This invention relates to a combine head, comprising a
frame; an end wall coupled to said frame; a plurality of row units coupled to said
frame; a first driveshaft drivably coupled to said plurality of row units; and a
drive system including a first drive assembly, wherein said first drive assembly
is coupled to said end wall and coupled to said first driveshaft, said first drive
assembly including a first bearing and a first sprocket, said first bearing rotatably
supporting said first driveshaft, said first bearing defining a first rotational
axis of said first driveshaft, and having a first plane passing radially through
said first bearing perpendicular to said first rotational axis, said first sprocket
being drivably coupled to said first driveshaft, said first sprocket having a first
plurality of teeth located around a perimeter of said first sprocket.
A combine head according to the preamble of claim 1 is
described for example in
EP 0 491 405 A
In the prior art, as illustrated in Fig. 1, a drive system
10 includes a pair of elongated driveshafts 12, 14 that are arranged to be substantially
parallel. Each of driveshafts 12, 14 are rotatably coupled to a frame member 16
via a respective bearing 18, 20. Coupled to the ends of driveshafts 12, 14, is a
respective sprocket 22, 24, which are drivably coupled by a chain (not shown) in
a manner as is well known in the art. In this prior art arrangement, the teeth of
sprockets 22, 24 are cantilevered outward on respective driveshafts 12, 14 with
respect to bearings 18, 20. Accordingly, for example, under the high loads that
drive the row units of a corn head via sprockets 22, 24, this prior art arrangement
results in forces in directions F1 and F2, and in turn results in the flexing of
driveshafts 12, 14, as illustrated by curved lines C1 and C2. As a result of the
flexing of driveshafts 12, 14, the chains that drive, or are driven by, the driveshafts
12, 14 are bent and wear rapidly.
What is needed, therefore, is an improved combine row unit
drive system that is more rigid and reduces wear on the sprockets and chains.
This object is achieved with the subject matter of claim
1. The dependent claims recite advantageous embodiments.
The invention is directed to a combine head. The combine
head includes a frame, and an end wall coupled to the frame. A plurality of row
units is coupled to the frame. A driveshaft is drivably coupled to the plurality
of row units. A drive system includes a drive assembly. The drive assembly is coupled
to the end wall and is coupled to the driveshaft. The drive assembly includes a
bearing and a sprocket. The bearing rotatably supports the driveshaft, and defines
a rotational axis of the driveshaft. A plane passes radially through the bearing
perpendicular to the rotational axis. The sprocket is drivably coupled to the driveshaft.
The sprocket has a plurality of teeth located around a perimeter of the sprocket,
wherein the plurality of teeth is located so that the plane passes radially through
the plurality of teeth.
The above-mentioned and other features and advantages of
this invention, and the manner of attaining them, will become more apparent and
the invention will be better understood by reference to the following description
of an embodiment of the invention taken in conjunction with the accompanying drawings,
- Fig. 1 is a top view of prior art driveshafts illustrating the tendency of the
shafts to flex under high loads.
- Fig. 2 is a perspective view of a combine and a combine head, with the combine
head being configured in accordance with an embodiment of the present invention.
- Fig. 3 is a bottom perspective view of the combine head of Fig. 2.
- Fig. 4 is a perspective view of the frame and end walls of the combine head
of Fig. 3.
- Fig. 5 is an exploded view of a drive assembly of the combine head of Fig. 2.
- Fig. 6 is an assembled section view of the drive assembly of Fig. 5 taken along
plane 6-6-6-6 of Fig. 5
Corresponding reference characters indicate corresponding
parts throughout the several views. The exemplifications set out herein illustrate
an embodiment of the invention, in one form, and such exemplifications are not to
be construed as limiting the scope of the invention in any manner.
Referring now to the figures, and particularly Fig. 2,
there is shown a combine 50 and a combine head 52. Fig. 2 is oriented with respect
to a common orthogonal coordinate system in which the X-axis extends from the origin
toward the rear of the combine and/or combine head in a longitudinal direction,
the Z-axis extends from the origin vertically, and the Y- axis extends from the
origin laterally, e.g., rightwardly, or orthogonal to the other two axes, across
the combine and/or combine head.
