JPH0732911Y2 - Engine end structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of Invention] <Industrial Application Field> The present invention is directed to a crankshaft through a winding transmission mechanism in order to cancel the pitching vibration of the engine by rotating in the opposite direction of the crankshaft. And an end structure of an engine having a balancer shaft connected to the.

<Prior art> In an in-line odd-cylinder engine, the pistons located at each end of the crankshaft reciprocate with different phase relationships, which causes pitching vibration due to the primary inertia couple in the axial direction of the crankshaft. To do. As a means for removing this vibration, it is well known to use a counterweight provided on the crank web and a balancer shaft that rotates in the opposite direction of the crankshaft and at the same rotational speed (Japanese Patent Laid-Open No. Sho. 62-188835).
Then, the publication discloses a structure in which a crank shaft and a balancer shaft are interlockingly driven via a winding transmission mechanism such as a timing belt and a timing pulley.

<Problems to be solved by the invention> By the way, in this type of wrapping transmission mechanism, a predetermined wrapping angle with respect to the pulley or sprocket is required in terms of driving torque transmission efficiency. Therefore, in general, the desired winding angle is set by defining the direction of the belt or chain by using an idler pulley or idler sprocket (see Japanese Patent Laid-Open No. 61-104114).

Bending stress due to belt tension acts on the support shaft of the idler pulley, but this stress tends to increase as the engine speed increases. Therefore, when the support rigidity of the idler pulley is insufficient, the belt tension becomes unstable and the belt vibrates. Therefore,
The axial rigidity of the idler pulley is preferably as high as possible.

On the other hand, depending on the layout, the support portion of the idler pulley may be provided in the housing of the lubricating oil pump joined to the end surface of the cylinder block. In this case, since the support rigidity of the idler pulley depends on the rigidity of the pump housing, it is desired that the rigidity of the pump housing be as high as possible.

The present invention has been devised to address such a problem, and provides an end structure of an engine capable of easily increasing the support strength of an idler pulley without relatively increasing the manufacturing cost. To provide.

[Structure of the Invention] <Means for Solving the Problem> According to the present invention, the purpose is to synchronize the camshaft with the crankshaft protruding from the housing of the lubricating oil pump joined to the end surface of the cylinder block. A first winding transmission mechanism for rotating, a second winding transmission mechanism for synchronously rotating the accessory with respect to the crankshaft, and a second winding transmission mechanism on the accessory side of the second winding transmission mechanism. An end structure of an engine having an idler wheel that defines a winding angle with respect to a transmission wheel, wherein a boss for holding a base portion of a support shaft of the idler wheel is projectingly provided on the lubricating oil pump housing. A first rib for connecting between an outer peripheral surface of the outer peripheral surface of the lubricating oil pump housing and an outer surface of the lubricating oil pump housing in a direction substantially along a direction in which a pressure contact force of the second winding transmission mechanism with respect to the idler wheel acts. A second rib that connects the outer peripheral surface of the boss and the outer surface of the lubricating oil pump housing in a direction orthogonal to the first rib, and the transmission wheel on the accessory side, the idler wheel, and the Provided is an end structure for an engine, wherein all of the first and second ribs are arranged between a contour line of the cylinder block and an outer peripheral surface of a track of the first winding transmission mechanism. It is achieved by

<Operation> In this way, rigidity is imparted to the attachment base portion of the idler wheel in a direction that counteracts the pressure contact force with respect to the idler wheel due to the tension of the winding transmission belt such as a belt. Moreover, by providing the two ribs in directions orthogonal to each other,
High rigidity is secured in all rotation directions of the idler vehicle itself, and stress distribution is optimized. Further, by disposing all of the accessory transmission wheel, the idler wheel, and the first and second ribs between the contour line of the cylinder block and the outer peripheral surface of the winding transmission band of the first winding transmission mechanism, The size of the block in the width direction is reduced, and the first and second ribs do not have to interfere with the track of the first winding transmission mechanism.

<Embodiment> A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in FIG. 1, an engine 1 constructed according to the present invention has a cylinder block 2 similar to a general engine.
It has a crank pulley 4 fixed to the shaft end of a crank shaft 3 protruding from one end face in the cylinder row direction. The crank pulley 4 can wind a plurality of timing belts arranged side by side in the axial direction, and can rotate integrally with the crankshaft 3.

Between the one timing pulley groove and the cam pulley 7 fixed to the shaft end of the cam shaft 6 provided on the cylinder head 5, the cam shaft 6 is synchronously rotated with respect to the crank shaft 3. The timing belt 8 is wound, and the balancer shaft 9 which is one of the auxiliary machines arranged on one side portion (left side in FIG. 1) of the cylinder block 2 is installed in the other timing pulley groove. A timing belt 11 is wound around a balancer pulley 10 provided on the balancer shaft 9 for driving in conjunction with the motor 3. In this way, the crank pulley 4, the cam pulley 7, and the timing belt 8 constitute a first winding transmission mechanism,
The crank pulley 4, the balancer pulley 10, and the timing belt 11 constitute a second winding transmission mechanism.

A timing belt 8 for driving the cam shaft 6 is wound around a pump pulley 12 of a cooling water circulation pump provided on the right side portion of the cylinder block 2, and a winding angle with respect to the pump pulley 12 is set to a predetermined value and a predetermined value. In order to apply the belt tension of the timing belt 8 to the timing belt 8, a tension pulley 13 is provided at the center of the cylinder block 2 to apply a pressure contact force to the back surface of the timing belt 8.

