Abstract: A hydraulic pump or motor includes a mounting flange that is disposed at the first end of the housing. The mounting flange defines a pair of bolt receiving slots that are disposed along the X-axis on either side of the shaft. The pair of bolt receiving slots each define a radius center that are spaced away from each other a X dimension, and a pilot projection extends longitudinally away from the mounting flange, defining a pilot projection diameter. A ratio of the X dimension to the pilot projection diameter ranges from 1.1 to 1.5.

Abstract: A uniaxial eccentric screw pump includes: a rotor 1 including a shaft body of a male screw type; a stator 2 having a through hole 2a of a female screw type through which the rotor 1 is inserted; a casing 3 connected to one end side of the stator 2; an end stud 4 connected, to the other end side of the stator 2; and a position adjusting member 5 that adjusts a relative position of the stator 2 with respect to the rotor 1 in an axial direction.

Abstract: A stator for use in a positive displacement motor or a progressing cavity pump. The stator comprises an elastomer mix preferably including rubber and a fiber reinforcement. The fiber reinforcement includes a plurality of fibers. The elastomer mix is formed into a stator via an injection molding process. The injection molding process includes a shear flow step in which shear flow is induced in the elastomer mix while the elastomer mix is in an uncured state. The shear flow modifies the orientation of the fibers into an advantageous modified fiber orientation. Shear flow is induced preferably via differential rotation of injection mold assembly elements during the injection molding process. Methods of manufacturing the stator are also disclosed.

Abstract: A fluid pump includes a rotor which is centered about an axis, the rotor having a rotor central chamber and a plurality of vane slots. A stator has a recess therein within which the rotor is located, the recess having a recess peripheral surface which is eccentric to the axis. Each vane slot includes a vane therein such that the vanes define a plurality of pumping chambers which expand and contract based on rotational position the rotor relative to the stator. A positioning ring is located within the rotor central chamber such that the positioning ring engages each vane and such that the positioning ring urges each vane into contact with the recess peripheral surface. The positioning ring is radially aligned with a midpoint of each vane.

Abstract: A vane pump includes: a casing forming a pump chamber therein; a rotor arranged inside the casing to rotate eccentrically with respect to the casing; and a plurality of vanes configured to rotate with the rotor and slide on an inner side surface of the casing. At least one of Formula (1): l?(b/a)×k and Formula (2): l?(c/a)×j is satisfied, where “a” represents a height of the pump chamber, “b” represents a height of the rotor, “c” represents a height of the vane in a rotation axis direction of the rotor, and where “l” represents a linear expansion coefficient of the casing in the rotation axis direction, “k” represents a linear expansion coefficient of the rotor in the rotation axis direction, and “j” represents a linear expansion coefficient of the vane in the rotation axis direction.

Abstract: A downhole drilling motor includes a motor housing having an inner bore and an outer surface. A power section includes a stator elastomer at least partially disposed within the inner bore of the motor housing. A bearing section includes an upper bearing at least partially disposed within the inner bore of the motor housing. The motor housing further includes an opening extending from the inner bore to the outer surface to provide a bypass fluid path for a fluid in the inner bore. The opening is disposed on the motor housing between a lower end of the stator elastomer and an upper end of the upper bearing. The bypass fluid path allows the downhole drilling motor to accommodate a higher flow rate of a fluid through the stator elastomer of the power section than through the upper bearing of the bearing section.

Abstract: A method of making a stator includes positioning an inner tubular member having an inner surface within an outer tubular member, installing a rigid mandrel within the inner tubular member, and applying a compressive force to at least one of the inner tubular member and the outer tubular member.

Abstract: The invention relates to a rotary piston pump for one-time use made of plastic for screwing onto a fastening nozzle on a tubular bag, having two rotors (10), which are coupled to each other via gear wheels (11) and which can be driven in opposition and which are mounted in a pump housing (5), which has suction nozzles (6) and outlet nozzles (7), wherein each rotor (10) has a rotor shaft (12), the rotor shaft ends (15) thereof being mounted in the walls (8, 4) of the pump housing (5), and the gear wheels are integrally molded to the rotor shafts, and wherein each rotor (10) has two rotor wing walls (13) arranged diametrically on the rotor shaft (12) which flare continuously outward and to each of the peripheral ends of which a partially cylindrical rotor wing shoe (14) is molded, wherein the rotor wing shoes (14) contact the cylindrical inside wall regions of the pump housing (5), on one side, and the rotor wing shafts (13) of the adjacent rotor (10) on the other, in a sliding and sealing matter, wherein seals

Abstract: A fluid gear pump gear arranged to rotate about a first axis includes a concentrically disposed first hub portion and a plurality of first teeth radially projecting and circumferentially spaced about the first hub portion, the first hub portion and the first teeth being formed of a ceramic material. The gear also includes a first shaft on which the first hub portion is carried.

