GB2257270A - Hydraulic switching system - Google Patents
Hydraulic switching system Download PDFInfo
- Publication number
- GB2257270A GB2257270A GB9213679A GB9213679A GB2257270A GB 2257270 A GB2257270 A GB 2257270A GB 9213679 A GB9213679 A GB 9213679A GB 9213679 A GB9213679 A GB 9213679A GB 2257270 A GB2257270 A GB 2257270A
- Authority
- GB
- United Kingdom
- Prior art keywords
- valve
- pressure
- pressure relief
- relief valve
- directional control
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- 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
- F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
- F15B13/042—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure
- F15B13/0422—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure with manually-operated pilot valves, e.g. joysticks
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Fluid-Pressure Circuits (AREA)
Description
2257270 A Hvdraulic switchinq svstem
The invention relates to a hydraulic switching system for regulating the direction of travel, speed and moment of a consumption unit according to the preamble of Claim 1.
A hydraulic switching system of this kind is known by virtue of DE 23 04 334 C2. In the case of the known control valve, the speed of a hydraulic consumption unit is regulated in proportion to a preliminary control signal of the hydraulic valve as a function of the set flow cross-section. The pressure relationship between the pump pressure and the load pressure is regulated, by means of a three-way pressure balance, to a value which is pre-set by a spring. A control system of this kind is always expedient whenever varying loads can be expected in the operation of the consumption unit.
The object of the invention is to construct the hydraulic control system from simple structural partst yet such that it can at the same time be regulated in a highly sensitive manner, to be precise for consumption units having pre-determinable. essentially constant loads. Such loads enter into consideration, for example, in the case of hydraulically actuated rotary drive systems.
The achievement of the object derives from the characterising part of Claim 1.
The advantage consists in the fact that the directional control valve is very simply constructed. that the control system of the pressure relief valve relates only to one control direction of this valve and that. in addition, the pump output can be finely tuned to the requirements of the consumption unit.
A throttle valve suitable for this purpose is known, for examplei from EPO 179 249 A2.
The invention is explained below with reference to the appended single figure, which shows the hydraulic switching system of an illustrative embodiment.
The consumption unit 1 can be operated in both working directions. e.g. left-running or right-running. For this purpose. the consumption unit 1 is connected to the hydraulic pump 2 and to the pump line 3 via a controllable current-regulating valve 4 and a directional valve 5. The current-regulating valve 4 can be hydrau- lically closed or set to a throttled throughput. The directional valve 5 is a 3/2 directional control valve, which can be hydraulically regulated into one of the two directional settings. The pump line 3 is connected, between the current-regulating valve 4 and the direc- tional valve 5, to a hydraulically controllable pressure relief valve 6. The pressure relief valve 6 can be set by hydraulic adjustment of its spring. The pump line 3 is connected, via the controllable pressure relief valve 6, to the return circuit or to the tank 7.
The pump line is additionally levelled by the main step of the pressure relief valve 8 to the pressure pre-set by the preliminary control step of the pressure relief valve 6. For this purpose. the pressure of the pump line 3 is placed upon the one side of the main step of the pressure relief valve 8 and the pressure which has been reduced by a measuring throttle 9 is placed upon the spring side of the pressure relief valve 8. The pressure relief valve 8 is connected. at the outlet. to the tank 7. The measuring throttle 9 is disposed in the connection between the pump line 3 and the preliminary control step of the pressure relief valve 6.
The regulation _is served by a prel i Mi nary control unit 10, which is manually operated by an actuating lever 11. The preliminary control unit 10 is supplied with compressed oil by a control pump 12. The two control pressure lines of the preliminary control unit 10 are connected on the one hand to the two sides of the directional valve 5, so that the one or the other side can be favoured, as desired. The left/right running of the consumption unit 1 is thereby regulated. In addition, the control pressure lines are connected via a shuttle valve 13 to the hydraulic adjusting mechanism 14 of the pre- liminary control step of the pressure relief valve 6 and to the hydraulic adjusting mechanism 16 of the currentregulating valve 4.
