Patent Publication Number: US-2017363192-A1

Title: Hydraulic device with sleeve insert

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is being filed on Nov. 16, 2015 as a PCT International Patent Application and claims the benefit of U.S. Patent Application Ser. No. 62/080,790, filed on Nov. 17, 2014, the disclosure of which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     Hydraulic devices that are used in a variety of applications, such as propel-vehicle applications, can include hydraulic motors and brake packages. In certain examples, brake packages can be used as integral brake packages with low-speed, high-torque gerotor motors. Such hydraulic devices include a stationary housing and a rotating housing configured to rotate relative to the stationary housing when driven by an associated hydraulic motor. In some configurations, the stationary housing and the rotating housing cooperate to define an interior brake fluid chamber to actuate an associated brake mechanism. 
     SUMMARY 
     The present disclosure is directed to a hydraulic device with a sleeve insert disposed between a driven hub and a stationary housing. 
     In one aspect, the hydraulic device may include a stationary housing and a driven hub configured to rotate relative to the stationary housing. The hydraulic device may include a hydraulic motor to actuate the driven hub through a drive shaft. The stationary housing and the driven hub defines a brake fluid chamber to actuate a brake mechanism for the driven hub. The brake fluid chamber may be sealed by a sealing element disposed at an interface between the stationary housing and the driven hub. As the driven hub rotates relative to the stationary housing, the interface between the driven hub and the stationary housing can be subjected to wear, resulting in replacement of at least one of the driven hub and the stationary housing. Further, for appropriate sealing, the driven hub and the stationary housing do not allow a large clearance at the interface thereof Such a small clearance can make it difficult to assemble the driven hub with the stationary housing without damage to the interface between the driven hub and the stationary housing. 
     To minimize the wear of the driven hub and/or the stationary housing, the hydraulic device includes a sleeve insert disposed at the interface between the driven hub and the stationary housing. A sealing element may be disposed between the sleeve insert and the stationary housing. The sleeve insert is disposed between the stationary housing and the driven hub to provide a riding surface on which the sealing element slides as the driven hub rotates relative to the stationary housing. Because the sleeve insert is made as a separate piece from the driven hub, the driven hub can be made of a less wear-resistant material, thereby reducing manufacturing costs of the hydraulic device. 
     Further, the configuration of the driven hub with the separate sleeve insert can ease assembly of the driven hub to the stationary housing. This can allow for an increased clearance between the stationary housing and the driven hub during the installation. In certain examples, the driven hub is first installed over the stationary housing without the sleeve insert. Then, the sleeve insert is disposed between the driven hub and the stationary housing to provide a riding surface for the sealing element arranged between the driven hub and the stationary housing as the driven hub rotates relative to the stationary housing. This configuration can thereby reduce assembly costs and minimize a risk of damage to a seal surface for the sealing element during the installation. 
     The above features and advantages and other features and advantages of the present teachings are readily apparent from the following detailed description of the best modes for carrying out the present teachings when taken in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are incorporated in and constitute a part of the description, illustrate several aspects of the present disclosure. A brief description of the drawings is as follows: 
         FIG. 1  is an isometric view of an example hydraulic device having exemplary features in accordance with the principles of the present disclosure. 
         FIG. 2  is an exploded isometric view of exemplary components of the hydraulic device of  FIG. 1 . 
         FIG. 3  is an exploded isometric view of exemplary components of  FIG. 2  including a brake assembly and a sleeve insert suitable for use in the hydraulic device of  FIG. 1 . 
         FIG. 4  is a cross-sectional view of the hydraulic device of  FIG. 1 . 
         FIG. 5  is an isometric cross-sectional view of the hydraulic device of  FIG. 1  illustrating the sleeve insert and associated components of the hydraulic device. 
         FIG. 6  is an isometric view of an exemplary sleeve insert. 
         FIG. 7  is a flowchart illustrating an example of assembling the hydraulic device of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to the exemplary aspects of the present disclosure that are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like structure. 
