Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25F—COMBINATION OR MULTI-PURPOSE TOOLS NOT OTHERWISE PROVIDED FOR; DETAILS OR COMPONENTS OF PORTABLE POWER-DRIVEN TOOLS NOT PARTICULARLY RELATED TO THE OPERATIONS PERFORMED AND NOT OTHERWISE PROVIDED FOR
  • B25F5/00—Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for
  • B25F5/005—Hydraulic driving means
• • 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
  • F04B11/00—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation
  • F04B11/0008—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation using accumulators
  • F04B11/0033—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation using accumulators with a mechanical spring
• • 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
  • F04B49/02—Stopping, starting, unloading or idling control
  • F04B49/03—Stopping, starting, unloading or idling control by means of valves
• • 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

Definitions

• the present invention relates to a hydraulic tool and in particular a hydraulic drive unit for such a hydraulic tool according to the preamble of claim 1.
• Such a hydraulic drive unit is known from the unpublished (same applicant) German utility model G 92 03 270.2.
• a tool 8 is attached to a working piston 24 of a working cylinder 3 by means of a force transmission device 25.
• This tool 8 forms part of the entire, portable and very mobile hydraulic tool which can be held by the operator in two handles 5 and 6 and actuated via a switch 7.
• the hydraulic circuit for operating the working cylinder 3 is controlled by means of the switch 7 via a control valve arrangement (not shown).
• the pressure of a hydraulic fluid used in the hydraulic circuit is generated by the hydraulic high-pressure pump 2, which is driven by an electric motor 1, which receives its power supply via an electrical connection 9.
• the hy Draulic high-pressure pump 2 comprises a swash plate 18 which is supported by an angular contact ball bearing 26 and which compresses by means of pistons 10, the hydraulic fluid entering through an inflow opening 13 and supplies them to a collecting duct 15 via check valves 12.
• the hydraulic fluid is supplied to the working piston 24 via a feed bore (not shown) or discharged via a return bore 29.
• a ring accumulator 19, which extends around the working cylinder 3, serves to absorb the hydraulic fluid, in compensation for the movements of the working piston 24, an annular piston 20 being under spring load and carrying out a corresponding compensating movement.
• the ring buffer 19 is arranged around the working cylinder 3 in the case of the G 92 03 270.2; seen axially from the hydraulic high-pressure pump 2, it is connected to the hydraulic circuit via corresponding connecting lines or bores.
• the number of sealing points is relatively high in this arrangement.
• the ring accumulator is arranged around the hydraulic high-pressure pump, in the form of a cylinder jacket. This eliminates the need for longer connecting lines and the associated sealing points.
• the hydraulic drive unit according to the invention is of very compact construction and has only a connection to the outside for the (electrical) drive (on the right in FIG. 2) or the hydraulic output (on the left in FIG. 2). Otherwise, the hydraulic drive unit forms a closed structural unit, the manufacture of which is also simplified as a result.
• venting is easier to carry out on the one hand and hydraulic control is more precise on the other hand.
• FIG. 1 in the left part of the figure, a partially broken-open sectional view of a part of the hydraulic tool, which essentially comprises the drive unit; in the right part of FIG. 1 a partial sectional view along the line A-A;
• Figure 3 is a sectional view taken along line B-B in Figure 2;
• FIG. 4 shows a sectional illustration of a hydraulic tool according to G 92 03 270.2.
• the invention will now be explained using an exemplary embodiment, the functionally corresponding components, which are also shown in FIG. 4, being provided with reference numerals which are increased by 100 compared to FIG. 4.
• the hydraulic tool 1 shows one of the two handles 105 and the switch 107 for operating the hydraulic tool.
• the electrical connection 109 is provided, which supplies the electric motor 101 with energy.
• the energy supply can be ensured via the public power grid, a portable power generator or a battery.
