Hydraulic motor with improved multi-purpose passages

Abstract

An exemplary stator for a hydraulic motor includes a plurality of passages arranged in a circular array in a stator body and extending axially through the stator body, the plurality of passages configured to accommodate each bolt therethrough while allowing fluid to flow through each passage around each bolt disposed therein, the passages comprising compound first and second bores, the first bore having a first diameter and the second bore having a second diameter greater than the first diameter.

Description

[Technical Field]

[0001] The present invention relates to a hydraulic motor with an improved multi-purpose passage. (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority to U.S. Provisional Patent Application No. 63 / 479,762, filed January 13, 2023, the entire contents of which are incorporated herein by reference as if fully set forth herein. [Background technology]

[0002] A hydraulic motor may be configured to receive a fluid as an input and provide high-torque rotary motion as an output. Such a hydraulic motor may include a gear set configured to cooperate to define a fluid chamber. The chamber expands when hydraulically connected to a fluid source (e.g., a pump) and contracts when connected to a drain that returns the fluid to the fluid source or to a fluid reservoir. The expansion and contraction of the fluid chamber creates the rotary motion.

[0003] A hydraulic motor may have many passages for fluid flow, fasteners, etc. The geometry of such passages can affect the performance of the motor and the overall cost of manufacturing the motor. It is with respect to these and other considerations that the disclosure herein is presented. Summary of the Invention

[0004] The present disclosure describes an arrangement for a hydraulic motor with an improved multi-purpose passage.

[0005] In a first exemplary configuration, the present disclosure describes a stator for a hydraulic motor, the stator including: a stator body having (i) a central opening configured to receive a rotor therein; and (ii) a plurality of vanes configured to interact with lobes of the rotor; and a plurality of passages arranged in a circular array in the stator body and extending axially therethrough, the plurality of passages configured to receive respective bolts therethrough while allowing fluid to flow through each passage around each bolt disposed therein, the passages including compound first and second bores, the first bores having a first diameter and the second bores having a second diameter greater than the first diameter.

[0006] In a second exemplary configuration, the present disclosure describes a hydraulic motor including a stator of the first exemplary configuration and a rotor disposed within a central opening of the stator body, the rotor having a plurality of outer lobes configured to engage the plurality of vanes of the stator, whereby the plurality of vanes and the plurality of outer lobes define a fluid chamber between them configured to expand and contract as the rotor rotates within the stator.

[0007] In a third exemplary configuration, the present disclosure describes a hydrostatic transmission including a pump configured to provide fluid and a hydrostatic motor of the second exemplary configuration fluidly coupled to the pump and configured to receive fluid from the pump.

[0008] The above summary is for purposes of illustration only and is not intended to be in any way limiting. In addition to the exemplary aspects, configurations, and features described above, further aspects, configurations, and features will become apparent by reference to the drawings and the following detailed description. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional side view of a hydraulic motor according to an exemplary configuration. [Figure 2]FIG. 2 is an exploded perspective view of the hydraulic motor of FIG. 1 according to an exemplary configuration. [Figure 3] FIG. 2 is another cross-sectional view of a hydraulic motor according to an exemplary configuration. [Figure 4] 1 is a schematic partial side view of a rotor set assembly with projected fluid flow passages according to an exemplary configuration; [Figure 5] 1 is a cross-sectional view of a stator including passages having a substantially elliptical shape according to an exemplary configuration; [Figure 6] 1 is a cross-sectional view of a stator 146 including a passageway having two holes of a compound profile according to an exemplary configuration. [Figure 7] FIG. 7 is an enlarged partial cross-sectional view of the stator shown in FIG. 6 according to an exemplary configuration. [Figure 8] 8 is an enlarged partial cross-sectional view of FIG. 7 with a bolt disposed in a passageway of the stator according to an exemplary configuration. DETAILED DESCRIPTION OF THE INVENTION

[0010] An exemplary low-speed, high-torque (LSHT) hydraulic motor (e.g., a gerotor or gerotor hydraulic motor) has multiple passages, each with a fastener (e.g., a bolt) disposed therethrough, that allow fluid to flow therethrough. Such passages may have complex shapes and may require multiple machining steps to form. Such complex shapes and machining can be costly and present construction challenges. Therefore, it may be desirable to configure such passages in a shape that is less expensive to manufacture while still effectively providing fluid flow and allowing the fastener to perform its intended function (e.g., torque transmission and axial retention of various components of the motor).

[0011] Disclosed herein are systems, assemblies, hydraulic motors, and methods relating to hydraulic motors with improved multi-purpose passages. The passages are configured to accommodate each bolt therethrough while allowing fluid to flow through each passage around each bolt disposed therein. Each passage includes a compound first and second bore, the first bore having a first diameter and the second bore having a second diameter greater than the first diameter.

[0012] Figure 1 shows a cross-sectional side view of a hydraulic motor 100 according to an exemplary configuration, and Figure 2 shows an exploded perspective view of the hydraulic motor 100. Figures 1 and 2 will be described together.

