JPH11343922A - Cover structure of horizontal mounted engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep reliability of a belt transmission mechanism by controlling the temperature rise in a housing space without increasing the contour dimensions. SOLUTION: A front cover (C) is constructed of a seal plate 6 overlapped on the front surface of the engine, and belt covers connected to the seal plate 6. An opening portion for ventilation 69 is provided in the vertically extended portion adjacent to a cam pulley 36 in the inner circumferential side wall portion 65 of the seal plate 6 which surrounds an engine mount, and a sound insulation cover 20 is provided to cover the front cover (C) over the opening portion for ventilation 69.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt transmission mechanism for driving a valve operating system camshaft or an auxiliary machine of an engine mounted horizontally on a vehicle by a crankshaft via a timing belt. In the technical field related to a cover structure to be accommodated in a front cover.

[0002]

2. Description of the Related Art Conventionally, as a cover structure of this type of horizontally mounted engine, for example, as disclosed in Japanese Patent Application Laid-Open No. 8-326550, the engine is mounted horizontally so that a crankshaft extends in the left-right direction of the vehicle. A front cover having a substantially annular housing space arranged so as to surround an engine mount member for supporting the engine is provided at one end in the vehicle left-right direction of the diesel engine, and a belt transmission mechanism is housed in the housing space. It has been known.

In this device, the belt transmission mechanism, that is, a cam pulley on a valve system cam shaft, a pump pulley of a fuel injection pump (auxiliary machine) arranged adjacent to the cam pulley, and these pulleys are drivingly connected to a crank pulley. Since the timing belt and the like which are to be mounted are housed in the housing space in a substantially sealed state, it is possible to prevent the timing belt and the pulley from being deteriorated due to adhesion of rainwater or the like, and the occurrence of tooth skipping can be prevented.

[0004]

However, on the other hand,
In the above-mentioned conventional cover structure, since the housing space in the front cover is substantially sealed, heat from the engine or heat generated by the timing belt or the like is trapped in the housing space, so that the ambient temperature is likely to be high. Thermal deterioration of the timing belt and the like may be accelerated, and the reliability of the belt transmission mechanism may be impaired. In particular, in a diesel engine, since a driving load of a fuel injection pump having a high fuel discharge pressure is large, a problem due to thermal deterioration of a timing belt or the like is remarkable.

On the other hand, it is conceivable to increase the volume of the housing space or provide cooling fins on the front cover to alleviate the temperature rise in the housing space. Inevitably increase.

The present invention has been made in view of the above points, and an object of the present invention is to devise the shape and structure of a front cover for accommodating a belt transmission mechanism so that the outer dimensions of the front cover can be improved. The object is to maintain the reliability of the belt transmission mechanism by suppressing the increase in the temperature of the storage space without increasing the temperature.

[0007]

In order to achieve the above object, according to a solution of the present invention, in an engine horizontally mounted on a vehicle, a front cover accommodating a belt transmission mechanism has an annular cover surrounding an engine mount member. Paying attention to the fact that the inner peripheral side wall portion is provided, an opening for ventilation was provided in the inner peripheral side wall portion.

More specifically, according to the first aspect of the present invention, an engine mount for supporting the engine is provided at one end in the crankshaft direction of an engine mounted horizontally so that the crankshaft extends in the left-right direction of the vehicle. A front cover having therein a substantially annular housing space disposed so as to surround the engine mount member, wherein the housing space includes a crank pulley including a timing pulley on a crankshaft; A cover structure of a horizontally mounted engine that houses a cam pulley composed of a timing pulley on a camshaft, an auxiliary pulley composed of a timing pulley on an input shaft of an auxiliary machine, and a timing belt for drivingly connecting these pulleys. Is assumed. An inner peripheral side wall extending substantially parallel to the crankshaft direction of the engine is formed on an inner peripheral side of the front cover on the side of the engine mount member, and the cam pulley or the auxiliary pulley is formed of the inner peripheral side wall. An upper cover member provided with a ventilation opening for introducing outside air into the accommodation space at a portion proximate to one of the above and extending vertically, and covering at least the ventilation opening from above the front cover. Is provided.

According to this structure, the outside air can be introduced into the accommodation space for accommodating the timing belt and the timing pulley through the ventilation opening provided in the inner peripheral side wall of the front cover, so that the outer dimensions of the front cover can be increased. In addition, it is possible to suppress an increase in the ambient temperature of the belt transmission mechanism including the timing belt and the pulley in the accommodation space, and to prevent a reduction in the reliability of the belt transmission mechanism due to the temperature increase.

In addition, since the ventilation opening is provided in a vertically extending portion of the inner peripheral side wall and the upper cover member is provided above the ventilation opening, for example, a dripping from a hood of a vehicle is performed. It is possible to prevent droplets of rainwater or the like from entering the ventilation opening. Therefore,
Premature deterioration of the timing belt and the like due to adhesion of rainwater and the like and occurrence of tooth skipping are prevented.

According to the second aspect of the invention, the ventilation opening of the front cover according to the first aspect of the invention is provided on the inner peripheral side wall portion on the rear side of the vehicle with respect to the engine mount member. As a result, the traveling wind flowing from the front side of the vehicle to the rear side of the vehicle as the vehicle travels is efficiently introduced into the ventilation opening, while the droplets in the air moving along with the traveling wind flow from the engine mount member. Is also blocked by the front cover on the front side of the vehicle and does not enter the ventilation opening. Therefore, it is possible to sufficiently introduce outside air into the storage space while suppressing intrusion of droplets in the air.

According to the third aspect of the present invention, the first or second aspect is provided.
The accessory according to the invention described in (1) is a fuel injection pump, and an auxiliary pulley on an input shaft of the fuel injection pump is located on the vehicle front side with respect to the engine mount member, while the cam pulley is located on the vehicle rear side with respect to the engine mount member. The upper cover member is provided to cover the fuel injection pump and a fuel supply pipe connected to the fuel injection pump.

Since the belt transmission drives the fuel injection pump that discharges high-pressure fuel, a large load is likely to be applied to the timing belt and the pulley. Therefore, in such a case, the temperature rise of the storage space is suppressed,
It is extremely effective to prevent a reduction in the reliability of the belt transmission mechanism.

