EP3063412A1

EP3063412A1 - Adjustable coolant pump

Info

Publication number: EP3063412A1
Application number: EP14809754.6A
Authority: EP
Inventors: Franz Pawellek
Original assignee: Nidec GPM GmbH
Current assignee: Nidec GPM GmbH
Priority date: 2013-10-30
Filing date: 2014-10-22
Publication date: 2016-09-07
Also published as: CN105874208A; WO2015062565A1; US20160215679A1; KR20160078365A; JP2016535833A; DE102013018205B3

Abstract

The invention relates to an adjustable coolant pump for use in the cooling circuit of internal combustion engines. The problem addressed by the invention is that of developing an adjustable coolant pump driven by the engine, which pump requires no external power for pressure or volume-flow adjustment, which guarantees a high reliability and an optimal heating of engines with high engine outputs relative to the engine displacement, which outputs demand coolant pumps of large design. The adjustable coolant pump according to the invention comprises an impeller (5) arranged rotationally fixed on a pump shaft (4) and a spring-loaded ring piston (7) guided axially in a pump housing (1) by a return spring (6), on which ring piston a control slide valve (12) arranged in the pump interior (9) is rigidly fastened, and which is characterized in that the ring piston (7) and a filter sleeve (29) provided with laser holes (28) form together with other components in the interior of the coolant pump a ring-cylinder-shaped spring pressure chamber (31) which is connected to a pressure chamber (18) arranged on the pump shaft side, wherein a pilot valve (20) is arranged on the impeller side end of the pump shaft (4) in such a way that the valve piston (24) closes a shaft bore (25) arranged centrally in the pump shaft (4), which shaft bore discharges into the pressure chamber (18) via cross bores (26) arranged in the pump shaft (4).

Description

Adjustable coolant pump

The invention relates to a controllable coolant pump, in particular for use in internal combustion engines.

As part of the optimization of internal combustion engines, these engines tend to have steadily increasing engine power at constant or often decreasing displacement.

The cooling capacity of the coolant pumps must imperatively be adapted to these increasing engine outputs, so that the associated coolant pump must apply a correspondingly high flow rate already in the lower engine speed range for the engines with increasing engine power, and must therefore be dimensioned large, which inevitably increases the space requirement in the engine Engine compartment required. However, in order to prevent the delivery pressure generated by the coolant pump from rising so much with increasing rotational speed that components such as heat exchangers are destroyed as a result of a resulting pressure build-up in the cooling system of the internal combustion engine, a wide variety of pressure control functions are used. But their use again requires a further space in the engine compartment and also often for the operation of auxiliary power, via supply lines, which also require even more space, must be provided.

Thus, overpressure safeguards, for example via bypass lines, are realized in the prior art, with solutions of this kind necessarily entailing high energy losses.

Another possibility for realizing a pressure regulating function has been described in DE 881 306 B. This is a centrifugal pump with hydraulically operated control slide. The actuating pressure used is the delivery pressure of the pump. A spring causes the slider to be closed in the normal position / initial position.

The displacement piston is acted upon in this solution on both sides with the delivery pressure. If necessary, the spring chamber can be relieved of pressure via an external valve, thereby introducing an adjustment of the control slide in the "open" direction.

Due to the required inner and outer guide of the slide, this design requires a very costly, complex production, and also an external control valve as well as externally guided discharge line, so that this design requires a lot of space / space requirements. Another major disadvantage of the above-described in DE 881 306 B design is that this solution can not ensure the necessary for coolant pumps fail-safe (fail-safe), since the flow rate of the pump is completely abgeschiebert in case of failure of the scheme. In addition, in this design, on the one hand the sliding piston sealing surfaces are not protected from the entrained particles from the fluid, and on the other hand, the shaft seal is loaded with the full discharge pressure, so that in addition to the life and the reliability of the pump is severely limited.

In addition, EP Applicants have proposed in EP 1657446 A2 a coolant pump with pressure regulating function which has been proven in practice in the meantime by means of a valve slide, in which this valve slide is adjusted by a central working piston arranged around the pump shaft one abuts around the pump shaft around, the valve spool in the "fully open" starting position adjusting / restoring return spring is applied.

The impeller is also axially displaceable in this design but rotatably mounted on the shaft. Between the pressure incline in the housing and the open impeller, the delivery pressure acts and shifts the impeller when it reaches a preset value against the spring force of a present at the back of the impeller disc spring. Due to the increasing in this axial displacement of the impeller sealing gap with respect to the pressure ramp, the delivery pressure of the pump decreases. The prerequisite for this is that there is a space (i.e., the spring chamber) on the rear side of the impeller with a lower pressure level than the delivery pressure.

