JP3846473B2 - Cylinder head structure of overhead camshaft direct injection diesel engine - Google Patents

Description

  The present invention relates to a cylinder head structure of an overhead camshaft type direct injection diesel engine.

  2. Description of the Related Art Conventionally, a direct injection diesel engine that directly injects fuel into a combustion chamber has an injector penetrating from the upper part of the cylinder head toward the combustion chamber. For example, as shown in Patent Document 1, the injector is positioned at the lower end of the injector. The nozzle hole is disposed so as to face the combustion chamber, while the connector or the like located at the upper end is disposed so as to be exposed to the outside. In the invention described in Patent Document 1, a cam holder that rotatably supports a camshaft is disposed on the upper surface of a cylinder head, a part of the cam holder is covered with a cylinder head cover from above, and the remaining part is exposed to the outside. Exposed. That is, the valve head chamber space above the cylinder head is shielded from the external space by the cylinder head cover and a part of the cam holder. And it is set as the structure which exposes the upper end part of the injector to the exterior by forming the insertion hole of the injector in the part exposed to the exterior of the cam holder. Here, sealing between the inner peripheral surface of the insertion hole and the outer peripheral surface of the injector with an O-ring prevents water and dust from entering the injector hole of the cylinder head from the outside.

  However, in the invention described in Patent Document 1, since the injector holder for fixing the injector is disposed on the upper surface of the cylinder head, the injector holder is accommodated in the cylinder head cover. Therefore, if the injector is to be removed for maintenance or the like, the cylinder head cover needs to be removed once, resulting in poor workability.

As an improvement measure, for example, Patent Document 2 discloses a cylinder head portion structure in which the injector and the injector holder are exposed to the outside. In the invention described in Patent Document 2, the injector holder is disposed in a portion exposed to the outside of the upper surface of the cam holder. And it seals using the O-ring between the outer peripheral surface of this injector and the inner peripheral surface of an insertion hole. As a result, the injector holder is exposed to the outside of the cylinder head cover or the like, the workability such as removal of the injector is improved, and serviceability is improved.
Special Table 2000-515610 Japanese Patent Laid-Open No. 2001-115891

  By the way, when the injector is exposed to the outside, high sealing performance is required between the exposed portion and the injector hole. However, in the cylinder head structure disclosed in Patent Documents 1 and 2, both O-ring methods are employed in which an O-ring is arranged between the outer peripheral surface of the injector and the inner peripheral surface of the insertion hole. In this method, the seal pressure is determined by the relationship between the thickness of the O-ring and the groove depth of the ring mounting groove provided on the side surface of the injector. Therefore, the O-ring method has a limit in increasing the seal pressure.

  Furthermore, from the viewpoint of downsizing the engine and improving workability, a cam holder that supports the camshaft may be formed as a separate part from the cylinder head, and the cam holder may be mounted on the cylinder head. In this case, not only the injector hole of the cylinder head communicating with the insertion hole of the injector, but also the valve chamber space where the intake and exhaust valves and the like exist is located below the cam holder. For this reason, not only the injector hole but also intrusion of water or the like into the valve operating chamber space must be taken into consideration, and the place to seal becomes a problem.

  The present invention has been made in view of such a point, and the object of the present invention is to arrange the injector and the injector holder so as to be exposed to the outside of the cylinder head cover, and improve serviceability. The object is to ensure a reliable sealing performance without increasing the number of parts.

  The first invention is directed to a cylinder head portion structure of an overhead camshaft type direct injection diesel engine in which an injector is arranged upright on a cylinder head.

  An opening that opens on the upper surface of the cylinder head, and holds the upper portion of the cylinder head in an oil-tight manner from an external space, and an upper end portion of the injector that is inserted into the injector hole. A cylinder head cover having a projecting opening, and a lower surface of the cylinder head cover, which is placed on the upper surface of the cylinder head, abuts on an opening peripheral surface of the injector hole, and a sealing surface with the opening on the upper surface. A cam holder that supports the cam shaft, an injector holder that is disposed on the cam holder and that presses and fixes the injector downward by a pressing arm, and a space between the injector and the cam holder. And a sealing member for sealing.

Each of the cam holders is formed at the exposed portion thereof, the holder mounting surface to which the injector holder is mounted, the insertion hole communicating with the injector hole, and the upper end portion of the insertion hole. A seal receiving portion for receiving the seal member ; and a holder fixing bolt hole through which a holder fixing bolt for fixing the injector holder passes .

