JP2755981B2 - V-type engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an overhead cam type V which transmits a rotation of a crankshaft to a camshaft after being reduced on an intermediate shaft.
Related to shaped engines.

[Related Art] Recently, there has been a demand for an engine for a passenger car to reduce the engine length and the engine width as much as possible due to the restriction of the size of an engine room. For this reason, in a so-called DOHC type V-type engine in which a pair of cylinders are arranged in a V-shape and two camshafts for intake and exhaust are provided in the cylinder head of each cylinder, these two types are used. It is desired to make the cylinder head as small as possible by minimizing the arrangement interval of the camshafts.

For this reason, conventionally, as seen in, for example, JP-A-59-74312, an intermediate shaft is provided between the camshaft and the crankshaft of each cylinder, and the deceleration provided on the intermediate shaft is provided. There is known a V-type engine in which a pulley and a crankshaft are linked via a single common timing belt, and a drive sprocket on the intermediate shaft and a camshaft are linked via a timing chain. .

According to the V-type engine, the rotational speed of the crankshaft is transmitted to the camshaft after being once reduced, so that the diameter of the timing sprocket on the camshaft can be reduced. Therefore, the interval between the two camshafts can be reduced to reduce the size of the cylinder head, which is advantageous in suppressing the engine width to be narrow.

[Problems to be Solved by the Invention] In this type of V-type engine, a water pump for circulating engine cooling water is usually provided in a V-shaped space formed by a pair of cylinders in order to simplify the flow path of engine cooling water. Has been arranged. In this case, in the V-type engine having the camshaft driving means as described above, the rotation of the crankshaft is transmitted to the intermediate shaft of each cylinder by one timing belt. There is a possibility that the wrapped portion extending between the intermediate shafts protrudes into the space and interferes with the water pump. For this reason, in order to prevent interference between the water pump and the timing belt, the water pump is displaced toward the cylinder head side, or the timing belt is placed between the intermediate shafts of the cylinders as seen in the prior art. It is necessary to provide a guide roller that presses downward and make the running line of the timing belt largely curved downward, so as to secure a space for disposing the water pump.

However, when the water pump is displaced, the water pump greatly protrudes above the cylinder, so that the overall height of the engine is increased, and when the running line of the timing belt is corrected downward, the timing belt is greatly bent. This is undesirable in terms of durability.

The present invention has been made in view of such circumstances, and can prevent the water pump from interfering with the primary winding transmission body, and can install the water pump at a low position between the cylinders. It is an object of the present invention to provide a V-type engine which is capable of improving the durability of a primary winding transmission and allowing a water pump and a cooling water inlet to be close to each other, and which is compact as a whole.

Means for Solving the Problems In order to achieve the above object, the present invention provides a cylinder block having a pair of cylinders arranged in a V-shape. The cylinder head is provided with a cam shaft for valve operation, and the cylinder block is provided with a pair of intermediate shafts located between the cam shaft and the crank shaft of each of the cylinders. A single primary winding transmission is passed between the toothed wheel and the crankshaft, and between each of the camshafts and another toothed wheel that rotates integrally with the toothed wheel. A secondary winding transmission is passed over, the rotation of the crankshaft is reduced on the central axis, and then transmitted to the camshaft. On the other hand, in a V-shaped space sandwiched by the pair of cylinders,
It is assumed that the engine is a V-type engine in which a water pump for circulating engine cooling water is arranged.

In the primary winding transmission, the running path of the winding portion extending between the intermediate shafts is substantially linear, and the water pump is disposed above the winding portion, and the water pump is disposed between the cylinders. At the bottom of the space, one main passage for distributing engine cooling water to the water jacket of each cylinder is formed, and the cooling water inlet of this main passage is between the pair of intermediate shafts and the crankshaft. By setting it right above, it is installed in a portion surrounded by the traveling path of the primary winding transmission, and discharges between the cooling water inlet and the water pump across the winding portion of the primary winding transmission. It is characterized by being connected via a passage.

[Operation] According to this configuration, the cooling water inlet of the main passage is disposed in a portion surrounded by the traveling path of the primary winding transmission,
Moreover, since the discharge passage connecting the cooling water inlet and the water pump straddles the winding portion of the primary winding transmission, the position of the water pump can be lowered without being restricted by the primary winding transmission, Interference between the water pump and the primary winding transmission can also be prevented.

