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1. (WO2018138365) CONTROL VALVE ASSEMBLY AND METHOD OF MANUFACTURING THEREOF
注意: このテキストは、OCR 処理によってテキスト化されたものです。法的な用途には PDF 版をご利用ください。

CLAIMS:

1. Control valve assembly (12) of a fuel injector (10), said valve assembly comprising a first valve arrangement (14) wherein a first valve spool (44) is guided in a first hydraulic bore (32) provided in a body (18) of the assembly, said spool (44) being adapted to move between a closed position (CP) wherein a shoulder face (50) of a head member (48) of said first spool is in sealing contact against a first seating face (40) and, a fully open position (OP) wherein a distant end face (52) of said head member is in flush continuity with an under face (29) of the body of the valve assembly, the shoulder face (50) of the first spool being lifted away from said first seating face (40),

characterised in that

the control valve assembly (12) further comprises a first tubular sleeve (24) having a seating portion (64) which end face defines said first seating face (40), the first sleeve being fixed in the first hydraulic bore (32) and the first spool extending through said sleeve (24).

2. Control valve assembly (12) as claimed in the preceding claim wherein the first sleeve (24) further comprises a spool guiding portion (66) integral to the press-fitted seating portion (64), said guiding portion (66) being arranged inside the hydraulic bore (32).

3. Control valve assembly (12) as claimed in claim 2 wherein said spool guiding portion (66) has an inner guiding face (70) against which, in use, slides the spool (44) and, externally an outer face distant from the bore (32) by an outer annular clearance (C66).

4. Control valve assembly (12) as claimed in any of the preceding claims wherein the seating portion (64) is press-fitted in the bore (32) and, it has an inner face (68) defining an inner clearance (C64) with the spool (44).

5. Control valve assembly (12) as claimed in any one of the preceding claims further comprising a second valve arrangement (16), similar to the first

valve arrangement (14), wherein a second spool (54) is guided in a second hydraulic bore (34) provided in the body (18) of the assembly, said second spool (54) being adapted to move between a closed position (CP) wherein a shoulder face (60) of a head member (58) of said second spool (54) is in sealing contact against a second seating face (42) and, a fully open position (OP) wherein a distant end face (62) of said second head member (58) is in flush continuity with an under face (30) of the body of the valve assembly, the shoulder face (60) of the second spool being lifted from said second seating face (42) and, wherein the control valve assembly (12) further comprises a second tubular sleeve (26) having a second seating portion (64) defining said second seating face (42), said second sleeve (26) being fixed in the second hydraulic bore (34), the second spool (54) extending through said second sleeve.

6. Control valve assembly (12) as claimed in claim 5 wherein the second sleeve (26) has an outer face press fitted in the second bore (34) and, an inner face defining a second clearance with the second spool (54).

7. Control valve assembly (12) as claimed in any of the preceding claims wherein the body (18) of the valve assembly comprises a valve guide member (20) provided with the hydraulic bore (32) and, a valve plate (22) having an upper face (28) and an opposed under face (29), the upper face (28) being arranged in surface abutment against an under face (30) of the valve guide member, said valve plate (22) being further provided with a through opening (36) aligned with the hydraulic bore (32, 34), the sleeve (24) being fixed in the valve guide member (20) so that the seating face (40) lies parallel and in close vicinity to the under face (30) of the valve guide member, either slightly recessed inside the hydraulic bore or slightly protruding in the opening.

8. Control valve assembly (12) as claimed in claim 7 taken in combination with either claims 7 or 8, wherein the second hydraulic bore (34) is defined in the valve guide member (20) and, the valve plate (22) is provided with a second through opening (38) aligned with the second hydraulic bore (34), the second sleeve (26) being press fitted in the valve guide member (20) so that the second seating face (42) lies parallel and in close vicinity to the under face (30) of the valve guide member, either slightly recessed inside the second hydraulic bore (34) or slightly protruding in the second opening.

9. Control valve assembly (12) as claimed in any of the claims 7 or 8 wherein between the closed position (CP) and the fully open position (OP), the first spool (44) has a maximum lift (L44) calculated as per the formula:

L44 = (T22 + D40) - H48 wherein

T22 is the thickness of the valve plate (22),

D40 is the offset distance from the first seating face (40) to the valve guide under face (30) and,

H48 is the height of the head (48) of the first spool.