But even in this solution requires the coolant pump due to the externally controllable with external power control unit, the solenoid, inevitably a relatively large amount of space.

The "auskommendende" in this solution without external energy actuator / spring element with a pressure control function is a space-constrained diaphragm spring, but in their power / stroke ratio is very limited, so that with this solution, the opening pressure can be adjusted only very inaccurate.

Another solution of a likewise well-proven design of a coolant pump with pressure control function, here again with a control slide, was presented by the applicant in DE 10 2008 026 218 B4 as well as in WO 2009/143832 A2. In this solution, the control slide is arranged on a spring-loaded, axially displaceable annular piston, wherein the control pressure for actuating the control slide generated by a, especially for this purpose designed as a swash plate, rear wall of the pump impingement Axialkolbenpumpe, and is regulated by means disposed in the pump housing solenoid valve.

As a result of the use of the axial piston pump, this solution again requires an increased space in the engine compartment, as well as in conjunction with the use of the solenoid valve again foreign energy with the associated supply lines.

In the prior art, the Applicant also presented in DE 10 2008 022 354 A1 a further likewise time-proven solution, which also provides an active control of the delivery volume flow by means of a spring-loaded by a return spring valve spool, with a rear wall and arranged on this rear wall, allows the outflow of the impeller variable overlapping outer cylinder.

In the solution according to DE 10 2008 022 354 A1, the displacement of the spring-loaded valve slide against the spring force of the return spring causing required hydraulic pressure by means of an electromagnetically operated, arranged outside the pump housing, special axial piston pump is generated and controlled simultaneously.

Another solution is known from DE 10 2012 207 387 A1, by means of a spring-loaded by a return spring valve spool, again with a rear wall and arranged on this rear wall, the outflow of the impeller variable overlapping outer cylinder, hydraulically by means of a 3/2-way Valve can be adjusted, wherein the required for the adjustment of the slide hydraulic pressure is generated by a arranged on the pump shaft of the impeller "second" impeller of another integrated pump housing in the secondary pump.

The invention is therefore based on the object over a drive wheel, driven, continuously variable coolant pump (with control slide) to develop, which avoids all the aforementioned disadvantages of the prior art, also over constant pumps with pressure relief valve has significant energy advantages, in particular no external energy ( such as hydraulics, vacuum, electrical energy) for pressure or volume flow control required, a high reliability (fail-safe) ensures, and the one optimal warming of engines with, based on the displacement, high engine performance, which require very large sized coolant pumps to ensure, and even after the heating of the engine, the engine temperature in continuous operation continuously, highly dynamically, and very reliable over very long periods very accurately is to influence, and at the same time a minimum, optimally use the available space in the engine compartment size should, the to be developed coolant pump also manufacturing and assembly technology is simple, and inexpensive to produce, and over the entire life always high reliability and a to ensure high reliability.

According to the invention, this object is achieved by a driven by a drive wheel controllable coolant pump for internal combustion engines according to the features of the independent claim of the invention.

Advantageous embodiments, details and features of the invention will become apparent from the dependent claims and the following description of the solution according to the invention in conjunction with four representations of the inventive solution.

It show the:

Figure 1: arranged on a motor housing 37, inventive controllable coolant pump in the side view in section;

Figure 2: the pump shaft 4 with the pilot valve 20 in a spatial

Exploded; Figure 3: the detail Z of Figure 1 with a schematic representation of the "control currents" during the "opening phase" of the control slide 12;

Figure 4: the detail Z of Figure 1 with a schematic representation of

"Control currents" during the "closing phase" of the control slide 12.

1 shows the arranged on a motor housing 37 according to the invention, controllable coolant pump with a pump housing 1, a mounted on the pump housing 1 in a pump bearing 2, by a drive wheel 3, here in the form of a pulley 40 driven pump shaft 4, with one on a free , flow-side end of this pump shaft 4 rotatably mounted impeller 5, and with a pump housing 1 axially guided, spring-loaded by a return spring 6 annular piston 7, on which the rear wall 8 of a arranged in the pump interior 9 control slide 12, with a Ausströmbereich 10 of the impeller 5 variable overlapping outer cylinder 1 1, is fixed rigidly, wherein between the pump shaft 4 and the pump housing 1 in a seal receptacle 13, a shaft seal 14 is arranged, and also in the pump interior 9 formed by the pump housing 1, or arranged on the pump housing 1 pump dome 15 are arranged, where one between de m impeller 5 and the rear wall 8 of the control slide 12 in the pump interior 9 positionally fixed wall plate 16 is arranged.

