Drive assembly

Saturday, 20 July 2013

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Drive assembly

Abstract
An improved drive assembly includes a gerotor type hydraulic motor having a housing connected to a frame. An output member rotatably mounted on a hollow shaft which is formed integrally with the motor housing. Operation of the motor rotates an input shaft which is disposed within the spindle and is connected to the output member through a gear arrangement. In order to tend to minimize the axial extension of the drive assembly, the gear arrangement is located inward from an outer end of the spindle. The gear arrangement includes a central or sun gear is disposed within the spindle. A plurality of intermediate gears extending through openings formed in the spindle in engagement with the central gear. These idler gears meshing involve a ring gear which is fixedly connected to the output member. The gerotor hydraulic motor includes a swing axis, which is connected to the input shaft to the sun gear by a coupling element. A stop member is movable in the spindle to disengage the input shaft to turn sun gear drive assembly. 
DescriptionBackground of the InventionThe present invention relates to a drive assembly to rotate an output member.There are many known hydraulic drive units are used for many different purposes, including driving lathes, mixers, and the wheels of the vehicle. One of these known hydraulic drive assemblies described in U.S. Pat. No. 3686978. This known hydraulic drive assembly includes a hydraulic motor which is bolted to a spindle

axis. A vehicle wheel is rotatably mounted on the axle spindle by a pair of bearing assemblies. A reduction gear unit of the planetary type is mounted to the outside of the axle spindle and is effective to reduce the rate at which the wheel is driven on the operation of the drive motor.To enable a vehicle to be used under certain operating conditions, it is desirable to minimize the axial extension of the drive assembly of the wheel. Of course, when a gear reduction unit is mounted to the outside of the axle spindle, the drive assembly of the wheel tends to have a relatively large axial extension. The axial drive assembly also known wheel tends to increase for the provision of a motor housing which is separate from the axle spindle.SUMMARY OF THE PRESENT INVENTIONThe present invention relates to a relatively compact and easy to drive mount that can be used for many different purposes, including driving a mixer or driving winch. In the specific preferred embodiment described herein, the drive assembly is used to rotate the wheel of a vehicle. This drive assembly includes a hydraulic motor having a housing which is formed integrally with a spindle axis. A hub which is adapted to be connected to a vehicle wheel is rotatably mounted on the axle spindle. To tend to minimize the axial extension of the actuator assembly, a set of gears for the transmission of drive forces from the engine to the wheel axis and is disposed inwardly of an outer end of the axle spindle. To facilitate the towing, the motor can be disconnected from the gear arrangement. It should be understood that the improved drive assembly may be used to transmit drive forces in other environments that vehicle units.Accordingly, it is an object of this invention to provide a drive assembly to rotate an output member and in which the drive assembly has a relatively compact construction and short axial extension.Another object of this invention is to provide a set of new and improved actuator for rotating an output member, such as a vehicle wheel, and wherein the drive assembly includes a motor having a housing that is integrally formed a shaft rotatably supporting the output member.Another object of this invention to provide a drive assembly including a gear arrangement which is disposed inwardly of an outer end of a spindle and operable to rotate an output member in the operation of a drive motor.BRIEF DESCRIPTION OF THE DRAWINGSThe foregoing and other objects and features of the present invention will become more apparent upon a consideration of the following description taken in connection with the accompanying drawings in which:. Figure 1 is a sectional view of a drive assembly constructed in accordance with the present invention;. Figure 2 is a view taken along line 2 - 2 of FIG. 1 and illustrating the manner in which the drive assembly is connected to a vehicle frame;. Figure 3 is an enlarged sectional view of a portion of the drive assembly of FIG. 1;. Figure 4 is a sectional view taken generally along line 4 - 4 in Fig. 1 illustrating the relationship between a spindle shaft, gear arrangement and the wheel hub;. Figure 5 is an enlarged sectional view taken generally along the line 5 - 5 in FIG. 1 illustrating the relationship between a rotor and stator of a hydraulic drive motor;. Figure 6 is an enlarged fragmentary sectional view of a portion of the drive assembly of FIG. 1 illustrating an input shaft of the gear arrangement into a disengaged condition, and. 7 is an enlarged fragmentary view of a second embodiment of the invention which uses the fluid pressure forces to move an input shaft to an engaged condition.SPECIFIC DESCRIPTION OF A PREFERRED EMBODIMENT OF THE INVENTIONA compact drive assembly 10 (Figure 1) is advantageously used to rotate a wheel or output element 12 with respect to a base or frame 14 of a vehicle. However, the drive assembly 10 could be used in other environments, if desired. The drive assembly 10 includes a gerotor type hydraulic motor 16 having a housing 18 which is fixedly connected with the base frame 14 by suitable fasteners 20 (Figure 2). Housing 18 (Figure 1) of the motor is integrally formed with a spindle shaft 24 on which a hub 26 is rotatably supported by suitable bearings 28 and 30. A gear arrangement 32 transmits the driving forces of an input shaft 34 to hub 26. The input shaft 34 is connected with a pivot shaft or the drive link 38 of the motor 16 by an internally splined coupling 40.