Abstract: Suction muffler (1) for a hermetic refrigeration compressor (2), the suction muffler (1) comprising an inlet (3), so that refrigerant can flow into the suction muffler (1), and an outlet (4), so that refrigerant can flow out from the suction muffler (1), the suction muffler (1) further comprising two damping chambers (5, 6) for sound damping, where the two damping chambers (5, 6) each has a floor (8, 9) and where a wall element (11) is provided, in order to separate the two damping chambers (5, 6) from each other for the refrigerant in the region of their floors (8, 9).

Abstract: A rotor assembly has a vane which engages an eccentric cam block using an insert. The insert is removably attached to the vane. The vane is captured within a transverse slot in the rotor and executes reciprocal motion transversely to the axis of rotation of the rotor as the rotor rotates.

Abstract: A delivery element for a rotary pump is proposed which is formed in one part from a metallic material, wherein the delivery element includes at least one first surface and at least one second surface which differ from each other, at least in regions, in at least one material property. A method for manufacturing a delivery element in accordance with the invention, a rotary pump including at least one delivery element in accordance with the invention, and the use of a delivery element in accordance with the invention in a rotary pump is also proposed.

Abstract: A lightweight gear pump easy to manufacture, having a reduced manufacturing cost, while giving sufficient performances. It consists of: A gear, three metal plates, placed on each other, an intermediate plate of which including an eight-shaped cavity adapted to house the gear, and two peripheral plates having the function of enclosing the gear in the cavity, a circuit for fluid supply to the gear, centering means to align the three plates above each other, the three metal plates being provided with centering holes in the axial direction, adapted to receive the centering means, the device according to the invention is particularly intended for liquid transfer applications for automobiles or heavy trucks.

Abstract: A method of treating, tuning, assembling, and/or overhauling a twin rotor device (200, 1200) includes applying a coating material (102) on an internal set of working surfaces (218, 222, 224, 226, 228, 1218, 1222, 1224, 1226, 1228) of the twin rotor device when at least partially assembled. The coating may be factory or field applied to a new or used twin rotor device. The working surfaces may be uncoated or previously coated and may be built-up as the coating material forms a coating (206, 1206) on at least some of the working surfaces. Manufacturing variations of a pair of rotors (220, 1220) and a housing (210, 1210) may be compensated by the coating. One or more performance characteristics of the twin rotor device may be improved by the coating, and variation between a series of twin rotor device may be reduced or substantially eliminated. The coating may reduce internal leakage and increase volumetric efficiency of the twin rotor device.

Abstract: Embodiments of the present invention are generally related to a method and apparatus for subterranean wellbores and in particular, to a method and apparatus for rotating a subsurface tubular string, such as a casing section, without rotation at the surface. More specifically, a casing section of a wellbore may be rotated to provide a cement seal with increased strength and reliability. In one embodiment, a downhole tool and rotation assembly is disclosed which imparts a torsional force to a predetermined casing section when a fluid is flowed through the downhole tool and rotation assembly.

Abstract: An eccentric screw pump, comprising a rotor that extends along a longitudinal axis of the rotor from a drive end to a free end, a stator housing with an internal cavity that extends along the longitudinal axis from a stator inlet opening to a stator outlet opening and that is designed to accommodate the rotor, a drive motor with a drive shaft that is coupled with the rotor to transmit a torque, a first cardan joint which is placed within the transmission of the torque between the drive shaft and the rotor, and a stator outlet flange that is arranged in flow direction behind the rotor. The stator outlet flange comprises a flange connection plane that is oriented non-vertically to the longitudinal axis.

