WO2009124852A1

WO2009124852A1 - Pump for delivering a fluid

Info

Publication number: WO2009124852A1
Application number: PCT/EP2009/053710
Authority: WO
Inventors: Uwe Nigrin
Original assignee: Continental Automotive Gmbh
Priority date: 2008-04-09
Filing date: 2009-03-30
Publication date: 2009-10-15
Also published as: DE102008018018A1

Abstract

A pump for delivering a fluid comprises a cylindrical housing (202) enclosing a cylindrical space (203). An axially moving pump piston (204) is disposed in the cylindrical space. A closing member (207) stops a fluid flow from a fluid feed line (205) to a fluid discharge line (206) in a closed position, and otherwise releases the fluid flow. The pump comprises a controllable actuator (201) with an actuator housing (210) made of electrically insulating material. The actuator housing comprises at least one contact surface (220) in common with the cylindrical housing. The closing member can be coupled to the actuator.

Description

description

Pump for conveying a fluid

The invention relates to a pump for conveying a fluid.

Fuel injection systems of internal combustion engines have a high-pressure accumulator near the engine or a storage line from which or from which the individual fuel injection valves are fed. This high-pressure accumulator is often referred to as common rail. The pumps that supply the high-pressure accumulator should be able to provide the necessary volume flow and the required fluid pressure precisely. Pressure control valves can be used to control a pressure of the fuel storage.

It is an object of the invention to provide a pump which enables precise operation and is inexpensive to manufacture.

This object is achieved by a pump having the features of claim 1.

A pump for delivering a fluid comprises

Cylinder housing surrounding a cylinder space. In the cylinder chamber axially movable, a pump piston is arranged. The pump further comprises a fluid supply line for supplying the fluid and a fluid discharge line for discharging the fluid. A closing body insulates one in a closed position

Fluid flow from the fluid supply to the fluid discharge and otherwise releases the fluid flow. The pump has a controllable actuator, which comprises an actuator housing of electrically insulating material. The actuator housing has at least one common contact surface with the cylinder housing. The closing body can be coupled to the actuator. The closing body and the actuator are arranged so that the closing body is in a non-activated state of the actuator in its closed position. By activating the actuator, a force acting on the closing body changes the position of the closing body, so that the fluid flow is released.

The actuator further comprises an armature space which is surrounded by the actuator housing. In the armature space a magnet armature is arranged axially movable, which is connected to the

Closing body is coupled. A magnetic coil, which is enclosed by the actuator housing, surrounds the armature space and acts in the controlled state, a force on the armature, so that the closing body releases the fluid flow. This represents a cost-effective embodiment of the actuator.

The actuator may comprise at least one further magnetic coil, which in its driven state, a further force on the armature affects, so that the

Closing body is in its closed position. Thus, a shortened closing or opening time of the valve can be achieved.

The armature can with the closing body on a

Coupled coupling element. The actuator housing can be arranged completely inside the cylinder housing. The actuator housing and the cylinder housing can a Have press connection. Thus, a simple and stable coupling of the actuator housing and cylinder housing is possible. The cylinder housing may comprise a metal. The cylinder housing can surround the cylinder chamber in one piece. The actuator may be fixed in the cylinder housing by a fixing element comprising at least one spring which exerts a force on the actuator housing. This allows a quick installation and a stable connection.

The fluid inlet and the fluid outlet can be hydraulically coupled via at least one connecting line. The fluid inlet, the fluid outlet and the connection line may be enclosed by the cylinder housing. The cylinder housing may surround a closing body space in which the closing body is arranged axially movable. The at least one connecting line can connect to the closing body space. The closing body may be partially arranged in the cylinder space. As a result, a relatively simple and therefore inexpensive arrangement is given.

Further features, advantages and further developments emerge from the following examples explained in conjunction with FIGS. 1 to 4.

Show it:

1 shows a schematic representation of a pump according to an embodiment,

FIG. 2 shows a schematic illustration of a section of a pump according to a further embodiment,

FIG. 3 shows a schematic illustration of a section of a pump according to a further embodiment, FIGS. 4A and 4B each show a plan view of a plane along the straight line A-A '.

FIG. 1 shows a pump 100, a pump unit 101, a cylinder housing 102, a cylinder chamber 103, a pump piston 104, a fluid supply line 105, a fluid discharge line 106, a closing body 107 and an actuator 108.

The pump 100 has a pump housing 110. This comprises a crank chamber, in which a drive shaft 111 is arranged. The pump can be driven via the drive shaft 111. The drive shaft drives the pump piston 104. The pump piston 104 is surrounded by the cylinder housing 102 coaxially. The pump piston is mounted axially movable in the cylinder chamber 103 of the cylinder housing 102.

