DE102017222951A1 - Electromagnetically actuated inlet valve and high-pressure fuel pump - Google Patents

Abstract

The invention relates to an electromagnetically controllable inlet valve (18) for a high-pressure fuel pump, comprising a magnetizable armature (36), which can be actuated in the direction of its longitudinal axis (37), through which a valve member (22) of the inlet valve (18) can be actuated. 36) is delimited, at least in one direction of movement, by a stop element (52) which has a stop surface (64) against which the magnet armature (36) comes into abutment with a contact surface (66) as counter surface. The abutment surface (64) of the abutment element (52) or the contact surface (66) of the magnet armature (36) is arranged on an annular projection (68) projecting from the abutment element (52) or the magnet armature (36) in the direction of the longitudinal axis (37). With respect to the first prestressing (68) offset in the radial direction, a further annular projection (70) is provided on the stop element (52) or on the magnet armature (36) extending in the direction of the longitudinal axis (37) to the mating surface contact surface (66) or stop surface (64) extends less far than the first projection (68). Between the further projection (70) and the mating surface contact surface (66) or abutment surface (64) with its contact surface (68) on the stop surface (64) adjacent armature (36) extending in the direction of the longitudinal axis (37) throttle gap ( Furthermore, the invention relates to a high-pressure fuel pump with such an inlet valve (18).

Description

The invention relates to an electromagnetically actuated inlet valve for a high-pressure fuel pump with the features of the preamble of claim 1. The inlet valve is used to supply the fuel high-pressure pump with fuel. Furthermore, the invention relates to a high-pressure fuel pump with such an inlet valve.

State of the art

From the DE 10 2015 220 383 A1 is an electromagnetically controllable inlet valve for a high pressure pump of a fuel injection system, in particular a common rail injection system known. The inlet valve has a liftable in the direction of a longitudinal axis armature, through which a valve member of the inlet valve is actuated. The lifting movement of the armature is limited in a direction of movement to the open position of the valve member by a stop element. The stop element is annular and has a stop surface on which the magnet armature comes to rest with a contact surface. If the abutment surface and the contact surface are large and there is a large overlap area between them, the mechanical stress on impact of the armature can be kept low. However, when the armature moves away from the abutment member, so-called hydraulic sticking occurs, thereby hindering the movement of the armature. During the movement of the armature away from the abutment surface of the space between the contact surface of the armature and the stop surface must be filled with liquid, which is difficult due to the large areas in the known valve. As a result, the function of the intake valve is impaired, since the timing of closing and opening of the intake valve can not be determined accurately by the delayed movement of the armature. The opening and closing of the inlet valve and, accordingly, the movement of the armature must be done with high dynamics. The size of the stop surface and the contact surface and their overlap surface must be chosen as a compromise of the conflicting requirements. Due to manufacturing tolerances, in the known inlet valve, the stop surface and the contact surface and thus their overlap surface can vary in size, whereby the function of the inlet valve is impaired. The size of the overlapping surface of the stop surface and the contact surface should also not change during operation to ensure reliable operation of the inlet valve.

Disclosure of the invention

The inlet valve according to the invention with the features of claim 1 has the advantage that the size of the overlapping surface of the abutment surface and contact surface is determined only by the size of the surface which is located on the projection. As a result, the size of the overlapping area can be exactly determined and the function of the inlet valve can be improved. The further projection also causes a damping of the movement of the magnet armature when it strikes its contact surface on the stop surface. The size of the abutment surface and / or contact surface can be reduced thereby without heavy wear occurs, whereby the effect of the hydraulic bonding can be kept low by the reduced abutment surface and / or contact surface.

In the dependent claims advantageous refinements and developments of the inlet valve according to the invention are given. The embodiment according to claim 2 and 3, a good inflow and outflow of liquid between the stopper member and the armature is possible. Due to the design according to claim 5, the damping of the movement of the armature is further improved when it hits the stop element.

drawing

Two embodiments of the invention are illustrated in the drawing and are explained in more detail below. Show it 1 a section of a fuel high-pressure pump in a longitudinal section, 2 in an enlarged view a section II the 1 according to a first embodiment of an inlet valve, 3 the inlet valve according to the first embodiment in a cross section along line III-III in 2 and 4 the clipping II with the inlet valve according to a second embodiment.

Description of the embodiments

In 1 is a detail of a high-pressure fuel pump shown, which promotes fuel in a high-pressure accumulator. The high-pressure fuel pump is supplied by a prefeed pump under Vorförderdruck standing fuel. The high-pressure fuel pump has a housing part 10 in the form of a cylinder head, in which in a cylinder bore 12 a pump piston 14 is guided in the cylinder bore 12 a pump workroom 16 limited. The pump piston 14 is driven in a lifting movement, for example by a drive shaft having a cam on which the pump piston 14 for example, via a Tappet, which may be designed as a roller tappet is supported. During the suction stroke of the pump piston 14 becomes the pump work space 16 via an inlet valve 18 filled with fuel and the delivery stroke of the pump piston 14 will fuel through an exhaust valve 20 displaced into the high pressure accumulator when the inlet valve 18 closed is.