In order to reduce the axial extent of the mounting unit 10, the gear arrangement 32 is mounted in a middle section 44 of the spindle 24 between the sets of bearings 28 and 30. The gear arrangement 34 includes a central or sun gear 48 (see FIGS. 3 and 4) which is arranged within a chamber 50 which extends axially formed within the axle spindle 24. The chamber 50 has a circular cross-sectional configuration and fully encloses the sun gear 48. Intermediate gears 54, 56, and 58 (Figure 4) extending through apertures 62, 64, and 66 formed in a cylindrical wall 68 of the axle spindle 24. The intermediate gears 54, 56, and 58 are disposed in meshing engagement with both the sun gear 48 and an annular ring gear 72 which is fixedly connected with the hub 26.The intermediate gears 54, 56, and 58 are supported in the middle section 44 of the spindle 24 by a pair of annular collars 76 and 78 (see Fig. 1) and support pins 90 (see Figs. 1 and 4) . The collar 76 is connected to the spindle shaft 24 by the engagement of internal splines 94 with external splines 96 formed in the axle spindle 24. The grooves 94 and 96 have the collar 76 against rotation about the central axis 100 of the axle spindle. The collar 76 is held against movement axially inwardly by a spacer member 104. The two collars 76 and 78 are held against movement axially outward by a retaining ring 106 which engages an annular groove in the axle spindle 24.After rotation of the input member 34 and the sun gear 48 about the central axis 100 of the axle spindle 24, idler gears 54, 56, and 58 are rotated around the support pins 90 to drive the gear ring 72. Since ring gear 72 is fixedly connected with the hub 26 and the wheel 12, the wheel and hub are rotated with the rotation of the sun gear 48. Note that the hub 26 is supported for rotation about the axis 100 by the inner and outer gear assemblies 28 and 30 (Figure 1). Therefore an annular inner end wall 110 is fixedly connected with a generally cylindrical wall 112 and the hub 26 engages the inner bearing assembly 28. An annular outer wall 114 that is integrally formed with wall 112, is coupled to the bearing assembly 30. The wheel 12 is fixedly connected with the outer wall 114 of hub 26 through appropriate connections 118.In order to stop rotation of the wheel 12, a disc brake assembly 120 (Figure 1) is associated with the wheel hub 26. The disk brake assembly 120 includes a caliper assembly 124 (shown schematically in. Figure 1) which is operable to hold an annular disc 126 in a known manner. The disc 126 is fixedly connected to the hub 26. The caliper assembly 124 is fixedly connected to the vehicle frame 14 so that the operation of the caliper assembly, the disc 126 and the hub 26 are held against rotation relative to the vehicle frame for stopping the wheel thereby 12.The hydraulic drive motor 16 is gerotor type and includes a stator toothing 130 (Figure 5) which is fixedly connected with the motor housing 16. An externally toothed rotor 132 and is rotated in orbit relative to the stator 130 under the influence of high pressure fluid carried in some of the pockets formed between the rotor 132 and stator 130. Other pockets formed between the stator 132 and the rotor 130 is exhausted to drain so that the high pressure fluid is effective to rotate and the rotor orbit. A valve assembly cooperating with a rotor 132 for sequentially connecting the pockets formed between the rotor and the stator 130 with a high pressure source of fluid and the drain as described in U.S. Pat. No. 3606601. Although one specific stator and rotor construction shown in Fig. 5, it is contemplated that other known stator and rotor structures could be used if desired. For example, one could use a hydraulic motor having a stator vane.An inner end portion 140 of the oscillation shaft 38 is connected to the