It is essential to the invention that a slide guide 17 is arranged on the pump housing 1 for the spring piston 6 spring loaded by the return piston 6, which guides the annular piston 7 on the outer jacket and is also freely spaced apart with its inner shell of the pump shaft 4.

It is also characteristic that the slide guide 17 rests with the free, flow-side end of the wall plate 16, so that the adjacent components, ie the slide guide 17, the wall plate 16, a at the inner circumference, spaced from the pump shaft 4 by a throttle gap, on the wall plate 16 radially movably arranged sealing disc 33, the pump shaft 4 and the shaft seal 14, together include a ring-cylindrical pressure chamber 18 / form.

The radially movable in the wall disk 16 arranged sealing disk 33, whose inner diameter has little play (tight running fit) relative to the outer diameter of the pump shaft 4, represents a throttle gap, which allows only small leaks in the pressure chamber 18.

It is ensured in conjunction with the entire pump structure according to the invention, by the inventive arrangement of the shaft seal 14 in the pressure chamber 18, that the shaft seal 14 is protected under all operating conditions against impermissibly high pressures, and so a long life of the shaft seal 14 is ensured with high reliability ,

It is also essential that in the slide guide 17, spaced from the wall plate 16 one / more passage bore / s 19 is arranged / are.

It is furthermore essential to the invention that a pilot valve 20, consisting of a set screw 22, a valve spring 23 and a valve piston 24, is provided on the free end of the pump shaft 4 in a valve seat bore such that the valve piston 24 is in the Closing state of the pilot valve 20 a centrally disposed in the pump shaft 4, opening into the valve seat bore shaft bore 25 closes, which opens via one / more arranged in the pump shaft 4 transverse bore / en 26 into the pressure chamber 18. To clarify the structure, the pilot valve 20, the pump shaft 4 is shown with the pilot valve 20 in Figure 2 in a three-dimensional exploded view.

But it is also characteristic that the voltage applied to the annular piston 7 with a spring end return spring 6 with its other spring end to the spring system 27 a provided with laser bores 28 filter sleeve 29 abuts, and this presses sealingly against the wall plate 16.

The laser bores 28 prevent the entry of dirt load and thus increase the reliability of the control device according to the invention. At the same time serve the laser bores 28 in the inventive arrangement as a feed orifice and ensure that no more liquid flows as can proceed via the pilot valve 20.

But it is also essential to the invention that the annular piston 7, a filter piston slide 30 is rigidly arranged, which slides on displacement of the annular piston 7 on the outer circumference of the filter sleeve 29 along, so the filter sleeve 29 freed of dirt load, i. the arranged in the filter sleeve 29 laser bores 28 / (filter bores) cleans of the debris accumulations in the inflow, and thus ensures high reliability, even under extreme conditions of use. It is also characteristic that the annular piston 7 together with the filter piston slide 30, the filter sleeve 29, the wall plate 16 and the slide guide 17 enclose a ring-cylindrical spring pressure chamber 31.

It is also essential that on the outer circumference of the wall plate 16, i. to the outer cylinder 11 out, a control slide seal 32, and the inner circumference of the wall plate 16, the sealing disc 33 is arranged, whereby in the pump interior 9, between the pump shaft 4, the rear wall of the impeller 5, the wall plate 16 and the outer cylinder 1 1 arranged impeller rear side space 34th , pressure side of a between the rear wall 8, the filter sleeve 29, the wall plate 16 and the outer cylinder 1 1 arranged control slide interior 36 is separated, wherein in the control slide interior 36, characterized in that in the rear wall 8 Domdurchführungen 35 are arranged, always built up in the spiral channel 39 working pressure is applied.

After the solution according to the invention has been explained in its construction with reference to Figures 1 and 2, will now be with reference to Figures 3 and 4 on the Functioning / mode of action of the explained in the structure, coolant pump according to the invention will be discussed in more detail.

FIG. 3 shows the detail Z from FIG. 1 with a schematic representation of the "control currents" during the "opening phase" of the control slide 12. In this movement direction of the control slide 12 (in FIG. 3 with a directional arrow R on the control slide 12) shown), the control slide 12 moves in the direction of the pulley 40, thereby opening with its outer cylinder 1 1 the outflow region 10 of the impeller. 5

With increasing speed of the pump shaft 4, the speed of the impeller 5 increases and thus the working pressure increases, i. the pressure in the spiral channel 39. This working pressure builds up in the entire, not specially sealed interior of the coolant pump according to the invention.

