WO2025147305A1 - Hydraulic pump with an attenuator - Google Patents

Abstract

An example pump assembly includes: a housing; a port block coupled to the housing and having an inlet port and an outlet port; a pump disposed within the housing, wherein the pump draws fluid through the inlet port and discharges fluid through the outlet port; a pressure control valve that regulates pressure level of fluid discharged by the pump through the outlet port; one or more fluid passages that communicate a fluid signal from fluid discharged by the pump to the pressure control valve; an attenuator chamber; and an attenuator orifice that fluidly couples the one or more fluid passages to the attenuator chamber.

Description

Hydraulic Pump with an Attenuator

CROSS REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority to U.S. Provisional Patent Application No. 63/616,792, filed on January 1, 2024, and U.S. Provisional Patent Application No. 63/682,396, filed on August 13, 2024, the entire contents of all of which are herein incorporated by reference as if fully set forth in this description.

BACKGROUND

[0002] In many applications, fluid flow passages exhibit natural (resonant) frequencies as fluid flows therein. For example, within a pump drilled fluid passages that have long lengths relative to their diameters are commonly used to communicate discharge fluid to the pump’s control valve(s) or to a pump outlet port. Due to the physical characteristics of these fluid passages, their natural frequencies and the resulting high amplitude pressure ripples in fluid flowing within the fluid passages are often in the range of 1000-2000 Hertz (Hz).

[0003] Spools of the pump’s control valve(s), being of small mass, can respond (e.g., vibrate or oscillate) to these high frequency ripples in that frequency range. As a result, a high frequency whistling sound caused by the erratic flow (from the ripples) across the valve spool may occur. This whistling sound can be loud enough to cause annoyance to a machine operator. Other negative effects from the resonant pressure ripples include damage to internal components of the pump, wear of sliding valve components, and damage to elastomeric seals, as examples.

[0004] Some conventional pumps may have a ripple chamber configured to reduce ripples in the discharge flow of the pump by reducing the rate of flow from the discharge port to a piston chamber that is in the pre-compression zone. The ripple chamber acts like an accumulator in the pre-compression zone, so the transition is smoothed, which results in reduced flow ripple magnitude which generally translates to a quieter hydraulic system. However, such ripple chambers do not address resonant pressure ripples in drilled fluid passages, nor do they address the above-mentioned spool oscillation or the whistling resulting therefrom.

[0005] In most applications, it is not possible to configure the fluid passages to cause their natural frequency to be below or above that frequency range. Particularly, it might not be possible to change the geometry of the fluid passages to move the resonant frequency high enough and avoid the negative consequences mentioned above.

[0006] It may thus be desirable to attenuate ripples in fluid passages (e.g., fluid passages within a pump) without affecting the size of a device (e.g., pump) having these passages, while minimizing cost impact. It is with respect to these and other considerations that the disclosure made herein is presented.

SUMMARY

[0007] The present disclosure describes implementations that relate to a hydraulic pump with an attenuator.

[0008] In a first example implementation, the present disclosure describes a pump assembly. The pump assembly includes: a housing; a port block coupled to the housing and having an inlet port and an outlet port; a pump disposed within the housing, wherein the pump draws fluid through the inlet port and discharges fluid through the outlet port; a pressure control valve that regulates pressure level of fluid discharged by the pump through the outlet port; one or more fluid passages that communicate a fluid signal from fluid discharged by the pump to the pressure control valve; an attenuator chamber; and an attenuator orifice that fluidly couples the one or more fluid passages to the attenuator chamber.

[0009] In a second example implementation, the present disclosure describes a hydraulic system including the pump assembly of the first example implementation.

[0010] In a third example implementation, the present disclosure describes a method of operating the pump assembly of the first example implementation and/or the hydraulic system of the second example implementation.

[0011] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, implementations, and features described above, further aspects, implementations, and features will become apparent by reference to the figures and the following detailed description. BRIEF DESCRIPTION OF THE FIGURES

[0012] The novel features believed characteristic of the illustrative examples are set forth in the appended claims. The illustrative examples, however, as well as a preferred mode of use, further objectives and descriptions thereof, will best be understood by reference to the following detailed description of an illustrative example of the present disclosure when read in conjunction with the accompanying Figures.

[0013] Figure 1 illustrates a perspective view of a pump assembly, according to an example implementation.

[0014] Figure 2 illustrates another perspective view of the pump assembly of Figure 1 from a different angle, according to an example implementation.

[0015] Figure 3 illustrates a rear view of the pump assembly of Figure 1, according to an example implementation.

[0016] Figure 4 illustrates a side view of the pump assembly of Figure 1, according to an example implementation.

[0017] Figure 5 illustrates a top view of the pump assembly of Figure 1, according to an example implementation.

[0018] Figure 6 illustrates a cross-sectional side view of the pump assembly of Figure 1, according to an example implementation.

[0019] Figure 7 illustrates a cross-sectional view of the pump assembly of Figure 1, according to an example implementation.

