JPS6341541Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention is a V-shaped structure in which camshaft pulleys are provided at the top of the left and right banks, and the camshaft pulleys are driven by a timing belt. This invention relates to an engine timing belt device.

(Prior art) In an overhead cam type V-type engine in which a camshaft pulley is provided at the top of the bank, the distance between the axes of both camshaft pulleys is long, so swinging of the timing belt between both camshaft pulleys is restricted. There is a need. For this reason, Utsukai 58-
As shown in Japanese Patent No. 9554, an idler was provided between both camshaft pulleys to adjust the tension of the timing belt and restrict its swing.

By the way, a water pump is usually placed at the joint between the left and right banks of a V-type engine, so
An idler cannot be attached to this part. Therefore, the idler is attached via a bracket to the intake manifold, etc. located in the space between the two banks, or the intake manifold, etc. is positioned above to form a gap for attaching the idler. However, it is desirable to have a structure as simple as possible so that the idler can be attached without increasing the overall height of the engine.

(Purpose of the invention) This invention was made in view of the above points, and it is possible to install an idler that regulates the runout of the timing belt between both camshaft pulleys with a simple and compact structure, and it is possible to install an idler that regulates the swing of the timing belt between both camshaft pulleys. The present invention provides a timing belt device for a V-type engine that can improve parallelism with a camshaft pulley.

(Structure of the invention) In this invention, a water pump is installed at the joint between the left and right banks on one end of the engine, and a camshaft pulley is installed in the cylinder head located at the top of both the left and right banks. Both camshaft pulleys are driven by a common timing belt at one end of the engine, and an idler for regulating the swinging of the timing belt is interposed between the two camshaft pulleys, and the idler is driven by a common timing belt on one end of the engine. In addition to being directly attached to the cylinder head, this idler and both camshaft pulleys are arranged on the same plane in the longitudinal direction of the engine, and the intake manifold etc. arranged in the space between the two banks The idler can be installed without changing the installation position.

(Example) FIG. 1 is a schematic diagram of a V-type engine in which a pair of left and right cylinder banks 1 and 2 are arranged in a V-shape. The cylinder banks 1 and 2 each include cylinder heads 3 and 4 and a cylinder block 5, and an intake manifold 6, a surge tank 7, a cooling water outlet passage 8, etc. are arranged in the space between the banks 1 and 2. ing. Further, a water pump 9 is provided projecting above the central portion of the cylinder block 5, that is, at the joint between the two banks 1 and 2. An oil pan 10 is located below the cylinder block 5.
A crankshaft 11 is provided in the crankcase formed by the oil pan 10 and the lower part of the cylinder block 5.

Camshafts 12 and 13 are provided above the cylinder banks 1 and 2, respectively, and camshaft pulleys 14 and 15 are fixed to the front ends of the camshafts 12 and 13 (see FIG. 2).
The camshaft pulleys 14 and 15 are connected to a crank pulley 16 fixed to the front end of the crankshaft 11 via a timing belt 17. Then, as the crank pulley 16 rotates in the direction of the arrow (clockwise), the camshaft pulley 1
4 and 15 are each rotated clockwise.

Tension pulleys 1 are disposed above the crank pulley 16 on the left and right sides and are in contact with the outer peripheral surface of the timing belt 17 to apply a predetermined tension to the timing belt 17.
8 and 19 are attached to the cylinder block 5. In addition, an idler 2 is attached to the cylinder head 3 of the left bank 1, which rolls in contact with the outer periphery of the timing belt and regulates the swinging of the timing belt 17.
0 is attached directly. That is, an idler mounting boss 21 is protruded from the front end surface of the cylinder head 3 shown in FIG.
3, the idler 20 is directly attached, and the idler 20 and the camshaft pulleys 14, 15 are disposed on the same plane in the longitudinal direction of the engine.

According to this configuration, since the idler 20 is directly attached to the cylinder head 3, the attachment position can be set more accurately than when it is fixed to the intake manifold 6 etc. via a bracket and indirectly attached to the engine body. At the same time, the parallelism with respect to the camshaft pulleys 14 and 15 is improved. In other words, the idler 20 and the camshaft pulleys 14, 15 can be accurately disposed on the same plane in the longitudinal direction of the engine. Also, cylinder head 3
Since there are no obstacles such as the water pump 9 on the front end surface of the idler 20, the idler 20 can be easily attached. Furthermore, since there is no need to shift the intake manifold 6, etc. upward between the left and right banks 1 and 2, unlike when providing a space for installing the idler 20 below the intake manifold 6, etc., the overall height of the engine can be reduced. This can prevent the engine from becoming larger.

Note that the idler 20 can be attached to the cylinder head 4 of the left and right banks 2, but in order to more reliably prevent the tooth skipping phenomenon of the timing belt 17, as shown in FIG. Install the idler 20 to the cylinder head 3 of
It is desirable to increase the winding angle of the belt 17 around the camshaft pulley 14 located on the slack side of the timing belt 17.

(Effects of the invention) As explained above, this invention, in an overhead cam type V-type engine, connects the camshaft pulleys provided on the cylinder heads located at the top of both the left and right banks on one end of the engine to a common engine. The idler, which is driven by a timing belt and regulates the runout of the timing belt, is directly attached to either the left or right cylinder head, so the idler can be mounted directly on either the left or right cylinder head without interfering with the water pump installed at the joint between the left and right banks. In addition, the overall height of the engine can be kept small and the engine can be made smaller. Moreover, since the idler and both camshaft pulleys can be precisely positioned on the same plane in the longitudinal direction of the engine, the parallelism between the idler and the camshaft pulley and the installation accuracy of the idler can be improved. This has the advantage that the longitudinal dimensions of the engine can be kept small.

[Brief explanation of the drawing]

Figure 1 is a front view showing an embodiment of this invention, Figure 2 is a front view showing an embodiment of this invention.
The figure is a sectional view taken along the line -- in FIG. 1. 1, 2... Cylinder bank, 3, 4... Cylinder head, 9... Water pump, 14, 15...
...Camshaft pulley, 17...Timing belt, 20...Idler.

Claims (1)

[Scope of utility model registration request] A water pump is installed at the joint between the left and right banks on one end of the engine, and a camshaft pulley is installed on the cylinder head located at the top of both the left and right banks. An idler that is driven by a common timing belt and that regulates the swinging of this timing belt is interposed between the two camshaft pulleys, and the idler is directly attached to the cylinder head of either the left or right bank. A timing belt device for a V-type engine, characterized in that an idler and both camshaft pulleys are arranged on the same plane in the longitudinal direction of the engine.