78 formed in the cam member 70 and a communication hole formed in the cam flange 80. 87, the discharge passages (56, 57, 58, 95, 97) and the suction passages (92, 93, 54, 53, 52) are communicated with each other via the cam flange side volume chambers 91, 98. . As the cam flange 80 and the cam member 70 slide rearward in the axial direction with respect to the second rotating member 20, the volume of the rear end side volume chamber 99 decreases, and the cam flange side volume chambers 91, 98, and The volume of the resonance volume chamber 96 increases. The oil in the rear end side volume chamber 99 flows from the communication hole 78 and the communication hole 87 to the cam flange side volume chamber 91.

  In addition, as shown in FIGS. 1 and 2, the rear end side volume chamber 99 houses a return spring 88 that is a biasing member that biases the cam flange 80 and the cam member 70 toward the front side in the axial direction. Yes. The return spring 88 is provided between the rear end surface 74 of the cam member 70 and the front end surface 23c of the rear end portion 23. The cam flange 80 and the cam member 70 are urged to the front side, and the front end portion 83 of the cam flange 80 is pressed against the groove 27 c of the front end portion 27.

  The rear end side volume chamber 99 configured as described above can be easily changed in volume by minute expansion and contraction of the return spring 88. Due to this volume change, the rear end side volume chamber 99 easily absorbs pressure fluctuations generated in the discharge passages (56, 57, 58, 95, 97) by the oil discharged intermittently from the pump member 40. It is possible.

  The biasing force by which the return spring 88 biases the cam member 70 toward the front side in the axial direction is referred to as “return biasing force” in the following description. When there is no difference in rotational speed between the first rotating member 30 and the second rotating member 20, the return urging force is generated between the rolling element 45 and the cam surface 72 by the urging force radially outward of the piston spring 43. The pump member 40 acting in between is set larger than the thrust force that urges the cam member 70 toward the axial rear side. The cam member 70 and the cam flange 80 are urged toward the front end 27 by the return urging force, and can be positioned as far as possible on the front side as much as possible in terms of the structure of the cam flange 80 and the front end 27. This position is referred to as “initial position” in the following description.

  A rotational speed difference is generated between the first rotating member 30 and the second rotating member 20, and the thrust force acting on the axial rear side between the rolling element 45 and the cam surface 72 is increased, and the return spring 88. Thus, the cam member 70 is relatively displaced from the initial position to the axial rear side against the return biasing force acting on the axial front side.

  Between the distal end portion 83 and the projecting portion 82 of the cam flange 80, a suction side orifice hole 84 that allows the adjacent suction passage 92 and the suction passage 93 to communicate with each other, and a discharge that causes the adjacent discharge passage 95 and the discharge passage 97 to communicate with each other. A side orifice hole 86 is formed. That is, the cam flange 80 flows in the middle of the suction passages (92, 93, 54, 53, 52), specifically, between the adjacent suction passages 92 and 93 so that the flow passage cross-sectional area becomes small. It has a suction side orifice part (82, 83, 84) capable of narrowing the path. Similarly, the cam flange 80 has a flow passage cross-sectional area that is small in the middle of the discharge passages (56, 57, 58, 95, 97), specifically between the discharge passages 95 and 97 adjacent to each other. It has a discharge side orifice part (82, 83, 86) capable of restricting the flow path.

  The discharge-side orifice portion (82, 83, 86) discharges as the cam flange 80 and the cam member 70 displace the axial direction of the rotation shaft S toward the rear side with respect to the second rotation member 20 from the initial position described above. The flow passage cross-sectional area between the passage 95 and the discharge passage 97 is configured to be reduced (the flow passage is narrowed), and the flow passage resistance around the discharge-side orifice hole 86 is increased. On the other hand, the suction side orifice portions (82, 83, 84) are connected to the suction passage 92 and the suction passage as the cam flange 80 and the cam member 70 are displaced axially rearward with respect to the second rotation member 20 from the initial position. The flow passage cross-sectional area between the passage 93 and the passage 93 is increased (the flow passage is opened), and the flow passage resistance around the suction side orifice hole 84 is reduced.

  That is, at the initial position described above, the flow path is most open between the discharge passage 95 and the discharge passage 97, and the flow passage resistance generated around the discharge-side orifice hole 86 is the smallest. In the stroke of discharging oil, the hydraulic pressure received by the piston 44 is the lowest, that is, the oil is most easily discharged. In the initial position, the flow path is most narrowed between the suction passage 92 and the suction passage 93, and the flow path resistance generated around the suction side orifice hole 84 is the largest. It is difficult to inhale oil.

