JP4381816B2 - Equipment for pressure regulation of hydraulic pumps - Google Patents

Abstract

Device for pressure regulation of a hydraulic pump for pumping a hydraulic medium under pressure, comprising delivery-quantity regulation; a piston unit including first biasing element; a piston member; a first surface on the piston member to be biased by a first biasing force of the hydraulic medium in a first direction; a second surface on the piston member engaged by the first biasing element to be biased by a second biasing force in a second direction, opposite to the first direction; second biasing element to bias the piston member in addition to the hydraulic medium and the first biasing element, thus influencing the pressure of the hydraulic medium.

Description

The present invention relates to a discharge amount adjusting device for supplying lubricating oil for a combustion engine,
An adjusting piston and an adjusting spring for controlling the discharge amount adjusting device, and
Having a control device for this adjusting piston,
The present invention relates to a device for adjusting the pressure of a hydraulic pump, particularly an oil pump.
This type of regulator has the task of adapting the discharge output of the hydraulic pump, and in particular the oil pump, to the alternating demand of the combustion engine lubrication system, for example with regard to oil pressure and oil quantity. This avoids an unnecessarily high oil pressure and keeps the drive output of the lubricating oil pump low in view of the good efficiency of the combustion engine.

  Known oil pumps having a discharge amount adjustment device-in the case of these oil pumps, the oil discharge amount corresponds to the demand of the combustion engine to be supplied in accordance with the oil pump configuration-an oil pump with a bypass adjustment device It has less oil pump drive output than. These discharge amounts are basically adjusted by the oil pressure, in which case appropriate discharge amount adjustments are made, especially at relatively high engine speeds and slight operating temperatures.

  In the case of a simple oil pump specification having a discharge amount adjusting device, the oil pressure is set directly by an adjusting spring. In this embodiment, however, the spring configuration must be made in accordance with the maximum oil pressure demand at the maximum engine speed of the combustion engine, which in this case has a correspondingly high drive output. It has the disadvantage that the necessary high oil pressure results in the lower rotational speed range. For example, as disclosed in German Patent No. 3028573 (Patent Document 1) and German Patent No. 3528651 (Patent Document 2), the discharge amount is adjusted only by one adjusting spring. Furthermore, with the increasing stroke of this adjusting spring, the increasing spring force of this adjusting spring induces an additional oil pressure increase, so that the advantage of the drive output that is to be achieved by reducing the discharge rate is achieved. As a result of unnecessary oil pressure increase, it is at least partially compensated again.

The outer gear oil pump having an axial gear sliding device proposed in German Patent Publication No. 10043842 (Patent Document 3) further has an undesired oil pressure increase in adjusting the discharge amount. The oil pressure level is avoided by a throttling adjustment device that performs a stabilizing action. The oil pressure of this outer gear oil pump is pulsated by a change in the axial meshing overlap of both discharge gears in the case of adjusting operation, however, only a little, always due to adjustment (permanent) . To do. Frictional forces acting against the axial gear sliding amplify this effect. In order to further minimize the discharge and the oil pressure, which corresponds to a relatively low oil pressure demand, especially at low engine speeds, the throttle adjustment device additionally comprises an electrical control component. Need.

  In German Patent Publication No. 19915737, a method for adjusting the lubrication of a combustion engine is described, in which case adjustment of the oil pump depends on the operating state of the combustion engine. Depending on the characteristic map, the characteristic quantity being extracted from the engine control device. An adjustment member not described in detail for this oil pump converts this electrical control into a change in the discharge output of this oil pump.

German Patent No. 735580 (Patent Document 5) describes an oil pump having a discharge amount variable in rotation speed. In the case of this oil pump, the centrifugal force controller of the injection pump is a mechanical pump. The discharge amount of the oil pump is changed through the connecting portion. Other embodiments of adjustable oil pumps are found in German Offenlegungsschrift 3,726,800 and U.S. Pat. No. 4,828,462.
German Patent No. 3028573 German Patent No. 3528651 German Patent Publication No. 10043842 German Patent Publication No. 1915737 German Patent No. 735580 German Patent Publication No. 3726800 US Pat. No. 4,828,462

  Starting from this known technique, the problem underlying the present invention is that the oil pressure and the oil discharge amount are more reliable in a more reliable state, for example depending on the pre-determined operating value of the operating speed of the combustion engine. To provide a regulating device for an oil pump with a discharge rate regulating device that sufficiently minimizes the hydraulic supply demands and accordingly reduces the drive output of the oil pump It is.

