CN100342122C - Integrated chain case structure with water pump - Google Patents

Abstract

A chain case (6) for an engine (1), comprising a front wall (601), an end inner wall (18f) disposed toward one end of a cylinder block (2) at predetermined intervals, and left and right side walls (602) , extending from the peripheral edge of the front wall (601), which is superimposed on the side wall of the cylinder block to be integrally connected thereto, and forms a chain housing chamber (13) when integrally connected to the cylinder block, which is used for the engine ( 1) The chain case (6) is characterized in that: the pump chamber (161) is formed on the thickened part (28), and the thickened part (28) is formed from the left side between the rear wall surface (fc) and the front wall surface (fd) of the casing. 1. A part of the right side wall (602) protrudes, wherein the rear wall surface (fc) of the housing is superimposed on the opposite surface (F) of one end of the side wall of the cylinder body, and the front wall surface (fd) is located opposite to the end surface (F) side, it is also characterized in that the pump cover (45) is used to close the through hole to form a water pump (16), and the pump cover (45) makes the pump shaft (44) rotatably fastened, and the pump shaft is assembled in the pump chamber ( The pump impeller (43) in 161) is integrated as a whole.

Description

Chain case structure with integrated water pump

technical field

The present invention relates to a chain case structure, which accommodates a chain transmission system for connecting the engine crankshaft and a valve drive system or a valve mechanism, in particular to a chain case structure integrated with a water pump, and the chain case structure is integrally fixed to one end of a cylinder block on the cylinder side wall.

The present invention also relates to a chain-type rotary transmission system that uses an endless chain to transmit the rotation of the engine crankshaft to the valve train or valve train via the camshaft, and more particularly to a chain housing structure for covering a chain tensioner that applies tension to the chain .

Background technique

The engine uses a rotary transmission mechanism to transmit part of the rotational force of the crankshaft arranged at the lower part of the engine cylinder block to the valve mechanism to open the intake valve and exhaust valve provided on the cylinder head side. Both belt-type rotary drives and chain-type rotary drives are suitable as rotary drives. Of the two devices, although the belt-type rotary transmission mechanism does not require lubricating oil due to the use of rubber parts for meshing drive, its durability is not as good as that of the chain-type rotary transmission mechanism, and the chain-type rotary transmission mechanism uses metal-to-metal contact. Lubricating oil is required for meshing, but its durability also becomes better.

Here, in the case of using a chain-type rotary transmission mechanism that can ensure durability, the chain case for housing the mechanism needs to be oil-resistant, and therefore, in many cases, a chain case of plastic rather than metal is used, such as , using aluminum alloy chain case.

Furthermore, in the engine, by circulating the coolant along the coolant supply system including the water jacket in its cylinder block and cylinder head, the engine block can be kept at the proper temperature for the durability of the various hot parts .

In the conventional method, in many cases, a water pump for circulating the coolant along the coolant circulation system is integrally installed on the cylinder block, and part of the rotational force of the crankshaft is transmitted to the water pump through a chain-type rotary transmission system, etc. shaft.

An example of an engine is disclosed in JP-A-2002-303136 in which a water pump is accommodated in a recess in a side wall at one end of a cylinder block so as to divide coolant to be simultaneously supplied into the cylinder head and the cylinder block.

The chain-type rotary transmission mechanism or device includes a chain tensioner, which transmits tension to the chain to suppress noise generation. That is, the chain tensioner includes a chain tensioner main body having a plunger and a chain guide, the plunger is extended to work when receiving spring force or hydraulic pressure, and when receiving the thrust of the plunger of the chain tensioner main body , the chain guide pivots to change its position, thereby transferring tension to the chain. Among them, in the main body of the chain tensioner, the spring for always applying pressure to the plunger, the hydraulic supply passage and the safety valve for eliminating excessive hydraulic pressure are all accommodated in a housing, which is bolted to the On the wall of the body and one end of the cylinder head, the main body of the chain tensioner has high precision so that the chain tension is automatically maintained at an appropriate level.

Note that JP-A-2003-35116 discloses a chain tensioner mechanism for transmitting rotation of a crankshaft rotatably supported in a cylinder block of a V-type engine having a timing chain to a rotatably supported First and second camshafts on first and second cylinder heads. It is disclosed therein that a tensioner member for applying a predetermined tension to the timing chain and a chain adjuster are provided on one cylinder group of the cylinder block.

Contents of the invention

Incidentally, as in the example of JP-A-2002-303136, the pump chamber should be formed in the cylinder body somehow, and the recessed part constituting the pump chamber should be formed with the cylinder, water jacket, Crankcase and other places where no interference occurs, which complicates the structure of the inner wall parts of the cylinder near the pump chamber, increases the risk of shrinkage cavities in the cylinder block material during the die-casting process, and increases the failure rate.

In particular, when casting the cylinder block, it is difficult to ensure the accuracy of the pump chamber. Therefore, it is necessary to ensure the accuracy of the pump chamber by cutting the recessed part after its die-casting. Therefore, many machining man-hours are added, resulting in an increase in cost.

The present invention is proposed based on the problems existing in the conventional examples, and an object thereof is to provide a chain housing structure integrated with a water pump, which does not require machining on the side of the cylinder block and can control the failure rate and increase in cost.

