JP6581386B2 - Pulley with rotation detection element - Google Patents

Description

  The present invention relates to a pulley provided on a crankshaft of an automobile engine.

  A pulley attached to a shaft end of a crankshaft in an automobile engine constitutes a torsional damper for absorbing torsional vibration generated in the crankshaft by resonance in a predetermined vibration frequency range. As shown in FIG. 4, this type of pulley includes a hub 100 that is disposed outside the engine case 200 of the engine and has a cylindrical boss 101 having an inner diameter fixed to the shaft end of the crankshaft 400 by a bolt 401. Prepare. Further, in order to prevent engine oil existing in the machine (crank chamber) A from leaking out of the machine through the shaft hole on the inner peripheral surface of the shaft hole of the engine case 200 through which the shaft end of the crankshaft 400 is inserted, An oil seal 300 is attached. The oil seal 300 exhibits a sealing function against engine oil by having a main lip 301 facing the in-flight A side slidably in contact with the outer peripheral surface of the boss 101 of the hub 100 in the torsional damper ( For example, see Patent Document 1).

  However, in the case of the above-described structure, when muddy water, dust, or the like comes into the space B between the hub 100 and the engine case 200, such dust or the like is generated on the outer peripheral surface of the boss 101 of the hub 100 and the main part of the oil seal 300. By intervening in the sliding portion with the lip 301, the sealing function against the engine oil may be impaired, or the main lip 301 may be worn early.

  In view of this, it is known that a labyrinth seal LS composed of a zigzag gap is formed outside the oil seal 300 by, for example, an annular recess 102 formed in the hub 100 and an annular projection 201 formed in the engine case 200. However, in the case of the labyrinth seal LS, in order to avoid metal contact between the hub 100 and the engine case 200, there is a limit to reducing the clearance between the annular concave portion 102 and the annular convex portion 201. It is difficult to increase.

  On the other hand, the sensing mechanism for detecting the number of rotations of the crankshaft and detecting the crank angle in the engine has a pulsar with many protrusions formed in the shape of a gear on the outer periphery of a metal disk and is positioned inside the engine front cover. It is known that it is provided on the inside of the distributor, provided inside the distributor, or provided on the crank pulley (see Patent Document 2, for example).

  However, according to the sensing mechanism using a pulser in which a large number of protrusions are formed in the shape of a gear on the outer periphery of a metal disk, the problem is that the diameter cannot be reduced because the number of protrusions must be increased in order to perform detection with high accuracy. And the structure tends to be complicated.

Japanese Patent Laid-Open No. 2002-276738 Japanese Patent Laid-Open No. 11-28112

  The present invention has been made in view of the above points, and its technical problem is that in a pulley attached to the shaft end of the crankshaft, the intrusion of muddy water and dust and the rotation speed of the crankshaft or It is to satisfy both high-accuracy detection of the crank angle.

One aspect of the pulley with a rotation detecting element of the present invention is disposed on the outer side of the engine case and fixed to the shaft end of the crankshaft, and is provided on the outer side of the inner diameter cylindrical portion positioned on the inner periphery of the shaft hole of the engine case. A main body having an annular step portion having a larger diameter than the inner tube portion, a fitting tube portion press-fitted into the annular step portion , and extending from one end in the axial direction of the fitting tube portion toward the inner diameter side. A metal ring having a radial portion that contacts the end surface of the annular step portion, a seal tube portion projecting from the inner diameter end of the radial step portion toward the engine case, and an outer peripheral surface of the fitting tube portion And magnetized portions in which magnetic poles having different polarities are alternately magnetized at predetermined intervals in the circumferential direction, and the metal ring is attached to the shaft hole of the engine case and is connected to the shaft periphery of the crankshaft. From the oil seal to the main body side Only a dust lip extending to proximate faces the inner circumferential surface of the tubular sealing section.
Another aspect of the pulley with a rotation detection element of the present invention is an outer cylinder body disposed on the outer side of the engine case and fixed to the shaft end of the crankshaft, and located on the inner periphery of the shaft hole of the engine case; A main body having an annular step portion larger in diameter than the inner diameter cylindrical portion provided on the inner surface, a fitting cylinder portion press-fitted into the annular step portion , and an inner diameter side from one axial end of the fitting cylinder portion A metal ring comprising: a radial portion extending toward the end surface of the annular step portion; and a seal tube portion projecting from the inner diameter end of the radial portion toward the engine case; and the fitting tube portion A magnetized portion in which magnetic poles having different polarities are alternately magnetized at predetermined intervals in the circumferential direction, and the metal ring is attached to a shaft hole of the engine case to be attached to the outer periphery of the crankshaft. The main body from the oil seal that seals the shaft circumference Slidably to close and the dust lip extending toward the inner peripheral surface of the tubular sealing section.

