JPH03286149A - Auxiliary machine installation structure for dohc engine - Google Patents

Abstract

PURPOSE:To prevent the transmission of the vibration in the engine operation to an auxiliary machine through buffering by supporting the auxiliary machine connected with a camshaft from below in the projection state exceeding the upper edge part of a belt cover, by the belt cover through a sealing member. CONSTITUTION:A crank angle detecting sensor 17 and a cylinder judging sensor 18 as auxiliary machine are supported through a sealing member 16a from underside by a belt cover 15. Accordingly, the vibration of an engine 1 is buffered by a sealing member 16, and the transmission of the vibration to the auxiliaries 17 and 18 is prevented. Accordingly, the generation of chattering in the connection part between the shafts on the auxiliary 17, 18 sides and camshafts 4 and 5 is suppressed, and the bad influence to the auxiliaries 17 and 18 can be suppressed. Further, since the auxiliaries 17 and 18 are supported by the belt cover 15, the supporting force for the auxiliaries 17 and 18 is increased, and even if the relatively large-sized auxiliaries 17 and 18 are installed in projection outside, exceeding over the belt cover 15, the lack of strength is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an accessory mounting structure in a DOHC engine in which a camshaft provided in a cylinder head is driven by the rotational force of a crankshaft.

(Prior Art) In DOHC (overhead camshaft) engines for automobiles, the opening and closing operations of the intake valve and exhaust valve of each cylinder are controlled by a pair of camshafts disposed directly above the cylinder head. In this case, for example, as disclosed in Japanese Utility Model Application Publication No. 61-1977231,
The camshaft on the intake side and the camshaft on the exhaust side are linked by camshaft gears attached to each camshaft, and of both camshafts,
By applying rotational force from the crankshaft to one camshaft to rotate the camshaft, and at the same time transmitting the rotational force of this camshaft to the other camshaft via the above gear, both camshafts are rotated synchronously. What is done is done.

The above publication also states that in a V-type DOHC engine,
The cylinders in the first bank and the cylinders in the second bank are arranged at different positions in the axial direction of the crankshaft, and a space is formed in front of the first bank and in the rear of the second bank. Taking advantage of this, a technology has been disclosed in which the camshaft gears of each bank are arranged in these spaces, and an auxiliary drive unit that is linked to the rotation of one of the camshaft gears is provided in the space of the first bank. has been done.

According to this, the above-mentioned bank space can be used effectively, the engine can be made more compact, and the auxiliary equipment can be driven using the rotational force of the camshaft.

(Problem to be Solved by the Invention) By the way, in an engine having banks in parallel like the above V-type DOHC engine, one of the camshafts and crankshafts in each bank is attached to these shafts. The rotational force of the engine is transmitted to the camshafts of each bank by interlocking a rotational force transmission mechanism consisting of pulleys (cam boolean and crank pulley) and a belt wrapped around these pulleys. In this case, the rotational force transmission mechanism is usually covered with a belt cover to prevent dust.

Therefore, if the auxiliary equipment attached to the camshaft is relatively large, such as a crank angle detection sensor or a cylinder discrimination sensor, the problem of interference with the belt cover will occur.

To solve this problem, it is conceivable to arrange the above-mentioned auxiliary machine outside the belt cover and connect the auxiliary machine and the camshaft with a small-diameter joint that does not interfere with the belt cover. However, in such a configuration, a large auxiliary machine is cantilever-supported by a long joint, which causes strength problems, and also causes the auxiliary machine to shake due to engine vibration, which has an adverse effect on the auxiliary machine. In particular, there is a high possibility that the above-mentioned vibration will cause looseness in the connection between the shaft on the auxiliary side and the camshaft, and the detection accuracy of the above-mentioned crank angle detection sensor and cylinder discrimination sensor will decrease, impairing their reliability. It turns out.

SUMMARY OF THE INVENTION An object of the present invention is to provide a mounting structure for attaching an auxiliary machine to a camshaft, in which engine vibrations do not affect the auxiliary machine.

(Means for Solving the Problems) That is, in the present invention, a cylinder head is provided with a pair of camshafts that open and close intake and exhaust valves, respectively, a cam pulley attached to one of these camshafts, and a crankshaft attached to a pair of camshafts. A DOHC in which the attached crank pulley is interlocked by a belt, the one camshaft is interlocked with the other camshaft via a rotational force transmission means, and the boob and belt are sealed by a belt cover. In the engine, an accessory driven by the shaft is attached to one end of the other camshaft so as to protrude beyond the upper edge of the belt cover, and the lower surface of the accessory is attached to the peripheral edge of the belt cover. It is characterized in that the cover is brought into contact with the upper edge of the cover via a sealing material attached to the cover.

