Abstract: A direction-of-arrival estimation device for achieving direction-of-arrival estimation which is robust against an SNR and in which an application range of a learning model is specific is provided.

Abstract: A hydraulic hammering device includes a piston front chamber and a piston rear chamber defined between an outer circumferential surface of the piston and an inner circumferential surface of the cylinder and disposed separately from each other at front and rear, respectively, in an axial direction. A switching-valve mechanism drives the piston by switching at least one of the piston front chamber and the piston rear chamber into communication with at least one of a high pressure circuit and a low pressure circuit. An acceleration piston is disposed behind the piston and is configured to come into contact with the piston during a retreat stroke thereof to urge the piston forward, in which a timing where the acceleration piston itself starts to come in contact with the piston is set to be earlier than a timing where the piston is braked by the switching-valve mechanism.

Abstract: Provided is a two-piston hydraulic striking device that has stable operativity. This two-piston hydraulic striking device includes two striking mechanisms for striking one transfer member. Each striking mechanism has a pressure receiving area ratio between the front and rear of a piston thereof set in such a way that the two striking mechanisms have the same cycle time.

Abstract: Hammering power of a hydraulic hammering device is improved by shortening a piston stroke, while keeping hammering energy. The device includes a cylinder, a piston slidingly fitted in the cylinder, and a piston front chamber and a piston rear chamber defined between an outer circumferential surface of the piston and an inner circumferential surface of the cylinder and disposed separately from each other at front and rear, respectively, in an axial direction. The device also includes a switching-valve mechanism driving the piston by switching at least one of the piston front or rear chamber into communication with at least one of a high pressure circuit or a low pressure circuit, and an acceleration piston disposed behind the piston and coming in contact with the piston during a retreat stroke of the piston to urge the piston forward in cooperation with braking force by pressurized oil acting on the piston.

Abstract: A hydraulic hammering device is capable of sufficiently transmitting blow energy to bedrock while further strengthening cushioning action and suppressing damage to equipment. The device includes a pushing piston disposed behind a transmission member and having a smaller propulsive force than that of a main body, a damping piston positioned behind the pushing piston to slide reciprocally forwards and backwards and having a greater propulsive force than that of the main body, a direction-restrictor in a high-pressure circuit between pushing and damping chambers, to which hydraulic fluid is supplied for providing the pistons with propulsive forces, and a fluid supply source. The direction-restrictor restricts an outflow from the chambers side to the fluid supply source side while allowing fluid inflow from the fluid supply source side to the chambers and the pushing chamber sides. A throttle in a drain circuit discharges leaked fluid from a sliding contact location to a tank.

Abstract: A hydraulic hammering device includes a piston front chamber and a piston rear chamber defined between an outer circumferential surface of the piston and an inner circumferential surface of the cylinder and disposed separately from each other at front and rear, respectively, in an axial direction. A switching-valve mechanism drives the piston by switching at least one of the piston front chamber and the piston rear chamber into communication with at least one of a high pressure circuit and a low pressure circuit. An acceleration piston is disposed behind the piston and is configured to come into contact with the piston during a retreat stroke thereof to urge the piston forward, in which a timing where the acceleration piston itself starts to come in contact with the piston is set to be earlier than a timing where the piston is braked by the switching-valve mechanism.

Abstract: An accessory drive system for an engine 1 includes: a drive shaft (a crankshaft 21); a driven shaft (an oil pump drive shaft 31); an endless transmission member (a drive chain 33); a first tensioner disposed on a slack side of the endless transmission member (a first hydraulic tensioner 41); and a second tensioner disposed on a tight side of the endless transmission member (a second hydraulic tensioner 43). The second tensioner has a damping function to damp pushing force applied to the second tensioner by the endless transmission member in a direction opposite to a biasing direction.

Abstract: Provided is a two-piston hydraulic striking device that has stable operatively. This two-piston hydraulic striking device includes two striking mechanisms for striking one transfer member. Each striking mechanism has a pressure receiving area ratio between the front and rear of a piston thereof set in such a way that the two striking mechanisms have the same cycle time.

Abstract: A hydraulic hammering device that uses a scheme in which a front chamber is switched into communication with a low-pressure circuit when a piston advances, wherein occurrences of “galling” to the piston at a sliding contact portion with a front-chamber liner is reduced. The front chamber has the front-chamber liner fitted to an inner surface of a cylinder. A hydraulic chamber space communicating with the front chamber and filled with hydraulic oil is formed as a cushion chamber on the inner peripheral surface of a rear portion of the front-chamber liner. The cushion chamber has a second drain circuit (from first end face grooves to slits to second end face grooves), which is provided separately from a drain circuit that guides the hydraulic fluid passing through a liner bearing of the front-chamber liner to the low-pressure circuit.

Abstract: A hydraulic hammering device is capable of sufficiently transmitting blow energy to bedrock while further strengthening cushioning action and suppressing damage to equipment. The device includes a pushing piston disposed behind a transmission member and having a smaller propulsive force than that of a main body, a damping piston positioned behind the pushing piston to slide reciprocally forwards and backwards and having a greater propulsive force than that of the main body, a direction-restrictor in a high-pressure circuit between pushing and damping chambers, to which hydraulic fluid is supplied for providing the pistons with propulsive forces, and a fluid supply source. The direction-restrictor restricts an outflow from the chambers side to the fluid supply source side while allowing fluid inflow from the fluid supply source side to the chambers and the pushing chamber sides. A throttle in a drain circuit discharges leaked fluid from a sliding contact location to a tank.

