Abstract: A caliper brake (10) includes a housing (12) formed of a first housing portion (16) and a second housing portion (18). Each of the first housing portion and second housing portion include a channel (104) extending therethrough. The channels (104) include pins (102) for receiving one or more shims (94) thereon. Brake (10) includes a first stator assembly (60) and a second stator assembly (64) that are separated by a first distance when no shims (94) are on the pins (102). The first stator assembly (60) and the second stator assembly (64) are separated by a second distance less than the first distance when one or more shims (94) are on the pins (102).

Abstract: A brake disc to be mounted on an axle hub, including sliding surfaces with which friction members respectively come into a sliding contact and which face in mutually opposite directions, wherein the brake disc includes: a first member having a disc-like shape and including a mount portion through which the brake disc is mounted on an axle hub and a radially outer portion located radially outward of the mount portion, one of the sliding surfaces being formed on the radially outer portion; and a second member having a doughnut plate shape, the other of the sliding surfaces being formed on the second member, and wherein the first member and the second member are bonded through a protruding portion formed on one of the radially outer portion of the first member and the second member and protruding toward the other of the radially outer portion and the second member.

Abstract: A quality value for a carbon ceramic brake disc (2) in a vehicle is measured by means of a measuring device (3) installed in the vehicle. The measuring device (3) with a coil (10) is located at a distance (d) from the brake disc (2) in order avoid direct physical contact with the brake disc. The impedance of the coil (10) is measured for at least two frequencies. The resulting measurement values that correlate to impedance values are introduced into a mathematical model in order to eliminate the dependence of the unknown distance (d) and to obtain a quality value dependent on the conductivity of the brake disc (2).

Abstract: A brake pad apparatus having a conductivity sensor disposed thereon operable to generate conductivity data corresponding to the remaining thickness of the brake pad's friction lining. The conductivity data may be analyzed by a processor to estimate the remaining life of the brake pad for purposes of maintenance, diagnostic, or repair. The conductivity sensor may utilize a conductivity probe that comprises one or more insulation coatings to insulate conductive material from the friction lining. The brake pad apparatus may further comprise a wireless transmitter to transmit data to a processor external to the brake pad apparatus.

Abstract: A torsion spring assembly according to the invention includes a torsion spring having a cylindrical spring body of wound spring wire and with a plurality of torsion spring windings, and having first and second torsion spring ends for taking up forces in a direction of rotation, and a damping spring abutting the torsion spring on the inner side and having a cylindrical spring body of wound spring wire and with a plurality of damping spring windings, and having first and second damping spring wire ends, wherein the damping spring windings have their outer sides extending partially into the space formed between two respectively adjacent torsion spring windings and abutting in particular rounded, round or beveled inner abutment areas of respectively adjacent torsion spring windings with substantially radially outwardly directed bias.

Abstract: A second dynamic vibration absorber is higher in resonance frequency than a first dynamic vibration absorber. At least one of the resonance frequency of the first dynamic vibration absorber or the resonance frequency of the second dynamic vibration absorber is shifted from associated at least one of the first resonance frequency or the second resonance frequency such that a peak frequency of antiresonance occurring in a higher frequency region of the first dynamic vibration absorber than the resonance frequency of the first dynamic vibration absorber is substantially different from that of antiresonance occurring in a lower frequency region of the second dynamic vibration absorber than the resonance frequency of the second dynamic vibration absorber.

Abstract: An adjustable damping valve device for a vibration damper, includes a main stage valve which is controlled by a pre-stage valve with a pre-stage valve body, which pre-stage valve can be actuated by an electromagnetic actuator, wherein an emergency operation valve controls the main stage valve during emergency operation, wherein an emergency operation armature is preloaded on the pre-stage valve body of the pre-stage valve by an emergency operation spring so that the pre-stage valve forms the emergency operation valve.

Abstract: A vibration damper with a hydraulic end stop includes a cylinder in which a sleeve of plastic is axially fixed as part of the end stop. The sleeve has a circumferential collar on the outer side, via which collar the sleeve is axially supported at the cylinder side. The sleeve is supported via the circumferential collar directly on a carrying ring which has an L-shaped cross section and is axially clamped between an end face at the end of the cylinder and a piston rod guide of the vibration damper.