In this case, with respect to the working pressure lower pressure of the (against the control slide chamber 36 sealed) impeller rear side space 34 and (with the control slide interior 36 acting on the throttle, provided with laser bores, filter sleeve 29 connected) spring pressure chamber 31 is acted upon.

Since the spring pressure chamber 31 is connected via the passage bores 19 with the pressure chamber 18, and this via the transverse bores 26 with the shaft bore 25, the valve piston 24 of the pilot valve 20 is the same pressure as immediately behind the filter sleeve 29 in the spring pressure chamber 31, this pressure be referred to in the further explanations as a control pressure. This regulating pressure acts on the annular surface of the annular piston 7 acted upon by this pressure. The resulting pressure force is called the control pressure force below. This control pressure force rectified, also attacks the annular piston 7, the spring force of the return spring 6 at. In sum, the control pressure force and the spring force form an opening force acting on the annular piston 7. This opening force tends to move the rigidly connected to the annular piston 7 control slide 12 in the drive-side end position. The opening force is directed against the control slide 12 to a closing pressure force, which emerges from the acted upon at the annular piston 7 with working pressure surface. In the calculation of the closing pressure force, the surfaces of the annular piston 7 (as well as the control slide 12) remain out of consideration, which are applied to the "opposite" with the working pressure and their effects cancel as operating forces on the control slide 12.

FIG. 4 shows the detail Z from FIG. 1 with a schematic illustration of the control currents during the "closing phase" of the control slide 12. In this movement direction of the control slide 12 (shown in FIG. 4 with a directional arrow R on the control slide 12) moves the control slide 12 in the direction of the impeller 5 and thereby closes with its outer cylinder 1 1 the outflow region 10 of the impeller. 5

After the pressure in the working cycle of the annular piston 7 described in connection with FIG. 3 has risen so far (with the control slide 12 arranged on the latter) that the control slide 12 rests in its drive-side end position, the pump shaft 4 increases with increasing speed (ie with an increasing speed) the speed of the impeller 5) of the working pressure inevitably and could endanger the components in the cooling system of the engine without a "Abregelung the working pressure".

However, as a result of the inventive arrangement, with increasing working pressure and on the "throttle", the filter sleeve 29, preset control pressure continuously increases, and this, as already explained, directly applied to the valve piston 24 of the pilot valve 20, when reaching a maximum allowable Working pressure, the pilot valve 20 are preset so that this then opens, while the cooling medium located in the pressure chamber 18, as shown in Figure 4, is emptied into the suction channel 38. In this case, the laser bores 28 in the "inlet aperture", the filter sleeve 29, in Number and size designed / dimensioned so that no more coolant flows through the filter sleeve 29, as can proceed via the pilot valve 20.

In this case, takes place in the pressure chamber 18, as well as in the connected via the passage bore 19 to the pressure chamber 18 spring pressure chamber 31 pressure relief, it decreases the control pressure force, and at constant spring force thus decreases the opening force under the respective working pressure dependent value of the closing pressure force , so that the closing pressure force greater than the opening force now causes a displacement of the annular piston 7 (with the control slide 12 arranged on the latter) in the direction of the impeller 5. In this case, the control slide 12 closes with its outer cylinder 1 1 the outflow region 10 of the impeller 5, and the working pressure decreases.

Even when the engine is switched off, the working pressure drops to zero, and thus the opening pressure as well as the closing pressure drops to zero.

At this force ratio, only the spring force of the restoring spring 6 engages the annular piston 7 and displaces the annular piston 7 (with the control slide 12 arranged thereon) in the drive-side / pulley-side end position, ie. opened to the "full" position.

In the interplay of the explained effects of the arrangement according to the invention results in an optimal control of the working pressure, which avoids the disadvantages of the prior art, has clear energy advantages, no external energy (such as hydraulics, vacuum, electrical energy) required for pressure or flow control, a high Ensures fail-safe, and optimal heating of engines with respect to the displacement, high engine performance, which require very large sized coolant pump ensures and, even after the heating of the engine, the engine temperature in continuous operation continuously, highly dynamically , and very reliable over very long periods of use can be controlled very accurately, and at the same time has a minimal, optimally exploiting the space available in the engine compartment size, also manufacturing and assembly technology is simple, and inexpensive to produce, and ensures a high level of operational reliability and high reliability over the entire service life.

