JP4471933B2 - Cylinder head structure of direct injection diesel engine - Google Patents

Description

  The present invention relates to a cylinder head structure for a direct injection diesel engine, in which an injector that directly injects fuel into a combustion chamber of a diesel engine is vertically arranged in a penetrating manner between a cylinder head and a cam holder mounted and fixed on the cylinder head. is there.

  2. Description of the Related Art Conventionally, in a direct injection diesel engine mounted on an automobile, in the cylinder head structure of Patent Document 1, a camshaft is disposed on an upper portion of the cylinder head, and a cam holder that rotatably supports the camshaft is provided on the upper surface of the cylinder head. A plurality of injectors, which are mounted and fixed and directly inject fuel into the combustion chambers of the plurality of cylinders, are vertically arranged in a penetrating manner on the cylinder head and the cam holder.

  In the cylinder head structure of this direct injection diesel engine, the upper part including the valve chamber of the cylinder head is oil-tightly held with respect to the external space by the cylinder head cover, and the upper end portion of the injector is extended from the opening formed in the cylinder head cover. By projecting upward, the workability in the maintenance of the injector, that is, the serviceability is improved.

  The cylinder head and the cam holder are formed with an injector hole and an insertion hole portion through which the injector is inserted, but in order to ensure a sealing property around the injector, an annular shape is formed between the inner peripheral surface of the insertion hole portion and the injector. A seal material is attached, and the vicinity of the outer periphery of the injector hole on the upper surface of the cylinder head is in contact with the vicinity of the outer periphery of the insertion hole portion on the lower surface of the cam holder. In a state where the O-ring is fitted in the annular groove, the O-ring is mounted between the two peripheral portions.

This seal structure prevents water and dust from entering from the outside through the insertion hole and the injector hole, and prevents oil from leaking from the valve operating chamber through the insertion hole and the injector hole. it can.
JP2005-180277

  In the cylinder head structure of the direct injection diesel engine of Patent Document 1, the vicinity of the outer periphery of the injector hole on the upper surface of the cylinder head is in contact with the vicinity of the outer periphery of the insertion hole portion on the lower surface of the cam holder. By attaching the O-ring in a compressed manner, the O-ring can be brought into close contact with both outer peripheral portions to ensure sealing performance, but the cylinder head injector hole located on the upper side of the combustion chamber has an outer peripheral portion in the combustion chamber. A large push-up force associated with the explosion acts, and the push-up force directly and repeatedly acts on the vicinity of the outer periphery of the insertion hole portion of the cam holder, so that the push-up force may cause a crack in the cam holder.

  Therefore, even if it is conceivable that the vicinity of the outer periphery of the injector hole on the upper surface of the cylinder head and the vicinity of the outer periphery of the insertion hole portion on the lower surface of the cam holder face each other with an annular gap, by providing this gap, Since a sufficient sealing pressure cannot be applied to the O-ring by the two peripheral portions, a new problem arises that it is difficult to ensure sealing performance. Although it is conceivable to increase the size of the O-ring, the mounting performance of the O-ring is also deteriorated, and eventually there are concerns that a sufficient sealing performance between the two peripheral portions cannot be secured.

  An object of the present invention is to prevent a cam holder from cracking due to a large thrust force caused by an explosion in a combustion chamber, and to ensure a sufficient sealing performance around an injector, and a cylinder head of a direct injection diesel engine Is to provide a structure.

  2. The cylinder head structure of a direct injection diesel engine according to claim 1, wherein a camshaft is disposed at an upper portion of the cylinder head, and an injector is vertically arranged in the cylinder head in a penetrating manner. A cylinder head cover having an injector hole which is opened on the upper surface of the head and into which the injector is inserted, and an opening in which an upper end portion of the injector protrudes upward while holding an upper portion of the cylinder head in an oil-tight manner with respect to an external space And a plurality of bearing portions corresponding to a plurality of cylinders that rotatably support the camshaft, a connecting portion that connects these bearing portions, and an insertion hole portion that is formed in the connecting portion and through which the injector is inserted, A cam holder placed and fixed on the upper surface of the cylinder head, and an insertion hole of the cam holder; And an elastic seal member disposed between the injector and the injector, and an annular gap between the vicinity of the outer periphery of the injector hole on the upper surface of the cylinder head and the vicinity of the outer periphery of the insertion hole on the lower surface of the cam holder. The seal member is configured to be opposed to each other, and the seal member is formed between the inner peripheral surface of the insertion hole portion and the injector, and is formed inside the seal body and is pressure-bonded to the injector. A first seal portion, a second seal portion that extends downward from the seal body, projects downward from the insertion hole, and is crimped to the vicinity of the outer periphery of the injector hole on the upper surface of the cylinder head, and the second seal portion And a third seal portion that is expanded in diameter by compression deformation caused by pressure bonding and is pressure-bonded to the inner peripheral surface of the insertion hole portion.