Incidentally, as disclosed in JP-A-2003-35116, in the case where the chain and the chain tensioner are assembled in such a manner as to extend between the cylinder block and the cylinder head, they are housed in the chain housing chamber, The chain housing chamber is formed by installing the chain case. However, in the event that the chain and chain tensioner need to be replaced or periodically inspected, in order to open the chain housing chamber, the chain case needs to be removed from the cylinder block and cylinder head.

In particular, in order to check whether the chain tensioner applies tension to the chain so that it is in a normal state, or to replace the main body of the chain tensioner, it is necessary to check the protruding action and the amount of protruding of the chain tensioner, each time the inspection is performed or Any replacement requires removal of the chain case from the cylinder block and cylinder head side. This significantly reduces the efficiency of the inspection work and needs to be improved.

The present invention is made based on the above problems, and an object thereof is to provide a chain case structure that facilitates inspection or replacement of a chain tensioner without removing the chain case.

According to a first aspect of the present invention, there is provided a chain housing structure integrated with a water pump, comprising a chain housing installed at an end of a cylinder head and having a housing chamber for housing a rotary transmission mechanism provided on a cylinder block, and A water pump installed in a chain case, the chain case structure integrated with the water pump is characterized by including: a thickened portion extending from a part of the outer surface of the chain case, which has a wall thickness thicker than that of the housing chamber; a through hole , formed in the thickened portion, capable of accommodating the impeller of the water pump penetrating therein; and a cover member for closing the through hole to form the vortex chamber of the water pump.

According to a second aspect of the present invention, there is provided the water pump integrated chain case structure according to the first aspect of the present invention, characterized in that the cover member supports the impeller of the water pump.

According to the third aspect of the present invention, there is provided the chain case structure integrated with the water pump according to the first aspect of the present invention, characterized in that the discharge channel recess of the water pump extends from the through hole to the thickened portion, so that a single The seal seals the discharge passage recess and the through hole from the cylinder block.

According to the fourth aspect of the present invention, there is provided the chain case structure integrated with the water pump according to the first aspect of the present invention, characterized in that the bracket for supporting the engine is integrally provided on the thickened part to form a discharge passage recessed part s position.

According to a fifth aspect of the present invention, there is provided the chain case structure integrated with a water pump according to the first aspect of the present invention, characterized in that an opening is formed at a predetermined position in the chain case, the predetermined position faces toward the chain case accommodated in the chain case The installation location of the chain tensioner, the opening is used to remove the chain tensioner.

According to a sixth aspect of the present invention, there is provided the chain case structure integrated with a water pump according to the fifth aspect of the present invention, characterized in that a stopper is provided near the opening, and the stopper protrudes from the position for to prevent the chain tensioner from falling.

According to a seventh aspect of the present invention, there is provided a chain case structure integrated with a water pump according to the fifth aspect of the present invention, characterized in that a normally closed cover for closing the opening is provided, the stopper is a band for the machine screw The protrusion of the thread that is used to secure the normally closed cover to the chain case.

According to the first aspect of the present invention, in the case where the pump chamber is formed in the cylinder block, cutting work (post-processing) is not required after die-casting, whereby the cost can be reduced as much as possible by such a simplified working process. Furthermore, in the case where a pump chamber having a relatively complicated structure is formed in the cylinder block, the risk of shrinkage cavities in the material of the cylinder block can be reduced, so that the defective rate of the final product can be reduced. Also, since the pump chamber is formed in the thickened portion, the rigidity of the chain case itself can be increased while suppressing an increase in the weight of the thickened portion.

According to the second aspect of the present invention, since the cover member which is the cover of the pump chamber doubles as the supporting member of the impeller of the water pump, this contributes to reducing the number of included parts.

According to the third aspect of the present invention, both the coolant sealing performance of the discharge passage recess and the side of the through hole and the oil sealing performance of the chain housing chamber can be maintained, and the oil/coolant boundary sealing surface and the single seal can function as a seal. effect. In particular, the coolant sealing margin on the side of the through hole and the sealing margin on the side of the chain housing chamber can overlap with each other, thereby forming a single sealing line, and the thickened portion with the discharge passage recess and the through hole is in the engine The lateral protrusion of the engine can be smaller, which helps to keep the engine as compact as possible in size.

According to the fourth aspect of the present invention, the rigidity of the engine mount can be increased.

According to the fifth aspect of the present invention, since the chain tensioner can be detached from the chain accommodating chamber when the normally closed opening on the chain case is opened, the chain tensioner can be easily replaced without removing the chain case, Or as an easy inspection job, check that the chain tensioner is properly applying tension to the chain.

According to the sixth aspect of the present invention, even in the case where the detached chain tensioner falls due to an operation error, the stopper provided in a protruding manner can suppress the falling to a minimum, thereby The additional work of opening the chain housing chamber to take out the chain tensioner by removing the chain case can be eliminated.

According to the seventh aspect of the present invention, the threaded protrusion formed on the chain case can double as a stopper, thereby reducing the number of parts and reducing the product cost.