rotor 132. Therefore, as the rotor 132 rotates and orbits relative to the stator 130, the inner end of the oscillation shaft 140 is also rotated and orbit. Since the rotor 132 has six teeth, which is one less than the number of teeth in the stator 130, the inner end of the oscillation shaft 38 is rotated through one complete revolution each time it is complete six orbits. A grooved outer end portion 144 of the swing shaft 38 (see FIGS. 1 and 2) is disposed in meshing engagement with internal splines 146 of the coupling 40. The coupling 40 is mounted for rotation about a central axis 100 of the axle spindle 24 by a thrust bearing assembly 148 and a radial bearing 149. In view of the fact that the coupling member 40 is rotated through one revolution around the central axis 100 each time the oscillation shaft 38 is rotated through one revolution, there is a six-to-one between reducing the rotational speed of the rotor 132 and the rotation speed of the coupling member 40. Since the operation mode of the hydraulic motor 16 and the manner in which the swing axis 38 cooperates with the rotor 132, stator 130, and the coupling member 40 is, in itself, well known, will not be further in this document to avoid prolixity of description.The rotational movement of the coupling 40 is transferred to the input shaft 152 internal splines 34 formed in the coupling member. These internal splines 152 are arranged in meshing engagement with external splines 154 on the input member 34 (see fig. 3). Therefore, the input member 34 is rotated through one complete revolution each time the coupling member 40 is rotated through a complete revolution.The gear arrangement 32 effects a reduction of four to a gear. Therefore, whenever the input shaft 34 is rotated through four revolutions, the hub member 26 is rotated through a complete revolution. A twenty-to-one reduction gear is disposed between the rotor 132 (see fig. 5) and the hub 26. This relatively large gear reduction results from the fact that there is a six-to-one gear reduction between the rotor 132 and the input shaft 34 and a four to one reduction gear between the input shaft 34 and the hub 26. Of course, the rotor 132, stator 130, and the gear arrangement 32 may be sized to obtain different gear reduction. The specific values ​​for reduction gears are set forth herein only for purposes of clarity of description.It is contemplated that under certain conditions, be desirable to disconnect the motor 16 of the wheel 12 so that the wheel can rotate freely, for example when the vehicle is to be towed. To disconnect the motor 16 of the wheel 12, the input shaft 34 moves axially away from the engaged position shown in FIG. 3 to the disengaged position shown in Fig. June. This outward movement of input shaft 34 is disengaged from the splines 152 on the coupling member 40 of the grooves 154 on the input member 34.To release the input shaft 34 to axially outward movement, circular stop member 160 moves axially outward with respect to the spindle 24. This is accomplished by releasing retaining ring 164, an annular groove 166 formed in axle 24 (Figure 3). The retaining ring 164 is positioned to engage a second groove 168 to hold the stop member 160 at a position shown in Fig. June. When the stop member 160 is in this position, a spring 172 pushing the input shaft moves outwardly against the stop member 160. As this occurs, the internal splines in the coupling element 40 is disengaged from the external splines on the input member 154. Therefore, rotation of the coupling member 40 by the oscillation shaft 38 is ineffective to rotate the input member 34. Furthermore, if the vehicle is towed, the rotation of the wheel 12 and the hub 26 is ineffective to drive coupling member 40 and the pivot axis 38 so that the wheel 12 can freely rotate relative to the spindle axis 24.

