WO1999006726A1 - Three-dimensional power transmission device - Google Patents

Three-dimensional power transmission device Download PDF

Info

Publication number
WO1999006726A1
WO1999006726A1 PCT/KR1998/000223 KR9800223W WO9906726A1 WO 1999006726 A1 WO1999006726 A1 WO 1999006726A1 KR 9800223 W KR9800223 W KR 9800223W WO 9906726 A1 WO9906726 A1 WO 9906726A1
Authority
WO
WIPO (PCT)
Prior art keywords
drive
yoke
driven
bevel gear
angle
Prior art date
Application number
PCT/KR1998/000223
Other languages
French (fr)
Inventor
Sung Nam Hong
Original Assignee
Sung Nam Hong
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sung Nam Hong filed Critical Sung Nam Hong
Publication of WO1999006726A1 publication Critical patent/WO1999006726A1/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D3/00—Yielding couplings, i.e. with means permitting movement between the connected parts during the drive
    • F16D3/16—Universal joints in which flexibility is produced by means of pivots or sliding or rolling connecting parts
    • F16D3/26—Hooke's joints or other joints with an equivalent intermediate member to which each coupling part is pivotally or slidably connected
    • F16D3/30—Hooke's joints or other joints with an equivalent intermediate member to which each coupling part is pivotally or slidably connected in which the coupling is specially adapted to constant velocity-ratio
    • F16D3/32—Hooke's joints or other joints with an equivalent intermediate member to which each coupling part is pivotally or slidably connected in which the coupling is specially adapted to constant velocity-ratio by the provision of two intermediate members each having two relatively perpendicular trunnions or bearings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D3/00—Yielding couplings, i.e. with means permitting movement between the connected parts during the drive
    • F16D3/50—Yielding couplings, i.e. with means permitting movement between the connected parts during the drive with the coupling parts connected by one or more intermediate members