Further, since the upper cover member is provided so as to cover the upper part of the fuel injection pump located on the front side of the vehicle, the upper cover member can reduce invasion of rainwater or the like from diagonally above the front side of the vehicle. Moreover, since the upper cover member covers the fuel injection pump and the fuel supply pipe, engine noise leaking outside the vehicle can be reduced.

According to a fourth aspect of the present invention, in the third aspect of the present invention, the camshaft or the pump input is provided to at least one of the camshaft and the cam pulley or the input shaft of the fuel injection pump and the auxiliary pulley on the input shaft. A torsional damper for attenuating the angular velocity fluctuation of the shaft shall be provided.

That is, in general, the torsional damper is tuned in accordance with the natural frequency of the entire belt transmission mechanism so as to effectively prevent the angular velocity fluctuation of the camshaft and the like from becoming excessive due to resonance. is there. Therefore, when the hardness or the like of the timing belt changes due to an increase in the ambient temperature of the housing space and the natural frequency of the belt transmission mechanism changes, a problem occurs that the effect of reducing the angular velocity fluctuation by the torsional damper cannot be obtained sufficiently as intended. . Therefore, in the case where the torsional damper is provided as in the present invention, the above-mentioned disadvantages can be suppressed by introducing the outside air into the housing space and suppressing the rise in the ambient temperature of the belt transmission mechanism.

According to a fifth aspect of the present invention, the upper surface of the front cover according to the second aspect of the present invention is formed so as to gradually decrease from the vehicle rear side toward the vehicle front side, and is located on the vehicle front side with respect to the ventilation opening. It is assumed that a wall portion is vertically provided in a range including at least the upper side of the front cover in the vehicle left-right direction.

As a result, the droplets in the air that move on the traveling wind flowing from the front side of the vehicle to the rear side of the vehicle are blocked by the wall portion that is vertically provided on the vehicle front side with respect to the ventilation opening. Intrusion into the ventilation opening is suppressed.

According to a sixth aspect of the present invention, the front cover according to the second aspect of the present invention is provided so as to extend from the cylinder head of the engine to the cylinder head cover, and the cylinder head cover and the cylinder head cover on the vehicle front side with respect to the ventilation opening. An outside air introduction path for introducing outside air into the ventilation opening between the front cover and the front cover, and a weir having a smaller path cross-sectional area than the other parts in the middle of the outside air introduction path. The upper cover member is provided so as to cover above the outside air introduction path.

As a result, the traveling wind flows from the front side of the vehicle to the rear side of the vehicle through the outside air introduction path between the cylinder head cover and the front cover, and the flow is restricted by a weir portion in the middle.
Once the flow rate increases, the flow rate decreases again after passing through the weir. Then, when the flow velocity decreases, the droplets in the air that have moved on the traveling wind are separated, so that the outside air containing almost no droplets is guided to the ventilation opening.

According to a seventh aspect of the present invention, in the sixth aspect of the present invention, the front side of the vehicle on the upper surface of the cylinder head cover is formed lower than the rear side of the vehicle. Also, it is assumed that an upright bank portion is protruded from the rear side of the vehicle through the front cover side of the oil injection hole to a portion on the vehicle front side of the weir.

As a result, for example, rainwater or oil spilled at the time of oil supply on the upper surface of the cylinder head cover is prevented from falling by the bank and flows from the rear side of the vehicle to the front side of the vehicle. Fall. That is,
The liquid droplets on the upper surface of the cylinder head cover can be prevented from directly dropping to the front cover side on the rear side of the vehicle with respect to the weir portion, thereby preventing rainwater, oil, and the like from entering the ventilation opening from above. .

According to an eighth aspect of the present invention, the front cover according to the first aspect of the present invention has a main wall portion that is superposed on the front surface of the engine and has an inner peripheral side wall formed integrally therewith.
The inner peripheral side wall portion is provided with a droplet guide portion for guiding the liquid droplets adhering to the surface facing the storage space to the main wall portion.

That is, generally, in the housing space after the engine is stopped, the water vapor in the air is liquefied and dewed due to the temperature drop, and the water droplets fall from the inner peripheral side wall and directly adhere to the timing belt or the pulley. There is. Therefore, in the present invention, on the surface of the inner peripheral side wall portion facing the accommodation space, a droplet guide portion for guiding the liquid droplets adhering to the surface to the main wall portion is provided, and the water droplet generated by the condensation as described above is provided. The water droplets can be prevented from adhering to the timing belt and the like by being guided from the inner peripheral side wall portion to the main wall portion and flowing downward along the main wall portion.

According to a ninth aspect of the present invention, the droplet guide portion according to the eighth aspect of the present invention is provided substantially directly above the crank pulley and at a lower end portion of the inner peripheral side wall portion. It is assumed that flanges are provided at both ends in the direction.

That is, generally, in a horizontally mounted engine, an engine mount member is disposed on the front end face of the engine above the crankshaft in order to reduce idle vibration due to the inertia main shaft mount. The lower end of the peripheral side wall is often located almost directly above the crank pulley. Also, droplets attached to the surface of the inner peripheral side wall facing the storage space collect at the lower end of the inner peripheral side wall. It is conceivable that the water drops directly on the crank pulley and accumulates between the teeth and the flange of the crank pulley.
As a result, especially in a cold region, the liquid that has accumulated before the engine is restarted freezes, which may cause tooth jump between the crank pulley and the timing belt.
Therefore, particularly in such a case, it is extremely effective that the droplet guide can prevent the droplet from dropping onto the crank pulley.

[0027]

Embodiments of the present invention will be described below with reference to the drawings.

(Overall Configuration of Engine) FIGS.
1 shows an appearance of a diesel engine E according to an embodiment of the present invention. As shown in FIG. 6, the engine E has a cylinder head 2 mounted on an upper surface of a cylinder block 1 and is integrated therewith. Inside the engine E, a front-rear direction of a crankshaft 3 supported by the cylinder block 1 extends ( This is an in-line four-cylinder engine in which four cylinders (cylinders) (not shown) are formed along the vertical direction in FIG. The engine E is mounted horizontally so that the crankshaft 3 extends in the left-right direction of the vehicle (not shown).