  Further, the injector includes a holder abutting surface with which a pressing arm of the injector holder abuts, and a seal pressing surface that presses the seal member disposed in the seal receiving portion below the holder abutting surface. And.

Furthermore, the cylinder head has a screw hole in which a tip of the holder fixing bolt is screwed into the middle deck, and a part of the holder fixing bolt is a valve chamber space between the cam holder and the middle deck. On the other hand, the head of the holder fixing bolt is exposed to the outside of the cylinder head cover, is externally inserted into the holder fixing bolt, and seals between the upper surface of the cam holder and the outer peripheral surface of the holder fixing bolt. A bolt seal member is further provided, and the bolt seal member has a cylindrical portion loosely fitted on the outer peripheral surface of the shaft portion of the holder fixing bolt and a flange portion extending outward from one end portion of the cylindrical portion, The flange is provided with a first seal ring that contacts the upper surface of the cam holder, and the other end of the cylindrical portion has an inner peripheral surface of the holder fixing bolt hole and an outer periphery of the shaft portion of the holder fixing bolt. A second seal ring is provided for sealing between the two and the holder fixing bolt is fastened to press the seal member and the bolt seal member from above.

  In the case of the above configuration, the cam holder that supports the camshaft is mounted on the upper surface of the cylinder head. When the cylinder head cover is attached from above the cylinder head, the valve chamber space, which is a space surrounded by the middle deck of the cylinder head and the cylinder head cover, is shielded from the external space. Here, the middle deck is an intermediate wall that partitions the water jacket and the valve operating chamber space in the cylinder head.

  The opening of the cylinder head cover is in contact with the seal surface of the cam holder. As a result, the exposed portion of the cam holder surrounded by the seal surface is exposed to the outside of the cylinder head cover through the opening.

  The exposed portion is formed with an insertion hole communicating with the injector hole and a holder mounting surface for mounting the injector holder. The injector inserted into the insertion hole and the injector hole is exposed outside the cylinder head cover at the exposed portion. At the same time, the injector holder that fixes the injector is also exposed to the outside of the cylinder head cover by being attached to the holder mounting surface. This makes it possible to remove the injector without removing the cylinder head cover.

  Then, the holder abutting surface of the injector is pressed by the pressing arm of the injector holder, and is pressed and fixed downward. A seal pressing surface is provided below the holder contact surface, and the seal member disposed in the seal receiving portion formed at the upper end portion of the insertion hole is sandwiched between the seal pressing surface and the seal receiving portion. Is done. Thereby, the pressing force from above by the injector holder becomes an axial force and acts on the seal member via the seal pressing surface. Therefore, if the pressing force by the injector holder is increased, the pressing force on the seal member is also increased, and the sealing pressure is sufficiently large compared to the conventional structure in which the injector and the insertion hole are sealed with an O-ring. Is secured.

  As described above, the injector holder not only fixes the injector, but also has a role of securing a sealing pressure of a seal member located between the injector and the cam holder.

  Further, since the cam holder is mounted on the cylinder head, the seal of the path from the insertion hole to the valve operating system on the side of the injector hole through the contact surface between the lower surface of the cam holder and the upper surface of the cylinder head However, since the seal member seals between the injector and the insertion hole in the seal receiving portion that is above the lower surface of the cam holder, water and foreign matter may enter the valve system. Is prevented.

Further, in the case of the above configuration, the holder fixing bolt for fixing the injector holder passes through the holder fixing bolt hole formed in the cam holder and is screwed into the screw hole formed in the middle deck of the cylinder head. Thus, the injector holder is not directly fixed to the cylinder head via the cam holder, but is directly fixed to the cylinder head. Although the reaction force of the injector that injects high-pressure fuel is considerably large, the injector is fixed with sufficient strength by fixing the injector holder to the cylinder head.

  Further, in this configuration, the injector holder is exposed to the external space, and a part of the bolt is exposed to the valve operating chamber space between the cam holder and the middle deck. At the same time, a gap is generated between the inner peripheral surface of the bolt hole of the cam holder and the outer peripheral surface of the bolt. Therefore, water or dust may be mixed from the external space through the gap, or engine oil or the like in the valve operating chamber space may leak into the external space.