[0020] Figure 8 illustrates a cross-sectional view of the pump assembly of Figure 1, according to an example implementation. [0021] Figure 9 illustrates another cross-sectional view of the pump assembly of Figure 1 , according to an example implementation.

[0022] Figure 10 illustrates a cross-sectional view of a pressure control valve of the pump assembly of Figure 1, according to an example implementation.

[0023] Figure 11 illustrates an enlarged view of the cross-section depicted in Figure 8, according to an example implementation.

[0024] Figure 12 illustrates a schematic of a hydraulic system including the pump assembly of Figure 1, according to an example implementation.

[0025] Figure 13 is a graph depicting simulation results showing pressure amplitude versus frequency with and without an attenuator configuration, according to an example implementation.

[0026] Figure 14 is a graph depicting simulation results showing pressure amplitude versus time with and without the attenuator configuration, according to an example implementation.

[0027] Figure 15 is a flowchart of a method of operating the pump assembly of Figure 1 or the hydraulic system of Figure 12, according to an example implementation.

DETAILED DESCRIPTION

[0028] Within examples, disclosed herein are systems and methods associated with a pump having features for dampening pressure ripples in fluid passages within the pump assembly. The disclosed pump assembly involves adding an attenuator configuration to dampen pressure ripples or pulsations, thereby reducing vibrations and noise. The disclosed attenuator configuration might not increase cost or the overall size of the pump assembly. Further, in an example, the attenuator configuration can include an attenuator chamber that is accessible through a diagnostic (gauge) port in a housing of the pump assembly to provide an indication of pressure level and waveform within the pump assembly.

[0029] Figure 1 illustrates a perspective view of a pump assembly 100, Figure 2 illustrates another perspective view of the pump assembly 100 from a different angle, Figure 3 illustrates a rear view of the pump assembly 100, Figure 4 illustrates a side view of the pump assembly 100, and Figure 5 illustrates a top view of the pump assembly 100, according to an example implementation. Figures 1-5 are described together.

[0030] The pump assembly 100 includes a housing 102 (e.g., a casting) and a port block 104 coupled to the housing 102 via a plurality of fasteners such as fastener 106. Seals can be disposed at the interface between the housing 102 and the port block 104 to prevent leakage.

[0031] The housing 102 has a case drain port 108. During operation of a pump disposed within the pump assembly 100 as described below, excess internal leakage fluid from the pump is directed to the case drain port 108, which can be fluidly coupled to a tank or fluid reservoir (e.g., fluid reservoir 109 shown in Figure 12) containing fluid at low pressure (e.g., atmospheric pressure). The term “fluidly coupled” is used throughout herein to indicate that fluid can flow or be communicated between two fluid passages, chambers, ports, or openings. [0032] The port block 104 includes an inlet port 110 and a discharge or outlet port 112. For example, the inlet port 110 can be fluidly coupled to the fluid reservoir 109 (see Figure 12), while the outlet port 112 can be fluidly coupled to a fluid consumer device 113 (see Figure 12), such as a hydraulic actuator (e.g., cylinder actuator or hydraulic motor).

[0033] The pump assembly 100 has an input shaft 114, which is coupled to a rotating group of the pump disposed within the pump assembly 100 as described below. As the input shaft 114 rotates, the pump draws fluid through the inlet port 110 and discharges fluid through the outlet port 112.

[0034] The pump assembly 100 further includes a pressure control valve 116 (e.g., a hydromechanical pressure compensator valve). As described in more details below, the pressure control valve 116 is configured as a pressure limiting control or pressure cut-off device that regulates the pressure level of fluid discharged through the outlet port 112. Particularly, the pressure control valve 116 senses the pressure level of the fluid being discharged and adjusts the fluid flow rate to maintain a consistent pressure level, even when demand for fluid flow changes. This helps to prevent the pump from being overloaded and ensures the system operates safely and efficiently.

[0035] Figure 6 illustrates a cross-sectional side view of the pump assembly 100, according to an example implementation. The cross-sectional plane of Figure 6 is labelled in Figure 3. The pump assembly 100 includes a pump 118, configured as a variable displacement piston pump. A variable displacement piston pump is described herein as an example. Any other type of variable displacement pump with pressure ripple can make use of the attenuator configuration described herein. [0036] The pump 118 has a swashplate 120 and a rotating group 122 mounted to the input shaft 114 and rotatable therewith. As shown, the input shaft 114 is supported via a first bearing 124 and a second bearing 126 disposed within the housing 102 and the port block 104 to facilitate rotation of the input shaft 114.

[0037] The rotating group 122 includes a cylinder block 128 defining a plurality of cylinders such as cylinder 130 therein. The rotating group 122 further includes a plurality of pistons, such as piston 132, disposed in a circular array within the respective cylinders of the cylinder block 128. For example, the piston 132 is disposed within a chamber 133 formed within the cylinder 130. The pistons (e.g., the piston 132) are each coupled to a slipper 134, which allows the pistons to slip across the surface of the swashplate 120 as the rotating group 122 rotates.