  In the cylinder head structure of the direct injection diesel engine, a cam holder is placed and fixed on the upper surface of the cylinder head, and the injector is inserted (inserted) into an injector hole formed in the cylinder head and an insertion hole formed in the cam holder. Thus, the injector is arranged upright in a penetrating manner in the cylinder head, and the fuel is directly injected into the combustion chamber by this injector. The upper part including the valve chamber of the cylinder head is oil tightly held by the cylinder head cover with respect to the external space, and the upper end portion of the injector protrudes upward from the opening formed in the cylinder head cover. Workability, that is, serviceability is improved. The cylinder head located on the upper side of the combustion chamber is configured such that the vicinity of the outer periphery of the injector hole on the upper surface of the cylinder head and the vicinity of the outer periphery of the insertion hole on the lower surface of the cam holder face each other with an annular gap therebetween. A large thrust force associated with the explosion in the combustion chamber acts on the vicinity of the outer periphery of the injector hole, but the thrust force does not act directly on the outer periphery of the insertion hole portion of the cam holder.

  On the other hand, in order to ensure the sealing performance around the injector, a seal member having an elastic seal body and first to third seal portions is disposed between the insertion hole portion of the cam holder and the injector. The seal main body is mounted between the inner peripheral surface of the insertion hole portion and the injector, the first seal portion is formed inside the seal main body, and is crimped to the injector, and the second seal portion is attached to the seal main body. It extends downward and protrudes downward from the insertion hole, and is crimped to the vicinity of the outer periphery of the injector hole on the upper surface of the cylinder head, and the third seal portion is expanded in diameter by the compressive deformation of the second seal portion due to the crimping. And is crimped to the inner peripheral surface of the insertion hole. In this way, an annular gap is formed between the vicinity of the outer periphery of the injector hole on the upper surface of the cylinder head and the vicinity of the outer periphery of the insertion hole portion on the lower surface of the cam holder. And the cylinder head are securely sealed.

Here, the following configuration can be adopted in the invention of claim 1.
The gap is formed by retreating the vicinity of the outer periphery of the insertion hole on the lower surface of the cam holder from the lower surface side to the upper end side of the cam holder (Claim 2). An annular substrate having an L-shaped cross section that is adhered to the outer peripheral surface and the bottom surface of the seal body and fitted in the insertion hole portion is provided, and the third seal portion is provided below the annular substrate. The second seal portion is provided below the three seal portions. The cam holder has a bearing portion and a connecting portion fastened to the cylinder head by a plurality of bolts.

  According to the cylinder head structure of the direct injection diesel engine of claim 1, the cam holder is placed and fixed on the upper surface of the cylinder head, and the injector is inserted (inserted) into the injector hole of the cylinder head and the insertion hole portion of the cam holder. The injector is vertically arranged in the cylinder head so as to penetrate the cylinder head so that the vicinity of the outer periphery of the injector hole on the upper surface of the cylinder head and the vicinity of the outer periphery of the insertion hole on the lower surface of the cam holder face each other with an annular gap. Therefore, a large thrust force due to the explosion in the combustion chamber acts on the vicinity of the outer periphery of the injector hole of the cylinder head located above the combustion chamber, and the thrust force is the outer periphery of the insertion hole portion of the cam holder. Since it does not act unnecessarily directly in the vicinity, the durability of the cam holder is increased and the cam holder is cracked. Door can be reliably prevented.

  By forming the gap, it is difficult for the O-ring as in Patent Document 1 to ensure the sealing performance between the peripheral portions, but there is an elastic seal between the insertion hole of the cam holder and the injector. A seal member having a main body and first to third seal portions is disposed, the seal main body is mounted between the inner peripheral surface of the insertion hole portion and the injector, and the first seal portion is formed inside the seal main body. The second seal portion extends downward from the seal main body and protrudes downward from the insertion hole portion, and is crimped to the vicinity of the outer periphery of the injector hole on the upper surface of the cylinder head, and the third seal portion is attached to the second seal portion. Since the diameter of the seal portion is increased by compressive deformation due to the above-described pressure bonding and is crimped to the inner peripheral surface of the insertion hole portion, a seal mounting process is applied to the vicinity of the outer periphery of the injector hole on the upper surface of the cylinder head. Without any, can be reliably sealed and between the injector and the cam holder, and between the cam holder and the cylinder head. In other words, with this seal member, the gap can be formed and a sufficient sealing performance around the injector can be secured, and water and dust can be reliably prevented from entering from the outside through the insertion hole portion and the injector hole. The oil can be reliably prevented from leaking from the valve operating chamber through the insertion hole and the injector hole.

