JP4544088B2 - Engine front structure - Google Patents

Description

  The present invention relates to a front structure of an engine in which a plurality of auxiliary machines are disposed on an intake side surface of an engine body and driven by a crankshaft via an auxiliary machine driving belt.

  Conventionally, the power of the crankshaft is transmitted to the camshaft via the drive chain to control the opening / closing timing of the intake / exhaust valve and improve the engine quietness by canceling the vibration of the engine body with unbalanced vibration. A balancer unit that is driven by the power of the crankshaft is also known (see Patent Document 1).

  Here, in the technique disclosed in Patent Document 1, the drive shaft drives the cam shaft and the balancer unit, and an intermediate shaft is disposed on the front surface of the cylinder block to drive the cam shaft and the balancer unit. Driving is performed using three endless drive chains.

  This is for the reason described below. One is when the drive chain drives a high-pressure fuel pump disposed on one side of the engine body, in addition to the camshaft located above the engine body and the balancer unit located below the engine body. In this case, if everything is driven by a single drive chain, the loop shape of the drive chain wound around the crankshaft, camshaft, and balancer unit shaft will increase, and the width of the engine front will be reduced. This is why it gets bigger.

  That is, in order to suppress the width of the front portion of the engine of the drive chain, if the guide means is regulated so that the portion between the shaft portions of the drive chain is placed toward the center of the engine, the curvature increases, A large resistance is generated between the guide means and this causes a mechanical loss.

  The other is that each shaft portion has a predetermined rotational speed ratio of the balancer unit to the crankshaft (requires twice the rotational speed of the crankshaft) and a predetermined rotational speed ratio of the camshaft. However, if a single drive chain is wound around each sprocket in common, the camshaft sprocket must have a larger diameter, and the engine This is because the width of the front part becomes large, and the degree of freedom of arrangement layout of devices around the engine is limited.

  For example, for the latter reason, the camshaft and the balancer unit are driven using three endless drive chains, and the crankshaft and the intermediate shaft are sprocketed with different diameters (number of teeth). Since the number of teeth is adjusted by attaching a different chain and winding a different chain, the sprocket of the cam shaft portion can be made as small as possible.

JP 2003-42230 A

  By the way, in the case where the camshaft and the balancer unit are driven by the crankshaft as described above, each shaft rotates at a predetermined rotation speed ratio with respect to the crankshaft, and the crankshaft and balancer rotate, and the intake and exhaust valves are opened and closed. Is performed at an appropriate timing, the phase of the rotation angle of each axis and the phase of the drive chain must have a predetermined relationship.

  Therefore, when assembling an engine with sprockets having different diameters (number of teeth) coaxially attached to the crankshaft and the intermediate shaft as described above, the sprockets can be easily adjusted from the front of the engine. Is preferably arranged from the front of the engine.

  By the way, a chain cover that covers each drive chain is located in front of each drive chain, and in front of the chain cover, a plurality of auxiliary machines are disposed on the intake side surface of the engine body. The crankshaft is driven via an accessory drive belt.

  Here, as described above, when the camshaft and the balancer unit are driven using a plurality of drive chains, they cannot be arranged on the same plane in the crankshaft direction. According to the position of the engine, it has a staircase shape, and the total length in the front-rear direction of the engine is increased by the amount of protrusion to the front.

  Therefore, depending on the arrangement of the accessory and the accessory drive belt with respect to the chain cover, there is a problem that the total length in the front-rear direction of the engine becomes long, which is disadvantageous in the mountability of the vehicle in the engine room.

  In the present invention, in the case where a plurality of drive chains are arranged in the front-rear direction, the phase alignment between the drive chain and each shaft wound around the drive chain is facilitated, and the total length in the front-rear direction of the engine An object of the present invention is to provide an engine front structure that can shorten the length of the vehicle and improve the mountability of the vehicle in the engine room.