  Here, a detailed structure near the discharge-side orifice hole 86 provided between the discharge passages 95 and 97 will be described with reference to FIG. In the cam flange 80, the distal end portion 83 is set to have a smaller radial width than the projecting portion 82, and therefore the inner wall on the projecting portion 82 side of the inner wall forming the discharge-side orifice hole 86 is the distal end portion. In addition to the inner wall 82c facing the inner wall 83c on the 83 side, an inner wall 82a is provided. In other words, in the discharge-side orifice hole 86, the inner wall (82a, 82c) on the projecting portion 82 side, that is, the axial rear side is configured to have a larger area than the inner wall 83c on the distal end portion 83 side, that is, the axial front side. Yes. With this configuration, when hydraulic pressure is applied to the discharge passages 95 and 97, an equal force is applied to the inner wall 82c and the inner wall 83c of the discharge-side orifice hole 86 as shown by the arrow Fx in the drawing. Further, a force indicated by an arrow Fy in the drawing can be applied to the inner wall 82a on the protruding portion 82 side of the discharge-side orifice hole 86, and the cam flange 80 is urged toward the rear side in the axial direction of the rotating shaft S. be able to.

  The power transmission device 10 configured as described above includes the pump member 40 that rotates together with the first rotation member 30 and the second rotation member when there is no difference in rotation speed between the first rotation member 30 and the second rotation member 20. The cam member 70 that rotates together with the rotating member 20 does not rotate relatively. That is, the rolling element 45 and the cam surface 72 of the pump member 40 are not relatively rotationally displaced about the rotation axis S, and the pump member 40 does not suck or discharge oil from the passage switching unit 50. .

  In this case, the rolling element 45 of the pump member 40 is positioned closest to the end face 74 with respect to the cam surface 72, and the radial distance between the rolling element 45 and the rotation shaft S is the smallest. In addition, at the initial position, the cam surface 72 is configured such that the difference between the radial distance between the top 72a and the rotation shaft S and the radial distance between the bottom 72c and the rotation shaft S is the smallest. . In other words, the stroke in which the piston 44 reciprocates within the cylinder 41 is configured to be the smallest.

  From such a state, when a rotational speed difference occurs between the first rotating member 30 and the second rotating member 20 and the pump member 40 rotates relative to the cam member 70, the cam surface 72 moves along the cam surface 72. The rolling element 45 and the piston 44 holding it are driven, and the piston 44 reciprocates in the cylinder 41 to reduce / increase the volume of the hydraulic chamber 46. Specifically, when the rolling element 45 and the piston 44 are driven from the top portion 72a toward the bottom portion 72c, the piston 44 moves radially outward in the cylinder 41, and the volume of the hydraulic chamber 46 increases. Takes the oil from the suction passage 52 of the passage switching section 50 into the hydraulic chamber 46. On the other hand, when the rolling element 45 and the piston 44 are driven from the bottom 72c of the cam surface 72 toward the top 72a, the piston 44 moves radially inward in the cylinder 41, and the volume of the hydraulic chamber 46 is reduced. The chamber 46 discharges oil toward the discharge passage 56 of the passage switching unit 50. Thus, the pump member 40 that rotates together with the first rotating member 30 increases the volume of the hydraulic chamber 46 by the piston 44 reciprocating in the cylinder 41 following the cam surface 72 of the cam member 72. The oil from the suction passage 52 of the passage switching unit 50 of the second rotating member 20 is pressure-fed to the discharge passage 56 by decreasing the pressure.

  Thus, the oil in the cam flange side volume chamber 91 flows into the suction passage 52 via the communication hole 62, the suction passage 92, the suction side orifice hole 84, the suction passage 93, the circumferential groove 54, and the communication hole 53, and is supplied to the pump member. 40 is pumped from the suction passage 52 to the discharge passage 56. The oil pressure-fed to the discharge passage 56 flows into the cam flange side volume chamber 98 through the communication hole 57, the circumferential groove 58, the discharge passage 95, the discharge side orifice hole 86, the discharge passage 97, and the communication hole 68. It returns to the cam flange side volume chamber 91 which communicates. Thus, when the pump member 40 that rotates together with the first rotating member 30 and the cam member 70 that rotates together with the second rotating member 20 rotate relatively, the passage switching unit 50 and the pump member 40 of the second rotating member 20 are rotated. Oil is exchanged between the pump member 40 and the pump member 40 pumps the oil, and the oil circulates in the second rotating member 20.

