JP6336296B2 - Engine rotation sensor device, marine engine equipped with the same - Google Patents

Description

  The present invention relates to an engine rotation sensor device for detecting rotation information such as an absolute angle position and a rotation speed of a crankshaft, and a marine engine including the same.

  A reciprocating piston engine (reciprocating engine) is provided with a rotation sensor device that detects rotation information such as an absolute angular position and a rotation speed of a crankshaft. In a relatively small engine such as an automobile engine, a rotation detection target portion such as a protrusion or a notch is provided at the peripheral portion of a rotary member such as a flywheel or a pulley that rotates together with the crankshaft, and the movement of this rotation detection target portion is The rotation information of the crankshaft is detected by a rotation detection unit such as an optical sensor or a magnetic force sensor provided on the crankcase side.

  The same applies to a large marine engine. For example, like the rotation sensor device 101 shown in FIG. 5, the sensor shaft 5 is attached to the shaft end portion of a huge crankshaft 3 supported on the main bearing 2 of the crankcase 1. The sensor shaft 5 is coaxially connected via a special flexible joint 6 (flexible joint) and is provided at the tip of the sensor shaft 5 while being supported by a dedicated sensor bearing 7 provided on the end face of the crankcase 1. The rotation state of the detected rotating body 8 is detected by a rotation detector 9 fixed in the vicinity of the sensor bearing 7.

  For example, as shown in FIG. 2 of Patent Document 1, in a large marine diesel engine, the rotation of the crankshaft 3 is transmitted to the rotation shaft of the high-pressure pump 4 by the gears 2 a and 3 to drive the high-pressure pump 4. In addition, it is known that the rotation of the rotary shaft of the high-pressure pump 4 is detected by an angle sensor 8 to detect the rotation of the crankshaft 3.

JP 2000-145529 A

  In the crankshaft rotation detection structure described in Patent Document 1, since the auxiliary machinery such as the high pressure pump 4 rotates at a higher speed than the crankshaft 3, the number of teeth of the gear 2a and the number of teeth of the gear 3 are reduced. Must be designed to be very different. For this reason, the rotation data of the rotating shaft detected by the angle sensor 8 has to be decelerated to a fraction so that it becomes the rotation data of the crankshaft 3, and there is a possibility that the detection accuracy is lowered.

  The present invention has been made in view of the above circumstances, and provides an engine rotation sensor device capable of accurately detecting rotation information of a crankshaft with a simple and inexpensive configuration, and a marine engine including the same. The purpose is to do.

The present invention employs the following means in order to solve the above problems.
An engine rotation sensor device according to the present invention comprises an axis different from a crankshaft, a sensor shaft driven by the crankshaft, and a constant speed rotation transmission mechanism for rotating the crankshaft and the sensor shaft at a constant speed. And a detected rotating body provided on the sensor shaft, and a rotation detecting unit that detects the movement of the detected rotating body.

  According to the rotation sensor device having the above configuration, the sensor shaft that is driven by the crankshaft of the engine and is provided as a separate shaft from the crankshaft is rotationally driven at a constant speed with respect to the crankshaft by the constant speed rotation transmission mechanism. Then, the movement of the detected rotating body provided on the sensor shaft is detected by the rotation detecting unit.

  Since the sensor shaft is a separate shaft having a different axis from the crankshaft, for example, the crankshaft has a remarkably larger diameter than the sensor shaft, and the rotational shaft has a larger amount of deflection in the radial direction and the axial direction than the sensor shaft. Even if this is the case, the crankshaft and the sensor shaft need not be connected by a special and expensive flexible joint or the like. By omitting the flexible joint in this way, the configuration of the rotation sensor device can be made simple and inexpensive.

  In addition, since the sensor shaft is rotationally driven at the same speed as the crankshaft, the rotation information of the sensor shaft becomes the rotation information of the crankshaft as it is. For this reason, the rotation information of the crankshaft can be detected with high accuracy.

  In the above configuration, it is preferable that the constant speed rotation transmission mechanism can absorb a change in an inter-axis distance between the crankshaft and the sensor shaft.

  Thus, if the constant speed rotation transmission mechanism can absorb the change in the distance between the crankshaft and the sensor shaft, the flexible joint provided on the sensor shaft is omitted or simplified, and the configuration of the rotation sensor device is simple and inexpensive. Can be.