The timing belt 11 for driving the crankshaft 3 and the balancer shaft 9 in an interlocking manner has teeth on both sides thereof, and a predetermined tension is applied by a tension pulley 14 provided in a direction away from the crankshaft 3. The teeth are provided and mesh with the balancer pulley 10 by the teeth on the back side thereof. An idler pulley 15 is provided at an intermediate portion between the crank pulley 4 and the balancer pulley 10 in order to set the wrapping angle of the timing belt 11 around the balancer pulley 10 to a predetermined value.

In this way, the balancer shaft 9 rotates clockwise as the crank shaft 3 rotates counterclockwise as viewed from the crank pulley 4 side. Also,
The balancer pulley 10, the tension pulley 14, and the idler pulley 15 are axially supported by the end surface of the cylinder block 2 along the extending direction of the cylinder block 2 at positions close to the timing belt 8. The width dimension is made compact.

In addition, on the right side surface of the cylinder block 2, an alternator
16 is provided, which is linked to the crankshaft 3 by another V pulley and V belt (not shown).

Between each pulley and the end wall of the cylinder block 2,
The housing 17 of the lubricating oil pump is fixed.

FIG. 2 shows the lubricating oil pump housing 17 as a single unit. This pump housing 17 has a crankshaft 3 at the center.
A hole 18 through which the pump main body is inserted is provided, and a pump chamber for accommodating a pump main body, which is directly connected to a crank shaft made of a known trochoid pump, is formed on the back surface of the hole. A hole 19 for inserting the shaft end of the balancer shaft 9 is opened in the upper left side, and a boss 20 for fixing the rotating shaft of the idler pulley 15 is provided below the hole 19 and to the left of the crank shaft inserting hole 18.
Is projected. The boss 20 is provided with two ribs 21a and 21b in a direction substantially orthogonal to each other in the radial direction.

Now, bending stress due to belt tension acts on the support shaft of the idler pulley 15. In particular, as shown in the above examples,
When the housing 17 of the lubricating oil pump joined to the end surface of the cylinder block 2 is provided with the support portion of the idler pulley 15, the pump housing 17 is made of a plate-shaped member. This leads to insufficient support rigidity of the pulley 15. Therefore, in the present invention, the boss 20 for mounting the idler pulley 15
Further, the rigidity of the base end portion of the boss 20 is enhanced by providing the first rib 21a along the pressing direction (arrow A in FIG. 2) due to the tension of the timing belt 11 acting on the idler pulley 15. .

Since the metal material generally has a relatively high tensile strength, it is preferable that the rib is provided radially outside with respect to the pressure contact force of the timing belt 11. Further, by disposing the second rib 21b in the direction orthogonal to the first rib 21a, it is possible to deal with the stress center deviation in accordance with the rotation direction of the idler pulley 15 and to disperse the stress. Further, since the first and second ribs 21a and 21b are both arranged at positions where they do not interfere with the timing belt 8 that drives the cam shaft 6, the design of the transmission mechanism of the cam shaft 6 is not affected.

[Advantage of the Invention] As described above, according to the present invention, it becomes possible to effectively increase the support rigidity of the pivot base end portion of the idler pulley without increasing the thickness of the pump housing itself, and to vibrate the idler pulley itself. It can be hard to do. Therefore, the operation of the accessory drive belt is stabilized, and a great effect can be achieved in promoting the reduction of vibration of the engine. In addition to this, the accessory pulley, the idler pulley, and the two ribs can all be arranged inside the contour line of the cylinder block, so that the dimension of the cylinder block in the width direction can be reduced, and both ribs can be cranked together. Since it does not interfere with the orbit of the timing belt wound between the pulley and the cam pulley, the degree of freedom in designing the first winding transmission mechanism is increased.

[Brief description of drawings]

1 is an elevation view of a pulley side of an engine constructed according to the present invention, and FIG. 2 is an enlarged view of a lubricating oil pump housing. 1 ... Engine, 2 ... Cylinder block 3 ... Crank shaft, 4 ... Crank pulley 5 ... Cylinder head, 6 ... Cam shaft 7 ... Cam pulley, 8 ... Timing belt 9 ... Balancer shaft, 10 ... Balancer pulley 11 Timing belt 12 Pump pulley 13 14 Tension pulley 15 Idler pulley 16 Alternator 17 Pump housing 18 19 Holes 20 Boss 21a 21b rib

Claims (1)

[Scope of utility model registration request] 1. A first winding transmission mechanism for synchronously rotating a cam shaft with respect to a crank shaft projecting from a housing of a lubricating oil pump joined to an end surface of a cylinder block, and an auxiliary machine for the crank shaft. And an idler wheel for defining a winding angle of the second winding transmission mechanism with respect to the transmission wheel on the supplementary side of the second winding transmission mechanism for synchronously rotating the two. A second boss for fixing the base portion of the support shaft of the idler wheel to the lubricating oil pump housing so as to project from the outer peripheral surface of the boss to an outer surface of the lubricating oil pump housing; First ribs that are connected in a direction substantially along the direction in which the pressure contact force of the winding transmission mechanism acts, and the outer peripheral surface of the boss and the lubricating oil pump housing in a direction orthogonal to the first ribs. Provided with a second rib for connecting between the outer surface of ring, the accessory side of the transmission wheel, the idler wheel, and the first
-The end structure of the engine, wherein all of the second ribs are arranged between the contour line of the cylinder block and the outer peripheral surface of the track of the first winding transmission mechanism.