In this specification, for convenience of explanation, the longitudinal direction of the cylinder block 1, that is, the crankshaft 3
3 is referred to as the front side of the engine E, the lower side in FIG. 3 is referred to as the front side of the engine E, and the opposite side (the upper side in FIG. 3) is referred to as the rear side of the engine E. The engine E
In the left-right direction (left-right direction in FIGS. 2 and 3) orthogonal to the front-rear direction, the right side (left side in FIGS. 2 and 3) facing the front side of the engine E is called the right side of the engine E, and the opposite side (FIG. 2 and the right side of FIG. 3) will be referred to as the left side of the engine E.

At the front end of the engine E, a crankshaft 3
A belt transmission mechanism A described later that drives the camshaft 4 (see FIG. 4), the fuel injection pump 5 (see FIG. 7), and the like in synchronization with the rotation of
(See FIG. 1), and the belt transmission mechanism A
As shown in FIG. 2, a resin-made sealing plate 6 made of a steel plate and superposed on the front end face of the cylinder block 1, and an upper cover 7 and a lower cover 8 fastened to the sealing plate 6. It is housed in a housing space in a front cover C having a belt cover. Also,
A V-pulley 9 is attached to a front end of the crankshaft 3. The V-pulley 9, a V-pulley 10 a provided on an input shaft of an alternator 10, and a V-pulley 11 provided on an input shaft of a compressor for an air conditioner (not shown). Are drivingly connected by two V-belts 12. Further, on the front end surface of the cylinder block 1, a connecting member 13 connected to an engine mount (not shown) is provided with four bolts 14, 14,.
... attached. The engine mount member 13 is disposed substantially directly above the crankshaft 3 on the front end surface of the engine in order to reduce idle vibration caused by the inertia main shaft mount.

Further, on the upper surface of the cylinder head 2,
As shown in FIG. 3, a cylinder head cover 18 is provided, and a resin sound insulation cover (upper part) that covers a part of the cylinder head cover 18 and the fuel injection pump 5 and a fuel supply pipe 19 from the fuel injection pump 5. Cover member)
20 are provided. As shown in FIG. 2, the sound insulation cover 20 is gradually lowered from the vehicle rear side to the vehicle front side along the hood line B of the vehicle above the front cover C.

In FIG. 2, reference numeral 22 denotes an oil pan attached to the lower surface of the cylinder block 1, reference numeral 23 denotes a turbocharger, reference numeral 24 denotes an oil filter, and reference numeral 25 denotes one end (the left end in the drawing) of the cylinder head 2. , While the other end is connected to a radiator (not shown). In FIG. 3, reference numeral 26 denotes a vacuum pump driven by the camshaft 4.

(Structure of Cylinder Head) The engine E
Is a so-called SOHC (Single Over Head Cam) type engine. Although not shown, four cylinders are arranged at predetermined intervals in the front-rear direction at a position deviated leftward from the left-right center of the cylinder head 2. I have. on the other hand,
As shown in FIGS. 4 and 5, at a position deviated to the right side (left side in both figures) of the cylinder head 2, that is, at a position rearward of the cylinder with respect to the center line of the cylinder when the engine E is mounted on the vehicle, Six bearing portions 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, and 28 are arranged so that the camshaft 4 extends in the front-rear direction and the axis position is substantially the same as the upper surface of the cylinder head. Are rotatably supported by.

The cylinder head 2 is fastened to the cylinder block 1 by head bolts 29, 29,... Arranged so as to surround each cylinder at four locations at equal intervals in the circumferential direction. Are arranged so that the injection holes face the combustion chamber directly and extend along the cylinder center line. Also, the injection nozzles 30, 30,.
, Two intake valves 31, 31 and two exhaust valves 32, 32 are provided for each cylinder. The intake and exhaust valves 31, 32,... Are respectively provided with intake cams 4a, 4a,.
Are opened and closed via the rocker arms 33, 33,.

More specifically, as shown in FIG. 5 only, each of the exhaust rocker arms 33 is swingably supported by a rocker shaft 34 which is supported obliquely above and parallel to the camshaft 4 and has one end. Cam roller 3 provided in the section
3a, while being in sliding contact with the exhaust cam 4b of the camshaft 4, substantially through a pressing bolt 33b provided at the other end.
It is in contact with the U-shaped pressing member 35. On the other hand, a cam pulley 36 is attached to the front end of the camshaft 4 as shown in FIG. 1, and the cam pulley 36, the crank pulley 37 attached to the front end of the crankshaft 3, and the fuel injection pump 5 Pump pulley 3 attached to input shaft 5a
8 are driven and connected by a timing belt 39 having a tooth portion on the inner peripheral side, thereby forming a belt transmission mechanism A.

When the camshaft 4 is rotated in synchronization with the rotation of the crankshaft 3, the exhaust cams 4b, 4b,.
Are rocked at a predetermined timing for each cylinder by the
Pushes down the pressing member 35, whereby the two exhaust valves 32, 32 are opened and closed in synchronization with the rotation of the crankshaft 3. Although not shown in detail, the intake valves 31, 3
Are opened and closed in the same manner as the exhaust valves 32, 32,. Since a single camshaft 4 is used to open and close a number of valves via the rocker arms 33, 33,..., In this engine E, the valve reaction force to the camshaft 4 becomes large. Accordingly, the driving load applied to the timing belt 39 for driving the camshaft 4 becomes extremely large.

(Mounting Structure of Fuel Injection Pump) As shown in FIGS. 6 and 7, the fuel injection pump 5 is located on the left side of the engine E, that is, on the vehicle front side of the cylinder center line in the vehicle mounted state, from the engine left and right direction. When viewed, at least a portion is arranged so as to overlap with the cylinder head 2, and is fixed to the engine side by a bracket 41 attached across the cylinder block 1 and the cylinder head 2.

That is, the bracket 41 has four bolts 43, 4 extending rearward along the left side surfaces of the cylinder block 1 and the cylinder head 2.
Fastened to the left side of the cylinder block 1 by 3, ...
The connecting portion 4 is fastened to the left side surface of the cylinder head 2 by one bolt 44 and extends from the front end of the flange portion 42 along the front end surface of the cylinder block 1.
2a is fastened to the front end face of the cylinder block 1 by bolts 14 together with the connecting member 13 of the engine mount. Further, the bracket 41 has a flange 42
Are integrally formed with a mounting flange portion 46 extending from the front end portion to the opposite side in the same plane as the front end surface of the cylinder block 1.