[0013] Hydraulic motor 100 includes an end plate 102, a manifold 104, a rotor set assembly 106, a wear plate 108, a housing 110, a drive assembly 112, and a longitudinal axis 114. End plate 102, manifold 104, rotor set assembly 106, wear plate 108, housing 110, and drive assembly 112 may each be generally cylindrical, as shown in FIG.

[0014] Although the components of the hydraulic motor 100 are shown as separate components, in other configurations, some of these components may be integrated with one another. Furthermore, the hydraulic motor 100 may be a separate structure from other hydraulic components in the hydraulic circuit in which it is used, or it may be integrated with other components in the hydraulic circuit and reside in a common housing, or it may be bolted to such other components. For example, the hydraulic motor 100 may be bolted to a hydraulic pump, or it may be integrated with a hydraulic pump with a common housing. Such a motor and pump assembly is sometimes referred to as a hydrostatic transmission.

[0015] The hydraulic motor 100 is driven by fluid from the hydraulic pump in a forward or reverse rotational direction about the longitudinal axis 114 of the hydraulic motor 100. In the example, the hydraulic motor 100 is configured such that the forward direction of the hydraulic motor 100 is counterclockwise when viewed longitudinally from the right end of the hydraulic motor 100 toward the left end in the perspective of FIG. 1 . When the terms counterclockwise and clockwise are used herein, this refers to the hydraulic motor 100 viewed from such a longitudinal direction. The reverse direction of the hydraulic motor 100 is clockwise. In the following, operation of the hydraulic motor 100 will be described in the forward direction, but a reverse rotational direction of the hydraulic motor 100 may be achieved by reversing the flow of hydraulic fluid through the hydraulic motor 100.

[0016] The end plate 102 of the hydraulic motor 100 includes a plurality of end plate bolt holes, such as holes 116, configured to receive bolts 118 (e.g., threaded bolts or any type of fastener). The bolts 118 secure or fasten the end plate 102, manifold 104, rotor set assembly 106, wear plate 108, and housing 110 together.

[0017] Hydraulic motor 100 includes a commutator 120 rotatably disposed within a stationary commutator ring 122. Manifold 104 includes several manifold plates configured as stationary plates, such as manifold plate 124, manifold plate 126, manifold plate 128, manifold plate 130, and manifold plate 132. Commutator 120 is configured to separate chamber 134 from chamber 136, shown in FIG.

[0018] The hydraulic motor 100 may be bidirectional. Thus, in one operating state, chamber 134 may act as an inlet chamber while chamber 136 may act as an outlet chamber. In a second operating state, chamber 134 may act as an outlet chamber while chamber 136 may act as an inlet chamber.

[0019] Each of the manifold plates 124-132 may include a plurality of fluid passages 138 and 140 (e.g., central holes) extending therethrough (including fluid passage 138a, fluid passage 138b, fluid passage 138c, fluid passage 138d, fluid passage 138e, fluid passage 138f, and fluid passage 138g). The fluid passages 138 may be referred to as apertures or windows and may be configured to terminate at a termination surface 142 of the manifold plate 132. Each of the manifold plates 124-132 also includes seven bolt holes 143, respectively, to receive the bolts 118 and provide fluid flow paths.

[0020] The commutator 120 is configured to be driven by a drive link 144, which may be considered part of the drive assembly 112. The rotor set assembly 106, the drive assembly 112, and the drive link 144 may collectively be referred to as the drive assembly. The drive link 144 causes the commutator 120 to move in an orbital path relative to the manifold plates 124-132, thereby opening and closing fluid communication between the chamber 134 and the fluid passage 138 and between the chamber 136 and the fluid passage 138.

[0021] Fluid passages 138 of manifold 104 are configured to supply high pressure working fluid to rotor set assembly 106 and receive low pressure return working fluid from rotor set assembly 106, thereby causing rotation of the output assembly, as described further below. End faces 142 of manifold plates 132 of manifold 104 are disposed in a plane perpendicular to longitudinal axis 114.

[0022] The rotor set assembly 106 includes a stator 146 and a rotor 148. The rotor 148 is configured to be rotatably disposed within an interior space or central opening of the stator 146. As shown in FIG. 1 , the stator 146 and the rotor 148 each include an end face 149 that engages or interfaces with an end face 142 of the manifold plate 132 of the manifold 104. The stator 146 and the rotor 148 also each include another end face 150 that is parallel to the end face 149 and engages or interfaces with the wear plate 108.

[0023] Stator 146 may include a stator body 147 having respective bolt holes or passages, such as passage 151 shown in FIG. 1 , for receiving bolts 118. As will be explained in more detail below, fluid flows through passage 151 around bolts 118. Passage 151 is thus a multi-purpose passage that receives bolts 118 and allows fluid to flow therethrough.

[0024] Throughout this disclosure, the bolts may be referred to as a singular bolt 118 when referring to a specific bolt, or as a plurality of bolts 118 when referring collectively to all of the bolts arranged in a circular array around the hydraulic motor 100. Similarly, the passages in which the bolts 118 are located may be referred to as a singular passage 151 when referring to a specific passage, or as a plurality of passages 151 when referring collectively to all of the passages in which the bolts 118 are located.