According to the cylinder head structure of the direct injection diesel engine of claim 2, the outer peripheral vicinity of the insertion hole portion on the lower surface of the cam holder is retreated from the lower surface side of the cam holder to the upper end side, so that the gap is formed. By slightly changing, the outer peripheral vicinity of the injector hole on the upper surface of the cylinder head can be formed into a flat surface, and the gap can be easily formed without increasing the manufacturing cost.

  According to the cylinder head structure of a direct injection diesel engine according to claim 3, an annular substrate having an L-shaped cross section that is adhered to the outer peripheral surface and the bottom surface of the seal body and is fitted into the insertion hole portion is provided. Since the third seal part is provided on the lower side and the second seal part is provided on the lower side of the third seal part, the integrity of the seal body and the seal member having the first to third seal parts is improved, and the seal member It is possible to stabilize the sealing performance by the first to third sealing portions as well as the holding performance.

  According to the cylinder head structure of the direct injection diesel engine of claim 4, since the bearing portion and the connecting portion of the cam holder are fastened to the cylinder head by the plurality of bolts, the cam holder is stably placed on the upper surface of the cylinder head. Can be fixed.

  The cylinder head structure of the direct injection diesel engine according to the present invention is configured such that the vicinity of the outer periphery of the injector hole on the upper surface of the cylinder head and the vicinity of the outer periphery of the insertion hole on the lower surface of the cam holder face each other with an annular gap therebetween. An elastic seal member is disposed between the insertion hole portion and the injector, and the seal member is mounted between the inner peripheral surface of the insertion hole portion and the injector, and inward of the seal body. A first seal portion that is formed and crimped to the injector, a second seal portion that extends downward from the seal body, projects downward from the insertion hole, and is crimped to the vicinity of the outer periphery of the injector hole on the top surface of the cylinder head, And a third seal portion that is expanded in diameter by compression deformation due to the above-described pressure bonding of the two seal portions and is pressure-bonded to the inner peripheral surface of the insertion hole portion.

  1 is a plan view of the entire cylinder head structure 2 of the direct injection diesel engine 1, FIG. 2 is a plan view of the cylinder head structure 2 with a cylinder head cover 30, an injector 40, a seal member 60, etc. removed, and FIG. FIG. 4 is a plan view of the head structure 2 with the cam holder 20 and the camshafts 8 and 9 removed from the state shown in FIG. 2, FIG. 4 is a sectional view taken along line IV-IV in FIG. 1, and FIG. FIG. 2 is a cross-sectional view, and the direct injection diesel engine 1 is an in-line four-cylinder engine in which four cylinders 3 are arranged in the longitudinal direction and fuel is directly injected into the combustion chambers of the cylinders 3. Hereinafter, the direction of arrow a in FIGS. 1 to 3 and 5 will be described as the front.

  As shown in FIGS. 1 to 5, the cylinder head structure 2 of the direct-injection diesel engine 1 includes a pair of left and right camshafts 8 and 9 disposed in the upper part of the cylinder head 10. Four injectors 40 that directly inject fuel into the combustion chambers of the four cylinders 3 are vertically arranged in a penetrating manner.

  The cylinder head structure 2 has four vertical injector holes 14 which are opened on the upper surface of the cylinder head 10 and into which the four injectors 40 are respectively inserted, and the upper portion of the cylinder head 10 is oil-tightly held with respect to the external space. The cylinder head cover 30 having an opening 33 projecting upward from the upper end portions of the four injectors 40, and four vertical insertions through which the four injectors 40 are inserted while rotatably supporting the pair of camshafts 8 and 9, respectively. The cam holder 20 which is formed with the hole 24 and is placed and fixed on the upper surface of the cylinder head 10, and the four elastic holes disposed between the four insertion holes 24 and the four injectors 40 of the cam holder 20. A seal member 60 and the like are provided.

  As shown in FIGS. 3 to 5, a water jacket 11 is formed in the cylinder head 10, a middle deck 12 that partitions the water jacket 11 and the valve operating chamber 4 is formed, and protrudes upward from the middle deck 12. Four boss portions 13 are integrally formed. The four boss portions 13 are arranged side by side in the front-rear direction at the center in the left-right direction of the cylinder head 10 so as to be positioned above the combustion chambers of the four cylinders 3. The four injector holes 14 are formed in the middle deck 12 and the boss portion 13 so as to penetrate vertically, centering on the center line of the corresponding cylinder 3 so as to open on the smooth upper surfaces of the four boss portions 13, respectively. ing. The injector hole 14 includes a large-diameter hole portion 14a that occupies a large portion including the upper portion thereof, and a small-diameter hole portion 14b that is formed from the lower end portion of the large-diameter hole portion 14a via the stepped portion 14c and extends downward.