In order to solve this problem, a device for pressure regulation of a hydraulic pump having the features described in the opening paragraph has been proposed, which has a working surface for the oil pressure at which the regulating piston always operates. And can be loaded with additional force by the control device. This causes the oil pressure to be adjusted at least in two adjusting pressure stages. For this purpose, the adjusting piston, which can be loaded with a variable force by the control device, performs a corresponding adjustment of the discharge amount adjusting device.

  The invention will now be described in detail with reference to the figures in terms of functions and possible implementations.

  FIG. 1 shows a first embodiment of a pressure control device according to the invention for an outer gear oil pump having a discharge rate adjusting device. In this case, the oil pump includes an oil pump housing 1, and a drive gear 3 fixed to the drive shaft 2 is disposed in the oil pump housing 1. The drive shaft 2 is supported in a lid piston 5 belonging to the closing lid 4. When adjusting the discharge amount, the sliding gear 6 in meshing engagement with the drive gear 3 is slid in the axial direction relative to the drive gear 3 in a known manner. The oil discharge amount is appropriately changed according to the changed gear meshing width.

The sliding gear 6 is supported by a non-rotating pin 7 that supports the sliding piston 8 on the right side and the spring piston 9 on the left side. The formed combined body is displayed as the sliding unit 10. The sliding unit 10 is always loaded with oil pressure in the sliding piston 8 of the sliding unit, and in addition to this, in the state of acting in the opposite direction, The piston spring 11 and the control pressure that can be adjusted in the operating state in the spring chamber 12 adjust the discharge amount.

The adjustment of the control pressure acting in the spring chamber 12 is effected by the adjustment piston 14 via the control bore 13, which is always at the oil pressure via the coupling 16 at the working surface 15 of this adjustment piston. So it is loaded. As a counter force against this load, the adjustment spring 17 acts on this adjustment piston 14 on the left side. In the adjustment position of the adjustment piston 14 shown, the adjustment piston adjustment plug 18 is located directly relative to the control bore 13. The adjustment plug 18 is bounded by a pressure groove 19 on the left side and by a pressure release groove 20 on the right side.

  Since the adjustment plug 18 is only slightly narrower than the diameter of the control bore 13, it acts in the pressure groove 19 via a further coupling 21 in the illustrated adjustment position in the spring chamber 12. The control pressure that exists between the oil pressure and the complete pressure unloading that can be supplied via the pressure relief groove 20 is adjusted. This pressure relief groove 20 is connected to the surrounding environment via diagonal perforations 22 in the adjustment piston 14.

  As soon as the oil pressure acting on the working surface 15 exceeds the maximum required hydraulic oil pressure of the combustion engine to which it belongs, for example 5 bar, the adjustment piston 14 slides against the force of the adjustment spring 17. The control pressure in the spring chamber 12 is reduced. Thus, the sliding unit 10 is slid to the left until the oil pressure reaches a target value of 5 bar, for example, for the purpose of reducing the discharge rate. Below the target oil pressure of 5 bar, on the contrary, induces the sliding of the adjusting piston 14 to the right by the adjusting spring 17, which corresponds to the discharge rate due to the increase of the control pressure in the spring chamber 12. The increase is caused by the resulting increase in oil pressure.

  The control device for the adjusting piston 14 required for the oil pressure drop according to the invention consists of a magnet coil 23 which, in appropriate control, is controlled by a combustion engine control device. A magnetic additional force is exerted on the adjusting piston 14 via the armature 24. This change in the magnetic applied force is carried out continuously or step by step by the control device, which has a corresponding effect on the adjustment of the oil pressure and the oil pump discharge rate. .