In order to be able to fill the cylinder chamber with fluid, the cylinder housing has the fluid supply line 105. Fluid can be expelled from the cylinder space via the fluid drain 106. By the closing body 107, the fluid flow can be adjusted by the fluid supply line 105 into the cylinder chamber 103. The closing body 107 can stop the flow of fluid in a closed position. Will the

Moving the closing body from the closed position, a fluid flow is possible. On the position of the closing body, the size of the volume flow of the fluid can be controlled.

The closing body 107 is coupled to the actuator 108. The actuator can, in an initial state, which corresponds to a non-driven state, hold the closing body in a position by which the closing body is pressed against the cylinder housing and thus a fluid flow between the fluid inlet, the cylinder chamber and the fluid outlet is prevented. The closing body is lifted off the cylinder housing when the actuator is actuated. The actuator is controlled so that a force acts on the closing body, which moves the closing body from its closed position.

The cylinder housing 102 comprises metal, such as aluminum. The actuator 108 has an electrically insulating material, in particular plastic. The actuator has no further housing comprising metal. The actuator is plugged or pressed into the cylinder housing, for example. It may also have a different mechanical coupling with the cylinder housing, which in particular has no screw or screw connection elements to couple the actuator with the cylinder housing.

By a rotational movement of the drive shaft of the pump piston 104 is moved radially through the eccentric shape of the drive shaft to the center of the drive shaft. In this case, the cylinder chamber 103 is filled with fluid. As a result of the further rotational movement of the drive shaft, the pump piston is moved axially away from the center of the drive shaft and thereby compresses the fluid located in the cylinder chamber. The compressed fluid may be following the

Compression stroke are discharged via the fluid discharge. The pressure can be influenced via the closing body. Over the duration in which the closing body is not in the closed position and the degree of deflection, as far as the closing body lifts from the cylinder housing, the volume flow of the fluid can be determined. If the pump is, for example, a high-pressure fuel pump of an injection system of an internal combustion engine, the fluid subjected to high pressure can become a High-pressure fuel storage, the so-called common rail arrive. The pump is in one embodiment a radial piston pump, in another embodiment, a roller tappet pump. The pump is a pump which is set up to provide a sufficiently high pressure for an injection system of an internal combustion engine.

FIG. 2 shows an actuator 201, a cylinder housing 202, a cylinder chamber 203, a pump piston 204, a fluid supply line 205, a fluid discharge 206, a closing body 207, an actuator housing 210, an armature space 211, a magnet armature 212, a magnet coil 213, a fixing element 214 , a connecting line 215, a spring 216, a closing body space 217, a female connector 218, a spring 219 and a contact surface 220.

The cylinder housing 202 has the fluid supply line 205 and the fluid discharge 206. Between the fluid supply line and the fluid discharge line, the connecting line 215 is arranged to hydraulically couple the fluid supply line and the fluid discharge line. It can also be arranged a plurality of connecting lines to hydraulically couple the fluid supply and the fluid discharge. Via the fluid supply line 205 and the connecting line 215, fluid can be guided into the cylinder chamber 203. The fluid can be guided out of the cylinder chamber via the fluid outlet 206. Hydraulically between the fluid supply line 205 and the fluid discharge 206, in particular hydraulically between the connecting line 215 and the fluid discharge 206, the closing body 207 is arranged. The closing body 207 is arranged to be movable axially in the closing body space 217. The closing body space 217 is surrounded by the cylinder housing 202. In a recess of the cylinder housing 202, which is surrounded by the contact surface 220, the actuator 201 is arranged. The actuator 201 includes the actuator housing 210, the solenoid 213 and the armature 212. The armature 212 is disposed axially movable in the armature space 211. The magnet coil 213 surrounds the armature space 211 and is enclosed by the actuator housing 210. The magnetic coil 213 and the armature 212 are arranged in the initial state to each other so that in the driven state, a magnetic force acts on the armature, which moves it in the direction of the closing body.

For driving the magnetic coil with an electrical voltage, the plug socket 218 is arranged on the actuator housing. The socket 218 and the solenoid 213 are electrically coupled, so that via the socket 218, a voltage can be applied to the solenoid. When a voltage is applied to the solenoid coil 213, a magnetic force acts on the armature 212, which acts on the closing body 207 a force, so that it is moved from the closed position shown and a fluid flow between the fluid supply 205 and cylinder chamber 203 and cylinder discharge 206 is possible. In the illustrated embodiment, the closing body is held by the spring 216 in the closed position, so that the

Closing body is in the non-actuated state of the actuator in its closed position. The magnetic force that can be acted upon by the magnetic coil on the armature is greater than the force of the spring.