  According to the pulley with the rotation detection element having the above-described configuration, the rotation detection element rotates integrally with the main body fixed to the shaft end of the crankshaft, and the movement of the N pole and the S pole magnetized in the magnetized portion is reduced. It is detected by a sensor arranged in a non-rotating state in close proximity to the direction. And the seal cylinder part in this rotation detecting element has a dust lip extending from an oil seal attached to the shaft hole of the engine case on its inner peripheral surface so as to be closely opposed or slidable, so that muddy water from the outside of the machine This prevents dust from entering. If the axial mounting error, axial dimensional tolerance, and axial displacement between the hub and the engine case are within the axial length of the seal tube, the dust lip is in close proximity to the inner peripheral surface of the seal tube. Alternatively, since a close contact state is ensured, a good sealing property can be obtained.

  According to the pulley with a rotation detection element according to the present invention, the rotation detection element magnetized by multipolar magnetism enables highly accurate detection of the rotation speed or crank angle of the crankshaft, and the axial direction between the hub and the engine case. Regardless of mounting error, axial dimensional tolerance, axial displacement, etc., muddy water and dust can be effectively prevented from entering the oil seal.

It is principal part sectional drawing which cut | disconnects and shows preferable embodiment of the pulley with a rotation detection element which concerns on this invention by the plane which passes along an axial center. It is a section perspective view showing a rotation detection element in a preferred embodiment of a pulley with a rotation detection element according to the present invention by cutting along a plane passing through an axis. It is explanatory drawing which shows the output waveform at the time of rotation detection. It is a fragmentary sectional view which cuts and shows an example of the pulley with a rotation detection element which concerns on background art by the plane which passes along an axial center.

  Hereinafter, preferred embodiments of a pulley with a rotation detection element according to the present invention will be described with reference to the drawings. First, in FIG. 1, reference numeral 1 is a pulley, 2 is an oil seal, 3 is an engine case in an automobile engine, 4 is a crankshaft, and A is the interior of the machine (the space inside the engine case 3).

  The pulley 1 includes a configuration (not shown) in which an annular mass body is concentrically attached via an annular rubber on the outer peripheral side of a hub 11 that is fixed to the shaft end of the crankshaft 4 and disposed outside the engine case 3. A torsional damper that absorbs the torsional vibration generated in the crankshaft 4 by resonance in a predetermined vibration frequency range in which the amplitude is maximum is configured. The hub 11 corresponds to the “main body” described in claim 1.

  The hub 11 is extrapolated to the shaft end of the crankshaft 4 and is fixed by a bolt 41, and is located on the inner periphery of the shaft hole of the engine case 3, and the inner diameter cylindrical portion 11a on the outer side of the inner diameter cylindrical portion 11a. An annular step portion 11b formed with a larger diameter, and a disk portion 11c that expands from an end of the annular step portion 11b outside the machine.

  A rotation detecting element 12 is attached to the annular step portion 11 b in the hub 11 of the pulley 1. The rotation detecting element 12 includes a metal ring 121 and a magnetized portion 122.

  Specifically, the metal ring 121 in the rotation detecting element 12 is manufactured by punching a metal plate or the like, and is press-fitted to the outer peripheral surface of the annular step portion 11b in the hub 11 with an appropriate margin. A fitting cylinder part 121a, a radial part 121b extending from one end in the axial direction of the fitting cylinder part 121a to the inner diameter side and coming into contact with the end surface of the annular step part 11b in the hub 11, and further, the radial part 121b It consists of the seal cylinder part 121c which protruded toward the engine case 3 side from the inner diameter end.