Definitions

  • the present invention relates to, in general, a power transmission device, and more particularly, to a three- dimensional power transmission device capable of transmitting the rotating force of a drive shaft to a driven shaft while allowing the driven shaft to be rotated at the same rotating angle and in the same direction as the drive shaft being rotatable at an angle ⁇ of 0° ⁇ ⁇ ⁇ 90° in any direction.
  • a power transmission device or mechanism such as an universal joint member, is used for transmitting the rotating force of a drive shaft to a driven shaft regardless of the angle between the drive and driven shafts.
  • the typical power transmission device demands two or three typical universal joints or an additional transmission device, thus complicating the construction, enlarging the volume and size and increasing the weight of the device.
  • a transmission device is problematic in that it fails to be effectively used in industrial fields such as the robotics industry and space engineering, etc. being in need of an essential power transmission mechanism.
  • a multi-angle axis proposed by the inventors of this invention, is disclosed in Korean Patent Publication Nos. 89-1513 and 91- 951.
  • the angle between the drive and driven shafts is an acute angle of 0° ⁇ a ⁇ 90°
  • the rotating force of the drive shaft is effectively transmitted to the driven shaft by the multi-angle axis without requiring any combination of power transmission devices or an additional transmission device.
  • Such a multi-angle axis comprises a pair of semi-circular drive ring members, slidably connected to the end portions of drive and driven shafts, and small or large gears.
  • the gears are mounted to the end portions of the drive ring members.
  • the multi-angle axis further comprises connection pins mounted to the end portions of the semi-circular drive ring members by pivot pins. The connection pins, inserted into rotatable central rings, are slid and rotated along the inner surface of the central rings.
  • the above multi-angle axis has problems in that semi-circular holes are formed on the drive and driven shafts because the semi-circular drive ring members are inserted into the semi-circular holes of the drive and driven shafts. Also, the contact portions between the drive ring members and holes are easily abraded due to the sliding motion of the drive ring members, thereby causing the drive ring members to be broken.
  • a power transmission device proposed by the inventors of this invention, is disclosed in Korean Utility Model Publication No. 95-6376. Such a device includes a pair of transmission gears and small gears.
  • the above transmission device demands lubricant for reducing the operational noises caused from the engaging junction of the gears. Also, the engaging teeth of the gears may be easily abraded by the load acting on the engaging teeth.
  • the power transmission device of Korean Patent Application No. 95-12923 is capable of transmitting the rotating force of a drive shaft to a driven shaft while allowing the driven shaft to be rotated at the same rotating angle and in the same direction as the drive shaft being rotatable at an angle a of 0° ⁇ a ⁇ 90° in any direction, thereby reducing the operational noises and load of the device.
  • the above device comprises a plurality of parts and drive ring members consisting of bearings and so it is difficult to produce the device.
  • the drive shaft may fail to completely or correctly transmit its rotating force to the driven shaft after the device has been used for a long time,
  • an object of the present invention is to provide a three- dimensional power transmission device capable of transmitting the rotating force of a drive shaft to a driven shaft while allowing the driven shaft to be rotated at the same rotating angle and in the same direction as the drive shaft being rotatable at an angle ⁇ of 0° ⁇ ⁇ ⁇ 90° in any direction.
  • the present invention provides a three-dimensional power transmission device, comprising: a drive yoke fixedly connected to a drive shaft; a driven yoke fixedly connected to a driven shaft; a middle yoke hinged to both the drive and driven yokes, thus universally transmitting the rotating force of the drive shaft to the driven shaft, the middle yoke having two yoke parts at its opposite ends; and first and second joint units universally connecting the two yoke parts of the middle yoke to the drive and driven yokes respectively, the two joint units transmitting the rotating force of the drive shaft to the driven shaft through the three yokes while allowing the drive and driven yokes, with the drive and driven shafts, to be rotated around the first and second joint units at the same rotating angle and in the same direction as said drive yoke being rotatable around the first joint unit at an angle ⁇ of 0° ⁇ ⁇ ⁇ 90° in any direction.
  • the first and second joint units have the same construction, each of the two joint units comprising a cross member with both a vertical part of the cross member being hinged to the drive or driven yoke and a horizontal part of the cross member being hinged to each of the two yoke parts of the middle yoke.
  • the three-dimensional power transmission device further comprises a first bevel gear fitted over the top end of the vertical part of the cross member; a balance ring fitted over the bottom end of the vertical part; a second bevel gear fitted over one end of the horizontal part of the cross member, the second bevel gear engaging with said first bevel gear and having a belt groove on its outer surface; a pulley fitted over the other end of the horizontal part, the pulley having a belt groove on its outer surface; and a needle bearing provided on each end of the vertical and horizontal parts of the cross member, thus rotatably holding the cross member at each bearing seat of the drive, driven and middle yokes .
  • Fig. 1 is a schematic perspective view of a three- dimensional power transmission device in accordance with the preferred embodiment the present invention
  • Fig. 2 is an exploded perspective view of the power transmission device according to the embodiment of the present invention.
  • Fig. 3 is a perspective view showing the essential parts of the power transmission device according to the embodiment of the present invention
  • Fig. 4 is a top view showing the power transmission device according to the embodiment of this invention
  • Fig. 5 is a side view of the power transmission device according to the embodiment of this invention.
  • Fig. 6 is a sectional view of the power transmission device taken along the line A-A of Fig. 5;
  • Fig. 7 is a sectional view of the power transmission device taken along the line B-B of Fig. 4;
  • Fig. 8 is a sectional view of the power transmission device taken along the line C-C of Fig. 4;
  • Fig. 9 is a view illustrating the drive shaft of Fig. 6, which is rotated and maintained at an angle ⁇ of 0° ⁇ ⁇ ⁇ 45°;
  • Fig. 10 is a view illustrating the power transmission device rotated from the position of Fig. 9;
  • Fig. 11 is a view illustrating the drive shaft of Fig. 8, which is rotated and maintained at an angle ⁇ of 0° ⁇ ⁇ ⁇ 45°;
  • Fig. 12 is a view illustrating the power transmission device rotated from the position of Fig. 11;
  • a three-dimension power transmission device comprises a drive yoke 11 fixedly connected to a drive shaft 1, a driven yoke 12 fixedly connected to a driven shaft 2, and a middle yoke 3 hinged to both the drive and driven yokes 1 and 2.
  • the middle yoke 3 has two yoke parts at its opposite ends, while first and second joint units 100 and 200 universally connect the two yoke parts of the middle yoke 3 to the drive and driven yokes 11 and 12, respectively.
  • the first and second joint units 100 and 200 have the same construction and are mounted to shafts 1 and 2 in the same manner, but the first joint unit 100 is fixedly mounted to the drive shaft 1, while the second joint unit 200 is fixedly mounted to the driven shaft 2.
  • the first joint unit 100 is connected to both the drive yoke 11 and the middle yoke 3, while the second joint unit 200 is connected to both the middle yoke 3 and the driven yoke 12.
  • the first joint unit 100 comprises a first cross member 101 with vertical and horizontal parts. That is, top and bottom ends of the vertical part of the member 101 are respectively hinged to the two yoke parts 103 and 109 of the drive yoke 11, while both ends of the horizontal part of the member 101 are respectively hinged to the two yoke parts 107 and 112 of the middle yoke 3.