[0025] The stator body 147 of the stator 146 also includes a central opening 152 that extends longitudinally along the longitudinal axis 114. The central opening 152 is generally circular in cross section.

[0026] A central opening 152 of stator 146 provides a plurality (e.g., seven) of roller cavities or roller pockets 153 configured as longitudinally extending semicircular pockets and arranged in a circular array around the inner surface of stator 146. Each of roller pockets 153 is configured to receive a longitudinally extending cylindrical roller, such as roller 154. Throughout this disclosure, a roller may be referred to as a singular roller 154 when a particular roller is being referred to, or as multiple rollers 154 when multiple rollers of stator 146 are being referred to collectively. Roller 154 may be configured to rotate freely within each roller pocket of stator 146.

[0027] The rollers 154, also referred to as vanes or vane rollers, are configured to operate as gear members inside the stator 146 formed within the central opening 152. The gear members operate as gear teeth that engage with the lobes of the rotor 148. However, it should be understood that other types of vanes other than rollers may also be used. While the hydraulic motor 100 shown and described herein is a gerotor hydraulic motor having roller-type vanes, the disclosure presented herein is applicable to other types of hydraulic motors having other types of vanes (e.g., gerotor motors having only a stator and rotor, where vanes are incorporated into the stator as internal teeth, instead of using rollers as vanes). Accordingly, the rollers 154 are also referred to as vanes of the stator 146. Each of the rollers 154 has a cylindrical outer surface between end faces 155 and 156, as shown in FIG. 1 .

[0028] 1 and 2, rotor 148 includes a longitudinally extending central opening 157 and a longitudinal axis 158. Longitudinal axis 158 is parallel to and radially offset from longitudinal axis 114 of stator 146. The surface of longitudinally extending central opening 157 of rotor 148 is generally circular in cross section and has a plurality of splines 159 for mating with corresponding external splines 160 located on drive link 144.

[0029] 2, the outer surface of the rotor 148 defines a plurality of outer lobes 162 (e.g., protrusions similar to gear teeth) configured to interact with the rollers 154 of the stator 146. The number of outer lobes 162 of the rotor 148 may be one less than the number of rollers 154 of the stator 146. As the rotor 148 rotates and orbits relative to the stator 146, the outer lobes 162 mesh with the rollers 154. In a counterclockwise rotational direction of the hydraulic motor 100, the interaction between the outer lobes 162 and the rollers 154 of the rotor 148 causes both the rotor 148 and the drive link 144 to rotate in a counterclockwise direction and both the rotor 148 and the commutator 120 to orbit in a clockwise direction.

[0030] Wear plate 108 includes bolt holes 163 to receive bolts 118. Wear plate 108 also includes a central opening 164 that extends longitudinally along longitudinal axis 114. Wear plate 108 also includes an end face 165 that is parallel to and engages or interfaces with end faces 150 of stator 146 and rotor 148.

[0031] The housing 110 includes a blind threaded bolt bore 166 configured to receive the threaded end of the bolt 118. The housing 110 also includes a central opening 167 disposed along the longitudinal axis 114.

[0032] Central opening 167 is stepped to accommodate suitable bearings, such as bearing 168, bearing 169, and bearing 170, for supporting drive assembly 112. Central opening 167 also supports suitable seals, such as seal 171 and seal 172, to prevent the escape or leakage of hydraulic fluid and the ingress of dirt and other foreign matter into central opening 167. An external groove in the exterior surface of housing 110 is configured to accommodate seal 173, which seals against the face of a hydraulic pump to which hydraulic motor 100 may be coupled.

[0033] Drive link 144 includes a commutator drive extension 174 configured to be received in a corresponding central opening in commutator 120, thereby driving commutator 120 in a clockwise orbital path relative to manifold 104. Drive link 144 also includes splines 175 that mesh with splines 176 formed on the inner surface of an output shaft 177 of drive assembly 112.

[0034] Drive link 144 is configured to be driven by engagement of splines 159 of rotor 148 with splines 160 of drive link 144. A central region of drive link 144 is supported in a central opening 164 in wear plate 108, which allows rotational and oscillating movement of drive link 144 relative to wear plate 108.

[0035] Splines 160 and splines 175 of drive link 144 can transfer torque from rotor 148 through drive link 144 to output shaft 177. In this manner, energy from the pressurized fluid driving rotor 148 is transferred to output shaft 177. A keyway 178 formed on the exterior surface of output shaft 177 is configured to connect output shaft 177 to a device driven by hydraulic motor 100 (e.g., a lawnmower wheel) via key 180, shown in FIG. 2. However, in the illustrated exemplary configuration, keyway 178 and key 180 may not be the primary method of torque transfer. Rather, as shown, output shaft 177 is tapered and can form a "taper lock" with the device driven by output shaft 177 (e.g., a self-retaining tapered structure).

[0036] The end plates 102 include grooves 179, and the manifold 104 also includes similar grooves 179, which are generally circular and configured to receive generally circular seals. Such seals can prevent leakage between the end plates 102 and the commutator ring 122, and between the commutator ring 122 and the manifold 104 and rotor set assembly 106.