  As described above, when there is a rotational speed difference between the first rotating member 30 and the second rotating member 20, the pump member 40 receives the hydraulic pressure in the stroke in which the piston 44 discharges the oil to the discharge passage 56, and rotates. Between the moving body 45 and the cam surface 72 of the cam member 70, the force by which the rolling body 45 presses the cam surface 72 to the radial direction outer side of the rotating shaft S increases. Due to the increase in the force, a force (hereinafter, referred to as a force for engaging the pump member 40 and the cam member 70 in the circumferential direction of the rotation shaft S between the rolling element 45 of the pump member 40 and the cam surface 72 of the cam member 70). (Denoted as engaging force). Due to this engaging force, torque acts between the first rotating member 30 and the second rotating member 20 via the pump member 40 and the cam member 70.

  In addition, a thrust force is generated, which is a force by which the rolling element 45 of the pump member 40 urges the cam surface 72 of the cam member 70 toward the axial rear side. Thus, the thrust force acting between the pump member 40 and the cam member 70 resists the return urging force of the return spring 88 and relatively displaces the cam member 70 from the initial position to the axial rear side. . When the cam member 70 is relatively displaced toward the rear side in the axial direction, the radial distance between the contact point between the cam surface 72 and the rolling element 45 and the rotary shaft S increases, and the stroke of the piston 44 increases. Thus, the amount of oil discharged from the hydraulic chamber 46 to the discharge passage 56 and the amount of oil sucked into the hydraulic chamber 46 from the suction passage 52 when the pump member 40 makes one rotation relative to the cam member 70. Will increase. That is, the flow rate of oil circulating in the second rotating member 20 increases.

  In addition, since the cam flange 80 coupled to the cam member 70 is displaced to the rear side in the axial direction, the suction side orifice hole 84 and the discharge side orifice hole 86 are moved to the rear side in the axial direction. The flow path between the suction passage 93 and the suction passage 93 is opened, the flow resistance at the suction passages 92 and 93 is reduced, and the flow path between the discharge passage 95 and the discharge passage 97 is narrowed down. The flow path resistance at 97 increases.

  Thereby, although the pump member 40 can suck oil relatively well from the suction passage 52 into the hydraulic chamber 46, the flow resistance in the discharge passages 95 and 97 increases, so that the hydraulic pressure in the discharge passage 56 increases. The piston 44 is difficult to discharge oil from the hydraulic chamber 46. That is, in the stroke in which the piston 44 discharges oil, the hydraulic pressure received by the piston 44 increases.

  Thus, in the pump member 40, the oil pressure received by the piston 44 in the stroke of discharging the oil increases, so that the diameter of the rotating shaft S is between the rolling element 45 held by the piston 44 and the cam surface 72. The force acting outward in the direction further increases, and the thrust force that displaces the cam member 70 toward the rear side in the axial direction and the engaging force that acts in the circumferential direction of the rotating shaft S further increase. In this way, as the rotational speed difference between the first rotating member 30 and the second rotating member 20 increases, the first rotating member 30 and the second rotating member 20 are engaged in the circumferential direction of the rotating shaft S. By increasing the engagement force to be combined, the torque transmitted between the first rotating member 30 and the second rotating member 20 can be quickly increased without using external power.

  As described above, the power transmission device 10 according to this embodiment includes the first rotating member 30 (31, 32, 34) and the second rotating member 20 (21, 21) that are relatively rotatable about the rotation axis S. 22, 23, 25, 27) and the inner side in the radial direction of the rotation axis S, the radial distance from the rotation axis S changes according to the rotation angle position around the rotation axis S. The cam surface 72 is set so that the radial distance and the amount of change in the radial direction increase toward the one side (front side) in the axial direction. The cam member 70 is provided so as to be displaceable and rotates around the rotation axis S together with the second rotation member 20, and rotates around the rotation axis S together with the first rotation member 30, and the piston 44 is driven by the cam surface 72. Thus, the cylinder 41 reciprocates in the radial direction of the rotation axis S. Thus, oil is sucked into the cylinder 41 from the suction passage 52 provided in the passage switching portion 50 of the second rotating member 20, and the oil is discharged into the discharge passage 56 provided in the passage switching portion 50 of the second rotating member 20. The pump member 40 capable of circulating oil in the second rotating member 20 and the biasing member that biases the cam member 70 toward the one side (front side) with respect to the second rotating member 20. It has a return spring 88 as a member.