In the fuel injection pump 5, the input shaft 5a passes through the hole 46a of the mounting flange 46, and the position of the axis of the input shaft 5a is exactly the mating surface of the cylinder block 1 and the cylinder head 2. Is mounted to the mounting flange portion 46 with a bolt so that the height of the mounting flange portion is equal to the height. Although not shown, the fuel injection pump 5 is a distribution type pump that individually supplies fuel to the injection nozzle 30 of each cylinder by operating one plunger.
A cam for reciprocating the plunger by each of the two cam lobes, and a distributor for distributing the fuel from the plunger and individually supplying the fuel to the injection nozzles 30, 30,... By the fuel supply pipes 19, 19,. ing. Then, the input shaft 5a is rotated in synchronization with the rotation of the crankshaft 3;
During the rotation, the plunger is operated four times in total at a predetermined fuel injection timing for each cylinder, the injection nozzles 30, 30,... Are opened by the pressure of the supplied fuel, and high-pressure fuel is directly supplied to each combustion chamber. It is injected. Since the discharge pressure of the fuel injection pump 5 is set extremely high, for example, 70 MPa or more, the driving load of the input shaft 5a for operating the plunger becomes extremely large.

(Structure of Belt Transmission Mechanism) In the belt transmission mechanism A, as shown in FIG.
6. In addition to the crank pulley 37 and the pump pulley 38, the automatic tensioner 5 is wound around a water pump pulley 53 for driving a water pump (not shown).
The first tensioner pulley 54 and the idler pulley 55 have a layout directed toward the inner peripheral side of the belt.
When the crankshaft 3 rotates clockwise in the figure, the cam pulley 36, the crank pulley 37,
The pump pulley 38 and the water pump pulley 53 are rotated clockwise, and at the same time, the tensioner pulley 54 and the idler pulley 55 are rotated counterclockwise.

The cam pulley 36 is provided on the timing belt 3 having a loose side span (left side in FIG. 1) having a relatively small tension.
The water pump pulley 53 and the tensioner pulley 54 are arranged in the middle of the loose side span. The cam pulley 36 is
The pitch circle has a diameter twice as long as the crank pulley 37, and as shown in FIGS. 8 and 9, a cylindrical boss portion 36a protruding on the inner peripheral side in the direction in which the axis x1 of the rotation shaft extends is provided. On the other hand, on the outer peripheral side, teeth that mesh with the teeth of the timing belt 39 are formed over the entire circumference.

Further, on the outer peripheral side of the cam pulley 36, flanges 36b, 36 are provided at both ends in the direction of the axis x1.
b is provided to restrict the movement of the timing belt 39 in the belt width direction. That is, generally, there is a displacement in the engine front-rear direction due to an assembly error between the cylinder head 2 and the cylinder block 1, so that a displacement also occurs between the cam pulley 36 and the crank pulley 37. Therefore, in this embodiment, the cam pulley 3
6, flanges 36b, 36b are provided, and a similar flange is also provided on the crank pulley 37. The flanges restrict the movement of the timing belt 39 in the belt width direction at two places vertically separated from each other. doing. As a result, each pulley 36,
The deviation from 37 and 38 can be effectively suppressed.

The boss 36a of the cam pulley 36
, The annular torsion damper 50 is press-fitted from the tip side in an externally fitted state, and the cam pulley 36 and the torsion damper 50 rotate integrally to attenuate the angular velocity fluctuation of the camshaft 4. The torsion damper 50 is obtained by integrally vulcanizing and bonding an outer peripheral side mass member 50a, an inner peripheral side sleeve 50b, and a vibration damping rubber 50c therebetween.
By setting the weight of “a” and the vibration absorption characteristics of the vibration damping rubber 50c, required damping characteristics corresponding to the natural frequency of the belt transmission mechanism A can be obtained. For example, the weight of the torsion damper 50 may be substantially the same as the weight of the cam pulley 36 as a single body.

In the cam pulley 36, two through holes 36c, 36c penetrating in the direction of the axis x1 are formed at symmetrical positions in the diameter direction, while the torsion damper 5 is formed.
0, the cam pulley 36 is provided with through holes 50d, 50d,... At positions corresponding to the through holes 36c. When the worker attaches the cam pulley 36 to the cam shaft 4, the through holes 50d, 36c The alignment mark (not shown) written on the side of the cylinder head 2 can be confirmed.

On the other hand, the pump pulley 38 is arranged so that the timing belt 39 on the tight side span (right side in FIG. 1) advances, and the diameter of the pitch circle is twice as large as that of the crank pulley 37, like the cam pulley 36. Although the length is set, the diameter is smaller than the cam pulley 36 as a whole because the flange is not provided. In addition, in the present embodiment, the weight of the pump pulley 38 is substantially the same as the weight of the cam pulley 36 having substantially the same diameter. , The angular velocity fluctuation of the pump pulley 38 is reduced.

As shown in FIGS. 10 and 11, the auto tensioner 51 includes a tensioner pulley 5 which is engaged with the loose side span of the timing belt 39 from the outer peripheral side of the belt.
4 and a rotation arm 56 that cantileverably supports the tensioner pulley 54 from the front side of the engine (one side in the axial direction of the rotation shaft) and rotates around the rotation shaft 51a. A hydraulic cylinder 57 fastened and fixed to the cylinder block 1 urges the turning arm 56 to turn toward the timing belt 39.

That is, the hydraulic cylinder 57 is connected to the rotating arm 56 by a piston rod 57b provided on the cylinder body 57a so as to be able to advance and retreat, and a coil spring (not shown) disposed inside the cylinder body 57a is provided. Thereby, the piston rod 57b is moved to the extension side. The hydraulic cylinder 57 causes the tensioner pulley 54 to move the timing belt 3
9. Following the movement of No. 9, the timing belt 39 is pressed,
Adjust the tension constantly. The hydraulic cylinder 57
Is provided with a hydraulic damper structure for restricting the movement of the piston rod 57b to the contraction side by the flow resistance of the pressure oil in the cylinder body 57a, and the timing belt 39 transmitted through the rotating arm 56 and the tensioner pulley 54. To attenuate the reaction force.

