Title of Invention

''AN IMPROVED TIMING BELT COVER SUPPORTING STRUCTURE FOR AN ENGINE''

Abstract

On the engine body 1, the timing belt cover 32 for covering the crank timing pulley, the cam timing pulley and the timing belt wound around these pulleys is mounted. By projecting the case 33 of the water pump 30 provided on the cylinder block 2 the bearing portion 34 for supporting the drive shaft 31 is formed. By inserting the bearing portion 34 in the opening 35 formed at the central portion of the timing belt cover 32 and being provided with the bush 38, the E-ring 36 is coupled with the annular groove 40 of the bearing portion 34. Since the central portion of the timing belt cover 32 is supported in the wide range with the E-ring and the bush 38, the vibration preventing effect is high to reduce the generation of the noise due to the vibration.

Full Text

A TIMING BELT COVER SUPPORTING STRUCTURE FOR AN ENGINE BACKGROUND OF THE INVENTION 1. Field of Invention The present invention relates to an improvement of a timing belt cover supporting structure for an engine. 2. Background of Related Art In a 4-cycle engine of a vehicle and the like, it has been what is adapted to drive a valve apparatus and an auxiliary mechanism and so on synchronously in accordance with a crank shaft by using a timing belt. In this type of engine, by winding a timing be'lt on each timing pulley provided on the crank shaft, a cam shaft and a driving shaft of an auxiliary mechanism projected from one end of an engine body, respectively, those apparatuses are rotated synchronously. In general, in an engine having a timing belt, on the engine body a timing belt cover for covering timing pulleys and timing belt is mounted for preventing foreign materials such as water and dusts from sticking. A timing belt cover supporting structure of conventional art is explained by referring to Figs. 7 and 8. As shown in Figs. 7 and 8, in one end of an engine body 1 in an axial direction of a crank shaft, on the crank shaft 3 projecting from a lower end of a cylinder block 2 and a cam shaft 5 of a valve apparatus projecting from a cylinder head 4 a crank timing pulley 6 and a cam timing pulley 7 are provided respectively. Further, above the cylinder block 2 a water pump 8 is mounted and its driving shaft 9 is projected and on that driving shaft 9 a pump pulley 10 is mounted. On the crank timing pulley 6, the cam timing pulley 7 and the pump pulley 10, a timing belt 11 is wound and an appropriate tension is applied to the timing belt 11 by a tension pulley 12 provided between the crank timing pulley 6 and the pump pulley 10. And, by the crank timing pulley 6, the cam timing pulley 7 and the pump pulley 10 are adapted to be rotated synchronously through the timing belt 11. On the cylinder block 2, an oil pump 28 and a water pump 8 a rib 13 is provided by projecting so as to surround the crank timing pulley 6. On the cylinder block 2 and the cylinder head 4, a back plate 14 to cover the back of the cam timing pulley 7 by extending from the upper portion of the cylinder block 12 to the upper portion of the cylinder head 4 is mounted with bolts 15. On the back plate 14, a flange 16 is formed so as to surround the cam timing pulley 7. And, both ends of the of the rib 13 formed on the cylinder block 2, the oil pump 28 and the water pump 8 and both ends of the flange 16 of the cylinder head 4 and the back plate 14 mounted on the cylinder head 4 are connected, thereby a series of cover connecting face 17 which surround the crank timing pulley 6, the cam timing pulley 7, the pump pulley 10, the tension pulley 12 and the timing belt 11 wound thereon is formed by the rib 13 and the flange 16. On this cover connecting face 17, a timing belt cover 18 made of synthetic resin is connected through a seal 18A to cover the crank timing pulley 6, the cam timing pulley 7, pump pulley 10, the tension pulley 12 and the timing belt 11 wound thereon. The timing belt cover 18 is mounted on the cylinder block 12 and the back plate 14 with a plurality of bolts 19 (merely two are shown) disposed along circumference of the cover connecting face 17. The crank shaft 3 is inserted into an opening 20 provided on the timing belt cover 18 and projected outward, and on the tip thereof a crank pulley 21 to drive auxiliary apparatuses for the engine (not shown) such as an alternator and an air compressor. A case 22 of water pump 8 is mounted on the cylinder block 2 by a plurality of bolts 24 inserted in mounting bosses 23. On one of the mounting bosses 23 of the case 22, a stud bolt 25 is provided in standing. This stud bolt 25 is adapted to be penetrated through approximately central portion of the timing belt cover 18, on tip end of which a flange nut 26 is screwed to support the timing belt cover 18. For reference, in Fig. 7, 27 shows a cylinder head cover, 28 shows an oil pump, and in Fig. 8, 29 designates an oil level gauge guide and 29A designates a stay to support the oil level gauge guide 29 by being clamped together with the timing belt cover 18 by a flange nut 26. Thus, by supporting the central portion of the timing belt cover 18 by screwing the flange nut 26 on the stud bolt 25 provided in standing in the case 22 of the water pump 8, a resonance of the timing belt cover 