10. Control valve assembly (12) as claimed in any of the claims 7 to 9 wherein between the closed position (CP) and the fully open position (OP), the second spool (54) has a maximum lift (L54) calculated as per the formula:

L54 = (T22 + D42) - H58 wherein

T22 is the thickness of the valve plate (22),

D42 is the distance from the first seating face (42) to the valve guide under face (30) and,

H58 is the height of the head (58) of the second spool.

11. Fuel injector (10) comprising a control valve assembly (12) as claimed in any of the preceding claims.

12. Method (100) of manufacturing a control valve assembly (12) as claimed in any of the preceding claims, the method particularly enabling to ensure a precised valve lift (L44) measured between the closed position (CP) and the fully open position (OP) of the valve arrangement, the method (100) comprising the steps of:

110) providing a valve body (18) defining a hydraulic bore (32);

112) providing a valve spool (44) having a head member (48) joining a core (46) via a shoulder face (50);

114) providing a sleeve (24) adapted to be inserted in said bore (32), said sleeve (24) defining a valve seating face (40);

120) engaging and inserting with press fit said sleeve (24) in said bore (32) so that the seating face (40) is in close vicinity to the under face (30) of the valve body;

130) arranging the valve spool (44) so that the core (46) extends in the sleeve (24) and the head member (48) is outside the sleeve, the shoulder face (50) being able to cooperate with the valve seating face (40);

140) adjusting the position of the sleeve (24) to the desired maximum lift (L44) of the spool.

13. Method (100) as claimed in claim 12 wherein the control valve assembly (12) is provided with a second valve arrangement (16) as set in any of the claims 7 or 8, the steps of the method being:

110) providing a valve body (18) defining a first (32) and a second (34) hydraulic bore;

112) providing a first valve spool (44) having a head member (48) joining a core (46) via a shoulder face (50) and, a second spool (54) having a head member (58) joining a core (56) via a shoulder face (60);

114) providing a first sleeve (24) adapted to be inserted in said first bore (32) and adapted to slidably receive the core (46) of the first spool, the first sleeve (24) defining a first valve seating face (40) and,

a second sleeve (26) adapted to be inserted in said second bore (34) and, adapted to slidably receive the core (56) of the second spool, the second sleeve (26) defining a second valve seating face (42);

120) engaging and inserting with press-fit said first sleeve (24) in said first bore (32) and, said second sleeve (26) in said second bore (34);

130) slidably engaging

the core (46) of the first spool in the first sleeve (24), the first head member (48) protruding outside the first sleeve and,

the core (56) of the second spool in the second sleeve (26), the second head member (58) protruding outside the second sleeve;

140) adjusting the axial position of the first sleeve (24) in the first bore (32) to the desired first maximum lift (L44) of the first spool (44) and, adjusting the axial position of the second sleeve (26) in the second bore (34) to the desired second maximum lift (L54) of the second spool.

14. Method as claimed in claim 13 wherein the control valve body is provided with a valve guide member (20) and a valve plate (22), the providing step 110 is:

110) providing the valve guide member (20) provided with two hydraulic bore (32, 34) and a valve plate (22) provided with two openings (36, 38) complementary aligned to said bores (32, 34).

15. Method as claimed in claim 14 further comprising the steps:

111) measuring the thickness (T22) of the valve plate, this measure being done after providing (110) said valve plate.

113) measuring the height (H48, H58) of each of the spool heads (48,

58), this measure being done after the providing step (112).

16. Method (100) as claimed in any of the claims 14 or 15 further comprising the step:

124) surfacing together the valve guide under face (30) and the two sleeves (24, 26) so that the bottom ends of said sleeves, each defining the seating faces (40, 42), are exactly flush in surface continuity with the valve guide under face (30).

17. Method (100) as claimed in claim 16 wherein the surfacing operation (124) is a grinding operation.

18. Method (100) as claimed in any of the claims 14 to 17 wherein the adjusting step (140) comprises:

142) selecting the maximum lift (L44, L54) possible for each of the first (44) and second (54) spool;

144) fine positioning each sleeve (24, 26) in order to offset the valve seating face (40, 42) from the guide member under face (30) by a distance:

D40 = L44 + H48 - T22 for the first sleeve and,

D42 = L54 + H58 - T22 for the second sleeve wherein:

D40 and D42 are the axial offset distance from the valve guide member under face (30) to the first (40), respectively the second (42), seating face,

H48 and H58 are the head height of the first and second spool and,

T22 is the thickness of the valve plate.