  The middle deck 12 of the cylinder head 10 has four bolt screw holes 15 into which four bolts 59 for fixing the four injectors 40 are screwed, and a plurality of bolt screws to which a plurality of bolts 29 for fixing the cam holder 20 are screwed. Holes 16 are formed, each bolt screw hole 15 is provided on the rear side of each injector hole 14, and two bolt screw holes 16 are provided on both the left and right sides in the vicinity of the rear side of each bolt screw hole 15. An outer peripheral wall portion 17 extending upward from the middle deck 12 is integrally formed on the outer peripheral portion of the cylinder head 10 over the entire periphery, and a plurality of outer peripheral wall portions 31 of the cylinder head cover 30 are fixed to the outer peripheral wall portion 17. A plurality of fastening holes 18 into which the fastening members 32 are screwed are formed.

  FIG. 6 is a plan view of the cam holder 20. As shown in FIGS. 2 and 4 to 6, the cam holder 20 includes a pair of left and right bearings 21 corresponding to four cylinders that rotatably support a pair of camshafts 8 and 9, and a plurality of bearings. 21 and a connecting portion 22 that connects 21. The plurality of bearing portions 21 and the connecting portion 22 are integrally formed. The connecting portion 22 extends in the front-rear direction and is formed slightly shorter than the front-rear length of the cylinder head 10. The connecting portion 22 is formed with a concave portion 23 that is long in the front-rear direction from the upper side and opens on the smooth bottom surface of the concave portion 4. Two insertion holes 24 are formed in a vertically penetrating manner with a space in the front-rear direction.

  The five pairs of bearing portions 21 are front and rear with respect to the four insertion hole portions 24 so that the bearing portions 21 at both front and rear ends of the five pairs of bearing portions 21 are positioned on both front and rear sides of the four insertion hole portions 24. It is formed so as to protrude from the connecting portion 22 at the position shifted in the direction to the left and right sides. The connecting portion 22 is formed with a bolt insertion hole 26 through which the bolt 59 is inserted on the rear side of each insertion hole portion 24, and a holder support portion 27 is formed in a convex shape on the rear side of each bolt insertion hole 26, Each holder support portion 27 is formed with a pin hole 27a into which the positioning pin 55 is fitted so as to protrude upward.

  A bearing cap 25 is brought into contact with the bearings 25 from the upper side and fixed by the bolts 29 to a total of ten bearing portions 21 in five pairs, and the camshaft 8 is fixed by a plurality of bearing portions 21 and bearing caps 25 on the left side (right side). (9) is rotatably supported. The plurality of bearings 21 and the plurality of bearing caps 25 of the cam holder 20 are fastened together and fixed to the cylinder head 10 by the plurality of bolts 29, and thus the cam holder 20 is placed and fixed on the cylinder head 10 at a fixed position. The centers of the plurality of insertion holes 24 coincide with the center lines of the corresponding cylinders 3, and these insertion holes 24 are in communication with the plurality of injector holes 14 of the cylinder head 10.

  FIG. 9 shows a cross-sectional view of the main part including a part of the cam holder 20, the insertion hole 24 of the cylinder head 10 and the injector hole 14. As shown in FIGS. 4, 5, and 9, the insertion hole portion 24 is formed to have a larger diameter than the injector hole 14 (large diameter hole portion 14 a) of the cylinder head 10. In order from the upper end to the lower side, the upper end hole portion 24a having the maximum diameter, the upper hole portion 24b having a smaller diameter than the upper end hole portion 24a, and the tapered hole portion 24c having a diameter decreasing downward from the lower end of the upper hole portion 24b. A main hole 24d having the same diameter as that of the lower end of the tapered hole 24c is formed, and the main hole 24d has a vertical length that is about 2/3 of the vertical length of the insertion hole 24.

Whereas the upper surface of the boss 13 of the cylinder head 10 is formed flat, the outer peripheral vicinity 20a of the insertion hole 24 on the lower surface of the cam holder 20 is the lower surface of the cam holder 20 (the lower outer surface of the outer peripheral vicinity 20a). ) From the lower surface side of the cam holder 20 to the upper end side, and the vicinity of the outer periphery 10a of the injector hole 14 on the upper surface of the cylinder head 10 (boss portion 13) and the vicinity of the outer periphery. An annular gap 5 having a diameter of about twice that of the injector hole 14 is formed between the portion 20a and the outer peripheral vicinity portions 10a and 20a are opposed to each other with the gap 5 therebetween.