     Examples of the disclosure described above may be particularly useful in propel vehicle applications, such as compact track loaders, sprayers, combines or other low speed, high torque vehicles. One or more hydraulic devices may be coupled to a track, a wheel or a sprocket/gear driving a track. Hydraulic devices in accordance with the principles of the present disclosure can also be used to drive chipping/grinding drums, chipping/grinding wheels or discs, drill heads, or other rotatable structures. 
     Generally disclosed is a hydraulic device. The hydraulic device may include a stationary housing and a driven hub configured to rotate relative to the stationary housing. A hydraulic motor is provided to actuate the driven hub through a drive shaft and a coupling mechanism. The hydraulic device includes a sleeve insert disposed between the driven hub and the stationary housing. A sealing element is disposed between the sleeve insert and the stationary housing. The sleeve insert is fixed to the driven hub and disposed between the stationary housing and the driven hub to provide a riding surface on which the sealing element slides as the driven hub rotates relative to the stationary housing. The sleeve insert, as a separate piece from the driven hub, can allow the driven hub to be made of a less wear-resistant material, thereby reducing manufacturing costs of the hydraulic device. Further, the configuration of the driven hub with the separate sleeve insert can ease assembly of the driven hub to the stationary housing. This configuration can allow for an increased clearance between the stationary housing and the driven hub during the installation, thereby reducing assembly costs and minimizing a risk of damage to a seal surface for the sealing element during the installation. 
     Referring to  FIGS. 1-9 , a hydraulic device  100  is disclosed in accordance with the principles of the present disclosure. In some examples, the hydraulic device  100  is configured as a combined hydraulic motor and brake assembly. In this document, therefore, the hydraulic device  100  can also be referred to as the combined hydraulic motor and brake assembly. The hydraulic device  100  may include a stationary housing  102 , a driven hub  104 , a coupling mechanism  106 , and a hydraulic motor  108 . 
     The stationary housing  102  is configured to couple the hydraulic device  100  to a non-driven and stationary element such as a portion of a vehicle frame. The stationary housing  102  can also be referred to as an inner housing. The stationary housing  102  includes a main body  110  and a mounting flange  112  projecting radially outwardly from the main body  110 . The mounting flange  112  defines a plurality of first fastener openings  114  for receiving first fasteners (e.g., bolts not shown) used to secure the stationary housing  102  to the non-driven and stationary element. The mounting flange  112  is generally semi-circular in shape, but other shapes could be used as well (e.g., full rings or other shapes). In other examples, the hydraulic device  100  may include other mounting assemblies for coupling the hydraulic device  100  to a non-driven and stationary element. 
     The driven hub  104  is configured to couple the hydraulic device  100  to a driven and non-stationary element such as a wheel, sprocket or other structure intended to be rotated. The driven hub  104  can also be referred to as an outer housing or a rotating housing. The driven hub  104  may be mounted at least partially over the stationary housing  102 . The driven hub  104  includes a main body  116  and a plurality of tabs  118  that project radially outwardly from the main body  116 . The tabs  118  are circumferentially spaced around a perimeter of the main body  116  of the driven hub  104 . The driven hub  104  includes a plurality of second fastener openings  120  for receiving second fasteners (e.g., bolts not shown) used to secure the driven hub  104  to a driven element. The second fastener openings  120  may be defined through the tabs  118 . The tabs  118  are separated by pockets  122 . At least some of the pockets  122  may align with the first fastener openings  114  to facilitate accessing the first fastener openings  114 , for example during the installation of the hydraulic device  100 . In other examples, configurations other than tabs (e.g., solid flanges or other structures) can be used to connect the driven hub to a driven element. In yet other examples, the hydraulic device  100  may include other mounting assembles for coupling the hydraulic device  100  to a driven and non-stationary element. 
     The coupling mechanism  106  operates to couple the drive shaft  130  to the driven hub  104  such that torque from the drive shaft  130  is transferred to the driven hub  104  causing the driven hub  104  to rotate relative to the stationary housing  102 . An example of the coupling mechanism  106  is illustrated and described herein in more detail. 
     The hydraulic motor  108  operates to rotate the drive shaft  130  relative to the stationary housing  102 . An example of the hydraulic motor  108  is illustrated and described herein in more detail. 