[0038] The input shaft 114 can be coupled to an output shaft of a prime mover (e.g., electric motor or engine). As the input shaft 114 rotates, the rotating group 122 rotates therewith. As the rotating group 122 rotates, and when the swashplate 120 is disposed at an angle as shown in Figure 6, the pistons reciprocate within their respective cylinders. For example, the piston 132 can reciprocate within the cylinder 130 when the rotating group 122 rotates and the swashplate 120 is angled.

[0039] By varying the angle of the swashplate 120, a continuous ratio from zero flow to a maximum fluid flow rate can be obtained. The angle of the swashplate 120 relative to the input shaft 114 can be changed via a control piston 136 interacting with a biasing spring 138.

[0040] Particularly, the control piston 136 has a control piston cavity 140 as shown in Figure 6.

If fluid is provided to the control piston cavity 140, the control piston 136 extends, pushing the swashplate 120 against the biasing spring 138 and reducing the angle of the swashplate 120 (e.g., causes the swashplate 120 to move toward a vertical position perpendicular to the input shaft 114). On the other hand, if fluid in the control piston cavity 140 is drained, the biasing spring 138 pushes the control piston 136 back (causes the control piston 136 to retract), causing the angle of the swashplate 120 to increase relative to the input shaft 114.

[0041] The angle of the swashplate 120 determines respective strokes of the pistons of the rotating group 122, and thus determines the fluid flow rate discharged from the pump 118. If the angle of the swashplate 120 relative to the input shaft 114 is 90 degrees (e.g., the swashplate 120 is vertical), the pump 118 does not discharge fluid. However, when the swashplate 120 is actuated to a particular angle, the pistons of the rotating group 122 reciprocate within the cylinder block 128, thereby withdrawing fluid from a fluid reservoir coupled to the inlet port 110 and discharging fluid through the outlet port 112 of the pump 118.

[0042] The pump 118 further includes a valve plate 142. The valve plate 142 is configured as a disk having openings or holes that operate as inlet or low pressure holes fluidly coupled to the inlet port 110 of the pump 118. The inlet port 110 can be fluidly coupled to the fluid reservoir as mentioned above. The valve plate 142 also has openings or holes operating as an outlet or high pressure openings fluidly coupled to the outlet port 112 of the pump 118.

[0043] Figure 7 illustrates a cross-sectional view of the pump assembly 100, according to an example implementation. The cross-sectional plane of Figure 7 is labelled in Figure 5 and passes through the port block 104.

[0044] The port block 104 has a plurality of grooves, openings, or holes that are aligned with the respective openings of the valve plate 142. For example, the port block 104 can have holes 144, which can be aligned with the low pressure holes or inlet holes of the valve plate 142. The holes 144 are thus fluidly coupled to (in fluid communication with) the inlet port 110. [0045] The term “hole” is used generally herein to indicate a hollow place (e.g., cavity) in a solid body or surface, for example.

[0046] The port block 104 can also have an arcuate groove 146, which can be aligned with the high pressure openings of the valve plate 142. The arcuate groove 146 is thus fluidly coupled to the outlet port 112 through which high pressure fluid is discharged from the pump 118.

[0047] As shown in Figure 6, the piston 132 is disposed in the chamber 133 within the cylinder 130 at its most retracted position. This position can be referred to as the bottom dead center position. In this position of the piston 132, a volume of the chamber 133 within the cylinder 130 is maximum.

[0048] Referring to 6-7 together, as the cylinder block 128 rotates about a longitudinal axis of the input shaft 114, the piston 132 retracts on its way to the position shown in Figure 6, withdrawing fluid into the chamber 133 through the inlet port 110 (see Figures 2, 3-4), the holes 144 of the port block 104, and the corresponding low pressure holes in the valve plate 142. As the cylinder block 128 continues to rotate from the position shown in Figure 6, due to the angle of the swashplate 120, the piston 132 extends.

[0049] As the piston 132 extends, the volume of the chamber 133 is reduced, and the piston 132 compresses fluid in the chamber 133, causing fluid to be discharged from the chamber 133 through the high pressure openings of the valve plate 142, the arcuate groove 146 of the port block 104, and the outlet port 112 (see Figures 1, 3). When the piston 132 reaches its most extended position, which could be referred to as the top dead center position, the volume of the chamber 133 is a minimum volume. [0050] All the pistons of the rotating group 122 go through these retraction and extension cycles. Thus, as the input shaft 114 and the rotating group 122 rotate, the pistons reciprocate within their respective cylinders within the cylinder block 128, thereby alternating between withdrawing fluid through the inlet port 110 and pushing fluid through the outlet port 112, discharging fluid from the pump 118.

[0051] Referring to Figure 7, as mentioned above, the arcuate groove 146 formed in the port block 104 is in fluid communication with the outlet port 112 (high pressure fluid being discharged from the pump 118). The port block 104 further includes a first slanted channel 148 that is fluidly coupled, and branching from, the arcuate groove 146. The port block 104 also includes a second slanted channel 149a branching from the first slanted channel 148 and a third slanted channel 149b branching from the second slanted channel 149a. The third slanted channel 149b is fluidly coupled, and is configured to provide high pressure fluid, to the pressure control valve 116 via the housing 102.

