The field of the present invention is that of interaxle differentials for vehicles having at least two powered axles. More particularly, the present invention relates to a torsional lock for locking the output shafts of a differential, especially differentials used in classes 7 and 8 large truck vehicles.
Differential gear mechanisms, commonly referred to as differentials, are well known devices which are frequently used in the drive train axle systems of most vehicles. The differential is usually connected between an input drive shaft (typically a drive shaft from the vehicle engine/transmission) and a pair of output shafts (typically a pair of axle half shafts connected to the vehicle wheels). The differential distributes torque from the input shaft equally to the two output half shafts, while permitting such output half shafts to rotate at different speeds under certain conditions. As a result, torque is supplied to both wheels of the vehicle as it negotiates a turn, while permitting the outside wheel to turn faster than the inside wheel.
Many tractors have a drive train which includes two drive axles wherein each drive axle includes two half shafts. Each half shaft is supported on a pair of double wheels and a differential is provided for each axle between the left and right half shafts. Between the pair of front and rear axle shafts, is a power dividing or interaxle differential, provided to ensure that generally equal amounts of torque are distributed to the front and rear drive axles and to accommodate any unequal amounts of rotation of the vehicle wheels (tires) with the road.
During hazardous driving conditions, many truck operators find it desirable to lock the differential between the two drive axles. Accordingly, many truck differentials provide an interaxle lock that torsionally locks the front and rear drive axles together.
The power train rearward of the engine/transmission is commonly called the tandem axle assembly. The tandem axle assembly has a front axle casing and a rear axle casing. The front axle casing mounts a ring gear. The ring gear mounts a differential carrier that powers the front drive half axles. The ring gear is rotated by a pinion gear mounted on a counter shaft. The counter shaft on its opposite end has a driven (sometimes referred to as a counter) spur or helical gear which is splined thereon.
The driven gear is rotated by a helical side gear. The helical side gear is rotatably mounted by a front or first input shaft that is torsionally connected with a transmission output shaft. The first input shaft is connected to a cross member (commonly referred to as a differential spider) upon which are bevel gears that mesh with the helical side gear. The spider is also in mesh with a second side gear which is torsionally connected with an axially aligned second shaft which is associated (by yoke) with an input shaft for the rear drive axle input shaft.
Torsionally fixed on but axially slidably mounted on the first input shaft is a sliding clutch gear. The sliding clutch gear can be moved by a shift fork to lock with the helical side gear thereby locking the helical side gear with the first axle input shaft and thereby locking the front and rear drive axles of the tractor axle assembly together. To move the clutch gear between its unlocked and locked position there is provided a shift fork.
Utilization of the shift fork has been satisfactory, however, the utilization of the shift fork requires more space within the front axle casing than what is desired and causes wear of the shift fork, especially attributable to its offset mounting. Additionally, force application on the clutch gear is more uneven than optimally desired. It is desirable to provide an improved interaxle differential lock which is superior to those available in the past and eliminate the utilization of the shift fork.
To make manifest the above noted desires a relevation of the present invention is brought forth. In a preferred embodiment, the present invention brings forth a differential for an axle assembly with an interaxle differential for a vehicle having at least first and second drive axles. The arrangement includes a casing and a ring gear rotatably mounted within the casing. A counter shaft with an input pinion is provided rotatably mounted within the casing. The counter shaft first end has the pinion which is meshed with the ring rear.
A driven gear is mounted on a second end of the counter shaft. The driven gear is meshed with the helical side gear. The helical side gear is rotatably mounted on a front or first axle input shaft adjacent a first or rear end thereof. A spider is connected on the rear end of the first axle input shaft having bevel gears meshed with the helical side gear. A second axle input shaft is axially aligned with the first axle input shaft. A second side gear is connected on the second axle input shaft and is in mesh with the spider. A clutch gear is torsionally locked on the first axle input shaft and is axially slidably mounted thereon for selective engagement with the helical side gear.
A fluid-actuated annular piston is provided which is mounted in the casing. The annular piston is provided to urge the clutch gear into engagement with the helical side gear that torsionally locks the first and second axle input shafts together. A spring is provided to urge the clutch gear to the unlocked position on the first axle input shaft.
It is a desire of the present invention to provide an arrangement of an axle assembly with an interaxle differential for a vehicle having first and second drive axles having an annular piston which urges a clutch gear into engagement with a helical side gear to lock first and second axle input shafts torsionally together.
Other features and desires of the present invention can be further realized from a review of the accompanying drawings and detailed description.