The actuator housing 210 is formed of an electrically insulating material. The actuator housing includes, for example, an electrically insulating plastic. The magnetic coil 213 is in the manufacture of the electrically insulating Surrounded material. The shape of the actuator housing is accurately formed with the cylinder housing. The actuator housing has a sealing seat with the cylinder housing. Between the actuator housing and the cylinder housing is no further metallic material layer, for example, a further housing which surrounds the actuator. The non-conductive part of the actuator touches the cylinder housing. The actuator or the actuator housing is surrounded by any other housing, for example made of aluminum, which has a contact surface with the cylinder housing. The

Side surfaces of the actuator housing adjoin the metallic cylinder housing. The material of the actuator housing can be injected directly into the cylinder housing. The shape of the actuator housing is determined by the cylinder housing. The actuator forms with the closing body a valve, for example a volume flow control valve.

The actuator housing 210 has the common contact surface 220 with the cylinder housing 202. In the arrangement shown, no further housing is needed that surrounds the actuator housing 210. In particular, no further housing formed of a metal is needed to mechanically couple the actuator to the cylinder housing. The actuator housing 210, which is formed of an electrically non-conductive material, can be inserted directly into the cylinder housing 202. The actuator or the actuator housing is fixed in the cylinder space via the fixing element and the spring 219. A screw connection between actuator and cylinder housing is not necessary to couple the actuator housing and the cylinder housing. If the actuator housing 210 is injected directly into the cylinder housing, the fixing element 214 and the spring 219 can be dispensed with. The actuator forms with the cylinder housing a single unit. The electrically insulating plastic surrounding the magnetic coil 213 or of which the magnetic coil is completely surrounded, has the direct contact surface 220 to the metallic cylinder housing. Between the cylinder housing and the actuator housing 210 is no further metallic layer, such as a valve housing. The actuator housing may have recesses in which fluid can be guided. The actuator housing may have an outer shape which forms recesses with the cylinder housing, in which fluid can be guided.

The armature 212 and the closing body 207 may be mechanically coupled, for example via a screw connection. The armature and the closing body need not have a mechanical connection. It can also be a separate component, which is designed as a coupling element between the closing body and the armature, be arranged to couple the closing body and the armature.

FIG. 3 shows an actuator 301, a closing body 307, an actuator housing 310, a coupling element 311, a magnet armature 312, a magnet coil 317 and a further magnet coil 314.

The actuator has with its actuator housing 310 made of electrically insulating material on a common contact surface 320 with a cylinder housing. The portions of the actuator housing 310 that are in contact with the cylinder housing may include an electrically non-conductive plastic. In the actuator housing are the

Magnet coils 313 and 314 which surround the armature 312 are arranged. The armature 312 is connected via the coupling element 311 with the closing body 307. The solenoid 313 acts in a driven state, a first force on the armature 312, so that the armature is moved in the direction of the closing body 307. As a result, the closing body 307 is likewise moved out of the closed position shown. When the solenoid 314 is energized, another force directed counter to the first force acts on the armature 312. This force moves the armature again toward the position shown. Because the closing body 307 is mechanically coupled to the magnetic armature 312 via the coupling element 311, the closing body 307 is also moved back into the closed position. By the embodiment with two magnetic coils, the switching time of the valve formed from the actuator and the closing body can be shortened.

In a further embodiment, the actuator is formed without coils. The actuator is formed as a piezo actuator. It comprises piezo elements which can exert a force on the closing body 307 and can move the closing body into its closed position and deflect it out of the closed position.

The cylinder housing may also have further supply and discharge lines to be able to conduct fluid flexibly. For example, the cylinder housing has a further discharge, through which the fluid is guided with the closing body open and a piston upward movement to another point in the fluid circuit, for example in a fluid tank. The socket can be arranged transversely to the axial direction of the cylinder as in the embodiments shown, but the socket can also be arranged in any other orientation. The actuator housing can be pressed into the cylinder housing. In this case, the armature and the closing body form a press connection. There is no further metal material layer between the actuator housing and the cylinder housing. The actuator is waiving another housing directly to the actuator housing, which is electrically insulating, arranged in the cylinder housing of a pump for conveying a fluid. The pump is, for example, a high-pressure fuel pump of an injection system of an internal combustion engine.

The cylinder housing is integrally formed in one embodiment. For example, the actuator is not coupled to the cylinder housing via screw elements or fixed in the cylinder housing by elements of the cylinder housing that are coupled to the cylinder housing via screw elements. The cylinder housing has no threads for coupling with the actuator or the actuator housing and also has no threads for fixing the actuator with coupling elements. The pump is operable in one embodiment without actuator and closing body by the cylinder housing is closed by a sealing body.