[0037] FIG. 3 illustrates another cross-sectional view of the hydraulic motor 100 according to an exemplary configuration. As shown, the hydraulic motor 100 may have a first port 200 and a second port 202 in the housing 110. In one operating condition, the first port 200 may be an inlet port fluidly connected to a source of hydraulic fluid (e.g., a variable displacement hydraulic pump). In this operating condition, the output shaft 177 rotates in a first rotational direction (e.g., forward), and the second port 202 may be an outlet port through which fluid is discharged from the hydraulic motor 100. In FIG. 3, the first port 200 and the second port 202 are located in the housing 110. However, in other exemplary configurations, the ports may be located in the rear end cover of the motor. Thus, the port configuration is not meant to be limiting.

[0038] The hydraulic motor 100 is bidirectional as described above, and thus, in a second operating state, the second port 202 may be an inlet port fluidly connected to a source of hydraulic fluid, while the first port 200 may be an outlet port. In this operating state, the output shaft 177 rotates in a second rotational direction opposite the first rotational direction (e.g., reverse direction).

[0039] Assuming hydraulic motor 100 is operating in a first operating direction, fluid is received at first port 200 and then communicated through channel 204 to annular chamber 206 (in FIG. 3, the fluid is shown as a dotted pattern, with different pressure levels having different patterns). Fluid is then communicated from annular chamber 206 around bolt 118 through passage 151 (in stator 146) that houses bolt 118 to chamber 134. From chamber 134, fluid is communicated through a subset of fluid passages 138a-138g in manifold plates 124-132 to rotor set assembly 106, which causes rotor 148 to rotate, as described below with respect to FIG. 4.

[0040] Fluid discharged from rotor set assembly 106 flows through manifold 104 back to chamber 136. The fluid then flows back through manifold 104, around drive link 144, and then through fluid passage 208 to be communicated to second port 202.

[0041] Figure 4 is a schematic partial side view of rotor set assembly 106, showing fluid passages 138a-138g superimposed or projected onto one another in accordance with an exemplary configuration. Although not shown in the schematic view of Figure 4, rotor 148 includes a longitudinally extending central opening 157 and has splines 159 as described above. Also in Figure 4, the fluid is shown with a dot pattern, with different pressure levels having different patterns.

[0042] Stator 146 defines roller pockets 153 on an inner surface thereof, which receive rollers 154 therein. Rollers 154 of stator 146 and outer lobes 162 of rotor 148 operatively engage and cooperate to cooperatively define respective fluid chambers in rotor set assembly 106, such as fluid chamber 302, fluid chamber 304, fluid chamber 306, fluid chamber 308, fluid chamber 310, fluid chamber 312, and fluid chamber 314. Fluid chambers 302-314 are separated from one another by the effective moving contact between outer lobes 162 and rollers 154.

[0043] As rotor 148 rotates and orbits within stator 146, fluid chambers 302-314 expand and contract, respectively. Fluid chambers 302-314 may include portions of adjacent ones of fluid passages 138a-138g and may be fluidly connected to portions of adjacent ones of fluid passages 138a-138g. As a result, fluid chambers 302-314 may have fluid pressure levels that are substantially the same as the fluid pressure levels of corresponding or adjacent ones of fluid passages 138a-138g.

[0044] As an example illustrating the operation of hydraulic motor 100, the rotational and orbital motion of rotor 148 may be induced by a working fluid provided from first port 200 (see FIG. 3) through passage 151 to chamber 134 and directed from chamber 134 to fluid passages 138d, 138e, and 138f by commutator 120. As shown in FIG. 4, fluid passages 138d, 138e, and 138f are aligned with fluid chambers 308, 310, and 312, respectively. In this case, pressurized fluid causes fluid chambers 308, 310, and 312 to expand, which in turn causes rotor 148 to rotate in a counterclockwise direction.

[0045] 4, low pressure fluid is discharged from fluid chambers 302, 304, 306 and 314 and directed by commutator 120 through fluid passages 138a, 138b, 138c and 138g to chamber 136. This allows fluid chambers 302, 304, 306 and 314 to contract.

[0046] 1-2, as rotor 148 rotates, drive link 144 rotates with rotor 148 due to the engagement of splines 159, 160. Rotation of drive link 144 may then rotate output shaft 177 of hydraulic motor 100 due to the engagement of splines 175, 176. Output shaft 177 may be coupled to a wheel of a machine (e.g., a lawn mower) which, in turn, rotates the wheel to propel the machine.

[0047] As mentioned above, the passages 151 in the stator 146 have multiple purposes. They house the bolts 118 for torque resistance, allow fluid to flow around the bolts 118 to and from the first port 200, and act as a pressure vessel for pressurized fluid. As the rotor 148 rotates within the stator 146 and the outer lobes 162 of the rotor 148 engage the rollers 154, torque is applied to the stator 146. The bolts 118 bear at least a portion of this torque.

[0048] In other words, torque is transmitted from the stator 146 to the bolts 118. As such, it may be desirable to increase the number of bolts 118 so that the torque is distributed among a greater number of bolts. By having the passages 151 function as both fluid flow conduits and holes for the bolts 118, a greater number of bolts 118 can be used compared to a configuration in which separate holes are used for the bolts 118 and other passages are used for fluid flow in a given space.

