Swivel control apparatus

{
  "publication_number": "US6339929B1",
  "country": "US",
  "kind": "B1",
  "title": "Swivel control apparatus",
  "abstract": "A swivel control apparatus according to the present invention, includes: a hydraulic pump; a hydraulic motor for swiveling which is driven by hydraulic oil emitted from the hydraulic pump; a control valve which controls a flow of hydraulic oil which is supplied from the hydraulic pump to the hydraulic motor for swiveling, and at a neutral position of the control valve cuts off from one another a pair of ports which communicate to input and output ports of the hydraulic motor; a valve device which communicates and cuts off from one another a pair of conduits which are respectively connected to the input and output ports of the hydraulic motor for swiveling; a pressure detection device which detects respective pressures in the two conduits and outputs pressure signals; a rotational speed detection device which detects a physical quantity based upon a rotational speed of the hydraulic motor for swiveling and outputs a rotational speed signal; a mode selection device which selects a neutral brake mode and a neutral free mode; and a control device which controls driving of the valve device so as to cut off the two conduits from one another when the neutral brake mode is selected, and so as to communicate the two conduits based upon the pressure signals and the rotational speed signal when the neutral free mode is selected.",
  "claims": [
    "1. A swivel control apparatus, comprising: a hydraulic pump; a hydraulic motor for swiveling which is driven by hydraulic oil emitted from said hydraulic pump; a control valve which controls a flow of hydraulic oil which is supplied from said hydraulic pump to said hydraulic motor for swiveling, and at a neutral position of the control valve cuts off from one another a pair of ports which communicate to input and output ports of said hydraulic motor; a valve device which communicates and cuts off from one another a pair of conduits which are respectively connected to the input and output ports of said hydraulic motor for swiveling; a pressure detection device which detects respective pressures in said two conduits and outputs pressure signals; a rotational speed detection device which detects a physical quantity based upon a rotational speed of said hydraulic motor for swiveling and outputs a rotational speed signal; a mode selection device which selects a neutral brake mode and a neutral free mode; and a control device which controls driving of said valve device so as to cut off said two conduits from one another when said neutral brake mode is selected, and so as to communicate said two conduits based upon said pressure signals and said rotational speed signal when said neutral free mode is selected.",
    "2. A swivel control apparatus according to claim 1, wherein said control device calculates a direction of action of hydraulic oil upon said hydraulic motor based upon said pressure signals, calculates a rotational direction of said hydraulic motor based upon said rotational speed signal, and controls the driving of said valve device so as to communicate said two conduits when said neutral free mode is selected and a calculated direction of action of hydraulic oil upon said hydraulic motor and the rotational direction of said hydraulic motor are different.",
    "3. A swivel control apparatus according to claim 2, wherein said control device calculates a target flow amount based upon said rotational speed signal, and controls the driving of said valve device so that said target flow amount flows from one of said conduits to the other of said conduits.",
    "4. A swivel control apparatus according to claim 3, further comprising a deceleration ratio setting device which sets a deceleration ratio for said hydraulic motor for swiveling, wherein said control device calculates said target flow amount based upon a set value from said deceleration ratio setting device.",
    "5. A swivel control apparatus according to claim 3, wherein said control device controls the driving of said valve device based upon a conversion table that is predetermined to obtain a value of a control signal for said valve device based upon said target flow amount.",
    "6. A swivel control apparatus according to claim 3, wherein said target flow amount is assumed as a value for a flow amount passing through an orifice, a differential pressure between said two conduits detected by said pressure detection device is assumed as a value for a differential pressure of orifice said control device calculates an opening amount of orifice by substituting the assumed values into an equation based upon the orifice equation, and controls the driving of said valve device based upon a control signal corresponding to the calculated opening amount of orifice.",
    "7. A swivel control apparatus according to claim 1, wherein said valve device is an electromagnetic proportional valve and is controlled so as to be closed when said neutral brake mode is selected and so as to be opened with a predetermined opening area when said neutral free mode is selected.",
    "8. A hydraulic swiveling type of crane comprising: a traveling body; a swiveling body that is mounted upon said traveling body to be able to swing; and a swivel control apparatus that controls swiveling of said swiveling body, wherein said swivel control apparatus comprises: a hydraulic pump; a hydraulic motor for swiveling which is driven by hydraulic oil emitted from said hydraulic pump; a control valve which controls a flow of hydraulic oil which is supplied from said hydraulic pump to said hydraulic motor for swiveling, and at a neutral position of the control valve cuts off from one another a pair of ports which communicate to input and output ports of said hydraulic motor; a valve device which communicates and cuts off from one another a pair of conduits which are respectively connected to the input and output ports of said hydraulic motor for swiveling; a pressure detection device which detects respective pressures in said two conduits and outputs pressure signals; a rotational speed detection device which detects a physical quantity based upon a rotational speed of said hydraulic motor for swiveling and outputs a rotational speed signal; a mode selection device which selects a neutral brake mode and a neutral free mode; and a control device which controls driving of said valve device so as to cut off said two conduits from one another when said neutral brake mode is selected, and so as to communicate said two conduits based upon said pressure signals and said rotational speed signal when said neutral free mode is selected."