  • a first bevel gear 102 is fitted over the top portion 101-1 of the vertical part of the first cross member 101, while a balance ring 108 is fitted over the bottom portion 101-3 of the vertical part.
  • a second bevel gear 106 having a pair of belt grooves 105 on its outer surface, is fitted over one end portion 101-2 of the horizontal part of the first cross member 101 and engages with the first bevel gear 102.
  • a pulley 111 having a pair of belt grooves 110 on its outer surface, is fitted over the other end portion 101-4 of the horizontal part of the cross member 101.
  • a plurality of needle bearings 104 and snap rings 6 are provided on each end of the vertical and horizontal parts of the cross member 101, thereby rotatably holding the cross member 101 at each bearing seat of the drive and middle yokes 11 and 3.
  • the second joint unit 200 comprises a second cross member 201 with vertical and horizontal parts. That is, top and bottom ends of the vertical part of the member 201 are respectively hinged to the two yoke parts 203 and 209 of the driven yoke 12, while both ends of the horizontal part of the member 201 are respectively hinged to the two yoke parts 207 and 212 of the middle yoke 3.
  • a first bevel gear 202 is fitted over the top portion 201-1 of the vertical part of the member 201, while a balance ring 208 is fitted over the bottom portion 201-3 of the vertical part.
  • a second bevel gear 206 having a pair of belt grooves 205 on its outer surface, is fitted over one end portion 201-2 of the horizontal part of the second cross member 201 and engages with the first bevel gear 202.
  • a pulley 211 having a pair of belt grooves 210 on its outer surface, is fitted over the other end portion 201-4 of the horizontal part of the second cross member 201.
  • a plurality of needle bearings 104 and snap rings 6 are provided on each end of the vertical and horizontal parts of the cross member 201, thereby rotatably holding the cross member 201 at each bearing seat of the driven and middle yokes 12 and 3.
  • the two second bevel gears 106 and 206 of the first and second joint units 100 and 200 are connected to each other through an endless belt 4 in such a manner that the belt 4 wraps around and intersects between the two second bevel gears 106 and 206.
  • the two pulleys 111 and 211 of the first and second joint units 100 and 200 are connected to each other through an endless belt 5 in such a manner that the belt 5 wraps around and intersects between the two pulleys 111 and 211.
  • a fitting member 9 is fixedly mounted to each of the two first bevel gears 102 and 202, two second bevel gears 106 and 206, two balance wheels 108 and 208, and two pulleys 111 and 211.
  • Such a fitting member 9, having a screw hole 8 is fitted in the mouth of each bearing seat of the drive, driven and middle yokes 11, 12 and 3 in such a manner that the member 9 is fixed at its place in each bearing seat by a set bolt 7 passing through the screw hole 8.
  • the second joint unit 200 is mounted at the junction between the driven yoke 12 and the middle yoke 3 in the same manner as described for the first joint unit 100, thus accomplishing assemblage of the device of this invention. Also, as shown in Fig. 1, the power transmission device according to this invention is protected by a bellows member 90 surrounding the device.
  • the drive shaft 1 is mounted to a power generating means such as an engine, through a conventional manner.
  • the rotating force of the engine is transmitted to the drive shaft, thus rotating the drive shaft 1.
  • the rotating force of the drive shaft 1 is transmitted to the first joint unit 100 through the drive yoke 11.
  • the first joint unit 100 is rotated with the middle yoke 3.
  • the rotating force of the drive shaft 1 is completely transmitted to the first cross member 101 because the top and bottom ends of the vertical part of the member 101 are hinged to the two yoke parts 103 and 109 of the drive yoke 11.
  • the middle yoke 3 is rotated by the rotating force of the cross member 101 because both ends of the horizontal part of the member 101 are hinged to the two yoke parts 107 and 112 of the middle yoke 3.
  • the driven yoke 12 is rotated by the rotating force of the middle yoke 3 because both ends of the horizontal part of the second cross member 201 are hinged to the two yoke parts 207 and 212 of the middle yoke 3, and the top and bottom ends of the vertical part of the member 201 are hinged to the two yoke parts 203 and 209 of the driven yoke 12. Therefore, the rotating force of the drive shaft 1 is completely transmitted to the driven shaft 2.
  • the first bevel gear 102 of the first joint unit 100 revolves from its top position in the same direction as the rotating direction of the drive shaft 1.
  • the second bevel gear 106 of the first joint unit 100 engaging with the first bevel gear 102, is rotated clockwise or counterclockwise in the drawings at the same rotating angle as the revolving angle of the first bevel gear 102.
  • the second bevel gear 106 thus rotates the belt 4.
  • the rotating length of the belt 4 is influenced by the rotating angle of the second bevel gear 106.
  • the second bevel gear 206 of the second joint unit 200 is rotated.
  • the rotating angle of the bevel gear 206 is equal to that of the other bevel gear 106, while the rotating direction of the bevel gear 206 is opposite that of the other bevel gear 106 since the belt 4 intersects between the two gears 106 and 206.
  • the first bevel gear 202 of the second joint unit 200 engaging with the second bevel gear 206, is revolved at the same angle as the rotating angle of the second bevel gear 206.
  • the driven yoke 12 fixedly mounted to the first gear 202, is upwardly or downwardly rotated by revolving the first gear 202 of the second joint unit 200. Therefore, the driven shaft 2, fixed to the driven yoke 12, is upwardly or downwardly rotated.
  • the rotating angle of the driven shaft 2 is maintained at a same angle ⁇ of 0° ⁇ ⁇ ⁇ 45° as the rotating angle of the drive shaft 1. Therefore, when the rotating angles ⁇ of the drive and driven shafts 1 and 2 are 0° ⁇ ⁇ ⁇ 45°, the angle ⁇ between the drive and driven shafts 1 and 2 is maintained at the angle of 0° ⁇ ⁇ ⁇ 90°.
  • the rotating force of the drive shaft 1 is transmitted to the first joint unit 100 through the drive yoke 11.
  • the first joint unit 100 is rotated with the middle yoke 3.
  • the vertical part of the first cross member 101 is rotated.
  • the vertical part of the member 101 is rotated and revolved because the needle bearings 104, mounted to the top and bottom portion 101-1 and 101-3 of the vertical part of the member 101, are seated in the two yoke parts 103 and 109 of the drive yoke 11.
  • the horizontal part of the first cross member 101 is rotated on its axis by the rotating force of the second bevel gear 106 because the needle bearings 104, mounted to both ends of the horizontal part of the member 101, are seated in the yoke parts 107 and 112 of the middle yoke 3.
  • the rotating force of the vertical part of the cross member 101 is completely transmitted to the horizontal part of the member 101.
  • the middle yoke 3 is rotated by the rotating force of the horizontal part of the cross member 101 because both ends of the horizontal part of the member 101 are hinged to the yoke parts 107 and 112 of the middle yoke 3.
  • the driven yoke 12 is rotated by the middle yoke 3 with the second joint unit 200 jointing the middle yoke
  • the second cross member 201 is rotated because both ends of the horizontal part of the member 201 are hinged to the two yoke parts 207 and 212 of the middle yoke 3, respectively.
  • the two belts 4 and 5 wrapping on both the belt grooves 105 of the second bevel gear 106 and the belt grooves 110 of the pulley 111 are respectively rotated clockwise or counterclockwise by the rotating force of the middle yoke 3.
  • the rotating angle of both the second bevel gear 206 and the pulley 211 is equal to that of the two belts 4 and 5, while the rotating direction of both the second bevel gear 206 and the pulley 211 is opposite that of the two belts 4 and 5.
  • the first bevel gear 202 engaging with the second bevel gear 206 of the second joint unit 200, is revolved at the same rotating angle as the revolving angle of the first bevel gear 206. Due to such a revolution motion of the first bevel gear 202, the driven yoke 12, hinged to the first bevel gear 202, is upwardly or downwardly rotated.