The first hydraulic couplings 16, 21 and 26 that diverge behind the oil filter 25 into the sliding piston 8 and the adjusting piston 14 have two advantages.
On the one hand, by adjusting the pressure of the oil pump, the oil pressure is adjusted to the target pressure level behind the oil filter 25, and thus does not depend on the pressure loss of the oil filter 25 that fluctuates due to contamination. Reliable oil pressure for combustion engine lubrication is guaranteed. On the other hand, all the members of the adjusting device and all the bearing parts of the oil pump, for example, the bearing portion of the drive shaft 2 in the lid piston 5 from the sliding chamber 28 through the oil perforations 27 are filtered oil. Thus, the operational reliability of the oil pump as well as the service life is increased.

  FIG. 2 shows yet another embodiment of the present invention having a continuously variable oil pressure regulator. Due to the oil pressure drop according to the invention, here an adjustable spring abutment for the adjusting spring 17 of the adjusting piston 14 shown here without being sectioned, instead of the magnet coil 23 of FIG. A step motor 29 having 30 is used. Depending on the basic position of the spring abutment 30 of the adjusting spring 17 which is automatically adjusted without electrical control of the stepping motor 29, i.e. the corresponding preload of the adjusting spring 17, a maximum required, for example 5 bar. The operating oil pressure is guaranteed. With properly programmed combustion engine controls, this oil pressure is further increased in a drop or special application as well.

FIG. 3 shows an advantageous embodiment of the oil pressure and discharge amount adjustment device according to the invention in the example of an outer gear oil pump, in which case the control device of the adjustment piston comprises: It takes place exclusively in the regulated pressure stage state associated with the two rotational speeds, depending on the centrifugal force. Here, the adjustment piston formed as the step piston 51 is derived from the adjustment piston 14 of FIG. The adjustment piston has an adjustment spring 52 on the left side and a first action surface 53 on the right side, and this first action surface is always loaded with oil pressure. The second working surface 54 on the right side of the stage piston 51 is likewise loaded with oil pressure at low combustion engine operating speeds, so both working surfaces 53, 54 and appropriately configured. Due to the action of the oil pressure on the adjusted adjustment spring 52, the oil pressure adjustment takes place at the first adjustment pressure stage, for example at 2.5 bar. The oil pressure level required for the engine in the case of a high engine speed for an oil pressure level of the second adjusting pressure stage, for example 5 bar, for the appropriate adjusting function of this stage piston 51 is This requires complete pressure unloading of the second working surface 54. In this embodiment, a control device for switching between both adjusting pressure stages by oil pressure loading or pressure unloading of the second working surface 54 of the stage piston 51 is provided in the drive gear 55. It consists of a centrifugal force valve that acts depending on the rotational speed.

  FIG. 4 belonging to FIG. 3 shows a compact centrifugal valve. The centrifugal force valve includes a switching piston 56 and a switching piston spring 57. The switching piston 56 is tilted and oriented with respect to the radial centrifugal force direction for spatial reasons, however, in certain situations, it is also oriented in the radial direction, i.e. The orientation of the switching piston must have at least a radial component. The stepped receiving bores of the switching piston 56 and the switching piston spring 57 are partially and additionally inserted into one tooth of the drive gear 55 for reasons of space. The illustrated position of the switching piston 56 with this relaxed switching piston spring 57 corresponds to a low operating speed at slight centrifugal forces. The guide pin 59 provided on the switching piston 56 ensures radial guidance of the switching piston spring 57 and prevents bending due to the centrifugal force of the switching piston spring 57.

The oil pressure acting on the switching piston 56 via the oil perforation 27 and the peripheral chamfered portion to which the lid piston 5 belongs is also constantly in the chamber of the switching piston spring 57 via the central perforation 60 of the switching piston. Also works. At low operating speeds, this oil pressure is a result of the position of this switching piston 56 shown in FIG. 4 through the inclined bore 61 of the drive gear 55 and through the coupling bore 62 of the oil pump housing 63. To the second working surface 54 of the stage piston 51, thereby leading to actuate the first regulating pressure stage with an oil pressure of, for example, 2.5 bar.