Combine 50 includes a feeder house 54 that extends from
the front of combine 50. A front end 56 of feeder house 54 is configured to support
combine head 52 in a manner known in the art. Combine head 52 defines a rectangular
aperture or opening 58 that receives front end 56 of feeder house 54 as combine
head 52 is mounted on combine 50 in a manner known in the art.
Referring also to Figs. 3 and 4, combine head 52, such
as a corn head in the embodiment shown, includes a combine head frame 100 to which
a plurality of row units 102, e.g., corn head units, is coupled, e.g., by bolts
and brackets. Each row unit of the plurality of row units 102 includes harvesting
components 103, such as for example a pair of stalk rolls, gathering chains, etc.,
associated with each individual row unit for gathering crops.
Combine head 52 also includes two row unit drive systems,
a drive system 104-1 and a drive system 104-2, which may be substantially identical
in configuration. Drive system 104-1 is configured to drive row units 102-1 of the
plurality of row units 102 generally on the left side of combine head 52 and the
other drive system 104-2 is configured to drive row units 102-2 of the plurality
of row units 102 generally on the right side of combine head 52.
As illustrated in Figs. 3-5, each drive system 104-1, 104-2
includes a first driveshaft 106 for driving the row units 102 that extends through
and is supported by the end sheet, or end wall, 108 of combine head 52. Row unit
driveshaft 106 is drivably coupled to the plurality of row units 102, and more particularly,
to the harvesting components 103 of the plurality of row units 102. With respect
to each drive system 104-1, 104-2, a sprocket 110 is fixed to the end of each driveshaft
106. A plurality of teeth 110-1 is located around a perimeter of sprocket 110. A
second sprocket 114 is supported on a second driveshaft 116 that extends through
end wall 108 of combine head 52. A plurality of teeth 114-1 is located around a
perimeter of sprocket 114. The outer perimeter of sprockets 110, 114 may be, but
need not be, the same. For example, the number of the plurality of perimetrical
teeth 110-1 may be, but need not be, the same as the number of the plurality of
perimetrical teeth 114-1.
A chain 112 engages the teeth 110-1 of sprocket 110 and
the teeth 114-1 of sprocket 114, and extends from sprocket 110 backward to sprocket
114, to drivably couple sprocket 110 to sprocket 114. An idler sprocket assembly
118 is attached to end wall 108, and provides adjustable tensioning of chain 112.
A cover/chain guard 120 is provided to cover chain 112 and sprockets 110, 114, and
is attached to end wall 108.
In an alternative arrangement, these drive system components
may be configured to drive all of the plurality of row units 102 using only one
of the drive systems 104-1, 104-2. In this arrangement, a single drive system (e.g.,
either the left side drive system 104-1 or the mirror image right side drive system
104-2) is provided to drive all of the plurality of row units 102 using a lengthened
driveshaft 106 that extends all the way across combine head 52 and is coupled to
all of the plurality of row units 102.
Each driveshaft 106 and driveshaft 116 is rotatably mounted
in position relative to end wall 108 of combine head 52 by a respective first drive
assembly 122-1 and a second drive assembly 122-2 that may be at least partially
preassembled prior to attachment to end wall 108 of combine head 52.
Referring to Figs. 5 and 6, each drive assembly 122-1,
122-2 includes, for example, a bearing housing 124, a bearing 126, a hub 128, a
seal 130, an O-ring 132, an outer snap ring 134, and an inner snap ring 136, as
well as a respective sprocket 110 or 114. The drive assembly 122-1 will be described
in more detail below, but it is to be understood that drive assembly 122-1 may be
representative of the configuration of drive assembly 122-2 as well. For example,
in the embodiment of Fig. 5, drive assembly 122-1 and drive assembly 122-2 may be
identical, or may be scaled differently (e.g., different sizes of bearings, hubs,
etc.), depending on the application. However, in the embodiment of Fig. 5, the structural
configuration of drive assembly 122-1 and drive assembly 122-2 is the same.