     Referring to  FIG. 4 , a cross-sectional view of the hydraulic device  100  is illustrated. As described above, the hydraulic device  100  includes the stationary housing  102 , the driven hub  104 , the coupling mechanism  106 , and the hydraulic motor  108 . In addition, the hydraulic device  100  includes a main drive shaft  130 , a sleeve insert  170 , and bearings  180  and  182 . 
     As described above, the stationary housing  102  includes the main body  110 . The main body  110  has a first housing end  132  and a second housing end  134  opposite to the first housing end  132  along an axis of rotation A. The main body  110  may include a base portion  136  and a shaft portion  138 . The base portion  136  is arranged at the first housing end  132 . The shaft portion  138  projects from the base portion  136  and extends between the first and second housing ends  132  and  134 . The shaft portion  138  defines a shaft passage  140  through which the main drive shaft  130  extends. 
     The stationary housing  102  may include a sealing groove  142  radially formed around the outer circumference of the shaft portion  138 . As described herein, the sealing groove  142  is adapted to receive a sealing element  144  such that the sealing element  144  (e.g., an annular gasket such as an elastomeric O-ring) is disposed between the stationary housing  102  and the driven hub  104 . 
     The driven hub  104  includes a first hub end  146  and a second hub end  148  opposite to the first hub end  146  along the axis of rotation A. The driven hub  104  defines an inner bore  150  ( FIG. 3 ) that generally extends between the first and second hub ends  146  and  148 . 
     The driven hub  104  includes an inner wall  152  radially inwardly extending from an inner surface of the driven hub  104 . The inner wall  152  has a first axial face  154  and a second axial face  156  opposite to the first axial face  154 . The first axial face  154  is arranged toward the first hub end  146 , and the second axial face  156  is arranged toward the second hub end  148 . When the driven hub  104  is assembled with the stationary housing  102 , the first axial face  154  is arranged to face the first housing end  132  and the second axial face  156  is arranged to face the second housing end  134 . In some examples, as shown in  FIGS. 4 and 5 , the first and second axial faces  154  and  156  can at least partially include one or more recessed portions such that a width of the inner wall  152  (i.e., a distance between the first and second axial faces  154  and  156 ) along the axis of rotation A at the recessed portions is smaller than other portions of the inner wall  152 . In the depicted example, the first and second axial faces  154  and  156  have recessed portions, respectively, which are symmetrically positioned relative to a center axis of the inner wall  152  perpendicular to the axis of rotation A. The recessed portions of the first and second axial faces  154  and  156  do not contact the bearings  180  and  182  while the other portions of the faces  154  and  156  contact the bearings  180  and  182 . In other examples, such recessed portions can have different shapes and arrangements. For example, only one of the first and second axial faces  154  and  156  can have a recessed portion. 
     The inner wall  152  further has a radial end  158  connecting the first and second axial faces  154  and  156 . The radial end  158  of the inner wall  152  defines an opening through which the shaft portion  138  of the stationary housing  102  passes, and thus generally faces the outer surface of the shaft portion  138  of the stationary housing  102  when the driven hub  104  is assembled with the stationary housing  102 . 
     The inner wall  152  of the driven hub  104  is configured to mount the sleeve insert  170  thereon such that the sleeve insert  170  is disposed between the radial end  158  of the inner wall  152  and the sealing groove  142  of the stationary housing  102 . As described herein, the sleeve insert  170  provides a riding surface  176  ( FIG. 6 ) on which the sealing element  144  disposed in the sealing groove  142  slides as the driven hub  104  rotates relative to the stationary housing  102 . 
     In some examples, the inner wall  152  includes a recess  160  formed on the second axial face  156  at the radial end  158 . The recess  160  reduces a width of the inner wall  152  at or around the radial end  158 . The recess  160  is configured to receive a flange portion  174  ( FIG. 5 ) of the sleeve insert  170  and operate as a positive stop that limits inward axial movement of the sleeve insert  170  relative to the inner wall  152 . For example, when the sleeve insert  170  is fitted to the inner wall  152  at the radial end  158 , the recess  160  limit the insertion of the sleeve insert  170  to the inner wall  152  by engaging the flange portion  174  of the sleeve insert  170  therewith. 
