CN108691828B - 用于维持最小低侧压力的液压系统或闭路液压系统 - Google Patents
用于维持最小低侧压力的液压系统或闭路液压系统 Download PDFInfo
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
- F15B11/08—Servomotor systems without provision for follow-up action; Circuits therefor with only one servomotor
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/38—Control of exclusively fluid gearing
- F16H61/40—Control of exclusively fluid gearing hydrostatic
- F16H61/4008—Control of circuit pressure
- F16H61/4026—Control of low pressure
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
- F04B49/002—Hydraulic systems to change the pump delivery
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
- F04B49/08—Regulating by delivery pressure
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
- F04B49/22—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00 by means of valves
- F04B49/24—Bypassing
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
- F04B49/22—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00 by means of valves
- F04B49/24—Bypassing
- F04B49/246—Bypassing by keeping open the outlet valve
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
- F15B1/02—Installations or systems with accumulators
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B13/00—Details of servomotor systems ; Valves for servomotor systems
- F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/38—Control of exclusively fluid gearing
- F16H61/40—Control of exclusively fluid gearing hydrostatic
- F16H61/4043—Control of a bypass valve
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/38—Control of exclusively fluid gearing
- F16H61/40—Control of exclusively fluid gearing hydrostatic
- F16H61/4043—Control of a bypass valve
- F16H61/4052—Control of a bypass valve by using a variable restriction, e.g. an orifice valve
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/38—Control of exclusively fluid gearing
- F16H61/40—Control of exclusively fluid gearing hydrostatic
- F16H61/4078—Fluid exchange between hydrostatic circuits and external sources or consumers
- F16H61/4104—Flushing, e.g. by using flushing valves or by connection to exhaust
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/38—Control of exclusively fluid gearing
- F16H61/40—Control of exclusively fluid gearing hydrostatic