  After exceeding the switching speed for actuating the second regulating pressure stage, for example 2500 / min, the switching piston 56 is outside the switching piston against the switching piston spring 57 due to centrifugal force. Slide to the end position. Due to this, for the oil pressure rise to the second regulating pressure stage of 5 bar, the stage piston 51 is connected to the right side via the inclined bore 61 and the outer peripheral groove 64 of the switching piston 56 and a further section. Pressure is unloaded at the second working surface 54 of this stage piston in such a way that a connection to the central bore 65 of the drive shaft 58 which is open at the end is formed.

  FIG. 5 shows an embodiment, in compliance with FIG. 3, in which the stage piston 51 has two further, different views on the second working surface 54 of the stage piston. 5 can be loaded with oil pressure via the independent control device shown in FIG. As shown in FIG. 5, both of these control devices can operate even when the other control device does not have to be provided in the same manner as each of the control devices becomes functional in the combined state. .

  The first control device has a spiral groove 73 on the drive shaft 74, and this spiral groove is bounded by outer peripheral grooves 75 and 76 on both sides. The spiral groove portion has a relatively small groove depth, and the rotational speed of the drive shaft 74 over the length of the drive shaft is caused by the oil shearing force generated when the drive shaft 74 rotates. A pressure difference depending on the pressure is formed. The left outer peripheral groove 75 is loaded with oil pressure through the oil perforations 27. The inclination direction of the spiral groove 73 is such that when the drive shaft 74 rotates, a pressure difference acting in the spiral groove 73 induces pressure extinction in the right outer peripheral groove 76. Have been selected. The rotation speed variable pressure in the outer circumferential groove 76 is applied to the second working surface of the stepped piston 51 through the longitudinal perforation of the drive shaft 74 and the coupling perforation 79 provided in the housing 78. 54.

  The oil pressure of, for example, 5 bar acting in the outer circumferential groove 75 at a very high rotational speed is reduced to almost 0 bar in the outer circumferential groove 76 due to the relatively high pressure difference formed by the helical groove 73. Thus, the second working surface 54 of the stage piston 51 is effectively pressure unloaded at 5 bar for the desired pressure regulation of the oil pressure. As the rotational speed decreases, the pressure difference in this helical groove 73 decreases continuously, so that the pressure on the second working surface 54 of this stage piston 51 increases correspondingly and the oil pressure adjustment Is carried out at variable pressure levels depending on the rotational speed.

  The control device for the stage piston 51, which can be incorporated alone or in cooperation with the first control device, consists of a solenoid valve 71, which is the oil pressure of the oil pump. When electrically actuated for lowering, the oil pressure on the second working surface 54 of this stage piston is switched. Thus, both working surfaces 53 and 54 are oil pressure loaded, so that this stage piston 51 is already at the force of the adjustment spring 52 at an oil pressure of the first adjustment pressure stage, for example 2.5 bar. In contrast, the adjusting function of the stage piston is performed, and an appropriate control pressure is prepared for adjusting the discharge amount.

  In the solenoid valve 71 that is not energized, the oil pressure supply is cut off, and the pressure unloading or pressure load on the second working surface 54 is induced via the pressure release connection pipe 72 in the solenoid valve 71. The Here, the oil pressure, which no longer acts on the first working surface 53 of the stage piston 51, moves the start of the regulation in that case to a higher value of the second regulation pressure stage, for example 5 bar. . This second regulating pressure stage is guaranteed as a safeguarding oil pressure for all operating requirements of the combustion engine in the event of an interruption due to a failure of the electrical connection of this solenoid valve 71.