[0052] Figure 8 illustrates a cross-sectional view of the pump assembly 100, and Figure 9 illustrates another cross-sectional view of the pump assembly 100, according to an example implementation. The cross-sectional plane of Figure 8 is labelled in Figure 4, and the cross- sectional plane of Figure 9 is labelled in Figure 3.

[0053] As shown in Figure 8, the second slanted channel 149 is fluidly coupled to a fluid passage 150 (e.g., a drilled fluid passage) formed in the housing 102. Referring to Figures 8-9 together, the fluid passage 150 is in turn fluidly coupled to a fluid passage 151 (e g., a drilled fluid passage) that provides fluid to the pressure control valve 116.

[0054] Figure 10 illustrates a cross-sectional view of the pressure control valve 116, according to an example implementation. The cross-sectional plane of Figure 10 is labelled in Figure 3. [0055] As shown in Figure 10, the pressure control valve 116 has a valve housing 152 that is mounted (e.g., via fasteners) to the housing 102. In other configurations, however, the valve housing 152 may be integral with the housing 102.

[0056] The valve housing 152 includes or defines several channels or cavities including pump outlet fluid cavity 154, control piston cavity 156, and drain cavity 158. The pump outlet fluid cavity 154 is fluidly coupled to the fluid passage 151 (see Figure 9), which receives high pressure fluid from the outlet port 112 of the pump 118 as described above. The control piston cavity 156 is fluidly coupled to the control piston cavity 140 of the control piston 136 (see Figure 6). The drain cavity 158 is fluidly coupled to the case drain port 108 of the pump assembly 100, and may thus fluidly coupled to a low pressure fluid reservoir (e.g., the fluid reservoir 109 in Figure 12).

[0057] The pressure control valve 116 includes a spool 160 mounted, and axially movable, within a longitudinal bore formed within the valve housing 152. The longitudinal bore in which is the spool 160 is disposed intercepts the pump outlet fluid cavity 154, the control piston cavity 156, and the drain cavity 158. The spool 160 has a spool body varying in diameter along a length of the spool body, thereby forming a plurality of lands, such as land 162 having enlarged diameters, to control fluid flow or communication between the pump outlet fluid cavity 154, the control piston cavity 156, and the drain cavity 158.

[0058] The valve housing 152 has a spring cavity in which one or more valve springs 164 is disposed. The one or more valve springs 164 applies a biasing force on the spool 160 to bias the spool 160 toward the position shown in Figure 10. In this position, the land 162 blocks fluid communication between the pump outlet fluid cavity 154 and the control piston cavity 156, while allowing fluid communication between the control piston cavity 156 and the drain cavity 158. In this state, the control piston cavity 140 is drained to the case drain port 108 (and thus the fluid reservoir), and the biasing spring 138 (see Figure 6) pushes the swashplate 120 and the control piston 136 such that the swashplate 120 is disposed at an angle relative to the input shaft 114 of the pump 118, allowing the pump 118 to discharge flow through the outlet port 112. Thus, a position of the spool 160 controls a respective position of the control piston 136 and the angle of the swashplate 120.

[0059] A fluid signal having pressure level of the fluid discharged from the pump 118 is communicated through the second slanted channel 149a, the third slanted channel 149b, and the fluid passages 150, 151 to the pump outlet fluid cavity 154 as described above. If pressure level of such fluid signal reaches a threshold pressure level that overcomes the biasing force of the one or more valve springs 164, the spool 160 can move (to the right in Figure 8) against the one or more valve springs 164.

[0060] As the spool 160 moves to the extent that the land 162 no longer blocks fluid communication between the pump outlet fluid cavity 154 and the control piston cavity 156, the control piston cavity 140 of the control piston 136 receives pressurized fluid, causing the control piston 136 to push the swashplate 120 against the biasing spring 138, thereby limiting fluid flow and reducing pressure level of fluid supplied through the outlet port 112. As such, the spool 160 modulates fluid communication between the pump outlet fluid cavity 154, the control piston cavity 156, and the drain cavity 158 to control the pressure level of fluid supplied through the outlet port 112 of the pump 118 such that the pressure level does not exceed a threshold pressure level that is based on the spring rate and preload of the one or more valve springs 164.

[0061] With this configuration, the pressure control valve 116 is configured as a pressure limiting control or pressure cut-off device that regulates the pressure level of fluid discharged through the outlet port 112. Particularly, the pressure control valve 116 senses the pressure level of the fluid being discharged from the outlet port 112, and adjusts the flow rate to maintain a consistent pressure level, even when demand for fluid flow changes.

[0062] Notably, the fluid passages (the first slanted channel 148, the second slanted channel 149a, the third slanted channel 149b, and the fluid passages 150, 151) that communicate fluid to the pressure control valve 116 exhibit natural (resonant) frequencies that are characteristic of their lengths and diameters. Thus, as the rotating group 122 of the pump assembly 100 rotates, fluid pressure ripples may occur within the fluid passages at the resonant frequencies. Due to the physical characteristics of these fluid passages, their natural frequencies and resulting high amplitude pressure ripples within the fluid passages can be in the range of 1000 - 2000 Hz.