In the embodiment of the invention illustrated in FIGS. 1 to 6, the motor 16 is disconnected from the wheel 12 by moving the stop member 160 axially outwardly. It is contemplated that when the drive assembly 10 is used in certain environments, for example in combination with lathes, drives four wheels, or a unit of a single wheel may be advantageous to allow the motor 16 to be disconnected rapidly from the gear arrangement 32 without disengaging the snap ring 164 for releasing the stop member 160. Accordingly, in the embodiment of the invention illustrated in FIG. 7, an input member is axially displaced under the influence of a force of fluid pressure for operating the drive assembly in a disengaged condition to an engaged condition in which the input member is effective to transmit drive forces from an engine hydraulic gear arrangement. Since the embodiment of the invention illustrated in FIG. 7 is generally similar to the embodiment of the invention illustrated in FIGS. 1-6, like numerals are used to designate similar components, the suffix letter to be added to the numbers associated with FIG. 7 to avoid confusion.In the embodiment of the invention illustrated in FIG. 7, a pressure chamber 180 is formed in the axially outer end portion of the axle spindle 24. The pressure chamber 180 is connected by a conduit 182 to a suitable control valve (not shown). When the wheel hub (not shown) will be activated, the pressure fluid is conducted from the control valve through the conduit 182 to the chamber 180. This applies fluid pressure against a piston 186 to move an input shaft 34a axially to the left (as viewed in Fig. 7). This leftward movement of the input shaft 34a moves axially extending external splines 154a on the input shaft 34a in meshing engagement with the internal teeth or grooves 152a formed in a coupling member 40a. The coupling member 40a is then connected to a drive gear arrangement 32a in much the same way as illustrated in Fig. 3 for the embodiment of the invention shown in FIGS. 1-6.When the hydraulic drive between the engine and the coupling 40a to disconnect the chamber 180 is exhausted to drain through the conduit 182. This allows input shaft 34a to be moved axially outwardly to the disengaged position shown in Fig. 7 under the influence of a biasing spring 172a. When the input shaft 34a is in the disengaged position of FIG. 7, the operation of the associated hydraulic drive motor is ineffective to operate the gear arrangement 32a.In view of the above description, it can be seen that the drive assembly 10 is relatively compact and is capable of being used in many different environments to carry out a relatively large gear reduction. The compact size of the drive assembly 10 results from the combined effects of integrally forming the housing 18 and the spindle 24, the assembly of the gear arrangement portions 32 between the inner and outer end of the spindle, and the participation of the coupling member 40 with the outer end of the swing shaft 38. After operation of the hydraulic motor 16 under the influence of high pressure hydraulic fluid, the rotor 132 rotates relative to the stator 130 for rotating the swing shaft 38. This rotation of the oscillation shaft 38 rotates the splined input shaft 34 which is connected to the sun gear 48. The sun gear 48 is disposed within the spindle shaft 24 between the two bearing assemblies 28 and 30. After rotation of the sun gear 48, idler gears 54, 56, and 58 extending through openings in the wall of the axle spindle 24 in meshing engagement with the sun gear 48 are rotated to rotate the gear ring 72 which is fixedly connected with the hub 26.Although the drive assembly 10 has been described herein in association with a vehicle wheel, it is contemplated that the drive assembly can be used in many different environments. For example, the drive assembly could be used to rotate the drum of a winch instead of a vehicle wheel. In such an environment, the hydraulic motor 16 is connected with the base frame or with the spindle of the winch 24 in a coaxial relationship with the winch drum. The gear arrangement 32 would then transmit drive forces from the input shaft 34 to the hub 36 connected to the winch drum. Although the screw 24 is described as being in a coaxial relationship with the wheel 12 and may be advantageously mounted in a coaxial relationship with a drum of the winch, it is contemplated that the hub 26 may be provided with external gear teeth and is limited to being a gear in a gear train connected to a drive element, such as the winch drum or vehicle wheel.