- F16H61/4078—Fluid exchange between hydrostatic circuits and external sources or consumers
- F16H61/4139—Replenishing or scavenging pumps, e.g. auxiliary charge pumps
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
- F04B2205/00—Fluid parameters
- F04B2205/16—Opening or closing of a valve in a circuit
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
- F15B2211/205—Systems with pumps
- F15B2211/20507—Type of prime mover
Abstract
液压系统具有通过第一导管和第二导管(即,高侧和低侧)与液压马达,至少一个液压缸或两者连接并连通的液压泵。液压系统具有与第一导管和第二导管连接并与其连通的旁通阀。旁通阀的预设压力大于最小低侧压力。当液压系统发生冲击负载并出现相关的低侧压降时,在压力降低通过预设压力时,旁通阀打开,从而防止压力下降到最小低侧压力。液压系统由此能够在不使用大补给泵或蓄能器的情况下避免导致液压系统的损坏的低回路事件。
Description
相关申请的交叉引用
本申请要求于2017年4月7日提交的美国申请No.62/482,887的权益,该申请通过引用结合于此。
技术领域
本发明涉及一种液压系统,更具体地说是一种利用旁通阀以维持最小低侧压力的闭路液压系统。
背景技术
在闭路中,泵和马达用于将动力从连接到泵轴的动力源传输到连接到马达轴的负载。在闭路系统中,液压流体从泵流向马达,然后从马达直接流回泵,以形成“回路(loop)”。
为了将动力从泵传递给马达,回路一侧的液压流体压力必须高于另一侧。两个压力中较高的一个称为高侧,两个压力中较低的一个称为低侧。补给泵(charge pump)通常用于弥补系统中的泄漏以维持低侧的压力。有时闭路泵直接连接到一个或多个液压缸,液压流体直接从液压缸返回到泵。
通常,在闭路系统中,系统运行时需要维持最小低侧压力。当发生冲击负载时,维持最小低侧压力成为问题,导致陡峭的压力上升率。当发生这种情况时,流体被压缩,导致软管或导管膨胀,并且油被泵入高侧。同时,从马达返回到泵的流体明显减少,由于补给泵无法补偿冲击负载期间所需的流体,这导致低侧的压力降低。此事件通常被称为低回路事件(low loop event),可能会导致泵和马达损坏。
为了解决低侧的波动,已经使用了蓄能器和大补给泵。蓄能器是一个压力容器,其容纳压力下的未压缩流体。尽管有用,但由于服务人员必须具备的技能水平,因此将蓄能器包含在系统中的代价很高且维护成本高。由于流体用尽的问题导致蓄能器不可靠,导致它们无效。
另外或其他,更大的补给泵或超大型补给泵被添加到系统中。由于添加到系统中的热量,这些类型的补给泵效率较低。
因此,改进现有技术是本发明的主要目的。
本发明的另一个目的是防止冲击负载期间的低回路事件。
另一个目标是消除对于蓄能器的需求和消除其他低效率,高成本或用于避免低回路事件所需的高维护元件。
根据说明书和权利要求,本发明的这些和其他目的,特征和优点将变得显而易见。
发明内容
液压系统具有通过第一导管和第二导管(即,高侧和低侧)与液压马达,至少一个液压缸或两者连接并连通的液压泵。液压系统具有与第一导管和第二导管连接并与其连通的旁通阀。旁通阀的预设压力大于最小低侧压力。当液压系统发生冲击负载并出现相关的低侧压降时,在压力降低通过预设压力时,旁通阀打开,从而防止压力下降到最小低侧压力。液压系统由此维持闭路液压系统的最小低侧压力。
液压系统提供与回路冲洗换向阀下游的低侧的恒定连接,并使用此低回路压力作为信号以打开旁通阀,从而如果低侧压力下降超出阈值允许流体从高侧流向低侧。新系统的好处之一就是消除了对蓄能器的需求。因此,该系统的成本较低,部分原因是因为蓄能器价格昂贵,并且往往需要更高水平的服务人员。此外,与具有蓄能器的系统相比,该蓄能器可能流体耗尽且变得无效,该系统每次都更可靠。
另一个好处是液压系统消除了对大型或超大型补给泵的需求。虽然有时可用于解决低回路事件的问题,但这些补给泵效率较低。
附图说明
图1是用于维持闭路液压系统的最小低侧压力的液压系统的示意图;
图2是用于维持闭路液压系统的最小低侧压力的液压系统的旁通阀开放面积与低压的曲线图;
图3A和3B是用于维持闭路液压系统的最小低侧压力的液压系统上的冲击负载的曲线图;
图4A和4B是用于维持闭路液压系统的最小低侧压力的液压系统的冲击负载的曲线图;和
图5是用于维持闭路液压系统的最小低侧压力的流过液压系统的旁通阀的流量的曲线图。
具体实施方式
参考附图,液压系统10包括由常规发动机或原动机(未示出)驱动的液压泵12。在一个实施例中,液压泵12是可变排量液压泵12。液压泵12通过第一导管16和第二导管18连接到液压马达14并与液压马达14连通,以形成闭路19。这两者是可互换的,为了示例性目的,第一导管16将被称为指示高侧16a并且第二导管18将被称为低侧18a。在一些实施例中,液压泵12连接到至少一个液压缸(未示出)以代替液压马达14或除了液压马达14之外,液压泵12还连接到至少一个液压缸,以形成闭路19。