With respect to drive assembly 122-1, when assembled, bearing
126 defines a rotational axis 138-1 of hub 128 and sprocket 110, which in turn is
the rotational axis of driveshaft 106. In other words, bearing 126 is coaxial with
hub 128 along axis 138-1. Teeth 110-1 of sprocket 110 are aligned along a plane
140 passing radially through bearing 126 relative to axis 138-1, i.e., perpendicular
to axis 138-1. In other words, plane 140 is perpendicular to axis 138-1 and passes
radially through both bearing 126 and all of the plurality of teeth 110-1 of sprocket
110. Likewise, with respect to drive assembly 122-2, when assembled, bearing 126
defines a rotational axis 138-2 of hub 128 and sprocket 114, which in turn is the
rotational axis of driveshaft 116.
Bearing 126 may be, for example, a sealed bearing having
an outer race 142 and an inner race 144, and a plurality of ball bearings 146 located
between outer race 142 and inner race 144.
Bearing housing 124 includes a first bore 148, a second
bore 150, and a snap ring groove152. A diameter of first bore 148 is selected to
accommodate the outer race 142 of bearing 126 in a snug press fit to mount bearing
126 to bearing housing 124. A diameter of second bore 150 is selected to accommodate
seal 130 in a snug press fit. First bore 148 defines a bearing seat 154 at the end
of the axial extent of first bore 148 along axis 138-1. Snap ring groove 152 is
formed in first bore 148 to be axially separated from bearing seat 154 by a distance
corresponding to a thickness of outer race 142 of bearing 126 (i.e., in the direction
of axis 138-1). Second bore 150 defines a seal seat 156 at the end of second bore
150 along axis 138-1.
Hub 128 includes a stub portion 158 and a shoulder 160
extending radially outward from stub portion 158. Shoulder 160 has an outer surface
162 for mating to a sprocket, e.g., sprocket 110 in this example, and an inner surface
defining a bearing seat 164. A snap ring groove 166 is formed in an outer surface
168 of stub portion 158 to be axially separated from bearing seat 164 by a distance
corresponding to a thickness of the inner race 144 of bearing 126 (i.e., in the
direction of axis 138-1)
An axial opening 170 is formed in and extends through hub
128 at a central region 172 of stub portion 158 along axis 138-1. The shape of axial
opening 170 in a direction parallel to plane 140, i.e., perpendicular to axis 138-1,
corresponds to the shape of the outer surface of the shaft, e.g., driveshaft 106
or 116, to be inserted into axial opening 170. The shape may be, for example, polygonal
(e.g., hexagonal) to ensure that hub 128 and the inserted shaft rotate together
coaxially about axis 138-1.
In assembling drive assembly 122-1 or 122-2, seal 130 is
inserted in a press (snug) fit into second bore 150 of bearing housing 124. Stub
portion 158 of hub 128 is inserted in a snug fit into the inner race 144 of bearing
126 until inner race 144 engages bearing seat 164, and inner snap ring 136 is installed
in snap ring groove 166 on stub portion 158 of hub 128. Outer race 142 of bearing
126 is pressed into first bore 148 of bearing housing 124 until outer race 142 engages
bearing seat 154, and outer snap ring 134 is installed in snap ring groove 152.
Outer snap ring 134 is installed at the outer side of bearing 126 to prevent axial
movement of bearing 126 relative to bearing housing 124 along respective axis 138-1
(or axis 138-2). Inner snap ring 136 is installed at the inner side of bearing 126
to prevent axial movement of hub 128 relative to bearing 126 along the respective
axis 138-1 (or axis 138-2).