[0049] Additionally, the bolts 118 axially fasten the components of the hydraulic motor 100. In particular, the bolts 118 hold the end plate 102, the commutator ring 122, the manifold 104, the rotor set assembly 106 (particularly the stator 146), and the wear plate 108 to the housing 110. Thus, the bolts 118 also bear the axial load that fastens these components together, thereby preventing the hydraulic motor 100 from coming apart during operation.

[0050] As such, the configuration or shape of the passage 151 can affect the performance of the hydraulic motor 100. It may be desirable to configure the passage 151 to have a larger cross-sectional area around the bolt 118, thereby accommodating a larger fluid flow rate, while reducing the pressure drop as the fluid flows through the passage 151. It may also be desirable to configure the passage 151 to reduce the manufacturing costs of the hydraulic motor 100.

[0051] 5 illustrates a cross-sectional view of stator 146 including passages, such as passage 500, having a substantially elliptical shape according to an exemplary configuration. To reduce clutter, rollers 154 are not shown. Passage 500 represents passage 151, for example, as described above. Passages 500 are formed in a circular array around stator body 147, as shown.

[0052] The passages may be referred to as a singular passage 500 when referring to a specific passage, or as multiple passages 500 when referring collectively to multiple passages in the stator 146. The passages 500 extend through the stator 146 and receive the bolts 118 therethrough. For purposes of illustration, only one passage is labeled, and the bolts 118 are indicated by dashed lines as they are disposed through the passages.

[0053] As used herein, the term "shape" of passage 500 refers to the cross-sectional profile of passage 500. As shown in FIG. 5, passage 500 has straight sides and circular radial ends, giving passage 500 a substantially elliptical shape. As shown, bolt 118 is displaced radially inward toward the radially inward end of passage 500 (i.e., toward the center of stator 146). A flow region 502 formed around bolt 118 (e.g., radially outward from bolt 118) allows fluid to flow through passage 500.

[0054] 5, thickness 504 separates passageway 500 from the edge or boundary of roller pocket 153 that houses roller 154. Thickness 504 is related to the strength of stator 146, i.e., the ability of stator 146 to withstand forces and torques.

[0055] A two-step process may be implemented to machine the passages 500 during the manufacture of the stator 146. In the first step, a drill may be used to create a circular hole through the stator 146. Then, a broaching burr may be used to form the oval shape of the passages 500.

[0056] In some instances, as the broaching burr wears, it can be difficult to maintain the shape and dimensions of the passageway 500 over time. Additionally, broaching machinery is expensive. Furthermore, the broaching step limits the ability to configure the passageway 500 with different shapes that improve fluid flow while reducing manufacturing costs. Therefore, it may be desirable to configure the passageway of the stator 146 to have different profiles or shapes that improve fluid flow area while reducing manufacturing costs and maintaining the thickness 504.

[0057] 6 illustrates a cross-sectional view of stator 146 including a compound-profile, two-hole passageway 600 according to an exemplary configuration. To reduce clutter, rollers in some roller pockets 153 are shown, rather than rollers 154 in all roller pockets. Passageway 600, which may represent passageway 151, as discussed above, is formed in a circular array around stator body 147, as shown.

[0058] Passages 600 extend axially through the stator body 147 and receive the bolts 118 therethrough. For purposes of illustration, only one passage 600 is labeled, and the bolts 118 are shown in dashed lines as they are disposed through the passages 600.

[0059] Figure 7 shows an enlarged partial cross-sectional view of an exemplary configuration of the stator 146 shown in Figure 6. In particular, Figure 7 provides an enlarged view of one of the passages 600 to show details of the passage 600.

[0060] 7, the passageway 600 has a shape that is a composite of two circular holes, a first hole 700 and a second hole 702, that overlap each other to form the profile of the passageway 600. The first hole 700 is smaller than the second hole 702 (i.e., the diameter of the first hole 700 is smaller than the diameter of each of the second holes 702).

[0061] The centers 704 of the first holes 700 (and the centers of all of the first holes in each of the passages 600) are disposed on a first circle 706, while the centers 708 of the second holes 702 (and the centers of all of the second holes in each of the passages 600) are disposed on a second circle 710. The second circle 710 has a larger diameter than the first circle 706. In particular, referring to both FIGS. 6 and 7 , the radius of the second circle 710 (e.g., the distance from the center 602 of the stator 146 to the second circle 710) is larger than the radius of each of the first circles 706 (i.e., the distance from the center 602 of the stator 146 to the first circle 706). Thus, the centers 708 of the second holes 702 are displaced radially outward from the centers 704 of the first holes 700.

[0062] By way of example, the diameter of the first hole 700 may be approximately 0.396 inches, while the diameter of the second hole 702 may be approximately 0.46 inches. Thus, the ratio of the diameter of the first hole 700 to the diameter of the second hole 702 may be approximately 1.16. The diameter of the first circle 706 may be approximately 3.5 inches, while the diameter of the second circle 710 may be approximately 3.696 inches. These figures are merely exemplary, and other dimensions and ratios may be implemented. For example, larger motors may have larger holes and circles.