[0063] The pressure ripples in that frequency range can cause components within the pump assembly 100 to respond and oscillate. For example, the spool 160 of the pressure control valve 116 may oscillate due to such ripples, causing a high frequency whistling sound due to the erratic flow across the spool 160. Resonant ripples can also cause damage to internal components of the pump (e.g., cause wear of spools and valve bodies, elastomeric seals, etc.). Such erratic flow, pressure ripples, whistling, and internal component damage are undesirable. To avoid such resonant pressure ripples, the pump assembly 100 includes an attenuator configuration that dampens the pressure ripples, and thereby prevents spool oscillations.

[0064] Figure 11 illustrates an enlarged view of the cross-section depicted in Figure 8, and Figure 12 illustrates a schematic of a hydraulic system 165 including the pump assembly 100, according to an example implementation. Referring to Figures 8, 11-12 together, the attenuator configuration includes (i) an attenuator chamber 166 (e.g., a volume) formed within the housing 102, and (ii) an attenuator orifice 168 that fluidly couples the fluid passage 150 to the attenuator chamber 166. As described above, the fluid passage 150 receives, via the third slanted channel 149b, fluid signal from the fluid being discharged from the pump 118 through the outlet port 112).

[0065] In the example implementation shown in Figures 8, 11-12, the attenuator orifice 168 is formed immediately adjacent (e.g., within 1-2 millimeter) the fluid passage 151 connected to the pressure control valve 116. This feature renders the configuration compact and may enhance dampening of the pressure ripples provided to the pressure control valve 116.

[0066] Notably, the size of the attenuator orifice 168 affects the ability of the attenuator configuration to dampen pressure ripples and whistling. In the configuration disclosed herein, the attenuator orifice 168 is a straight hole drilled in the housing 102. The term “straight hole” indicates that the orifice or hole does not include other rods or the like therethrough, and thus the orifice is not annular.

[0067] Further, the diameter of the attenuator orifice 168 is substantially smaller than (e.g., less than 25% of) the respective diameter of the adjacent fluid passages (e.g., the fluid passages 150, 151). For example, if the diameter of the fluid passage 150 is 4.2 millimeter (mm), the diameter of the attenuator orifice 168 may be equal to or less than 1 mm (e.g., 0.8 mm) such that the diameter of the attenuator orifice 168 is less than 25% (e.g., about 20%) of the diameter of the fluid passage 150. The term “about” is used to indicate that the diameter is within a threshold percentage (e.g., plus or minus 2% of 20%).

[0068] The attenuator chamber 166 is constructed as a blind hole drilled in the housing 102, for example. This simplifies manufacturing of the pump assembly 100, reducing cost. Further, forming the attenuator chamber 166 and the attenuator orifice 168 to provide the attenuator configuration does not increase the size of the pump assembly 100 or the housing 102. No external components are added to the pump assembly 100 to form the attenuator configuration.

[0069] Notably, the attenuator chamber 166 does not have connections to other internal passages besides the attenuator orifice 168.

[0070] It may be desirable to increase the volume of the attenuator chamber 166 to enhance performance of the attenuator. For example, the attenuator chamber 166 can have a diameter of 9.5 mm and a length of 41 mm.

[0071] In examples, after the attenuator chamber 166 is formed, e.g., by drilling a hole in the housing 102, the hole can be used as a diagnostic port 170 that allows a pressure sensor (e.g., pressure gauge) to be mounted to the housing 102 to have access to the attenuator chamber 166. The pressure sensor can thus provide sensor information to a controller, for example, indicating pressure levels and ripple frequencies.

[0072] Although the attenuator configuration (e.g., the attenuator chamber 166 and the attenuator orifice 168) in the example implementation shown in the figures is disposed in the housing 102, other configurations are possible. For example, the attenuator chamber 166 and the attenuator orifice 168 can be formed in the valve housing 152. In another example, the attenuator chamber 166 and the attenuator orifice 168 can be formed in the port block 104.

[0073] Figure 13 is a graph 200 depicting simulation results showing pressure amplitude versus frequency with and without the attenuator configuration, according to an example implementation. The x-axis represents frequency in Hertz (Hz), while the y-axis represents the pressure amplitude in various fluid passages (e.g., the slanted channels 148, 149a, 149b, the fluid passages 150, 151, the pump outlet fluid cavity 154) in bar. [0074] Line 202 represents pressure amplitude when the attenuator configuration is not used. As shown, pressure oscillates with an amplitude as high as about 31 bar at a frequency between 1750 and 2000 Hz. Line 204 represents the effect of adding the attenuator configuration to the pump assembly 100, which causes the peak pressure magnitude to be reduced or attenuated substantially to about 1 bar, thereby protecting the pump assembly 100 from the consequences of pressure ripple.

[0075] Figure 14 is a graph 300 depicting simulation results showing pressure amplitude versus time with and without the attenuator configuration, according to an example implementation. The x-axis represents time in seconds (s), while the y-axis represents the pressure amplitude in bar.