  Therefore, a bolt seal member is disposed between the upper surface of the cam holder and the outer peripheral surface of the holder fixing bolt. By disposing the bolt seal member at this position, it is possible to seal the path through which water, engine oil, and the like travel along the cam holder and the path along the outer peripheral surface of the holder fixing bolt. That is, the seal of the gap between the injector holder and the cam holder is of course, for example, the head of the holder fixing bolt is exposed to the external space, and water or the like is exposed from the gap between the head of the holder fixing bolt and the injector holder. Can be prevented from entering or conversely flowing out of the engine oil from the gap. In this way, the sealing performance around the holder fixing bolt is secured.

Therefore, in the first invention, the exposed portion of the cam holder is exposed from the cylinder head cover to the external space, and the injector and the injector holder are disposed in the exposed portion, thereby ensuring the serviceability of the injector. On the other hand, by providing a seal member between the seal pressing surface of the injector and the seal receiving portion of the cam holder, and applying a pressing force from above to the seal member by the injector holder, not only the injector hole, The sealability of the system can be sufficiently secured. In addition, since the seal pressure is increased by the injector holder for fixing the injector, the number of parts does not increase.

A second invention is the first invention according to the first invention , wherein the engine is a multi-cylinder double overhead camshaft type direct injection diesel engine in which two camshafts are provided on a cylinder head, and the opening of the cylinder head cover is A slit located between the two camshafts and extending in the longitudinal direction of the cylinder head, wherein the injector is provided for each cylinder, arranged in the longitudinal direction of the slit, and the injector holder is Suppose that each of the injectors is arranged and arranged in the longitudinal direction of the slit.

  In the case of the above configuration, the opening of the cylinder head cover is a slit that is located between the two camshafts and extends in the longitudinal direction of the cylinder head, and the injectors and the injector holders in the slits. Are aligned in the longitudinal direction of the slit. For this reason, the injector holder and the injector are compactly arranged in a space-saving space between the two shafts.

According to a third invention , in the first or second invention , a concave groove is formed on at least one of the opening peripheral surface of the injector hole and the lower surface of the cam holder so as to surround the opening of the injector hole. Shall.

  In the case of the above configuration, even if water or the like enters between the lower surface of the cam holder and the peripheral surface of the injector hole opening through the injector and the insertion hole of the cam holder, the water or the like passes through the injector hole. Since it remains in the recessed groove provided so as to surround, water or the like can be prevented from entering the valve chamber space.

  According to the present invention, at the exposed portion of the upper surface of the cam holder, the injector is pressed and fixed from above by the injector holder, and at the same time, a sealing pressure is applied to the seal member disposed between the injector and the cam holder by the pressing force. As a result, the injector can be exposed and disposed outside the cylinder head cover to improve serviceability and to ensure a reliable sealing performance of the injector attachment without increasing the number of parts.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a plan view showing a cylinder head portion structure of an overhead camshaft type direct injection diesel engine E according to an embodiment of the present invention. The engine E has four cylinders S, S,. (See FIG. 4) is an in-line four-cylinder engine arranged in parallel. An injector 4 for injecting fuel directly into each cylinder S is inserted into each cylinder S from above the cylinder head 2.

  In the present embodiment, for convenience of explanation, the longitudinal direction of the engine E is the front-rear direction of the engine E, and the side of the engine E where the timing pulley (not shown) is located (the right side in FIG. 1) is the front side of the engine E. The opposite side (left side in FIG. 1) is called the rear side of the engine. Further, the left-right direction (vertical direction in FIG. 1) perpendicular to the front-rear direction of the engine E is referred to as the width direction of the engine E.

  2 is a cross-sectional view showing the configuration of the cylinder head 2 with the injector 4 as the center when viewed from the front of the engine E. FIG. 3 shows the engine E with the cylinder head cover 1, the injectors 4, 4,. 2 is a plan view showing a cylinder head portion structure of an engine E. FIG.

  Reference numeral 1 denotes a cylinder head cover, which is attached to the cylinder head 2 from above, and a slit 11 as an opening extending in the cylinder row direction is formed at the approximate center of the head cover 1.

