JPH04128522A - Rotation sensor installation structure of engine - Google Patents

Abstract

PURPOSE:To simply and correctly detect rotation of an engine by arranging an idler rotating synchronously with a cam pulley in front of a cam shaft and installing a rotation sensor to detect rotation of a detection element provided on this idler on the inside of an engine cover. CONSTITUTION:A rotational force of a timing pulley 37 fixed on a crank shaft is transmitted to a cam pulley 22 and an idle pulley 30 through a timing belt 34. And rotation of the cam pulley 22 is transmitted to a suction side cam shaft 11 through a phase adjustment device 20 and accordingly, an exhaust side cam shaft 12 is interlocked. And in company with rotation of the idle pulley 30, each of shielding plates 31, 32 fixed on the idle pulley 30 integrally rotates in one body, and accordingly, light radiated from radiative elements 451, 461 to light reception elements 452, 462 is intermittently shielded in each of rotation sensors 45, 46. Consequently, a pulse signal is output from each of the rotation sensors 45, 46, and accordingly, discrimination of a cylinder is carried out simultaneously when rotation position of the idle pulley 30 is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a mounting structure for a rotation sensor for detecting engine rotation speed and the like.

[Conventional technology]

Conventionally, some of the engines installed in automobiles etc., as shown in Japanese Utility Model Application No. 62-1.84149, for example,
There is one in which a timing pulley attached to a crankshaft and a cam pulley are connected by a timing belt, and the timing belt is covered from the front with a head cover.

In such an engine, if a distributor or a rotation sensor such as a crank angle sensor is installed on the front side of the engine, the presence of the distributor on the front side makes it difficult to route the belt, and the sealing performance of the belt cover may be affected. Because of this, distributors and the like are generally installed on the rear side of the engine.

[Problem to be solved by the invention]

In recent years, for DOHC engines, for example,
As shown in Japanese Patent No. 0008, both camshafts are interlocked via gears, etc., and a cam pulley is attached to only one camshaft via a phase adjustment device at its front end. It has become known to be possible to control the opening and closing timing of a valve by changing the phase difference using the phase adjustment device (see Utility Model Application Publication No. 62-69005, etc.).

In such an engine, if a rotation sensor such as a distributor or a crank angle sensor is installed on the rear side as described above, this rotation sensor will detect rotation corresponding to the rotation of the camshaft, so the phase adjustment described above will be performed. When the adjustment operation of the device is performed, there is an inconvenience that an error occurs between the rotation state of the cam pulley corresponding to the actual Kuraray angle and the rotation detection result.

In view of these circumstances, the present invention enables accurate rotation detection without causing any error even when the phase difference is adjusted between the cam pulley and the camshaft. The purpose of the present invention is to provide a structure in which a rotation sensor can be mounted compactly without impairing sealing performance.

[Means to solve the problem]

The present invention provides an engine in which an intake side camshaft and an exhaust side camshaft are driven in conjunction with each other, and a phase adjustment device is provided for adjusting the phase difference between one camshaft and a cam pulley attached to the other camshaft. An idler is rotatably disposed in front of the shaft, and configured to rotate in synchronization with the cam pulley. A detector is provided on the idler, and the detector is mounted on the inner surface of the engine cover that covers the idler. A rotation sensor for detecting rotation is attached (claim 1).

Furthermore, it is more effective if a positioning member is provided protrudingly on the inner surface of the engine cover to which the rotation sensor is attached, and an inserted part into which the positioning member is inserted is provided in the support part of the idler. 2).

[Function] First, according to the structure according to claim 1, the rotation of the idler that rotates in synchronization with the camboo J is detected by the detector and the co-rotation sensor, so that the rotation of the cam pulley is directly detected. Even if the phase difference between the camshaft and the camshaft changes, the detection results are not directly affected. Further, since the detector and the rotation sensor are housed within the engine cover, the sealing performance of the engine cover is not impaired by their attachment.

Furthermore, according to the structure according to claim 2, the positioning member protruding from the engine cover side is inserted into the inserted part provided on the side of the idler support part, so that the engine cover is moved relative to the idler support part. Positioning, i.e.
The relative positions of the detector attached to the idler and the rotation sensor are surely aligned.