By means of the position of the closing body, the fluid flow or the volume flow of the fluid can be controlled and thus the pressure which is provided by the pump can be controlled relatively precisely. In a closed position, the closing body prevents fluid flow from fluid supply to fluid discharge as well as possible. By driving the actuator, a force acts on the

Closing body, so that it changes its position, so that the fluid flow between the fluid supply line and fluid discharge is released. FIGS. 4A and 4B show a plan view of a sectional plane which is formed along the straight line AA 'in FIG.

FIG. 4A shows the closing body space 217 and the

Connecting lines 215, as shown in Figure 2. The connecting lines and the closing body space are spaced from each other. The connecting lines and the closing body space at an angle to each other at an angle to each other, so that the closing body space and the connecting lines in a sectional plane as shown in Figure 2 have a hydraulic coupling. Two connection lines are shown, and only one connection line can be arranged. It can also be arranged more than two connecting lines, for example three or four.

In FIG. 4B, the connecting lines 215 and the closing body space 217 run essentially parallel to one another. The connecting lines connect directly to the closing body space. Fluid, which is to be guided from the fluid supply line via the connecting line in the cylinder chamber, flows directly to the closing body along. There are three connecting lines shown, it can also be arranged fewer connecting lines, for example two. It can also be arranged more than three connecting lines, for example four. Reference sign

100 pump

101 pump unit 102 cylinder housing

103 cylinder space

104 pump piston

105 fluid supply line

106 fluid discharge 107 closing body

108 actuator

110 pump housing

111 drive shaft

201 actuator

202 cylinder housing

203 cylinder space

204 pump piston

205 fluid supply line 206 fluid discharge

207 closing body

210 actuator housing

211 Anchor room

212 Magnetic armature 213 Magnetic coil

214 fixing element

215 connection line

216 spring

217 Locking chamber 218 socket

219 spring

220 contact area

301 actuator 307 closing body

310 actuator housing

311 coupling element

312 magnet armature

313 solenoid

314 solenoid coil II 320 contact surface

Claims

claims

A pump for delivering a fluid, comprising:

- A cylinder housing (202) surrounding a cylinder chamber (203);

- A pump piston (204), which is arranged axially movable in the cylinder chamber (203);

- A fluid supply line (205) for supplying the fluid;

- A fluid discharge line (206) for discharging the fluid; - A closing body (207) which in a closed position, a fluid flow from the fluid supply line (205) to the fluid discharge (206) insulates and otherwise releases the fluid flow;

- A controllable actuator (201) having an actuator housing (210) made of electrically insulating

Material having at least one common contact surface (220) with the cylinder housing, wherein the closing body (207) with the actuator (201) is coupled and the closing body (207) and the actuator (201) are arranged so that the closing body (207) is in a non-actuated state of the actuator (201) in its closed position and that by driving the actuator (201) acting on the closing body (207) force changes the position of the closing body (207), so that the fluid flow released is.

The pump of claim 1, wherein the actuator (201) further comprises:

an armature space (211) surrounded by the actuator housing (210);

- An armature (212) which is arranged axially movable in the armature space (211) and with the closing body

(207) can be coupled; - A magnetic coil (213) which is enclosed by the actuator housing, which surrounds the armature space (211) and the force in the driven state, a force acting on the armature (212), so that the closing body (207) releases the fluid flow.

3. Pump according to claim 2, wherein the actuator (301) comprises at least one further magnetic coil (314) which in its driven state, a further force on the armature (312) effects, so that the

Closing body (307) is in its closed position.

4. Pump according to claim 2 or 3, wherein the armature (312) with the closing body (307) by means of a coupling element (311) is coupled.

5. Pump according to one of claims 1 to 4, wherein the actuator housing (210) is disposed completely within the cylinder housing (202).

6. Pump according to one of claims 1 to 5, wherein the actuator housing (210) and the cylinder housing (202) have a press connection.

7. Pump according to one of claims 1 to 6, wherein the cylinder housing (202) comprises metal.

8. Pump according to one of claims 1 to 7, wherein the cylinder housing (202) surrounds the cylinder chamber (203) in one piece.

9. Pump according to one of claims 1 to 8, which has a fixing element (214) which comprises at least one spring (219), which has a force on the actuator housing (210) and which fixes the actuator (201) in the cylinder housing (202).

10. Pump according to one of claims 1 to 9, comprising at least one connecting line (215) through which the

Fluid inlet (205) hydraulically coupled to the fluid outlet (206) can be coupled.

11. The pump of claim 10, wherein the fluid inlet (205), the fluid outlet (206) and the at least one

Connecting line (215) are enclosed by the cylinder housing.

12. A pump according to claim 10 or 11, wherein the cylinder housing surrounds a closing body space (217), in which the closing body (207) is arranged axially movable and connects the at least one connecting line (215) to the closing body space (217).

13. Pump according to one of claims 1 to 12, wherein the closing body (207) partially in the cylinder chamber (203) is arranged.