Abstract: A shock absorber includes a cylinder; a piston dividing the cylinder into first and second chambers, the piston being movable within the cylinder in inward and outward directions; a first main channel and a first main non-return valve allowing a first main fluid flow from the second to the first cylinder chamber; a second main channel and a second main non-return valve allowing a second main fluid flow from the first to the second cylinder chamber; a comfort channel allowing an auxiliary fluid flow between the first and second cylinder chambers; and a comfort valve providing an open connection for the auxiliary fluid flow through the comfort channel in a rest position of the comfort valve and closing off the auxiliary fluid flow at increasing pressure difference across the comfort valve at either inward or outward movement to influence an auxiliary fluid flow between first and second piston sides.

Abstract: A high-voltage connection device for use with an electrorheological device having a high-voltage connector with an insulating upper part, an insulating lower part, a connector socket, and a central metallic contact pin, wherein the connector socket is fixed to a grounded portion of the electrorheological device and the upper part contains ground terminal elements and is axially connected to the lower part. Additionally, the upper part has a pot-like design and coaxially surrounds both the lower part and the connector socket in the connected state.

Abstract: A restricted passageway (24) is provided with a first communication part (26) which is formed in a first barrier wall (34) facing a first liquid chamber and opens to the first liquid chamber, a second communication part (27) which is formed in a second barrier wall (35) facing a second liquid chamber and opens to the second liquid chamber, and a main body flow path (25) that is configured to cause the first communication part (26) and the second communication part (27) to communicate with each other. At least one of the first communication part (26) and the second communication part (27) includes a plurality of fine holes (26a) that pass through the first barrier wall (34) or the second barrier wall (35).

Abstract: The present invention provides a liquid-filled vibration isolator with improved durability. The liquid-filled vibration isolator includes a shaft unit, a first unit, an elastic body coupling the first unit and shaft unit, and a second unit mounted radially outside the first unit. The first unit includes a pair of annular elements, a pair of coupling elements coupling the annular elements, while the elastic body includes outer face portions bonded to outer surfaces of the coupling elements. The outer face portions include lips making contact with the second unit, and first segments making contact with the second unit on areas larger than the lips. The second unit restrains the annular elements along the entire circumferences, and compresses the lips and first segments in the radial direction.

Abstract: A passive variable negative stiffness device (passive VNSD) configured to facilitate a transition to zero stiffness by using elastic devices (e.g., springs) combined with translating and rotating components. An exemplary embodiment of a passive VNSD may comprise at least one pretensioned and/or precompressed elastic device to produce the desired force-displacement profiles. For instance, an exemplary embodiment of a passive VNSD may be adapted to produce force-displacement profiles that transition from zero stiffness, to negative stiffness, and then to positive stiffness (ZNP) and from zero stiffness, to negative stiffness, and then back to zero stiffness (ZNZ).

Abstract: A dynamic vibration absorber is configured to be attached to a rotary member. The dynamic vibration absorber includes a base member, a mass body, and a torque limiting part. The base member is rotatably disposed. The mass body is attached to the base member so as to be rotatable relatively thereto. The torque limiting part limits transmission of a torque to be inputted into the base member from the rotary member.

Abstract: A rotary viscous vibration damper or absorber has a hub part which can be fastened to a crankshaft of an engine, in particular of an internal combustion engine, and a vibration damper ring which is mounted such that it can be rotated relative to the hub part. A shear gap which is filled with a silicone oil is formed between the hub part and the vibration damper ring, in which shear gap flange bushings for guiding the vibration damper ring are mounted. The flange bushings are composed of a liquid crystal polymer.

Abstract: A V-ribbed belt includes a compression rubber layer containing a vulcanizate of a rubber composition, a tension member, and a tension layer, and has a side part of the compression rubber layer being a ground surface coming into contact with pulleys, and a bottom part of the compression rubber layer being a non-ground surface not coming into contact with pulleys. The V-ribbed belt has, on a surface of the bottom part, a composite layer containing a fiber assembly and a vulcanizate. The fiber assembly contains a heat-resistant fiber which is not melted at a vulcanization temperature of the rubber composition and has a weight per unit area of 25 g/m2 or less. The vulcanizate of the rubber composition impregnated among fibers of the fiber assembly.