At the same time, since the cooling water inlet is located in a portion surrounded by the traveling path of the primary winding transmission, the cooling water inlet is substantially linear over a pair of intermediate shafts of the primary winding transmission. The water pump is opposed to the water pump with the wrap-shaped portion interposed therebetween. Therefore, the water pump and the cooling water inlet have a positional relationship such that they are adjacent to each other, so that the entire length of the discharge passage can be shortened and the shape thereof can be simplified. Therefore, the portion from the cooling water inlet to the water pump is compactly combined, and the position of the water pump can be lowered, and the entire engine can be formed compact.

In addition, since the primary winding transmission is stretched in a substantially straight line between the pair of intermediate shafts, the traveling path is smooth with less bending, and the primary winding transmission is correspondingly durable. The performance is improved.

Embodiment An embodiment of the present invention will be described below with reference to the drawings applied to a water-cooled V-type six-cylinder engine.

The cylinder block denoted by reference numeral 1 in the drawing is a lower case 2
And a pair of cylinders 3a and 3b erected in a V-shape on the upper surface of the lower case 2. The cylinders 3a and 3b include a cylinder row 5 having three cylinders 4 arranged side by side.
And the cylinder row 5 is integrated with the lower case 2.

One crankshaft 7 is accommodated in the lower case 2 along the direction in which the cylinders 4 are arranged. The crankshaft 7 is supported by a bearing wall 8 provided on the lower case 2 via a bearing cap 9, and the six crankpins 7 a provided on the crankshaft 7 are provided with cylinders 4 facing the V-shape. Are connected alternately via connecting rods.
Therefore, the pair of cylinders 3a and 3b are offset in the axial direction of the crankshaft 7.

The cylinder head 6 of each of the cylinders 3a and 3b is provided with an intake camshaft 10 and an exhaust camshaft 11. Each of the camshafts 10 and 11 has a cam 14 for opening and closing the intake valve 12 and the exhaust valve 13, and a timing sprocket 15 is attached to one end of each of the camshafts 10 and 11.

In the figure, reference numeral 16 denotes an intake camshaft 10 and an exhaust camshaft 11.
It is a head cover that covers the periphery of.

As shown in FIGS. 2 and 3, one end of the crankshaft 7 is led out of the lower case 2 and a case cover 17 that covers the front surface of the lower case 2. An oil pump 18 of the shape is provided. The pump body 19 of the oil pump 18 is supported by the case cover 17 and the oil pan 20, and the inner rotor 21 is mounted on the crankshaft 7 passing through the pump body 19.
Has been fixed. Also, lower case 2 and case cover
17, intermediate shafts 26a and 26b are supported by bearings 25 for each of the cylinders 3a and 3b. Intermediate shafts 26a and 26b are cam shafts
A first intermediate sprocket 27, which constitutes a speed reduction toothed wheel, is fixed between the crankshaft 7 and the crankshaft 7. This first intermediate sprocket
The number of teeth of the first intermediate sprocket 27 is larger than the number of teeth of the drive tooth portion 28 provided on the crankshaft 7.
A single primary timing chain 29 that forms a primary winding transmission is bridged between the driving tooth portion 28 and the driving tooth portion 28. The primary timing chain 29 is extended in a substantially inverted triangular shape when the cylinder block 1 is viewed from the front side along the axial direction of the crankshaft 7, and the primary timing chain 29 is provided on one of the cylinders 3a side. Tension wound around the crankshaft 7 from the first intermediate sprocket 27
29a is guided by a chain guide 33, and a slack portion 29b fed from the crankshaft 7 to the first intermediate sprocket 27 on the other cylinder 3b side is pressed by a tensioner 34. For this reason, in the case of the present embodiment, the winding portion 30 that straddles between the first intermediate sprockets 27 in the primary timing chain 29 is bridged without slack along the horizontal direction, and its traveling route is It is straight without bending. Note that the winding portion 30 does not necessarily need to be stretched in a straight line, and for example, a chain guide that contacts the winding portion 30 is provided on the running line, and the running line of the winding portion 30 is formed into an arc shape close to a straight line. It may be curved. In short, it is good if the winding portion 30 does not sharply bend.