  On the other hand, as shown in FIGS. 2 and 3, two camshafts 6, 6 extending in the front-rear direction of the engine E are disposed above the cylinder head 2, and the camshafts 6, 6 are connected to the cylinder head 2. Is rotatably supported by a cam holder 3 mounted on the upper surface of the cam. The cam holder 3 is formed with a groove portion 32a as an exposed portion exposed to the outside from the slit 11 when the head cover 1 is attached, and the groove portion 32a has an insertion hole 36 for inserting the injector 4. Is formed.

  The injector 4 is inserted into the insertion hole 36 and fixed by the injector holder 5 as shown in FIGS. The injector 4 is supported upright on the cylinder head 2 along the center line of each cylinder S, and the upper end portions of the four injectors 4 are exposed to the outside of the cylinder head cover 1 from the slits 11. At this time, as shown in FIGS. 2 and 8, a seal member 7 is disposed in the insertion hole 36 between the injector 4 and the cam holder 3.

  More specifically, as shown in FIGS. 2, 4, and 8, the cylinder head 2 includes a middle deck 21 that defines a valve chamber space 8 in which a water jacket 24 and a swing arm (not shown) are disposed. And four boss portions 23 projecting upward from the middle deck 21 are formed at predetermined intervals in the front-rear direction of the engine E. The boss portions 23 are formed with injector holes 22, 22,... Into which the injectors 4, 4,. Each injector hole 22 is recessed vertically downward coaxially with the central axis of each cylinder S. A narrow groove 22b is formed on the boss upper end surface 23a of the boss portion 23, which is the peripheral surface of the upper end opening of each hole 22, so as to surround the upper end opening of the hole 22. Here, the surface formed by the boss upper end surface 23a is referred to as the upper surface of the cylinder head 2.

  Further, a bolt screw hole 27 into which a holder fixing bolt 55 described later is screwed is formed on the rear side of each injector hole 22 in the middle deck 21 of the cylinder head 2.

  A peripheral wall portion 25 extending upward from the middle deck 21 is integrally formed on the outer peripheral edge of the cylinder head 2 over the entire circumference, and the upper end surface of the peripheral wall portion 25 is a first seal surface 26. ing.

  As shown in FIGS. 3 and 5, the cam holder 3 includes a main body portion 32 formed so as to extend in the front-rear direction of the engine E, and a cam journal that branches off from the middle of the main body portion 32 in the width direction of the engine E. It consists of parts 33, 33,. And cam caps 34, 34,... Are attached to the upper portions of the cam journal portions 33, 33,.

  That is, the main body portion 32 and the cam journal portions 33, 33,... Are integrally formed, and when the cam holder 3 is placed on the upper surface of the cylinder head 2, as shown in FIGS. The lower surface of the main body 32 abuts on the boss upper end surface 23a (see FIG. 2). The groove portion 32a is formed in the main body portion 32 so as to open on the upper surface over substantially the entire longitudinal direction. In the main body portion 32, the cylinder head cover 1 is formed on the upper surface of the standing wall that defines the groove portion 32a. The third seal surface 32b is in contact with.

  In the groove portion 32a, four injector insertion holes 36 penetrating the bottom portion in the vertical direction are formed in the front-rear direction of the engine E at a predetermined interval. Each injector insertion hole 36 communicates with the injector hole 22 when the cam holder 3 is attached to the cylinder head 2.

  A seal receiving portion 36 a that receives the seal member 7 is formed at the upper end portion of the injector insertion hole 36. The seal receiving portion 36a is a round hole having a flat bottom surface and having a diameter larger than that of the insertion hole.

  The groove 32a has a holder fixing bolt hole 37 through which a bolt 55 for fixing the injector holder 5 passes, and a holder mounting surface 38 for mounting the injector holder 5, on the rear side of each injector insertion hole 36. Are formed in order. A pin fitting hole 38a for positioning the injector holder 5 is formed in the holder mounting surface 38.

  As shown in FIG. 3, in the cam holder 3, the cam journal portions 33 and 33 and the cam cap 34 closest to the timing pulley (not shown) located at the front end portion of the engine E are closer to the first seal surface 26. A second seal surface 35 that protrudes upward and is continuous with the first seal surface 26 is provided.

  As shown in FIG. 2, the cylinder head cover 1 has a substantially box shape with a lower opening, and the lower end surface of the peripheral wall portion 12 has a first seal surface of the cylinder head 2 extending over the entire circumference. A first seal portion 12 a that abuts on 26 is provided. Further, the peripheral wall portion 12 on the front end side of the engine E of the cylinder head cover 1 is not shown so as to be in contact with the second seal surface 35, although illustration is omitted.