[0076] Line 302 represents the amplitude of pressure when the attenuator configuration is not used. As shown, a sustained ripple or oscillation occurs, which can have several negative consequences as described above. The period of the oscillations amount to approximately 0.56 millisecond, or 1785 Hz. Line 304 represents the effect of adding the attenuator configuration to the pump assembly 100, which causes the pressure oscillation to be suppressed or dampened substantially. This way, negative consequences of a resonant ripple in the fluid discharged by the pump 118 are substantially alleviated.

[0077] Figure 15 is a flowchart of a method 400 of operating the pump assembly 100 or the hydraulic system 165, according to an example implementation. The method 400 may include one or more operations, or actions as illustrated by one or more of blocks 402-406. Although the blocks are illustrated in a sequential order, these blocks may in some instances be performed in parallel, and/or in a different order than those described herein. Also, the various blocks may be combined into fewer blocks, divided into additional blocks, and/or removed based upon the desired implementation.

[0078] At block 402, the method 400 includes operating the pump 118 within the housing 102 of the pump assembly 100, wherein the pump assembly 100 comprises the port block 104 coupled to the housing 102 and having the inlet port 110 and the outlet port 112, and wherein operating the pump 118 comprises drawing fluid from the inlet port 110 and discharging fluid through the outlet port 112.

[0079] At block 404, the method 400 includes communicating a fluid signal, via one or more fluid passages (e.g., fluid passages in the cylinder block 128, the valve plate 142, the arcuate groove 146, the first slanted channel 148, the second slanted channel 149a, the third slanted channel 149b, the fluid passages 150, 151, etc.) from fluid being discharged from the pump to the pressure control valve 116 that regulates pressure level of fluid discharged by the pump 118 through the outlet port 112.

[0080] At block 406, the method 400 includes dampening the fluid signal via the attenuator orifice 168 that fluidly couples a fluid passage (e.g., the fluid passage 150, 151) of the one or more fluid passages to the attenuator chamber 166.

[0081] The method 400 can further include any of the steps or operations described above with respect to Figures 1-14.

[0082] The detailed description above describes various features and operations of the disclosed systems with reference to the accompanying figures. The illustrative implementations described herein are not meant to be limiting. Certain aspects of the disclosed systems can be arranged and combined in a wide variety of different configurations, all of which are contemplated herein. [0083] Further, unless context suggests otherwise, the features illustrated in each of the figures may be used in combination with one another. Thus, the figures should be generally viewed as component aspects of one or more overall implementations, with the understanding that not all illustrated features are necessary for each implementation.

[0084] Additionally, any enumeration of elements, blocks, or steps in this specification or the claims is for purposes of clarity. Thus, such enumeration should not be interpreted to require or imply that these elements, blocks, or steps adhere to a particular arrangement or are carried out in a particular order.

[0085] Further, devices or systems may be used or configured to perform actuators presented in the figures. In some instances, components of the devices and/or systems may be configured to perform the actuators such that the components are actually configured and structured (with hardware and/or software) to enable such performance. In other examples, components of the devices and/or systems may be arranged to be adapted to, capable of, or suited for performing the actuators, such as when operated in a specific manner.

[0086] By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those with skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

[0087] The arrangements described herein are for purposes of example only. As such, those skilled in the art will appreciate that other arrangements and other elements (e.g., machines, interfaces, operations, orders, and groupings of operations, etc.) can be used instead, and some elements may be omitted altogether according to the desired results. Further, many of the elements that are described are functional entities that may be implemented as discrete or distributed components or in conjunction with other components, in any suitable combination and location.

[0088] While various aspects and implementations have been disclosed herein, other aspects and implementations will be apparent to those skilled in the art. The various aspects and implementations disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope being indicated by the following claims, along with the full scope of equivalents to which such claims are entitled. Also, the terminology used herein is for the purpose of describing particular implementations only, and is not intended to be limiting.

[0089] Embodiments of the present disclosure can thus relate to one of the enumerated example embodiments (EEEs) listed below.

[0090] EEE 1 is a pump assembly comprising: a housing; a port block coupled to the housing and having an inlet port and an outlet port; a pump disposed within the housing, wherein the pump draws fluid through the inlet port and discharges fluid through the outlet port; a pressure control valve that regulates pressure level of fluid discharged by the pump through the outlet port; one or more fluid passages that communicate a fluid signal from fluid discharged by the pump to the pressure control valve; an attenuator chamber; and an attenuator orifice that fluidly couples the one or more fluid passages to the attenuator chamber.

[0091] EEE 2 is the pump assembly of EEE 1, wherein the one or more fluid passages comprise: at least one channel formed in the port block; and at least one fluid passage formed in the housing, wherein the attenuator orifice fluidly couples the at least one fluid passage to the attenuator chamber. [0092] EEE 3 is the pump assembly of EEE 2, wherein the at least one channel formed in the port block is a slanted channel.

[0093] EEE 4 is the pump assembly of any of EEEs 2-3, wherein the port block includes an arcuate groove through which fluid discharged from the pump is provided to the outlet port, and wherein the at least one channel formed in the port block fluidly couples the arcuate groove to the at least one fluid passage formed in the housing.