     Referring to  FIGS. 4 and 5 , the sleeve insert  170  is mounted on the radial end  158  of the inner wall  152  to provide a riding surface  176  ( FIG. 6 ) for the sealing element  144  disposed in the sealing groove  142  of the stationary housing  102  (e.g., the shaft portion  138  thereof). As described herein, the sleeve insert  170  is mounted between the inner wall  152  of the driven hub  104  and the outer surface of the shaft portion  138  of the stationary housing  102  after the driven hub  104  is installed over the stationary housing  102  (i.e., after the shaft portion  138  of the stationary housing  102  is inserted into the opening defined by the inner wall  152  of the driven hub  104 ). In some examples, the sleeve insert  170  is interference-fitted (e.g., press-fitted or friction-fitted) to the inner wall  152  of the driven hub  104 . In other examples, the sleeve insert  170  can be fastened to the inner wall  152  of the driven hub  104 . In yet other examples, the sleeve insert  170  can be attached to the driven hub  104  with adhesive. The sealing element  144  can be an annular gasket, such as an elastomeric O-ring seal, X-ring seal, and duo cone seal. 
     Referring to  FIG. 6 , in some examples, the sleeve insert  170  includes a body portion  172  and a flange portion  174 . The body portion  172  is configured as a cylindrical shape defining an opening through which the shaft portion  138  of the stationary housing  102  passes. The body portion  172  has an inner diameter D 1  that is slightly larger than an outer diameter D S  of the shaft portion  138  of the stationary housing  102  such that the driven hub  104  rotates around the shaft portion  138  of the stationary housing  102 . A difference or gap between the inner diameter D 1  of the sleeve insert  170  and the outer diameter D S  of the shaft portion  138  ranges between 1/500 and 1/7000 inches. In some examples, the gap is about 1/1000 inches. In other examples, the gap is about 1/5000 inches. Other gaps can be used as well depending on different applications. 
     The flange portion  174  of the sleeve insert  170  radially outwardly extends from the body portion  172  of the sleeve insert  170 . In some examples, as shown in  FIGS. 4 and 5 , the flange portion  174  projects from the body portion  172  at one axial end of the body portion  172  such that the body portion  172  and the flange portion  174  form an L-shape. In other examples, the flange portion  174  radially extends from the body portion  172  between the opposite axial ends of the body portion  172 . The flange portion  174  is dimensioned to seat against the recess  160  when the sleeve insert  170  is fitted to the inner wall  152  at the radial end  158 . In some examples, the flange portion  174  may be shaped to correspond to the recess  160  of the inner wall  152 . As the sleeve insert  170  is inserted and fitted to the radial end  158  of the inner wall  152 , the flange portion  174  engages the recess  160  of the inner wall  152  so as to limit the insertion of the sleeve insert  170  and arrange the sleeve insert  170  in place with respect to the inner wall  152 . 
     In some examples, a sealing element  178  (e.g., an annular seal having an elastomeric character, such as an O-ring, X-ring, duo cone ring, or other seals) can be provided between the sleeve insert  170  and the inner wall  152  of the driven hub  104 . For example, the sealing element  178  can be arranged at the corner formed by the body portion  172  and the flange portion  174  and disposed between the sleeve insert  170  and the radial end  158  of the inner wall  152  when the sleeve insert  170  is fitted into the inner wall  152 . 
     The body portion  172  of the sleeve insert  170  can provide a seal riding surface  176  defined by an inner radial surface of the body portion  172 . The seal riding surface  176  faces radially inwardly toward the axis of rotation A. The seal riding surface  176  provides a surface on which the sealing element  144  disposed in the sealing groove  142  of the shaft portion  138  of the stationary housing  102  slides as the driven hub  104  rotates relative to the stationary housing  102 . Accordingly, the body portion  172  of the sleeve insert  170  is subjected to wear during operation of the hydraulic device  100 . 
