JPH0521625Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an engine timing belt chamber ventilation system.

(Prior art) Generally, in engines that use a toothed timing belt to drive a camshaft from the crankshaft, a timing belt cover is installed on the front housing of the engine body in order to protect the timing belt from dust, water, and foreign objects. is fixed to form a timing belt chamber, but this timing belt chamber has poor ventilation and reaches high temperatures, which often has a negative effect on the durability of the timing belt.
As disclosed in Publication No. 180018, at least one of the pulleys arranged in the timing belt chamber is provided with the function of a fan, and an air inlet and an air exhaust are provided in the timing belt cover forming the timing belt chamber. Timing belt room ventilation devices are known which are provided with an outlet.

However, in the above-mentioned conventional type, the timing belt can ventilate the room by providing a fan function, but the air flow formed by the fan causes turbulence inside the timing belt room. As a result, cooling performance may be reduced.

(Purpose of the invention) In the present invention, a timing belt cover is fixed to the front housing of the engine body to form a timing belt chamber, and a cam pulley attached to the tip of a camshaft passing through the front housing is wound around the cam pulley. The cam pulley is disposed in the timing belt chamber in such a manner that it is pulled downward by the timing belt, the cam pulley has a function as a fan, and the timing belt cover is located at a position facing the cam pulley having the function as a fan. In a configuration in which an air inlet is provided in the chamber and an air outlet is provided at a position below the air inlet, the timing belt is cooled by smoothing the flow of air within the timing belt chamber. It is an object of the present invention to provide a timing belt chamber cooling device that improves the strength of a front housing.

(Structure of the Invention) In the engine timing belt chamber cooling device according to the present invention, the shaft cylinder part that pivotally supports the tip of the camshaft having the cam pulley having the function of the fan attached to the front housing is located on the side of the timing belt cover. A rib extends from the shaft cylinder portion to the surface of the front housing, and extends in a direction that substantially coincides with the tension direction of the timing belt and the flow direction of the air from the air inlet to the air outlet. It is characterized in that it is provided with a

(Effects of the invention) According to the invention, the flow of air introduced from the air inlet by the fan is guided by the ribs and flows uniformly toward the air outlet, improving ventilation capacity and timing. The cooling effect of the belt can be enhanced. Additionally, when the tip of the camshaft tries to move downward due to the tension of the timing belt acting on the cam pulley, a downward force acts on the shaft cylinder that supports the tip of the camshaft. According to the present invention, since the rib extends from the shaft cylinder part to the surface of the housing along the tension direction of the timing belt, the shaft cylinder part is supported by the rib and the shaft cylinder part is prevented from falling. can do.

(Example) An example of the present invention will be described in detail below with reference to the drawings.

Fig. 1 is a front view showing the entire engine timing belt chamber ventilation system according to the present invention with its timing belt cover removed, and Fig. 2 is a longitudinal sectional view of the entire system, which is installed at the front end of the engine body 1. A crankshaft 3 and a camshaft 4 protrude through the front housing 2, and a timing belt 7 is wound between a crank pulley 5 and a cam pulley 6, which are attached to the tips of the shafts 3 and 4, respectively. It is adapted to receive a force pulled downward by the timing belt 7. Further, an idler 8 and a pulley 9 for driving a water pump are provided in the middle of the timing belt 7, and an appropriate tension is further applied by a tensioner 10.

The timing belt cover 11 attached to the front housing 2 is divided into upper and lower parts, and is divided into an upper belt cover 12 and a lower belt cover 13.
The lower belt cover lower 13 is provided to cover only the upper part from the center of the crank pulley 5, and the lower part of the crank pulley 5 is covered by a flange 15 formed on the oil pump case 14. It is being said. This flange 15
As is clear from FIG. 2, the upper surface of the front end thereof is inclined downwardly toward the front, thereby promoting the fall of water and facilitating removal from the mold during die-casting. A timing belt chamber 16 is formed by the front housing 2 and the belt cover 11.
In order to ventilate the cam pulley 6, a fan 17 separate from the cam pulley 6 is coaxially attached to the front end of the cam pulley 6. The fan 17 is fixed to the camshaft 4 together with the cam pulley 6 by bolts 18.

As shown in FIGS. 3 and 4, the fan 17 is made of a press-molded iron plate, and in the valley between the plurality of (eight in the figure) fan blades 17a,
A positioning pawl 18 is provided by bending the fan 17 from the mounting surface thereof at a substantially right angle toward the back side (the cam pulley 6 side). As shown in FIGS. 5 and 6, the cam pulley 6 has a front end periphery of a center boss portion 6c that connects a rim portion 6a having teeth on the outer periphery with a plurality of (eight) spoke portions 6b. An engaging groove 19 into which the pawl 18 of the fan 17 can fit is formed in the portion, and the combination of the pawl 18 and the engaging groove 19 facilitates alignment and angle alignment of the fan 17 with respect to the cam pulley 6. be able to. Furthermore, when the fan 17 is manufactured by press forming an iron plate as shown in FIGS. 3 and 4, it is necessary to form a kerf at the base of the fan blade 17a in order to give the fan blade 17a a twist. However, by bending the pawl 18, it is possible to prevent breakage in the valley between the fan blades 17a during press forming. Therefore, the fan 17 can be easily manufactured by one press molding.