[0094] EEE 5 is the pump assembly of any of EEEs 1-4, wherein the pump comprises: a rotating group having a cylinder block and a plurality of pistons disposed in respective cylinders formed in the cylinder block; a swashplate contacting the plurality of pistons such that an angle of the swashplate determines respective strokes of the plurality of pistons and a fluid flow rate discharged from the pump; and a control piston coupled to the swashplate such that the control piston determines the angle of the swashplate.

[0095] EEE 6 is the pump assembly of EEE 5, further comprising: a drain port configured to provide internal leakage fluid of the pump to a fluid reservoir, wherein the pressure control valve comprises: a spool; and a plurality of cavities comprising: (i) a pump outlet fluid cavity that receives fluid from the one or more fluid passages, (ii) a control piston cavity that is in fluid communication with the control piston, and a drain cavity that is fluidly coupled to the drain port, such that a position of the spool controls fluid communication between the plurality of cavities to set a respective position of the control piston and the swashplate, and wherein the attenuator orifice fluidly couples the one or more fluid passages, which provide fluid to the pump outlet fluid cavity, to the attenuator chamber.

[0096] EEE7 is the pump assembly of any of EEEs 1-6, wherein the attenuator orifice is a straight hole having a diameter that is equal to or less than 1 millimeter. [0097] EEE 8 is the pump assembly of any of EEEs 1-7, wherein the attenuator orifice is formed immediately adjacent a fluid passage, of the one or more fluid passages, connected to the pressure control valve.

[0098] EEE 9 is the pump assembly of any of EEEs 1-8, wherein the attenuator orifice has a diameter that is less 25% of a respective diameter of an adjacent fluid passage of the one or more fluid passages.

[0099] EEE 10 is the pump assembly of EEE 9, wherein the diameter of the attenuator orifice is about 20% of the respective diameter of the adjacent fluid passage of the one or more fluid passages.

[00100] EEE 11 is the pump assembly of any of EEEs 1-10, wherein the attenuator chamber is formed as a blind hole.

[00101] EEE 12 is the pump assembly of EEE 11, wherein the blind hole is connected only to the attenuator orifice.

[00102] EEE 13 is the pump assembly of any of EEEs 1-12, wherein the attenuator orifice and the attenuator chamber are formed in the housing.

[00103] EEE 14 is the pump assembly of any of EEEs 1-12, wherein the attenuator orifice and the attenuator chamber are formed in the port block.

[00104] EEE 15 is the pump assembly of any of EEEs 1-12, wherein the pressure control valve comprises a valve housing mounted to the housing, and wherein the attenuator orifice and the attenuator chamber are formed in the valve housing.

[00105] EEE 16 is the pump assembly of any of EEEs 1-15, wherein the pressure control valve is mounted to the housing or the port block. [00106] EEE 17 is a hydraulic system comprising: a fluid reservoir that contains low pressure fluid; a fluid consumer device; and the pump assembly of any of EEEs 1-16. For example, the pump assembly comprises: a housing, a port block coupled to the housing and having (i) an inlet port that is fluidly coupled to the fluid reservoir, and (ii) an outlet port that is fluidly coupled to the fluid consumer device, a pump disposed within the housing, wherein the pump draws fluid through the inlet port and discharges fluid through the outlet port, a pressure control valve that regulates pressure level of fluid discharged by the pump through the outlet port, one or more fluid passages that communicate a fluid signal from fluid discharged by the pump to the pressure control valve, an attenuator chamber, and an attenuator orifice that fluidly couples the one or more fluid passages to the attenuator chamber.

[00107] EEE 18 is the hydraulic system of EEE 17, wherein the one or more fluid passages comprise: at least one channel formed in the port block; and at least one fluid passage formed in the housing, wherein the attenuator orifice fluidly couples the at least one fluid passage to the attenuator chamber.

[00108] EEE 19 is a method of operating the pump assembly of any of EEEs 1-16 or the hydraulic system of any of EEEs 17-18. For example, the method comprises: operating a pump within a housing of a pump assembly, wherein the pump assembly comprises a port block coupled to the housing and having an inlet port and an outlet port, and wherein operating the pump comprises drawing fluid from the inlet port and discharging fluid through the outlet port; communicating a fluid signal, via one or more fluid passages, from fluid being discharged from the pump to a pressure control valve that regulates pressure level of fluid discharged by the pump through the outlet port; and dampening the fluid signal via an attenuator orifice that fluidly couples a fluid passage of the one or more fluid passages to an attenuator chamber. [00109] EEE 20 is the method of EEE 19, wherein communicating the fluid signal via the one or more fluid passages comprises: communicating the fluid signal via at least one channel formed in the port block and at least one fluid passage formed in the housing, wherein the attenuator orifice fluidly couples the at least one fluid passage to the attenuator chamber.