Abstract: The present disclosure relates to a mixing pump (10) for combining two or more substances. More specifically, the mixing pump (10) is adapted to combine controlled amounts of those substances so as to produce a mixture containing predetermined proportions of those substances. The mixing pump includes a chamber (23) lying in fluid communication with a first substance inlet (50), a second substance inlet (51) and a mixture outlet (52). The mixing pump (10) also includes a pumping member disposed in the chamber (23) and adapted to draw first and second substances from the first and second substance inlets (50,51) and to expel a mixture of those substances through the mixture outlet (52).

Abstract: Scroll members for scroll compressors made from one or more near-net shaped powder metal processes, either wholly or partially fabricated together from sections. In certain variations, the involute scroll portion of the scroll member has a modified terminal end region. The terminal end region may include an as-sintered coupling feature comprising a tip component that forms a contact surface for contacting an opposing scroll member during compressor operation. The tip component can be a tip seal or a tip cap received by the as-sintered coupling feature. The tip cap may be sinter-bonded or otherwise coupled to the terminal end region. In other variations, a terminal end region may comprise a second material including a tribological material that forms a contact surface. Methods of making such scroll members for scroll compressors are also provided.

Abstract: Disclosed herein is a vane rotary compressor in which a fluid such as a refrigerant is compressed while a volume of a compression chamber is reduced during rotation of a rotor. There is provided a vane rotary compressor capable of preventing a delay of rotation operation of a vane by respectively forming oil films on both sides of a hinge portion of the vane in a rotation direction thereof and smoothly sliding the hinge portion.

Abstract: A rotary compressor includes: a compressing unit that includes an annular cylinder, an end plate, an annular piston which is fit in an eccentric portion of a rotation shaft, and a vane which protrudes from the inside of a vane groove of the cylinder to the inside of an operation chamber, comes into contact with the annular piston, and partitions the operation chamber into an inlet chamber and a compression chamber. The vane is formed of steel and has a diamond-like carbon layer formed on a sliding surface with respect to the annular piston. The annular piston is formed of Ni—Cr—Mo cast iron to which 0.15 wt % to 0.45 wt % of phosphorus is added, or is formed of cast iron or steel and has an iron nitride layer formed on an outer circumferential surface thereof.

Abstract: A scroll member includes a base having a panel and a spiral blade provided to extend from the panel toward another scroll member, resin layer L1 formed on the base, and a plurality of grooves C formed on a surface of the resin layer. The plurality of grooves C are formed on the surface of resin layer L1. A cross-section of each groove C has a shape similar to a U-shape or a semicircle in which the width decreases toward the deeper position and the rate of change in width increases toward the bottom. Grooves C are formed by moving an edge of a cutting tool along the original surface of the resin layer, which is originally formed on base L0 by application or the like.

Abstract: In one embodiment, a compression mechanism unit of a rotary compressor includes a cylinder includes a cylinder chamber, a roller in the chamber, first and second vanes which come into contact with the roller and partition the chamber into a compression side and an absorption side, and a bias member which biases the vanes. On both end sides of a posterior end portion of the first vane, first vane side attachment portions having an equal dimension in the axial direction are provided. On both end sides of the second vane along the axial direction of the axis, second vane side attachment portions having an equal dimension in the axial direction are provided. The vanes are attached to the bias member via the attachment portions.

Abstract: An orbiting scroll is fixed on a rotating table and rotated about a spiral center. A spray nozzle is positioned in the spiral center or at an outside end of the orbiting scroll and caused to discharge a coating toward a side face of a wrap portion. The spray nozzle is moved along a straight line in a radial direction while discharging the coating. When a spraying start position is set as the spiral center, a rotation angle speed of the orbiting scroll is gradually reduced in accordance with the movement of the spray nozzle. When the spraying start point is set as the outside end, the rotation angle speed of the orbiting scroll is gradually increased in accordance with the movement of the spray nozzle. As a result, the coating can be applied to the wrap portion side face evenly.

Abstract: A motor assembly for a pneumatic tool includes: a motor cylinder coaxially secured in a tubular inner housing, which is coaxially secured in a tubular outer housing and has an inlet passage defining a longitudinal axis, including a valve seat, and defining forward and reverse passages that communicate with a motor chamber and extend through the valve seat, and an exhaust port that communicates with the motor chamber, and a throttle passage defined between the inner and outer housings; a motor rotor supported within the motor chamber and rotatable in a forward or reverse direction; and a rotary valve coaxially disposed in the inner housing, supported by the valve seat, and rotatable about the longitudinal axis between forward and reverse positions.