Further, since the auto tensioner 51 has a structure in which the tensioner pulley 54 is cantilevered from the front side of the engine (upper side in FIG. 11) by the rotating arm 56, it is compact as a whole as compared with a structure in which it is supported at both ends. It has become. The timing arm 39 may be displaced in the belt width direction due to the rotation of the rotation arm 56 due to the belt reaction force acting on the tensioner pulley 54 and the displacement of the tensioner pulley 54 in the direction in which the rotation shaft 51a extends. It is conceivable that the cam pulley 36 is provided with the flanges 36b, 36b as described above, so that a running defect or the like due to the displacement of the timing belt 39 does not occur.

(Configuration of Front Cover) In this embodiment, a ventilation opening is formed in the front cover C in order to suppress a rise in the temperature of the housing space in which the belt transmission mechanism A is housed. Hereinafter, the configuration of the front cover C will be described in detail with reference to FIG. 1 and FIGS.

As shown in FIG. 1, the front cover C
Mainly, a seal plate 6 disposed from the cylinder block 1 to the cylinder head 2, the cylinder head cover 18 and the bracket 41 of the fuel injection pump 5 (see FIG. 6), and a cylinder block lower than the seal plate 6. 1, a cylinder block cover 62 having a through-hole formed in the center thereof and through which the crankshaft 3 passes, an upper cover 7 fastened to the seal plate 6 (see FIGS. 2 and 3), and the seal plate 6 And the lower cover 8 fastened to the cylinder block cover 62.

The seal plate 6 is formed by press-forming a thin steel plate as shown in each of FIGS. 12 to 14, and includes a main wall portion 63 superposed on the front end surface of the cylinder block 1 and the like, An outer peripheral side wall portion 6 extending in the engine front-rear direction from the main wall portion 63 so as to surround the outer periphery of the belt 39.
4 and an annular inner peripheral side wall portion 65 extending substantially in the front-rear direction of the engine around the engine mount connecting member 13 at a substantially central portion of the main wall portion 63.

Further, the seal plate 6 is fastened to the front cover portion 18a of the cylinder head cover 18 at a first fastening portion 6a which is fastened directly to the cylinder block 1 and at an outer peripheral side wall portion 64 located near the cam pulley 36. The second fastening portion 6b, the third fastening portion 6c and the fourth fastening portion 6 fastened to the bracket 41 of the fuel injection pump 5.
d is provided. That is, the seal plate 6
Are directly attached to the cylinder block 1 by the bolts 66 at the first fastening portions 6a, thereby minimizing the clearance between the seal plate 6 and the cylinder block 1, and The positional accuracy with respect to the cylinder block 1 can be made extremely high.

On the other hand, in the second, third and fourth fastening portions, the seal plate 6 is attached via a rubber mount 67 by bolts 66 as shown in FIG. That is, since the seal plate 6 is attached via the rubber mount 67 to the cylinder head cover 18 and the bracket 41, which have a misalignment due to an assembling error with the cylinder block 1, the above-described rubber mount 67 allows the seal plate 6 to be mounted. The displacement caused by the assembly error is absorbed, and the distortion of the seal plate 6 in the assembled state is reduced. This allows the cam pulley 3
6 and the clearance between the pump pulley 38 and the seal plate 6 can be made extremely small, thereby reducing the size of the engine in the front-rear direction.

The main wall 63 of the seal plate 6 has
The pump pulley 38 is provided at a position corresponding to the pump pulley 38.
A substantially circular hole 63 a having a slightly smaller diameter is formed, and a substantially central position of the hole 63 a is positioned at the input shaft 5 of the fuel injection pump 5.
a penetrates. Similarly, the water pump pulley 53
A circular hole 63b having a diameter larger than that of the water pump pulley 53 is formed at a position corresponding to the water pump pulley 53, and an input shaft of the water pump penetrates a substantially central position of the hole 63b. A portion of the main wall 63 corresponding to the cam pulley 36 is cut out so as to open upward. As shown in FIGS. 16 and 17, the front cover 18a of the cylinder head cover 18 is And constitutes a part of the front cover C.

The outer peripheral side wall 64 of the seal plate 6
Are connected to the pump pulley 3 with the notch 63c of the main wall 63 as a boundary.
8 and a cam pulley 36 side. The height of the outer peripheral side wall portion 64 protruding from the main wall portion 63 varies depending on the location. That is, as shown in FIG. 13, in a portion extending from almost directly above the pump pulley 38 to the lower end portion of the seal plate 6 around the outer periphery, the outer peripheral side wall portion 64 has a front end portion substantially at the same position as the front end surface of the pump pulley 38. It extends and is formed high so as to cover the pump pulley 38 in the engine front-rear direction. On the other hand, FIG.
3, as shown in FIG. 14 and FIG.
4, a predetermined portion from the periphery of the cam pulley 36 to the pump side is formed by the cam pulley 36 and the timing belt 39.
Is formed low in the front-rear direction so that almost is exposed,
Further, corresponding to this portion, the side wall portion 7a on the upper cover 7 side is formed deep in the front-rear direction, as indicated by the phantom line in FIG. As a result, the upper cover 7
The timing belt 39 is exposed from the periphery of the cam pulley 36 to the pump side by simply removing the cam pulley 36, and can be easily inspected.

As shown in FIGS. 1 and 12, the inner peripheral side wall portion 65 is formed so as to be curved along each of the pulleys 36 and 38 in the vicinity of the cam pulley 36 and the pump pulley 38, respectively. As shown in FIG. 17, a ventilation opening 6 for introducing outside air into the accommodation space is provided in a portion extending in the vertical direction near the cam pulley 36.
9 are provided. Also, as shown in FIG.
A predetermined distance is provided between the cylinder head cover 18 and the seal plate 6 on the vehicle front side (the right side in the figure) with respect to the ventilation opening 69, and the vehicle travels from the vehicle front side (the right side in the figure). A path (outside air introduction path) W for introducing wind into the ventilation opening 69 is provided. That is, the traveling wind flowing from the vehicle front side to the vehicle rear side as the vehicle travels is ventilated through the outside air introduction path W between the seal plate 6 and the cylinder head cover 18 as indicated by the arrows in FIGS. Opening 69, and the ventilation opening 6
9 is introduced into the accommodation space. On the other hand, the air in the storage space is discharged to the outside through a hole 63d formed in the main wall 63 below the cam pulley 36.