  As shown in FIGS. 1 and 4, the cylinder head cover 30 is formed in a box shape having an opening on the lower side, and is attached to the cylinder head 10 from above, and the lower end surface of the outer peripheral wall portion 31 is the outer peripheral wall portion of the cylinder head 10. 17 is oil-tightly connected to the upper end surface of the member 17 via a sealing material 32 and fastened by the plurality of fastening members 32. A slit-like opening 33 extending in the front-rear direction is formed at the center in the left-right direction of the cylinder head cover 30, and the entire recess 23 of the connecting portion 22 of the cam holder 20 is exposed to the outside from the opening 33.

  The lower end surface of the inner peripheral wall portion 34 that forms the opening 33 of the cylinder head cover 30 is oil-tightly connected to the upper surface of the outer periphery of the groove portion 23 of the connecting portion 22 of the cam holder 20 via a sealing material 35. Thus, with the cylinder head cover 30, the upper part including the valve operating chamber 4 of the cylinder head 10 other than the concave part 23 of the cam holder 20 is exposed in the state where the concave part 23 of the connecting part 22 of the cam holder 20 is exposed to the outside from the opening 33. Along with the part and the pair of camshafts 8 and 9, the outer space is held oil-tight.

  As shown in FIGS. 1, 4, 5, and 7, each injector 40 has a fuel introduction part 40 a at the upper part and a fuel injection port 40 b at the lower end part. In addition, the injector 40 is formed with a holder engaging portion 41 having a narrow neck portion that is recessed so that its cross section is substantially rectangular, slightly above the central portion in the vertical direction, and a lower end portion of the holder engaging portion 41 A large-diameter cylindrical portion 43 that is approximately ½ of the vertical length of the injector 40 is formed below the flange portion 42, and the small-diameter cylindrical portion 44 is formed from the lower end portion of the large-diameter cylindrical portion 43 through the step portion 45. Is formed and protrudes downward, and a fuel injection port 40 b is provided in the small diameter cylindrical portion 44.

  The injector 40 is detachably inserted from above into the insertion hole 24 of the cam holder 20 and the injector hole 14 of the cylinder head 10, and its step 45 abuts on the step 14 c of the injector hole 14 from above and moves vertically. After being positioned, the upper end portion of the injector 40 protrudes upward from the opening 33 of the cylinder head cover 30, and the fuel injection port 14b faces the combustion chamber of the cylinder 3. In this state, the injector is fixed by the fixing mechanism 50 described below. 40 is fixed so as to be unlockable.

  As shown in FIGS. 1, 4, 5, and 8, the fixing mechanism 50 includes an injector holder 51 and the bolt 59. The injector holder 51 has a bifurcated arm portion 52 at the front, a fulcrum 53 at the rear end, and a bolt insertion hole 54 at the center in the front-rear direction. The arm portion 52 is engaged with the holder engaging portion 41 of the injector 40, and the fulcrum portion 53 is placed and supported on the holder support portion 27 of the cam holder 20 in a state of being positioned by the positioning pin 55. A bolt 59 is inserted into the bolt insertion hole 54 from above, and the bolt 59 is inserted into the bolt insertion hole 26 of the cam holder 20 in a loosely fitting manner, and a lower end portion thereof is screwed into the bolt screw hole 15 of the cylinder head 10. Yes.

  By tightening the bolt 59, the downward rotating force acts on the arm portion 52 with the fulcrum portion 53 as a fulcrum in the injector holder 51. Therefore, the injector 40 is pressed downward together with the flange portion 42 by the arm portion 52, and the injector 40 The step portion 45 is fixed in a state where it is crimped to the step portion 14 c of the injector hole 14, and the connecting portion 22 of the cam holder 20 is made into the cylinder head 10 via the injector holder 51 by a plurality of bolts 59. . An annular seal material 56 seals the vicinity of the outer periphery of the bolt insertion hole 26 on the upper surface of the cam holder 20 and the lower surface of the injector holder 51 and the bolt 59.

  Here, the injector holder 51 is mounted in the recess 23 of the cam holder 20, and the injector holder 51 and the bolt 59 face the external space from the opening 33 of the cylinder head cover 30, and the cylinder head cover 30 is mounted. The fixing mechanism 50 can be fixed and released, and the injector 40 and the fixing mechanism 50 can be attached and detached. Therefore, the workability in maintenance of the injector 40, that is, the serviceability is improved.

Next, the seal member 60 will be described.
10 is a cross-sectional view of the seal member 60, FIG. 11 is a cross-sectional view of the main part in a state where the seal member 60 is mounted in the insertion hole 24, and FIG. 12 is a cross-sectional view of the injector 40 through the seal member 60. The sectional view in a state of being inserted through the hole 14 is shown. As described above, the seal member 60 is disposed between the insertion hole portion 24 of the cam holder 20 and the injector 40.