Description of drawings

1 is a schematic rear view of an engine to which an engine chain case according to a first embodiment of the present invention is applied;

Figure 2 is a schematic side view of the engine shown in Figure 1;

Figure 3 is a rear side view of the chain case of the engine shown in Figure 1;

Fig. 4 is an enlarged sectional view of main parts of the engine cylinder block shown in Fig. 1;

Figure 5 is an exploded perspective view of one end of the chain housing and engine block shown in Figure 1;

6 is a schematic rear view of an engine to which a chain case structure according to a second embodiment of the present invention is applied;

Figure 7 is a schematic side view of the engine shown in Figure 6;

Figure 8 is a rear side view of the chain case shown in Figure 6;

Figure 9 is an enlarged front view of the main body of the chain tensioner shown in Figure 6; and

Fig. 10 is an exploded cutaway view of the chain case, the cylinder head and one end of the cylinder block shown in Fig. 6 .

Detailed ways

first embodiment

Fig. 1 and Fig. 2 show a kind of automobile four-stroke gasoline engine (abbreviated as engine 1 hereinafter), on which the engine chain case according to the embodiment of the present invention is applied.

In the engine 1, the cylinder head 3 and the cylinder head cover 4 are arranged on the upper side of the cylinder block 2, the oil pan 5 is arranged on the lower side of the cylinder block 2, and the chain case 6 is arranged on one end of the cylinder block 2, whereby these The engine components are interconnected as a whole to form the engine airframe. In addition, a plurality of cylinders S are arranged in the cylinder block 2 and the cylinder head 3 . The intake of the intake gas drawn into the combustion chamber (not shown) located in the cylinder S and the exhaust of the exhaust gas discharged from the combustion chamber are performed through the various components of the intake and exhaust system and the valve train (both not shown). control, and the crankshaft 7 is driven to rotate by the output energy of the combustion chamber received by the piston (not shown).

A pair of camshafts 8 (refer to FIG. 2 ), which constitute a part of a valve train (not shown), are rotatably supported by a plurality of bearings (not shown) inside the cylinder head 3 and head cover 4 . The camshaft sprocket 9 is integrally connected to one end of the camshaft 8 . In particular, the rotation of the crankshaft 7 is transmitted to the sprocket 9 on the intake camshaft through the chain 12 and the timer TM, which advances and retards the timing of valve opening and closing.

A skirt 201 is formed on the lower part of the cylinder block 2, and the lower opening of the skirt 201 is closed by the oil pan 5 to form a crankcase. The cylinder block 2 is an aluminum alloy die-casting product. The crankshaft 7 is arranged in the crankcase, and is rotatably supported on a plurality of bearings (not shown). A crank sprocket 11 , an internal gear (not shown) of an oil pump 29 to be described later, and a crank pulley 10 are integrally connected to one end of the crankshaft 7 . An endless timing chain (hereinafter, simply referred to as chain 12 ) extends between crankshaft sprocket 11 and camshaft sprocket 9 and is limited in deflection by a tensioner (not shown). The chain 12 is accommodated in a chain accommodating chamber 13 formed between one end of the cylinder block 2 and a chain case 6 provided at the same end of the cylinder block 2 . The cylinder head 3 is an aluminum alloy die-casting product, and an inner cavity 20 is formed inside the cylinder head 3 for accommodating a water jacket 42 on the side of the cylinder head and a valve train VD (refer to FIGS. 1 and 2 ).

In the engine 1, the radiator 14, the thermostat 15, and the water pump 16 are components of the coolant circulation system R, and are installed inside or near the outer wall of the engine body. In the cylinder block 2, a plurality of vertical (in the vertical direction Z) cylinders S are arranged at predetermined intervals along the axial direction X of the engine, and each cylinder S is continuously surrounded by a water jacket 17 on the block side.

One end side (lower side wall in FIG. 4 ) of the cylinder block 2 forms an end inner wall 18 , the left and right sides of which protrude to form extensions 18 g. The extension end of the extension part has a flange part which is placed on the connecting flange part 601 of the chain case 6 and fixed thereto by bolts (not shown).

As shown in Figures 1 and 4, the convex wall portion 25 protrudes from the rear outer wall 24b and an extension portion 18g where they overlap each other in the transverse direction Y of the cylinder, and the water pump 16 and the thermostat 15 are arranged on the convex wall portion 25. The proximal side, so that the two are close to each other.

The radiator 14 is a device for dissipating heat, which is connected to the outlet 19 of the cylinder head 3 with the upper hose 21 and connected to the inlet 152 of the thermostat 15 through the lower hose 22 . The outlet 19 is divided so as to be reconnected to the outflow chamber 151 of the thermostat 15 via a short-circuit hose 23 .

The outflow chamber 151 in the thermostat 15 communicates with the pump chamber 161 through the inflow passage 26 formed in the convex wall portion 25 protruding from the rear side outer wall 24 b of the cylinder block 2 . Note that when the temperature of the coolant is high, the thermostat 15 constitutes a coolant selection device, and the inflow chamber 152 communicates with the outflow chamber 151 through a heat-sensing selection valve (not shown).

A flat one-end facing surface F (part of the cylinder outer wall) is formed on the convex wall portion 25, which faces one end of the cylinder block 2 (downward in FIG. 4 ), and the same surface is also continuously formed on the left and right extensions. 18g on. The case rear wall surface fc of the chain case 6 is tightly superimposed on the one end facing surface F thus formed.