On the other hand, an air inlet for the timing belt chamber 16 is formed in the belt cover upper 12 of the timing belt cover 11 in front of the fan 17. As can be seen, the belt cover upper 12 is made up of a number of circular holes 21. In order to prevent dust from entering the timing belt chamber 16, these holes 21 are covered with an air filter member 22 made of nonwoven fabric and disposed on the front surface of the belt cover upper 12. In order to hold this air filter member 22, the ninth
A holding member 23 made of a circular frame as shown in the figure is welded to the front surface of the belt cover upper 12. The detailed structure around the hole 21 as an air inlet is shown in the enlarged sectional view of FIG.
A projecting edge 24 is formed on the peripheral edge of the first air filter member 22 side (front side). Providing this ridge 24 improves the rigidity of the belt cover upper 12, and water that enters from the outside and is absorbed by the air filter falls downward along the outer periphery of the ridge 24, so the timing belt room 16
It is possible to prevent water from entering inside. A chamfered portion 24a is formed on the inner periphery of the projecting edge 24 to improve the effect of suppressing water intrusion.

Further, on the back side of the belt cover upper 12, an annular rib 25 having a diameter approximately equal to the rim diameter of the cam pulley 6 is provided on the rim portion 6a of the cam pulley 6.
It is formed so as to be close to the side surface of the By providing this rib 25, the air sucked by the fan 17 efficiently flows into the timing belt chamber 16, and prevents the intake air from flowing back through the gap between the fan 17 and the belt cover upper 12. This rib can also be 25
This also helps improve the rigidity of the belt cover upper 12. Therefore, the amount of deformation of the belt cover upper 12 toward the fan 17 due to the negative pressure generated by the fan 17 is reduced;
Since the belt cover upper 12 is prevented from being further deformed by contacting the side surface of the belt cover a, damage to the fan 17 due to the contact of the belt cover upper 12 can be prevented.

The air introduced from the air inlet configured as described above flows downward within the timing belt chamber 16, cools the timing belt 7, and is discharged from the air outlet provided at the lower part of the belt cover lower 13. However, the front housing 2 is provided with means for smoothing this air flow and improving the cooling performance of the timing belt. That is, as shown in FIGS. 2 and 11, the tip portion of the camshaft 4 is provided in alignment with the bearing portion 26 of the camshaft 4 and protrudes forward from the front housing 2, that is, toward the belt cover upper 12 side. A rib 28 is formed on the front surface of the front housing 2 and extends from the shaft cylindrical portion 27 that supports the front housing 2 downward toward the air outlet. This rib 28 extends from the shaft cylinder portion 27 to the surface of the front housing 2 in a direction that substantially matches the tension direction of the timing belt 7 and the flow direction of the wind from the air inlet to the air outlet. In addition to having a function as a rectifying means, the rib 28 also serves to reinforce the portion 2a of the front housing 2 that serves as the wall on the front side of the water jacket 29 of the engine body 1, and also serves to strengthen the shaft cylinder due to the tensile force of the timing belt 7. Part 27
11, the central rib 28 also has the function of preventing the water jacket 29 from falling downward. For this reason, as is clear from FIG.
It is provided approximately in the center of a.

One embodiment of the present invention has been clarified from the above description. According to the above embodiment, the front housing 2 is provided with the rib 28 extending from the shaft cylinder portion 27 toward the air exhaust port, so that the fan 17 uniformly flows toward the air outlet along the ribs 28, the ventilation capacity is improved and the cooling effect of the timing belt 7 can be enhanced. Further, the strength of the front housing 2 can be improved by the ribs 28, and the front housing 2 can be firmly fixed to the water jacket 29, thereby eliminating leakage of cooling water and improving sealing performance.

In addition, in the above-mentioned embodiment, the fan 17 is provided separately from the cam pulley 6, but instead of this,
By configuring the spoke portions 6b of the cam pulley 6 in the shape of a fan blade, the cam pulley 6 itself can have a function as a fan.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a front view of the entire engine timing belt chamber ventilation system with the timing belt cover removed; FIG. 2 is a longitudinal sectional view of the entire system; Figure 3 is a rear view of the fan, Figure 4 is a side view of the fan, Figure 5 is a front view of the cam pulley, Figure 6 is a sectional view taken along the - line in Figure 5, and Figure 7 is the air inlet. 8 is a front view showing the upper part of the belt cover upper, FIG. 9 is a front view of the air filter holding member, FIG. 10 is an enlarged sectional view of the main part of the air inlet, and FIG. 11 is a front view showing the upper part of the belt cover upper. is a front view of the front housing. 1...Engine body, 2...Front housing, 3...Crankshaft, 4...Camshaft, 5...Crank pulley, 6...Cam pulley,
6a...Rim part, 6b...Spoke part, 6c...
Center boss section, 7...Timing belt, 11
...Timing belt cover, 12...Timing belt upper, 13...Belt cover lower, 16...Timing belt chamber, 17...Fan, 17a...Fan blade, 18...Positioning pawl, 19...In charge Matching groove, 21... Hole, 22...
...Air filter member, 23...Holding member, 24...
...projection, 25...rib, 27...shaft cylinder part, 28...
...Rib, 29...Water jacket.

Claims (1)

[Claim for Utility Model Registration] A timing belt cover is fixed to the front housing of the engine body to form a timing belt chamber, and a cam pulley attached to the tip of a camshaft passing through the front housing is wound around the cam pulley. The cam pulley is disposed in the timing belt chamber so as to be pulled downward by a timing belt, and the cam pulley has a function as a fan, and is located on the timing belt cover at a position opposite to the cam pulley having the function as a fan. In the timing belt chamber ventilation system for an engine, the engine timing belt chamber ventilation device is provided with an air inlet and an air outlet is provided at a position below the air inlet, wherein the front housing includes a cam pulley having a function as the fan. A shaft cylinder part that pivotally supports the tip of the camshaft with the attached camshaft is provided so as to protrude toward the timing belt cover side, and extends in the tension direction of the timing belt and in the flow direction of the air from the air inlet to the air outlet. A timing belt chamber ventilation device for an engine, characterized in that ribs extending in substantially coincident directions are provided from the shaft cylinder portion to the surface of the front housing.