18 is prevented a noise from occurring. However, in the above mentioned timing belt cover supporting structure of the conventional engine, there have been the following problems. That is, in order to support the central portion of the timing belt cover 18, it is needed to screw the flange bolt 26 on the stud bolt 25 provided in standing, thereby the assembly process has become complicated. Further, since the area of the support portion of the timing belt cover 18 due to the flange nut 26 is small, a vibration controlling effect is low. In addition, since the timing belt 11 is necessary to be disposed for avoiding the stud bolt 25, a limitation for a layout is great. The present invention has been done in the light of the above problem, and one object of the present invention is to provide a support structure of a timing belt cover which is easy to be assembled and high in effect for controlling the vibration. SUMMARY OF THE INVENTION The first feature of a support structure for a timing belt cover according to the present invention resides in that, in an engine having a timing belt cover covering a timing belt, one portion of a case of an auxiliary apparatus mounted on an engine body by being disposed within a timing belt cover is projected, the projected portion of the case is inserted in an opening provided on an approximately central portion of the timing belt cover and extended outward, and the projected portion and the opening are coupled with each other. Thereby, the central portion of the timing belt cover is supported by the projected portion of the auxiliary apparatus mounted on the engine body. According to the second feature of the present invention, a support structure for a timing belt cover comprises, in the first feature of the present invention, an auxiliary apparatus is a water pump. Thereby, the central portion of the timing belt cover is supported by the projected portion of the water pump case. According to the third feature of the present invention, a drive shaft of the water pump of the the second feature is inserted in the projected portion and extended outward of the timing belt cover. Thereby, the water pump is driven from the outer side of the timing belt cover. According to the fourth feature of the present invention, in any feature of the above three features, the projected port'ion of the case and the opening of the timing belt cover are coupled by an E-ring. Thereby, the central portion of the timing belt cover is supported by the projected portion of the case of the auxiliary apparatus through the E-ring. According to the fifth feature of the present invention, a support structure for a timing belt cover resides, in any one of the above the first to third features, in that a groove formed on the projected portion of the case and a claw portion formed in the opening of the timing belt cover are engaged. Thereby, the central portion of the timing belt cover is supported by the projected portion through the engagement of the groove and the claw. According to the sixth feature of the present invention, an edge of the opening portion is provided with at least three snap hooks to engage with a projected portion of the auxiliary apparatus unremovably in a snap action and a resilient means is provided between the opening portion and the auxiliary apparatus. Thereby, the edge of the opening portion and projection may be securely engaged with each other to prevent a noise caused by vibration. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a vertically sectional side view of the mounting portion of the timing belt cover of the first embodiment of the present invention. Fig. 2 is a front view of the mounting portion of the timing belt cover shown in Fig. 1 in a partially broken manner. Fig. 3 is an enlarged front view of the E-ring to be used the support structure for the timing belt cover shown in Fig. 1. Fig. 4 is a vertically sectional side view of the main portion of the mounting portion of the timing belt cover of the second embodiment of the present invention. Fig. 5 is a vertically side view of the opening of the timing belt cover shown in Fig. 4. Fig. 6 is a front view of the opening of the timing belt cover shown in Fig. 4. Fig. 7 is a vertically sectional side view of a mounting portion of a conventional timing belt cover for an engine. Fig. 8 is a partially broken front view of a mounting portion of a conventional timing belt cover for an engine. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention are explained in detail based on the attached drawings. For reference, since the embodiments are approximately identical in the structure of the above conventional art except a structure of a water pump, a disposition of a tension pulley and a central supporting portion of the timing belt cover, identical portions which are depicted in Figs. 7 and 8 are indicated with the identical signs as well and different portions only are explained in detail. Now, the first embodiment of the present invention is explained referring to Figs. 1 to 3. As shown in Figs. 1 and 2, in an engine relating to the first embodiment, in a water pump 30 (auxiliary apparatus) mounted on a cylinder block 2, a drive shaft 31 thereof is extended out of a timing belt cover 32. And, a tip end