〔Example〕

FIG. 1 is a cross-sectional plan view of an engine in one embodiment of the present invention. In the engine block 10 shown here, an intake camshaft 1 and an exhaust camshaft 12, which extend in the longitudinal direction of the engine (vertical direction in the figure), are rotatably supported. Each camshaft 11.12
A cam 13.14 is formed in the cam shaft 13.14, and a sprocket 15.16 is fixed at an appropriate position, and both sprockets 15.16 are connected by a chain 18, and both camshafts 1.1.12 are connected to each other. They are designed to rotate together.

A cam pulley 22 is attached to the front end of the intake side cam shirt 1 via a phase adjustment device 20 having an internal structure (not shown). The phase adjustment device 1I20 is for appropriately shifting the phase difference between the intake side camshaft 11 and the cam pulley 22, thereby adjusting the valve opening/closing timing to an appropriate timing.
Various types commonly used in engines, such as the one shown in Japanese Patent No. 9005, are applicable.

A front end portion of the exhaust side camshaft 12 projects forward from the front end surface of the engine block 10, and this projecting portion is covered by an idler support member 24.

The idler support member 24 has a plate-shaped main body 241 , and the main body 241 is fixed to the front end surface of the engine block 10 with bolts 25 . This main body part 24
An idler support portion 242 is provided protruding from the center of the front side of 1, and a cylindrical fitting portion 243 is provided protruding from the center of the back side.

This fitting portion 243 is the engine block]
In this state, the fitting portion 243 and the center portion of the main body portion 241 form a space 26 in which the front end portion of the camshaft 11 is accommodated. .

An idler pulley (idler) 30 is rotatably mounted on the outer periphery of the idler support portion 242 via a bearing 28. On the front side of the idle pulley 30, there are two ring-shaped shielding plates (detectors) 31.
32 is fixed at a position coaxial with the idler support section 242. Each shielding plate 31, 32 is provided with a number of openings (not shown) in the circumferential direction. Further, the intervals between the openings in the shielding plate 32 are set to be different for each cylinder.

On the other hand, in the lower part of this engine, a timing pulley 37 as shown in FIG. 2 is fixed to the front end of the crankshaft. is passed, and appropriate tension is applied to this timing belt 34 by tension pulleys 35 and 36.

This timing pulley 34 is covered with engine covers 38 and 39 placed in front of the engine, and a disc-shaped cover 40 is also provided at a position corresponding to the idle pulley 30.
are arranged. This cup (-40) has a positioning part 41 protruding from its back side, and this positioning part 41 is fitted into a positioning hole 244 provided at the center of the idler support part 242 in the idler support member 24. By doing so, the idle pulley 30 and cover 4
The relative positions of the 0's are matched. Then, in this positioned state, the peripheral edge of the cover 40 is fixed to the other covers 38 and 39 with bolts 42 shown in FIG.

Two rotation sensors 45.4 are provided on the inner surface of this cover 40.
6 is installed. These rotation sensors 45. ．． 4
6 is composed of a transmission type optical switch, and the rotation sensor 45 includes a light emitting element 451 and a light receiving element 452.
are provided at positions that sandwich the opening provided in the shielding plate 31 from both sides, and the rotation sensor 46 is provided at a position where its light emitting element 461 and light receiving element 462 sandwich the opening provided in the shielding plate 32 from both sides. ing.

Next, the operation of this engine will be explained.

In FIG. 2, the rotational force of a timing pulley 37 fixed to the crankshaft is transmitted to the cam pulley 22 and idler pulley 30 via the timing belt 34, so that both pulleys 22 and 30 are always interlocked with a constant phase difference. Driven.

The rotation of the cam pulley 22 is transmitted to the intake side camshaft 13 via the phase adjustment device 20, whereby both camshafts 11, 12 are driven in conjunction.