The example that follows describes the mounting of the
preassembled drive assembly 122-1 with specific reference to driveshaft 106. However,
it is to be understood that the principles of assembly and operation relative to
drive assembly 122-1 and driveshaft 106 may be applied to drive assembly 122-2 and
driveshaft 116, as well as any other similar configured drive assembly/driveshaft
Referring to Fig. 5, an end portion 174 of driveshaft 106
is inserted into axial opening 170 of hub 128 of drive assembly 122-1. Drive assembly
122-1 is then mounted to end wall 108, e.g., by one or more carriage bolts (not
shown) passing through a respective opening in end wall 108 and through a corresponding
opening in bearing housing 124, and threaded with a corresponding nut. At this time,
end portion 174 of driveshaft 106 will be substantially flush with outer surface
162 of hub 128. Also, driveshaft 106 is now rotatably supported by bearing 126 at
rotational axis 138-1, which in turn becomes the rotational axis of driveshaft 106.
O-ring 132 is installed in an O-ring groove formed in the outer surface 162 around
axial opening 170. Sprocket 110 is coupled to end portion 174 of driveshaft 106
by an axially extending fastener, e.g., bolt 176, and sprocket 110 is coupled to
shoulder 160 of hub 128 by a fastener, e.g., a ring of bolts 178. Another drive
assembly 122-2 is similarly installed with respect to driveshaft 116 and sprocket
114, if not already installed. Chain 112 is installed over teeth 110-1 of sprocket
110 and teeth 114-1 of sprocket 114 to drivably couple drive assembly 122-1 to drive
assembly 122-2, and the tension of chain 112 is adjusted by idler sprocket assembly
118. Cover/chain guard 120 may then be installed over chain 112, and attached by
fasteners, e.g., screws or bolts, to end wall 108.
As best shown in Figs. 5 and 6, each of sprockets 110,
114 has a dished, i.e., domed, shape that defines an interior recess 180 having
a depth 182. Interior recess 180 may, for example, have a substantially concave
shape. In other words, sprocket 110 has a dished shape to axially offset the plurality
of teeth 110-1 from an axial outer portion 110-2 of sprocket 110. Likewise, sprocket
114 has a dished shape to axially offset the plurality of teeth 114-1 from an axial
outer portion 114-2 of sprocket 114 along axis 138-1. As such, as illustrated in
Fig. 6, at least a portion of bearing 126, for example a substantial portion in
the present embodiment, is located within interior recess 180 of the respective
sprocket, e.g., sprocket 110.
As best shown in Fig. 6, for sprocket 110, depth 182 is
selected such that plane 140 radially passes both through all the perimetrical teeth
110-1 of sprocket 110 and through the axial center of bearing 126 (i.e., along axis
138-1) that supports sprocket 110 for rotation. Likewise, for sprocket 114, depth
182 is selected such that plane 140 passes radially through both all the perimetrical
teeth 114-1 of sprocket 114 and through the axial center of bearing 126 (i.e., along
axis 138-2) that supports sprocket 114 for rotation.
The load on each sprocket 110, 114 is resisted by an opposing
force applied by the respective bearing 126 in the same plane 140 perpendicular
to the axis of rotation of the respective driveshaft 106, 116 (i.e., axis 138-1,
138-2, respectively). In comparison to the prior art configuration of Fig. 1, the
configuration of sprocket 110 and its drive assembly 122-1 reduces the moment applied
to the shaft 106 by sprocket 110 at the respective bearing 126 by applying loads
to driveshaft 106 directly in the plane 140 of bearing 126, i.e., at different locations
along driveshaft 106 than that of the configuration of Fig. 1. Similarly, the configuration
of sprocket 114 and its drive assembly 122-2 reduces the moment applied to driveshaft
116 by sprocket 114 at the respective bearing 126 by applying loads to driveshaft
116 directly in the plane 140 of bearing 126, i.e., at different locations along
driveshaft 116 than that of the configuration of Fig. 1. This reduces the bending
moment on the respective driveshaft, which in turn reduces the resultant misalignment
of the sprockets 110, 114 under heavy loads and the concomitant flexure and undue
wear of chain 112.