Referring to
A spider 50 has a splined connection with the rear extreme end of the first axle input shaft 44. The spider 50 has bevel pinions 52 which are in a mesh relationship with the side gear 42. The bevel pinions 52 are also meshed with a rear bevel side gear 54. The side gear 54 is torsionally locked onto the second or rear axle input shaft 60. The second axle input shaft (sometimes referred to as the output shaft) 60 is mounted in its rear end in the casing 10 by thrust bearings 62, 64. A rear end 68 of the second axle input shaft 60 is connected via a yoke and a universal joint connected drive shaft (not shown) with a shaft 70 having a gear 72 which is in turn meshed with a pinion 74 which turns a ring gear 76 which drives the rear axle halves in a manner similar to that previously described for the front ring gear 14 and the front half shafts 20.
Axially slidably mounted on the front axle input shaft 44 is a sliding dog clutch gear 80. The clutch gear 80 is axially positioned on the front axle input shaft 44 by a fork 82. A mechanism (not shown) is provided for moving the fork while retaining the fork in a desired axial position with respect to the front axle input shaft 44. When it is desired to lock the front axle input shaft 44 with the rear axle input shaft 60, the fork 82 moves the clutch gear 80 rearward to lock in position with the side gear 42. The locking of the clutch gear 80 with the side gear 42 causes the clutch gear 80, side gear 42, spider 50, side gear 54 and rear axle output shaft 60 to rotate in unison and effectively eliminate the differential which typically exists between the front axle input shaft 44 and the rear axle output shaft 60.
Referring to
A bevel spring 104 juxtaposed between a leg 106 of the casing and the piston 90 biases the piston 90 to its forwardmost position. The piston 90 also has a series of geometrically spaced forward extending fingers 108 having a hook 110 which extend into a fork groove 112 of the clutch gear 80. To engage the clutch gear 80 with the side gear 42, the chamber 100 is pressurized and the piston 90 is actuated rearward causing a contact portion 114 to push the clutch gear 80 into engagement with the side gear 42. Upon depressurization of the chamber 100, the piston 90 will be pushed back by the bevel spring(s) 104 causing the hook 110 captured within the fork groove 112 to pull the clutch gear 80 out of engagement with the clutch groove. Typically the piston will be flexible enough so that upon initial assembly the hooks 110 will be forward of a forward end of the clutch gear and pressurization of the chamber 100 will cause the hook and fingers 108 to flex upwards and then snap down into position.
Referring to
Referring to
Referring to
Referring to
Referring to
While the invention has been described in connection with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.
Number | Name | Date | Kind |
---|---|---|---|
2132692 | Lawrence | Oct 1938 | A |
3146842 | Nelson et al. | Sep 1964 | A |
3460404 | Schmid | Aug 1969 | A |
3915032 | Ottemann | Oct 1975 | A |
3916278 | Currell et al. | Oct 1975 | A |
4037696 | Shealy | Jul 1977 | A |
4042080 | Nelson | Aug 1977 | A |
4050534 | Nelson et al. | Sep 1977 | A |
4194586 | Hicks | Mar 1980 | A |
4263824 | Mueller | Apr 1981 | A |
4432431 | Russell | Feb 1984 | A |
4582160 | Weismann et al. | Apr 1986 | A |
4671135 | Dangel | Jun 1987 | A |
4715248 | Gant | Dec 1987 | A |
4733578 | Glaze et al. | Mar 1988 | A |
5099944 | Kageyama et al. | Mar 1992 | A |
5123513 | Petrak | Jun 1992 | A |
5176591 | Krisher | Jan 1993 | A |
5267489 | Ziech | Dec 1993 | A |
5273499 | Friedl et al. | Dec 1993 | A |
5299986 | Fabris et al. | Apr 1994 | A |
5320586 | Baxter, Jr. | Jun 1994 | A |
5353890 | Clohessy | Oct 1994 | A |
5370018 | Kwasniewski | Dec 1994 | A |
5386898 | Weilant et al. | Feb 1995 | A |
5503602 | Dick | Apr 1996 | A |
5591098 | Jones et al. | Jan 1997 | A |
5860889 | Schlosser et al. | Jan 1999 | A |
6368072 | Inoue et al. | Apr 2002 | B1 |
6422128 | Ahn | Jul 2002 | B1 |
6464053 | Hoebrechts | Oct 2002 | B1 |
6467592 | Dernebo | Oct 2002 | B1 |
6648788 | Sullivan | Nov 2003 | B1 |
Number | Date | Country |
---|---|---|
2789739 | Aug 2000 | FR |
06081903 | Mar 1994 | JP |
Number | Date | Country | |
---|---|---|---|
20040087408 A1 | May 2004 | US |