An engine front structure according to the present invention is a front structure of an engine in which a plurality of auxiliary machines are disposed on an intake side surface of an engine main body and driven by an auxiliary machine driving belt by a crankshaft. A balancer unit is disposed inside and driven by the crankshaft via a balancer unit drive chain sprocket and a balancer unit drive chain, and the crankshaft and a camshaft disposed on the cylinder head are connected via an intermediate shaft. The camshaft is driven by a two-stage camshaft drive chain, and the camshaft drive chain has a lower stage than the upper stage on the cylinder block side, and the balancer unit drive chain sprocket is The camshaft drive chain is placed closer to the cylinder block than the lower drive sprocket that drives the lower drive side. A chain cover covering the front of each chain, in response to the engine longitudinal position of each chain, the recessed shape of the lower front cylinder block side of the top front,
The accessory drive belt is disposed on the front surface of the chain cover,
The auxiliary machine drive belt was routed by arranging an idler and a belt tensioner on the chain cover so as to overlap with the placement area on the lower side of the balancer unit drive chain and the camshaft drive chain in front view of the engine. It is characterized by that.

  According to this configuration, the balancer unit drive chain is wound, and the sprocket that is coaxial with the crankshaft has a large diameter, and is arranged on the rear cylinder block side in the engine front view. Then, the lower stage side of the camshaft drive chain is wound around, and the lower stage side drive sprocket, which is coaxial with the crankshaft, has a small diameter and is disposed forward.

  Furthermore, the lower shaft side of the camshaft drive chain is wound around the intermediate shaft, the sprocket that is coaxial with the intermediate shaft has a large diameter, is placed on the rear cylinder block side, and the upper shaft side of the camshaft drive chain is wound around The sprocket that is coaxial with the intermediate shaft has a small diameter and is disposed forward.

  From the above, the meshing position of the crankshaft sprocket and the balancer unit drive chain, the meshing position of the camshaft drive chain with the lower stage, and the meshing position of the intermediate shaft sprocket and the upper stage of the camshaft drive chain Can be visually observed from the front of the engine.

  In addition, the lower shaft side of the cam shaft drive chain is wound around the intermediate shaft and the sprocket that is coaxial with the intermediate shaft has a large diameter, and the upper shaft side of the cam shaft drive chain is wound around and is coaxial with the intermediate shaft. By reducing the diameter of the camshaft, the camshaft sprocket around which the upper side of the camshaft drive chain is wound can be made as small as possible.

  In addition, the chain cover is shaped so that the lower front surface is deeper toward the cylinder block than the upper front surface, and the empty space formed in the longitudinal direction of the engine includes idler, belt tensioner installation space, and auxiliary machine drive belt wiring space. Therefore, the overall length of the engine in the front-rear direction can be shortened.

  In the present invention, the front of the engine refers to the side where the chain cover is disposed and the accessory drive belt is routed, and the longitudinal direction of the engine refers to the cylinder row direction.

  In one embodiment of the present invention, the chain cover covers the balancer unit drive chain and the camshaft drive chain, and one of the auxiliary machines is disposed on the side of the oil pan. In addition, an idler is disposed on the tension drive side of the auxiliary machine drive belt between the auxiliary machine and the crankshaft, and at least a part of the auxiliary machine drive belt and the idler is at the front of the engine with respect to the balancer unit drive chain. It is characterized in that they are arranged in duplicate.

  According to this configuration, at least a part of the accessory drive belt and the idler can be disposed in the empty space formed by the lower front surface of the chain cover that is located behind the cylinder block. Appropriate tension can be applied to the accessory drive belt without extending the overall length of the engine in the front-rear direction.

  In one embodiment of the present invention, the lower stage side of the camshaft drive chain is routed around three sprockets so as to drive the second auxiliary machine arranged on the engine side along with the intermediate shaft. A belt tensioner is arranged on the slack side of the accessory drive belt so that it overlaps with the arrangement area on the lower side of the cam drive chain when viewed from the front of the engine. And

  According to this configuration, the middle portion of the chain cover is recessed to correspond to the routing area on the lower stage side that is located rearward from the upper stage side of the camshaft drive chain at the foremost position. If so, an empty space can be formed in the front-rear direction.

  Therefore, since this empty space can be used as a space for arranging the belt tensioner of the auxiliary machine drive belt, an appropriate tension is applied to the auxiliary machine drive belt without increasing the overall length of the engine in the front-rear direction. Can be granted.

  In one embodiment of the present invention, a plurality of auxiliary machines are arranged substantially linearly in the vertical direction on the intake side surface of the engine body, and the auxiliary machine includes a generator and an air conditioning compressor, The generator is driven by the single accessory drive belt, with the air conditioning compressor disposed on the side of the oil pan and another accessory disposed therebetween.

