Patent Application
20220185398
The present disclosure relates generally to a suspension and drive system for a machine and, for example, to a torsion axle arrangement within a suspension and drive system.
A mobile machine (e.g., a skid steer loader, an excavator, a bulldozer, and/or the like) includes a chassis that supports an engine and an undercarriage that transfers power from the engine to a ground surface. In some instances, the undercarriage may be rigidly mounted to the chassis. As a result, the machine may transfer loads and vibrations to an operator, making long periods of machine usage uncomfortable for the operator. Furthermore, such a rigid mounting may cause the undercarriage to lift off of the ground surface, thereby reducing traction, steering control, and stability of the machine.
U.S. Pat. No. 8,360,179, which issued to Daniels et al. on Jan. 29, 2013, discloses a suspension system for a machine. The suspension system includes a front torsion axle assembly having a first shaft, a first arm connected at a first end to the first shaft, and a first axle connected to a second end of the first arm and extending from the first arm in a direction opposite the first shaft. The suspension system also includes a rear torsion axle assembly having a second shaft, a second arm connected at a first end to the second shaft, and a second axle connected to a second end of the second arm and extending from the second arm in a direction opposite the second shaft. The suspension system further includes a frame configured to support an engine and being connected to an end of the first shaft and an end of the second shaft. The second ends of the first and second arms are oriented within common angular quadrants defined by a coordinate system having an axis passing through the first ends of the first and second arms and aligned with a travel direction of the machine.
The suspension and drive system of the present disclosure solves one or more of the problems set forth above and/or other problems in the art.
In some implementations, a suspension and drive system for a machine includes a chassis configured to support an engine of the machine; a front torsion axle assembly including: a front axle, a front shaft that extends through a front end of the chassis, and a front arm connecting an end of the front axle to an end of the front shaft; and a rear torsion axle assembly including: a rear axle, a rear shaft that extends through a rear end of the chassis, and a rear arm connecting an end of the rear axle to an end of the rear shaft; and wherein the front torsion axle assembly and the rear torsion axle assembly together define a quadrilateral, wherein a center of the front axle defines a first vertex of the quadrilateral, a center of the front shaft defines a second vertex of the quadrilateral, a center of the rear shaft defines a third vertex of the quadrilateral that is opposite the first vertex, and a center of the rear axle defines a fourth vertex of the quadrilateral that is opposite the second vertex, wherein a rear interior angle of the quadrilateral at the fourth vertex is less than a front interior angle of the quadrilateral at the second vertex.
In some implementations, a suspension and drive system for a machine includes a chassis configured to support an engine of the machine; a front torsion axle assembly having a first degree of functional stiffness and including: a front axle, a front shaft that extends through a front end of the chassis, and a front arm connecting an end of the front axle to an end of the front shaft; a rear torsion axle assembly having a second degree of functional stiffness that is less than the first degree of functional stiffness, the rear torsion axle assembly including: a rear axle, a rear shaft that extends through a rear end of the chassis, and a rear arm connecting an end of the rear axle to an end of the rear shaft; and an undercarriage configured to move the machine, the undercarriage having: a front sleeve bearing that rotatably receives the front axle, and a rear sleeve bearing that rotatably receives the rear axle, wherein the rear sleeve bearing is substantially identical to the front sleeve bearing.
In some implementations, a suspension and drive system for a machine includes an frame having a front end and a rear end opposite the front end; a front idler rotatably connected to the front end; a rear idler rotatably connected to the rear end; a sprocket rotatably connected to the frame between the front end and the rear end, wherein a first plane extends between an axis of the sprocket and an axis of the front idler, and a second plane extends between the axis of the sprocket and an axis of the rear idler; a front torsion axle rotatably connected to the frame between the sprocket and the front idler; and a rear torsion axle rotatably connected to the frame between the sprocket and the rear idler and between the first plane and the second plane.
This disclosure relates to a suspension and drive system, which is applicable to any machine having wheels and/or tracks. While a compact track loader is illustrated in
To simplify the explanation below, the same reference numbers may be used to denote like features. The drawings may not be to scale.
