Patent Application
20100129245
The present invention relates in general to reciprocating pumps and, particular, to a floating pinion bearing for a reciprocating pump.
In oil field operations, reciprocating pumps are often used for various purposes. Some reciprocating pumps, generally known as “service pumps,” are typically used for operations such as cementing, acidizing, or fracing a well. Typically, these service pumps run for relatively short periods of time, but they operate on a frequent basis. Often they are mounted to a truck or a skid for transport to various well sites. A pump might operate several times a week. In many applications, several pumps are connected in parallel to a single flow line.
Referring to
As shown in
Near each end of shaft 27, a pinion bearing assembly 31 comprising an inner race 33, an outer race 35, and spherical bearings 37 is shrunk-fit around a desired portion of pinion shaft 27. Although referred to as “spherical,” bearings 37 are generally cylindrical, but with outward curved sides between its ends. A bearing housing 39 fits around the outer race 35 of bearing assembly 31. Bearing housing 39 contains a lip 43 around its outer surface that acts to capture bearing assembly 31 once bearing housing 39 is securely fastened to power frame housing 13. Bearing housing 39 is bolted to a frame housing 40 by bolts 42. Frame housing 40 is welded to power frame housing 13. An outer housing surrounds gears 24, 26 and is filled with a lubricating fluid.
Assembly and installation of the pinion 26, and in particular, the bearing housing 39 to power frame 13 requires hammering of the bearing housings 39 into the power frame 13. While doing so, bearing housing 39 may become misaligned with bearings 37. The installation process is time consuming and inefficient. Thus, an improved design for facilitating engagement between the various components of reciprocating pump assemblies is needed.
One embodiment of a floating pinion bearing for a reciprocating pump assembly includes a power frame that houses a crankshaft. The crankshaft is mechanically connected to a large gear or bull gear on each end that is in mechanical engagement with a small gear or pinion. A bearing housing is integrally formed as part of the power frame with an increased width and a constant inner diameter. A pinion bearing assembly comprising an inner race, an outer race, and spherical bearings is placed around the shaft of the pinion. A sleeve with a flange area is placed around the shaft and is placed in flush contact with the inner and outer races of the bearing assembly before being temporarily secured to the shaft. The pinion is installed in the reciprocating pump assembly such that the bearing assembly rests on the bearing housing which is integrally formed as part of the power frame. The sleeve is then removed from the shaft. The bearing assembly is free to float on the bearing housing and provides for some lateral movement of the shaft and bearing assembly during operation of the reciprocating pump assembly. The bull gears on opposite ends have helical teeth aligned opposite each other. The teeth create resultant forces on the pinion teeth to maintain it centered.
The foregoing and other objects and advantages of the present invention will be apparent to those skilled in the art, in view of the following detailed description of the present invention, taken in conjunction with the appended claims and the accompanying drawings.
So that the manner in which the features and advantages of the invention, as well as others which will become apparent are attained and can be understood in more detail, more particular description of the invention briefly summarized above may be had by reference to the embodiment thereof which is illustrated in the appended drawings, which drawings form a part of this specification. It is to be noted, however, that the drawings illustrate only an embodiment of the invention and therefore are not to be considered limiting of its scope as the invention may admit to other equally effective embodiments.
Pump 12 of this invention has the same general components as described in connection with
An installation tool or sleeve 45 is used to install pinion 26 and pinion bearing assembly 31. Sleeve 45 contains a plurality of set screws 47 that extend through the sleeve and engage the teeth on pinion 26 in order to secure the position of sleeve 45 around pinion 26. Sleeve 45 has a flange area 49 on one of its ends. Flange area 49 has an outer diameter preferably equal to or greater than that of the outer race 35 outer diameter.
Referring to
During operation of the reciprocating pump assembly 12, bull gears 24 do not move laterally, but pinion shaft 27 is free to float or move laterally. Bearing assemblies 31 are fixed to pinion shaft 27 and float with it. The pinion bearing assemblies 31 are free to float axially or laterally on bearing housings 41. During operation, bearing assemblies 31 thus move laterally in unison with pinion 26 and shaft 27. The engagement of bull gears 24 and pinions 26 prevents pinion bearing assembly 31 from leaving the bearing housing 41, as the maximum axial movement allowed in one embodiment is 0.250 inches, but that maximum may be varied.
The invention has several advantages. By eliminating the outer bearing housing, the installation time of the pinion and pinion bearing assembly is reduced. Additionally, the incorporation of the bearing housing as an integral part of the power frame housing helps to transfer the load from the pinion to the power frame as the complete width of the bearing and power frame are in contact at all times.
While the invention has been shown or described in only some of its forms, it should be apparent to those skilled in the art that it is not so limited, but is susceptible to various changes without departing from the scope of the invention.