  Further, as described above, the slit 11 having an opening in the longitudinal direction is formed at the approximate center of the cylinder head cover 1. The peripheral edge of the slit 11 is inclined so as to be gradually lowered toward the inner side of the slit 11, and an extending portion 11a extending further downward from the lower end thereof is formed on the entire circumference of the slit 11. It is formed in an annular shape. A third seal portion 11b that contacts the third seal surface 32b of the cam holder main body portion 32 is provided on the lower end surface of the extension portion 11a.

  By mounting the cylinder head cover 1 on the cylinder head 2 on which the cam holder 3 is mounted, the first seal portion 12a of the cylinder head cover 1, the first seal surface 26 of the cylinder head 2, and the pulley side cam holder 3 2 The seal surface 35 comes into contact. On the other hand, the third seal portion 11b of the slit 11 opened substantially at the center of the cylinder head cover 1 and the third seal surface 32b of the cam holder main body portion 32 abut. As a result, the valve operating chamber space 8 which is a space surrounded by the middle deck 21, the peripheral wall portion 25 and the cylinder head cover 1 of the cylinder head 2 is shielded from the external space and is kept oiltight. At this time, in the slit 11, the groove 32a located inside the slit 11 is exposed to the external space.

  Next, a support structure for the injector 4 in the groove 32a exposed to the external space will be described. The injector 4 passes through the injector insertion hole 36 of the cam holder main body 32 from above the cylinder head 2 and is inserted into the injector hole 22 of the cylinder head 2. The injector 4 is pressed and fixed from above by the injector holder 5. At this time, the seal member 7 is interposed between the injector 4 and the cam holder main body 32.

  As shown in FIG. 6, the injector 4 has a cylindrical shape as a whole, and a narrow neck portion 41 is formed in the middle in the longitudinal direction so as to be recessed so that the cross section is substantially rectangular. A flange 42 is formed at the lower end of the narrow neck portion 41. The upper end surface of the flange 42 is a holder abutting surface 43, 43 on which arm portions 51, 51 of an injector holder 5, which will be described later, abuts, and the lower end surface is a seal pressing surface 44 that presses the seal member 7.

  As shown in FIGS. 2, 7, and 8, the injector holder 5 is formed with two arm portions 51 and 51 that are divided into two forks as pressing arms on the distal end side in the longitudinal direction. A contact surface 52 that contacts the holder mounting surface 38 of the cam holder main body 32 is formed on the lower surface of the rear end side. The contact surface 52 is curved upward toward the rear end. Further, a positioning pin 53 projects downward near the rear end of the corresponding contact surface 52. The positioning pin 53 is fitted into the pin fitting hole 38a of the cam holder main body 32. A bolt insertion hole 54 through which a holder fixing bolt 55 for fastening the holder 5 to the cylinder head 2 passes is formed at a substantially central portion.

  As shown in FIGS. 2 and 8, while the injector 4 is inserted into the insertion hole 36 and the injector hole 22, the contact surface 52 of the injector holder 5 is brought into contact with the holder mounting surface 38 of the groove 32a. Then, the positioning pin 53 is fitted into a pin fitting hole 38a provided in the holder mounting surface 38. Thus, the arm portions 51 and 51 are brought into contact with the holder contact surfaces 43 and 43 of the injector 4. Then, the holder fixing bolt 55 is passed through the bolt insertion hole 54 and the holder fixing bolt hole 37 located at the center of the holder 5, and the bolt 55 is screwed into the bolt screw hole 27 provided in the middle deck 21. As a result, a downward pressing force acts on the holder contact surfaces 43 and 43 from the arm portions 51 and 51 with the corresponding contact surface 52 as a fulcrum, and the injector 4 is fixed.