Further, a second intermediate sprocket 31 constituting another toothed wheel is integrally formed on the outer periphery of the intermediate shafts 26a and 26b, adjacent to the first intermediate sprocket 27. The number of teeth of the second intermediate sprocket 31 is smaller than the number of teeth of the first intermediate sprocket 27, the driving teeth 28 and the timing sprocket 15, and the number of teeth between the second intermediate sprocket 31 and the timing sprocket 15 is smaller. And a multi-row secondary timing chain 32 constituting a secondary winding transmission. Therefore, the rotation speed of the crankshaft 7 is
This crankshaft 7 and intermediate shafts 26a, 26b and intermediate shafts 26a, 26b
After being decelerated over two stages between and the camshafts 10 and 11,
The power is transmitted to the camshafts 10 and 11.

The second intermediate sprocket 31 on the intermediate shafts 26a, 26b
As shown in FIG. 3, the secondary timing chain 32 is shifted in the axial direction by an amount corresponding to the offset amount of the cylinders 3a, 3b, and when the engine is viewed from the side, the two cylinders 3a, 3b The primary timing chain 29 is located between the secondary timing chains 32 of FIG.

Incidentally, the pair of cylinders 3a, 3b form a V-shaped space 35 between the opposing side walls, and a main passage 36 for the cooling water is formed in the upper part of the lower case 2, which is the bottom of the space 35. And The main passage 36 extends in the axial direction of the crankshaft 7 and communicates with the water jackets 37 of the respective cylinders 4 through distribution ports 38.
, And constitutes a cooling water inlet 39. The cooling water inlet 39 of the main passage 36 is connected to the pair of intermediate shafts 26a, 26
b and just above the crankshaft 7. That is, as shown in FIG. 1 and FIG. 2, the cooling water inlet 39 is a traveling path of the primary timing chain 29 stretched in an inverted triangular shape, that is, the tension portion 29a and the slack portion 29b of the primary timing chain 29. And a portion surrounded by the winding portion 30, and is located just below the winding portion 30 of the primary timing chain 29. For this reason, the wrap portion 30 crosses the front side of the bottom of the space 35 in the horizontal direction.

Immediately above the leading end of the crankshaft 7, a water pump 40 for pumping engine cooling water to the main passage 36 is provided.
Is arranged. The water pump 40 has a space 3 between the cylinders 3a and 3b when the cylinder block 1 is viewed from the front side.
5 is located within the primary timing chain 29
Is located above the wrapping portion 30. Water pump
Forty pump bodies 41 are bolted to the front surface of the lower case 2, and a pump cover 42 covering the front surface of the pump body 41 supports a pump shaft 44 for driving an impeller 43. A driven pulley is located at the outside end of the pump shaft 44.
A V-belt is provided between the driven pulley 45 and a driving pulley 46 attached to the leading end of the crankshaft 7.
47 are wound. The pump body 41 has a cooling water suction port 48 connected to a bypass passage and a pipe from a radiator (not shown), and a cooling water discharge passage formed at a joint portion between the pump body 41 and the pump cover 42. 49 are provided. The discharge passage 49 extends downward in front of the winding portion 30 of the primary timing chain 29, and has a lower end bent toward the case cover 17 to form a communication passage provided in the case cover 17. It is connected to the cooling water inlet 39 of the main passage 36 via 50. Therefore, the discharge passage 49 is connected to the primary timing chain.
The water pump 40 straddles 29 winding portions 30 and connects a cooling water inlet 39 which is distributed up and down with the winding portions 30 interposed therebetween.

According to such a configuration, the primary timing chain for driving the first intermediate sprocket 27 on the intermediate shafts 26a and 26b
The first intermediate sprocket 27 is installed linearly without slack between the first intermediate sprockets 27. A cooling water inlet 39 connected to the main passage 36 is arranged below the winding portion 30 of the primary timing chain 29, and The water pump 40 is disposed above the hanging portion 30, and the water pump 40 and the cooling water inlet 39 are connected by the discharge passage 49 straddling the winding portion 30, so that the winding portion of the primary timing chain 29 Space 35 only for cooling water inlet 39 located below 30
The mounting position of the water pump 40 in the inside can be lowered.

At the same time, the discharge passage 49 of the water pump 40 straddles the travel path of the primary timing chain 29,
The primary timing chain 29, the water pump 40, and the discharge passage 49 do not interfere with each other, and there is no need to displace the water pump 40 upward.