REFERENCE SYMBOL

1 pump housing

2 pump bearings

3 drive wheel

4 pump shaft

5 impeller

6 return spring

7 ring pistons

8 rear wall

9 pump interior

10 outflow area

1 outer cylinder

12 control slide

13 seal receiver

14 shaft seal

15 pump dome

16 wall disk

17 slider guide

18 pressure chamber

19 passage bore

20 pilot valve

21 outlet hole adjustment

valve spring

plunger

shaft bore

cross hole

suspension system

laser drilling

filter sleeve

Filter piston valve spring pressure chamber

Regulator seal Sealing washer

Impeller rear compartment Dome bushing Pusher interior Motor housing

suction

spiral channel

Pulley directional arrow

Claims

claims

1. Controllable coolant pump with, a pump housing (1), a in / on the pump housing (1) in a pump bearing (2) mounted, by a drive wheel (3) driven pump shaft (4), one on a free, flow-side end of this pump shaft ( 4) rotatably mounted impeller (5), with a in the pump housing (1) axially guided by a return spring (6) spring-loaded annular piston (7) on which the rear wall (8) of the pump interior (9) arranged control slide (12), with a the discharge area (10) of the impeller (5) variably overlapping outer cylinder (1 1) is rigidly fixed, wherein between the pump shaft (4) and the pump housing (1) in a seal receptacle (13) has a shaft seal (14) is arranged , And in the pump interior (9) from the pump housing (1) formed, or on the pump housing (1) arranged pump domes (15) are arranged, in which one between the impeller (5) and the rear wall (8) of the control slide (12) in Pumpeninn Enraum (9) positionally fixed positioned wall plate (16) is arranged, characterized

- That on the pump housing (1) a slide guide (17) for the return spring (6) spring-loaded annular piston (7) is arranged, which guides the annular piston (7) on the outer jacket and with its inner shell of the pump shaft (4) is freely spaced , and

- That the slide guide (17) with the free, flow-side end of the wall plate (16) rests, so that the adjacent components, ie the slide guide (17), the wall plate (16), one on the inner circumference of the pump shaft (16) 4) spaced by a throttle gap, on the wall plate (16) radially movably arranged sealing disc (33), the pump shaft (4) and the shaft seal (14), together a ring-cylindrical pressure chamber (18) include / form, and - That in the slide guide (17), spaced from the wall plate (16) one or more passage bore / s (19) are arranged, and

in that, at the free end of the pump shaft (4) on the impeller side, in a valve seat bore, a pilot valve (20) consisting of one adjusting screw (22), one or more outlet bores (21), a valve spring (23) and a valve piston (24) is arranged such that the valve piston (24) in the closed state of the pilot valve (20), a centrally disposed in the pump shaft (4) shaft bore (25) closes over one or more arranged in the pump shaft transverse bore / s (26) opens into the pressure chamber (18), and

- That with a spring end on the annular piston (7) applied return spring (6) abuts with its other spring end on the spring system (27) provided with a laser bores (28) filter sleeve (29) and this presses sealingly against the wall plate (16), and

- That on the annular piston (7) a filter piston slide (30) is arranged rigidly, which slides on displacement of the annular piston (7) on the outer circumference of the filter sleeve (29) along, and

- That the annular piston (7) together with the filter piston slide (30), the filter sleeve (29), the wall plate (16) and the slide guide (17) enclose a ring-cylindrical spring pressure chamber (31), and

- That on the outer circumference of the wall plate (16), ie to the outer cylinder (1 1) out, a control slide seal (32), and on the inner circumference of the wall plate (16), the sealing disc (33) is arranged, whereby in the pump interior (9), a between the pump shaft (4), the rear wall of the impeller (5), the wall plate (18) and the outer cylinder (1 1) arranged impeller rear side space (34) on the pressure side of a between the rear wall (8), the filter sleeve (29), the wall plate (16) and the outer cylinder (1 1) arranged control slide interior (36) is separated, wherein in the control slide interior (36), characterized in that in the rear wall (8) Domdurchführungen (35) are arranged, always applied in the spiral channel 39 working pressure.

2. Controllable coolant pump according to claim 1, characterized in that the pump housing (1) is flanged to a motor housing (37) in which the suction channel (38) and the spiral channel (39) are integrated.

3. Controllable coolant pump according to claim 1 or claim 2, characterized in that the drive wheel (3) is a pulley (40).