Abstract: A rotary vane pump includes a housing that encloses an air chamber. An intake aperture extends to the air chamber. A check valve couples with the intake aperture and includes a stop having first and second sides. A helical spring engages the first side and biases the second side against a valve seat. A porous body is disposed between the helical spring and the air chamber for preventing fluid backflow.

Abstract: A roller includes a cylindrical body having openings on both ends thereof and a press-fit member fitted in at least one of the openings of the cylindrical body with an outer circumferential face thereof in contact with an inner face of the cylindrical body. The outer circumferential face of the press-fit member is grooved obliquely to an axis of the cylindrical body, and the inner face of the cylindrical body is smooth at least in a portion that contacts the outer circumferential face of the press-fit member.

Abstract: A rotary piston pump equipped with a motor having two counter-rotating rotary pistons. The two rotary pistons are housed in an oval pump housing. The two rotary pistons are arranged on a first output shaft and a second output shaft. The first output shaft and the second output shaft are driven and synchronized via at least one elastic element.

Abstract: An apparatus for use in a wellbore may include a stator having a bore and a rotor disposed in the bore. Either or both of the rotor and the stator may include a layer that has an asymmetrical material property profile along at least a portion of a circumference of that layer.

Abstract: The invention concerns a vane cell machine having a stator and a rotor that is made of a first material, the rotor having guides comprising radially displaceable vanes that rest on an inside of the stator and border work chambers at each axial end of the rotor together with the rotor, the stator and individual stationary side walls, the vanes having, at least at some contact faces with the rotor and the stator, a second material that interacts unfrictionally with the first material. It is endeavoured to keep the wear small. For this purpose, in a radially inner area, the side wall comprises a surface of a third material interacting unfrictionally with the first material and, in a radially outer area a surface made of the first material.

Abstract: A progressive cavity type motor or pump including a stator insert with a reinforcing agent dispersed in a manner to improve properties of the stator insert. The reinforcing agent may be a fiber, nanotube, metal, ceramic, or polymer. A dispersing agent may be used to obtain a homogenous distribution. A magnetic reinforcing agent may be incorporated into a stator insert. The stator insert is subjected to a magnetic field to orient the magnetic reinforcing agent in a particular orientation. The magnetic field may also reposition the magnetic reinforcing agent within the stator insert. The stator insert may be formed by injection molding, transfer, or compression molding among other methods.

Abstract: The present invention recites a method of fabricating a stator for a downhole motor, the method comprising the steps of providing a stator tube having an interior surface and applying a bonding agent to the interior surface of the stator tube. Additionally, a mandrel is positioned within the stator tube, the mandrel having an outer geometry that is complimentary to a desired inner geometry for the stator. Furthermore, a reinforcing material is introduced into the stator tube to fill space between the mandrel and the interior surface of the stator tube and subsequently solidified to bond the reinforcing material to the interior surface of the stator tube. The mandrel is then removed from the bonded stator tube and reinforcing material such that a stator is fabricated.

Abstract: A progressing cavity pump/motor includes a stator (12) having a metal interior surface (14) and one or more spiraling internal lobes (16). The rotor (18) has a metal exterior surface (20) and one or more spiraling external lobes (22) for cooperating with the stator to form progressing cavities between the stator and the rotor during rotation of the rotor. At least one of the stator interior surface and the rotor exterior surface include a plurality of spaced grooves (30) in the respective surface, such that fluid flowing to a gap between the stator and the rotor is disrupted by the spaced grooves to reduce fluid leakage between the stator and the rotor.

Abstract: In an aspect, the disclosure provides an apparatus for use downhole. In one aspect the apparatus includes a rotor with lobes disposed in stator with lobes, wherein at least one of the contours of the rotor lobe and the contour of the stator lobe is asymmetric.

Abstract: The rotary diaphragm pump has a flexible, resilient diaphragm band surrounding an elliptical frame within a case having four chambers surrounding an elliptical core. An articulating mechanism has a plurality of wheels traveling along the elliptical edges of the frame. The mechanism extends and retracts as the wheels move from maximum extension along the major axis of their elliptical tracks to minimum extension at the minor axis of their tracks. This mechanism drives a pair of actuator rollers along the inner surface of the diaphragm, periodically forcing the diaphragm into the surrounding chambers to produce the pumping action. Each chamber has an inlet port and an outlet port. The various ports may be interconnected to provide one or more multi-stage pumps in combination with one or more single-stage pumps, as desired. Two or more pumps may be joined in tandem to provide greater capacity from a single drive shaft.