• the hydraulic high-pressure pump which is driven by the electric motor 101 directly or via a transmission (not shown), is designated by 102.
• the hydraulic high-pressure pump 102 is described in more detail below with reference to FIG. 2.
• a ring accumulator 119 is arranged around the hydraulic high-pressure pump 102, which essentially has the shape of a cylinder jacket. Inside the ring accumulator 119 there is an annular piston 120, which is essentially L-shaped, the longer leg extending in the axial direction and having a recess pointing radially inwards, which forms an annular space 134 which is in the right dead center position (FIG 1) of the annular piston 120 is connected to the interior of the hydraulic high-pressure pump 102 via two radially extending connection bores 132 and 133.
• the annular piston 120 is provided with a seal 135 opposite the exterior of the hydraulic high-pressure pump 102; the shorter leg of the annular piston 120 extends in the radial direction and is equipped with a seal 136 which seals the ring buffer 119 to the outer jacket.
• a spring 137 is arranged in the ring accumulator 119, which loads the annular piston 120 and presses to the right in FIG. 1.
• the hydraulic drive unit forms a compact unit in which the drive via the electric motor 101 is required at one end (on the right in FIG. 1) and the output via two at the other end (on the left in FIG. 1) Feed lines 139 (Fig. 2) takes place.
• the hydraulic drive unit is actuated via the switch 107, which in turn actuates the control slide 140 by means of the control rocker 131.
• a microswitch 122 is provided for switching the electric motor 101 on and off. Since the ring accumulator 119 "is integrated in M the hydraulic high-pressure pump 102 and is not arranged around the working cylinder as before, a much more compact design is possible.
• the hydraulic high-pressure pump 102 is shown in FIG. 2.
• the hydraulic high-pressure pump 102 is driven by means of the swash plate 118 with a constant angle of attack, which moves the pistons 110 back and forth in the cylinders.
• the swash plate 118 is in turn driven by the electric motor 101, a roller bearing, preferably an angular contact ball bearing 126, being arranged between the swash plate 118 and the electric motor 101 for storage purposes.
• the pistons 110 together with the cylinders form compression chambers 111 at the end facing away from the swash plate 118, the ejection openings of which can be closed by check valves 112.
• the cylinders are preferably made of hard metal; this has the advantage that the expansion of the cylinder bores is relatively small at very high pressures.
• the pressure generated by the hydraulic high-pressure pump 102 is fed to a collecting duct 115, which is located between the hydraulic high-pressure pump 102 and the working cylinder (not shown).
• the electric motor 101 can be controlled via the switch 122 (FIG. 1), and on the other hand the hydraulic fluid is supplied or discharged to the working cylinder via the two supply lines 139 by means of the control slide 140.
• Fig. 3 shows part of the hydraulic drive unit in section, the control slide 140 is set so that the hydraulic fluid can flow through the center of the two supply lines 139; furthermore, a filling valve 116 is shown, which is used in the filling of the hydraulic circuit with hydraulic oil.
• the reference number 117 denotes an adjustable pressure relief valve; this protects the drive unit from overload and allows the pressure in the hydraulic circuit to be adapted for different purposes.
• a pressure gauge can be connected to port 114.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Supply Devices, Intensifiers, Converters, And Telemotors (AREA)
• Reciprocating Pumps (AREA)
• Vehicle Body Suspensions (AREA)
• Fluid-Pressure Circuits (AREA)
• Braking Systems And Boosters (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=6492777

Family Applications (1)

Country Status (4)

Families Citing this family (5)

Family Cites Families (7)

• 1993
  • 1993-07-14 DE DE4323574A patent/DE4323574C1/de not_active Expired - Fee Related
• 1994
  • 1994-07-29 EP EP94924302A patent/EP0783395B1/fr not_active Expired - Lifetime
  • 1994-07-29 DE DE59407023T patent/DE59407023D1/de not_active Expired - Fee Related
  • 1994-07-29 WO PCT/EP1994/002530 patent/WO1996004107A1/fr active IP Right Grant
  • 1994-07-29 AT AT94924302T patent/ATE171661T1/de not_active IP Right Cessation

Non-Patent Citations (1)

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