As shown in Figures 1 and 4, the chain case 6 has a front wall 602 and left and right connecting flanges 601 that are substantially continuous in the vertical direction, and therefore has a concave cross section when viewed from the top, so that when connected to one end pair When facing the face F, the central chain accommodation chamber 13 can be formed. Moreover, the chain case 6 is made of aluminum alloy, so that the precision of the finished product can be kept high. In addition, the central lower part of the front wall 602 is formed with a through hole 46 (refer to FIG. 3 ), the crankshaft 7 passes through the through hole, and the same central lower part on the inner wall of the front wall 602 is provided with an oil pump 29, which constitutes an oil circulation system. part of the OS. Moreover, a thickened portion 28 is continuously formed on the portion of the front wall facing the convex wall portion 25, the water pump 16 is disposed on the thickened portion 28, and an engine bracket 49 is formed on the convex end of the upper front wall. Note that in FIG. 5, reference numeral "h" denotes an inspection hole, which is closed with a cover i.

The upper end edges of the front wall 602 of the chain case 6 and the left and right side walls 601 of the above-mentioned structure are closely connected to the downward peripheral edge portion of the cylinder head cover 4 at one end of the cylinder head cover, and the lower end edges are closely connected to the cylinder head cover. On the connecting flange 501 of the oil pan 5 at one end thereof. With this configuration, the chain accommodating chamber 13 is kept in a tightly closed state, thereby facilitating the supply of oil circulation to the chain 12 .

A fastening surface 491 is formed at an upper protruding end of the thickened portion 28 , and a plurality of fastening bolts 51 are provided to protrude upward from the upper protruding surface 491 . A fastening hole is provided at the protruding end of the connecting frame 52, which extends from the inner wall surface of the engine room (not shown), and is properly fixed to the fastening bolt 51, thereby, by fastening the nut n to the fastening Bolts 51 , so that the connecting frame 52 is integrally connected to the fastening surface 491 .

Thus, the engine body side is supported on the vehicle body side (not shown) by the support member constituted by the link bracket 52 and the engine bracket 49 . Here, the engine bracket 49 is a part of the thickened part 28, and its rigidity is relatively large, so sufficient strength and durability can be maintained, and since the chain case 6 also serves as the engine bracket 49, the number of parts can be reduced as much as possible.

As shown in Figures 3 and 4, the water pump 16 includes a pump chamber 161, a pump impeller 43, a pump shaft 44 and a pump cover 45 (cover part), wherein the pump chamber 161 is a through hole formed in the thickened portion 28, The pump impeller 43 is accommodated in the pump chamber 161, the water pump shaft 44 is integrated into the pump impeller 43, the water pump shaft 44 passes through the pump outer cover 45, and can rotate freely therein, and the pump outer cover 45 is fastened to the thickened part 28 with bolts On the front wall fd.

A pump chamber 161 is formed in the thickened portion 28, which extends between the housing rear wall surface fc and the front wall surface, wherein the rear wall surface fc is located on the rear side of the thickened portion 28, and the front wall surface is located on the opposite side thereof, the pump chamber 161 is connected to the inflow The passage 26 communicates, and the inflow passage is located on the side where the raised wall 25 is located. Note that the discharge passage 162 on the case side is formed extending from a part of the side wall of the pump chamber 161 .

As shown in Fig. 4 and Fig. 5, the pulley 40 is installed on the outer end of the pump shaft 44, and the pump shaft is rotatably installed in the pump outer cover 45, and the crankshaft pulley 10 of the crankshaft 7 passes through the ring belt 20 and The pulley 40 is connected so as to drive the water pump 16 when the engine is driven, so that the coolant can be circulated and supplied into the coolant circulation system R. As shown in FIG.

Note that, as shown in FIGS. 3 and 4 , the discharge passage 162 on the housing side passes through the extension passage 27 and the branch portion 47 formed inside the convex wall portion 25 to the cylinder head side water jacket 42 provided on the cylinder head side and the water jacket provided on the cylinder head side. Coolant is supplied to the cylinder block side water jacket 17 on the cylinder block side. The coolant flowing into the block side water jacket 17 enters from the branch portion 47 , can then flow to the cylinder head side water jacket 42 , and then flows to the outlet 19 through the communication passage 48 .

Incidentally, as shown in FIG. 3, in the chain case 6, the chain housing chamber 13 provided along the oil circulation system OS and the pump chamber 161 and the case side discharge passage 162 provided along the coolant circulation system R to pass the oil/ The narrower gaps of the coolant boundary closure surfaces fs are formed in such a way that they face each other. Also, an end facing surface F on the cylinder block 2 side and an oil/coolant boundary seal surface fs on the chain case 6 side are in close contact with each other through a single seal 50 (refer to FIG. 4 ), and then fixed with fastening bolts. In this way, the oil/coolant boundary sealing surface fs serves as the oil sealing surface of the chain housing chamber, and the same boundary sealing surface also serves as the coolant sealing surface of the pump chamber 161 and the casing side discharge passage 162, so that the single seal 50 can realize two sealing functions to oil and coolant.

In addition, by making the coolant seal allowance on the pump chamber 161 side coincide with the oil seal allowance on the chain storage chamber 13 side, the oil/coolant seal surface fs can form a single sealing strip, therefore, there is a chain storage chamber. 13 (exhaust passage recess) and the thickened portion 28 of the pump chamber 161 (through hole) protrude in the engine transverse direction Y to such an extent that the engine can be made correspondingly compact in size.