(Function) According to the above configuration, since the auxiliary equipment is supported from below by the belt cover and via the sealing material, engine vibrations are buffered by the sealing material and are less likely to reach the auxiliary equipment. Therefore, the occurrence of play in the connection between the shaft and the camshaft on the auxiliary equipment side is suppressed, and adverse effects on the auxiliary equipment, such as the crank angle detection sensor and the cylinder discrimination sensor, can be avoided.

In addition, since the auxiliary equipment is supported by the belt cover, the supporting force of the auxiliary equipment increases, so even if a relatively large auxiliary equipment is installed so as to protrude outward beyond the top of the belt cover, the auxiliary equipment is not strong enough. There will be no shortage.

(Example) Next, embodiments of the present invention will be described based on the drawings.

Figure 1 shows type D to which the auxiliary equipment mounting structure according to the present invention is applied.
This shows an OHC engine 1, which has a pair of banks 2A and 2B in parallel, and the cylinder head 3 (shown in FIG. 2) of each bank 2A and 2B has an intake valve and an exhaust valve for each cylinder to open and close. A pair of camshafts 4 to operate
．． 5 are arranged respectively. And each bank 2A,
2B, camshaft gears 6.7 are fixed to the shaft ends of the pair of camshafts 4.5, and these gears 6.7 are meshed with each other, so that both camshafts 4.5 are interlocked. There is.

Also, one end of the pair of camshafts 4.5 in each bank 2A, 2B projects outward from the cylinder head 3, and a cam pulley 8 is attached to the projecting end of one camshaft 4 in each bank 2A, 2B. .9 is installed. A crank pulley 11 is attached to the crankshaft 10 of the engine 1 corresponding to these cam pulleys 8.8.
is attached, and the timing belt 1 extends across three pulleys, the cam pulley 8.9 and the crank pulley 11.
2 is wrapped around. As a result, the rotational force of the engine 1 is input to one camshaft 4 in each bank 2B via the crank pulley 11, belt 12, and cam pulley 8.9, and the camshaft 4 is rotationally driven. Further, the other camshaft 5, which is interlocked with the camshaft 4 by the aforementioned gear 6.7, is simultaneously rotated.

Idle pulleys 13 to 13 are pressed against the belt 12, and a tension pulley 14 applies an appropriate tension. And pulley 8.9.11
．． The entire rotational force transmission mechanism consisting of belts 13 and 14 and the belt 12 is sealed by a belt cover 15 to prevent dust.

In that case, a sealing material 16 is disposed and attached to the side edge of the belt cover 15 over almost the entire area of the side edge of the cover as shown by the broken line in FIG. The belt cover 15 is sealed by bringing it into contact with the cylinder block side.

Furthermore, the cam pulley 8.9 of each bank 2A, 2B
An auxiliary machine is attached to the protruding end of the camshaft 5 on the other side to which the camshaft 5 is not attached. That is, the first bank 2
On the A side, a crank angle detection sensor 17 is installed for use when starting the engine 1 and for backup purposes, and on the second bank 2B side, a cylinder discrimination sensor 18 is installed. These sensors 17 and 18 are attached to the head cover 15 as shown in FIGS. 2 and 3.
are located outside the cover beyond the upper part of the cover, and in this state are respectively connected to the camshaft 5.

Next, the auxiliary equipment mounting structure will be described in detail, taking as an example the case of the crank angle detection sensor 17 on the first bank 2A side. The auxiliary equipment mounting structure described below is the same for the cylinder discrimination sensor 18 described above.

That is, at the end of the camshaft 5 on which the auxiliary equipment is attached, the cylinder head 3 and the bearing are supported by the cover 19, and the cover 19 is connected to the bolt 20.2.
0 to the cylinder head 3. In this bearing, a cylindrical socket member 22 is attached to the portion 21 coaxially and from the outside, and a bolt 23
．． 23, the socket member 22 is connected to the cylinder head 3.
And the bearing is fixed to the cover 19.

This socket member 22 has a length such that its tip protrudes outward beyond the top of the belt cover 15 in the above-mentioned installed state, and a sensor fixing arm 24 is provided protruding from the outer surface of the tip side. . The use of this socket member 22 is necessary because the crank angle detection sensor 17 (or cylinder discrimination sensor 18) attached to the camshaft 5 is structurally large because it has a relatively large-diameter rotating disk inside. This is because it is necessary to arrange it outside the belt cover 15 in order to avoid interference with the belt cover 15.