The suspension and drive system 104, aspects of which will be described below, includes the undercarriage 114, a front torsion axle assembly 116, and a rear torsion axle assembly 118. The undercarriage 114 includes a frame 120, a sprocket 122, a front idler 124, a rear idler 126, a plurality of rollers 128, and a track 130 extending therearound. Although only one undercarriage 114 is depicted in
The sprocket 122, which is rotatably mounted to the upper end 136 of the frame 120, is operatively connected to the engine 106 and is configured to drive the track 130 around the frame 120. The front idler 124 and the rear idler 126 are respectively mounted to the front end 132 and the rear end 134 of the frame 120 and are configured to guide the track 130 therearound. In order to reduce weight of the machine 100 and allow the machine 100 to perform more nimble maneuvers, the rear idler 126 has a diameter that is smaller than a diameter of the front idler 124. The plurality of rollers 128 are rotatably mounted to the lower end 138 of the frame 120 and are configured to guide the track 130 therealong between the front idler 124 and the rear idler 126. The track 130 is a ground-engaging device that encircles the frame 120 and propels the machine 100.
The front torsion axle assembly 116 and the rear torsion axle assembly 118 connect the undercarriage 114 to the chassis 112 via a front sleeve bearing 140 and a rear sleeve bearing 142, respectively. The front sleeve bearing 140 is substantially identical to the rear sleeve bearing 142. As will be described below, the front torsion axle assembly 116 and the rear torsion axle assembly 118 are structured and arranged to constrain movement of the undercarriage 114 relative to the chassis 112 while also reducing shock impact of a ground surface on the machine body 102.
As indicated above,
As indicated above,
As indicated above,
Thus, as the rear arm 316 rotates relative to the chassis 112 during operation of the machine 100, corners 508 of the inner bar 402 move toward the plurality of elastomeric cords 502, causing the inner bar 402 to press into the plurality of elastomeric cords 502. Similar in functionality to a torsion spring, the rear torsion axle assembly 116 has a tendency to return to its original shape (as shown in
As indicated above,
In order to provide a first degree of functional stiffness at a front end of the machine 100 that is greater than a second degree of functional stiffness at a rear end of the machine 100, to thereby provide a balance of both comfort and controllability for the operator, a front interior angle 628 of the quadrilateral 602 at the second vertex 616 is greater than a rear interior angle 630 of the quadrilateral 602 at the fourth vertex 624. The front interior angle 628 and the rear interior angle 630 are acute angles that generally oppose one another. For example, the front interior angle 628 may be in a range of approximately 43 degrees to approximately 57 degrees. The rear interior angle 630 may be in a range of approximately 33 degrees to approximately 45 degrees. A difference between the front interior angle 628 and the rear interior angle 630 may be in a range of approximately 10 degrees to approximately 12 degrees. Because the front leg 604 and the rear leg 606 of the quadrilateral 602 are defined in part by the front arm 306 and the rear arm 316, respectively, the front leg 604 and the rear leg 606 may have approximately equal lengths. For example, the lengths of the front leg 604 and the rear leg 606 may be in a range of approximately 90 millimeters to approximately 210 millimeters. As a further example, the lengths of the front leg 604 and the rear leg 606 of the quadrilateral 602 may be in a range of approximately 90 millimeters to approximately 110 millimeters.
For explanation purposes, the following description will refer to a number of planes as points of reference. In particular, a first plane 632 extends between an axis 634 of the sprocket 122 and an axis 636 of the front idler 124. A second plane 638 extends through axes 640 of the rollers 128. A third plane 642 extends between an axis 644 of the rear idler 126 and the axis 634 of the sprocket 122.
In order to fit both the front axle 302 and the rear axle 312 within the frame 120 without substantially altering the structure of the front axle 302, the rear axle 312, the front sleeve bearing 140, or the rear sleeve bearing 142, a distance between the front axle 302 and the second plane 638 is greater than a distance between the rear axle 312 and the second plane 638. In other words, the torsion axle arrangement 300 includes a vertical offset between the second vertex 616 and the third vertex 620 of the quadrilateral 602. In some instances, the vertical offset may be substantially equal to the length of the front leg 604 (and the rear leg 606) of the quadrilateral 602. Furthermore, the front axle 302 is connected to the frame 120 between the sprocket 122 and the front idler 124 at a position exterior to the first plane 632. In other words, the first plane 632 extends between the axis 626 of the rear axle 312 and the axis 614 of the front axle 302. The rear axle 312 is connected to the frame 120 between the sprocket 122 and the rear idler 126 at a location interior to the second plane 638. In other words, the rear axle 312 extends between the first plane 632 and the second plane 638.
As indicated above,
It should be understood that the first degree of functional stiffness and the second degree of functional stiffness, as described above, differ from one another based on the different angular positions of the front arm 306 and the rear arm 316. In other words, because the front interior angle 628 is greater than the rear interior angle 630, the front arm 306 has a shorter moment arm length than the moment arm length of the rear arm 316. As a result, the front torsion axle assembly 116 is functionally stiffer than the rear torsion axle assembly 118. It should further be understood that the first degree of functional stiffness and the second degree of functional stiffness differ from one another by an amount that is greater than mere engineering tolerance, which constitutes a threshold difference. Thus, the difference between the first degree of functional stiffness, as provided by the front torsion axle assembly 116, and the second degree of functional stiffness, as provided by the rear torsion axle assembly 118, is greater than the threshold difference.
The suspension and drive system 104 of the present disclosure is particularly applicable in a mobile machine, such as the machine 100. For example, the mobile machine may be a loader (e.g., a compact track loader, a skid steer loader, and/or a multi-terrain loader), an excavator, a bulldozer, a cold planer, a trailer, or another type of mobile machine.
Because the torsion axle arrangement 300 has the above-described geometry, the suspension and drive system 104 has a number of benefits over the prior art. For example, because the front interior angle 628 of the quadrilateral 602 is greater than the rear interior angle 630 of the quadrilateral 602, the torsion axle arrangement 300 reduces deflection of the front end of the machine 100 while maintaining a softer feel of the rear end. As a result, the suspension and drive system 104 provides a balance of both comfort and controllability for the operator. As a further example, due to the front sleeve bearing 140 being substantially identical to the rear sleeve bearing 142, the undercarriage 114 has improved ability to support the weight of the machine body 102 and therefore greater stability. Additionally, because the rear idler 126 is smaller than the front idler 124, the machine 100 has a reduced weight, which MAY render the machine 100 more easily maneuverable.
The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the implementations to the precise forms disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the implementations. Furthermore, any of the implementations described herein may be combined unless the foregoing disclosure expressly provides a reason that one or more implementations cannot be combined. Even though particular combinations of features are recited in the claims and/or disclosed in the specification, these combinations are not intended to limit the disclosure of various implementations. Although each dependent claim listed below may directly depend on only one claim, the disclosure of various implementations includes each dependent claim in combination with every other claim in the claim set.
As used herein, “a,” “an,” and a “set” are intended to include one or more items, and may be used interchangeably with “one or more.” Further, as used herein, the article “the” is intended to include one or more items referenced in connection with the article “the” and may be used interchangeably with “the one or more.” Further, as used herein, the terms “comprises,” “comprising,” “having,” “including,” or other variations thereof, are intended to cover non-exclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements, but may include other elements not expressly listed. In addition, in this disclosure, relative terms, such as, for example, “about,” “generally,” “substantially,” and “approximately” are used to indicate a possible variation of ±10% of the stated value, except where otherwise apparent to one of ordinary skill in the art from the context. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise. Also, as used herein, the term “or” is intended to be inclusive when used in a series and may be used interchangeably with “and/or,” unless explicitly stated otherwise (e.g., if used in combination with “either” or “only one of”). Further, spatially relative terms, such as “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the apparatus, device, and/or element in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.