[0063] FIG. 8 illustrates a partial, enlarged cross-sectional view of FIG. 7 with the bolt 118 positioned in the passage 600 according to an exemplary configuration. In FIG. 8, the bolt 118 is shown in dashed lines. In the exemplary configuration of FIG. 8, the bolt 118 is displaced radially inward toward the first hole 700. For example, the center of the bolt 118 may generally coincide with the center 704 of the first hole 700 shown in FIG. 8. As used herein, the term "generally coincide" indicates that the center of the bolt 118 coincides with the center of the first hole 700 or is within a threshold distance (e.g., 1-2 mm) of the center of the first hole 700.

[0064] Flow regions 800 are formed around bolt 118 of second hole 702 (e.g., radially outward from bolt 118), which allows fluid to flow through passageway 600. In an example, the cross-sectional area of ​​flow region 502 in the configuration of FIG. 5 may be approximately 0.19 square inches, while the cross-sectional area of ​​each of flow regions 800 may be approximately 0.192 square inches while maintaining thickness 504.

[0065] 6-8 may provide a larger flow area compared to the configuration of FIG. 5, while still maintaining a similar thickness to thickness 504. Thus, the larger flow area may be obtained without impacting the strength of stator 146.

[0066] Furthermore, machining of passageway 600 can be less expensive than machining of passageway 500. Notably, passageway 600 does not require a broaching step and may be performed in two drilling steps. For example, a drill may be centered on center 704 of first hole 700, and first hole 700 is drilled using a first drill bit. The drill may then be displaced radially outward and centered on center 708, and second hole 702 is drilled using a larger second drill bit. This process may simplify and reduce the cost of machining passageways in stator 146 that accommodate bolts 118 while allowing fluid to flow therethrough (e.g., passageways 151, 600).

[0067] In the above detailed description, various features and operations of the disclosed system have been described with reference to the accompanying drawings. The exemplary configurations described herein are not meant to be limiting. Particular aspects of the disclosed system may be arranged and combined in a wide variety of different configurations, all of which are contemplated herein.

[0068] Furthermore, unless the context suggests otherwise, features shown in each figure may be used in combination with one another. Thus, the drawings should generally be viewed as component aspects of one or more overall configurations, with the understanding that not all illustrated features are necessary for each configuration.

[0069] Additionally, recitations of elements, blocks, or steps in the specification or claims are for the purpose of clarity, and therefore should not be construed as requiring or implying that these elements, blocks, or steps conform to a particular configuration or be performed in a particular order.

[0070] Furthermore, a device or system may be used or configured to perform the functions depicted in the figures. In some cases, device and / or system components may be configured to perform a function such that the components are actually configured and structured (using hardware and / or software) to enable such performance. In other examples, device and / or system components may be adapted to perform a function, be capable of performing a function, or be configured to be suitable for performing a function, such as when operated in a particular manner.

[0071] The term "substantially" or "about" means that the stated characteristic, parameter or value need not be exactly achieved, but that deviations or variations, including, for example, tolerances, measurement errors, limitations in measurement accuracy and other factors known to those skilled in the art, may occur in an amount that does not prevent the characteristic from having its intended effect.

[0072] The configurations described herein are for illustrative purposes only. Thus, those skilled in the art will recognize that other configurations and other elements (e.g., machines, interfaces, operations, sequences, groupings of operations, etc.) can be substituted, and that some elements may be omitted entirely, depending on the desired results. Furthermore, many of the described elements are functional entities that may be implemented as individual or distributed components, or in combination with other components, in any suitable combination and location.

[0073] While various aspects and configurations are disclosed herein, other aspects and configurations will be apparent to those skilled in the art. The various aspects and configurations disclosed herein are for illustrative purposes only and are not intended to be limiting, with the true scope being indicated by the following claims and the full scope of equivalents to which such claims are entitled. Additionally, the terminology used herein is for the purpose of describing particular configurations only and is not intended to be limiting.

[0074] Accordingly, embodiments of the present disclosure may relate to one of the following listed exemplary embodiments (EEE):

[0075] EEE1 is a stator for a hydraulic motor comprising: a stator body having (i) a central opening configured to accommodate a rotor therein; and (ii) a plurality of vanes configured to interact with lobes of the rotor; and a plurality of passages arranged in a circular array in the stator body and extending axially therethrough, the plurality of passages configured to accommodate respective bolts therethrough while allowing fluid to flow through each passage around each bolt disposed therein, the passages comprising compound first and second bores, the first bores having a first diameter and the second bores having a second diameter greater than the first diameter.

[0076] EEE2 is a stator of EEE1, in which the first hole and the second hole overlap each other to form a passage.

[0077] EEE3 is the stator of EEE2, with the centers of the second holes displaced radially outward from the centers of each of the first holes relative to the center of the stator body.

[0078] EEE4 is a stator of EEE3 configured such that each bolt is positioned in the passageway such that the center of each bolt is generally aligned with the center of each of the first holes.