  At this time, the seal member 7 is disposed in the seal receiving portion 36a of the groove portion 32a, and the seal member 7 is sandwiched between the seal pressing surface 44 of the injector 4 and the bottom surface of the seal receiving portion 36a. The The seal member 7 is a rubber-shaped cross-sectional square annular body. The inner diameter is a dimension that can be loosely fitted to a cylindrical portion located directly below the flange 42 of the injector 4, and the outer diameter is a dimension that can be loosely fitted to the seal receiving portion 36a of the cam holder 3. In this embodiment, in order to enhance the sealing performance by the seal member 7, the outer diameter is expanded and deformed in the radial direction when the seal member 7 is pressed toward the seal receiving portion 36a by the seal pressing surface 44. The outer peripheral surface has such a size that it abuts against the inner peripheral wall of the seal receiving portion 36a.

  Here, when the injector holder 5 is fixed, the injector holder 5 swings by a width that presses the seal member 7 with the contact surface 52 as a fulcrum. For this reason, positioning in the swinging contact portion is usually performed by providing a hemispherical body that protrudes from the injector holder 5, while providing a hemispherical hole that is recessed in the cam holder main body 32 and fits into the hemispherical body. Is done by. However, since the swinging width of the holder 5 is small, its positioning can also be performed by a positioning pin and a pin fitting hole. Here, by providing the positioning pin 53 and the pin fitting hole 38a, Compared with the case where a hemisphere is provided, the manufacturing cost can be reduced.

  Further, by providing the positioning pin 53 on the rear end side with respect to the contact surface 52 of the holder 5, the distance between the injector 4 and the positioning pin 53 with which the arm portions 51 and 51 contact is increased, and the positioning pin 53 Or the influence of the manufacturing error of the pin fitting hole 38a can be reduced.

  As shown in FIG. 8, a washer 56 as a bolt seal member is externally inserted into the bolt 55. As shown in FIG. 9, the washer 56 includes a cylindrical portion 56a that is loosely fitted on the outer peripheral surface of the shaft portion of the bolt 55, and a flange portion 56b that extends outward from one end portion of the cylindrical portion 56a. The flange portion 56b is integrally provided with a first rubber seal ring 56c by, for example, vulcanization, and the second end portion of the cylindrical portion 56a is similarly provided with a second rubber ring. A seal ring 56d is provided.

  Thus, each injector 4 is fixed by the injector holder 5, but in the longitudinal direction of the groove 32a of the cam holder main body 32, a holder fixing bolt hole 37 and a holder mounting surface 38 are provided on the rear side of each injector insertion hole 36. Since the injector holders 5 are formed in order, the injector holders 5 are arranged in parallel with the injectors 4 along the longitudinal direction of the groove 32a.

  In the case of the configuration described above, the cylinder head cover 1 is attached to the cylinder head 2 so that the valve chamber space 8 on the upper surface of the cylinder head 2 is oil-tightly sealed from the external space, and the cylinder head cover The groove 32a of the cam holder 3 surrounded by the slit 11 is exposed to the external space.

  The groove 32a exposed to the outside from the cylinder head cover 1 is formed with the injector insertion hole 36, the holder fixing bolt hole 37, and the holder mounting surface 38, and both the injector 4 and the injector holder 5 are the cylinder head cover. Since it is exposed to the outside of 1, the injector 4 can be attached and detached without removing the cylinder head cover 1, thereby improving serviceability.

  The injector 4 is fixed on the groove 32a of the cam holder main body 32 from above the cylinder head 2 by the injector holder 5. At this time, the seal member 7 is sandwiched between the seal pressing surface 44 of the injector 4 and the seal receiving portion 36a of the cam holder main body portion 32. Therefore, the pressing force from above the holder 5 becomes an axial force and acts on the seal member 7, and the seal pressure of the seal member 7 is secured. Then, by increasing the pressing force of the injector holder 5, the surface pressure applied to the seal member 7 can be increased, and the sealing performance can be made more reliable.

  Further, the seal member 7 is loosely fitted between the injector 4 and the seal receiving portion 36a. By receiving a downward pressing force from the seal pressing surface 44 of the injector 4, the radial direction of the seal member 7 It expands and deforms. As a result, not only the seal pressing surface 44 and the upper end surface of the seal member 7, and the lower end surface of the seal member 7 and the bottom surface of the seal receiving portion 36a, but also the outer peripheral surface of the seal member 7 and the inner peripheral surface of the seal receiving portion 36a. And the contact area expands.

  That is, the holder 5 secures the sealability between the injector 4 and the cam holder main body 32 at the same time as fixing the injector 4 to the cylinder head 2, and a new structure for applying a surface pressure to the seal member 7 Or it is not necessary to provide a member separately.