固定排量补给泵或补给泵20被连接到液压泵12并在运行期间补充在闭路19中发生的流体损失。补给压力释放阀22建立补给压力23(未示出),补给泵20以补给压力23将流体输送到闭路19的低侧18a。其他常规项目,例如压力限制阀,高压释放阀,用于控制泵和马达的排量的阀,以及过滤器被包括在系统10中,但是这些项目在本领域中是公知的,并且与本发明并不特别相关。
连接在高侧16a和低侧18a之间并与其连通的是回路冲洗系统(loop flushingsystem)24。回路冲洗系统24可以是任何类型的,并且可以在液压泵12或液压马达14的内部或在位于液压泵12和液压马达14之间的任何地方的单独的阀中。在所示的例子中,回路冲洗系统24包括换向阀(shuttle valve)26和释放阀28。还连接到高侧16a和低侧18a且与高侧16a和低侧18a连通的且与回路冲洗系统24平行的是旁通阀30。在打开或移位时,旁通阀30将流体从高侧16a输送到低侧18a。当旁通阀30直接位于回路冲洗系统24的下游时,这是特别有效的。
旁通阀30具有高于最小低侧压力34的预设压力32。最小低侧压力34等于或刚好高于低回路事件36的阈值。在一个实施例中,当低侧18a中的流体压力等于或低于预设压力32时,旁通阀30完全打开。这种布置被称为快速打开38。
可选地,当低侧18a中的流体压力等于或低于预设压力32时,旁通阀30部分地打开。随着低侧18a上的压力降低并且逐渐打开,旁通阀30继续打开,并且在整个降压过程中被逐渐打开或在等于或低于最小低侧压力34时立即打开。这些布置被称为慢速打开40。在一种布置中,慢速打开40通过增加旁通阀30的弹簧腔室孔41而实现。
尽管快速打开38和慢速打开40都阻止低回路事件36,但两者不同。如图5所示,快速打开38导致更多流体进入低侧18a。如图4B所示,慢速打开40导致系统10中更平滑的过渡。快速打开38和慢速打开40都不需要包括蓄能器,大补给泵和超大补给泵(未示出)。
图2-5中描绘了系统10的示例。通过使用标准马达负载,约0.5-2kg/m2的惯性,通过模拟3,000-5,000psi/秒的冲击负载40来对示例性系统10进行测试,并且回路冲洗系统24是“中性打开”类型。液压泵12的速度是1800rpm。旁通阀30的预设压力32为15巴,最小低侧压力34为10巴。这些例子示出了系统10以图2所示的快速打开38和慢速打开40进行操作。图3A-4B还示出了系统10在没有旁通阀30的情况下的操作。
图2-5显示了在约2秒处发生的冲击负载42。如图3B所示,由于流体从高侧16a流向低侧18a,所以旁通阀30的存在延迟了冲击负载42的全部效果。
同时,图4A和4B示出不存在旁通阀30导致低侧18a中的压力急剧下降,其该低侧18a中的压力低于10巴的最小低侧压力34,即低回路事件36。
相反,图4A和4B示出了当存在旁通阀30时,来自冲击负载42的低回路事件36不会发生。取而代之的是,当压力下降到15巴或更低时(即预压力32),旁通阀30打开,从而防止由低于或等于10巴(即最小低侧压力34)的压力而导致的低压回路。
从上面的讨论和附图以及权利要求中,可以理解,液压系统10相对于现有技术具有很多优点。本领域技术人员将进一步理解,可以对设备进行其他各种修改而不偏离本发明的精神和范围。所有这些修改和变化都在权利要求的范围内,并且因此被涵盖。应该理解,这里描述的示例和实施例仅用于说明的目的,并且对于本领域技术人员将暗示其各种修改或变化,并且将被包括在本申请的精神和范围内。
Claims (9)
1.一种液压系统,其包括:
液压泵,其通过作为高压侧的第一导管和作为低压侧的第二导管与液压马达和液压缸中的至少一个连接并连通;
旁通阀,其连接在第一导管和第二导管之间并与第一导管和第二导管连通;
所述旁通阀具有高于最小低压侧压力的预设压力,其中所述旁通阀配置为在所述第二导管的压力低于所述预设压力时打开,以及
最小低压侧压力近似等于发生低回路事件的阈值,低回路事件是液压系统的低压侧压力降低而小于用于液压系统正常运行的最小正常运行低压侧压力。
2.根据权利要求1所述的液压系统,其中,所述旁通阀被构造成快速打开。
3.根据权利要求1所述的液压系统,其中,所述旁通阀被构造成慢速打开。
4.根据权利要求1所述的液压系统,还包括连接在所述第一导管和所述第二导管之间并与所述第一导管和所述第二导管连通的回路冲洗系统。
5.如权利要求4所述的液压系统,其中,所述旁通阀直接位于所述回路冲洗系统的下游并与其平行。
6.根据权利要求1所述的液压系统,其中,当所述旁通阀打开时,高压流体从所述第一导管移至所述第二导管。
7.根据权利要求1所述的液压系统,其中,没有蓄压器与所述第一导管或所述第二导管连通。
8.根据权利要求1所述的液压系统,其中,所述旁通阀被配置为延迟冲击负载的影响。
9.根据权利要求1所述的液压系统,其中,当所述旁通阀打开时,防止所述第二导管的压力低于最小低压侧压力。
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DE102018205194B4 (de) | 2023-07-06 |
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