The inlet valve 18 is electromagnetically actuated and is in the housing part 10 integrated in such a way that a piston-shaped valve member 22 of the inlet valve 18 in one in the housing part 10 trained hole 24 Hubbeweglich is guided. The valve member 22 of the inlet valve 18 opens into the pump workroom 16 , When the inlet valve is open 18 can fuel from one in the housing part 10 formed low pressure space 26 via inlet bores 28 into the pump workroom 16 to stream. In the closing direction is the valve member 22 from the spring force of a valve spring 30 acted upon, so that the spring force of the valve spring 30 the valve member 22 in the direction of a valve seat 32 draws. To the inlet valve 18 against the spring force of the valve spring 30 to hold open or open is another feather 34 provided, whose spring force is greater than that of the valve spring 30 is. For the operation of the inlet valve 18 an electromagnetic actuator is provided, which is a magnet armature 36 , a magnetic coil surrounding this ring 38 and a pole core 40 includes. The other spring 34 is on the one hand on the armature 36 and on the other hand at the pole core 40 supported. When the solenoid 38 is de-energized, so presses the spring 34 the magnet armature 36 to the valve member 22 out, so that the magnet armature 36 for contact with the valve member 22 passes and the inlet valve 22 opens or keeps open. Will the solenoid coil 38 energized, forms a magnetic field whose magnetic force the armature 36 in the direction of the pole core 40 moves one between the pole core 40 and the armature 36 trained working air gap 42 close. The valve member 22 is relieved in this way, so that the valve spring 30 the valve member 22 in the valve seat 32 to draw.

The working air gap 42 limiting pole core 40 forms an end stop 44 for the lifting magnet armature 36 out. Another end stop 46 for the magnet armature 36 is by a ring collar 48 in a valve body 50 or one on the ring collar 48 supported stop element 52 educated. The valve body 50 has a hole 54 on, which is a receptacle for the magnet armature 36 forms and in which the magnet armature 36 over its outer jacket in the direction of its longitudinal axis 37 Hubbeweglich is guided. The stop element 52 will be explained in more detail below. The axial distance between the pole core 40 and the stopper element 52 determines the stroke of the armature 36 , To the location of the pole core 40 to fix, is the Polkern 40 by means of a sleeve 56 with the valve body 50 firmly connected. The sleeve 56 is preferred for this purpose both with the pole core 40 as well as with the valve body 50 welded.

The magnet armature 36 has an approximately cylindrical shape and in this is the pole core 40 towards a recess 58 formed, for example in the form of a blind bore. In the recess 58 sticks out the spring 34 into it, located at the bottom of the recess 58 supported. The magnet armature 36 also has at least one in the direction of its longitudinal axis 37 running through hole 60 on, preferably several over the circumference of the armature 36 distributed through holes 60 are provided. Through the through holes 60 becomes a connection through the armature 36 on the one hand to the pole core 40 towards the valve member 22 made limited spaces and thus the lifting movement of the surrounded by fuel magnet armature 36 allows. The through holes 60 form passages through the magnet armature 36 ,

The stop element 52 is, for example, sleeve-shaped and has one on the annular collar 48 to the valve member 22 attached to the collar 62 and one in the continuation of the hole 54 protruding cylindrical section 63 on, for example, in the hole 54 is pressed. By the stop element 52 occurs the armature 36 to the valve member 22 through, wherein the inner diameter of the stop element 52 is slightly smaller than the diameter of the hole 54 in the area of the ring collar 48 , On the ring collar 50 remote and the armature 36 facing side, the stop element 52 at his collar 62 a stop surface 64 for the magnet armature 36 on. The magnet armature 36 points to its the stop element 52 facing side a contact surface 66 on the front of the magnet armature 36 is arranged, and with the magnet armature 36 at the stop surface 64 the stop element 52 comes to the plant.

At one in the 2 and 3 shown first embodiment, the stop element 52 one of the end face in the direction of the longitudinal axis 37 to the magnet armature 36 towards projecting annular first projection 68 on which the magnet armature 36 facing end face the stop surface 64 is arranged. The first advantage 68 and thus the stop surface 64 points in the radial direction with respect to the longitudinal axis 37 a smaller extension than the contact surface 66 of the magnet armature 36 , The with respect to the longitudinal axis 37 radially inner edge of the first projection 68 and thus the edge 64a the stop surface 64 is at the inner diameter of the stop element 52 arranged. The with respect to the longitudinal axis 37 radially outer edge of the first projection 68 and thus the edge 64b the stop surface 64 is in radial Direction with respect to the longitudinal axis 37 at a greater distance from the longitudinal axis 37 arranged as the inner edge 68a and at a smaller distance from the longitudinal axis 37 arranged as the radially outer edge of the stop element 52 ,

At the stop element 52 is on the magnet armature 36 facing side another annular projection 70 provided in the direction of the longitudinal axis 37 from the stop element 52 protrudes and the first projection 68 surrounds. The further advantage 70 is in the direction of the longitudinal axis 37 less prominent than the first projection 68 , If the magnet armature 36 with its contact surface 66 at the stop surface 64 the stop element 52 is therefore the further advantage 70 at a distance in the direction of the longitudinal axis 37 from the contact surface 66 of the magnet armature 36 arranged. Between the further projection 70 and the contact surface 66 of the magnet armature 36 is a throttle gap by this distance 72 present, through the fuel from the gap 74 between the first projection 68 and the other lead 70 flow out and can flow into this space.

