Hydraulically Actuated Cone Clutch

This invention relates generally to clutches, and more particularly concerns cone clutches of the hydraulic type.

Cone clutches have found wide application in machinery where it may be desired to disengage one powered function while still driving a transmission or input shaft. Industrial drives of all sorts, particularly those having multiple output shafts, off-road vehicles and the like have utilized such clutches.

In the past, these cone clutches have usually been constructed so that they are engaged by operating some mechanical linkage mechanism, and have been disengaged by hydraulic means.

It is the general object of the present invention to provide a hydraulic clutch which is positively engaged by hydraulic means, and can be disengaged by mechanical means. An associated general object is to provide such a cone clutch which is inexpensive to manufacture, yet which is reliable and rugged in operation.

A more specific object is to provide such a cone clutch in which the number of parts required for complete assembly are minimized. It is a correlated object to provide a cone clutch in which the female cone member and the output shaft member are fabricated as one, unitary, single piece.

Another object is to provide a cone clutch which includes means for positively urging apart the mating cone clutch members when disengagement is desired. An associated object is to provide such a cone clutch in which a sliding cone member is slidably connected to one shaft (here, the input shaft) by an inexpensive yet reliable and rugged mechamism.

Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings. Throughout the drawings, like reference numerals refer to like parts.

FIG. 1 is an end elevational view of a clutch embodying the present invention; and

FIG. 2 is a sectional view taken substantially in the planes of line 2--2 in FIG. 1.

While the invention will be described in connection with a preferred embodiment, it will be understood that it is not intended to limit the invention to this embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.

Turning more specifically to the drawings, there is shown a clutch 10 embodying the present invention. Viewed generally, this clutch 10 includes mating housing members 11 and 12 secured together by bolts 13. Fluid leakage around the bolts 13 and between the housing members 11 and 12 can be prevented by suitably-sized and installed O-rings 14.

Protruding from the clutch unit 10 is an input shaft 16, the end of which is here provided with splines 17 for connection to a suitable drive device (not shown). An appropriate ball or other bearing 19 journals the shaft 16 within one member 12 of the housing. Snap rings 20 and 21 secure one portion of the bearing assembly 19 within the housing 12 and the shaft 16 to another part of the bearing 19. A seal member 23 of suitable design discourages fluids within the clutch 10 from leaking out, and bars the ingress of dirt or other foreign matter.

At the other end of the clutch 10, an output shaft 26 is provided with a splined female recess 27 which can be connected to a transmission or like structure to be driven so that the transmission and the clutch can, if desired, have a common oil circulatory system. This output shaft 26 is journalled upon the housing member 11 by a suitable bearing assembly 28. A snap ring 29 secures one portion of the bearing 28 to the output shaft 26; a similar snap ring 30 secures another portion of the bearing 28 to the stationary housing member 11. To provide a compact unit, and to reduce the number of parts required in the clutch mechanism, a third, internal bearing assembly 33 insures that the input shaft 16 and the output shaft 26 are axially aligned, provides additional bearing support to both shafts 16 and 26, and permits the input shaft 16 to rotate freely yet independently of the output shaft 26 when desired.

In accordance with the invention, a positive, hydraulically actuated system is provided for engaging the clutch and causing the output shaft 26 to rotate together with the input shaft 16. When clutch operation is desired--that is, when an operator wishes to transmit rotary motion from the input shaft 16 to the output shaft 26--suitably pressurized fluid is introduced to an input port 35 and is directed, by one or more appropriate passages 36, to an annular hydraulic chamber 37. This fluid forces an annular piston 39 outwardly, or, as illustrated in FIG. 2, to the left. Fluid leakage from the chamber 37 around the piston 39 can be prevented by suitable O-rings 40 and 41. A suitably plugged drain 42 permits fluid to be drained from the chamber 37 for servicing.

