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Review Article

A Review of Direct Drive Proportional Electrohydraulic Spool Valves: Industrial State-of-the-Art and Research Advancements

[+] Author and Article Information
Paolo Tamburrano

Department of Mechanics,
Mathematics and Management (DMMM),
Polytechnic University of Bari,
Via Orabona 4,
Bari 70125, Italy;
Centre for Power Transmission and
Motion Control (PTMC),
Department of Mechanical Engineering,
University of Bath,
Claverton Down,
Bath BA2 7AY, UK
e-mails: paolo.tamburrano@poliba.it;
P.Tamburrano@bath.ac.uk

Andrew R. Plummer

Centre for Power Transmission and
Motion Control (PTMC),
Department of Mechanical Engineering,
University of Bath,
Claverton Down,
Bath BA2 7AY, UK
e-mail: A.R.Plummer@bath.ac.uk

Elia Distaso

Department of Mechanics,
Mathematics and Management (DMMM),
Polytechnic University of Bari,
Via Orabona 4,
Bari 70125, Italy
e-mail: elia.distaso@poliba.it

Riccardo Amirante

Department of Mechanics,
Mathematics and Management (DMMM),
Polytechnic University of Bari,
Via Orabona 4,
Bari 70125, Italy
e-mail: riccardo.amirante@poliba.it

1Corresponding author.

Contributed by the Dynamic Systems Division of ASME for publication in the JOURNAL OF DYNAMIC SYSTEMS, MEASUREMENT,AND CONTROL. Manuscript received February 26, 2018; final manuscript received July 28, 2018; published online October 5, 2018. Assoc. Editor: Heikki Handroos.

J. Dyn. Sys., Meas., Control 141(2), 020801 (Oct 05, 2018) (16 pages) Paper No: DS-18-1095; doi: 10.1115/1.4041063 History: Received February 26, 2018; Revised July 28, 2018

This paper reviews the state of the art of directly driven proportional directional hydraulic spool valves, which are widely used hydraulic components in the industrial and transportation sectors. First, the construction and performance of commercially available units are discussed, together with simple models of the main characteristics. The review of published research focuses on two key areas: investigations that analyze and optimize valves from a fluid dynamic point of view, and then studies on spool position control systems. Mathematical modeling is a very active area of research, including computational fluid dynamics (CFD) for spool geometry optimization, and dynamic spool actuation and motion modeling to inform controller design. Drawbacks and advantages of new designs and concepts are described in the paper.

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Figures

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Fig. 1

Proportional valve ATOS-DKZOR-T [28]: 1—valve body, 2—spool, 3—solenoid, 4—LVDT, 5—electronic control, 6 and 7—connectors)

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Fig. 2

Metering curve as a function of the pressure drop for a given opening degree

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Fig. 3

Typical control system of a proportional valve (Adapted from Ref. [20])

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Fig. 4

Section view of a 4/3 proportional valve (a) and enlargement on the spool surface with velocity and force vectors (b)

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Fig. 5

Operational field of two commercially available valves: DKZOR-AES (external line) and DHZO-AES (internal line)2

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Fig. 6

Reproduction of the Bode plot of the proportional valve 4WREE size 10, produced by Bosch Rexroth4

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Fig. 7

Reproduction of the step test diagram of the proportional valve 4WREE size 10, produced by Bosch Rexroth4

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Fig. 8

The three notch typologies analyzed in Ref. [28]

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Fig. 9

Experimental circuits employed in [28]: (a), [30]: (b), [46]: (c), [48]: (d), [10]: (e), and [23]: (f)

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Fig. 10

Qualitative trend of the discharge coefficient versus Reynolds number for a fixed notch geometry [28,46]

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Fig. 11

Flow rate through a fixed orifice as a function of the square root of the pressure drop (Δp) and upstream pressure (p1) [30]

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Fig. 12

Experimental apparatus to evaluate the actuation forces: 1—coil, 2—LVDT, 3—load cell, 4—micrometer screw, and 5—armature [32]

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Fig. 13

Electromagnetic force as a function of the armature position and current intensity

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Fig. 14

Experimental apparatus for measuring the actuation force that is based on a screw mechanism coupled with a force sensor

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Fig. 15

Geometric characteristics of (a) the spheroid-shape groove, (b) the triangle-shape groove, and (c) the divergent U-shape groove, analyzed in Ref. [46]

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Fig. 16

Left: partial 3D CFD model employed in Ref. [46]; right: pressure contours on the symmetry plane: (a) X = 0.6 mm, (b) X = 1.4 mm, and (c) X = 2.0 mm [46]

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Fig. 17

Values of the jet flow angle according to different notch profiles obtained via CFD [46]

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Fig. 18

Full 3D grid developed in Ref. [33]

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Fig. 19

Full 3D grid used in Ref. [10] (a), metering curves obtained numerically and experimentally for low and high discharge pressure with an overall pressure drop = 70 bar (b), and contours of volume fraction on the spool surface (c)

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Fig. 20

Design parameters adopted for the fluid dynamic optimization performed in Ref. [11] and experimentally validated in Ref. [23]: comparison between reference geometry and optimized one

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Fig. 21

Contours of pressure in the novel valve body geometry presented in Ref. [33]: 2 and 3 denote the additional channels

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Fig. 22

Peak and hold technique employed in Ref. [21]

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