Patent Grant
8864591
1. Field of the Invention
The present invention relates to a propeller shaft and a constant velocity universal joint used therein, which are used in wheeled motor vehicles.
2. Description of the Related Art
Usually, the propeller shaft for the wheeled motor vehicle has a split construction including a drive shaft that is adapted to connect to an output shaft of a transmission, a driven shaft that is adapted to connect to a differential gear and a coupling device, such as, constant velocity universal joint, Cardin joint or the like, that is operatively disposed between mutually facing ends of the drive and driven shafts. In practical use, an axially middle portion of the propeller shaft is rotatably held by a support device fixed to a body of the vehicle. Furthermore, for holding a grease in the coupling device, there is provided a boot between the drive shaft and the coupling device.
One of such boots is disclosed by U.S. Pat. No. 7,470,198. The boot disclosed by the patent is generally conical in shape and made of a soft rubber or flexible plastic. A larger diameter outer portion of the boot is secured to an outer cylindrical member of a constant velocity universal joint (viz., coupling device) through an annular metal retainer and a smaller diameter inner portion of the boot is secured to the drive shaft through an annular metal band. With provision of the boot, an interior of the constant velocity universal joint is protected from entry of muddy water, dusts and the like and furthermore a grease in the interior is suppressed from leakage.
However, usage of the boot for protecting the interior of the universal joint from entry of foreign matter has the following drawbacks. That is, it often happens that fitting the boot to a desired position of the propeller shaft takes a lot of time due to a complicated fitting process.
That is, at first, the boot is fixed at its larger diameter outer portion to an outer cylindrical member of the universal joint to produce a semifinished unit of a propeller shaft. Usually, this fitting process is carried out in an automotive component factory. Then, the semifinished unit is transported to a vehicle assembling factory. At this assembling factory, the semifinished unit of propeller shaft is connected to a vehicle body and then the smaller diameter inner portion of the boot is fixed to a drive shaft (viz., output shaft of a transmission).
As will be understood from the above, such fitting process is troublesome and thus takes a lot of time thereby causing increase in production cost of the vehicle.
Accordingly, the present invention is provided by taking the above-mentioned drawbacks of the conventional technology into consideration and aims to provide a propeller shaft that is free of the above-mentioned drawbacks.
In accordance with a first aspect of the present invention, there is provided a propeller shaft which comprises an inner cylindrical member having a center through bore, the center through bore having a splined cylindrical inner wall with which a splined cylindrical outer wall of a shaft is engaged; an outer cylindrical member disposed around the inner cylindrical member; a torque transmitting unit installed between the inner and outer cylindrical members to transmit a torque between the inner and outer cylindrical members; a sleeve member coaxially connected to the center through bore of the inner cylindrical member, the sleeve member permitting passage of the splined cylindrical outer wall of the shaft therethrough before effecting the engagement between the splined cylindrical outer wall of the shaft and the splined cylindrical inner wall of the inner cylindrical member; a boot unit having one end fixed to the outer cylindrical member and the other end fixed to the sleeve member thereby to hermetically close one open side of an interior of the outer cylindrical member, the interior containing therein a grease; and a positioning mechanism that effects a relative axial positioning between the shaft and the inner cylindrical member when the splined cylindrical outer wall of the shaft is inserted through the sleeve member into a given position of the center through bore of the inner cylindrical member.
In accordance with a second aspect of the present invention, there is provided a propeller shaft which comprises an inner cylindrical member having a center through bore, the center through bore having a splined cylindrical inner wall with which a splined cylindrical outer wall of a shaft is engaged; an outer cylindrical member disposed around the inner cylindrical member; a torque transmitting unit installed between the inner and outer cylindrical members to transmit a torque between the inner and outer cylindrical members; a sleeve member coaxially connected to the center through bore of the inner cylindrical member, the sleeve member permitting passage of the splined cylindrical outer wall of the shaft therethrough before effecting the engagement between the splined cylindrical outer wall of the shaft and the splined cylindrical inner wall of the inner cylindrical member; a flexible boot unit having one end fixed to the outer cylindrical member and the other end fixed to the sleeve member thereby to hermetically close one open side of an interior of the outer cylindrical member, the interior containing therein a grease; a seal ring arranged between the sleeve member and the shaft to suppress entry of foreign matter into the center through bore of the inner cylindrical member; and a positioning mechanism that effects a relative axial positioning between the shaft and the inner cylindrical member when the splined cylindrical outer wall of the shaft is inserted through the sleeve member into a given position of the center through bore of the inner cylindrical member.