[0079] EEE5 is the stator of EEE4 with passages providing flow areas around each bolt within the second bore that allow fluid to flow through the passages.

[0080] EEE6 is a hydraulic motor comprising: a stator comprising: (i) a stator body having a central opening; (ii) a plurality of vanes; and (iii) a plurality of passages arranged in a circular array in the stator body and extending axially therethrough, the plurality of passages configured to accommodate respective bolts therethrough while allowing fluid to flow through each passage around each bolt disposed therein, the passages comprising compound first and second bores, the first bores having a first diameter and the second bores having a second diameter greater than the first diameter; and a rotor disposed within the central opening of the stator body, the rotor comprising a plurality of outer lobes configured to engage the plurality of vanes of the stator, whereby the plurality of vanes and the plurality of outer lobes define fluid chambers between them configured to expand and contract as the rotor rotates within the stator.

[0081] EEE7 is a hydraulic motor of EEE6, in which the first hole and the second hole overlap each other to form a passage.

[0082] EEE8 is the hydraulic motor of EEE7, wherein the centres of the second holes are displaced radially outward from the centres of each of the first holes relative to the centre of the stator body.

[0083] EEE9 is the hydraulic motor of EEE8 configured to position each bolt in the passage so that the center of each bolt is generally aligned with the center of each of the first holes.

[0084] EEE10 is the hydraulic motor of EEE9, wherein the passages include a flow area around each bolt within the second bore that allows fluid to flow through the passages.

[0085] EEE11 is the hydraulic motor of any of EEE6 to EEE10, wherein the center of the first hole of each of the plurality of passages is located on a first circle and the center of the second hole of each of the plurality of passages is located on a second circle that is radially displaced outward from the first circle relative to the center of the stator body.

[0086] EEE12 is any of the hydraulic motors EEE6 to EEE11, further comprising a manifold joining the stator and the rotor, the manifold comprising a plurality of fluid passages configured to communicate fluid contained therein through the plurality of passages in the stator to the fluid chambers.

[0087] EEE13 is a hydraulic motor of EEE12, further comprising a housing that accommodates respective bolts for fastening the stator, rotor, and manifold to the housing, and a first port and a second port, whereby fluid accommodated in the first port passes through multiple passages in the stator and then through the manifold to be communicated to a fluid chamber, and fluid discharged from the fluid chamber is communicated to the second port through the manifold.

[0088] EEE14 is a hydrostatic transmission comprising: a pump configured to provide a fluid; and a hydrostatic motor fluidly coupled to the pump and configured to receive fluid from the pump, the hydrostatic motor comprising a stator having (i) a stator body having a central opening; (ii) a plurality of vanes; and (iii) a plurality of passages disposed in a circular array in the stator body and extending axially therethrough, the plurality of passages allowing fluid to flow from the pump through each passage around each bolt disposed in the passage while receiving a respective bolt therethrough. a stator including a plurality of passages configured to rotate within the stator body, the passages including compound first and second holes, the first hole having a first diameter and the second hole having a second diameter greater than the first diameter; and a rotor disposed within a central opening of the stator body, the rotor including a plurality of outer lobes configured to engage a plurality of vanes of the stator, whereby the plurality of vanes and the plurality of outer lobes define fluid chambers between them configured to expand and contract as the rotor rotates within the stator.

[0089] EEE15 is a hydrostatic transmission of EEE14, in which the first holes and second holes overlap each other to form a passage, and the centers of the second holes are displaced radially outward from the centers of each of the first holes relative to the center of the stator body.

[0090] EEE16 is the hydrostatic transmission of EEE15 configured such that each bolt is positioned in the passage such that the center of each bolt generally coincides with the center of each of the first holes.

[0091] EEE17 is the hydrostatic transmission of EEE16, wherein the passage includes a flow area around each bolt within the second bore that allows fluid to flow through the passage.

[0092] EEE18 is the hydrostatic transmission of any of EEE14 to 17, wherein the center of the first hole of each of the plurality of passages is disposed on a first circle and the center of the second hole of each of the plurality of passages is disposed on a second circle that is displaced radially outward from the first circle relative to the center of the stator body.

[0093] EEE19 is the hydrostatic transmission of any of EEE14 to 18, further comprising a manifold joining the stator and the rotor, the manifold comprising a plurality of fluid passages configured to communicate fluid contained therein through the plurality of passages in the stator to the fluid chamber.

[0094] EEE20 is the hydrostatic transmission of EEE19, in which the hydrostatic motor further comprises a housing that accommodates respective bolts for fastening the stator, the rotor, and the manifold to the housing, and a first port and a second port, in which fluid accommodated in the first port passes through a plurality of passages in the stator and then through the manifold to be communicated to the fluid chamber, and in which fluid discharged from the fluid chamber is communicated to the second port through the manifold.