     The sleeve insert  170  can be made of wear-resistant material. For example, the sleeve insert  170  can be made of hardened steel. In some examples, the sleeve insert  170  can be made of a material different from the driven hub  104 . For example, the sleeve insert  170  can allow the use of a less expensive, wear-resistant material in making the driven hub  104 . Typically, the driven hub  104  is made of a single material. Without the sleeve insert  170 , the inner wall  152  (e.g., the radial end  158 ) of the driven hub  104  can directly contact the sealing element  144  and/or the outer surface of the shaft portion  138  of the stationary housing  102 . Thus, the driven hub  104  should be entirely replaced when the inner wall  152  is worn at or above a predetermined level. Alternatively, the entirety of the driven hub  104  should be made with expensive wear-resistant material to increase its product life. By making the sleeve insert  170  as a separate piece from the driven hub  104 , the driven hub  104  can be made of a less wear-resistant material, thereby reducing manufacturing costs. 
     Further, the configuration of the driven hub  104  with the separate sleeve insert  170  can ease assembly of the driven hub  104  to the stationary housing  102 . This configuration can allow for an increased clearance between the shaft portion  138  of the stationary housing  102  and the inner wall  152  of the driven hub  104  during the installation, thereby reducing assembly costs and minimizing a risk of damage to a seal surface for the sealing element  144  during the installation. Further, the sleeve insert  170  is mounted after the stationary housing  102  and the driven hub  104 , which are large and ing mechanism. A sealing element is disposed between the sleeve insert and the stationary the stationary housing  102  and the driven hub  104  by inserting the sleeve insert  170  therebetween. 
     The hydraulic device  100  may include the bearings including a first bearing  180  and a second bearing  182  that are positioned between the stationary housing  102  and the driven hub  104  to allow the driven hub  104  to rotate relative to the stationary housing  102  about the axis of rotation A, which extends through the shaft passage  140 . The axis of rotation A is defined by the bearings  180  and  182 . The bearings  180  and  182  can be of a variety of type. In some examples, the bearings  180  and  182  are thrust bearings. 
     The first bearing  180  may be disposed adjacent the first housing end  132  between the shaft portion  138  and the inner surface of the driven hub  104 . In some examples, the first bearing  180  is arranged to abut the first axial face  154  of the inner wall  152  of the driven hub  104 , as illustrated in  FIGS. 4 and 5 . Similarly to the first bearing  180 , the second bearing  182  may be disposed at the other side of the inner wall  152 , opposite to the first bearing  180 . In some examples, the second bearing  182  is arranged to abut the second axial face  156  of the inner wall  152  of the driven hub  104 , as illustrated in  FIGS. 4 and 5 . The arrangement of the first and second bearings  180  and  182  on the opposite sides of the inner wall  152  can provide a balanced support for the driven hub  104  relative to the stationary housing  102  when the driven hub  104  rotates. 
     Although it is illustrated that two bearings are provided to the hydraulic device  100 , other examples can include only one bearing, or three or more bearings, disposed between the driven hub  104  and the stationary housing  102 . 
     In addition to the sealing element  144 , the hydraulic device  100  may include other sealing arrangements. For example, the hydraulic device  100  includes an end seal arrangement  186  disposed between the stationary housing  102  and the driven hub  104 . As illustrated in  FIGS. 3-5 , the end seal arrangement  186  includes two sealing seats (i.e., a first sealing seat  188  and a second sealing seat  190 ) formed on the circumference of a seal supporting ring  192 . The seal supporting ring  192  is disposed between the base portion  136  (i.e., the first housing end  132 ) of the stationary housing  102  and the first hub end  146  of the driven hub  104  such that the first sealing seat  188  abuts the base portion  136  of the stationary housing  102  and the second sealing seat  190  abuts the first hub end  146  of the driven hub  104 . The first and second sealing seats  188  and  190  receive sealing elements (e.g., O-ring seals, X-seals, and duo cone seals) thereon that provide sealing of the stationary housing  102  and the driven hub  104 , respectively, against the environment of the hydraulic device  100 . In addition to the end seal arrangement  186 , the hydraulic device  100  can include various seal arrangements at different locations. Examples of additional seal arrangements are disclosed in U.S. Patent Application Publication Nos. 2014/0023543 and 2014/0023544, the entirety of which are incorporated herein by reference. 