  As shown in FIGS. 4, 5, and 10 to 12, the seal member 60 includes a seal body 61 that is mounted between the inner peripheral surface of the insertion hole 24 of the cam holder 20 and the injector 40, and a seal body 61. A first seal portion 62 that is formed inwardly of the cylinder head 10 and is crimped to the injector 40, and extends downward from the seal main body 61 and protrudes downward from the insertion hole portion 24. A second seal portion 63 that is crimped to the second seal portion, and a third seal portion 64 that is expanded in diameter by compression deformation due to the crimping of the second seal portion 63 and is crimped to the inner peripheral surface of the insertion hole portion 24 of the cam holder 20. The seal main body 61 and the first to third seal portions 62 to 64 are each formed in an annular shape.

  Further, an annular substrate 65 made of metal such as steel or stainless steel having an L-shaped cross section that is adhered to the outer peripheral surface and the bottom surface of the seal body 61 and is fitted into the insertion hole portion 24 of the cam holder 20 is provided. A third seal portion 64 is provided below 65, and a second seal portion 63 is provided below the third seal portion 64. Here, the seal member 60 and the annular substrate 65 will be described in detail.

  The annular substrate 65 includes an annular inner portion including a tubular portion 65a, an annular flange portion 65b protruding radially outward from the upper end of the tubular portion 65a, and a tapered portion 65b projecting radially inward from the lower end of the tubular portion 65a. The cylinder portion 65a, the flange portion 65b, and the inward projection portion 65c are integrally formed by press molding or the like. The cylindrical portion 65a is formed to have substantially the same diameter as the main hole portion 24d of the insertion hole portion 24, and has a vertical length that is about 2/3 of the vertical length of the insertion hole portion 24, and the outer peripheral portion of the flange portion 65b is inserted therethrough. The hole 24 is formed to have a diameter equal to or smaller than the diameter of the upper end hole 24 a, and the inner peripheral portion of the inwardly extending portion 65 c is formed to have a diameter equal to or smaller than the diameter of the large-diameter hole 14 a of the injector hole 14.

  In the seal member 60, the seal body 61 and the first seal portion 62 are integrally formed, and as a separate body, the second seal portion 63 and the third seal portion 64 are integrally formed, and the inside of the cylindrical portion 65 a of the annular substrate 65 is formed. The outer peripheral surface and the bottom surface of the seal body 61 are bonded to the peripheral surface and the upper surface of the inwardly extending portion 65c, and the upper surface of the second seal portion 63 is bonded to the lower surface of the inwardly extending portion 65c. A seal member 60 in which the first to third seal portions 62 to 64 are integrated is configured.

  The seal body 61 is formed in a relatively thick cylindrical shape in which the large-diameter cylindrical portion 43 of the injector 40 can be inserted with a slight gap, and the upper end position of the seal main body 61 is fixed to the annular substrate 65 as described above. The first sealing portion 62 is formed so as to coincide with the upper end of the flange portion 65a of the annular substrate 65 and to align the inner peripheral end position with the inner peripheral end of the inwardly extending portion 65c of the annular substrate 65. The main body 61 is formed so as to protrude inward from the central portion in the vertical direction of the inner peripheral portion.

  The second and third seal portions 63 and 64 generally have a vertical length that is approximately half of the vertical length of the seal body 61, and the upper end portion of the third seal portion 64 is approximately equal to the radial thickness of the seal body 61. Tapered inner circumference which has the same thickness and is entirely bonded to the lower surface of the inwardly extending portion 65c, and the inner peripheral surfaces of the third seal portion 64 and the second seal portion 63 continuously increase in diameter toward the lower side. Formed on the surface. The radial thickness of the lower end portion of the second seal portion 63 is smaller than the radial thickness of the seal body 61, and the outer peripheral surface of the second seal portion 63 is formed on a tapered outer peripheral surface that increases in diameter upward. The upper end of the surface is connected to the substantially straight outer peripheral surface of the third seal portion 64 via a stepped portion projecting radially outward.

  The seal member 60 and the annular substrate 65 are integrally fitted into the insertion hole 24 from above. In this case, the cylindrical portion 65a of the annular substrate 65 is press-fitted into the main hole 24d of the insertion hole 24. The flange portion 65b of the annular substrate 65 is fitted into the upper hole portion 24b of the insertion hole portion 24 so as to be loosely fitted, and the second seal portion 63 of the seal member 60 protrudes downward from the insertion hole portion 24. It becomes a state.

  The injector 40 is inserted through the seal member 60 and the annular substrate 65, is inserted through the insertion hole 24 of the cam holder 20 through the seal member 60 and the annular substrate 65, and is inserted into the injector hole 14 of the cylinder head 10, As described above, when fixed by the fixing mechanism 50, the vertical position of the injector 40 is positioned, and the flange portion 42 comes close to the bottom surface of the upper end hole portion 24 a of the insertion hole portion 24.