Abstract: This disclosure describes new construction for rotary elements that find use in rotary displacement devices, e.g., positive displacement pumps and meters. The proposed construction may incorporate fibers, e.g., carbon fibers, disposed in a resin matrix. This construction can reduce the need to perform secondary processes that are necessary to utilize many rotary elements of conventional design. Moreover, examples of the rotary elements can improve operation of the displacement devices, e.g., by reducing resonance and allowing the displacement device to operate at increased speed.

Abstract: A fluid pump includes a motor, an inner gear rotor and an outer gear rotor. The inner gear rotor is driven for rotation about an axis by the motor and has a plurality of outwardly extending teeth. The outer gear rotor has a plurality of inwardly extending teeth that are engaged by the teeth of the inner gear rotor so that the outer gear rotor is driven for rotation about a second axis when the inner gear rotor rotates. At least one of the inner gear rotor and the outer gear rotor is formed from a plastic material.

Abstract: According to one embodiment of the invention, a gerotor apparatus includes an outer gerotor having an outer gerotor chamber, an inner gerotor, at least a portion of which is disposed within the outer gerotor chamber, and a synchronizing apparatus operable to control the rotation of the inner gerotor relative to the outer gerotor. The inner gerotor includes one or more entrance passages operable to communicate a lubricant into the outer gerotor chamber.

Abstract: The present invention recites a method of fabricating a stator for a downhole motor, the method comprising the steps of providing a stator tube having an interior surface and applying a bonding agent to the interior surface of the stator tube. Additionally, a mandrel is positioned within the stator tube, the mandrel having an outer geometry that is complimentary to a desired inner geometry for the stator. Furthermore, a reinforcing material is introduced into the stator tube to fill space between the mandrel and the interior surface of the stator tube and subsequently solidified to bond the reinforcing material to the interior surface of the stator tube, The mandrel is then removed from the bonded stator tube and reinforcing material such that a stator is fabricated.

Abstract: An eccentric-screw pump has an axially split stator having axially opposite intake and output ends and an elastomeric liner defining an axially throughgoing passage. Respective intake and output housings are releasably secured to the intake and output ends of the stator. An axially extending screw rotor in the passage has an end in the intake housing. A drive includes a rotatable universal joint having a pair of relatively swivelable parts in the intake housing. Respective generally complementary formations on the end of the rotor and on one of the universal-joint parts can fit axially together to rotationally couple the one universal-joint part with the rotor. A latch secures the formations axially together for angular force transmission between the one universal-joint part and the rotor.

Abstract: Vane pump mechanical losses are reduced by removing vane friction losses and replacing them with lower magnitude journal bearing fluid film viscous drag losses. A freely rotating cam ring is supported by a journal bearing. A relatively low sliding velocity is imposed between the cam ring and the vanes. This permits the use of less expensive and less brittle materials in the pump by allowing the pump to operate at much higher speeds without concern for exceeding vane tip velocity limits.

Abstract: The present disclosure relates to a simplified roots-type blower having an improved sound signature. The roots-type blower includes a rotor bore housing having a molded, one-piece polymeric construction. The rotor bore housing defines a first rotor bore and a second rotor bore. The rotor bore housing also defines a first bearing pocket corresponding to the first rotor bore and a bearing pocket corresponding to the second rotor bore axis. The rotor bore housing further defining a timing gear chamber.

Abstract: A rotary pump device is provided in which a drive shaft is inserted into a center hole of a cylinder that forms rotor chambers, and into outer rotors and inner rotors of rotary pumps. In the rotary pump device, seal mechanisms that include hollow-shaped resin members and annular rubber members are arranged on an opposite side to the cylinder with respect to the rotary pumps. Metal rings are arranged in hollow portions of the resin members in the seal mechanisms so that the drive shaft is inserted into an inner periphery of the metal rings with a minimum clearance.