  According to this configuration, the dimensions in the engine width direction orthogonal to the front-rear direction can be reduced while satisfying the installation conditions of each auxiliary machine.

  In an embodiment of the present invention, the other auxiliary machine is a water pump, and the water pump is driven by an outer surface of the auxiliary machine driving belt.

  According to this structure, the function as an idler which gives tension | tensile_strength with respect to an auxiliary machine drive belt can be combined with a water pump.

  In one embodiment of the present invention, the engine is mounted horizontally with respect to the engine room in the front portion of the vehicle so that the axial direction of the crankshaft is a direction along the vehicle width direction.

  According to this configuration, when a collision occurs, the engine can be mounted with a gap that does not hinder the deformation of the front frame located on both sides in the vehicle width direction, that is, in the longitudinal direction of the engine.

  According to this invention, each axis including the phase alignment between the crankshaft and the balancer unit drive chain, the phase alignment between the camshaft drive chain, and the phase alignment between the intermediate shaft and the camshaft drive chain. It is possible to facilitate the phase alignment between the part and the drive chain.

  Furthermore, the chain cover is shaped so that the lower front surface is deeper toward the cylinder block than the upper front surface, and the empty space formed in the front-rear direction of the engine is used as an installation space for idlers, belt tensioners, and accessory drive belts. Since the overall length of the engine in the front-rear direction can be shortened, the mounting property of the vehicle in the engine room can be improved.

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a front view showing a state in which a chain cover 31 (see FIGS. 3 and 4) is removed at a front portion of an engine 1 according to an embodiment of the present invention. A crankshaft 3 is pivotally supported, and an oil pan 4 is attached below the cylinder block 2.

  The engine body 1 a has a cylinder head 5 placed above the cylinder block 2, and a timing case 6 is attached in front of the cylinder block 2.

  In the engine main body 1a, a crank journal 7 shown in FIG.

  The cylinder block 2 in FIG. 1 is provided with a plurality of cylinders (not shown) arranged in series. A piston (not shown) is slidably incorporated in the cylinder, and is connected to a crankpin 8 of the crankshaft 3 shown in FIG. 2 by a connecting rod (not shown).

  The cylinder head 5 is provided with an intake port and an exhaust port communicating with the cylinder, an intake valve and an exhaust valve (both not shown), respectively, and the intake cam 9 and the exhaust cam 10 shown in FIG. 2 correspond to the cylinder position. The intake camshaft 11 and the exhaust camshaft 12 attached in this manner are supported.

  The engine main body 1a has the crankshaft first and second sprockets 3a and 3b attached to the front end side of the axis of the crankshaft 3, and the intake camshaft drive sprocket on the front end sides of the intake camshaft 11 and the exhaust camshaft 12, respectively. 11a and an exhaust camshaft drive sprocket 12a are attached.

  The crankshaft second sprocket 3b is disposed on the cylinder block 2 side behind the crankshaft first sprocket 3a.

  A first intermediate sprocket 13a that is integrally provided on the front end side in the axial direction of the intermediate shaft 13 is located below the intake camshaft drive sprocket 11a in the vertical direction. Similar to the first intermediate sprocket 13a, the intermediate shaft 13 is provided with a second intermediate sprocket 13b provided integrally with the intermediate shaft 13, and the second intermediate sprocket 13b is the second intermediate sprocket 13b. 1 is arranged on the cylinder block 2 side behind the intermediate sprocket 13a.

  A camshaft drive lower chain 14 is wound around the crankshaft first sprocket 3a and the second intermediate sprocket 13b. Here, the camshaft drive lower chain 14 is also wound around a drive sprocket 15a of the fuel pump 15 on the side of the engine body 1a, and the crankshaft first sprocket 3a and the second intermediate sprocket 13b are connected to each other. The camshaft driven lower chain 14 is stretched in a substantially triangular shape by a total of three sprockets to form a closed planar region, which is a routing area A1.

  Further, the camshaft drive lower chain 14 is pivotally supported by a rotary shaft 17 by a hydraulic tensioner adjuster 16 from the outside of the wiring area A1 on the slack side of the camshaft drive lower chain 14. A tension sufficient to properly transmit the driving force of the crankshaft 3 is always maintained via the tensioner lever 18.