Abstract: A drive chain includes a plurality of outer plates, inner plates and pins. Each outer plate has two outer pivoting holes and two first protruding surfaces. A virtual line connecting the centers of the outer pivoting holes of each outer plate is defined as a first major axis. Each inner plate has two inner pivoting ends and a first protruding portion. A virtual line connecting the centers of the two inner pivoting holes of each inner plate is defined as a second major axis. The first protruding portion has a second protruding surface. Each pin is threaded through two inner plates and two outer plates. An included angle is formed between the first and second major axes. The first protruding surface contacts and overlaps the second protruding surface to form an overlapping region whose area decreases as the included angle decreases.

Abstract: In a planetary gear device series composed of eight kinds of planetary gear devices with gear reduction ratios of 3 to 10, the planetary gear device of each gear reduction ratio uses an internal gear with 108 teeth or a slightly different number of teeth, and the module is common among the planetary gear devices of all gear reduction ratios. The combinations of the sun gear teeth number Za and the internal gear teeth number Zc in the planetary gear device of each reduction ratio are given in Table 1 of this application.

Abstract: A speed reducer includes an input shaft, an output shaft, and a gear assembly coupled to the input shaft. The gear assembly includes a housing, an external gear, and at least two internal gears. The external gear is located within the housing and inscribes the at least two internal gears. One side of the at least two internal gears is rotatably coupled to the input shaft, and another side of the at least two internal gears is coupled to a connecting column of the output shaft. The at least two internal gears are offset on the input shaft, and the input shaft drives the at least two internal gears to maintain engagement with the external gear. The connecting column maintains transmission of the output shaft and the at least two internal gears.

Abstract: A gearbox includes a first shaft operatively coupled to an output of an engine, with the first shaft having a first longitudinal axis. A second shaft is operatively coupled to a driveshaft of an electric machine, the second shaft having a second longitudinal axis. The second longitudinal axis is non-coaxial with the first longitudinal axis. A geartrain operatively couples the first and second shafts. The geartrain is structured to passively switch between a first gear ratio and a different second gear ratio.

Abstract: Described is a device for synchronization of a reverse gear for a vehicle gearbox including: a support shaft fixed in rotation; an idle gear wheel for engagement with a first reverse gear wheel on a gearbox primary shaft and a second reverse gear wheel on a gearbox secondary shaft, said idle gear wheel mounted rotatable and axially slidable on said support shaft and having a hub including a first friction surface; and a synchronizer ring mounted mobile on said support shaft along an axial travel and countered axially by an elastic element along said axial travel, said synchronizer ring having a second friction surface for engagement with said first friction surface. Axial movement of the idle gear wheel towards an engagement position of the reverse gear causes drawing of the synchronizer ring implementing, prior to reverse gear engagement, braking of rotary movement of the idle gear wheel.

Abstract: An automatic transmission realizes forward 10-speed and reverse 1-speed shift stages by including an input shaft; a first planetary gear set; a second planetary gear set connected through one part and selectively connected through another part with the first planetary gear set, and receiving power from the input shaft; a third planetary gear set connected with the first planetary gear set through one part and selectively connected with the first planetary gear set through another part, and selectively connected with the second planetary gear set; a fourth planetary gear set selectively connected to a transmission housing, selectively connected with the first planetary gear set, selectively connected with the second planetary gear set, and connected with the third planetary gear set through one part and selectively connected with the third planetary gear set through another part; and an output shaft connected with the third planetary gear set, and outputting speed-shifted power.

Abstract: A transmission device for a motor vehicle includes a final drive and a planetary gearset. The planetary gearset has a first transmission element formed by a first ring gear, which first transmission element has external teeth for introducing a drive torque, at least one second transmission element and at least one third transmission element, which is coupled to the final drive. The device also has a brake element for lockingly braking at least one of the transmission elements of the planetary gearset. The final drive is a planetary differential, which is arranged radially inside the planetary gearset and is arranged in a gearwheel level with the planetary gearset.

Abstract: An electronically controlled variable speed mechanical drive to be used in high power applications where using a direct drive motor is not feasible due to weight and size constraints. The variable speed drive components convert an externally driven fixed displacement pump into a variable displacement pump by electronically setting the pump speed to meet flow demands. A single stage pump and a multi-stage pump are so converted, according to the present disclosure.

Abstract: A tensioner comprising a base having a cylindrical portion extending axially, the cylindrical portion comprising a radially outer surface and a receiving portion that is radially inward of the radially outer surface, an eccentric arm pivotally engaged with the radially outer surface, a torsion spring disposed within the radially inward receiving portion, the torsion spring applying a biasing force to the eccentric arm, and a pulley journalled to the eccentric arm.