In the above structure, the constant velocity rotation transmission mechanism is fixed to an end of the crankshaft, and a small-diameter drive kinematic gear than said crankshaft meshes with said driving gear is fixed to the sensor shaft, the It is good also as a structure provided with the driven gear which has the same number of teeth as a drive gear.

  Thus, if the rotation of the crankshaft is transmitted to the sensor shaft by the drive gear and the driven gear, the crank using the width of the meshing margin between the drive gear and the driven gear (backlash in the inter-shaft distance direction) is used. A change in the distance between the shaft and the sensor shaft can be absorbed, which can contribute to omission or simplification of the flexible joint.

  In the above configuration, the axial center position of the sensor shaft is below the axial center position of the crankshaft, and when the engine is stopped, the engagement allowance between the drive gear and the driven gear is the maximum allowable. It is preferable to set the value.

According to the above configuration, when the engine is stopped and the crankshaft comes to the lowest part in the bearing gap due to gravity, the meshing allowance between the gears becomes an allowable maximum value. For this reason, when the engine is operated and the position of the crankshaft is raised, the meshing margin tends to decrease, and there is no possibility that the meshing margin becomes excessive, that is, the backlash becomes excessively small.
Therefore, it is possible to prevent problems such as a decrease in absorbability of changes in the distance between the crankshaft and the sensor shaft due to insufficient backlash during engine operation, and damage and abnormal wear of the gear, sensor shaft, sensor bearing, etc. be able to.

  Further, in the above configuration, the constant speed rotation transmission mechanism includes a drive rotation member fixed to the crankshaft and having a meshing portion formed on an outer peripheral portion, and a meshing portion fixed to the sensor shaft and formed on an outer peripheral portion. A driven rotation member, and a meshing winding member wound around the drive rotation member and the driven rotation member and meshing with the meshing portion, and rotating the drive rotation member and the driven rotation member at a constant speed. It is good also as a structure provided.

  If the constant speed rotation transmission mechanism is configured as described above, a change in the distance between the crankshaft and the sensor shaft can be absorbed by the meshing winding member. For example, the mesh winding member may be loosely wound as a chain or a cogged belt, and the slack may be absorbed by the tensioner. Thereby, the change of the dimension between axes can be absorbed using a general and simple machine element.

Moreover, the marine engine which concerns on this invention is equipped with the rotation sensor apparatus of the engine of the said either structure, It is characterized by the above-mentioned.
According to this marine engine, the rotation information of the crankshaft can be accurately detected with a simple and inexpensive configuration suitable for the marine engine.

  As described above, in the engine rotation sensor device according to the present invention and the marine engine including the engine rotation information, the rotation information of the crankshaft can be accurately detected with a simple and inexpensive configuration.

It is the longitudinal cross-sectional view of the crankshaft front end vicinity of the large-sized marine diesel engine which shows 1st Embodiment of this invention, and a rotation sensor apparatus. It is a front view of the engine and rotation sensor apparatus by the II arrow of FIG. FIG. 3 is a front view of a constant speed rotation transmission mechanism as viewed in the direction of arrows III-III in FIG. 1, (a) showing the magnitude of the meshing allowance when the engine is stopped and (b) when the engine is operating. It is a front view of the constant velocity rotation transmission mechanism which shows 2nd Embodiment of this invention. It is the longitudinal cross-sectional view of the crankshaft front end vicinity and rotation sensor apparatus of the marine large sized diesel engine which shows the prior art.

  Embodiments of a rotation sensor device according to the present invention will be described below with reference to the drawings.

[First Embodiment]
FIG. 1 is a longitudinal sectional view of the vicinity of a crankshaft front end portion of a large marine diesel engine and a rotation sensor device 51 showing a first embodiment of the present invention, and FIG. 2 is an engine and rotation sensor device taken along the arrow II in FIG. FIG.

  The rotation sensor device 51 is provided in front of the crankcase 1 in the large diesel engine, and detects rotation information (absolute angle position, rotation speed, etc.) of the crankshaft 3 of the large diesel engine.

  The crankshaft 3 is pivotally supported by a main bearing 2 provided on the crankcase 1, a front end surface 3 a thereof protrudes from the front surface of the crankcase 1, and an annular thrust stopper 4 surrounding the protruding portion is provided on the front surface of the crankcase 1. It is fixed to. The thrust stopper 4 is a regulating member that limits the movement of the crankshaft 3 in the axial direction to a predetermined range (about several millimeters).