In addition, according to the above configuration, the cooling water inlet 39 and the water pump 40 are connected to the winding portion 30 of the primary timing chain 29.
, The cooling water inlet 39 and the water pump 40 are positioned adjacent to each other at the bottom of the space 35 between the cylinders 3a and 3b. Therefore, the entire length of the discharge passage 49 can be shortened, and the shape of the discharge passage 49 can be simplified in combination with the single cooling water inlet 39. The configuration of the passage does not need to be complicated.

Therefore, in combination with the fact that the position of the water pump 40 can be lowered, it is possible to keep both the engine width and the engine height small, and the whole engine can be made compact.

In addition, since the primary timing chain 29 is linearly installed between the first intermediate sprockets 27, the traveling path thereof is smooth with little bending. Therefore, there is an advantage that the bending load applied to the primary timing chain 29 is reduced and the durability is improved.

In the above embodiment, the rotation speed of the crankshaft is transmitted to the intermediate shaft and the camshaft via the chain, but a toothed belt may be used instead of the chain.

Further, the V-type engine according to the present invention is not limited to a six-cylinder engine,
It may be a V-type four cylinder or eight cylinder.

[Effects of the Invention] According to the present invention described in detail above, the cooling water inlet is disposed in a portion surrounded by the traveling path of the primary winding transmission, and the discharge passage connecting the cooling water inlet and the water pump. Straddles the winding portion of the primary winding transmission, the position of the water pump can be lowered while preventing interference between the water pump and the primary winding transmission. In addition, the cooling water inlet and the water pump face each other across the winding portion, and the cooling water inlet and the water pump have a positional relationship such that they are adjacent to each other at the bottom of the space between the cylinders. Can be shortened, and the shape of the discharge passage can be simplified, so that the passage configuration for guiding the engine cooling water to the cooling water inlet does not have to be complicated. Therefore, in addition to the fact that the position of the water pump can be lowered, it is possible to keep both the engine width and height small, which contributes to downsizing of the entire engine.

In addition, the running path of the primary wrapping transmission is also smooth with little bending, and the bending load applied to the primary wrapping transmission is reduced by that amount, and the durability is improved.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a front view partially showing a positional relationship of a water pump and a drive system of a cam shaft. FIG. 2 is a sectional view taken along line II-II in FIG. FIG. 3 is a cross-sectional view of the drive system path of the camshaft, and FIG. 4 is a front view of the V-shaped engine partially cut. 1 ... Cylinder block, 3a, 3b ... Cylinder, 6 ...
Cylinder head, 7 ... Crank shaft, 10, 11 ... Cam shaft (intake cam shaft, exhaust cam shaft), 26a, 26b ... Intermediate shaft, 27,31 ... Toothed wheel (first intermediate sprocket , Second intermediate sprocket), 29 primary winding transmission (primary timing chain), 30 winding part, 32
… Secondary winding transmission (secondary timing chain), 35
…… Space, 36 …… Main passage, 37 …… Water jacket,
39: Cooling water inlet, 40: Water pump, 49: Discharge passage.

Claims (1)

(57) [Claims] 1. A cylinder block comprising a pair of cylinders arranged in a V-shape, a cylinder shaft having one crankshaft, and a cylinder head of each cylinder having a camshaft for a valve train. The cylinder block is provided with a pair of intermediate shafts located between the camshaft and the crankshaft of each of the cylinders, and one between the crankshaft and the toothed wheel for deceleration provided on these intermediate shafts. Along with the common primary winding transmission, the secondary winding transmissions are respectively extended between the other toothed wheels that rotate integrally with the toothed wheel and each camshaft,
After reducing the rotation of the crankshaft on the central axis and transmitting the rotation to the camshaft, a V-shaped engine in which a water pump for circulating engine cooling water is arranged in a V-shaped space sandwiched by the pair of cylinders, Of the primary winding transmission, the running path of the winding portion extending between the intermediate shafts is substantially linear, and the water pump is disposed above the winding portion, and the space between the cylinders is At the bottom, one main passage for distributing engine cooling water to the water jacket of each cylinder is formed, and the cooling water inlet of this main passage is between the pair of intermediate shafts and directly above the crankshaft. The primary winding transmission is installed in a portion surrounded by the traveling path of the primary winding transmission, and the primary winding transmission is wound between the cooling water inlet and the water pump. V-shaped engine, characterized in that connected through the discharge passage across the.