In accordance with a third aspect of the present invention, there is provided a constant velocity universal joint which comprises an inner cylindrical member having a center through bore, the center through bore having a splined cylindrical inner wall with which a splined cylindrical outer wall of a shaft is engaged; an outer cylindrical member disposed around the inner cylindrical member; a torque transmitting unit installed between the inner and outer cylindrical members to transmit a torque between the inner and outer cylindrical members; a sleeve member coaxially connected to the center through bore of the inner cylindrical member, the sleeve member permitting passage of the splined cylindrical outer wall of the shaft therethrough before effecting the engagement between the splined cylindrical outer wall of the shaft and the splined cylindrical inner wall of the inner cylindrical member; a boot unit having one end fixed to the outer cylindrical member and the other end fixed to the sleeve member thereby to hermetically close one open side of an interior of the outer cylindrical member, the interior containing therein a grease; and a positioning mechanism that effects a relative axial positioning between the shaft and the inner cylindrical member when the splined cylindrical outer wall of the shaft is inserted through the sleeve member into a given position of the center through bore of the inner cylindrical member.
Other objects and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings, in which:
In the following, six embodiments 1a, 1b, 1c, 1d, 1e and 1f of the present invention will be described in detail with reference to the accompanying drawings.
In the following description, various directional terms, such as right, left, upper, lower, rightward and the like are used for ease of explanation. It is however to be noted that such terms are to be understood with respect to only a drawing or drawings on which a corresponding element or portion is shown.
Referring to
As is seen from
As is seen from
As shown in the drawings, medium diameter intermediate portion 12 is shorter in length than smaller diameter right shaft portion 13. A cylindrical outer surface of medium diameter intermediate portion 12 is formed at an axially middle part thereof with an annular groove 12a and a seal ring 14 made of a synthetic rubber is tightly received in annular groove 12a.
As shown, a cylindrical outer surface of smaller diameter right shaft portion 13 is splined, that is, the cylindrical outer surface is formed with a plurality of axially extending splines 15. As shown, smaller diameter right shaft portion 13 has a tapered right end 13a.
As is seen from
Snap ring 16 is made of a resilient metal and has a generally circular cross section as is seen from
As is seen from
As is seen from
Within smaller diameter right end portion 17c of outer cylindrical member 17, there is press-fitted a circular seal cap 22, and between a larger diameter front end 17d of outer cylindrical member 17 and an after-mentioned sleeve member 21 which is tightly connected to inner cylindrical member 18, there is arranged an annular boot unit 23.
Inner cylindrical member 18 is made of a steel or the like and formed with a center through bore 18a into which the above mentioned smaller diameter right shaft portion 13 of input shaft 2 is inserted.
Center through bore 18a and right shaft portion 13 are connected through a spline coupling. For this spline coupling, center through bore 18a has a plurality of splines 24 and the right shaft portion 13 of input shaft 2 has a plurality of splines 15.
Inner cylindrical member 18 has a convex outer surface 18b on which balls 20 roll. The splined inner cylindrical wall 24 of center through bore 18a is, at a position near a right end thereof, with an annular groove 25 into which the above-mentioned snap ring 16 is tightly received upon proper coupling between input shaft 2 and the universal joint 3a.
As is seen from
If desired, sleeve member 21 may be integral with inner cylindrical member 18.
As is seen from 3, annular groove 25 is shaped to have a generally trapezoidal cross section. A depth “d” of annular groove 25 to a bottom wall 25a is determined about ⅖ of the diameter of snap ring 16. As shown, a right side wall 25b of annular groove 25 is perpendicular (viz., β=90 degrees) to bottom wall 25a and a left side wall 25c of annular groove 25 is inclined about 50 degrees (viz., α=50 degrees) relative to bottom wall 25a.
Accordingly, if a certain force is applied to input shaft 2 in a direction of the arrow “F” causing a leftward movement of the right shaft portion 13 and abutment of snap ring 16 with the inclined left side wall 25c of annular groove 25, snap ring 16 is forced to reduce its diameter permitting disengagement of input shaft 2 from inner cylindrical member 18, particularly from the splined center through bore 18a.