  By the insertion of the injector 40, the first seal portion 62 is pressed against the injector 40 while being elastically deformed downward, and the cylindrical portion 65a of the annular substrate 65 is press-fitted into the main hole portion 24d of the insertion hole portion 24. Therefore, the second seal portion 63 protruding downward from the insertion hole portion 24 is pressure-bonded to the vicinity of the outer periphery 10 a of the injector hole 14 on the upper surface of the cylinder head 10, and this second seal portion 63. Due to the compression deformation due to the pressure bonding, the third seal portion 64 is deformed in a diameter-enlarged state and maintained in a state where it is pressure-bonded to the inner peripheral surface of the insertion hole portion 24 of the cam holder 20.

  According to the cylinder head structure 2 described above, the cam holder 20 is placed and fixed on the upper surface of the cylinder head 10, and the injector 40 is inserted (inserted) into the injector hole 14 of the cylinder head 10 and the insertion hole portion 24 of the cam holder 20. The injector 40 is arranged upright in a penetrating manner in the cylinder head 10, and the vicinity of the outer periphery 10 a of the injector hole 14 on the upper surface of the cylinder head 10 and the vicinity of the outer periphery 20 a of the insertion hole 24 on the lower surface of the cam holder 20. Were configured to face each other with an annular gap 5 therebetween.

  Therefore, a large thrust force due to the explosion in the combustion chamber acts on the vicinity 10a of the outer periphery of the injector hole 14 of the cylinder head 10 located above the combustion chamber of the cylinder 3 of the direct injection diesel engine 1. Since the force does not directly and unnecessarily act on the outer peripheral vicinity 20a of the insertion hole 24 of the cam holder 20, it is possible to improve the durability of the cam holder 20 and reliably prevent the cam holder 20 from cracking.

  By forming the gap 5, in the conventional structure, it is difficult to ensure the sealing performance between the outer peripheral vicinity portions 10a and 20a, but the elastic property is provided between the insertion hole portion 24 of the cam holder 20 and the injector 40. A seal member 61 having a seal body 61 and first to third seal portions 62 to 64 is provided, and the seal body 61 is mounted between the inner peripheral surface of the insertion hole portion 24 and the injector 40, A seal portion 62 is formed on the inner side of the seal body 61 and is crimped to the injector 40, and the second seal portion 63 extends downward from the seal body 61 and protrudes downward from the insertion hole portion 24, so that the upper surface of the cylinder head 10 is formed. The third seal portion 64 is subjected to pressure expansion on the inner peripheral surface of the insertion hole portion 24 by compressing the third seal portion 64 by compressive deformation of the second seal portion 63 due to the compression. It was configured to.

  Accordingly, the outer peripheral vicinity portion 10a of the injector hole 14 on the upper surface of the cylinder head 10 is not subjected to processing for attaching a seal, and the gap between the injector 40 and the cam holder 20 and between the cam holder 20 and the cylinder head 10 are securely sealed. In other words, after the gap 5 is formed by the seal member 60, a sufficient sealing performance around the injector 20 can be secured, and water and dust enter from the outside through the insertion hole 24 and the injector hole 14. In addition, oil can be reliably prevented from leaking from the valve operating chamber 4 through the insertion hole 24 and the injector hole 14.

  Further, the outer peripheral vicinity portion 20a of the insertion hole 24 on the lower surface of the cam holder 20 is formed in a stepped shape from the lower surface of the cam holder 20 to form the gap 5, so that the cylinder can be changed by slightly changing the shape of the cam holder 20 The gap 5 can be easily formed without increasing the manufacturing cost by making the vicinity 10a of the outer periphery of the injector hole 14 on the upper surface of the head 10 flat.

  An annular substrate 65 having an L-shaped cross section that is adhered to the outer peripheral surface and the bottom surface of the seal body 61 and is fitted into the insertion hole 24 is provided. A third seal portion 64 is provided below the annular substrate 65, and a third seal portion 64 is provided. Since the second seal portion 63 is provided on the lower side of the seal portion 64, the integrity of the seal body 61 and the seal member 60 having the first to third seal portions 62 to 64 is improved, and the seal member 60 is retained together with the holding performance. The sealing performance by the 1st-3rd seal parts 62-64 can be stabilized.

  Since the plurality of bearing portions 21 and connecting portions 22 of the cam holder 20 are fastened to the cylinder head 10 by a plurality of bolts 29 and 59, the cam holder 20 can be stably placed and fixed on the upper surface of the cylinder head 10. .