  • the driven shaft 2 fixed to the driven yoke 12 is upwardly or downwardly rotated. Therefore, the driven shaft 2 is rotated and maintained at the same angle as the rotating angle of the drive shaft 1.
  • Fig. 12 is a schematic view illustrating the rotating function of the power transmission device of Fig. 11.
  • the vertical part of the first cross member 101 is rotated at the same angle ⁇ as the rotating angle of the drive shaft 1, while the vertical part is maintained at a vertical position relative to the drive shaft
  • the horizontal part of the cross member 101 is rotated on its axis at the same angle as the rotating angle of the drive shaft 1 in the two yoke parts 107 and 112 of the middle yoke 3.
  • both the second bevel gear 106 and the pulley 111 mounted to both ends of the horizontal part of the first cross member 101, are rotated at the same angle as the rotating angle of the horizontal part of the member 101.
  • both the second bevel gear 206 and pulley 211 of the second joint unit 200 are forcibly rotated by the rotating force of the two belts 4 and 5.
  • the horizontal part of the second cross member 201, with the second bevel gear 206 and the pulley 211 is rotated around the two yoke parts 107 and 112 of the middle yoke 3 by the rotating force of both the second bevel gear 206 and the pulley 211. Due to such a rotating motion of the horizontal part of the cross member 201, the vertical part of the second cross member 201 is shifted around the horizontal part of the member
  • the driven yoke 12 is shifted at the same angle as the rotating angle of the vertical part of the cross member 201, the driven shaft 2 is maintained at the same angle as the rotating angle of the drive shaft 1. Due to such a function, the rotating force of the drive shaft 1 is completely transmitted to the first joint unit 100 through the drive yoke 11. As a result, the first joint unit 100 is rotated with the middle yoke 3.
  • the vertical part of the first cross member 101 is rotated.
  • the vertical part of the member 101 is rotated and revolved because the needle bearings 104, mounted to both the top and bottom portion 101-1 and 101-3 of the vertical part of the member 101, are seated in the two yoke parts 103 and 109 of the drive yoke 11.
  • the horizontal part of the first cross member 101 is rotated on its axis by the rotating force of the second bevel gear 106 because the needle bearings 104, mounted to both ends of the horizontal part of the member 101, are sated in the yoke parts 107 and 112 of the middle yoke 3.
  • the rotating force of the vertical part of the first cross member 101 is completely transmitted to the horizontal part of the member 101.
  • the middle yoke 3 is rotated by the rotating force of the horizontal part of the cross member 101 because both ends of the horizontal part of the member 101 are hinged to the yoke parts 107 and 112 of the middle yoke 3.
  • the driven yoke 12 is rotated by the rotating force of the middle yoke 3. That is, the second cross member 201 is rotated because both ends of the horizontal parts of the member 201 are hinged to the two yoke parts 207 and 212 of the middle yoke 3, respectively.
  • the two belts 4 and 5, wrapping on the belt grooves 105 of the second bevel gear 106 and the belt grooves 110 of the pulley 111, are rotated clockwise or counterclockwise by the rotating force of the middle yoke 3.
  • the rotating angle of both the second bevel gear 206 and the pulley 211 is equal to that of the two belts 4 and 5, while the rotating direction of both the second bevel gear 206 and the pulley 211 is opposite that of the two belts 4 and 5.
  • the first bevel gear 202, engaging with the second bevel gear 206 of the second joint unit 200, is rotated at the same rotating angle as the revolving angle of the first bevel gear 206.
  • the driven yoke 12 hinged to the first bevel gear 202 Due to such a rotating force of the first bevel gear 202, the driven yoke 12, hinged to the first bevel gear 202, is upwardly or downwardly rotated.
  • the driven shaft 2, fixed to the driven yoke 12 is upwardly or downwardly rotated.
  • the drive and driven shafts 1 and 2 are rotated at the rotating angle ⁇ of 0° ⁇ ⁇ ⁇ 45°, respectively.
  • the angle X between the drive and driven shafts 1 and 2 is maintained at the angle of 0° ⁇
  • the angle X between the drive and driven shafts 1 and 2 maintains at an angle of 90° ⁇ X ⁇ 180° as follows.
  • the drive shaft 1 is upwardly or downwardly rotated at an angle ⁇ of 45° ⁇ ⁇ ⁇ 90°
  • the first bevel gear 102 fixed to the drive yoke 11, is revolved in the same direction as the rotating direction of the drive shaft 1.
  • the maximum revolution of the first bevel gear 102 is a quarter revolution. Due to the revolution of the first bevel gear 102 of the first joint unit 100, the second bevel gear 106, engaging with the first bevel gear 102, is rotated clockwise or counterclockwise in the drawings at the same angle as the revolving angle of the first bevel gear 102. Thus, the second bevel gear 106 rotates the belt 4 at the same angle as the revolving angle of the first bevel gear 102. In the above state, when the drive shaft 1 is rotated at the maximum rotating angle ⁇ of 90°, the drive shaft 1 is coaxial with the horizontal part of the first cross member 101.
  • the second bevel gear 206 of the second joint unit 200 is rotated.
  • the rotating angle of the bevel gear 206 is equal to that of the other bevel gear 106, while the rotating direction of the bevel gear 206 is opposite that of the other bevel gear 106 since the belt 4 intersects between the two gears 106 and 206.
  • first bevel gear 202 of the second joint unit 200 engaging with the second bevel gear 206, is rotated at the same angle as the rotating angle of the second bevel gear 206.
  • the driven yoke 12 fixedly mounted to the first gear 202, is upwardly or downwardly rotated by the rotating force of the first gear 202 of the second joint unit 200.
  • the driven shaft 2 fixed to the driven yoke 12 is upwardly or downwardly rotated.
  • the rotating angle of the driven shaft 2 is maintained at the same angle ⁇ of 45° ⁇ ⁇ ⁇ 90° as the rotating angle of the drive shaft 1.
  • the driven shaft 2 when the driven shaft 2 is rotated at the maximum rotating angle ⁇ of 90°, the driven shaft 2 is coaxial with the horizontal part of the first cross member 101. Thus, the driven shaft 2 is parallel to the drive shaft 1 as shown in Fig. 13.
  • Fig. 14 is a view illustrating the quarter rotated state of the drive shaft 1.
  • the horizontal part of the first cross member 101 is maintained at a vertical position relative to the drive shaft 1.
  • both the second bevel gear 106 and the pulley 111 mounted to both ends of the horizontal part of the first cross member 101, are rotated at the same angle as the rotating angle of the horizontal part of the member 101.
  • both the second bevel gear 206 and the pulley 211 of the second joint unit 200 are forcibly rotated by the rotating force of the two belts 4 and 5.
  • the vertical part of the member 201 is shifted around the horizontal part of the member 201 at the same angle as the rotating angle ⁇ of the vertical part of the first cross member 101.
  • the rotating angle of the driven shaft 2 is maintained at the same angle as the rotating angle of the drive shaft 1. That is, the rotating angle ⁇ of the driven shaft 2 is maintained at 45° ⁇ ⁇ ⁇ 90°.
  • the driven shaft 2 is coaxial with the horizontal part of the first cross member 101.
  • the driven shaft 2 is parallel to the drive shaft 1 as shown in Fig. 14. Therefore, when the drive and driven shafts 1 and 2 are rotated at an angle ⁇ of 45° ⁇ ⁇ ⁇ 90°, the angle X between the drive and driven shafts 1 and 2 is maintained at an angle of 90° ⁇ ⁇ ⁇ 180°.
  • the transmission process of the rotating force of the drive shaft 1 is similar to the process of Figs. 9 to 12, where the half rotation of the drive shaft 1 is performed at the rotation angle ⁇ of 45° ⁇ ⁇ ⁇ 90° or at the angle of 90° ⁇ X ⁇ 180° .
  • the three-dimensional power transmission device of this invention comprises first and second joint units for completely transmitting the rotating force of the drive shaft to the driven shaft while allowing the driven shaft to be rotated around the first and second joint units at the same rotating angle and in the same direction as the drive shaft being rotatable around the first joint unit at an angle ⁇ of 0° ⁇ ⁇ ⁇ 90° in any direction.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Gear Transmission (AREA)
  • Transmission Devices (AREA)