     Referring to  FIGS. 3 and 4 , the coupling mechanism  106  is configured to couple the drive shaft  130  to the driven hub  104  and transfer torque from the drive shaft  130  to the driven hub  104 . In some examples, the coupling mechanism  106  may include a coupler  200 , a brake piston  202 , a brake assembly  204 , and a spring assembly  206 . An example configuration of the coupling mechanism  106 , including the coupler  200 , the brake piston  202 , the brake assembly  204 , and the spring assembly  206 , is disclosed in more detail in U.S. Patent Application Publication Nos. 2014/0023543 and 2014/0023544, the entirety of which are incorporated herein by reference. 
     The coupler  200  is configured to couple the drive shaft  130  to the driven hub  104 . The coupler  200  and the driven hub  104  can rotate as a unit about the axis of rotation A when driven by the drive shaft  130 . The coupler  200  may be coupled to the driven hub  104  by a plurality of fasteners  212 , such as bolts and cams, that are circumferentially spaced around the axis of rotation A along a perimeter of the coupler  200 . The drive shaft  130  is coupled to the coupler  200  by a splined mechanical interface (e.g., a crown spline interface). An end plug  214  mounts to the coupler  200  and encloses the end of the shaft passage  140 . The end plug  214  can be threaded into the coupler  200  and can oppose an end of the drive shaft  130  in the shaft passage  140 . 
     The brake piston  202  operates as a lock piston as is known in the art. The brake piston  202  is configured to frictionally engage with and be carried with the coupler  200  and the driven hub  104 , thus rotating with the coupler  200  and the driven hub  104  as a unit when the coupler  200  and the driven hub  104  are rotated about the axis of rotation A by the drive shaft  130 . The brake piston  202  is configured to actuate the brake assembly  204 . 
     The brake assembly  204  includes a plurality of first brake pads  218  and a plurality of second brake pads  220 . The first brake pads  218  are configured to be mounted to the stationary housing  102  and the second brake pads  220  are configured to be carried by the driven hub  104  such that the second brake pads  220  rotate relative to the first brake pads  218  when the driven hub  104  rotate relative to the stationary housing  102 . The first and second brake pads  218  and  220  are interleaved relative to one another. When the brake assembly  204  is compressed, relative rotation is not allowed between the driven hub  104  and the stationary housing  102 . A plurality of serrations  222  may be disposed at least partially on interior diameters of the first brake pads  218  and engage with corresponding serrations on the stationary housing  102  to limit relative rotation between the first brake pads  218  and the stationary housing  102 . A plurality of tabs  224  may be disposed at least partially on outer diameters of the second brake pads  220  and fit within corresponding tab slots defined by the driven hub  104  to limit relative rotation between the driven hub  104  and the second brake pads  220 . 
     The spring assembly  206  operates to actuate the brake assembly  204 . In some examples, the spring assembly  206  can actuate the brake assembly  204  by applying a braking force through the brake piston  202  to the brake assembly  204  to compress the first and second brake pads  218  and  220  together such that relative rotation between the stationary housing  102  and the driven hub  104  is resisted by friction between the first and second brake pads  218  and  220 . The spring assembly  206  may be located between the brake piston  202  and the coupler  200 . In some example, the spring assembly  206  is compressed between the coupler  200  and the brake piston  202  such that the spring assembly  206  is preloaded with a spring force. In this configuration, the spring assembly  206  operates to normally urge the brake piston  202  against the brake assembly  204  to compress the brake assembly  204  in default. 
     Referring to  FIG. 4 , the hydraulic device  100  may include a brake chamber  230  formed on the brake assembly side of the brake piston  202  (i.e., the side opposite to the spring assembly  206 ). To release the brake, the brake chamber  230  may be pressurized. When the brake is released, rotation of the driven hub  104 , the coupler  200 , the brake piston  202 , the second brake pads  220 , and the spring assembly  206  is permitted relative to the stationary housing  102 . In some examples, the brake chamber  230  is pressurized by placing the brake chamber  230  in fluid communication with a pilot/charge pressure of a hydraulic circuit powering the hydraulic motor  108 . 