  In the exemplary combined functional state of both controllers shown in FIG. 5, in the case of a warm-up combustion engine, the oil pressure adjustment with continuously variable rotation speed is performed through the spiral groove 73. In this case, the solenoid valve 71, however, must then be held closed by means of an additional function, with the solenoid valve being connected to the stage piston 51. In the case of cold operation and in the case of the action of the spiral groove 73 that is not effectively available because it is a viscous liquid oil in that case, in this case, the solenoid valve 71 is in a functional state. Become. In this case, the two-stage oil pressure adjustment of the electromagnetic valve by the pressure load or pressure unloading of the second working surface 54 of the step piston 51 is performed by a known method.

  In principle, the adjustment of the oil pressure carried out with the stage piston 51 can likewise be carried out with a multistage type or with a suitably formed stage piston. In this case, in addition, the partial working surface of this stage piston should be loaded with oil pressure, for example, by a control device formed in a multi-stage manner with the rotational speed being shifted.

  When electrical components are used for adjusting the oil pressure of the combustion engine, it is advantageous to arrange the electronic components outside the crankcase that houses the oil pump. On the one hand, this reduces the load of temperature-sensitive and / or oil-sensitive electronic components, whereas on the other hand, there is no need for electrical coupling to the crankcase. From the outside, the handleability of the electronic component from the outside, for example for repair purposes, is improved. The electromagnetic valve 71 shown in FIG. 5 is attached to the crank casing on the outside, for example. In this case, the electrically switchable oil pressure load on the second working surface 54 of the stepped piston 51 is effected through an oil hole penetrating through the flange surface of the oil pump fixing part in the crank casing. In the electrically formed action of the additional force on the adjusting piston 14 corresponding to FIG. 1 or 2, however, the arrangement of the magnet coil 23 or step motor 29 outside the crank chamber is likewise the same. Need to move together.

  The embodiment in FIG. 6 shows one arrangement selectively with respect to FIG. 2, in which step motor 29, together with adjusting piston 80, is adjusted in a common housing 81. They are grouped into a unit 82. On the outside, this adjusting unit 82 mounted on the crank casing 84 is now connected by a trouble-free electrical connection 83 and through a control bore 87 that penetrates the flange surface 85 to the spring chamber 12 of the oil pump 86. Guarantees reliable oil pump pressure regulation in operation.

In order to further improve the operation reliability, the adjusting unit 82 is supplied with pressure oil purified in the oil filter 89 from the adjacent crank casing main oil perforation 88. The pressure oil is connected to the oil pump via the corresponding coupling section of the adjusting unit 82, on the end face side, against the working surface 90 of the adjusting piston 80 and via the conduit 91 in connection with the constant adjustment. It operates in 86 sliding chambers 28. The necessary pressure unloading on the spring side of the adjustment piston 80 and the oil derivation from the spring chamber 12 during the adjustment of the discharge rate are carried out via the corresponding coupling section of the adjustment unit 82 in the crank casing 84. This is performed in a pressure relief passage 92 that opens into the room.

  In FIG. 7, an electrically controlled adjustment unit 100 operating in two adjustment stages is shown with an arrangement in the crank casing. This adjusting unit is composed of the stage piston 51 already described with reference to FIG. 5, the housing 101 to which it belongs, and the electromagnetic valve 102. As in the embodiment according to FIG. 6, the oil pump 103 is also pressure-adjusted only through the associated control bore 87, also in this two-stage pressure adjustment. Due to this, as well as the pressure load inside the oil pump in the sliding chamber 28 with the discharge oil pressure (conduit 91 removed from FIG. 6), the advantageous simplification of the oil pump is likewise This is also possible in the case of two-stage pressure adjustment. Without electrical control of the solenoid valve 102, the second working surface 54 of the stage piston 51 is pressure unloaded through the left pressure release passage 92 in FIG. The stage piston 51 loaded by the oil pressure only via the face 53 performs the oil pump pressure adjustment with a relatively high pressure regulation level with the adjustment spring 52 of this stage piston. On the other hand, with the electrical control of this solenoid valve 102, the second working surface 54 of this stage piston 51 is likewise loaded by the oil pressure, so that in that case the oil pump 103 pressure Adjustment takes place at the reduced pressure adjustment level.