The oil pump 29 for the oil circulation system OS is installed on the central lower portion of the front wall 601 of the chain case 6 .

The oil pump 29 includes a pump casing 31 formed by protruding the periphery of the through hole 46 formed in the front wall 602 outward, and a pump disk 32 superimposed on the inner end surface of the pump casing portion 31, Thereby, the pump plate 32 and the pump housing portion 31 are fixed to each other with a plurality of bolts, whereby an oil pump chamber (not shown) is formed inside it, thereby, an internal gear (not shown) rotated by the crankshaft 7 and an internal gear placed therein The upper external gear can be installed in the oil pump chamber in a freely rotatable manner. The oil pump 29 communicates with the oil filter (not shown) in the oil pan 5 through the inflow passage 36, and communicates with the safety valve 42 and the high-pressure oil circuit 60, and the high-pressure oil circuit reaches the oil tank provided in the engine body through the discharge passage 37. individual sliding parts. The oil pump 29 sucks the oil in the oil pan 5 into the inflow passage 36, pressurizes the sucked oil, and discharges the oil into the discharge passage 37. At this time, the oil can be adjusted to the set pressure through the safety valve 42 . Excess oil returns to the sump.

The operation of the engine having the chain case 6 of the aforementioned structure will be described below.

When the engine 1 enters the driving state by turning on the ignition switch (not shown), the oil pump 29 is linked with the rotation of the crankshaft 7 and starts simultaneously, and the oil flows through the oil circulation system OS to make each sliding part and heated part in the engine body Receives flowing oil for lubrication and cooling. Simultaneously, the water pump 16 is activated to make the coolant flow through the coolant circulation system R. At this time, the engine is warming up and the temperature of the coolant is still low, and the thermostat 15 closes the cooling passage 22 so that the coolant returns to the pump chamber 161 without losing heat. When the engine has been fully warmed up and the temperature of the coolant increases to a higher temperature, the thermostat 15 opens the cooling passage 22, thereby allowing the coolant to flow from the outlet 19 to the radiator 14, where it loses its heat, Then return to the pump chamber 161.

In such an engine 1 , the pump chamber 161 in the form of a through hole is not provided in the cylinder block 2 but is provided in the thickened portion 28 on the chain case 6 . The pump chamber 161 thus provided is then closed with the pump cover 45 , thereby assembling the water pump 16 . Therefore, the pump chamber 161 can be formed in the aluminum alloy die-casting chain case 6 with good precision, so that it is not necessary to carry out cutting work (post-processing) necessary when the pump chamber is formed in the cylinder block after die-casting, so that the pump Chamber 161 can be made with great precision without the need for machining. Therefore, it is easy to ensure an appropriate clearance required when the impeller 43 is installed in the pump chamber 161, so that the cost can be reduced by simplifying the manufacturing process.

In addition, since only the pump chamber 161 in the form of a through hole is formed in the front wall 602 as an integral part of the water pump 16, the structure is simplified. In other words, in the process of die-casting the cylinder block 2 with the pump chamber, due to the structural complexity of the peripheral edge portion of the pump chamber, the cylinder block material at the peripheral edge of the pump chamber may cause shrinkage cavities, which is now dangerous. Therefore, the defective rate of the final cylinder block 2 can be reduced.

In addition, the end facing surface F of the cylinder block 2 and the oil/coolant boundary sealing surface on the side of the chain case 6 can be used as an oil sealing surface and a coolant sealing surface, thereby realizing the function of sealing both the oil and the coolant. Therefore, by making the coolant seal allowance and the oil seal allowance coincide with each other, the oil/coolant boundary seal surface fs can form a single seal strip, and therefore, the thickened portion 28 having the chain housing chamber 13 and the pump chamber 161 in the engine The amount of protrusion in the transverse direction Y can reduce this, which helps keep the dimensions of the engine as compact as possible.

In addition, since the thickened portion 28 doubles as the engine mount 49, the number of components can be reduced to such an extent, and since the engine mount 49 is a part of the thickened portion 28, the rigidity of the engine mount 49 becomes large, thereby maintaining sufficient strength and durability.

Although in the above embodiments, the thickened portion 28 doubles as the chain housing chamber 13, the pump chamber 161 of the water pump, the pump casing 31 of the oil pump 29, and the engine bracket 49, if necessary, the engine bracket 49 and the pump casing 31 of the oil pump 29 It can also be excluded to simplify its structure, in which case similar functions and advantages can still be obtained.

Although in the above embodiments, the engine 1 shown in FIG. 1 uses the oil pump 16 driven by the crankshaft 7, it may not be like this, and a structure in which an electric water pump (not shown) is arranged in the chain case 6 is adopted, In this case, similar functions and advantages to those obtained with the chain case 6 in FIG. 1 are still obtained.

While, in this embodiment, the engine chain case according to the present invention is described as being applied to an engine frame of a gasoline engine, the present invention can also be applied to a frame of a diesel engine.

second embodiment

An automotive four-stroke gasoline engine (hereinafter, simply referred to as engine 101 ) is shown in FIGS. 6 and 7 , to which the chain casing structure of the second embodiment of the present invention is applied.