  As the rotational speed difference between the first rotating member 30 and the second rotating member 20 increases, the force with which the pump member 40 presses the cam member 70 radially outward of the rotating shaft S increases, and the pump member 40 and the cam member The torque transmitted between the first rotating member 30 and the second rotating member 20 can be increased by increasing the engagement force with which the rotating shaft S is engaged in the circumferential direction of the rotating shaft S. The thrust force generated according to the force by which the pump member 40 presses the cam member 70 radially outward causes the return biasing force that the return spring 88 as the biasing member biases the cam member 70 toward the one side (front side). Against this, the cam member 70 is displaced to the other side (rear side), thereby increasing the stroke of the piston 44 and increasing the flow rate of oil circulated by the pump member 40, thereby discharging the oil. The hydraulic pressure received by the piston 44 in the stroke is increased. As a result, the engagement force and the thrust force acting between the pump member 40 and the cam member 70 are further increased, and the torque transmitted between the first rotating member 30 and the second rotating member 20 is reduced to the external power. It can be increased quickly without use.

  Further, in the power transmission device 10 according to the present embodiment, the second rotation member 20 is provided on the one side (front side) with respect to the pump member 40, and the suction passage 52 is connected to the end surface 55 on the pump member 40 side. A passage switching unit 50 in which the discharge passages 56 are alternately arranged in the circumferential direction of the rotation axis S, the pump member 40 abuts on the end surface 55 and the suction passage 52 or the discharge passage 56 communicates with the cylinder 41 is provided. It was supposed to have. The pump member 40 that rotates together with the first rotating member 30 receives the urging force of the above-described urging member (return spring 88) via the cam member 70 and is urged to one side (front side). It is pressed against the end surface 55 of the oil passage switching unit 50 provided on one side (front side) of the member 40. For this reason, the pump member 40 suppresses oil from leaking between the suction passage 52 and the discharge passage 56 provided in the oil passage switching unit 50, and exchanges the oil with the second rotating member 20. It is possible to suppress the hydraulic pressure in the cylinder 41 from decreasing.

  Further, in the power transmission device 10 according to the present embodiment, as the cam member 70 is displaced to the other side (rear side), the cross-sectional area of the flow path is in the middle of the discharge passage (56, 57, 58, 95, 97). It has a discharge side orifice part (82, 83, 86) to reduce the size. As the rotational speed difference between the first rotating member 30 and the second rotating member 20 increases, the flow path resistance in the discharge passage (56, 57, 58, 95, 97) is increased, and the piston is discharged in the stroke of discharging oil. The hydraulic pressure received by the shaft 44 can be increased, and the force with which the pump member 40 presses the cam member 70 radially outward of the rotation shaft S can be increased. Thus, the engagement force acting in the circumferential direction of the rotation shaft S between the pump member 40 and the cam member 70, that is, the torque transmitted between the first rotation member 30 and the second rotation member 20 is increased. Can do.

  Further, in the power transmission device 10 according to the present embodiment, the cross-sectional area of the flow path in the middle of the suction passage (92, 93, 54, 53, 52) as it is positioned on the one side (front side) together with the cam member 70. It has an inlet side orifice part (82, 83, 84) for reducing the size. When the difference in rotational speed between the first rotating member 30 and the second rotating member 20 is small and the cam member 70 is located on the one side (front side), the pump member 40 hardly sucks oil, and the pump The engagement force acting in the circumferential direction of the rotation shaft S between the member 40 and the cam member 70 can be reduced.

  Further, in the power transmission device 10 according to the present embodiment, the inner walls (82a, 82c) of the discharge-side orifice hole 86 that communicates the adjacent discharge passages (95, 97) among the discharge-side orifice portions (82, 83, 86). 83c) is configured such that the inner wall (82a, 82c) on the other side has a larger area than the inner wall 83c on the one side. When hydraulic pressure is applied to the discharge passages (95, 97), the inner wall (82a, 82c) on the other side (rear side) of the discharge side orifice hole 86 is larger than the inner wall 83c on the one side. A force can be applied, and the cam member 70 can be biased (pressed) toward the other side (rear side) of the rotation shaft S in the axial direction.

  In the power transmission device 10 according to the present embodiment, the discharge passage (56, 57, 58, 95, 97) communicates with the discharge passage (56, 57, 58, 95, 97) and houses a return spring 88 as an urging member. , 57, 58, 95, 97), the rear end side volume chamber 99 capable of reducing the pressure pulsation is provided. The rear end side volume chamber 99 can be easily changed in volume by minute expansion and contraction of the urging member (return spring 88), and the oil discharged intermittently from the pump member 40 can be used. Pressure fluctuations generated in the discharge passages (56, 57, 58, 95, 97) can be easily absorbed.

