Abstract: Provided is a speed reducer including: a first reduction unit disposed at an input stage of a multi-stage reduction unit that decelerates a rotational driving force of an electric motor from an input stage side toward an output stage side and transmits the decelerated rotational driving force to a rotational drive unit; a first ring gear meshed with first planetary gears provided in the first reduction unit; and a third reduction unit disposed at an output stage of the multi-stage reduction unit and having a first case. The first ring gear is provided in the first case of the third reduction unit.

Abstract: A speed reducer according to one aspect of the present disclosure includes: speed reducing units for decelerating a rotational driving force of an electric motor and transmitting the decelerated rotational driving force to a rotational driving unit; and a ring gear meshing with a gear decelerated by a speed reducing unit on the electric motor side in a direction of a rotational axis of the electric motor. The ring gear is provided with a water-cooling channel that communicates cooling water. The water-cooling channel includes a first groove having a small depth and a second groove having a larger depth and extends in a C-shape as the ring gear is viewed from the direction of the rotational axis. The ring gear is provided with a motor flange mounted to the electric motor. The motor flange is provided with an inlet port and an outlet port connected to the water-cooling channel.

Abstract: A crawler drive unit relating to one aspect of the present disclosure includes a speed reduction mechanism provided in a running unit for causing a vehicle body to run, where the speed reduction mechanism is configured to transmit a driving force to a crawler provided on the running unit, a transmission mechanism for transmitting the driving force to the speed reduction mechanism, and an electric motor for applying a rotational force to the transmission mechanism. A motor shaft of the electric motor is positioned higher than a rotational axis of an input shaft of the speed reduction mechanism.

Abstract: Provided is a speed reducer including: a first reduction unit disposed at an input stage of a multi-stage reduction unit that decelerates a rotational driving force of an electric motor from an input stage side toward an output stage side and transmits the decelerated rotational driving force to a rotational drive unit; a first ring gear meshed with first planetary gears provided in the first reduction unit; and a third reduction unit disposed at an output stage of the multi-stage reduction unit and having a first case. The first ring gear is provided in the first case of the third reduction unit.

Abstract: The present invention provides a packet communication system including a mobile host, a home agent, a correspondent host, and a mobility agent, where the mobility agent operates in such a way that when the mobile host is in an active mode and has no need for buffering packets, the mobility agent forwards packets received from the home agent or the correspondent host to the mobile host; and alternatively, in the case when the mobile host is in an active mode, but requires buffering of packets, the mobility agent buffers the packets, and further in the case when the mobile host is in an idle mode, the mobility agent buffers the packet and notifies the mobile host of arrival of the packet, in order to prevent the loss of a packet addressed to a mobile host thus decreasing the traffic and the transmission frequency of Binding Update packets.

Abstract: There is disclosed a link manager comprises detecting unit for detecting what link is installed; managing unit for defining a plurality of link metrics indicating characteristics of each link detected and managing data corresponding to the respective link metrics on a table; and selecting unit for selecting a link having link metrics complying with a given condition.

Abstract: A packet communication method of performing communication employing a packet having a transmission-source address and destination address, comprises the steps of: making a predetermined number of bits of the transmission-source address and a predetermined number of bits of destination address be fixed addresses; a repeating node for repeating a packet from a transmission-source terminal first converting the fixed address of the transmission-source address of the received packet into an address of an higher-rank station of the repeating node; and the repeating address converting the fixed address of the destination address of the received packet into an address of an higher-rank station of a last repeating node for a destination terminal, and transferring the packet.

Abstract: A location managing method for managing a location of a mobile station in a mobile wireless packet communication system in which each of communication nodes down to a base station have a hierarchical structure, wherein a route from a communication node positioned at a highest layer of the hierarchical structure to a base station of a cell in which a mobile station is located, is managed as location information of the mobile station, by being distributed to the communication node located at the highest layer of the hierarchical structure and to each of communication nodes in the route to the base station.

Abstract: The present invention provides a packet communication system has a mobile host, a home agent, a correspondent host, and a mobility agent, wherein the mobility agent operates in such a way that in the case of an active mode and no need for buffering of packet, the mobility agent forwards a packet received from the home agent or the correspondent host, to the mobile host, that in the case of the active mode and necessity for buffering of packet, the mobility agent buffers the packet, and that in the case of an idle mode, the mobility agent buffers the packet and notifies the mobile host of arrival of the packet, in order to prevent the loss of a packet addressed to a mobile host, to decrease the traffic of Binding Update packets, to decrease the transmission frequency of Binding Update packets where the mobile host sends or receives no packet for a long period of time, and to send a packet a destination of which is a node present at a mobile network.

Abstract: A method for providing information, a mobile communication system and a communication apparatus are provided with high reliability of providing information to mobile terminals. The router transfers the information packets obtained from the Internet to all of the access points. Each of the access points transmits those information packets to a service area of its own provided by the access point. Therefore, the mobile terminal located in the service area provided by any of the access points can receive the information packets, thereby the reliability of providing information to the mobile terminals is improved.

Abstract: There is disclosed a link manager comprises detecting unit for detecting what link is installed; managing unit for defining a plurality of link metrics indicating characteristics of each link detected and managing data corresponding to the respective link metrics on a table; and selecting unit for selecting a link having link metrics complying with a given condition.

Abstract: A location managing method for managing a location of a mobile station in a mobile wireless packet communication system in which each of communication nodes down to a base station have a hierarchical structure, wherein a route from a communication node positioned at a highest layer of the hierarchical structure to a base station of a cell in which a mobile station is located, is managed as location information of the mobile station, by being distributed to the communication node located at the highest layer of the hierarchical structure and to each of communication nodes in the route to the base station.

Abstract: A packet communication method of performing communication employing a packet having a transmission-source address and destination address, comprises the steps of: making a predetermined number of bits of the transmission-source address and a predetermined number of bits of destination address be fixed addresses; a repeating node for repeating a packet from a transmission-source terminal first converting the fixed address of the transmission-source address of the received packet into an address of an higher-rank station of the repeating node; and the repeating address converting the fixed address of the destination address of the received packet into an address of an higher-rank station of a last repeating node for a destination terminal, and transferring the packet.