On the other hand, the crank angle detection sensor 17 has a connecting plate 25 protrudingly provided at a suitable position on the circumferential surface of its main body in correspondence with the aforementioned sensor fixing arm 24 of the socket member 22, and a connection plate 25 is provided in a protruding manner at a suitable position on the circumferential surface of the main body. A boss portion 26 with a diameter that is large enough to fit is integrally provided, and a sensor rotation shaft 28 connected to a rotating disk 27 (shown in FIGS. 7 and 8) inside the main body is attached to the boss portion 26. inserted and supported. The tip of the rotating shaft 28 is connected to the boss portion 2 as shown in FIG.
6 Exposed outside. Then, the crank angle detection sensor 17 is attached by inserting the boss portion 26 into the socket member 22, and in this state, the sensor rotation shaft 28 is fitted into the end of the camshaft 5 inserted into the bearing portion 21 with a concave-convex fit. They are connected by a joint structure. Therefore, when the camshaft 5 rotates, the rotating disk 27 within the sensor 17 also rotates due to its rotational force.

In addition, when the crank angle detection sensor 17 is inserted into the socket member 22, the connecting plate 25 is attached to the sensor fixing arm 24 on the socket member side using a fastener 32 such as a bolt or a nut.
are connected and fixed in place.

By the way, the belt cover 15 abuts the circumferential surface of the socket member 22 via a sealing material at the portion that passes under the crank angle detection sensor 17 (the same applies to the cylinder discrimination sensor), and the socket member 22 and The structure is such that the sensor 17 inserted into the member 22 is supported from below.

That is, the belt cover 15 is shaped to cover the cam pulley 8 on the first bank 2A side, but the upper edge of the belt cover 15 in that part passes under the socket 22 and reaches the second bank 2B side. It becomes. In that case, as shown in FIG. 2, the cover 15 is attached to the socket member 22 through the sealing material 16a attached to the cover in the arc range R shown in FIG. 22 to support the socket member 22 from below.

In addition, at both end portions R1 and R2 (shown in FIG. 4) of the arcuate range R supporting the socket member 22, the belt cover 15 is attached in the longitudinal direction of the socket member 22 (that is, the camshaft 5 and the sensor rotation axis) as shown in FIG. 28) over a predetermined length L via the sealing material 16a, and thereby the socket member 22 is also supported by the cover 15 on the side surface of the socket continuous to the arcuate range R.

Moreover, with the above-mentioned socket member support structure, the space between the belt cover 15 and the socket member 22 is sealed by the sealing material 16a, and dustproofing inside the cover can be ensured satisfactorily.

According to the above configuration, the crank angle detection sensor 17 attached to the socket member 22 is located outside the belt cover 15 and is cantilever-supported on the cylinder head 3 side via the socket member 22. However, since the belt cover 15 supports the socket member 22 from below,
The sensor supporting force of the socket member 22 is increased, and even if the sensor 17 is arranged to protrude outward beyond the belt cover 15, there is no need to worry about the strength of the sensor 17 in its supported state.

Moreover, the vibration caused by the rotation of the engine 1 is caused by the socket member 22.
and the belt cover 15.
Since it is buffered by a, the influence on the socket member 22 is reduced, and the vibration of the sensor 17 is also suppressed. Therefore, no load is placed on the joint between the sensor rotating shaft 28 and the camshaft 5 inside the socket member 22, and the joint does not become loose, thereby increasing the detection accuracy and reliability of the sensor 17. Become.

Note that the above operation is similar on the cylinder discrimination sensor 18 side.

In addition, the belt cover 15 of the embodiment shown in FIG.
As is clear from the drawing, there are three covers 15a, 1
5b and 15c are assembled and used by joining them at the joining portion shown by arrow B. That is, the belt cover 15 is composed of three integrated covers 15a, 15b, and 15c. In this case, in this embodiment, the cover integral joint parts B, B are placed directly under the crank angle detection sensor 17 and the cylinder detection sensor 18, and the cover integral joint parts B, B are used to perform the operation as described above. Each sensor is mounted so that a partial socket member 22 is supported within the arcuate range R.