  A cylindrical gear housing 11 is fixed to the thrust stopper 4, and a sensor gear chamber 12 is provided inside the gear housing 11. A cylindrical sensor bearing 13 is provided through the front surface 11 a of the gear housing 11, and a sensor shaft 15 is pivotally supported on the sensor bearing 13. The sensor shaft 15 has a different axis from the crankshaft 3 and is a rotary shaft that is supported in parallel with the crankshaft 3 and is rotationally driven by the crankshaft 3 via a gear drive mechanism 21 described later.

  The shaft support position of the sensor shaft 15 is preferably lower than the axial center position of the crankshaft 3, and the sensor shaft 15 is disposed vertically below the axis of the crankshaft 3 as shown in FIGS. Ideally. However, as long as it is below the crankshaft 3, it may be at a position slightly deviated from vertically below.

  A disk-shaped (rotor-shaped) detected rotating body 18 is provided at the tip of the sensor shaft 15, while a rotation detecting section 19 having a shape surrounding the detected rotating body 18 is fixed to the gear housing 11 side. ing. Then, the rotation detector 19 detects the movement of the detected rotating body 18 that rotates together with the sensor shaft 15. Thus, the sensor shaft 15 is a dedicated rotation shaft for rotating the detected rotating body 18.

  A gear drive mechanism 21 is accommodated in the sensor gear chamber 12 as a constant speed rotation transmission mechanism that rotates the crankshaft 3 and the sensor shaft 15 in synchronization with each other at a constant speed. The gear drive mechanism 21 includes a drive gear 22 fixed to the crankshaft 3 and a driven gear 23 fixed to the sensor shaft 15. The drive gear 22 and the driven gear 23 have the same number of teeth and mesh with each other. The gear drive mechanism 21 causes the crankshaft 3 and the sensor shaft 15 to rotate synchronously at a constant speed.

  Since the crankshaft 3 has a large diameter, it can swing several millimeters in the radial direction inside the main bearing 2. Further, it moves about several millimeters within the range allowed by the thrust stopper 4 in the axial direction. The distance between the crankshaft 3 and the sensor shaft 15 changes due to the radial deflection of the crankshaft 3, but the gear drive mechanism 21 can absorb the change in the distance between the shafts. This is because the sensor bearing 13 that supports the sensor shaft 15 is fixed to the crankcase 1 via the gear housing 11 and is not easily affected by the movement of the crankshaft 3 in the radial direction.

  That is, when the crankshaft 3 is displaced in the radial direction, the meshing margin between the drive gear 22 and the driven gear 23 changes, but tooth skipping does not occur between both the gears 22 and 23. For this reason, the rotation of the crankshaft 3 is always transmitted to the sensor shaft 15. Further, the swing of the crankshaft 3 in the axial direction is absorbed by the drive gear 22 sliding in the axial direction with respect to the driven gear 23.

3 is a front view of the gear drive mechanism 21 as viewed in the direction of arrows III-III in FIG. 1, (a) when the engine is stopped, and (b) between the drive gear 22 and the driven gear 23 when the engine is operating. The sizes of the meshing margins H1 and H2 are shown.
Here, the shaft center position of the sensor shaft 15 with respect to the crankshaft 3 is set so that the relationship between the meshing margin H1 when the engine is stopped (a) and the meshing margin H2 when the engine is operating (b) is H1> H2. Has been.
Further, the meshing allowance H1 when the engine is stopped (a) is set to an allowable maximum value, and the meshing allowance H2 when the engine is operated (b) is set to be equal to or greater than the allowable minimum value.

  When the engine is stopped, the crankshaft 3 comes into contact with the lowest part of the main bearing 2 by its own weight. On the other hand, when the engine is operated, the crankshaft 3 is lifted from the lowest portion of the main bearing 2 due to the entrainment of lubricating oil and the shaft behavior determined by the shaft load characteristics and the rotation direction. Thus, the distance between the crankshaft 3 and the sensor shaft 15 changes by ΔH when the engine is stopped and when the engine is operating. In this way, even if the position of the crankshaft 3 is increased, the meshing margin H2 between the drive gear 22 and the driven gear 23 does not fall below the allowable minimum value.

  The rotation sensor device 51 is configured as described above. In the above embodiment, the sensor shaft 15 is driven by the crankshaft 3. However, the sensor shaft 15 is not limited to the crankshaft 3, and may be a camshaft as long as it is a rotating shaft that rotates in proportion to the rotational speed of the engine. It is also conceivable that the sensor shaft 15 is rotationally driven by a shaft, a balancer shaft or the like.