In the engine 101, the cylinder head 103 and the cylinder head cover 104 are arranged on the upper side of the cylinder block 102, the oil pan 105 is arranged on the lower side of the cylinder block 102, and the chain case 106 is arranged on the side of the cylinder block 102 and one end of the cylinder head 103. The walls, whereby all these engine components are integrally interconnected to form the engine airframe. Furthermore, a plurality of cylinders S are arranged inside the cylinder block 102 and the cylinder head 103 . Intake and discharge of intake gas and exhaust gas drawn into and exhausted from a combustion chamber (not shown) located in the cylinder block S are controlled by components of the intake and exhaust system and the valve drive system or valve train, And the crankshaft 107 is driven to rotate upon receiving the output energy of the combustion chamber received by the piston (not shown).

A pair of intake and exhaust camshafts 108i, 108e (refer to FIGS. 7 and 10), which constitute a part of the valve train (not shown), are rotatably supported on the cylinder head 103 and The interior of the cylinder head cover 104 . Camshaft sprockets 109i, 109e (refer to FIG. 7) are integrally connected to the camshafts 108i, 108e, respectively. Specifically, the intake side camshaft sprocket 109i is connected to the intake camshaft 108i through the timer 111 (refer to FIG. 6 ), so that the timer 111, which receives the rotation of the crankshaft 107 through the chain 129 (refer to FIG. 7 ), The rotation of the crankshaft 107 is transmitted to an intake cam (not shown) after advancing or retarding the timing of valve opening and closing.

As shown in Figure 6, the cylinder block 102 is an aluminum alloy die-casting product, including a plurality of cylinders S and a cylinder side water jacket 116 for cooling around the plurality of cylinder blocks S, and the lower opening of the cylinder block 102 is closed with an oil pan 105 , thus forming the crankcase. The crankshaft 107 is arranged in the crankcase and is rotatably supported on a plurality of bearings (not shown), and a crankshaft sprocket 112, an internal gear (not shown) of an oil pump 113, and a crankshaft pulley 114 to be described later are integrally connected to one end of the crankshaft 107.

The cylinder head 103 is an aluminum alloy die-casting product, and the cylinder head 103 is formed with a cylinder head side water jacket 115 and an inner cavity 117. The main parts of the valve train VD, such as intake and exhaust camshafts 108i, 108e, are housed in the inner cavity 117 middle. As shown in FIG. 10 , an end inner wall 301 is formed at one end of the cylinder head 103, and extensions 302 protrude from the left and right ends of the end inner wall 301 to form extensions 302. On the connection flange 601, the flange portion of the extension 302 and the flange 601 of the chain case 6 are fastened together by bolts (not shown).

One end of the cylinder block 102 is formed with an end inner wall 118, and extensions 118g are formed protruding from the left and right ends of the end inner wall 118, and the flange portion at the end of the extension 118g is superimposed on the connecting flange 601 at the lower part of the chain case 106, The flange portion of the extension 118g and the flange 601 of the chain case 106 are fastened together by bolts (not shown). Note that, viewed from the top, the upper end inner wall 301 and the lower end inner wall 118 constitute the same cross-sectional shape and are integrally connected to each other. Here, the convex wall portion 121 extends in the transverse direction Y of the engine near the junction of the extension portion 118g of the cylinder block 102 and the rear outer wall 119 .

A flat end-facing surface F (part of the cylinder outer wall surface) is formed on the convex wall portion 121 toward one end of the cylinder block 102, and the same surface F is also formed to continue to the left and right extensions 118g. The case rear wall surface fc (refer to FIG. 8 ) of the chain case 106 is formed so as to be superimposed on the one end facing surface F thus formed.

As shown in FIGS. 6 and 8 , the chain case 106 is an aluminum die-casting piece, has a front wall 602 extending substantially continuously in the vertical direction and left and right connecting flanges 601, and thus has a concave cross-section viewed from the top, Thereby, when connected to the one end facing surface F, the central chain housing chamber 122 can be formed.

As shown in Figure 10, in the chain case 106, a through hole 123 (see Figure 8) through which the crankshaft 107 passes is formed in the lower part of its center, and a chain tensioner inspection hole 124 is formed in its upper part as a normally closed Opening, the inspection hole constitutes a part of the chain rotation transmission mechanism of the present invention. A main body 131 of a chain tensioner to be described below is mounted on the deeper side of the chain tensioner inspection hole 124 or on the end inner wall 118 of the cylinder block 102 at a position facing the chain tensioner inspection hole 124 . Here, the chain tensioner inspection hole 124 has an opening area to allow the main body 131 of the chain tensioner to be detached, and a normally closed cover 132 is overlaid on the opening around the edge portion of the inspection hole 124 so as to be normally closed. The chain tensioner inspection hole 124, so that the normally closed cover 132 can be bolted to the opening around the edge portion. Here, a normally closed cover 132 is fastened to the opening around the edge portion using a plurality of bolts in which threaded projections 133 (refer to FIGS. 6 to 8 ) formed with threaded holes are used. One bolt below the chain tensioner access hole 124 protrudes further into the chain receiving chamber 122 than the other threaded bosses. Also, the gap B formed between the threaded boss 133 and the inner wall surface of the right connecting flange 601 is set to be slightly smaller than the front and rear, left and right, And the outer width of the top and bottom sides, so that the threaded boss 133 and the right connecting flange 601 can function as a stopper, so that the chain tensioner main body 131 can be prevented from falling down.