  On the other hand, the magnetized portion 122 is made of a magnetic rubber obtained by mixing a magnetic powder with a rubber elastic body, and is integrally joined (integratedly molded) to the outer peripheral surface of the fitting cylindrical portion 121a in the metal ring 121. As shown in FIG. 2, magnetic poles (N and S poles) 122a and 122b having different polarities are alternately magnetized (multipolar magnetization) at a predetermined pitch in the circumferential direction. Further, of the magnetic poles 122a and 122b, the magnetic pole located at one place in the circumferential direction is specified, for example, for the purpose of controlling the ignition timing of the engine, such as the crank angle that becomes the TDC (Top Dead Center) of the piston. As a measurement origin for detecting the crank angle, the magnetization pitch in the circumferential direction is different.

  The oil seal 2 includes a metal ring 21, an outer peripheral seal portion 22 made of a rubber elastic body provided on the outer peripheral surface of the metal ring 21 and press-fitted into the inner peripheral surface of the shaft hole 31 of the engine case 3, A main lip 23 formed of a rubber elastic body provided on the inner diameter portion of the ring 21 and extending toward the in-machine A side, and a dust lip 24 formed of a rubber elastic body provided on the inner diameter portion of the metal ring 21 and extending on the opposite side of the main lip 23. Is provided. The front end 23a of the main lip 23 is slidably brought into close contact with the outer peripheral surface of the inner diameter cylindrical portion 11a of the hub 11 of the pulley 1, and the outer periphery of the front end of the dust lip 24 is sealed with the cylindrical portion of the metal ring 121 in the rotation detecting element 12. It is brought into close contact with or slidable on the inner peripheral surface of 121c.

  In the space B between the engine case 3 and the pulley 1, the sensor 5 made of a Hall element, a magnetoresistive element or the like has its detection surface 5 a close to the outer peripheral surface of the magnetized portion 122 of the rotation detection element 12. For example, it is arranged in a non-rotating state by being attached to the engine case 3 side. The sensor 5 constitutes a magnetic rotary encoder together with the rotation detection element 12.

  That is, in this magnetic rotary encoder, when the rotation detecting element 12 rotates integrally with the crankshaft 4, the sensor 5 causes the inner peripheral side of the detecting surface 5a to face the magnetic poles 122a and 122b (N pole and S pole) of the magnetized portion 122. ) Alternately pass, a signal having a waveform corresponding to a change in the magnetic field is output as shown in FIG. In the output waveform shown in FIG. 3, the long half-wavelength portion (the portion indicated by λ <b> 1) corresponds to the portion having a different magnetization pitch at one place in the circumferential direction of the magnetized portion 122 described above. That is, a portion indicated by λ1 is formed in the output waveform from the sensor 5 for each rotation, which becomes the crank angle measurement origin.

  In the pulley with the rotation detection element configured as described above, the pulley 1 (torsional damper) is vibrated in the torsional direction in the vibration frequency region where the torsional amplitude of the crankshaft 4 is maximized, thereby causing the hub 11 to rotate. A dynamic vibration absorption system composed of an annular rubber and an annular mass on the outer peripheral side resonates, and a torque due to the vibration displacement in the torsion direction is generated in a direction opposite to the torque due to the input vibration, thereby reducing the torsional vibration of the crankshaft 4. It exhibits a vibration absorbing effect.

  On the other hand, in the oil seal 2, the outer peripheral seal portion 22 is closely fitted to the inner peripheral surface of the shaft hole 31 of the engine case 3, and the tip 23 a of the main lip 23 is the outer peripheral surface of the inner diameter cylindrical portion 11 a of the hub 11 in the pulley 1. The engine oil in the machine A is prevented from leaking from the shaft hole 31 by being slidably in close contact with each other.

  When the crankshaft 4 rotates, the hub 11 of the pulley 1 and the rotation detection element 12 attached to the annular stepped portion 11b also rotate together, and the magnetic pole 122a magnetized by the magnetized portion 122 of the rotation detection element 12. , 122b (N pole and S pole), a pulse signal having a waveform corresponding to a change in the magnetic field due to the movement in the circumferential direction is output from the sensor 5, so that the rotation speed of the crankshaft 4 and the The crank angle can be measured. In this case, it is possible to improve measurement accuracy by narrowing the magnetization pitch of the magnetic poles 122a and 122b (increasing the number of magnetic poles 122a and 122b).