  When the crankshaft 3 rotates, the rotation is transmitted to the sensor shaft 15 through meshing of the drive gear 22 and the driven gear 23, and the sensor shaft 15 is driven to rotate at a constant speed with the crankshaft 3. The detected rotating body 18 rotates together with the sensor shaft 15, and the rotation of the detected rotating body 18 is detected by the rotation detector 19 as rotation information (absolute angular position, rotational speed, etc.) of the crankshaft 3.

  The sensor shaft 15 of the rotation sensor device 51 is a separate shaft having an axis different from that of the crankshaft 3, and thus is a rotary shaft having a large diameter and a large amount of deflection in the radial direction and the axial direction, like the crankshaft 3. However, it is not necessary to connect the crankshaft 3 and the sensor shaft 15 with a flexible joint which is a complicated and expensive dedicated component as in the prior art. By omitting the flexible joint in this way, the configuration of the rotation sensor device 51 can be made simple and inexpensive.

  Moreover, since the sensor shaft 15 is rotationally driven at the same speed as the crankshaft 3, the rotation information of the sensor shaft 15 becomes the rotation information of the crankshaft 3 as it is. Therefore, the rotation information of the crankshaft 3 can be detected with high accuracy.

Further, the rotation of the crankshaft 3 is transmitted to the sensor shaft 15, and the drive gear 22 fixed to the crankshaft 3 is engaged with the drive gear 22 fixed to the sensor shaft 15 and has the same number of teeth as the drive gear 22. A gear drive mechanism 21 having a driven gear 23 is provided.
In this way, if the rotation of the crankshaft 3 is transmitted to the sensor shaft 15 by the drive gear 22 and the driven gear 23, the engagement allowances H1 and H2 between the drive gear 22 and the driven gear 23 (back in the inter-axis distance direction). Rush) can be used to absorb the change ΔH in the inter-shaft distance between the crankshaft 3 and the sensor shaft 15 caused by the swing of the crankshaft 3, which also contributes to the omission or simplification of the flexible joint. be able to.

  Further, in the rotation sensor device 51, when the axial center position of the sensor shaft 15 is lower than the axial center position of the crankshaft 3, the crankshaft 3 comes to the lowest part in the bearing gap due to gravity when the engine is stopped. The meshing margin H1 between the gears 22 and 23 is an allowable maximum value.

  For this reason, when the engine is operated and the position of the crankshaft 3 is raised, the meshing margin H1 tends to decrease to H2, and there is no possibility that the meshing margin becomes excessive, that is, the backlash becomes excessively small. Therefore, the absorbability of the change ΔH in the inter-shaft distance between the crankshaft 3 and the sensor shaft 15 due to insufficient backlash during engine operation is reduced, and the gears 22, 23, the sensor shaft 15, the sensor bearing 13, etc. Problems such as breakage and abnormal wear can be prevented.

[Second Embodiment]
FIG. 4 is a front view of a constant speed rotation transmission mechanism showing a second embodiment of the present invention.
In the first embodiment shown in FIG. 1 to FIG. 3, the gear drive mechanism 21 is used as a constant speed rotation transmission mechanism that rotates the crankshaft 3 and the sensor shaft 15 in synchronization with each other at a constant speed. In the second embodiment, a winding drive mechanism 25 using a chain is used as a constant speed rotation transmission mechanism.

The winding drive mechanism 25 includes a drive sprocket 26 (drive rotation member), a driven sprocket 27 (driven rotation member), a chain 28 (meshing and winding member), and a tension sprocket 29 that absorbs slackness of the chain 28. It has.
The drive sprocket 26 is fixed to the crankshaft 3 and teeth 26a (meshing portions) are formed on the outer peripheral portion, and the driven sprocket 27 is fixed to the sensor shaft 15 and teeth 27a (meshing portions) are formed on the outer peripheral portion. Yes. The number of teeth 26a of the drive sprocket 26 and the number of teeth 27a of the driven sprocket 27 are the same.

  The chain 28 is wound around the drive sprocket 26 and the driven sprocket 27 and meshes with the teeth 26a and 27a, and the drive sprocket 26 and the driven sprocket 27 are rotated in synchronization with each other at a constant speed. The tension sprocket 29 is provided on the chain line on the loose side of the chain 28. By the winding drive mechanism 25, the crankshaft 3 and the sensor shaft 15 rotate in synchronization with each other at a constant speed.