  Further, in the power transmission device 10 according to the present embodiment, the pump member 40 includes a piston spring 43 that biases the piston 44 radially outward of the rotation shaft S, and the first rotation member 30 and the second rotation member. When there is no rotational speed difference with respect to 20, the return urging force that the return spring 88 as the urging member urges the cam member 70 toward the one side (front side) is pumped by the urging force of the piston spring 43. The thrust force applied from the member 40 to the cam member 70 is set larger than the thrust force acting on the other side (rear side). When there is no rotational speed difference between the first rotating member 30 and the second rotating member 20, the cam member 70 is located on the most possible side (front side) as far as possible with respect to the second rotating member 20 in terms of structure. The stroke of the piston 44 can be minimized at the position.

  As described above, the present invention is suitable for a power transmission device with a differential limiting function, and in particular, has a first rotating member and a second rotating member that are relatively rotatable about a rotating shaft, This is useful for a power transmission device that increases the torque transmitted between the first rotating member and the second rotating member as the rotational speed difference between the first rotating member and the second rotating member increases.

It is sectional drawing of the power transmission device which concerns on this embodiment, and the differential gear connected to this. It is an expanded sectional view of the power transmission device concerning this embodiment, and is a sectional view by the AA line of FIG. It is sectional drawing by the BB line of FIG.1 and FIG.2. It is sectional drawing by CC line of FIG.1 and FIG.2. It is sectional drawing which shows the periphery of the discharge side orifice hole provided in the middle of the discharge channel.

Explanation of symbols

3 Propulsion shaft 6 Differential device 8a, 8c Drive shaft 9 Ring gear 10 Power transmission device 20 Second rotating member 21 Drive pinion 23 Rear end (second rotating member)
25 Cylindrical part (second rotating member)
27 Front end (second rotating member)
30 First rotating member 31 Flange (first rotating member)
32 Large diameter part (first rotating member)
34 Small diameter part (first rotating member)
40 Pump member 41 Pump member cylinder 44 Pump member piston 45 Pump member rolling element 50 Passage switching portion (second rotating member)
70 Cam member 72 Cam surface 80 Cam flange 88 Return spring

Claims (7)

A first rotating member and a second rotating member that are relatively rotatable about a rotation axis;
The radial distance from the rotation axis faces the inside in the radial direction, and the radial distance from the rotation axis changes according to the rotation angle position around the rotation axis. A cam member having a cam surface set so that the amount of change is large, provided so as to be displaceable in the axial direction of the rotary shaft with respect to the second rotary member, and rotating around the rotary shaft together with the second rotary member When,
The oil rotates from the suction passage provided in the second rotating member by rotating around the rotating shaft together with the first rotating member and reciprocating in the cylinder in the radial direction of the rotating shaft by the piston following the cam surface. A pump member capable of sucking into the cylinder, discharging the oil to a discharge passage provided in the second rotating member, and circulating the oil in the second rotating member;
A biasing member that biases the cam member toward the one side with respect to the second rotating member;
A power transmission device comprising: The power transmission device according to claim 1,
The second rotating member is
Provided on the one side with respect to the pump member, the suction passages and the discharge passages are alternately arranged in the circumferential direction of the rotating shaft on the end surface on the pump member side, and the pump member abuts on the end surface so that the suction passage or The power transmission device, wherein the discharge passage has a passage switching portion communicating with the cylinder. In the power transmission device according to claim 1 or 2,
A power transmission apparatus comprising: a discharge-side orifice portion that reduces a flow passage cross-sectional area in the middle of the discharge passage as it is displaced together with the cam member in the axial direction of the rotation shaft. In the power transmission device according to any one of claims 1 to 3,
A power transmission device comprising a suction-side orifice portion that reduces a cross-sectional area in the middle of the suction passage as it is positioned on the one side together with the cam member. In the power transmission device according to claim 3,
Of the discharge side orifice portion, the inner wall of the discharge side orifice hole for communicating adjacent discharge passages is configured such that the inner wall on the other side has a larger area than the inner wall on the one side. Power transmission device. The power transmission device according to claim 4,
A power transmission device characterized in that a volume chamber is provided which communicates with the discharge passage and accommodates the urging member to reduce pressure fluctuations in the discharge passage. In the power transmission device according to any one of claims 1 to 6,
The pump member has a piston spring that biases the piston outward in the radial direction of the rotating shaft,
When there is no rotational speed difference between the first rotating member and the second rotating member, the biasing force by which the biasing member biases the cam member toward the one side is from the pump member to the cam member by the biasing force of the piston spring. The power transmission device is characterized in that it is set larger than the thrust force acting on the other side.

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