Abstract: A belt-driven linear module includes a tensioning assembly and a drive belt. The tensioning assembly includes a support shaft and a bearing. The support shaft is configured to be installed at a driven end of the linear module. The bearing includes an inner ring and an outer ring. The inner ring is positioned on the support shaft, and the outer ring is configured to be wrapped by the drive belt of the linear module so as to tension the drive belt of the linear module.

Abstract: A gearbox includes a planetary gearset, an input shaft coupled to a sun gear of the planetary gearset, and an output shaft coupled to planet gears of the planetary gearset via a carrier. A constant torsion spring is coupled to a ring gear of the planetary gearset. The constant torsion spring is capable of preventing the ring gear from moving when a torque at the output shaft is below a threshold. The ring gear winds the constant torsion spring in response to the torque exceeding the threshold.

Abstract: A power transmission apparatus includes a first input shaft selectively receiving an input torque, a second input shaft coaxially disposed with the first input shaft and selectively receiving the input torque, first and second intermediate shafts selectively interconnected and disposed in parallel with the first input shaft, a torque mediating shaft coaxially disposed with the first input shaft, a preliminary shifting section receiving a torque through a first input shaft and selectively outputting a shifted torque to the second intermediate shaft, a compound shifting section including a planetary gear set having a sun gear fixedly connected with the torque mediating shaft, a planet carrier fixedly connected with the second input shaft, and a ring gear externally gear-meshed with the second intermediate shaft, and an output shaft receiving a torque received from the compound shifting section and transmitting the received torque to a differential.

Abstract: A transmission comprising a motor, a torque converter cover including an outside surface and an inside surface, a clutch configured to contact a portion of the inside surface of the torque converter cover, and a sprayer including a first end and a second end and configured to emit fluid on an outside surface of the torque converter is disclosed.

Abstract: The present invention relates to a hydraulic unit with a housing in which a hydraulic converter is accommodated, which is coupled with a drive shaft that includes a connecting shaft piece located outside the housing for connection to a mechanical drive element The invention furthermore relates to a hydraulic driving device with such hydraulic unit and to a drive train connecting piece to which the hydraulic unit is connected. It is proposed to integrate a clutch for connecting and disconnecting the hydraulic unit into the hydraulic unit itself, so that a mechanical drive train, to which the hydraulic unit is connected, can remain unchanged or need not especially be adapted to the clutch. In accordance with the invention, a clutch for coupling and uncoupling the connecting shaft piece of the hydraulic unit to and from the hydraulic converter of the hydraulic unit is accommodated in the housing of the hydraulic unit.

Abstract: A vehicle comprises a hydromechanical automatic gearbox, an automatic gear shift unit (12) connected to a pressure fluid feeding pump (15). The gearbox comprises an input shaft (4) extending from an engine, gearing (23) extending to each gear step, wherein the gearing (23) is mounted on the input shaft (4) and is as a central gear (2), located on the input shaft (4), meshing with gear wheels (3) of different gear steps having different diameters mounted on the input shaft (4) of a single hydraulic torque converter (5) comprising a pump (6) and a turbine (8) located accordingly on the input (4) and output (7) shafts thereof forming a flow path of pressure fluid, each of the hydraulic torque converter (5) is electronically and hydraulically linked to the gear shift unit (12) of the vehicle.

Abstract: A power-driven system includes: a differential; a power output shaft configured to link to a power input end of the differential; multiple input shafts; and a first motor generator. The differential includes a first planet carrier, a second planet carrier, a first planet gear, a second planet gear, a first ring gear, and a second ring gear. The first planet gear and the second planet gear are respectively disposed on the first planet carrier and the second planet carrier and respectively meshed with the first ring gear and the second ring gear. One input shaft of the multiple input shafts is configured to selectively link to the power output shaft, and another input shaft of the multiple input shafts is configured to link to the power output shaft. The first motor generator is configured to link to the one input shaft of the multiple input shafts.