  As described above, when the constant speed rotation transmission mechanism is the winding drive mechanism 25 using the sprockets 26 and 27 and the chain 28, the change in the inter-shaft distance between the crankshaft 3 and the sensor shaft 15 can be reduced. It can be absorbed by the sprocket 29). Thereby, the change of the dimension between the crankshaft 3 and the sensor shaft 15 can be absorbed using a general and simple machine element.

  Moreover, the degree of freedom of the support position of the sensor shaft 15 can be increased as compared with the case of the first embodiment. That is, in the gear drive mechanism 21 of the first embodiment, the rotation of the crankshaft 3 is transmitted to the sensor shaft 15 by the gears 22 and 23, and the outer diameter of the gears 22 and 23 cannot be increased so much. The sensor shaft 15 had to be supported near the crankshaft 3.

  On the other hand, in the winding drive mechanism 25 of the second embodiment, the shaft support position of the sensor shaft 15 can be separated from the crankshaft 3 by extending the length of the chain 28. Furthermore, it is not necessary to make the shaft center position of the sensor shaft 15 lower than the shaft center position of the crankshaft 3 as in the first embodiment, and this also increases the degree of freedom of the shaft support position of the sensor shaft 15. it can.

  By changing the sprockets 26 and 27 of the winding drive mechanism 25 to cogged pulleys (toothed pulleys) and changing the chain 28 to cogged belts (toothed belts), the same operations and effects as described above can be achieved. In addition, since lubrication is unnecessary, maintenance can be improved as compared with the gear type and chain type.

  As described above, according to the rotation sensor device 51 according to the present embodiment, the flexible joint conventionally provided between the crankshaft 3 and the sensor shaft 15 can be omitted or simplified. The rotation information of the crankshaft 3 can be obtained accurately.

  Moreover, in the marine engine provided with the rotation sensor device 51, the rotation information of the crankshaft can be detected with high accuracy and the reliability of the engine can be improved with a simple and inexpensive configuration suitable for the marine engine.

  It should be noted that the present invention is not limited to the configuration of the embodiment described above, and appropriate modifications and improvements can be made within the scope not departing from the gist of the present invention, and application fields can be changed. Embodiments to which changes and improvements are added are also included in the scope of the right of the present invention.

For example, in the above-described embodiment, an example in which the rotation sensor device according to the present invention is applied to a large marine diesel engine has been described.
Further, the relative positional relationship between the crankshaft 3 and the sensor shaft 15 is not limited to that of the above embodiment.

DESCRIPTION OF SYMBOLS 1 Crankcase 2 Main bearing 3 Crankshaft 4 Thrust stopper 11 Gear housing 12 Sensor gear chamber 13 Sensor bearing 15 Sensor shaft 18 Detected rotating body 19 Rotation detection part 21 Gear drive mechanism (constant speed rotation transmission mechanism)
22 drive gear 23 driven gear 25 winding drive mechanism (constant speed rotation transmission mechanism)
26 Drive sprocket (drive rotary member)
26a Teeth (meshing part)
27 Driven sprocket (driven rotating member)
27a Teeth (meshing part)
28 Chain (meshing member)
29 Tension sprocket H1, H2 Amount of meshing ΔH between the drive gear and the driven gear Amount of change in the distance between the crankshaft and the sensor shaft

Claims (2)

A sensor shaft having an axis different from the crankshaft and driven by the crankshaft;
A constant speed rotation transmission mechanism for rotating the crankshaft and the sensor shaft at a constant speed;
A detected rotating body provided on the sensor shaft;
A rotation detector for detecting the movement of the detected rotating body;
With
The constant velocity rotation transmission mechanism is fixed to an end of the crankshaft, and a small-diameter drive kinematic gear than said crankshaft meshes with said driving gear is fixed to the sensor shaft, the same number of teeth and the drive gear And a driven gear having a function of absorbing a change in an inter-axis distance between the crankshaft and the sensor shaft,
A central axial position of the sensor shaft is located below the axis position of the crankshaft are set as engagement allowance between the drive gear when stopping the engine and the driven gear is the allowable maximum value The engine rotation sensor device.   A marine engine comprising the engine rotation sensor device according to claim 1.

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