According to this configuration, as shown in FIG. 6, in the joint portion B, there is a joint structure in which one cover unit 15a is stacked with the other cover unit 15b with the sealing material 16b sandwiched therebetween. As a result of this, the rigidity of the joint A is increased, so that the -layer socket member 22 and the sensor 17,18
This increases the supporting force of the sensors 17 and 18, contributing to stable support of the sensors 17 and 18.

By the way, in FIG. 1, the crank angle detection sensor 17 is installed on the first bank 2A side, and the cylinder discrimination sensor 18 is installed on the second bank 2B side. These sensors 17 and 18 detect the camshaft 5 when the engine is rotating.
The rotational force is input through the sensor rotation shaft 28, and the rotation disk 27 rotates. As shown in FIG. 7, this rotating disk 27 has an appropriate number of through holes 29 according to each sensor function.
...29 are opened at predetermined intervals in the circumferential direction, and as the disk rotates, the sensor head moves through the through holes 29...29.
By identifying this, the sensor 17 on the first bank 2A side detects the crank angle, and the sensor 17 on the second bank 2B side detects the crank angle.
At step 8, cylinder discrimination is performed.

However, in the sensors that utilize the through holes 29 as described above, by changing the size of the through holes, it is also possible to provide the above two functions to a single sensor. In other words, for cylinder identification, the through holes 29...29 are equal to the number of cylinders.
is required as shown in Figure 7, and one of the through holes 2
The shape of 9a is enlarged in the disk radial direction, and the cylinder discrimination sensor head 30 that identifies the large through hole 29a and the crank angle detection sensor head 31 that identifies the small through holes 29...29 are shown in the disk radial direction. If the structure is such that the sensor heads 30 and 31 are arranged at different positions, the respective sensor heads 30 and 31 are arranged through the corresponding through-holes 29...2 as the disk rotates.
In identifying 9.29a, two functions are obtained. If such a sensor is used, only one bank needs to be equipped with a sensor.

(Effects of the Invention) As is clear from the above description, the present invention provides an arrangement in which an auxiliary machine connected to a camshaft protrudes beyond the upper edge of a belt cover, and a sealing material is attached to the belt cover from below. Since vibrations during engine operation are damped by the sealing material and are less likely to reach the auxiliary equipment, rattling of the connection between the auxiliary equipment shaft and the camshaft is suppressed, and for example, the vibration of the crankshaft is suppressed. Adverse effects on auxiliary devices such as angle detection sensors and cylinder discrimination sensors are avoided, and the detection accuracy and reliability of the auxiliary devices are improved.

In addition, since the auxiliary equipment is supported by the belt cover and the supporting force of the auxiliary equipment is increased, even if a relatively large auxiliary equipment is installed so as to protrude outward beyond the belt cover, the auxiliary equipment will not be affected. There is no shortage of support strength, so stable support is possible.

[Brief explanation of drawings]

The drawings show an embodiment of the auxiliary equipment mounting structure for a DOHC engine according to the present invention, and FIG. 1 is a front view of the DOHC engine;
Fig. 2 is a plan view taken along the line U-II in Fig. 1, and Fig. 3 is a plan view of the
Figure 4 is a cross-sectional view taken along the line ■-■ of the figure, IV-IV of Figure 3.
Fig. 5 is an enlarged view of the part indicated by arrow A in Fig. 3, Fig. 6 is an enlarged sectional view taken from the line Vl-Vl in Fig. 4, and Fig. 7 is the sensor. Figure 8 is the internal front view of Figure 4.
It is a cutaway view taken along the line. 1...Engine, 3...Cylinder head, 4.5...
・Camshaft, 6, 7... Rotational force transmission means (camshaft gear), 8.9... Cam pulley, 10... Crankshaft, 11... Crank pulley, 12...
- Belt, 15...Belt cover, 16a...Sealing material, 17.18...Auxiliary equipment (17 is a crank angle detection sensor, 18 is a cylinder discrimination sensor).

Claims (1)

[Claims] (1) The cylinder head is equipped with a pair of camshafts that open and close the intake and exhaust valves, and the cam pulley attached to one of these camshafts and the crank pulley attached to the crankshaft are linked by a belt. , and in a DOHC engine in which the one camshaft is interlocked with the other camshaft via a rotational force transmission means, and the pulley and belt are sealed by a belt cover, at one end of the other camshaft, An auxiliary machine driven by the shaft is installed in a state that protrudes beyond the upper edge of the belt cover, and the bottom surface of the auxiliary machine is connected to the cover through a sealing material attached to the peripheral edge of the belt cover. DOH characterized by being brought into contact with the upper edge of the
C engine auxiliary equipment mounting structure.