of the drive shaft 31 is mounted with a pulley (not shown) and adapted to be driven together with other auxiliary apparatuses (not shown) such as an alternator and an air compressor through V-belt (not shown) by a crank pulley 21 of the crank shaft 3. A case 33 of the water pump 30 is formed in such a manner as a circumference around the drive shaft 31 is projected and, an approximately cylinder-like bearing portion 34 (projected portion) to support rotatably the drive shaft 31 inserted therein is formed. The bearing portion 34 is inserted in an opening 35 provided around at a central portion of the timing belt cover 32 connected with bolts 19 to a cover connecting face 17 of an engine body 1 and engaged with the opening 35 by an E-ring 36 (see Fig. 3). The tip end of the bearing portion 34 is provide with a stepped portion 37 and the outer circumference portion of the bearing portion 34 is coupled with an annular bush 38 made of resilient material such as gum which abuts to the stepped portion 37. The opening 35 of the timing belt cover 32 is coupled with the bush 38 and abuts to a stepped portion 39 formed on the outer circumference of the bush 38, and by being clamped between the E-ring 36 inserted in an outer groove 40 formed on the tip end of the bearing portion 34 and the stepped portion 39 of the bush 38, the opening 35 is engaged with the bearing portion 34. The operation thus constituted embodiment is explained next. The timing belt cover 32 is connected to the cylinder block 2 and the back plate 14 with a plurality of bolts 19 at its circumference, and is engaged with the bearing portion 34 of the water pump 30 through the E-ring 36 at its central portion, thereby it is mounted on the engine body 1. Since the central portion of the timing belt cover 32 is supported by the E-ring 36 and the bush 38 in a wide area, a vibration preventing effect is high to decrease the generation of noise due to the vibration. Since the opening 35 of the timing belt cover 32 is engaged with the gearing portion 34 of the water pump 30 by the E-ring 36, the timing belt cover 32 can be easily mounted on the engine body 1. Further, since the conventional stud bolts for supporting the central portion of the timing belt cover 32 become unnecessary, the limit on an layout of a timing belt 11 becomes small to increase the freedom of design. Next, the second embodiment of the present invention is explained referring to Figs. 4 to 6. For reference, since the constitution of the second embodiment is identical in general with the first embodiment except that the engagement structure between the opening of the timing belt cover and the bearing portion of the water pump is different, hereinafter, portions identical with what are indicated in Figs. 1 and 2 are attached by the identical signs and the explanation thereof is omitted, and the different portions only are explained. As shown in Fig. 4, in the engine of the second embodiment, the E-ring is omitted and the opening 35 is directly engaged with the bearing portion 34 of the water pump 30 through pawls 41 formed on the opening 35 of the timing belt cover 32. An outer circumference of the tip of the bearing portion 34 of the water pump 30 is provided with a stepped portion 42 and an annular groove 43 (groove portion). As shown in Figs. 5 and 6, the opening 35 of the timing belt cover 32 are provided with a plurality of pawls 41 (snap hooks) at an identical interval along the edge of the opening 35 (three pieces in Figs.)- One side of the pawl 41 is slanted and such slanted portion is pushed and spread at the time when the bearing portion 34 is inserted in the opening 35 by the tip end of the bearing portion 34 to engage with the annular groove 43 unremovably by a snap-action. And, between the stepped portion 42 of the bearing portion 34 and the stepped portion 44 of the opening 35, by interposing an annular bush 45 made of a resilient material such as gum, the pawl 41 is coupled with the annular groove 43 and the opening 35 and the bearing portion 34 are engaged with each other. By being thus structured, at the time of mounting the timing belt cover 32 on the engine body 1, while putting the opening 35 so as to fit to the bearing portion 34, near the central portion of the timing belt cover 32 is made to be pushed, the pawls 41 are pushed and opened by the tip end of the bearing portion 34 and engaged with the annular groove 43, and as a result the opening 35 is engaged with the bearing portion 34. Therefore, the timing belt cover 32 can be mounted easily on the engine body 1. Since the central portion of the timing belt cover 32 is engaged with the bearing portion 34 of the water pump 30 by the pawl 41 and supported by the pawl 41 and the bush 45 in a wide area, the vibration preventing effect is high and the generation of the noise due to the vibration is reduced. Incidentally, an engagement between the timing belt cover 32 and the bearing portion 34 is not limited to the pawl 41 and the annular groove 43. Instead of the groove 43, a projection, flange or the like which engages with the pawl 41 may be used. Further, as well as in the 1st embodiment, since the stud bolt for supporting the central portion of the timing belt cover 32 becomes unnecessary, the limit of the