The ventilation opening 69 is formed from the inner peripheral side wall 65 to the main wall 63 as shown in FIG. 18, and is close to the cam pulley 36 and includes its flange 36b. Is located as follows. That is, a seat surface 2a (shown only in FIG. 16) to which one end of the water outlet hose 25 (see FIG. 1) is connected is formed in the cylinder head 2 near the ventilation opening 69. The distance between the seat 2 and the cam pulley 36 is extremely small. Therefore, when the ventilation opening 69 is not provided, there is a concern that the inner peripheral side wall portion 65 may come into contact with any of the cam pulley 36 and the water outlet hose 25 to generate noise or vibration. Is done. On the other hand, since the opening is formed in the inner peripheral side wall portion 65 between the cam pulley 36 and the water outlet hose 25 which are extremely narrow as described above, the generation of the vibration noise is reliably avoided.

Further, bolts 70 for fastening the cylinder head cover 18 to the cylinder head 2 are connected to the ventilation openings 6.
As shown in FIG. 19, the portion corresponding to the ventilation opening 69 of the cylinder head cover 18 and the cylinder head 2 protrudes toward the seal plate 6 as shown in FIG. Is formed as the boss 71. On the other hand, the cylinder head cover 18 immediately above the ventilation opening 69 is shaved,
The bolt 70 is exposed. That is, the seal plate 6
The boss portion 71 protruding to the side is housed in the ventilation opening 69, while the boss portion 71 directly above the boss portion 71 is cut off, and the seal plate 6 is arranged as close as possible to the cylinder head cover 18. Thus, the dimension in the front-rear direction of the engine is reduced.

The lower end of the inner peripheral side wall 65 is located almost directly above the crank pulley 38, and as shown in FIG.
A droplet guide portion 65a for guiding the droplet to the liquid is provided. That is, in the housing space in the front cover C, water vapor in the air is condensed due to a decrease in temperature after the engine is stopped, and water droplets adhere to the surface of the inner peripheral side wall portion 65. Then, the water droplets flow from the lower end portion of the inner peripheral side wall portion 65 to the droplet guide portion 6.
5a to the main wall 63, and then the main wall 6
3 flows downward, and is discharged to the outside from the joint portion with the cylinder block cover 62, so that it does not adhere to the timing belt 39, the crank pulley 37, or the like.

Above the ventilation opening 69 and the engine mount connecting member 13, the front cover C is covered by the sound insulating cover 20 from above. The sound insulation cover 20 is formed by injection molding of a resin as shown in FIGS. 21 and 22, and a portion on the vehicle rear side (the left side portion in FIG. 22) that covers the upper surface of the cylinder head cover 18 is formed by injection. Circular protrusions 20a, 20a,... Protruding upward corresponding to the positions of the nozzles 30, 30,. On the other hand, in the front part of the vehicle, almost half of the front side of the engine (lower side in the figure) extends to the front side of the vehicle, and the fuel injection pump 5 and the fuel supply pipe 19 are covered below that part. The engine noise leaking to the engine is reduced.

The sound insulation cover 20 is located above the ventilation opening 69 and the engine mount connecting member 13.
That is, it covers the front side of the vehicle above the ventilation opening 69 so that rainwater or the like dripping from the hood hood B (see FIG. 2) does not enter the ventilation opening 69. Further, the sound insulating cover 20 covers the upper portion of the seal plate 6 at a portion where the height of the outer peripheral side wall portion 64 is changed, which is a portion where the height of the outer peripheral side wall portion 64 is changed. In this case, since the sealing property between the seal plate 6 and the upper cover 7 is slightly reduced, the drop in the sealing property is compensated for and the intrusion of the droplets into the storage space is reliably prevented.

A vertically extending wall 20b is integrally formed on the outer peripheral edge of the sound insulation cover 20. Further, at a predetermined position on the front side of the vehicle with respect to the ventilation opening 69, the left and right direction of the vehicle is reduced. A wall 20c extending vertically in a range including the front cover C is provided so as to be connected to the wall 20b. The wall portion 20c blocks the droplets in the air moving on the traveling wind flowing from the front side of the vehicle to the rear side of the vehicle and suppresses the intrusion of the droplets from the front side of the vehicle into the ventilation opening 69. It is.

As shown in FIGS. 16 and 17, the outside air introduction path W between the cylinder head cover 18 and the seal plate 6 below the sound insulation cover 20 projects from the cylinder head cover 18 toward the seal plate 6 and travels. A plate-shaped weir 72 is provided to reduce the cross-sectional area of the wind path as compared with other portions. That is, the traveling wind flowing to the rear side of the vehicle through the outside air introduction path W as the vehicle travels is narrowed by the weir portion 72, and the flow velocity once rises.
After 2 the flow rate drops again. At this time, water droplets, oil droplets, sand, and the like in the air that have moved along with the traveling wind are separated, and outside air containing almost no droplets is introduced into the ventilation opening 69.

The upper surface of the cylinder head cover 18
It is formed so as to gradually decrease from the periphery of the oil injection hole 74 on the rear side of the vehicle to the front side of the vehicle. An upstanding bank portion 75 is formed to surround the front side of the engine and extend from the weir portion 72 to the front side of the vehicle. The bank 75 prevents, for example, rainwater accumulated on the upper surface of the cylinder head cover 18 and oil spilled at the time of replenishment from dropping from the front edge of the engine, and droplets of rainwater and the like pass over the cylinder head cover 18 from the vehicle rear side to the vehicle front side. , And always falls downward on the front side of the vehicle with respect to the weir portion 72.