The adjustment of the oil pressure according to the invention is completely independent of the viscosity depending on the temperature of the discharged oil. Therefore, by the proposed pressure regulation for automobile combustion engine oil pump,
Not only in warm-up engines, but especially in cold daily operation with low oil temperatures after engine start-up, the effectively reduced fuel consumption is significantly reduced by the oil pump drive output that is significantly reduced. Achieved.

  Within the scope of the invention, numerous variants, for example individual features comprising different embodiments of the above-described embodiments, can be combined between each other and / or with known techniques. Similarly, for example, the control device can have many of the components described above.

FIG. 5 is a view of an outer gear oil pump with adjustable discharge, having an electromagnetically variable force load device of the adjustment piston of the outer gear oil pump. FIG. 5 is a view of a discharge rate-adjustable outer gear oil pump with a variable force load device of the adjusting piston of its outer gear oil pump by a step motor. FIG. 5 is a view of a discharge-adjustable outer gear oil pump with a variable, hydraulic force load device of a stepped adjustment piston with a switching piston operated by centrifugal force. FIG. 5 is a diagram of a discharge-adjustable outer gear oil pump with a variable force load device of a regulating piston of its outer gear oil pump by means of a solenoid valve and / or a rotation-dependent oil pressure load device; . FIG. 4 is a diagram of yet another embodiment as a modification to FIG. 3. 3 is another embodiment for FIG. 2. 1 is an advantageous embodiment of the adjustment unit;

Claims (6)