  Further, from the inside of the routing area A1, since the routing position of the camshaft drive lower chain 14 is regulated by the guide member 19, the shape of the camshaft drive lower chain 14 is held in a predetermined shape. It has become.

  A camshaft drive upper chain 20 is wound around the intake camshaft drive sprocket 11a, the exhaust camshaft drive sprocket 12a, and the first intermediate sprocket 13a, and is closed by the cam drive upper chain 20. The planar area thus formed is the routing area A2.

  Further, the camshaft drive upper stage chain 20 is provided on the slack side of the camshaft drive lower stage chain 20 from the outside of the wiring area A2 by a hydraulic tensioner adjuster 21 and is used as a common rotating shaft with the tensioner lever 18. The tension sufficient to properly transmit the driving force of the crankshaft 3 is always maintained through the tensioner lever 22 pivotally supported at 17.

  In addition, on the tension side of the camshaft drive upper chain 20, the guide member 23 restricts the position of the camshaft drive upper chain 20 so that the shape of the camshaft drive upper chain 20 is held in a predetermined shape. It has become so.

  Note that holes 22a are formed at a plurality of locations of the tensioner lever 22, which are bolt holes 6a formed in the timing case 6 to support the engine body 1a with respect to the vehicle body, and in front of the engine. It is formed so as to overlap, so that a bolt can be inserted into the bolt hole 6a and the engine body 1a can be fastened to the vehicle body.

  With the configuration described above, the driving force of the crankshaft 3 is generated by the intake camshaft 11 and the exhaust camshaft 12 by the upper and lower two-stage drive chains of the camshaft drive lower chain 14 and the camshaft drive upper chain 20 via the intermediate shaft 13. And the intake and exhaust valves are opened and closed to open and close the intake and exhaust ports. Here, the camshaft drive lower stage chain 14 is disposed on the rear cylinder block 2 side with respect to the camshaft drive upper stage chain 20.

  By the way, the balancer structure of the engine body 1 a is provided by supporting the balancer shaft 24 in the oil pan 4 in parallel with the crankshaft 3. The balancer shaft 24 includes a first balancer shaft and a second balancer shaft, which have a rotation center substantially parallel to the axial direction of the crankshaft 3 and rotate twice as much as the crankshaft 3. They rotate in opposite directions at a speed. In FIG. 1, only one side of the two balancer shafts is shown.

  The balancer shaft 24 is integrally provided with a balancer shaft drive chain sprocket 25 positioned below in the vertical direction of the crankshaft second sprocket 3b on the front end side in the axial direction. Accordingly, the balancer shaft drive chain sprocket 25 is disposed on the cylinder block 2 side behind the crankshaft first sprocket 3a wound around the camshaft drive lower chain 14.

  A balancer shaft drive chain 26 is wound around the balancer shaft drive chain sprocket 25 and the crankshaft second sprocket 3b, and a flat area closed by the balancer shaft drive chain 26 is formed to form a routing area A3. ing.

  Further, the balancer shaft drive chain 26 is always cranked from the outside of the wiring area A3 on the slack side via a tensioner lever 29 supported by a rotating shaft 28 by a hydraulic tensioner adjuster 27. The tension enough to properly transmit the driving force of the shaft 3 is maintained.

  Further, on the tensioning side of the balancer shaft drive chain 26, the position of the balancer shaft drive chain 26 is regulated by the guide member 30, so that the shape of the balancer shaft drive chain 26 is held in a predetermined shape. It has become.

  With the above-described configuration, the driving force of the crankshaft 3 is transmitted to the balancer shaft drive chain sprocket 25 by the balancer shaft drive chain 26 to drive the balancer unit.

  Here, in the crankshaft first and second sprockets 3a and 3b, the diameter of the crankshaft first sprocket 3a positioned forward is smaller than that of the crankshaft second sprocket 3b positioned rearward and the number of teeth is reduced. However, the number of the first crankshaft sprocket 3a is smaller.

  Further, in the first and second intermediate sprockets 13a and 13b of the intermediate shaft 13, the diameter of the first intermediate sprocket 13a positioned forward is smaller than that of the second intermediate sprocket 13b positioned rearward. As for the number of teeth, the first intermediate sprocket 13a has a smaller number.