(Effects of Embodiment) Therefore, according to the engine cover structure of this embodiment, the engine mount connecting member 13 of the inner peripheral side wall portion 65 of the seal plate 6 surrounding the engine mount connecting member 13. A ventilation opening 6 is provided at a portion extending in the vertical direction on the rear side of the vehicle.
Because of the provision of 9, the outside air can be efficiently introduced into the accommodation space from the ventilation opening 69 by the traveling wind flowing from the vehicle front side to the vehicle rear side as the vehicle travels. As a result, the timing belt 39 and the pulleys 36, 37 in the accommodation space can be increased without increasing the outer dimensions of the front cover C.
The temperature rise of the bearings 38, 53 and the water pump (not shown) can be suppressed, and the reliability of the belt transmission mechanism A can be prevented from lowering.

The ventilation opening 69 is provided at a portion of the inner peripheral side wall 65 extending in the up-down direction.
Further, since the sound insulation cover 20 is provided so as to cover the upper part thereof, for example, rainwater or the like dripping from the hood hood B of the vehicle is prevented from entering the ventilation opening 69. Moreover, the walls 20b, 20c provided on the sound insulating cover 20 are provided.
And the weir 72 provided on the cylinder head cover 18 allows droplets in the air to flow from the front side of the vehicle to the ventilation opening 69.
In addition to the above, it is possible to prevent rainwater, oil, and the like accumulated on the upper surface of the cylinder head cover 18 from entering the ventilation opening 69 from above by the bank portion 75 provided on the upper surface of the cylinder head cover 18. Can be blocked. That is, even when the ventilation opening 69 is provided in the front cover C and outside air is introduced, the intrusion of the droplet into the ventilation opening 69 is suppressed, and the timing belt 39 caused by the adhesion of the droplet is prevented. Premature deterioration of the pulleys 36, 37, 38, 53 can be prevented.

In particular, in the diesel engine E according to this embodiment, since the driving load of the valve train camshaft 4 is relatively large and the driving load of the fuel injection pump 5 is also large, the timing belt 39, the pulleys 36, 37, 38, 53 and the bearings of the water pump tend to be overloaded. Therefore, suppressing the temperature rise of the storage space while preventing the droplets from adhering to the timing belt 39 and the like can be achieved by:
This is extremely effective in maintaining the reliability of the belt transmission mechanism A.

Further, since the torsional damper 50 tuned in accordance with the resonance frequency specific to the belt transmission mechanism A is used in the belt transmission mechanism A, the hardness of the timing belt 39 is changed by the temperature change of the housing space. When the torsional damper 5 changes due to a change in the resonance frequency.
There is a problem that the function of “0” is reduced. Then
This inconvenience can be suppressed by suppressing the temperature rise by introducing outside air into the housing space, and the present invention is also effective in this respect.

Further, according to this embodiment, the droplet guide portion 6 provided on the inner peripheral side wall portion 65 of the seal plate 6 is provided with small droplets such as rainwater or water droplets due to condensation that have entered the storage space.
5a flows downward along the main wall portion 63 of the seal plate 6, and the timing belt 39 and the pulleys 36, 3
Since the toner can be discharged to the outside without adhering to the belts 7, 38, it is possible to more reliably prevent the reliability of the belt transmission mechanism A from deteriorating due to the adhesion of liquid droplets.

In particular, since the lower end of the inner peripheral side wall portion 65 is located almost directly above the crank pulley 37, if the droplet guide portion 65a is not provided, water drops directly fall on the lower crank pulley 37. Therefore, it accumulates between the tooth portion and the flange portion of the crank pulley, and freezes by the time the engine is restarted in, for example, a cold region, causing the tooth jump between the crank pulley 37 and the timing belt 39 to occur. It may be the cause. However, in this embodiment, since the droplet guide portion 65a is provided as described above, the above-described problem can be reliably prevented.

In this embodiment, the present invention is applied to the direct injection diesel engine E. However, the present invention is not limited to this, and may be applied to, for example, a sub-chamber diesel engine or a gasoline engine.

[0072]

As described above, according to the cover structure of the horizontally mounted engine according to the first aspect of the present invention,
A ventilating opening is provided in a vertically extending portion of an inner peripheral side wall on the engine mount member side of a front cover that accommodates the belt transmission mechanism, and an upper cover member that covers above the ventilating opening is provided. Thus, it is possible to introduce outside air into the housing space while preventing rainwater or the like from entering the ventilation opening. Therefore, it is possible to suppress an increase in the temperature of the housing space without increasing the outer dimensions of the front cover, and to maintain the reliability of the belt transmission mechanism.

According to the second aspect of the invention, the traveling wind accompanying the traveling of the vehicle can be efficiently introduced into the ventilation opening while suppressing the intrusion of droplets in the air.

According to the third aspect of the present invention, the effect of suppressing the rise in the temperature of the accommodation space becomes extremely effective when a large load is applied to the timing belt and the pulley.
In addition, the upper cover member can reduce intrusion of rainwater and the like from diagonally above the front side of the vehicle, and reduce engine noise leaking outside the vehicle.

According to the fourth aspect of the present invention, by suppressing the rise in the temperature of the housing space due to the introduction of outside air, it is possible to prevent the function of the torsional damper from decreasing due to the temperature change.

According to the fifth aspect of the present invention, the wall provided on the upper cover member can prevent the liquid droplets from entering the ventilation opening from the front side of the vehicle.

According to the sixth aspect of the invention, intrusion of droplets from the front side of the vehicle to the ventilation opening through the outside air introduction path can be suppressed by the weir provided in the path.

According to the invention, rainwater or oil on the upper surface of the cylinder head can be prevented from entering the ventilation opening from above by the bank provided on the upper surface of the cylinder head cover.

According to the eighth aspect of the present invention, the liquid droplets adhering to the surface of the inner peripheral side wall portion facing the accommodation space can be discharged to the outside without adhering to the timing belt or the pulley by the liquid droplet guide portion.

According to the ninth aspect of the present invention, when the crank pulley is located substantially directly below the lower end of the inner peripheral side wall, the effect of the droplet guide portion becomes extremely effective.

[Brief description of the drawings]

FIG. 1 is a front view showing a cover structure of a horizontally mounted engine according to an embodiment of the present invention.

FIG. 2 is a front view of an engine to which the cover structure of FIG. 1 is applied.