The oil pump 113 for the oil circulation system OS is provided at the inner wall peripheral edge portion of the through hole 123 through which the crankshaft 107 passes, and a thickened portion 127 is continuously extended from the inner wall peripheral edge portion at a position facing the convex wall portion 121, and the water pump 126 is formed at the thickened portion.

As shown in Fig. 8, the oil pump 113 arranged at the center lower part of the front wall 602 includes a pump housing 146 and a pump disc 147, wherein the pump housing is formed by extending the periphery of the through hole 123 in the front wall 602 outward, and the pump disc stacks Placed on the inner end face of the pump casing 146 to be bolted thereto. In addition, an oil pump chamber (not shown) is formed inside the pump housing 146, and an internal gear (not shown) and an external gear are mounted in the oil pump chamber, wherein the internal gear is rotated by the crankshaft 107 and the external gear is mounted on the internal gear. The oil pump 113 communicates with an oil filter (not shown) in the oil pan through an inflow passage 148 , and communicates with a relief valve 1051 and various sliding parts provided in the engine body through a discharge passage 149 .

In the chain accommodating chamber 122, a chain support member 128 is provided in a protruding manner at the end of the pump housing 146, below the through hole 123. As shown in FIG. The chain support member 128 constitutes a deflection restricting member of an endless timing chain (hereinafter simply referred to as a chain 129 ), which constitutes a part of the main part of the chain type rotation transmission mechanism of the present invention. That is, the chain support member 128 functions to prevent the chain 129 from deflecting too much downward from the normal state in which the chain 129 extends around the crankshaft sprocket 112 in a normal manner. In a normal state, the chain support member 128 remains at a rest position p1, which is spaced by a predetermined gap from the crank sprocket 112 around which the chain 129 extends.

As shown in FIGS. 8 and 10 , a pump chamber 261 of the water pump 126 is defined on the thickened portion 127 of the chain case 106 . The water pump 126 includes a pump shaft 263, a pump cover 264 and a pump pulley 265. The pump shaft has a pump impeller 262 that is matingly inserted into the pump chamber 261. The pump cover rotatably fixes the pump shaft 263 and is fastened to On the front wall surface fd, the pump pulley is integrally connected to the protruding end of the pump shaft 263 . The pump chamber 261 communicates with the thermostat 136 on the cylinder block 102 side, and the discharge passage extending from the pump chamber 261 communicates with the discharge passage 137 on the cylinder block side. The block-side discharge passage 137 extends to the block-side water jacket 116 and the head-side water jacket 115 , the communication passage 138 in the cylinder head 103 , and the outlet 139 . When the engine is warming up and the temperature of the coolant is low, the outlet 139 is connected to the thermostat 136 through the short-circuit path 142. When the engine is fully warmed up and the temperature of the coolant has increased to a higher temperature, the outlet 139 passes Radiator 141 is connected to thermostat 136 .

In the chain case 6 of such an engine 101, the upper parts of the left and right side walls 601 are respectively integrally connected to the left and right extension parts 302 of the cylinder head cover 104, and the lower parts of the left and right side walls 601 are respectively integrally connected to the cylinder. The left and right extensions 118g of the body 102, whereby the chain accommodating chamber 122 is maintained in a tightly closed state and communicates with the upper and lower spaces of the oil pan 105 and the cylinder head cover 104, which facilitates the supply of oil to the chain 129. A chain 129 is accommodated in the chain housing chamber 122, wherein the chain 129 extends between the crank sprocket 112 and the intake and exhaust cams 109i, 109e. A chain tensioner including a chain tensioner main body 131 and a pair of chain guides 143 is arranged toward the chain 129 .

As shown in Figures 7 and 10, the pair of chain guides 143 are bolted to the end inner wall 130 of the cylinder head 103 and the end inner wall 118 of the cylinder block 102, and there is only one of the pair of guides 143 (the left side in Figure 7 The guide device) can pivot on the pivot support bolt 157 with its upper end as a fulcrum.

The chain tensioner main body 131 includes a plunger 155 , a spring 153 always supplying pressure to the plunger 155 , a hydraulic chamber 54 and a check valve 156 in a housing 134 bolted to the end inner wall 118 . The hydraulic chamber 54 is connected to the discharge passage 149 of the oil circulation system OS through a check valve 156, and the plunger 155 is extended to operate when the engine is driven by hydraulic pressure received therefrom. Here, a protrusion 1061 is integrally connected to the middle portion of one of the pair of guides 143 (the left guide in FIG. 7 ). Projection 1061 can be engaged with plunger 155, thereby exerts pressure on the chain guide 143 from plunger 155, when chain guide 143 pivots to move under this pressure, chain 129 is compressed, thereby automatically to Chain 129 provides tension. Note that an example of the main body of the hydraulic chain tensioner is also disclosed in JP-A-2002-156013.

The working process of the aforementioned engine having chain case structure will be described below.