Abstract

A three-dimensional power transmission device is disclosed. The device has drive and driven yokes (11, 12) connected to drive and driven shafts (1, 2) and a middle yoke (3) hinged to both the drive and driven yokes (11, 12). First and second joint units (100, 200) connect the two yoke parts of the middle yoke (3) to the drive and driven yokes (11, 12) respectively. The two joint units (100, 200) transmit the rotating force of the drive shaft (1) to the driven shaft (2) through the three yokes while allowing the drive and driven yokes (11, 12), with the drive and driven shafts (1, 2) to be rotated around the first and second joint units (100, 200) at the same rotating angle and in the same direction as said drive yoke (1) being rotatable around the first joint unit (100) at an angle υ of 0° ∫ υ ≤ 90° in any direction.

Description

THREE-DIMENSIONAL POWER TRANSMISSION DEVICE
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to, in general, a power transmission device, and more particularly, to a three- dimensional power transmission device capable of transmitting the rotating force of a drive shaft to a driven shaft while allowing the driven shaft to be rotated at the same rotating angle and in the same direction as the drive shaft being rotatable at an angle θ of 0° < θ < 90° in any direction.
Description of the Prior Art
As well known to those skilled in the art, a power transmission device or mechanism, such a an universal joint member, is used for transmitting the rotating force of a drive shaft to a driven shaft regardless of the angle between the drive and driven shafts.
However, it is almost impossible to transmit the rotating force of the drive shaft to the driven shaft using a single device, with the angle between the drive and driven shafts being larger than 30°.
Thus, when the angle between the drive and driven shafts is larger than 30°, the typical power transmission device demands two or three typical universal joints or an additional transmission device, thus complicating the construction, enlarging the volume and size and increasing the weight of the device. As a result, such a transmission device is problematic in that it fails to be effectively used in industrial fields such as the robotics industry and space engineering, etc. being in need of an essential power transmission mechanism.
In order to overcome the above problems, a multi-angle axis, proposed by the inventors of this invention, is disclosed in Korean Patent Publication Nos. 89-1513 and 91- 951. In the above Korean Patents, when the angle between the drive and driven shafts is an acute angle of 0° < a < 90°, the rotating force of the drive shaft is effectively transmitted to the driven shaft by the multi-angle axis without requiring any combination of power transmission devices or an additional transmission device.
Such a multi-angle axis comprises a pair of semi-circular drive ring members, slidably connected to the end portions of drive and driven shafts, and small or large gears. The gears are mounted to the end portions of the drive ring members. The multi-angle axis further comprises connection pins mounted to the end portions of the semi-circular drive ring members by pivot pins. The connection pins, inserted into rotatable central rings, are slid and rotated along the inner surface of the central rings.
However, the above multi-angle axis has problems in that semi-circular holes are formed on the drive and driven shafts because the semi-circular drive ring members are inserted into the semi-circular holes of the drive and driven shafts. Also, the contact portions between the drive ring members and holes are easily abraded due to the sliding motion of the drive ring members, thereby causing the drive ring members to be broken. In order to overcome the above problems, a power transmission device, proposed by the inventors of this invention, is disclosed in Korean Utility Model Publication No. 95-6376. Such a device includes a pair of transmission gears and small gears. In such a case, when the angle between the drive and driven shafts is an acute angle of 0° < a < 90° , the rotating force of the drive shaft is effectively transmitted to the driven shaft by means of engagement of a pair of transmission gears with a pair of small gears.
However, the above transmission device demands lubricant for reducing the operational noises caused from the engaging junction of the gears. Also, the engaging teeth of the gears may be easily abraded by the load acting on the engaging teeth.
Therefore, in order to overcome the above problems, a power transmission device is disclosed in Korean Patent Application No. 95-12923 applied by the inventors of this invention.
The power transmission device of Korean Patent Application No. 95-12923 is capable of transmitting the rotating force of a drive shaft to a driven shaft while allowing the driven shaft to be rotated at the same rotating angle and in the same direction as the drive shaft being rotatable at an angle a of 0° < a < 90° in any direction, thereby reducing the operational noises and load of the device. However, the above device comprises a plurality of parts and drive ring members consisting of bearings and so it is difficult to produce the device. Furthermore, due to the wearing of the ring member, consisting of bearings, the drive shaft may fail to completely or correctly transmit its rotating force to the driven shaft after the device has been used for a long time,
SUMMARY OF THE INVENTION
Accordingly, the present invention has been made with the above problems occurring in the prior art in mind, and an object of the present invention is to provide a three- dimensional power transmission device capable of transmitting the rotating force of a drive shaft to a driven shaft while allowing the driven shaft to be rotated at the same rotating angle and in the same direction as the drive shaft being rotatable at an angle θ of 0° < θ < 90° in any direction.
In order to accomplish the above object, the present invention provides a three-dimensional power transmission device, comprising: a drive yoke fixedly connected to a drive shaft; a driven yoke fixedly connected to a driven shaft; a middle yoke hinged to both the drive and driven yokes, thus universally transmitting the rotating force of the drive shaft to the driven shaft, the middle yoke having two yoke parts at its opposite ends; and first and second joint units universally connecting the two yoke parts of the middle yoke to the drive and driven yokes respectively, the two joint units transmitting the rotating force of the drive shaft to the driven shaft through the three yokes while allowing the drive and driven yokes, with the drive and driven shafts, to be rotated around the first and second joint units at the same rotating angle and in the same direction as said drive yoke being rotatable around the first joint unit at an angle θ of 0° < θ < 90° in any direction. The first and second joint units have the same construction, each of the two joint units comprising a cross member with both a vertical part of the cross member being hinged to the drive or driven yoke and a horizontal part of the cross member being hinged to each of the two yoke parts of the middle yoke. The three-dimensional power transmission device further comprises a first bevel gear fitted over the top end of the vertical part of the cross member; a balance ring fitted over the bottom end of the vertical part; a second bevel gear fitted over one end of the horizontal part of the cross member, the second bevel gear engaging with said first bevel gear and having a belt groove on its outer surface; a pulley fitted over the other end of the horizontal part, the pulley having a belt groove on its outer surface; and a needle bearing provided on each end of the vertical and horizontal parts of the cross member, thus rotatably holding the cross member at each bearing seat of the drive, driven and middle yokes .
BRIEF DESCRIPTION OF THE DRAWINGS
The above object, and other features and advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings , in which : Fig. 1 is a schematic perspective view of a three- dimensional power transmission device in accordance with the preferred embodiment the present invention;
Fig. 2 is an exploded perspective view of the power transmission device according to the embodiment of the present invention;
Fig. 3 is a perspective view showing the essential parts of the power transmission device according to the embodiment of the present invention; Fig. 4 is a top view showing the power transmission device according to the embodiment of this invention;
Fig. 5 is a side view of the power transmission device according to the embodiment of this invention;
Fig. 6 is a sectional view of the power transmission device taken along the line A-A of Fig. 5;
Fig. 7 is a sectional view of the power transmission device taken along the line B-B of Fig. 4;
Fig. 8 is a sectional view of the power transmission device taken along the line C-C of Fig. 4; Fig. 9 is a view illustrating the drive shaft of Fig. 6, which is rotated and maintained at an angle θ of 0° < θ < 45°;
Fig. 10 is a view illustrating the power transmission device rotated from the position of Fig. 9;
Fig. 11 is a view illustrating the drive shaft of Fig. 8, which is rotated and maintained at an angle θ of 0° < θ < 45°;
Fig. 12 is a view illustrating the power transmission device rotated from the position of Fig. 11;
Fig. 13 is a view illustrating the drive shaft of Fig. 6, which is rotated and maintained at an angle θ of 45° < θ < 90°; and Fig. 14 is a view illustrating the drive shaft of Fig. 8, which is rotated and maintained at an angle θ of 45° < θ < 90°.
DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown in Fig. 2, a three-dimension power transmission device according to the present invention comprises a drive yoke 11 fixedly connected to a drive shaft 1, a driven yoke 12 fixedly connected to a driven shaft 2, and a middle yoke 3 hinged to both the drive and driven yokes 1 and 2. Also, the middle yoke 3 has two yoke parts at its opposite ends, while first and second joint units 100 and 200 universally connect the two yoke parts of the middle yoke 3 to the drive and driven yokes 11 and 12, respectively.
The first and second joint units 100 and 200 have the same construction and are mounted to shafts 1 and 2 in the same manner, but the first joint unit 100 is fixedly mounted to the drive shaft 1, while the second joint unit 200 is fixedly mounted to the driven shaft 2.
However, when it is necessary to transmit the rotating force of an engine or machine from the driven shaft 2 to the drive shaft 1 of the power transmission device of this invention, the position of the drive shaft 1 is changed with that of the driven shaft 2. Thus, the distinction between the drive and driven shafts 1 and 2 is insignificant. However, such drive and driven shafts 1 and 2 of the power transmission device of this invention are distinguished hereinbelow for easy description. As shown in Figs. 2 to 8, the first joint unit 100 is connected to both the drive yoke 11 and the middle yoke 3, while the second joint unit 200 is connected to both the middle yoke 3 and the driven yoke 12.
The first joint unit 100 comprises a first cross member 101 with vertical and horizontal parts. That is, top and bottom ends of the vertical part of the member 101 are respectively hinged to the two yoke parts 103 and 109 of the drive yoke 11, while both ends of the horizontal part of the member 101 are respectively hinged to the two yoke parts 107 and 112 of the middle yoke 3.