Abstract: A method of making a strain wave includes the steps of a) providing a circular spline, a flexspline meshed with the circular spline, and an initial wave generator having an initial outer profile of a standard ellipse with a perimeter S0, and b) producing a modified wave generator rotatably fitted within the flexspline and having a modified outer profile with a perimeter S. A difference ES between the perimeter S of the modified outer profile and the perimeter S0 of the initial outer profile satisfies the equation ES=S?S0=0.1 m to 0.8 m, wherein m is the modulus of the flexspline. Through a special parameter design of the modified wave generator, the meshing ratio between the circular spline and the flexspline is increased, thereby improving the transmission accuracy and reducing the average load.

Abstract: A circular spline is secured to a housing. An output member is positioned relative to the circular spline, an outer race of a bearing is secured to the housing, and an inner race of the bearing is secured to the output member. A flex spline is positioned relative to the circular spline and secured to the output member. A wave generator is positioned relative to the circular spline, and a support member, by which the wave generator is rotatably supported, is secured to the housing.

Abstract: A governor drive gear for use in an integrated drive generator has a gear body extending between a first end and a second end and having a disc extending radially outwardly. A boss extends from the disc toward the second end. There are outer gear teeth outwardly of an outer diameter of the disc. The outer gear teeth have a unique gear tooth profile with roll angles A, B, C, and D. An integrated drive generator and a method are also disclosed.

Abstract: The present embodiments relates to a reducer of an electric power steering device. An embodiment of the present embodiments provides a reducer of an electric power steering device, including: a worm shaft having a first worm shaft bearing and a second worm shaft bearing coupled to one end portion, which is connected to a motor shaft, and to the other end portion, which is opposite thereto, respectively; a gear housing that contains the first worm shaft bearing, the second worm shaft bearing, and the worm shaft; and a support member coupled to the inner peripheral surface of the hear housing so as to support the outer race of the second worm shaft toward the worm wheel and filled with a viscoelastic fluid.

Abstract: In a transmission housing unit having a housing base body for a shaft, which is supported with a compensating arrangement between a second end face and a second guide surface. The compensating arrangement has an axial disk. The axial disk and the housing base body have corresponding geometric unbalances in accordance with the poka-yoke principle such that the axial disk is only insertable in a single orientation into the housing base body in the assembly condition.

Abstract: A transmission assembly structure includes an engine-side joining surface, a transmission-side joining surface, which is joined to the engine-side joining surface, an engine component which is provided on an outside of the engine-side joining surface in a radial direction in the flywheel housing and protrudes toward the transmission side, a guide member which is provided on the engine-side joining surface or in the vicinity of the engine-side joining surface of the flywheel housing and in a vicinity of the engine component and which protrudes toward the transmission side further than the engine component, and a guide hole, which is provided on the transmission-side joining surface of the transmission housing or in the vicinity of the transmission-side joining surface and into which the guide member is inserted.

Abstract: In a machine or vehicle component comprising a first housing part, a second housing part covering the first housing part, an opening which is provided in the second housing part, a functional attachment unit incorporating a mounting element consisting of a structurally rigid material which extends through the opening, it is proposed that the problem that the functional attachment unit can only be mounted on the second housing part if the structural rigidity thereof is sufficient to hold the functional attachment unit permanently in a stable position be solved in that the second housing part is formed from a thermoplastic material of low structural rigidity and in that there is provided a carrier which incorporates a carrying element consisting of a structurally rigid material and is fixed relative to the first housing part and upon which the attachment unit is held by means of the mounting element.

Abstract: A transfer gearbox may include an input shaft, two output shafts, two output gears, two sets of compensating gears, and a differential cage. The output gears may be arranged axially next to one another on a joint axis of rotation and are rotatable relative to one another. The first output gear may sit in a rotationally fixed manner on the first output shaft and the second output gear may sit in a rotationally fixed manner on the second output shaft and the output shafts lie opposite one another at a front side. At least one output shaft may be guided through a shaft feed-through rotatably about the axis of rotation relative to the shaft feed-through. At least the first output gear may be provided with a seal, wherein the seal bears in a sealing manner against a rotationally symmetrical surface portion of the shaft feed-through.

Abstract: A spur gear transmission has at least two meshing, toothed spur gears. A covering wall surrounds the spur gears circumferentially and in the direction of their rotational axes. The covering wall has an inner contour adapted to the outer diameters of the spur gears. Two annular gaps which transition into each other are formed between the covering wall and the spur gears. The annular gap is substantially concentric to a rotational axis. The covering wall surrounds the two spur gears circumferentially only over a part of the circumference, with a part of the outer circumference of the two spur gears or one of the two spur gears protruding outwards out of the covering wall. The part of the two spur gears or of the one spur gear that protrudes out of the covering wall is positioned on the lower face of the spur gears.