  ],
  "description_excerpt": "This application is a continuation of PCT Application No. PCT/JP99/06606 filed on Nov. 26, 1999. This application is based upon Japanese Patent Application No. 337559 of Heisei 10, filed Nov. 27, 1998, and its contents are incorporated herein by reference.\n\nThe present invention relates to a swivel control apparatus for a construction machine such as a crane or the like.\n\nIn a control system for swiveling, in the past, there is a mode (termed the “neutral free mode”) in which the motor is rotated by the inertia of the swiveling body when the operating lever has been returned to neutral; and there is a mode (termed the “neutral brake mode”) in which the rotation of the motor is stopped when the operating lever has been returned to neutral. It is desirable for the use of these modes to be separated according to the nature of the job, and for example in Japanese Patent Publication Serial No. 2,549,420 there is disclosed an apparatus with which either of these modes can be selected with one machine. With the apparatus of this publication, respective relief valves are provided to conduits connected to the input and output ports of the hydraulic motor, and a relationship between the amount of actuation of the operating lever and the relief pressures of the relief valves are made into patterns and established in advance for each of the neutral free and neutral brake modes. It is possible to control the driving of the swiveling body in correspondence with each of the neutral free/neutral brake modes by controlling the relief valves in accordance with these characteristics (patterns) of relief pressure.",
  "cpc": [
    "E02F 9/2285",
    "B66C 23/86",
    "E02F 9/123",
    "E02F 9/128",
    "F15B 11/00",
    "F15B 11/024",
    "F15B 21/087",
    "F15B 2211/20515",
    "F15B 2211/30505",
    "F15B 2211/30525",
    "F15B 2211/3058",
    "F15B 2211/3116",
    "F15B 2211/31576",
    "F15B 2211/329",
    "F15B 2211/40515",
    "F15B 2211/41536",
    "F15B 2211/426",
    "F15B 2211/50518",
    "F15B 2211/55",
    "F15B 2211/6313",
    "F15B 2211/6336",
    "F15B 2211/6654",
    "F15B 2211/6656",
    "F15B 2211/7058",
    "F15B 2211/75"
  ],
  "ipc": [
    "B66C 23/84",
    "B66C 23/86",
    "E02F 9/12",
    "E02F 9/22",
    "F15B 11/00",
    "F15B 11/024",
    "F15B 21/08"
  ],
  "assignees": [
    "HITACHI CONSTRUCTION MACHINERY"
  ],
  "inventors": [
    "UDAGAWA TSUTOMU",
    "IGARASHI TERUO",
    "OCHIAI MASAMI",
    "SAKAI TOSHIMI",
    "ISHIDA KAZUHISA",
    "FUNATO KOUJI"
  ],
  "filing_date": "2000-07-25",
  "publication_date": "2002-01-22",
  "grant_date": "2002-01-22",
  "priority_date": "1998-11-27",
  "application_number": "US-62541600-A",
  "family_id": "18309791",
  "citations": [
    "DE4410976A1",
    "JP2547441B2",
    "JP2549420Y2",
    "JPH0276907A",
    "JPH06280814A",
    "JPH0741002U",
    "JPH10110703A",
    "JPH10246205A",
    "JPS5841127A",
    "JPS61112068A",
    "US4194365A",
    "US4586332A",
    "US5046312A",
    "US5159813A",
    "US5285643A",
    "US5419132A",
    "US5709083A"
  ]
}