Abstract: The invention relates to an internal gear pump for a braking system, in the pump housing of which an inner toothed hollow wheel and a gearwheel engaging in the toothing of the hollow wheel are mounted to rotate about parallel axes. The toothing thereof defines a tapering roughly crescent-shaped pump chamber, in which a filling piece is arranged supported along the length thereof. The circumferential surfaces of the filling piece closely correspond to the head diameter of the inner toothing of the hollow wheel or the gearwheel toothing and contact in a sealing manner with several tooth crowns covered thereby. A radial supporting force acts over a longitudinal range of the filling piece for improved sealing of a circumferential surface of the filling piece against the tooth crowns supporting the circumferential surface.

Abstract: A device configured for converting energy includes a first surface, a second surface configured for moving with respect to the first surface during operation of the device, and a coating disposed on at least one of the first surface and the second surface. The coating includes a first layer of a ceramic alloy represented by the general formula AlMgB14—X, wherein X is present in an amount of from 0 to 70 parts by weight based on 100 parts by weight of the ceramic alloy and is a doping agent selected from the group of Group IV elements and borides and nitrides thereof, and a second layer disposed on the first layer and including carbon in a gradient concentration. The coating has a hardness of from 10 to 20 GPa and a coefficient of friction of less than or equal to 0.12.

Abstract: A fluid device includes a housing and a rotor assembly disposed in the housing. The rotor assembly includes a core and a coating. The core has a first surface, an oppositely disposed second surface and an outer peripheral surface that extends between the first and second surfaces. The core defines a bore that extends through the first and second surfaces. The coating coats at least a portion of the core. The coating is a water-swellable plastic material.

Abstract: The present application discloses a progressive cavity motor or pump component, either stator or rotor, which provides a high glass transition temperature polymeric surface on the component which becomes resilient at or below the expected operating temperature of the motor or pump, but which remains solid at ambient temperatures, along with a method of fabricating either a stator or a rotor with such surface characteristics. Since the surface becomes resilient, the progressive cavity pump operates efficiently at temperatures above the glass transition temperature of the selected polymeric surface.

Abstract: A progressing cavity pump assembly utilizes a reinforced upper section of the stator rubber helix. The pump stator is located at the end of a string of tubing. The reinforced upper section of the stator rubber helix is strong enough, whether reinforced by mechanical means or by strengthening the rubber matrix chemically, so as not to allow the passage of a stop located above or on the top of the pump rotor. The rotor is lowered on a string of rods until the stop above or on top of the rotor lands onto the reinforced upper section of the stator rubber helix. The rotor is then repositioned away from the stator helix a predetermined distance before pump operation begins with rod string rotation.

Abstract: The invention concerns a vane cell machine having a stator and a rotor that is made of a first material, the rotor having guides comprising radially displaceable vanes that rest on an inside of the stator and border work chambers at each axial end of the rotor together with the rotor, the stator and individual stationary side walls, the vanes having, at least at some contact faces with the rotor and the stator, a second material that interacts unfrictionally with the first material. It is endeavoured to keep the wear small. For this purpose, in a radially inner area, the side wall comprises a surface of a third material interacting unfrictionally with the first material and, in a radially outer area a surface made of the first material.

Abstract: In a pump system, a process fluid is directed into inlet chambers of a pump casing at an inlet pressure, and a plurality of rotors disposed inside the pump casing are rotated to pump the process fluid from the inlet chambers to an outlet chamber located between the inlet chambers, wherein the process fluid in the outlet chambers is at an outlet pressure. The process fluid is directed from the outlet chamber to a separator configured to separate particulate matter from the process fluid, and a portion of separated process fluid is directed from the separator to a gear chamber of the pump. Pump bearings are lubricated with the portion of separated process fluid from the gear chamber. Some of the portion of the separated process fluid from the pump bearing is leaked to the inlet chambers via rotor shrouds to reduce accumulation of particulate matter in the inlet chambers.

Abstract: An upper casing receives a rotor, which is rotated by a drive force of a motor. The upper casing includes a pump chamber, which receives the rotor, a planar surface portion, which is formed around an opening of the pump chamber, and a through hole. A lower casing includes a planar surface portion, which is formed around the opening of the pump chamber, and a through hole. The lower casing closes the opening of the pump chamber to form the pump chamber in cooperation with the upper casing. A resilient sheet is placed between the lower casing and a mount portion of the motor and includes a through hole. A screw is received through the through holes of the upper casing, the lower casing and the resilient sheet to securely connect the upper casing, the lower casing and the resilient sheet to the mount portion. A lower casing side surface of the resilient sheet includes a plurality of primary protrusions.