A discharge amount adjusting device comprising a driving gear (3) and a sliding gear (6), and a piston unit (8, 9) attached to the sliding gear (6) on both sides, which is loaded by oil pressure. Have
A hydraulic pump for supplying lubricating oil for a combustion engine, in particular a device for adjusting the pressure of an outer gear oil pump,
The piston spring (11) and the adjustment pressure that assists the piston spring (11) in a state of acting against the oil pressure against the piston unit are used for controlling the discharge amount adjusting device. In the above device in a working manner,
This adjusting pressure is formed by the adjusting piston (14, 51, 80),
This adjusting piston
Working surface (15, 53, 90) for oil pressure acting at all times ,
Adjusting springs (17, 52) acting against this oil pressure, and
A control device (23, 29, 56 and 57, 71 and 73, 102) provided with an additional force acting on the adjusting piston (14, 51, 80) for adjusting the adjusting pressure;
The apparatus characterized by having. Regarding the formation of the control device, one of the following features:
a) the control device of the adjusting piston (14) is formed with a magnet coil (23) having an armature (24) acting on the adjusting piston (14) ;
b) The control device of the adjustment piston (14, 80) is formed with a step motor (29) for adjusting the position of the spring abutment (30) of the adjustment spring (17):
c) The control device of the adjustment piston (51) is formed with a centrifugal valve comprising a switching piston (56) and a switching piston spring (57),
This adjustment piston (51) is formed as a step piston (51),
This adjusting piston has an adjusting spring (52) on the left side and, on the right side, the first working surface (53), which is always loaded with oil pressure, and the oil pressure at a low operating speed of the combustion engine. A second working surface (54) loaded with
This switching piston (56) shuts off the pressure coupling with the second working surface (54) of the adjustment piston (51) at one position and opens at the other position,
The switching piston (56) and the switching piston spring (57) are arranged inside the discharge gear (55) with a partial entry into one discharge tooth in the stepped accommodation perforation. And
This switching piston (56) has a guide pin (59) for radial guidance of the switching piston spring (57), and
In order to be able to arrange a switching piston (56) having a large structural length, this switching piston (56) has an inclination with respect to the radial centrifugal force direction with the axis of this switching piston. In this case, the switching piston (56) is configured to slide to the end position outside the switching piston against the switching piston spring (57) due to centrifugal force. Being:
d) the control device for the adjustment piston (51) is formed with a helical groove (73) formed on the drive shaft (74) fixed to the drive gear (3);
This helical groove (73) is bounded on both sides by outer circumferential grooves (75 and 76),
The helical groove has a relatively small groove depth, and over the length of the drive shaft by the oil shear force generated when the drive shaft (74) rotates. Forms a pressure difference depending on the rotational speed,
This left outer peripheral groove (75) is loaded with oil pressure through the oil perforations (27), and
At this time, the inclination direction of the spiral groove (73) is such that the pressure difference acting in the spiral groove (73) when the drive shaft (74) rotates causes the difference in pressure on the right outer groove (76). Configured to induce pressure extinction in
e) The control device of the adjustment piston (51)
Without electrical control of the solenoid valve (71, 102) or in the event of an electrical system failure, the second working surface (54) of the adjustment piston (51) is connected via the pressure relief passageway (92). Pressure unloading,
Therefore, the adjusting piston (51) loaded by the oil pressure only through the first working surface (53) allows the oil pump pressure adjustment to be made at a relatively high pressure with the adjusting spring (52) of this adjusting piston. At the adjustment level,
On the other hand, with the electrical control of the solenoid valves (71, 102), in addition, the second working surface (54) of the adjusting piston (51) is also loaded by the oil pressure and thus The pressure adjustment of the oil pump (103) is performed at the lowered pressure adjustment level.
Formed with the solenoid valve (71, 102);
The apparatus for adjusting the pressure of the hydraulic pump according to claim 1. The adjustment piston
A first working surface (53) which is always loaded with the pressure of oil discharged by the drive gear (3, 6) via the first hydraulic coupling ;
Via a control device (56 and 57, 71 and 73, 102) with a second working surface (54) that can be pressure loaded and unloaded with oil pressure,
3. The device for adjusting the pressure of a hydraulic pump according to claim 1 or 2, characterized in that it is formed as a stage piston (51). The oil pressure for pressure-loading the working surface ( 15, 53) of the adjusting piston (14, 51 ) is branched downstream of the oil filter (25 ; 89 ) provided on the discharge side of the oil pump. The device for adjusting the pressure of the hydraulic pump according to any one of claims 1 to 3. Regarding the formation of the control device, one of the following features:
a) the control device of the adjusting piston (14) is formed with a magnet coil (23) having an armature (24) acting on the adjusting piston (14);
b) The control device of the adjustment piston (14, 80) is formed with a step motor (29) for adjusting the position of the spring abutment (30) of the adjustment spring (17):
The apparatus for regulating the pressure of a hydraulic pump according to claim 1, wherein one of the following features is provided:
A magnet coil (23) or a step motor (29 ), which is an electrical component of the control device, is mounted on the outside of the crank casing (84) for adjusting the pressure of the hydraulic pump. apparatus. Regarding the formation of the control device, one of the following features:
a) The control device of the adjustment piston (14, 80) is formed with a step motor (29) for adjusting the position of the spring abutment (30) of the adjustment spring (17):
b) the control device of the adjustment piston (51)
Without electrical control of the solenoid valve (71, 102) or in the event of an electrical system failure, the second working surface (54) of the adjustment piston (51) is connected via the pressure relief passageway (92). Pressure unloading,
Therefore, the adjusting piston (51) loaded by the oil pressure only through the first working surface (53) allows the oil pump pressure adjustment to be made at a relatively high pressure with the adjusting spring (52) of this adjusting piston. At the adjustment level,
On the other hand, with the electrical control of the solenoid valves (71, 102), in addition, the second working surface (54) of the adjusting piston (51) is also loaded by the oil pressure and thus The pressure adjustment of the oil pump (103) is performed at the lowered pressure adjustment level.
Formed with the solenoid valve (71, 102);
The apparatus for regulating the pressure of a hydraulic pump according to claim 1, wherein one of the following features is provided:
The adjustment pistons (80, 51) are grouped together with the step motor (29) or the solenoid valve (102) into the adjustment unit (82, 100) in a common housing (81, 101),
This adjusting unit is in pressure coupling with the oil pump (86, 103) via a hydraulic conduit (87) leading to the flange surface (85) to the spring chamber (12) of the oil pump (86, 103). Being in
A device for pressure regulation of a hydraulic pump characterized by.

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