It is worth mentioning that, in place of a hydraulic preliminary control unit 10, an electrically controlled command value transmitter can be used. Where this is used. the mechanical changes of setting on the actuating lever 11 are converted into analog electric signals, which are led via electrical control lines - in particular. in the case of a remote control system. over a considerable distance - to electric /electromagnetic actuating members, and which combine with electrohydraulic signal converters to produce once again hydraulic signals, which then act upon the directional valve 5 and. via the shuttle valve 13. upon the hydraulic adjusting mechanisms 14 and 15.
Regarding the functioning: by virtue of the right/left movement of the actuating lever 11, the direction valve 5.. firstly, is actuated in the one or the other direction. If the actuating lever 11 is further deflected, the control pressure is predetermined by means of shuttle valves 13, on the one hand of the preliminary control system 15 of the current-regulating valve 4 and on the other hand of the preliminary control system 14 of the adjustable pressure relief valve 6. As a result of the control-pressure-dependent setting of the currentregulating valve 4. the supply to the consumption unit 1 can be set to the requirement corresponding to the particular control pressure level. Additionally. by virtue of the control pressure level. the pressure in the pump line 3 is predetermined, as desired, via the hydraulic preliminary control valve 14, and this value is levelled by the main step of the pressure relief valve 8. The level of the control pressure enables the drive - 4 moment to be set by adjustment of the pressure in the pump line 3, and the currentregulating valve 41 which, where necessary, is connected upstream, enables the speed of the consumption unit 1 to be set.
IP-1924 1 3 4 6 7 8 9 11 12 13 14 REFERENCE SYMBOL LISTING consumption unit hydraulic pump pump line current-regulating valve directional valve pressure relief valve (preliminary control step) tank pressure relief valve (main step) measuring throttle preliminary control unit actuating lever control pump shuttle valve hydraulic adjusting mechanism hydraulic adjusting mechanism IP-1924
Claims (4)
1. Hydraulic switching system f or regulating the direction of travel, speed and drive moment of a consumption unit (1). having a directional control valve (5) via which the consumption unit (1) can be connected to the hydraulic pump (2) and to the return circuit to the tank (7), and having a pressure relief valve (6, 8)f by which the pump line (3) in front of the directional control valve (5) can be connected to the return circuit to the tank (7),, wherein the regulating f orce of the pressure relief valve (6) can be hydraulically regulated on a continuous scale.
2. Control system according to Claim 1, wherein the directional control valve (5) can only either be closed in a twin-setting operation or opened to maximum crosssection.
3. Control system according to Claim 1 or 2, wherein the directional control valve (5) is a 3/2 directional control valve, which is hydraulically regulated and is connected to two lines conveying an adjustable pressure, and wherein the pressure relief valve (6) is connected to these pressure lines via a shuttle valve (13).
4. Control system according to one of the preceding 25 claims, wherein, into the pipe system connecting the pump line (3) to the pressure relief valve (6), there is interposed a measuring throttle (9), the pressure differential of which is placed upon a pressure balance (8) connecting the pump line (3) to the tank (7).