FIG. 3 is a plan view of FIG. 2;

FIG. 4 is a front view showing a configuration of a cylinder head in a state where a rocker shaft and the like are omitted.

FIG. 5 is an explanatory view showing a configuration in which a rocker arm opens and closes an exhaust valve.

FIG. 6 is a front view showing a configuration in which a bracket of the fuel injection pump is mounted on an engine side.

FIG. 7 is a left side view of FIG.

FIG. 8 is a front view showing a configuration of a cam pulley and a torsion damper.

9 is a sectional view taken along line IX-IX in FIG.

FIG. 10 is a front view showing a configuration of the auto tensioner.

11 is a sectional view taken along line XI-XI in FIG.

FIG. 12 is a front view showing a configuration of a seal plate.

FIG. 13 is a plan view of FIG.

FIG. 14 is a right side view of FIG.

FIG. 15 is a cross-sectional view illustrating a configuration of a rubber mount.

FIG. 16 is a front view showing an arrangement configuration of a cylinder head cover and a seal plate, and a state in which traveling wind is introduced into a ventilation opening of the seal plate.

FIG. 17 is a plan view of FIG. 16;

FIG. 18 shows the configuration of the ventilation opening, and is shown in FIG.
It is sectional drawing in the XVIII line.

FIG. 19 shows a positional relationship between a ventilation opening and a boss.
FIG. 17 is a sectional view taken along line XIX-XIX in FIG. 16.

FIG. 20 shows a configuration of a droplet guide section, and is XX-XX in FIG. 12;
It is sectional drawing in a line.

FIG. 21 is a front view showing a configuration of a sound insulation cover.

FIG. 22 is a plan view of FIG. 21.

[Explanation of symbols]

Reference Signs List A belt transmission mechanism C front cover E diesel engine W outside air introduction path 1 cylinder block 2 cylinder head 3 crankshaft 4 valve train camshaft 5 fuel injection pump 5a fuel injection pump input shaft 6 seal plate (front cover) 7 upper cover (Front cover) 8 Lower cover (Front cover) 13 Engine mount connecting member 18 Cylinder head cover 19 Fuel supply pipe 20 Sound insulation cover (upper cover member) 20c Sound insulation cover wall 36 Cam pulley 37 Crank pulley (38 Pump pulley (Auxiliary machine pulley) 39 Timing Belt 50 Torsion damper 62 Cylinder block cover (front cover) 63 Main wall 65 Inner peripheral wall 65a Droplet guide 69 Ventilation opening 72 Weir 75 Bank

Claims (9)

[Claims] An engine mount member for supporting an engine is provided at one end in the crankshaft direction of an engine mounted horizontally so that a crankshaft extends in the left-right direction of the vehicle, and an engine mount member surrounding the engine mount member. A front cover having a substantially annular housing space disposed therein is provided, and the housing space includes a crank pulley including a timing pulley on a crankshaft, a cam pulley including a timing pulley on a valve train camshaft, In a cover structure of a horizontally mounted engine in which an auxiliary pulley composed of a timing pulley on an input shaft of the auxiliary machine and a timing belt for drivingly connecting these pulleys are accommodated, an engine mount member side of the front cover is used. On an inner peripheral side, an inner peripheral side wall portion extending substantially parallel to the crankshaft direction of the engine is formed. A portion of the peripheral side wall that is close to one of the cam pulley and the accessory pulley and that extends in the vertical direction is provided with a ventilation opening for introducing outside air into the housing space, and at least the ventilation A cover structure for a horizontally mounted engine, wherein an upper cover member is provided to cover the opening from above the front cover. 2. The horizontally mounted engine cover structure according to claim 1, wherein the ventilation opening of the front cover is provided on an inner peripheral side wall portion on a rear side of the vehicle with respect to the engine mount member. 3. The fuel injection pump according to claim 1, wherein the auxiliary device is a fuel injection pump, and an auxiliary pulley on an input shaft of the fuel injection pump is located on a front side of the vehicle with respect to an engine mount member. A horizontal member, which is located on the rear side of the vehicle with respect to the mount member, wherein the upper cover member is provided so as to cover above the fuel injection pump and a fuel supply pipe connected to the fuel injection pump. Cover structure for stationary engine. 4. The torsion according to claim 3, wherein at least one of the camshaft and the cam pulley or the input shaft of the fuel injection pump and an auxiliary pulley on the input shaft is configured to attenuate the angular velocity fluctuation of the camshaft or the pump input shaft. A cover structure for a horizontally mounted engine, which is provided with a damper. 5. The front cover according to claim 2, wherein an upper surface of the front cover is formed so as to gradually decrease from a rear side of the vehicle toward a front side of the vehicle. A cover structure for a horizontally mounted engine, wherein a wall portion is vertically provided in a range including at least the upper part of the cover in the vehicle left-right direction. 6. The front cover according to claim 2, wherein the front cover is provided so as to extend from the cylinder head of the engine to the cylinder head cover, and is provided between the cylinder head cover on the vehicle front side of the ventilation opening and the front cover on the engine front side of the cylinder head cover. An outside air introduction path for introducing outside air to the ventilation opening is provided between the two, and a weir portion having a smaller path cross-sectional area than other portions is provided in the middle of the outside air introduction path. A cover structure for a horizontally mounted engine, wherein the member is provided so as to cover an upper part of the outside air introduction path. 7. The oil injection hole according to claim 6, wherein a front side of the vehicle on an upper surface of the cylinder head cover is formed lower than a rear side of the vehicle, and the upper surface of the cylinder head cover is provided with the oil injection hole from a vehicle rear side of an oil injection hole for an engine. A vertically mounted bank portion extending from the front cover side to the vehicle front side of the weir portion is provided so as to protrude therefrom. 8. The front cover according to claim 1, wherein the front cover has a main wall portion superposed on the front surface of the engine and having an inner peripheral side wall formed integrally therewith. A cover structure for a horizontally mounted engine, comprising a droplet guide portion for guiding droplets adhering to a facing surface to the main wall portion. 9. The droplet guide portion according to claim 8, wherein the droplet guide portion is provided substantially directly above the crank pulley and at a lower end portion of the inner peripheral side wall portion. A cover structure for a horizontally mounted engine, which is provided.