In addition, a first bevel gear 102 is fitted over the top portion 101-1 of the vertical part of the first cross member 101, while a balance ring 108 is fitted over the bottom portion 101-3 of the vertical part. Also, a second bevel gear 106, having a pair of belt grooves 105 on its outer surface, is fitted over one end portion 101-2 of the horizontal part of the first cross member 101 and engages with the first bevel gear 102. A pulley 111, having a pair of belt grooves 110 on its outer surface, is fitted over the other end portion 101-4 of the horizontal part of the cross member 101. Also, a plurality of needle bearings 104 and snap rings 6 are provided on each end of the vertical and horizontal parts of the cross member 101, thereby rotatably holding the cross member 101 at each bearing seat of the drive and middle yokes 11 and 3. In the same manner as described for the first joint unit
100, the second joint unit 200 comprises a second cross member 201 with vertical and horizontal parts. That is, top and bottom ends of the vertical part of the member 201 are respectively hinged to the two yoke parts 203 and 209 of the driven yoke 12, while both ends of the horizontal part of the member 201 are respectively hinged to the two yoke parts 207 and 212 of the middle yoke 3.
In addition, a first bevel gear 202 is fitted over the top portion 201-1 of the vertical part of the member 201, while a balance ring 208 is fitted over the bottom portion 201-3 of the vertical part. Also, a second bevel gear 206, having a pair of belt grooves 205 on its outer surface, is fitted over one end portion 201-2 of the horizontal part of the second cross member 201 and engages with the first bevel gear 202. A pulley 211, having a pair of belt grooves 210 on its outer surface, is fitted over the other end portion 201-4 of the horizontal part of the second cross member 201. Also, a plurality of needle bearings 104 and snap rings 6 are provided on each end of the vertical and horizontal parts of the cross member 201, thereby rotatably holding the cross member 201 at each bearing seat of the driven and middle yokes 12 and 3.
Furthermore, the two second bevel gears 106 and 206 of the first and second joint units 100 and 200 are connected to each other through an endless belt 4 in such a manner that the belt 4 wraps around and intersects between the two second bevel gears 106 and 206. Also, the two pulleys 111 and 211 of the first and second joint units 100 and 200 are connected to each other through an endless belt 5 in such a manner that the belt 5 wraps around and intersects between the two pulleys 111 and 211.
A fitting member 9 is fixedly mounted to each of the two first bevel gears 102 and 202, two second bevel gears 106 and 206, two balance wheels 108 and 208, and two pulleys 111 and 211. Such a fitting member 9, having a screw hole 8, is fitted in the mouth of each bearing seat of the drive, driven and middle yokes 11, 12 and 3 in such a manner that the member 9 is fixed at its place in each bearing seat by a set bolt 7 passing through the screw hole 8. After the first joint unit 100 is completely mounted at the junction between the drive yoke 11 and the middle yoke 3, the second joint unit 200 is mounted at the junction between the driven yoke 12 and the middle yoke 3 in the same manner as described for the first joint unit 100, thus accomplishing assemblage of the device of this invention. Also, as shown in Fig. 1, the power transmission device according to this invention is protected by a bellows member 90 surrounding the device.
The operation of the power transmission device according to the preferred embodiment of this invention is described hereinbelow.
First, as shown in Figs. 6 and 7, when the drive and driven shafts 1 and 2 are coaxially arranged, the rotating force of the drive shaft 1 is transmitted to the driven shaft 2 as follows.
The drive shaft 1 is mounted to a power generating means such as an engine, through a conventional manner.
When the engine is started, the rotating force of the engine is transmitted to the drive shaft, thus rotating the drive shaft 1. The rotating force of the drive shaft 1 is transmitted to the first joint unit 100 through the drive yoke 11. Thus, the first joint unit 100 is rotated with the middle yoke 3.
That is, the rotating force of the drive shaft 1 is completely transmitted to the first cross member 101 because the top and bottom ends of the vertical part of the member 101 are hinged to the two yoke parts 103 and 109 of the drive yoke 11. The middle yoke 3 is rotated by the rotating force of the cross member 101 because both ends of the horizontal part of the member 101 are hinged to the two yoke parts 107 and 112 of the middle yoke 3.
In such a case, the driven yoke 12 is rotated by the rotating force of the middle yoke 3 because both ends of the horizontal part of the second cross member 201 are hinged to the two yoke parts 207 and 212 of the middle yoke 3, and the top and bottom ends of the vertical part of the member 201 are hinged to the two yoke parts 203 and 209 of the driven yoke 12. Therefore, the rotating force of the drive shaft 1 is completely transmitted to the driven shaft 2. Second, as shown in Fig. 9, when the drive and driven shafts 1 and 2 are arranged with each other while being rotated at a certain angle, the rotating force of the drive shaft 1 is transmitted to the driven shaft 2 as explained below. That is, when the drive shaft 1 is rotated at an angle θ of 0° < θ < 45° from a horizontal plane, the angle λ between the drive and driven shaft 1 and 2 is maintained at the angle of 0° < λ < 90°.
When the drive shaft 1, fixed to the drive yoke 11, is upwardly or downwardly rotated around the middle yoke 3 at an angle θ of 0° < θ < 45° relative to a horizontal axis, the first bevel gear 102 of the first joint unit 100 revolves from its top position in the same direction as the rotating direction of the drive shaft 1. In such a case, the second bevel gear 106 of the first joint unit 100, engaging with the first bevel gear 102, is rotated clockwise or counterclockwise in the drawings at the same rotating angle as the revolving angle of the first bevel gear 102. The second bevel gear 106 thus rotates the belt 4. In the above state, the rotating length of the belt 4 is influenced by the rotating angle of the second bevel gear 106. Due to such a rotation motion of the belt 4, the second bevel gear 206 of the second joint unit 200 is rotated. In such a case, the rotating angle of the bevel gear 206 is equal to that of the other bevel gear 106, while the rotating direction of the bevel gear 206 is opposite that of the other bevel gear 106 since the belt 4 intersects between the two gears 106 and 206.
Also, the first bevel gear 202 of the second joint unit 200, engaging with the second bevel gear 206, is revolved at the same angle as the rotating angle of the second bevel gear 206. Thus, the driven yoke 12, fixedly mounted to the first gear 202, is upwardly or downwardly rotated by revolving the first gear 202 of the second joint unit 200. Therefore, the driven shaft 2, fixed to the driven yoke 12, is upwardly or downwardly rotated. As a result, the rotating angle of the driven shaft 2 is maintained at a same angle θ of 0° < θ < 45° as the rotating angle of the drive shaft 1. Therefore, when the rotating angles θ of the drive and driven shafts 1 and 2 are 0° < θ < 45°, the angle χ between the drive and driven shafts 1 and 2 is maintained at the angle of 0° < χ < 90°.
In such a case, the transmission process of the rotating force of the drive shaft 1 is described below with Figs. 9 to 12.
The rotating force of the drive shaft 1 is transmitted to the first joint unit 100 through the drive yoke 11. Thus, the first joint unit 100 is rotated with the middle yoke 3.
That is, when the drive yoke 11 is rotated by the rotating force of the drive shaft 1, the vertical part of the first cross member 101 is rotated. In such a case, the vertical part of the member 101 is rotated and revolved because the needle bearings 104, mounted to the top and bottom portion 101-1 and 101-3 of the vertical part of the member 101, are seated in the two yoke parts 103 and 109 of the drive yoke 11.
In this state, when the drive shaft 1 is rotated at the rotating angle θ of 0° < θ < 45°, the vertical part of the first cross member 101 is rotated. Then, the first bevel gear 102, fixed to the top portion 101-1 of the vertical part of the member 101, is forcibly rotated. Accordingly, the second bevel gear 106 is rotated by the rotating force of the first bevel gear 102 because the second bevel gear 106, fixed to one portion 101-2 of the horizontal part of the cross member 101, engages with the first bevel gear 102. As a result, the horizontal part of the first cross member 101 is rotated on its axis by the rotating force of the second bevel gear 106 because the needle bearings 104, mounted to both ends of the horizontal part of the member 101, are seated in the yoke parts 107 and 112 of the middle yoke 3. In such a case, the rotating force of the vertical part of the cross member 101 is completely transmitted to the horizontal part of the member 101. Also, the middle yoke 3 is rotated by the rotating force of the horizontal part of the cross member 101 because both ends of the horizontal part of the member 101 are hinged to the yoke parts 107 and 112 of the middle yoke 3.
Therefore, the driven yoke 12 is rotated by the middle yoke 3 with the second joint unit 200 jointing the middle yoke
3 to the driven yoke 12. That is, the second cross member 201 is rotated because both ends of the horizontal part of the member 201 are hinged to the two yoke parts 207 and 212 of the middle yoke 3, respectively.
In such a case, the two belts 4 and 5, wrapping on both the belt grooves 105 of the second bevel gear 106 and the belt grooves 110 of the pulley 111, are respectively rotated clockwise or counterclockwise by the rotating force of the middle yoke 3. Thus, the rotating angle of both the second bevel gear 206 and the pulley 211 is equal to that of the two belts 4 and 5, while the rotating direction of both the second bevel gear 206 and the pulley 211 is opposite that of the two belts 4 and 5.
In the above state, the first bevel gear 202, engaging with the second bevel gear 206 of the second joint unit 200, is revolved at the same rotating angle as the revolving angle of the first bevel gear 206. Due to such a revolution motion of the first bevel gear 202, the driven yoke 12, hinged to the first bevel gear 202, is upwardly or downwardly rotated.
Thus, the driven shaft 2 fixed to the driven yoke 12 is upwardly or downwardly rotated. Therefore, the driven shaft 2 is rotated and maintained at the same angle as the rotating angle of the drive shaft 1.
The above state is prior to the state of Fig. 11.
Fig. 12 is a schematic view illustrating the rotating function of the power transmission device of Fig. 11. In such a case, the vertical part of the first cross member 101 is rotated at the same angle θ as the rotating angle of the drive shaft 1, while the vertical part is maintained at a vertical position relative to the drive shaft
1. That is, the vertical part of the cross member 101 is rotated around the horizontal part with the needle bearings
104 being mounted to the two yoke parts 107 and 112 of the middle yoke 3.
Due to such a rotating motion of the vertical part of the first cross member 101, the horizontal part of the cross member 101 is rotated on its axis at the same angle as the rotating angle of the drive shaft 1 in the two yoke parts 107 and 112 of the middle yoke 3.