3
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4121235 | 1991-06-27 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9213679D0 GB9213679D0 (en) | 1992-08-12 |
| GB2257270A true GB2257270A (en) | 1993-01-06 |
| GB2257270B GB2257270B (en) | 1995-08-30 |
Family
ID=6434866
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9213679A Expired - Fee Related GB2257270B (en) | 1991-06-27 | 1992-06-26 | Hydraulic switching system |
Country Status (4)
| Country | Link |
|---|---|
| DE (1) | DE4220656A1 (en) |
| FR (1) | FR2678323B1 (en) |
| GB (1) | GB2257270B (en) |
| IT (1) | IT1255170B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06173904A (en) * | 1992-12-08 | 1994-06-21 | Komatsu Ltd | Rotary hydraulic circuit |
| DE19833489A1 (en) | 1998-07-24 | 2000-01-27 | Mannesmann Rexroth Ag | Hydraulic circuit for controlling user of work apparatus has pump supplying user with pressure medium via feed conduit with back flow conduit feeding back to tank |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB814618A (en) * | 1955-04-29 | 1959-06-10 | New York Air Brake Co | Hydraulic control systems more particularly for bulldozers and the like |
| GB1369664A (en) * | 1970-09-11 | 1974-10-09 | Koppen Lethem Trading | Devices for limitting pressure in a hydraulic circuit |
| GB2013841A (en) * | 1978-01-30 | 1979-08-15 | Caterpillar Tractor Co | Work fluid system |
| WO1986004963A1 (en) * | 1985-02-23 | 1986-08-28 | Barmag Barmer Maschinenfabrik Aktiengesellschaft | Proportional valve with variable pre-loading of the balance spring non-proportionally to the load pressure |
| EP0462590B1 (en) * | 1990-06-19 | 1995-12-27 | Hitachi Construction Machinery Co., Ltd. | Hydraulic drive system for civil-engineering and construction machine |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3646959A (en) * | 1970-10-12 | 1972-03-07 | Sperry Rand Corp | Power transmission |
| JPS5663102A (en) * | 1979-10-29 | 1981-05-29 | Kobe Steel Ltd | Turning oil-pressure circuit for oil-pressure shovel, etc. |
| JPS60249706A (en) * | 1984-05-22 | 1985-12-10 | Toshiba Mach Co Ltd | Hydraulic control device |
| JPS612908A (en) * | 1984-06-14 | 1986-01-08 | Toshiba Mach Co Ltd | Control valve device |
| JPH076525B2 (en) * | 1987-01-09 | 1995-01-30 | 株式会社神戸製鋼所 | Swing hydraulic circuit of construction machinery |
-
1992
- 1992-06-24 DE DE4220656A patent/DE4220656A1/en not_active Withdrawn
- 1992-06-24 IT ITMI921550A patent/IT1255170B/en active IP Right Grant
- 1992-06-26 GB GB9213679A patent/GB2257270B/en not_active Expired - Fee Related
- 1992-06-26 FR FR9207922A patent/FR2678323B1/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB814618A (en) * | 1955-04-29 | 1959-06-10 | New York Air Brake Co | Hydraulic control systems more particularly for bulldozers and the like |
| GB1369664A (en) * | 1970-09-11 | 1974-10-09 | Koppen Lethem Trading | Devices for limitting pressure in a hydraulic circuit |
| GB2013841A (en) * | 1978-01-30 | 1979-08-15 | Caterpillar Tractor Co | Work fluid system |
| WO1986004963A1 (en) * | 1985-02-23 | 1986-08-28 | Barmag Barmer Maschinenfabrik Aktiengesellschaft | Proportional valve with variable pre-loading of the balance spring non-proportionally to the load pressure |
| US4794846A (en) * | 1985-02-23 | 1989-01-03 | Barmag Ag | Proportional action valve with a biased spring unproportionately variable to the load pressure |
| EP0462590B1 (en) * | 1990-06-19 | 1995-12-27 | Hitachi Construction Machinery Co., Ltd. | Hydraulic drive system for civil-engineering and construction machine |
Also Published As
| Publication number | Publication date |
|---|---|
| ITMI921550A1 (en) | 1993-12-24 |
| GB2257270B (en) | 1995-08-30 |
| GB9213679D0 (en) | 1992-08-12 |
| IT1255170B (en) | 1995-10-20 |
| DE4220656A1 (en) | 1993-01-07 |
| FR2678323A1 (en) | 1992-12-31 |
| FR2678323B1 (en) | 1996-02-16 |
| ITMI921550A0 (en) | 1992-06-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19990626 |