  And on the inner peripheral surface of the seal cylinder part 121c of the metal ring 121 in the rotation detecting element 12, the outer periphery of the tip of the dust lip 24 provided on the oil seal 2 on the outer side of the main lip 23 is opposed to Since it is slidably in close contact, it is possible to effectively prevent muddy water, dust, and the like flying from outside the machine into the space B between the hub 11 and the engine case 3 from entering the main lip 23 side of the oil seal 2. Can do. That is, the rotation detection element 12 has both a function as a rotor of a magnetic rotary encoder for detecting the rotation of the crankshaft 4 and a function as a means for preventing intrusion of muddy water, dust, and the like.

  Further, if the labyrinth seal is configured by making the dust lip 24 non-contact with the inner peripheral surface of the seal cylindrical portion 121c of the metal ring 121 in the rotation detecting element 12, the dust lip 24 is formed on the seal cylindrical portion 121c. Even if it contacts the inner peripheral surface, metal contact does not occur, and no problem occurs. Therefore, the muddy water that tries to enter from the outer peripheral side with the gap between the dust lip 24 and the seal cylinder 121c as narrow as possible. And the sealing effect against dust can be improved.

  Further, the axial positional relationship between the hub 11 and the engine case 3 varies due to axial mounting errors, axial dimensional tolerances, and axial displacements of the hub 11, the oil seal 2, the crankshaft 4, and the like. However, if such variation in the axial position is within the range of the axial length of the seal cylinder part 121c of the metal ring 121 in the rotation detecting element 12, the dust strip 24 is formed on the inner peripheral surface of the seal cylinder part 121c. Since the outer periphery of the tip is in close contact with each other or slidably secured, good sealing performance against muddy water and dust can be obtained.

  In the above-described embodiment, the hub 11 is described as being a hub of a torsional damper. However, for example, a structure in which a pulley for transmitting power to an auxiliary machine is connected via a coupling rubber is annular. The present invention can be similarly applied to a hub of a torque fluctuation absorbing damper (damper pulley) provided with a dynamic vibration absorption system composed of rubber and an annular mass body, and a pulley that does not constitute a damper.

1 Pulley 11 Hub (main body)
12 Rotation detection element 121 Metal ring 121c Seal cylinder portion 122 Magnetized portion 2 Oil seal 24 Dustrip 3 Engine case 4 Crankshaft 5 Sensor

Claims (2)

An inner diameter cylindrical portion that is disposed outside the engine case and is fixed to the shaft end of the crankshaft and is positioned on the inner periphery of the shaft hole of the engine case, and an annular step that is larger in diameter than the inner diameter cylindrical portion provided outside the machine A body having a portion;
A fitting tube that is press-fitted into the annular step portion, which abuts against the radial portion on the end face of the annular stepped portion extends to the inner diameter side from one axial end of the fitting cylinder, of the radial portion A metal ring including a seal tube portion projecting from the inner diameter end toward the engine case,
Magnetized portions joined to the outer peripheral surface of the fitting cylinder portion, and magnetic poles having different polarities are alternately magnetized at predetermined intervals in the circumferential direction;
With
The metal ring is attached to the shaft hole of the engine case and has a dust lip extending from the oil seal that seals the shaft periphery of the crankshaft toward the main body side to be opposed to the inner peripheral surface of the seal cylinder portion.
A pulley with a rotation detecting element. An inner diameter cylindrical portion that is disposed outside the engine case and is fixed to the shaft end of the crankshaft and is positioned on the inner periphery of the shaft hole of the engine case, and an annular step that is larger in diameter than the inner diameter cylindrical portion provided outside the machine A body having a portion;
A fitting tube that is press-fitted into the annular step portion, which abuts against the radial portion on the end face of the annular stepped portion extends to the inner diameter side from one axial end of the fitting cylinder, of the radial portion A metal ring including a seal tube portion projecting from the inner diameter end toward the engine case,
Magnetized portions joined to the outer peripheral surface of the fitting cylinder portion, and magnetic poles having different polarities are alternately magnetized at predetermined intervals in the circumferential direction;
With
The metal ring is attached to the shaft hole of the engine case so that a dust lip extending from the oil seal that seals the shaft periphery of the crankshaft toward the main body is slidable on the inner peripheral surface of the seal cylinder portion. Close
A pulley with a rotation detecting element.

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