  Thus, when transmitting the driving force of the crankshaft 3 to the intake camshaft drive sprocket 11a and the exhaust camshaft drive sprocket 12a rotating at a low speed with respect to the crankshaft 3, the crankshaft 3 has a small diameter. The intermediate shaft 13 has a large diameter and a large number of teeth with respect to the camshaft drive lower chain 14 that uses the crankshaft first sprocket 3a having a small number of teeth as an output source and directly transmits the driving force from the crankshaft 3. The second intermediate sprocket 13b receives a driving force, relays the first intermediate sprocket 13a having a smaller diameter and a smaller number of teeth than the second intermediate sprocket 13b, and the camshaft driving upper chain 20 causes the intake camshaft driving sprocket. 11a, the exhaust camshaft drive sprocket 12a is driven to rotate.

  Therefore, since the number of teeth is adjusted by the intermediate shaft 13 in the middle from the crankshaft 3 to the intake camshaft drive sprocket 11a and the exhaust camshaft drive sprocket 12a, the intake camshaft drive sprocket 11a and the exhaust camshaft drive sprocket are adjusted. The diameter of 12a can be reduced.

  Incidentally, as shown in FIG. 1, the crankshaft first and second sprockets 3a and 3b, the intake camshaft drive sprocket 11a, the exhaust camshaft drive sprocket 12a, the first intermediate sprocket 13a, the fuel pump sprocket 15a, the balancer. Marking 3c, 3d, 11b, 12b, 13c, 15b, and 25a are engraved in the vicinity of the periphery of the shaft drive chain sprocket 25, while the camshaft drive lower stage, upper stage chains 14 and 20, and balancer shaft drive chain. 26, markings 14a, 14b, 20a, 20b, 20c, 26a, and 26b are engraved on the surface portions having these thicknesses.

  This is because, in each member driven by the crankshaft 3, each shaft is rotated at a predetermined rotation speed ratio with respect to the crankshaft 3, and the rotation timing of the crankshaft 3 and the balancer shaft 24 and the opening and closing timings of the intake and exhaust valves are adjusted. This is a mark for setting the phase of the rotation angle of each axis and the phase of the drive chain in a predetermined relationship in order to make it appropriate. For example, as shown in the figure, the drive chain is wound around each sprocket. If the positions of the markings coincide with each other, phase matching can be performed.

  With the above configuration, in each of the crankshaft 3 and the intermediate shaft 13, the small-diameter sprockets 3a and 13a are disposed in front of the large-diameter sprockets 3b and 13b. Also in 3d and 13c, those positions can be visually observed by the front view of the engine main body 1a.

  Accordingly, in the assembly process of the engine body 1a, the phase alignment operation of the marking 13c and the marking 20a of the first intermediate sprocket 13a having a smaller diameter than the second intermediate sprocket 13b, the crankshaft having a smaller diameter than the crankshaft second sprocket 3b. Both the phase alignment operation of the marking 3c and the marking 14a of the first sprocket 3a and the phase alignment operation of the marking 3d and the marking 26a of the crankshaft second sprocket 3b are performed smoothly without blocking the field of view by other sprockets. be able to.

  By the way, as described above, in order to realize the reduction in the diameter of the intake and exhaust camshaft drive sprockets 11a and 12a and the smoothing of the phase alignment operation, as shown in FIGS. The upper camshaft drive upper chain 20 is disposed at the foremost side, and the camshaft drive lower chain 14 and the balancer shaft drive chain 26 are disposed at a deep position on the cylinder block 2 side below the engine body 1a. It has become.

  Therefore, as shown particularly in FIG. 2, empty spaces having a width in the front-rear direction are formed below the camshaft drive upper chain 20 and below the camshaft drive lower chain 14.

  Therefore, in the present invention, the chain shown in FIG. 3 that covers the front surface of each drive chain 14, 20, 26 corresponding to the position in the front-rear direction of the engine body 1a of each drive chain 14, 20, 26 is shown. As shown in FIG. 4 which is a sectional view taken along the line XX of FIG. 3, the cover 31 has a shape in which the lower front surface is recessed toward the cylinder block 2 from the upper front surface. In addition, as shown in FIGS. 3 and 5, the empty space in the lower part formed in the front-rear direction of the engine main body 1 a includes a first idler 37, an installation space for the belt tensioner 42 which will be described in detail later, and an accessory drive belt 43. It was set as a routing space.