     The brake chamber  230  may be sealed with one or more seal arrangements including the sealing element  144 , as described herein. For example, the sealing element  144  is arranged to provide a sufficient sealing capacity for the brake chamber  230 . In some examples, the sealing element  144  riding on the sleeve insert  170  can be configured to withstand a pressure up to  750  psi while the end seal arrangement  186  can resist around 50 psi. The sealing element  178  can additionally be provided for sealing for the brake chamber  230 , as described above. 
     Referring to  FIGS. 2 and 4 , the hydraulic motor  108  is rear-piloted, and includes a motor housing assembly back-mounted to the stationary housing  102 . In some examples, the hydraulic motor  108  is a gerotor-type hydraulic motor. An example of the hydraulic motor  108  is disclosed in U.S. Patent Application Publication Nos. 2014/0023543 and 2014/0023544, the entirety of which are incorporated herein by reference. 
     Referring to  FIG. 7 , an example method  300  of assembling the hydraulic device  100  is disclosed in accordance with the principles of the present disclosure. In some examples, the method  300  may generally include operations  302 ,  304 ,  306  and  308 . 
     At the operation  302 , the sealing element  144  is mounted on the stationary housing  102 . For example, the sealing element  144  can be placed in the sealing groove  142  formed on the shaft portion  138  of the stationary housing  102 . 
     At the operation  304 , the driven hub  104  is installed over the stationary housing  102 . For example, the driven hub  104  is placed around the shaft portion  138  of the stationary housing  102  in an assembling direction D 1  ( FIG. 4 ) such that the inner wall  152  of the driven hub  104  is arranged over the sealing element  144  disposed on the shaft portion  138  of the stationary housing  102 . 
     At the operation  306 , the sleeve insert  170  is mounted within the driven hub  104 . For example, the sleeve insert  170  is engaged with the inner wall  152  of the driven hub  104  in the assembling direction D 1 . The sleeve insert  170  is disposed between the inner wall  152  of the driven hub  104  and the sealing element  144  disposed in the shaft portion  138  of the stationary housing  102 . As described herein, the sleeve insert  170  provides the riding surface  176  for the sealing element  144  as the driven hub  104  rotates relative to the stationary housing  102 . The sleeve insert  170  can be fixed to the inner wall  152  of the driven hub  104  by interference-fit. 
     At the operation  308 , the coupling mechanism  106  is secured to the driven hub  104  and the drive shaft  130  in the assembling direction D 1 . The coupling mechanism  106  is installed to couple the driven hub  104  to the drive shaft  130 . As described herein, the coupling mechanism  106  operates to couple the drive shaft  130  to the driven hub  104  such that torque from the drive shaft  130  is transferred to the driven hub  104  causing the driven hub  104  to rotate relative to the stationary housing  102 . 
     In addition to the operations  302 ,  304 ,  306  and  308 , the first bearing element  180  can be engaged around the shaft portion  138  of the stationary housing  102  in the assembling direction D 1  before the driven hub  104  is placed around the shaft portion  138  of the stationary housing  102 . In some examples, the first bearing element  180  can be arranged to abut the first axial face  154  of the inner wall  152  when the hydraulic device  100  is assembled. Further, the second bearing element  182  can be engaged around the shaft portion  138  of the stationary housing  102  in the assembling direction D 1  after the driven hub  104  is placed around the shaft portion  138  of the stationary housing  102 . Similarly to the first bearing element  180 , the second bearing element  182  can be arranged to abut the second axial face  156  of the inner wall  152  when the hydraulic device  100  is assembled. 
     The various examples described above are provided by way of illustration only and should not be construed to limit the scope of the present disclosure. Those skilled in the art will readily recognize various modifications and changes that may be made without following the example examples and applications illustrated and described herein, and without departing from the true spirit and scope of the present disclosure.