In accordance with another aspect of the invention, positive, fail-safe type mechanical means are provided for urging the clutch into a disengaged position. To accomplish this, it will be noted that the above-discussed outward or leftward motion of the piston 39 has caused similar leftward motion to an annular thrust plate 44. Oil circulation grooves 45 encourage good lubrication throughout adjacent portions of the clutch. Precision in thrust plate motion is provided by mounting the thrust plate 44 upon a series of pins 46 carried for reciprocation in mating bores 47 formed in the housing member 12. Pre-compressed coil springs 49 surround a portion of the pin, and abut a stationary member such as the opposite housing member 11. Thus, when the positive hydraulic pressure experienced in the hydraulic chamber 37 is released, the action of the return springs 49 urges the thrust plate 44 and the hydraulic piston 39 to the right, as shown in FIG. 2, and back into their respective inactive, clutch-disengaged positions.

Alternatively, a series of spot-type pistons can be provided in place of the annular piston 39. Preferably, these spot pistons are equiangularly spaced about the input shaft 16 so as to provide a uniform pressure against the annular thrust bearing plate 44.

A female clutch member 50 is provided with a conically shaped annular inner surface 51. It will be noted that, in accordance with yet another aspect of the invention, this female clutch member 50 is formed as an integral, single piece with the output shaft 26 so as to lower the cost of clutch manufacturing.

A mating, male clutch member 52 is provided with a suitably grooved or otherwise finished annular outer surface 53 adapted for mating with the female clutch surface 51. This male cone member 52 is secured upon the input shaft 16 for rotation therewith, but is permitted limited axial motion relative thereto. To urge the male cone member 52 into driving engagement with the female clutch member 50, a roller bearing mechanism 55 or other suitable device is interposed between the non-rotating thrust plate 44 and the rotating male cone member 52. This device transmits axial engagement or leftward motion of the piston 39 and thrust plate 44 to the male cone member 52 and urges the male cone member 52 likewise to the left as viewed in FIG. 2.

In accordance with still another aspect of the invention, this cone member 52 is caused to rotate with the input shaft 16, but is permitted limited axial motion relative thereto by an inexpensive, yet reliable and rugged device. Here, the cone member-shaft interconnector takes the form of a series of cylindrical spline pins 60 which are carried in mating grooves of semi-circular cross-sectional aspect 61 formed in a radially extending mounting flange 63 of the input shaft 16, and similar grooves 62 of semi-circular cross-sectional aspect are formed in the male cone member 52. An abutment 65 is formed at the tip of the input shaft 16 to prevent excessive pin motion to the left as viewed in FIG. 2; a similar abutment 66 is formed at the opposite end of each groove 62 in the male member cone member 52 to prevent excessive pin motion in the opposite direction. Thus, these pins 60 key the male cone member 52 to the input shaft 16, but permit limited relative axial motion. This arrangement is of surprisingly reliable and rugged construction; yet it is relatively inexpensive and permits the transfer of large amounts of torque from the input shaft 16 to the output shaft 26 without damage or destruction. In the illustrated embodiment, three such pins 60 are provided at equiangularly spaced positions about the circumference of the shaft flange 63, as can be envisioned from FIG. 1.

In carrying out the invention, the clutch is positively returned to a clutch-deenergized or deactivated position by positive mechanical means. Here, a series of equiangularly spaced resilient coil spring members 70 are received in opposing wells 71 and 72 formed in the input shaft flange 63 and in the male cone member 52, respectively. When hydraulic pressure is released, these pre-compressed springs 70 axially expand, forcing the male cone member 52 to the right and out of engagement with the female cone portion 50 of the output shaft 26.

It will be noted that the stop pin 46 is provided with a nose 76 of pre-determined length for abutment against the opposite housing member 11 so as to limit the travel of the pin 46, and consequently limit the amount of engagement motion which can be imparted by the piston 39 via the thrust plate 44 and to the male cone member 52. In this way, the male cone member 52 can be pushed firmly into driving engagement with the female cone member 50, but excessive axial motion and force is not imparted to the output shaft 26, and damage to the clutch unit bearings or other associated parts is avoided.