Accordingly, both the second bevel gear 106 and the pulley 111, mounted to both ends of the horizontal part of the first cross member 101, are rotated at the same angle as the rotating angle of the horizontal part of the member 101.
Due to such a rotating motion of the second bevel gear
106 and the pulley 111, the two belts 4 and 5, wrapping on the belt grooves 105 and 110, are rotated at the same angle and in the same direction as the rotating angle and the direction of the second bevel gear 106 and the pulley 111, respectively. Thus, both the second bevel gear 206 and pulley 211 of the second joint unit 200 are forcibly rotated by the rotating force of the two belts 4 and 5. In such a case, the horizontal part of the second cross member 201, with the second bevel gear 206 and the pulley 211, is rotated around the two yoke parts 107 and 112 of the middle yoke 3 by the rotating force of both the second bevel gear 206 and the pulley 211. Due to such a rotating motion of the horizontal part of the cross member 201, the vertical part of the second cross member 201 is shifted around the horizontal part of the member
201 at the same angle as the rotating angle θ of the vertical part of the first cross member 101. Thus, since the driven yoke 12 is shifted at the same angle as the rotating angle of the vertical part of the cross member 201, the driven shaft 2 is maintained at the same angle as the rotating angle of the drive shaft 1. Due to such a function, the rotating force of the drive shaft 1 is completely transmitted to the first joint unit 100 through the drive yoke 11. As a result, the first joint unit 100 is rotated with the middle yoke 3.
That is, when the drive yoke 11 is rotated by the rotating force of the drive shaft 1, the vertical part of the first cross member 101 is rotated. In such a case, the vertical part of the member 101 is rotated and revolved because the needle bearings 104, mounted to both the top and bottom portion 101-1 and 101-3 of the vertical part of the member 101, are seated in the two yoke parts 103 and 109 of the drive yoke 11.
In this state, when the drive shaft 1 is rotated and maintained at the rotating angle θ of 0° < θ < 45°, the vertical part of the first cross member 101 is rotated. Then, the first bevel gear 102, fixed to the top portion 101-1 of the vertical part of the member 101, is forcibly rotated. Accordingly, the second bevel gear 106 is rotated by force according to the revolution of the first bevel gear 102 because the second bevel gear 106, fixed to one end portion 101-2 of the horizontal part of the cross member 101, engages with the first bevel gear 102. As a result, the horizontal part of the first cross member 101 is rotated on its axis by the rotating force of the second bevel gear 106 because the needle bearings 104, mounted to both ends of the horizontal part of the member 101, are sated in the yoke parts 107 and 112 of the middle yoke 3. In such a case, the rotating force of the vertical part of the first cross member 101 is completely transmitted to the horizontal part of the member 101. Also, the middle yoke 3 is rotated by the rotating force of the horizontal part of the cross member 101 because both ends of the horizontal part of the member 101 are hinged to the yoke parts 107 and 112 of the middle yoke 3.
Therefore, the driven yoke 12 is rotated by the rotating force of the middle yoke 3. That is, the second cross member 201 is rotated because both ends of the horizontal parts of the member 201 are hinged to the two yoke parts 207 and 212 of the middle yoke 3, respectively.
In such a case, the two belts 4 and 5, wrapping on the belt grooves 105 of the second bevel gear 106 and the belt grooves 110 of the pulley 111, are rotated clockwise or counterclockwise by the rotating force of the middle yoke 3. Thus, the rotating angle of both the second bevel gear 206 and the pulley 211 is equal to that of the two belts 4 and 5, while the rotating direction of both the second bevel gear 206 and the pulley 211 is opposite that of the two belts 4 and 5. In the above state, the first bevel gear 202, engaging with the second bevel gear 206 of the second joint unit 200, is rotated at the same rotating angle as the revolving angle of the first bevel gear 206. Due to such a rotating force of the first bevel gear 202, the driven yoke 12, hinged to the first bevel gear 202, is upwardly or downwardly rotated. Thus, the driven shaft 2, fixed to the driven yoke 12, is upwardly or downwardly rotated.
Therefore, the driven shaft 2 is rotated at the same angle as the rotating angle of the drive shaft 1. The above state is illustrated in Figs. 11 and 12.
As mentioned above, the drive and driven shafts 1 and 2 are rotated at the rotating angle θ of 0° < θ < 45°, respectively. In such a case, the angle X between the drive and driven shafts 1 and 2 is maintained at the angle of 0° <
X < 90°, while the drive shaft 1 is half rotated.
The remaining half rotation of the drive shaft 1 is symmetrized to the prior half rotation of the drive shaft 1 illustrated in Figs. 9, 10, 11 and 12. Thus, the remaining half rotation of the drive shaft 1 is not deemed necessary.
Third, as shown in Figs. 13 and 14, when the drive shaft
1 is rotated at an angle θ of 45° < θ < 90°, the angle X between the drive and driven shafts 1 and 2 maintains at an angle of 90° < X < 180° as follows. When the drive shaft 1 is upwardly or downwardly rotated at an angle θ of 45° < θ < 90°, the first bevel gear 102, fixed to the drive yoke 11, is revolved in the same direction as the rotating direction of the drive shaft 1.
In such a case, the maximum revolution of the first bevel gear 102 is a quarter revolution. Due to the revolution of the first bevel gear 102 of the first joint unit 100, the second bevel gear 106, engaging with the first bevel gear 102, is rotated clockwise or counterclockwise in the drawings at the same angle as the revolving angle of the first bevel gear 102. Thus, the second bevel gear 106 rotates the belt 4 at the same angle as the revolving angle of the first bevel gear 102. In the above state, when the drive shaft 1 is rotated at the maximum rotating angle θ of 90°, the drive shaft 1 is coaxial with the horizontal part of the first cross member 101.
Due to such a rotating force of the belt 4, the second bevel gear 206 of the second joint unit 200 is rotated. In such a case, the rotating angle of the bevel gear 206 is equal to that of the other bevel gear 106, while the rotating direction of the bevel gear 206 is opposite that of the other bevel gear 106 since the belt 4 intersects between the two gears 106 and 206.
Also, the first bevel gear 202 of the second joint unit 200, engaging with the second bevel gear 206, is rotated at the same angle as the rotating angle of the second bevel gear 206. Thus, the driven yoke 12, fixedly mounted to the first gear 202, is upwardly or downwardly rotated by the rotating force of the first gear 202 of the second joint unit 200.
Thus, the driven shaft 2, fixed to the driven yoke 12, is upwardly or downwardly rotated. As a result, the rotating angle of the driven shaft 2 is maintained at the same angle θ of 45° < θ < 90° as the rotating angle of the drive shaft 1.
In such a case, when the driven shaft 2 is rotated at the maximum rotating angle θ of 90°, the driven shaft 2 is coaxial with the horizontal part of the first cross member 101. Thus, the driven shaft 2 is parallel to the drive shaft 1 as shown in Fig. 13.
Therefore, when the drive and driven shafts 1 and 2 are rotated at an angle θ of 45° < θ < 90°, the angle X between the drive and driven shafts 1 and 2 is maintained at an angle of 90° < X < 180°.
In such a case, the transmission process of the rotating force of the drive shaft 1 is similar to the process of Figs.
9 to 11, where the quarter rotation of the drive shaft 1 is performed at the rotating angle θ of 45° < θ < 90° or at the angle X of 90° < λ ≤ 180°.
Fig. 14 is a view illustrating the quarter rotated state of the drive shaft 1. In such a case, when the drive shaft 1 is rotated at the maximum rotating angle of 90°, the horizontal part of the first cross member 101 is maintained at a vertical position relative to the drive shaft 1.
When the drive shaft 1 is rotated at the angle θ of 45°
< θ < 90°, the horizontal part of the cross member 101, hinged to the two yoke parts 107 and 112 of the middle yoke 3, is rotated on its axis at the same angle as the rotating angle of the drive shaft 1.
Accordingly, both the second bevel gear 106 and the pulley 111, mounted to both ends of the horizontal part of the first cross member 101, are rotated at the same angle as the rotating angle of the horizontal part of the member 101.
Due to such a rotating motion of both the second bevel gear 106 and the pulley 111, the two belts 4 and 5, wrapping on the belt grooves 105 and 110, are rotated at the same angle and in the same direction as the rotating angle and direction of the second bevel gear 106 and pulley 111, respectively.
Thus, both the second bevel gear 206 and the pulley 211 of the second joint unit 200 are forcibly rotated by the rotating force of the two belts 4 and 5.
In such a case, the horizontal part of the second cross member 201, with the second bevel gear 206 and the pulley 211, is rotated around the two the yoke parts 107 and 112 of the middle yoke 3 by the rotating force of both the second bevel gear 206 and the pulley 211.
Due to such a rotating motion of the horizontal part of the cross member 201, the vertical part of the member 201 is shifted around the horizontal part of the member 201 at the same angle as the rotating angle θ of the vertical part of the first cross member 101.
Thus, since the driven yoke 12 is shifted at the same angle as the rotating angle of the vertical part of the second cross member 201, the rotating angle of the driven shaft 2 is maintained at the same angle as the rotating angle of the drive shaft 1. That is, the rotating angle θ of the driven shaft 2 is maintained at 45° < θ < 90°. In such a case, when the driven shaft 2 is rotated at the maximum rotating angle θ of 90°, the driven shaft 2 is coaxial with the horizontal part of the first cross member 101. Thus, the driven shaft 2 is parallel to the drive shaft 1 as shown in Fig. 14. Therefore, when the drive and driven shafts 1 and 2 are rotated at an angle θ of 45° < θ < 90°, the angle X between the drive and driven shafts 1 and 2 is maintained at an angle of 90° < λ ≤ 180°.
In such a case, the transmission process of the rotating force of the drive shaft 1 is similar to the process of Figs. 9 to 12, where the half rotation of the drive shaft 1 is performed at the rotation angle θ of 45° < θ < 90° or at the angle of 90° < X ≤ 180° .
The remaining half rotation of the drive shaft 1, after the prior half rotation of the drive shaft 1, is symmetrized to the prior half rotation of the drive shaft 1 illustrated in Figs. 9, 10, 11 and 12. Thus, the remaining half rotation of the drive shaft 1 is not deemed necessary.
As mentioned above, the three-dimensional power transmission device of this invention comprises first and second joint units for completely transmitting the rotating force of the drive shaft to the driven shaft while allowing the driven shaft to be rotated around the first and second joint units at the same rotating angle and in the same direction as the drive shaft being rotatable around the first joint unit at an angle θ of 0° < θ < 90° in any direction.
Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims .

Claims

WHAT IS CLAIMED IS:
1. A three-dimensional power transmission device, comprising: a drive yoke fixedly connected to a drive shaft; a driven yoke fixedly connected to a driven shaft; a middle yoke hinged to both the drive and driven yokes, thus universally transmitting the rotating force of said drive shaft to said driven shaft, said middle yoke having two yoke parts at its opposite ends; and first and second joint units universally connecting the two yoke parts of said middle yoke to said drive and driven yokes respectively, said two joint units transmitting the rotating force of the drive shaft to the driven shaft through said three yokes while allowing the drive and driven yokes, with the drive and driven shafts, to be rotated around the first and second joint units at the same rotating angle and in the same direction as said drive yoke being rotatable around said first joint unit at an angle ╬╕ of 0┬░ < ╬╕ < 90┬░ in any direction.
2. The three-dimensional power transmission device as claimed in Claim 1, wherein said first and second joint units have the same construction, each of said two joint units comprising a cross member with both a vertical part of said cross member being hinged to said drive or driven yoke and a horizontal part of said cross member being hinged to each of said two yoke parts of the middle yoke.
3. The three-dimensional power transmission device as claimed in Claim 2, further comprising: a first bevel gear fitted over the top end of said vertical part of the cross member; a balance ring fitted over the bottom end of said vertical part; a second bevel gear fitted over one end of said horizontal part of the cross member, said second bevel gear engaging with said first bevel gear and having a belt groove on its outer surface; a pulley fitted over the other end of said horizontal part, said pulley having a belt groove on its outer surface; and a needle bearing provided on each end of said vertical and horizontal parts of the cross member, thus rotatably holding the cross member at each bearing seat of said drive, driven and middle yokes.
4. The three-dimensional power transmission device as claimed in Claim 3, wherein the two second bevel gears of said first and second joint units are connected to each other through an endless belt, said belt wrapping around and intersecting between the two second bevel gears.
5. The three-dimensional power transmission device as claimed in Claim 3, wherein the two pulleys of said first and second joint units are connected to each other through an endless belt, said belt wrapping around and intersecting between the two pulleys.
6. The three-dimensional power transmission device as claimed in Claim 3, further comprising: a fitting member fixedly mounted to each of said first bevel gear, second bevel gear, balance wheel and pulley, said fitting member having a screw hole and being fitted in the mouth of each bearing seat of said drive, driven and middle yokes and being fixed at its place in each bearing seat by a set bolt passing through said screw hole.
PCT/KR1998/000223 1997-07-29 1998-07-23 Three-dimensional power transmission device WO1999006726A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR1019970035718A KR100236406B1 (en) 1997-07-29 1997-07-29 3d solid power transfer apparatus
KR1997/35718 1997-07-29

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Application Number Title Priority Date Filing Date
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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2089471A (en) * 1980-12-15 1982-06-23 Borg Warner Universal joint
GB2096736A (en) * 1981-04-15 1982-10-20 Zeller Corp Double universal joint
WO1995002773A1 (en) * 1993-07-14 1995-01-26 G. Elbe & Sohn Gmbh & Co. Double cardan joint

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2089471A (en) * 1980-12-15 1982-06-23 Borg Warner Universal joint
GB2096736A (en) * 1981-04-15 1982-10-20 Zeller Corp Double universal joint
WO1995002773A1 (en) * 1993-07-14 1995-01-26 G. Elbe & Sohn Gmbh & Co. Double cardan joint

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KR100236406B1 (en) 1999-12-15

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