  Since the injector holder 5 has the bifurcated arms 51, 51, the injector 4 fixed to the holder 5 is prevented from rotating around the axis of the injector 4, and the axis around the axis. Is positioned. When the injector 4 is a multi-hole type, positioning around the axis is necessary, but positioning is easy.

  Further, the upper surface of the flange 42 formed on the injector 4 is an arm receiving surface 43, the lower surface is a seal pressing surface 44, and each surface 43, 44 is formed as one member, thereby each surface 43, It is not necessary to provide a separate member having 44 separately.

  Further, since sealing is performed at the seal receiving portion 36a located on the upper surface of the cam holder main body portion 32, a path for water and the like to enter the injector hole 22 from the outer space, and the cam holder main body portion 32 through the injector insertion hole 36. It is possible to seal two intrusion paths in one place, the path that travels between the lower surface and the boss upper end surface 23a at the upper end of the injector hole 22 and enters the valve operating chamber space 8.

  On the other hand, the holder fixing bolt 55 is exposed to the valve operating chamber space 8 between the cam holder 3 and the middle deck 21, and the fixing bolt 55 is fixed to the bolt insertion hole 54 of the injector holder 5 and the holder of the cam holder 3. The bolt hole 37 is penetrated. Therefore, the engine oil may leak from the valve chamber space 8 to the outside of the cylinder head cover 1 through the shaft portion of the bolt 55, and conversely, water or the like may enter the valve chamber space 8 from the outside. There is. However, by disposing a washer 56 extrapolated to the shaft portion of the bolt 55 between the injector holder 5 and the cam holder 3, the gap between the bottom surface of the groove portion 32a and the lower surface of the flange portion 56b of the washer 56 (up and down Direction gap) is sealed by the first seal ring 56c, and between the inner peripheral surface of the holder fixing bolt hole 37 and the outer periphery of the shaft portion of the bolt 55 (gap in the left-right direction in the figure) is the second seal ring. Sealed by 56d. As a result, a seal between the outer peripheral surface of the holder fixing bolt 55 and the cam holder 3 is secured.

  In the present embodiment, the head of the holder fixing bolt 55 is exposed to the external space. However, the second seal ring 56d of the washer 56 prevents water or the like from entering through the gap between the head of the bolt 55 and the injector holder 5, and prevents engine oil from flowing out.

  Further, in the groove portion 32a of the cam holder main body 32, a holder fixing bolt hole 37 is provided in parallel along the longitudinal direction of the groove portion 32a on the rear side of each injector insertion hole. For this reason, the holder 5 is aligned and disposed on one side in the longitudinal direction of the groove 32a, and the injector holder 5 and the injector 4 are compactly disposed in a space-saving space between the two shafts.

  In addition, this invention is not limited to the said embodiment, It includes other various embodiment. That is, in the above embodiment, a DOHC (double overhead camshaft) type engine in which two camshafts 6 and 6 are arranged on the upper part of the cylinder head 2 is an object, but a single camshaft is a SOHC. (single overhead camshaft) type engine may be targeted.

  In the above embodiment, not only the sealing performance of the seal pressing surface 44 of the injector 4 and the upper end surface of the seal member 7 and the lower end surface of the seal member 7 and the bottom surface of the seal receiving portion 36a, but also the seal member The sealing property between the outer peripheral surface of 7 and the inner peripheral surface of the seal receiving portion 36a is also ensured. However, if the sealing property between the seal pressing surface 44 and the upper end surface of the sealing member 7 and the sealing property between the lower end surface of the sealing member 7 and the bottom surface of the seal receiving portion 36a are ensured, the injector The sealing property between 4 and the insertion hole 36 is ensured.

  Furthermore, in the above-described embodiment, the injector holder 5 has the two arm portions 51 and 51 divided into the forked shape at the tip, but is not limited to such a shape, for example, one As long as it is possible to press and fix the injector 4 downward, such as only an arm portion, those having various shapes can be adopted.