Claims

1. A stator for a hydraulic motor, a stator body comprising: (i) a central opening configured to receive a rotor therein; and (ii) a plurality of vanes configured to interact with lobes of the rotor; a plurality of passages arranged in a circular array in the stator body and extending axially through the stator body, the plurality of passages configured to receive a respective bolt therethrough while allowing fluid to flow therethrough around each bolt disposed therein, the passages comprising compound first and second bores, the first bore having a first diameter and the second bore having a second diameter greater than the first diameter; A stator having

2. The stator of claim 1 , wherein said first hole and said second hole overlap each other to define said passageway.

3. The stator of claim 2 , wherein the centers of the second holes are offset radially outward from the centers of each of the first holes relative to the center of the stator body.

4. The stator of claim 3 , wherein each of the bolts is configured to be positioned in the passageway such that a center of each of the bolts is substantially aligned with a center of each of the first holes.

5. The stator of claim 4 , wherein the passage includes a flow area around each of the bolts within the second bore that allows fluid to flow through the passage.

6. A hydraulic motor, a stator including: (i) a stator body having a central opening; (ii) a plurality of vanes; and (iii) a plurality of passages disposed in a circular array in the stator body and extending axially through the stator body; the plurality of passages are configured to receive a respective bolt therethrough while allowing fluid to flow through each passage around each bolt disposed therein, the passages comprising a compound first hole and a compound second hole, the first hole having a first diameter and the second hole having a second diameter greater than the first diameter; the hydraulic motor further includes a rotor disposed within the central opening of the stator body; the rotor comprising a plurality of outer lobes configured to engage the plurality of blades of the stator, whereby the plurality of blades and the plurality of outer lobes define fluid chambers therebetween configured to expand and contract as the rotor rotates within the stator. Hydraulic motor.

7. 7. A hydraulic motor according to claim 6, wherein said first hole and said second hole overlap each other to define said passageway.

8. 8. A hydraulic motor according to claim 7, wherein the centers of said second holes are offset radially outward from the centers of each of said first holes relative to the center of said stator body.

9. 9. The hydraulic motor of claim 8, wherein each of the bolts is configured to be positioned in the passageway such that the center of each of the bolts is substantially aligned with the center of each of the first holes.

10. 10. The hydraulic motor of claim 9, wherein the passage includes a flow area around each of the bolts within the second bore that allows fluid to flow through the passage.

11. 7. The hydraulic motor of claim 6, wherein a center of a first hole of each of said plurality of passages is disposed on a first circle and a center of a second hole of each of said plurality of passages is disposed on a second circle that is offset radially outward from said first circle relative to a center of said stator body.

12. 7. The hydraulic motor of claim 6, further comprising a manifold joining the stator and the rotor, the manifold including a plurality of fluid passages configured to channel fluid received through the plurality of passages in the stator to the fluid chambers.

13. The hydraulic motor is a housing that accommodates the bolts for fastening the stator, the rotor, and the manifold; a first port and a second port; and Fluid received at the first port flows through the plurality of passages in the stator and then through the manifold to the fluid chamber, and fluid expelled from the fluid chamber flows through the manifold to the second port.

13. The hydraulic motor of claim 12.

14. A hydrostatic transmission, a pump configured to provide a fluid; a hydraulic motor fluidly connected to the pump and configured to receive fluid from the pump; and The hydraulic motor includes a stator including: (i) a stator body having a central opening; (ii) a plurality of vanes; and (iii) a plurality of passages disposed in a circular array on the stator body and extending axially therethrough; the plurality of passages are configured to receive a respective bolt therethrough while allowing fluid to flow from the pump through each passage around each bolt disposed therein, the passages comprising a compound first bore and a compound second bore, the first bore having a first diameter and the second bore having a second diameter greater than the first diameter; the hydraulic motor further includes a rotor disposed within the central opening of the stator body; the rotor comprising a plurality of outer lobes configured to engage the plurality of blades of the stator, whereby the plurality of blades and the plurality of outer lobes define fluid chambers therebetween configured to expand and contract as the rotor rotates within the stator. Hydrostatic transmission.

15. 15. The hydrostatic transmission of claim 14, wherein the first holes and the second holes overlap to form the passageway, and the centers of the second holes are offset radially outward from the centers of each of the first holes relative to the center of the stator body.

16. 16. The hydrostatic transmission of claim 15, wherein each said bolt is configured to be positioned in said passageway such that a center of each said bolt is substantially aligned with a center of each said first hole.

17. 17. The hydrostatic transmission of claim 16, wherein the passage includes a flow area around each of the bolts within the second bore that allows fluid to flow through the passage.

18. 15. The hydrostatic transmission of claim 14, wherein a center of a first hole of each of the plurality of passages is disposed on a first circle and a center of a second hole of each of the plurality of passages is disposed on a second circle that is offset radially outward from the first circle relative to the center of the stator body.

19. 15. The hydrostatic transmission of claim 14, further comprising a manifold joining the stator and the rotor, the manifold including a plurality of fluid passages configured to channel fluid received through the plurality of passages in the stator to the fluid chamber.

20. The hydraulic motor is a housing that accommodates the bolts for fastening the stator, the rotor, and the manifold; a first port and a second port; and Fluid received at the first port flows through the plurality of passages in the stator and then through the manifold to the fluid chamber, and fluid expelled from the fluid chamber flows through the manifold to the second port.

20. The hydrostatic transmission of claim 19.

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