When the engine 101 enters the driving state by turning on the ignition switch (not shown), the oil pump 129 is linked with the rotation of the crankshaft 107 and starts simultaneously, and the oil flows through the oil circulation system OS to make each sliding part and the heated part in the engine body Receives flowing oil for lubrication and cooling. At this time, the chain tensioner main body 131 receives the hydraulic pressure reaching the hydraulic pressure chamber 154 from the discharge passage 149 , and operates by extending the plunger 155 . The plunger 155 and one of the pair of chain guides 143 are then pivoted to apply an appropriate level of tension to the chain 129 . At this time, the tension of the chain 129 is changed to increase and decrease, and at the same time, the plunger 155 exerts a reaction force on the hydraulic pressure in the hydraulic chamber 154, and the check valve 156 prevents excessive oil from being discharged from the hydraulic chamber 154, thereby preventing Excessive deflection of the chain 129 prevents excessive noise. Note that the water pump 126 should also be started at the same time to circulate the coolant to cool the engine according to the engine cooling temperature.

Let us imagine that such an engine 101 is periodically inspected. At this time, remove the normally closed cover 132 from the chain case 106, and open the chain tensioner inspection hole 124 as a normally closed opening, so that the chain tensioner main body 131 can be removed from the chain through the chain tensioner inspection hole 124. The housing chamber 122 is removed to check the wear and/or damage of the various components in the chain tensioner main body 131, and then the chain tensioner main body 131 can be fixed to the end inner wall 118 side with bolts. In addition, let us assume that the operator accidentally drops the chain tensioner main body 131 during inspection or replacement work. In this case, the tensioner body 131 falls between the threaded boss 133 and the inner wall surface of the right connecting flange 601, both of which act as stops and are fixed in place . That is, the dropped distance can be controlled to a minimum, and the chain tensioner main body 131 locked on the side of the threaded boss 133 can be easily detached through the chain tensioner inspection hole 124 . Therefore, an extra work of opening the chain housing chamber 122 to take out the chain tensioner main body 131 dropped to the bottom of the chain housing chamber 122 by detaching the chain case 106 or the like can be dispensed with. Also, in the conventional inspection operation of only checking whether the chain tensioner main body 131 is normally applying pressure to the chain, the chain tensioner inspection hole 124 can be opened only by removing the normally closed cover 132, so that the chain tensioner inspection hole 124 can be opened in a very short time. Inspection operations can be easily completed within a short time.

In addition, here, since the threaded protrusion 133 formed on the inner wall of the chain case 106 doubles as a stopper, the number of parts and production cost can be reduced.

Note that the threaded bosses 133 may be arranged in plural to securely prevent the chain tensioner main body 131 from falling during its dismounting operation. In addition, a separate baffle plate (not shown) similar structure can also be arranged below the chain tensioner inspection hole 124, and be fixed on the inner wall of the chain case 106 with bolts, to further prevent the chain tensioner main body 131 from dropped during the disassembly operation.

Meanwhile, in the above-described embodiments, the chain case 106 shown in FIG. 6 is described as including the oil pump 113 and the water pump 261 integrally formed therewith. It is also possible to adopt another structure in which these parts are removed, and a chain tensioner inspection hole 24 is formed in the chain case. The structure of the chain case is simplified due to the removal of these constituent parts. In this case, it is still possible to obtain Similar functions and advantages are obtained by the chain case structure of the engine shown in FIG. 6 .

While, in the above embodiments, the chain case of the chain case structure according to the present invention is described as an aluminum die-casting, the present invention is equally applicable to the case where the chain case is an aluminum alloy die-casting.

Claims (7)

1. A chain case structure integrated with a water pump, comprising a chain case mounted on the end of the cylinder head (3) and having a housing chamber (13) for accommodating the rotating transmission mechanism arranged on the cylinder block (2) ( 6), and the water pump (16) installed in the chain case (6), the chain case integrated with the water pump is characterized in that it includes: a thickened portion (28), extending from part of the outer surface of the chain case (6), the wall thickness of which is thicker than that of the accommodation chamber (13); a through hole (161) formed in the thickened portion so as to be able to accommodate the impeller of the water pump penetrated therein; and The cover part (45) is used to close the through hole, thereby forming the vortex chamber of the water pump. 2. The chain case structure integrated with a water pump according to claim 1, characterized in that, the cover member (45) supports the impeller (43) of the water pump (16). 3. The chain case structure integrated with a water pump according to claim 1, characterized in that, the discharge passage recess (13) of the water pump (16) extends from the through hole to the thickened portion (28 ), so that the discharge passage recess (13) and the through hole can be sealed against the cylinder block (2) with a single seal (50). 4. The chain case structure integrated with a water pump according to claim 1, characterized in that, the bracket (49) for supporting the engine (1) is integrally arranged on the thickened part (28) to form the discharge Location of access recess (13). 5. The chain case structure integrated with a water pump according to claim 1, characterized in that, an opening (124) is formed at a predetermined position in the chain case, and the predetermined position faces to be accommodated in the chain case (6 ), the opening is used to remove the chain tensioner (131). 6. The chain housing structure integrated with a water pump according to claim 5, characterized in that a stopper (133) for preventing the chain tensioner (131) from falling is provided near the opening (124) , 601), the stopper protrudes from the outer wall surface of the chain case (6). 7. The chain casing structure integrated with a water pump according to claim 5, characterized in that, a normally closed cover (132) for closing the opening (124) is provided, and the stopper (133) is a machine Threaded projections for the machine screw used to fasten the normally closed cover (132) to the chain case (6).

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