  The chain cover 31 covers the front surfaces of the power transmission systems such as the drive chains 14, 20, 26 and the sprockets 3a, 3b, 11a, 12a, 13a, 13b, 15a, 25, etc. The configuration, operation, etc. will be described with reference to FIGS.

  The chain cover 31 is integrally formed with a mount seat 32 having a shape protruding outward, and the mount seat 32 supports the engine body 1a via a vehicle body side bracket or the like (not shown).

  A plurality of bolt boss portions 33 are formed on the back surface of the wall portion of the chain cover 31, and the bolt boss portions 33 protrude rearward from the back surface of the wall portion of the chain cover 31 and are inserted into the bolt holes 6 a (see FIG. 1) of the timing case 6. In order to communicate the bolt hole 34, a joint surface 33 a that joins the front surface of the timing case 6 is provided.

  The bolt boss part 33 and the bolt hole 34 are formed at a plurality of locations in two upper and lower stages, and the front end of the upper side bolt hole 34 on the chain cover 31 is located on the mount seat 32.

  Bolts are passed from the mount seat 32 to the bolt holes 34, and each bolt is screwed into the bolt hole 6 a of the timing case 6 and fastened.

  On the front surface of the chain cover 31, as shown in FIG. 3, an auxiliary machine drive pulley 36, a first idler 37, an air conditioner, which are integrally attached to the crankshaft 3 passing through a bearing hole 35 formed in the chain cover 31. A compressor 38, a water pump 39, an alternator 40, a second idler 41, and a belt tensioner 42 are disposed, and an accessory drive belt 43 is wound around these.

  The belt tensioner 42 is driven by the hydraulic tensioner adjuster 44 to rotate an arm 46 extending across the accessory drive belt 43 around the turning shaft 45 to thereby move the accessory tension belt adjuster 44 to the accessory drive belt 43. It is possible to advance and retreat.

  1 and FIG. 3, in the engine front view, in the embodiment of the present invention, the camshaft drive lower chain 14 and the balancer shaft drive chain 26 are overlapped with the routing areas A1 and A3. A single idler 37 and a belt tensioner 42 are disposed on the chain cover 31, and an accessory drive belt 43 is routed.

  That is, since the first idler 37 and the belt tensioner 42 can be accommodated in the empty space below the chain cover 31 formed in the front-rear direction of the engine body 1a, the side view of FIG. As shown in FIG. 2, the extension of the member to the front of the engine body 1a can be suppressed, and the overall length of the engine 1 in the front-rear direction can be shortened.

  Thus, since the total length of the engine 1 in the front-rear direction can be shortened, the mountability of the vehicle in the engine room can be improved, and the degree of freedom in layout including peripheral devices can be increased.

  In FIG. 3, an air conditioning compressor 38, which is one of the auxiliary machines, is disposed on the side of the oil pan 4, and an auxiliary machine drive between the air conditioning compressor 38 and the crankshaft 3 is performed. A first idler 37 is arranged on the tension side of the belt 43, and at least a part of the auxiliary machine drive belt 43 and the first idler 37 is overlapped with the balancer shaft drive chain 26 when viewed from the front of the engine. Has been. That is, the first idler 37 is disposed at a position in the empty space below the chain cover 31 where the overhang of the engine 1 to the front can be minimized.

  As a result, an appropriate tension can be applied to the accessory drive belt 43 without extending the overall length of the engine 1 in the front-rear direction.

  Furthermore, a belt tensioner 42 disposed on the slack side of the accessory drive belt 43 is disposed so as to overlap the routing area A1 of the camshaft drive lower stage chain 14 when viewed from the front of the engine.

  As a result, the middle part of the chain cover 31 is formed in the middle part of the chain cover 31 so as to correspond to the wiring area A1 located deeper than the wiring area A2 of the camshaft drive upper chain 20. The belt tensioner 42 and the arm 46 can be disposed in the empty space.