On the other hand, as the idle pulley 30 rotates, two shielding plates 31. ．． 32 rotate together, the light emitting element 4 in each rotation sensor 45, 46
5], 46], the light irradiated onto the light receiving elements 452 and 462 is intermittently blocked. As a result, each rotation sensor 45, 46 outputs a pulse signal, and the rotation sensor 4
The rotational position of the idle pulley 30 is detected by the pulse signal from the rotation sensor 46, and the cylinder is determined by the pulse signal from the rotation sensor 46.

Therefore, according to this structure, the rotation of the cam pulley 22 and the timing pulley 37 can be accurately detected by first detecting the rotation of the idle pulley 30, which is always interlocked with the cam pulley 22.

However, even if the phase difference between the cam pulley 22 and the camshaft 1 is adjusted by the operation of the phase adjustment device 20, the phase difference between the cam pulley 22 and the idle pulley 30 does not change, so the above-mentioned adjustment is performed as in the conventional device. The operation of the phase adjustment device 20 does not affect the rotation detection results.

Further, shielding plates 31 and 32 as detectors are provided on the side of the idle pulley 30, and a rotation sensor 4 for detecting the rotation thereof.
5.46 is attached to the back surface of the cover 40, the entire rotation sensor is housed within the cover, the structure is compact, and the sealing performance of the engine covers 38 to 40 is not impaired.

Further, in the structure of this embodiment, the positioning portion 4 provided on the cover 40 side, and the idler support member 24
The relative positions of the shielding plates 31, 32, which are the detectors, and the rotation sensors 45, 46 are reliably determined, and accurate rotation detection is possible. Guaranteed.

Furthermore, since the idler support member 24 is also used as a cover for the camshaft 12, it is possible to prevent lubricating oil from leaking from the shaft with a more compact structure, and the fitting portion 244 of the idler support member 24 serves as a rib. By supporting the idler pulley 30, the supporting rigidity of the idler pulley 30 can be increased.

In this embodiment, the cam pulley 22 is attached to the intake camshaft 11, but the present invention can achieve similar effects even when a cam pulley is attached to the exhaust camshaft.

Furthermore, in the present invention, regardless of the specific structure of the rotation sensor,
The same effect as above can be obtained by using a light reflection type sensor, a magnetic sensor, or the like.

[Effects of the Invention] As described above, the present invention arranges an idler that rotates in synchronization with the cam pulley in front of the camshaft on the side where the cam pulley is not attached, and detects the rotation of a detector provided on this idler. Since the rotation sensor is attached to the inner surface of the engine cover, it has a compact structure and can be placed in front of the engine without compromising the sealing performance of the engine cover.This rotation sensor allows for phase adjustment. This has the effect that engine rotation can be accurately detected without being affected by the operation of the device.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional plan view of an engine according to an embodiment of the present invention, and FIG. 2 is a front view showing essential parts of the engine. DESCRIPTION OF SYMBOLS 11... Intake side camshaft, 12... Exhaust side camshaft, 15.16 Sprocket, 18... Chain, 20... Phase adjustment device, 22... Cam pulley, 24... Idler support member, 244... Positioning hole (fitted part), 30... Idle pulley (idler 931.32... Shielding plate (detector), 34... Timing belt, 38-40... Engine cover 42
...Positioning part (positioning member), 45.46...Rotation sensor. Patent applicant Mazda Co., Ltd. Agent Patent attorney Etsushi Kotani Diagram/38

Claims (1)

[Claims] 1. In an engine in which an intake side camshaft and an exhaust side camshaft are driven in conjunction with each other, and a phase adjustment device is provided to adjust the phase difference between one of the camshafts and a cam pulley attached to the camshaft. , an idler is rotatably arranged in front of the other camshaft, this idler is configured to rotate in synchronization with the cam pulley, a detector is provided on this idler, and a detector is provided on the inner surface of the engine cover that covers this idler. A rotation sensor mounting structure for an engine, characterized in that a rotation sensor for detecting the rotation of the detector is mounted. 2. In the engine rotation sensor mounting structure according to claim 1, a positioning member is provided protrudingly on the inner surface of the engine cover to which the rotation sensor is mounted, and the positioning member is inserted into the support portion of the idler. An engine rotation sensor mounting structure characterized by the following: