This application relates to hydrostatic transaxles generally, and in particular to hydrostatic transaxles having a center section assembly that includes a charge pump.
A hydrostatic transaxle for use as a drive apparatus of a vehicle is disclosed herein. The hydrostatic transaxle includes a main housing joined to a gear housing to enclose a hydrostatic transmission and a reduction gear set. The hydrostatic transmission includes an axial piston pump assembly and an axial piston motor assembly arranged in a parallel configuration on one side of a center section. A gerotor charge pump is contained within a pocket on an opposing side of the center section. A charge pump cover assembly secures the gerotor charge pump in the pocket and has a charge relief assembly that extends into a void volume defined by a ring gear of the gear reduction set. The gear reduction set drives an axle extending from the gear housing.
A better understanding of the objects, advantages, features, properties and relationships of the invention will be obtained from the following detailed description and accompanying drawings which set forth illustrative embodiments that are indicative of the various ways in which the principles of the invention may be employed.
The description that follows describes, illustrates and exemplifies one or more embodiments of the invention in accordance with its principles. This description is not provided to limit the invention to the embodiment(s) described herein, but rather to explain and teach the principles of the invention in order to enable one of ordinary skill in the art to understand these principles and, with that understanding, be able to apply them to practice not only the embodiment(s) described herein, but also any other embodiment that may come to mind in accordance with these principles. The scope of the invention is intended to cover all such embodiments that may fall within the scope of the appended claims, either literally or under the doctrine of equivalents.
It should be noted that in the description and drawings, like or substantially similar elements may be labeled with the same reference numerals. However, sometimes these elements may be labeled with differing numbers or serial numbers in cases where such labeling facilitates a more clear description. Additionally, the drawings set forth herein are not necessarily drawn to scale, and in some instances proportions may have been exaggerated to more clearly depict certain features. In certain cross-sectional views, not all elements such as shafts are cross-hatched, where such cross-hatching would not assist in the understanding of the disclosure. This specification is intended to be taken as a whole and interpreted in accordance with the principles of the invention as taught herein and understood by one of ordinary skill in the art. All commonly-owned patents cited within this specification are expressly incorporated by reference herein.
One application for transaxle 110 is in combination with a modular drive assembly such as that disclosed in commonly owned U.S. Pat. No. 8,393,236 and U.S. Pat. No. 9,194,473, the terms of which are incorporated herein by reference.
Center section assembly 171, best seen in
At least a portion of charge relief assembly 175 is disposed in the internal void volume formed by ring gear 170 as shown in, e.g.,
As seen most clearly in
For adjusting the output of hydrostatic transaxle 110, swash plate 154 is in contact with pump thrust bearing 156 against which pump pistons 133 travel as shown in
Generally, as the angle of swash plate 154 is varied in one direction from the neutral position, the stroke of the pump pistons 133 is varied, which then drives the motor assembly 136 at a speed determined by the volume of the fluid displaced by the pump pistons 133. As the angle of the swash plate 154 is decreased to pass through the neutral position, the direction of rotation of motor assembly 136 and its corresponding motor output shaft 146 is reversed. The speed of the motor is again determined by the volume of fluid displaced by the pump pistons 133.
Axle shaft 162 is rotationally supported by inner axle bearings 164, set in bearing pocket 140k of center section 140, and outer axle bearings 166. Outer axle bearings 166 are supported by bearing support structure 124a of gear housing 124. To drive axle shaft 162, reduction gearing is provided to couple axle shaft 162 to motor shaft 146, imparting thereto an appropriate speed and torque. Thus, the proximal end of motor shaft 146 is splined to pinion gear 168 which drives ring gear 170. Ring gear 170 in turn drives sun gear 172 which drives planet gears 174. Because the planetary ring gear 178 is held stationary, the planet gears 174 drive planet gear carrier 176 which is splined to axle shaft 162. Other known reduction schemes may be employed to impart an appropriate speed and torque to axle shaft 162. An optional brake rotor 197 can be fixed to motor shaft 146 to provide braking capability if additional brake components (not shown) are also included. As shown most clearly in
While specific embodiments have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those presented herein could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the appended claims and any equivalent thereof.
This application is a continuation of U.S. patent application Ser. No. 14/204,865, filed Mar. 11, 2014, which claims priority to U.S. Provisional Patent Application No. 61/776,522, filed on Mar. 11, 2013. These applications are incorporated herein by reference in their entirety.
Number | Name | Date | Kind |
---|---|---|---|
1197789 | Bluemel | Sep 1916 | A |
3199376 | De Lalio | Aug 1965 | A |
3360933 | Swanson | Jan 1968 | A |
3765258 | Jespersen | Oct 1973 | A |
4366671 | Chichester | Jan 1983 | A |
5311740 | Shiba et al. | May 1994 | A |
5555727 | Hauser et al. | Sep 1996 | A |
5819535 | Smothers | Oct 1998 | A |
6125954 | Oota et al. | Oct 2000 | A |
6312354 | Irikura et al. | Nov 2001 | B1 |
6487857 | Poplawski et al. | Dec 2002 | B1 |
6530855 | Folsom et al. | Mar 2003 | B1 |
6971233 | Holder | Dec 2005 | B1 |
7007468 | Bennett et al. | Mar 2006 | B1 |
7987669 | Irikura | Aug 2011 | B2 |
8348637 | Heitzler et al. | Jan 2013 | B2 |
8393236 | Hauser et al. | Mar 2013 | B1 |
8464610 | Langenfeld et al. | Jun 2013 | B1 |
8528325 | Hauser | Sep 2013 | B1 |
9194473 | Hauser | Nov 2015 | B1 |
9388892 | Bonny | Jul 2016 | B1 |
Number | Date | Country |
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2001318611 | Nov 2001 | JP |
Number | Date | Country | |
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61776522 | Mar 2013 | US |
Number | Date | Country | |
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Parent | 14204865 | Mar 2014 | US |
Child | 15205312 | US |