Abstract: A vehicle system is disclosed. The vehicle system includes an automatic transmission fluid cooling conduit. The automatic transmission fluid cooling conduit includes an inlet portion, an outlet portion, and an elbow portion connecting the inlet and outlet portions and having an inner surface defining a cavity in fluid communication with the inlet and outlet portions. The automatic transmission fluid cooling conduit also includes an oleophobic or hydrophobic coating on the inner surface. The oleophobic or hydrophobic coating is configured to reduce eddy currents in the cavity.

Abstract: A planetary roller transmission includes: a fixed ring; a sun shaft; a plurality of planetary rollers; a carrier that has a plurality of support shafts that support the planetary rollers via bearing portions and that revolves together with the planetary rollers; and an annular flange ring provided on one side, in the axial direction, of the fixed ring and the planetary rollers. The inside diameter of the flange ring is smaller than the diameter of a circumscribed circle circumscribed by bearing portions which are arranged in the circumferential direction. An oil storage portion that receives oil that has climbed over the flange ring from the side of the planetary rollers is provided between a side surface of the flange ring and an inner wall surface of the housing. A passage that allows oil to permeate from the oil storage portion to the side of the planetary rollers is provided.

Abstract: A power transmission apparatus including: a case having a first oil storage configured to store oil at a bottom thereof; a rotating body rotatably housed in the case and having a second oil storage configured as an approximately cylindrical rotating body for transmitting power and configured to store oil therein; and an introducing portion configured to introduce oil from the first oil storage into the second oil storage.

Abstract: A gear assembly includes gears, housing components joined to one another about the gears, and a gasket. Each housing component includes an axial end wall and a sidewall projecting axially from the axial end wall. The sidewall of each housing component has an axial end surface that faces the axial end surface of the other housing component. One of the housing components includes a rib that projects axially from the axial end wall thereof and is spaced inward from the sidewall thereof. The gasket includes a seal portion and a baffle portion. The seal portion is disposed between the axial end surfaces of the housing components to create a seal therebetween. The baffle portion extends inward from the seal portion and cooperates with the rib, the sidewall, and the axial end wall to form a channel configured guide drainage of lubricant thrown from at least one of the gears.

Abstract: A differential apparatus having a pinion gear revolving around an axial line and a side gear engaging with the pinion gear and configured to transmit power by rotation of the side gear, including: a differential case housing the pinion gear and the side gear and rotating around the axial line; and an intermediate member disposed between the side gear and an inner wall of the differential case. The intermediate member has a scooping-up portion scooping up oil outside of the differential case.

Abstract: An epicyclic gear train including a central sun gear, an outer ring gear, and a number of planet gears which are mounted to a planet carrier. The planet carrier includes a centrally disposed torque transfer coupling with a torque transmission point at an axial end thereof. First and second carrier plates extend radially from the torque transfer coupling and are axially spaced apart to support the planet gears therebetween at aligned gear mounting points. The first carrier plate is closer to the torque transfer point than the second carrier plate. The second carrier plate has a stiffness that is greater than that of the first carrier plate.

Abstract: A mechanical transmission device having a planet carrier and at least two planets mounted on the planet carrier by means of respective rotation shafts. The device includes a stop for stopping movement of the various rotation shafts in axial translation.

Abstract: A shift-by-wire shifting control apparatus for a vehicle includes a housing, and a D-gear switch, an N-gear switch, and an R-gear switch installed in the housing. The D-gear switch corresponds to a drive gear, the N-gear switch corresponds to a neutral gear, and the R-gear switch corresponds to a reverse gear. A specific switch that is one of the D-gear switch, the N-gear switch, and the R-gear switch is movable from the first position to a third position between the first and second position by a first pressing force and is movable from the third position to the second positions by a second pressing force greater than the first pressing force.

Abstract: In a hydraulic control device, a state determination unit of a control unit determines whether a second pump is in a boosting operation or in a transition state. If the state determination unit has determined that the second pump is in the boosting operation or in the transition state, a valve-opening detection unit determines whether a check valve is opened. If the valve-opening detection unit has determined that the check valve is opened, a controller stops the second pump or decreases the rotation number of the second pump.