1 is a plan view showing an in-cylinder direct injection diesel engine according to an embodiment of the present invention as viewed from above. It is sectional drawing which shows the structure of a cylinder head centering | focusing on an injector seeing from the engine front. It is a top view which shows a structure of a cylinder head by removing a cylinder head cover and omitting a swing arm or the like. FIG. 4 is a view corresponding to FIG. 3 illustrating a configuration of a middle deck of a cylinder head by removing a cam shaft and a cam holder. It is a component diagram which shows the structure of a cam holder. It is component drawing which shows an injector. It is a bottom view of an injector holder. It is sectional drawing which shows the structure of a cylinder head centering | focusing on an injector seeing from the engine side. FIG. 4 is a bottom view (a) and a cross-sectional view (b) taken along the line AA in FIG.

Explanation of symbols

1 Cylinder head cover
11 Slit (opening)
2 Cylinder head
21 Middle deck
22 Injector hall
22b Narrow groove (concave groove)
23a Boss top surface (periphery peripheral surface)
27 Bolt screw hole
3 Cam holder
32a Groove (exposed part)
32b Third seal surface (seal surface)
36 Insertion hole
36a Seal receiving part
37 Holder fixing bolt hole
38 Holder mounting surface
4 Injector
43 Holder contact surface
44 Seal pressing surface
5 Injector holder
51 Arm (holding arm)
54 Bolt insertion hole
55 Holder fixing bolt
56 Washer (Bolt seal member)
6 Camshaft
7 Seal material
8 Valve room space
E engine
S cylinder

Claims (3)

A cylinder head part structure of an overhead camshaft type direct injection diesel engine in which a camshaft is disposed on the cylinder head and an injector is disposed upright on the cylinder head,
An opening in the upper surface of the cylinder head, and an injector hole into which the injector is inserted;
A cylinder head cover having an opening in which an upper end portion of the injector inserted into the injector hole is protruded and disposed while oil-tightly holding an upper portion of the cylinder head from an external space;
Mounted on the upper surface of the cylinder head, the lower surface of the cylinder head comes into contact with the peripheral surface of the opening of the injector hole, and the upper surface of the cylinder head is surrounded by a sealing surface for the opening of the cylinder head cover. A cam holder for supporting the camshaft, having an exposed portion exposed to the outside of the head cover;
An injector holder disposed on the cam holder and pressing and fixing the injector downward by a pressing arm;
A seal member for sealing between the injector and the cam holder,
The cam holder is formed on the exposed portion, the holder mounting surface to which the injector holder is attached, the insertion hole that communicates with the injector hole, and the upper end portion of the insertion hole that opens upward. A seal receiving portion for receiving the seal member, and a holder fixing bolt hole through which a holder fixing bolt for fixing the injector holder passes ,
The injector includes a holder contact surface with which a pressing arm of the injector holder contacts, a seal pressing surface that presses the seal member disposed on the seal receiving portion below the holder contact surface, and Have
The cylinder head has a screw hole into which a tip of the holder fixing bolt is screwed to the middle deck,
While a part of the holder fixing bolt is exposed to the valve operating chamber space between the cam holder and the middle deck,
The head of the holder fixing bolt is exposed to the outside of the cylinder head cover,
A bolt seal member that is extrapolated to the holder fixing bolt and seals between the upper surface of the cam holder and the outer peripheral surface of the holder fixing bolt;
The bolt seal member has a cylindrical portion loosely fitted on the outer peripheral surface of the shaft portion of the holder fixing bolt, and a flange portion extending outward from one end portion of the cylindrical portion, and the cam holder includes the cam holder A first seal ring that contacts the upper surface is provided, and a second seal ring that seals between the inner peripheral surface of the holder fixing bolt hole and the outer periphery of the shaft portion of the holder fixing bolt is provided at the other end of the cylindrical portion. And
The cylinder head structure , wherein the seal member and the bolt seal member are pressed from above by fastening the holder fixing bolt . In the cylinder head part structure according to claim 1 ,
The engine is a multi-cylinder double overhead camshaft direct injection diesel engine with two camshafts on a cylinder head,
The opening of the cylinder head cover is a slit located between the two camshafts and extending in the longitudinal direction of the cylinder head,
The injector is provided for each of the cylinders, and aligned with the longitudinal direction of the slit,
The cylinder head structure according to claim 1, wherein the injector holder is provided for each injector and is aligned in the longitudinal direction of the slit. In the cylinder head structure according to claim 1 or 2 ,
A cylinder head part structure, wherein a concave groove is formed in at least one of an opening peripheral surface of the injector hole and a lower surface of the cam holder so as to surround the opening of the injector hole.

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