It is thus to be noted that annular groove 13b of input shaft 2, snap ring 16 and annular groove 25 of inner cylindrical member 18 constitute a positioning mechanism through which input shaft 2 can be axially positioned relative to first constant velocity universal joint 3a.
As is seen from
As is seen from
The above-mentioned annular boot unit 23 comprises an annular metal retainer 27 that has a right end fixed to outer cylindrical member 17, an annular boot 28 that has a larger diameter outer peripheral portion 28a fixed to a left end of annular metal retainer 27 and a fastening band 29 that is arranged to bind a smaller diameter inner peripheral portion 28b of annular boot 28 to sleeve member 21, as shown.
More specifically, as is seen from
Annular boot 28 is made of a rubber or plastic material and constructed to have a generally U-shaped cross section. As shown, when assembled, annular boot 28 is so oriented as to project its swelled portion toward balls 20.
Smaller diameter end portion 28b of annular boot 28 is formed with both an inner annular ridge (no numeral) that is tightly received in an annular groove 21b formed on sleeve member 21 and an outer annular groove 28d that tightly receives the above-mentioned annular band 29.
Due to provision of annular boot unit 23 and circular seal cap 22, a grease can be held in a space defined between outer and inner cylindrical members 17 and 18.
Although first constant velocity universal joint 3a is of a fixed type, it allows a slight swinging between input shaft 2 and drive shaft 4. Second constant velocity universal joint 5 (see
Third constant velocity universal joint 7 is substantially the same as the above-mentioned first constant velocity universal joint 3a, and thus description on the construction of the joint 7 will be omitted.
In the following, assembling steps for propeller shaft la and operation of first constant velocity universal joint 3a will be described with the aid of the drawings.
First, the work for assembling annular boot unit 23 will be described. That is, in a component factory, by using a common method, larger diameter outer peripheral portion 28a of annular boot 28 is connected to annular metal retainer 27 in the above-mentioned manner. Then, the base portion 27a of metal retainer 27 is tightly received in annular groove 17a of outer cylindrical member 17.
Then, smaller diameter inner peripheral portion 28b of annular boot 28 is disposed on the left end of sleeve member 21 and fastening band 29 is disposed on smaller diameter inner peripheral portion 28b of annular boot 28, and fastening band 29 is tightened in a known manner. With this, annular boot unit 23 is properly mounted to first constant velocity universal joint 3a.
In a vehicle body assembling factory, first constant velocity universal joint 3a and input shaft 11 are combined in the following manner.
That is, as is seen from
Under this sliding, snap ring 16 is kept compressed while pressing its outer portion against the splined inner cylindrical wall 24.
However, as is seen from
With the above-mentioned assembling steps, input shaft 2 and first constant velocity universal joint 3a are coupled together with the aid of the spline coupling effected by splines 15 and 24 and with the resilient engagement of snap ring 16 with annular groove 25. Of course, under this condition, unexpected disengagement of input shaft 2 from the universal joint 3a is suppressed.
That is, input shaft 2 and the universal joint 3a are operatively connected through the engagement between splines 15 and 24 and the engagement between snap ring 16 and annular groove 25. In other words, in the first embodiment of the invention, for operatively connecting input shaft 2 and the universal joint 3a, no bolts are used. That is, in this first embodiment, a torque transmission from input shaft 2 to drive shaft 4 is assuredly carried out without usage of any connecting bolts.
When smaller diameter right shaft portion 13 is sufficiently inserted into inner cylindrical member 18, snap ring 16 is brought into engagement with annular groove 25. Upon this, further axial movement of the right shaft portion 13 relative to inner cylindrical member 18 and thus relative to outer cylindrical member 17 is suppressed. That is, upon assembling, axial positioning of the right shaft portion 13 of input shaft 2 relative to outer cylindrical member 17 is assured.
As will be understood from the foregoing description, the engagement of snap ring 16 with annular groove 25 is effected by simply pushing input shaft 2 into inner cylindrical member 18. That is, the work for properly connecting input shaft 2 to the universal joint 3a is very easy.
As is seen from
Furthermore, since seal ring 14 is tightly held by annular groove 12a of the cylindrical outer surface of the intermediate portion 12 and arranged to seal an entirely outer surface of the intermediate portion 12 for its sealing area, seal ring 14 can exhibit a satisfied sealing performance.
Furthermore, since snap ring 16 is placed in the interior of outer cylindrical member 17 while keeping away from seal ring 14, snap ring 16 is sufficiently fed with the grease from the interior of outer cylindrical member 17, which suppresses corrosion of snap ring 16.