  Therefore, an appropriate tension can be applied by the accessory drive belt without extending the overall length of the engine 1 in the front-rear direction. In addition, since the belt tensioner 42 and the arm 46 are arranged so as to overlap with the wiring area A1 that extends in a substantially triangular shape, the auxiliary machine driving pulley 36, the first idler 37, It can be positioned away from the air conditioning compressor 38. Therefore, there is an advantage that the rotation range of the arm 46 can be expanded.

  Furthermore, the alternator 40 having a condition that it is not preferable to install it in a wet environment is preferentially disposed upward, the air conditioning compressor 38 is disposed on the side of the oil pan 4, and the vertical In the direction, a water pump 39 is disposed between the air conditioning compressor 38 and the alternator 40 as another auxiliary machine.

  Thereby, in particular, the dimensions in the width direction (left-right direction in FIG. 3) of the engine 1 orthogonal to the front-rear direction can be reduced while satisfying the installation conditions of the alternator 40.

  Furthermore, although the water pump 39 is arranged to be driven by the outer surface of the accessory drive belt 43, the water pump 39 has a function as an idler for applying tension to the accessory drive belt 43. It can be combined.

  This is because the rotating body driven on the outer surface of the auxiliary machine driving belt 43 preferably has a small rotational torque and a small load on the auxiliary machine driving belt 43, and the water pump 39 is more preferable. It is.

  Here, the first idler 37 and the belt tensioner 42 are accommodated in an empty space below the chain cover 31 formed in the front-rear direction of the engine body 1a, thereby realizing a reduction in the overall length of the engine 1 in the front-rear direction. The present invention is particularly applicable to the case where the engine 1 is shown in FIG. 6 mounted sideways with respect to the engine room at the front of the vehicle so that the axial direction of the crankshaft 3 is along the vehicle width direction. Has a remarkable effect.

  That is, the engine 1 is supported by two front frames 47, 47 extending in the vehicle front-rear direction on both sides of the engine room in the left-right direction (vehicle width direction) via the mount seat 32 (see FIG. 3). As a result of shortening the overall length L1 in the front-rear direction, the vehicle of the power unit that combines the total length L1 and the overall length in the vehicle width direction of the transmission 48 attached to one side of the vehicle of the engine 1 (the right side in FIG. 6) The total length L2 in the width direction can be shortened.

  Accordingly, the widest possible distances L3 and L4 can be secured between the engine 1 and the transmission 48 and the front frames 47 and 47 without increasing the size of the vehicle body in the vehicle width direction.

  Even if the vehicle body collides with an object and is crushed and deformed, as shown in the figure, even if the width of the left and right front frames 47 and 47 is increased from L5 to L5a and L5b, the engine 1 is crushed and deformed by the front frames 47 and 47b. There is an effect of not inhibiting.

  In the above-described embodiment, the camshaft drive lower chain 14 is stretched in a substantially triangular shape by the crankshaft first sprocket 3a, the second intermediate sprocket 13b, and the fuel pump drive sprocket 15a. Although the area A1 is formed, the crankshaft first sprocket 3a and the second intermediate sprocket 13b form a wiring area for the camshaft driven lower chain 14, and the crankshaft second sprocket 3b is described above. The arrangement area of the balancer shaft drive chain 26 may be constituted by the fuel pump drive sprocket 15a and the balancer shaft drive chain sprocket 25 having a different number of teeth from the embodiment.

  As a result, it is possible to expand the wiring area of the drive chain disposed behind the cylinder block 2, so that the shape of the chain cover 31 is recessed toward the cylinder block 2 corresponding to the wiring area. The lower front part may be expanded.

  Accordingly, since the lower empty space formed in the front-rear direction of the engine body 1a can be expanded, in addition to the auxiliary machine described in the first embodiment, a different auxiliary machine is added to the empty space. It becomes possible to arrange.

  Other functions and effects are the same as in the first embodiment.

In correspondence between the configuration of the present invention and the above-described embodiment,
The balancer unit drive chain sprocket of the present invention corresponds to the balancer shaft drive chain sprocket 25,
Similarly,
The balancer unit drive chain corresponds to the balancer shaft drive chain 26,
The cam shafts correspond to the intake cam shaft 11 and the exhaust cam shaft 12,
The lower stage drive sprocket corresponds to the crankshaft first sprocket 3a,
The second auxiliary machine corresponds to the fuel pump 15,
The generator corresponds to the alternator 40,
The present invention is not limited only to the configuration of the above-described embodiment, and many embodiments can be obtained.