In addition, you may change the said Example partially as follows.
1] The shape of the seal member 60, particularly the shapes of the third and fourth seal portions 63 and 64, may be configured in various shapes as long as they have the above functions.
2] The gap 5 may be formed by forming the vicinity 10 a of the outer periphery of the injector hole 14 on the upper surface of the cylinder head 10 in a step-down manner from the upper surface of the cylinder head 10. In this case, by slightly changing the shape of the cylinder head 10, the outer peripheral vicinity 20 a of the insertion hole 24 on the lower surface of the cam holder 20 is made flat, and the gap 5 is easily formed without increasing the manufacturing cost. be able to.

3] In the annular substrate 65, a plurality of inwardly extending portions 65c are provided intermittently in the circumferential direction instead of in an annular shape, and these inwardly extending portions are provided between the seal body 61 and the third seal portion 64 of the seal member 60. You may attach so that it may insert. In this case, the seal body 61 and the first to third seal portions 62 to 64 can be integrally formed.

4] The cylinder head structure 2 of the present invention is not limited to an in-line four-cylinder engine as in the above-described embodiment, and further to a DOHC (double overhead camshaft) engine in which a pair of camshafts 8 and 9 are disposed. The present invention can be applied to various direct injection diesel engines such as an in-line 6-cylinder engine and a SOHC (single overhead camshaft) engine.

It is a top view of the cylinder head structure of the direct-injection diesel engine which concerns on an Example. It is a top view except a cylinder head cover etc. of a cylinder head structure. It is a top view except a cam holder etc. of a cylinder head structure. It is the IV-IV sectional view taken on the line of FIG. It is the VV sectional view taken on the line of FIG. It is a top view of a cam holder. It is a front view of an injector. It is a top view of an injector holder. It is sectional drawing of the principal part of a cam holder and a cylinder head. It is sectional drawing of a sealing member. It is sectional drawing of the principal part of the state which mounted | wore the insertion member with the sealing member. It is sectional drawing of the state by which the injector was penetrated by the penetration hole part and the injector hole through the sealing member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Direct-injection diesel engine 2 Cylinder head structure 5 Gap 8, 9 Cam shaft 10 Cylinder head 10a Outer periphery vicinity part 14 Injector hole 20 Cam holder 20a Outer periphery vicinity part 21 Bearing part 22 Connecting part 24 Insertion hole part 29 Bolt 30 Cylinder head cover 40 Injector 59 Bolt 60 Seal member 61 Seal body 62 First seal portion 63 Second seal portion 64 Third seal portion 65 Annular substrate

Claims (4)

In a cylinder head structure of a direct injection diesel engine in which a camshaft is disposed at the upper part of the cylinder head and an injector is disposed upright in a penetrating manner in the cylinder head,
An injector hole that opens on the upper surface of the cylinder head and into which the injector is inserted; and
A cylinder head cover having an opening in which an upper end portion of the injector protrudes upward while holding an upper portion of the cylinder head oil-tight with respect to an external space;
A plurality of bearing portions corresponding to a plurality of cylinders that rotatably support the camshaft, a connecting portion that connects the bearing portions, and an insertion hole portion that is formed in the connecting portion and through which the injector is inserted; A cam holder placed and fixed on the upper surface of the head;
An elastic seal member disposed between the insertion hole of the cam holder and the injector;
The cylinder head is configured so that the vicinity of the outer periphery of the injector hole on the upper surface of the cylinder head and the vicinity of the outer periphery of the insertion hole on the lower surface of the cam holder face each other with an annular gap therebetween,
The seal member includes a seal body that is mounted between the inner peripheral surface of the insertion hole and the injector, a first seal portion that is formed on the inside of the seal body and is pressure-bonded to the injector, and a seal body. A second seal portion that extends downward and protrudes downward from the insertion hole and is crimped to the vicinity of the outer periphery of the injector hole on the upper surface of the cylinder head, and the diameter of the second seal portion is expanded by the compression deformation due to the crimping. And a third seal portion that is pressure-bonded to the inner peripheral surface of the insertion hole portion. 2. The cylinder head structure for a direct injection diesel engine according to claim 1, wherein the gap is formed by retreating the vicinity of the outer periphery of the insertion hole on the lower surface of the cam holder from the lower surface side to the upper end side of the cam holder.   An annular substrate having an L-shaped cross section that is adhered to the outer peripheral surface and the bottom surface of the seal body and fitted in the insertion hole portion is provided, and the third seal portion is provided below the annular substrate. The cylinder head structure for a direct injection diesel engine according to claim 1 or 2, wherein the second seal portion is provided below the three seal portions.   The direct-injection diesel engine cylinder head structure according to any one of claims 1 to 3, wherein the cam holder has a bearing portion and a connecting portion fastened to the cylinder head by a plurality of bolts.

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