layout of the timing belt 11 becomes small and the freedom of the design can be made large. For reference, in the above first and second embodiments, the bearing portion of the case of the water pump is adapted to be engaged with the opening of the timing belt cover, but the present invention is not limited to these embodiments, for example, any case of an engine-auxiliary apparatus to be mounted on the engine body within the timing belt cover is made projected and inserted in the opening to engage it with the timing belt cover. Incidentally, since the bush 38,45 is provided for the purpose of engaging the edge of the opening 35 with the bearing portion 34, instead the bush 38,45, any resilient means such as spring may be used. According to the first feature of the present invention, since, by forming the projected case of the auxiliary apparatus which is mounted on the engine body to engage with the opening of the timing belt cover, the central portion of the timing belt cover is supported by the projected case of the auxiliary apparatus, the resonance of the timing belt cover due to the engine vibration is prevented to reduce the generation of the noise. Further, since the conventional stud bolts for supporting the central portion of the timing belt cover becomes unnecessary, the limit of the layout of the timing belt becomes small to increase the freedom of the design. According to the second feature of the present invention, by forming a projection on the case of the water pump, the central portion of the timing belt cover is supported by the projection of the water pump. According to the third feature of the present invention, since the drive shaft of the water pump is inserted in the projected portion and extended out of the timing belt cover, the water pump can be driven out of the timing belt cover. According to the fourth feature of the present invention, by engaging the projected portion of the case of the auxiliary apparatus with the opening of the timing belt cover through the E-ring, the central portion of the timing belt cover is supported by the projected portion of the case of the auxiliary apparatus. According to the fifth feature of the present invention, since the groove portion formed on the projected portion of the case of the auxiliary apparatus and the pawl formed on the opening of the timing belt cover are adapted to be engaged with each other, the central portion of the timing belt cover is supported by the projected portion of the case of the auxiliary apparatus through the engagement between the groove portion and the pawl. According to the sixth feature of the present invention, since an edge of the opening portion is provided with at least three snap hooks to engage with a projected portion of the auxiliary apparatus unremovably in a snap action and a resilient means is provided between the opening portion and the auxiliary apparatus, a vibration preventing effect may be increased to reduce a noise caused by a vibration. WHAT IS CLAIMED IS: 1. A timing belt cover supporting structure to cover the a timing belt in an engine comprises: a projected portion formed by projecting one portion of a case of an auxiliary apparatus disposed within the timing belt cover and mounted on an engine body, wherein the projected portion of the case is inserted in an opening provided approximately at the central portion of the timing belt cover and extended outward to make the projected portion and the opening engage. 2. A timing belt cover supporting structure according to Claim 1, wherein the auxiliary apparatus is a water pump. 3. A timing belt cover supporting structure according to Claim 2, wherein said a driving shaft of the water pump is inserted in the projected portion and extended out of the timing belt cover. 4. A timing belt cover supporting structure according to any one of Claims 1 to 3, wherein the projected portion of the case and the opening of the timing belt case are engaged with each other through the E-ring. 5. A timing belt cover supporting structure according to any one of Claims 1 to 3, wherein the groove portion formed on the projected portion of the case and the pawl formed on the opening of the timing belt cover are engaged with each other. 6. A timing belt cover supporting structure for engaging an auxiliary apparatus mounted on an engine body with a timing belt cover comprises at least three snap hooks which are provided on an edge of the opening portion to engage with a projected portion of the auxiliary apparatus in a snap-action unremovably and a resilient means between the timing belt cover and the auxiliary apparatus to prevent a noise caused by vibration. 7. A timing belt cover supporting structure substantially as herein described with reference to the accompanying drawings.

Documents:

346-del-1999-abstract.pdf

346-del-1999-claims.pdf

346-del-1999-correspondence-others.pdf

346-del-1999-correspondence-po.pdf

346-del-1999-description (complete).pdf

346-del-1999-drawings.pdf

346-del-1999-form-1.pdf

346-del-1999-form-13.pdf

346-del-1999-form-19.pdf

346-del-1999-form-2.pdf

346-del-1999-form-3.pdf

346-del-1999-form-4.pdf

346-del-1999-form-6.pdf

346-del-1999-gpa.pdf

346-del-1999-petition-138.pdf

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