The front view which shows the state which removed the chain cover in the engine front part which concerns on embodiment of this invention. The side view which shows each drive chain, a crankshaft, an intake, and an exhaust camshaft among the engine front parts shown in FIG. FIG. 2 is a front view showing a configuration in which each drive chain is covered with a chain cover in the front portion of the engine shown in FIG. XX arrow sectional drawing in FIG. The side view of the engine front part shown in FIG. FIG. 4 is a plan view showing a state in which the engine having the front structure shown in FIG. 3 is mounted horizontally with respect to the engine room at the front of the vehicle so that the axial direction of the crankshaft is in the direction along the vehicle width direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a ... Engine main body 2 ... Cylinder block 3 ... Crankshaft 4 ... Oil pan 5 ... Cylinder head 11 ... Intake cam shaft 12 ... Exhaust cam shaft 13 ... Intermediate shaft 14 ... Cam shaft drive lower chain 15 ... Fuel pump 20 ... Cam shaft drive Upper chain 25 ... balancer shaft drive chain sprocket 26 ... balancer shaft drive chain 37 ... first idler 38 ... air conditioning compressor 39 ... water pump 40 ... alternator 41 ... second idler 42 ... belt tensioner 43 ... auxiliary drive belt A1, A2, A3 ... Routing area

Claims (6)

A front structure of an engine in which a plurality of auxiliary machines are disposed on the intake side of the engine body and driven by an auxiliary machine driving belt by a crankshaft,
A balancer unit is arranged in the oil pan and driven by the crankshaft through the balancer unit drive chain sprocket and the balancer unit drive chain,
The crankshaft and the camshaft disposed on the cylinder head are connected via an intermediate shaft, and the camshaft is driven by a two-stage camshaft drive chain.
In the above camshaft drive chain, the lower stage side is arranged on the cylinder block side than the upper stage side,
The balancer unit drive chain sprocket is disposed closer to the cylinder block than the lower drive sprocket that drives the lower drive side of the camshaft drive chain.
The chain cover that covers the front of each chain is shaped so that the lower front is deeper toward the cylinder block than the upper front, corresponding to the position of each chain in the longitudinal direction of the engine.
The accessory drive belt is disposed on the front surface of the chain cover,
The auxiliary machine drive belt was routed by arranging an idler and a belt tensioner on the chain cover so as to overlap with the placement area on the lower side of the balancer unit drive chain and the camshaft drive chain in front view of the engine. Engine front structure. The chain cover covers the balancer unit drive chain and the camshaft drive chain,
One of the plurality of accessories is disposed on the side of the oil pan, and an idler is disposed on the tension side of an accessory drive belt between the accessory and the crankshaft,
The engine front structure according to claim 1, wherein at least a part of the accessory drive belt and the idler are disposed so as to overlap the balancer unit drive chain in a front view of the engine. The lower stage side of the camshaft drive chain is routed so as to form a routing area wound around three sprockets so as to drive the second auxiliary machine arranged on the engine side along with the intermediate shaft. ,
The front structure of an engine according to claim 1 or 2, wherein a belt tensioner is disposed on the slack side of the accessory drive belt so as to overlap with a lower wiring area of the cam drive chain in a front view of the engine. A plurality of auxiliary machines are arranged in a substantially straight line in the vertical direction on the intake side surface of the engine body, and the auxiliary machines include a generator and an air conditioning compressor,
4. The apparatus according to claim 1, wherein the power generator is disposed upward, the air conditioning compressor is disposed laterally of the oil pan, and another auxiliary device is disposed therebetween, and is driven by the single accessory driving belt. 5. The front structure of the engine described in the item. The other auxiliary machine is a water pump,
The engine front structure according to claim 4, wherein the water pump is driven by being wound around an outer surface of the accessory drive belt. The engine according to any one of claims 1 to 5, wherein the engine is mounted horizontally with respect to an engine room in a front portion of the vehicle such that an axial direction of the crankshaft is a direction along a vehicle width direction. Front structure.

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