Abstract: An accessory drive system for an engine 1 includes: a drive shaft (a crankshaft 21); a driven shaft (an oil pump drive shaft 31); an endless transmission member (a drive chain 33); a first tensioner disposed on a slack side of the endless transmission member (a first hydraulic tensioner 41); and a second tensioner disposed on a tight side of the endless transmission member (a second hydraulic tensioner 43). The second tensioner has a damping function to damp pushing force applied to the second tensioner by the endless transmission member in a direction opposite to a biasing direction.

Abstract: Hammering power of a hydraulic hammering device is improved by shortening a piston stroke, while keeping hammering energy. The device includes a cylinder, a piston slidingly fitted in the cylinder, and a piston front chamber and a piston rear chamber defined between an outer circumferential surface of the piston and an inner circumferential surface of the cylinder and disposed separately from each other at front and rear, respectively, in an axial direction. The device also includes a switching-valve mechanism driving the piston by switching at least one of the piston front or rear chamber into communication with at least one of a high pressure circuit or a low pressure circuit, and an acceleration piston disposed behind the piston and coming in contact with the piston during a retreat stroke of the piston to urge the piston forward in cooperation with braking force by pressurized oil acting on the piston.

Abstract: An engine piston structure includes: a piston (1); a connecting rod (10) having a small end part (10a) coupled to the piston (1), and having a large end part (10b) coupled to a crankshaft; a piston pin (2) through which the piston (1) and the small end part (10a) of the connecting rod (10) are coupled together and which has a hollow cross section; and at least one dynamic vibration absorber (20) provided inside the piston pin (2) to reduce resonance of the piston (1), the piston pin (2), and the small end part (10a) of the connecting rod (10) in combination with respect to the large end part (10b) of the connecting rod (10) during a combustion stroke.

Abstract: A learning assistance server 10 receives, for each question, the answer information indicating the answer to each question in the test questions input to an answer input area 103 on the test screen; updates the test progress information by registering the answer indicated in the received answer information in the test progress information about an appropriate student; and determines with reference to the competitive relationship information whether the student whose test progress information has been updated is linked as the competitor student. When determining that the student is linked as the competitor student, the learning assistance server 10 generates the competitor progress information based on the test progress information about the competitor student.

Abstract: An engine piston structure includes: a piston (1); a connecting rod (10) having a small end part (10a) coupled to the piston (1), and having a large end part (10b) coupled to a crankshaft; a piston pin (2) through which the piston (1) and the small end part (10a) of the connecting rod (10) are coupled together and which has a hollow cross section; and at least one dynamic vibration absorber (20) provided inside the piston pin (2) to reduce resonance of the piston (1), the piston pin (2), and the small end part (10a) of the connecting rod (10) in combination with respect to the large end part (10b) of the connecting rod (10) during a combustion stroke.

Abstract: A learning assistance server 10 receives, for each question, the answer information indicating the answer to each question in the test questions input to an answer input area 103 on the test screen; updates the test progress information by registering the answer indicated in the received answer information in the test progress information about an appropriate student; and determines with reference to the competitive relationship information whether the student whose test progress information has been updated is linked as the competitor student. When determining that the student is linked as the competitor student, the learning assistance server 10 generates the competitor progress information based on the test progress information about the competitor student.

Abstract: A semiconductor device featuring a semiconductor chip including a MOSFET and having a first main surface and a second, opposing main surface, a source electrode pad and a gate electrode pad over the first main surface, a drain electrode over the second main surface, a source external terminal and a gate external terminal, each having a first main surface electrically connected to the source electrode pad and gate electrode pad of the chip, respectively, and a drain external terminal having a first main surface and a second, opposing main surface and being electrically connected to the second main surface of the chip, each of the source, gate and drain external terminals having second main surfaces thereof in a same plane, and, in a plan view of the external terminals, the gate external terminal has a portion located between the source and drain external terminals in at least one direction.

Abstract: This invention provides a retainer assembling apparatus which assembles a retainer to a valve stem via a cotter which engage with an engaging groove formed on the valve stem. The cotter comprises a pair of cotter segments. The apparatus includes a cylindrical body, a holding portion which holds the retainer contacting a lower end of the cylindrical body, a push-up shaft which pushes up the pair of cotter segments into the cylindrical body, and an axial body which is arranged in the cylindrical body to be coaxial with the push-up shaft and to be coaxially movable. The cylindrical body includes a tapered inner circumferential portion on an inner circumferential wall lower portion thereof.

Abstract: A semiconductor device featuring a semiconductor chip including a MOSFET and having a first main surface and a second, opposing main surface, a source electrode pad and a gate electrode pad over the first main surface, a drain electrode over the second main surface, a source external terminal and a gate external terminal, each having a first main surface electrically connected to the source electrode pad and gate electrode pad of the chip, respectively, and a drain external terminal having a first main surface and a second, opposing main surface and being electrically connected to the second main surface of the chip, each of the source, gate and drain external terminals having second main surfaces thereof in a same plane, and, in a plan view of the external terminals, the gate external terminal has a portion located between the source and drain external terminals in at least one direction.

Abstract: A semiconductor device featuring a semiconductor chip having a first main surface and a second, opposing main surface and including a MOSFET having source and gate electrodes formed on the first main surface and a drain electrode thereof formed on the second main surface, first and second conductive members acting as lead terminals for the source and gate electrodes, respectively, are disposed over the first main surface, each of the first and second conductive members has a part overlapped with the chip in a plan view, a sealing body sealing the chip and parts of the first and second conductive members such that a part of the first conductive member is projected outwardly from a first side surface of the sealing body and parts of the first and second conductive members are projected outwardly from the opposing second side surface of the sealing body in a plan view.