Claims

CLAIMS What is claimed is:

1. A pump assembly comprising: a housing; a port block coupled to the housing and having an inlet port and an outlet port; a pump disposed within the housing, wherein the pump draws fluid through the inlet port and discharges fluid through the outlet port; a pressure control valve that regulates pressure level of fluid discharged by the pump through the outlet port; one or more fluid passages that communicate a fluid signal from fluid discharged by the pump to the pressure control valve; an attenuator chamber; and an attenuator orifice that fluidly couples the one or more fluid passages to the attenuator chamber.

2. The pump assembly of claim 1, wherein the one or more fluid passages comprise: at least one channel formed in the port block; and at least one fluid passage formed in the housing, wherein the attenuator orifice fluidly couples the at least one fluid passage to the attenuator chamber.

3. The pump assembly of claim 2, wherein the at least one channel formed in the port block is a slanted channel.

4. The pump assembly of claim 2, wherein the port block includes an arcuate groove through which fluid discharged from the pump is provided to the outlet port, and wherein the at least one channel formed in the port block fluidly couples the arcuate groove to the at least one fluid passage formed in the housing.

5. The pump assembly of claim 1, wherein the pump comprises: a rotating group having a cylinder block and a plurality of pistons disposed in respective cylinders formed in the cylinder block; a swashplate contacting the plurality of pistons such that an angle of the swashplate determines respective strokes of the plurality of pistons and a fluid flow rate discharged from the pump; and a control piston coupled to the swashplate such that the control piston determines the angle of the swashplate.

6. The pump assembly of claim 5, further comprising: a drain port configured to provide internal leakage fluid of the pump to a fluid reservoir, wherein the pressure control valve comprises: a spool; and a plurality of cavities comprising: (i) a pump outlet fluid cavity that receives fluid from the one or more fluid passages, (ii) a control piston cavity that is in fluid communication with the control piston, and a drain cavity that is fluidly coupled to the drain port, such that a position of the spool controls fluid communication between the plurality of cavities to set a respective position of the control piston and the swashplate, and wherein the attenuator orifice fluidly couples the one or more fluid passages, which provide fluid to the pump outlet fluid cavity, to the attenuator chamber.

7. The pump assembly of claim 1, wherein the attenuator orifice is a straight hole having a diameter that is equal to or less than 1 millimeter.

8. The pump assembly of claim 1, wherein the attenuator orifice is formed immediately adjacent a fluid passage, of the one or more fluid passages, connected to the pressure control valve.

9. The pump assembly of claim 1, wherein the attenuator orifice has a diameter that is less 25% of a respective diameter of an adjacent fluid passage of the one or more fluid passages.

10. The pump assembly of claim 9, wherein the diameter of the attenuator orifice is about 20% of the respective diameter of the adjacent fluid passage of the one or more fluid passages.

11. The pump assembly of claim 1, wherein the attenuator chamber is formed as a blind hole.

12. The pump assembly of claim 11, wherein the blind hole is connected only to the attenuator orifice.

13. The pump assembly of claim 1, wherein the attenuator orifice and the attenuator chamber are formed in the housing.

14. The pump assembly of claim 1, wherein the attenuator orifice and the attenuator chamber are formed in the port block.

15. The pump assembly of claim 1, wherein the pressure control valve comprises a valve housing mounted to the housing, and wherein the attenuator orifice and the attenuator chamber are formed in the valve housing.

16. The pump assembly of claim 1, wherein the pressure control valve is mounted to the housing or the port block.

17. A hydraulic system comprising: a fluid reservoir that contains low pressure fluid; a fluid consumer device; and a pump assembly comprising: a housing, a port block coupled to the housing and having (i) an inlet port that is fluidly coupled to the fluid reservoir, and (ii) an outlet port that is fluidly coupled to the fluid consumer device, a pump disposed within the housing, wherein the pump draws fluid through the inlet port and discharges fluid through the outlet port, a pressure control valve that regulates pressure level of fluid discharged by the pump through the outlet port, one or more fluid passages that communicate a fluid signal from fluid discharged by the pump to the pressure control valve, an attenuator chamber, and an attenuator orifice that fluidly couples the one or more fluid passages to the attenuator chamber.

18. The hydraulic system of claim 17, wherein the one or more fluid passages comprise: at least one channel formed in the port block; and at least one fluid passage formed in the housing, wherein the attenuator orifice fluidly couples the at least one fluid passage to the attenuator chamber.

19. A method comprising: operating a pump within a housing of a pump assembly, wherein the pump assembly comprises a port block coupled to the housing and having an inlet port and an outlet port, and wherein operating the pump comprises drawing fluid from the inlet port and discharging fluid through the outlet port; communicating a fluid signal, via one or more fluid passages, from fluid being discharged from the pump to a pressure control valve that regulates pressure level of fluid discharged by the pump through the outlet port; and dampening the fluid signal via an attenuator orifice that fluidly couples a fluid passage of the one or more fluid passages to an attenuator chamber.

20. The method of claim 19, wherein communicating the fluid signal via the one or more fluid passages comprises: communicating the fluid signal via at least one channel formed in the port block and at least one fluid passage formed in the housing, wherein the attenuator orifice fluidly couples the at least one fluid passage to the attenuator chamber.