Between the first lead 68 and the other lead 70 is on the stop element 52 one in the direction of the longitudinal axis 37 opposite the projections 68 . 70 recessed well 76 available. In the in the 2 and 3 the first embodiment shown extends the recess 76 approximately radially to the longitudinal axis 37 and is at least substantially trained. The transitions between the projections 68 . 70 and the depression 76 are rounded. When the magnet armature 36 the stop element 52 approaches, so will fuel from the gap 74 displaced by the throttle gap 72 passes. This will cause the impact of the armature 36 with its contact surface 66 on the stop surface 64 the stop element 52 attenuated. This also reduces the risk that the armature 36 after its impact on the stop element 52 bounces back again.

In 4 is the inlet valve 18 illustrated in a second embodiment, in which the basic structure is the same as in the first embodiment, however, the stop element 52 is modified. The transition from the first projection 68 for deepening 76 is formed obliquely in the second embodiment, wherein the bottom of the recess 76 and the transition to another lead 70 are rounded. Also in the second embodiment is between the further projection 70 and the contact surface 66 of the magnet armature 36 the throttle gap 72 available.

The projections explained above 68 . 70 Alternatively, instead of on the stop element 52 on the magnet armature 36 at its contact surface 66 be arranged. Furthermore, it can be provided that one of the projections 68 . 70 on the stop element 52 and the other of the projections 70 . 68 on the magnet armature 36 is arranged.

The lead 68 on the magnet armature 36 or the lead 70 on the stop element 52 is preferably at least partially outside the through-holes 60 arranged so that when a plant of the armature 36 with its contact surface 66 at the stop surface 64 the stop element 52 the through holes 60 are not completely covered but at least partially free. The lead 68 or. 70 is preferably at least partially offset radially to the through holes 60 arranged.

The above-described embodiments of a contact surface on the magnet armature and a stop surface can also be limited by limiting the stroke movement of the magnet armature 36 in the opposite direction to the pole core 40 be provided. The training of the magnet armature 36 with the contact surface is then as described above and the stop surface may be on the pole core 40 or at one between the pole core 40 and the armature 36 arranged stop element analogous to the stop element 52 be arranged.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102015220383 A1 [0002]

Claims (8)

Electromagnetically actuated inlet valve (18) for a high-pressure fuel pump, comprising an armature (36) which can be moved in the direction of its longitudinal axis (37), through which a valve member (22) of the inlet valve (18) can be actuated, wherein the lifting movement of the magnet armature (36) is limited at least in one direction of movement by a stop element (52) having a stop surface (64) on which the magnet armature (36) comes into contact with a contact surface (66) as counter surface, characterized in that the abutment surface (64) of Stop element (52) or the contact surface (66) of the magnet armature (36) on a in the longitudinal axis (37) from the stop element (52) or the armature (36) protruding annular first projection (68) is arranged and that with respect to the first Vorspungs (68) offset in the radial direction, a further annular projection (70) on the stop element (52) or on the armature (36) is provided which extends in the direction the longitudinal axis (37) to the mating surface contact surface (66) or stop surface (64) extends less far than the first projection (68). Inlet valve after Claim 1 , characterized in that the further projection (70) is arranged in the radial direction at a greater distance from the longitudinal axis (37) than the first projection (68). Inlet valve after Claim 2 , characterized in that the further projection (70) is arranged with respect to the longitudinal axis (37) radially outer edge of the stop element (52) or magnet armature (36). Inlet valve after Claim 2 or 3 , characterized in that the first projection (68) on the stop element (52) or on the magnet armature (36) in the radial direction with respect to the longitudinal axis (37) at the inner edge of the stop element (52) is arranged. Intake valve after one of Claims 1 to 4 , characterized in that the stop element (52) and / or the magnet armature (36) between the first projection (68) and the further projection (70) opposite the projections (68; 70) in the direction of the longitudinal axis (37) recessed recess (76). Inlet valve after Claim 5 , characterized in that the transition between the projections (68; 70) and the recess (76) and / or the recess (76) is rounded. Inlet valve according to one of the preceding claims, characterized in that between the further projection (70) and the mating surface contact surface (66) or abutment surface (64) at its contact surface (68) on the stop surface (64) adjacent magnet armature (36) a in the direction of the longitudinal axis (37) extending throttle gap (72) is formed. A high-pressure fuel pump for a fuel injection system having an intake valve (18) according to any one of the preceding claims, wherein the intake valve (18) is preferably integrated in a housing part (10) of the high-pressure fuel pump.

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