As is described hereinabove, in this first embodiment, the connection between input shaft 2 and first constant velocity universal joint 3a is made through the engagement between splines 15 and 24 and the catching or holding function of snap ring 16 without usage of conventional bolts. Accordingly, in this embodiment, reduction in component count is delivered and thus weight reduction of propeller shaft 1a and efficient assembly operations for vehicles are achieved. Furthermore, because of presence of seal ring 14, the above-mentioned dust-tight and grease holding performance is obtained.
Furthermore, as will be understood from
As will be understood from
Due to this leftward movement, snap ring 16 is brought into abutment with the inclined left side wall 24c of annular groove 25 and thus thereafter, the diameter of snap ring 16 is gradually reduced as snap ring 16 slides down on and along the inclined left side wall 25c in accordance with the leftward movement of input shaft 2. Once the leftward movement comes to a certain level, the diameter of snap ring 16 becomes sufficiently small to unlock the engagement between input shaft 2 and sleeve member 21, and thus, thereafter, input shaft 2 is instantly disengaged from first constant velocity universal joint 3a.
Referring to
Since this second embodiment is similar to the above-mentioned first embodiment, only parts or portions that are different from those of the first embodiment will be described in the following.
As is seen from
Because of usage of two seal rings 14 and 29, much effective sealing against muddy water, dusts or the like is obtained in this embodiment. Furthermore, due to provision of such two seal rings 14 and 29, undesired leakage of the grease from the interior of outer cylindrical member 17 to the outside is much assuredly suppressed.
Referring to
In this third embodiment, the axial length of medium diameter intermediate portion 12 of input shaft 2 is small as compared with those of the above-mentioned first and second embodiments.
Furthermore, in this third embodiment, a seal ring 31 is tightly received in an annular groove 30 that is formed on the smoothed inner cylindrical wall of sleeve member 21. In use, seal ring 31 is pressed against the cylindrical outer surface of medium diameter intermediate portion 12 of input shaft 2.
Referring to
In this fourth embodiment, an annular groove 32 is formed on and around a root portion of medium diameter intermediate portion 12 of input shaft 2, and a seal ring 33 is tightly received in annular groove 32. That is, when the right shaft portion 13 of input shaft 2 is properly set in inner cylindrical member 18, seal ring 33 is compressed between annular flat surface 11a of input shaft 2 and the tapered left end 21d of sleeve member 21, as shown.
With provision of seal ring 33, the clearance “C1” is directly sealed, and thus the interior of outer cylindrical member 17 is protected from the entry of muddy water, dusts or the like.
Referring to
In this fifth embodiment, an annular groove 34 is formed on annular flat surface 11a of input shaft and a seal ring 35 is tightly received in annular groove 34. That is, when the right shaft portion 13 of input shaft 2 is properly set in inner cylindrical member 18, seal ring 35 is compressed between a bottom wall of annular groove 34 and the left end of sleeve member 21, as shown.
Like in the above-mentioned fourth embodiment, the clearance “C1” is directly sealed, and thus, the interior of outer cylindrical member 17 is protected from the entry of muddy water, dusts or the like.
Referring to
In this sixth embodiment, the axial length of the smaller diameter right shaft portion 13 of input shaft 2 is longer than those of the above-mentioned embodiments. Thus, annular groove 25 used for limiting the axial movement of the right shaft portion 13 is placed at the right end of the center through bore 18a of inner cylindrical member 18.
Due to the longer construction of the right shaft portion 13, the mechanical strength of the portion 13 is increased and the engagement between splines 15 and 24 is much effectively made.
The entire contents of Japanese Patent Application 2012-66120 filed Mar. 22, 2012 are incorporated herein by reference.
Although the invention has been described above with reference to the embodiments of the invention, the invention is not limited to such embodiments as described above. Various modifications and variations of such embodiments may be carried out by those skilled in the art, in light of the above description.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012-066120 | Mar 2012 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 3822570 | Fisher | Jul 1974 | A |
| 4869556 | Gees | Sep 1989 | A |
| 7470198 | Cermak | Dec 2008 | B2 |
| 7677984 | Hahn et al. | Mar 2010 | B2 |
| 7712994 | Cermak | May 2010 | B2 |
| Number | Date | Country | |
|---|---|---|---|
| 20130252748 A1 | Sep 2013 | US |
