JP2008082515A - Pulley unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pulley unit capable of preventing deterioration in the service life of a belt by detecting a belt slip itself. <P>SOLUTION: The pulley unit is equipped with a movable body 11 which is relatively rotatable with respect to a pulley 5 and rotates with a belt 7, a sensor 13 for detecting the relative rotation of the movable body 11 with respect to the pulley 5, and a processing means 14 for generating a signal for reducing the load of the belt 7 in response to a signal from the sensor 13. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a pulley unit, and more particularly to a pulley unit equipped in an auxiliary machine (for example, an alternator, a compressor, etc.) driven from a crankshaft of an automobile engine or the like via a belt.

As a pulley unit used in an engine accessory such as an alternator, a pulley unit having a built-in one-way clutch for absorbing rotational fluctuation is known in order to prevent belt life from being reduced due to belt slip (see Patent Document 1). ).
JP-A-11-30312

  According to the pulley unit of Patent Document 1 described above, the rotational fluctuation can be absorbed by idling at the time of deceleration by the function of the one-way clutch, but the rotational fluctuation at the time of acceleration cannot be absorbed. In some cases, it cannot be avoided, which causes a reduction in belt life.

  An object of the present invention is to provide a pulley unit that can detect belt slip itself and thereby prevent a reduction in belt life.

  A pulley unit according to the present invention comprises a pulley around which a belt is wound and a rotating shaft that rotates as the pulley rotates, and a movable body that can rotate relative to the pulley and rotate together with the belt. The sensor further comprises a sensor for detecting the relative rotation of the movable body with respect to the pulley, and a processing means for creating a signal for reducing the load on the belt in accordance with the signal of the sensor.

  This pulley unit can be used in an auxiliary machine such as an automobile alternator and a compressor for an air conditioner and other various devices. In this case, a one-way clutch may be incorporated, or a one-way clutch may not be incorporated.

  The movable body may be ring-shaped or non-ring-shaped and provided at predetermined intervals in the circumferential direction. The movable body is pressed against the belt by an urging member, for example.

  When the belt slips with respect to the pulley, the movable body rotates integrally with the belt, and a relative speed is generated between the pulley and the movable body. The sensor is capable of detecting this relative speed, and a known rotation sensor (for example, a combination of a pulsar ring and a magnetic sensor, or a plurality of non-ring-shaped movable bodies made of a conductor are arranged at equal intervals in the circumferential direction. And the like that count the number of ON / OFF times of the energized state) can be used as appropriate.

  The sensor may be provided on a pulley or may be provided on a rotating shaft that rotates integrally with the pulley.

  The processing means performs necessary processing when a relative speed occurs (for example, when a slip of 2% or more occurs). For example, in the case of a pulley unit for an alternator, a signal for reducing power generation by the alternator is provided. By outputting, the load on the belt is reduced and belt slip is eliminated.

  According to the pulley unit of the present invention, the belt slip is detected by detecting the relative speed generated between the pulley and the movable body by the sensor, and in response thereto, a signal for reducing the belt load is output from the processing means. Therefore, a reduction in belt life can be prevented.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 and 2 show an embodiment of a pulley unit according to the present invention.

  As shown in FIG. 1, the pulley unit (1) is arranged at a portion that connects a drive unit of an automobile engine and a power generating rotary shaft of the alternator. The pulley unit (2) and the rotary shaft (3) are connected to each other. A rolling bearing (4) provided between the pulley, a pulley (5) attached to the outer periphery of the rotating shaft (3) with a nut (6), a belt (7) wound around the pulley (5), A belt slip detection device (8) for detecting belt slip.

  The pulley (5) includes a small diameter cylindrical portion (5a) fixed to the rotating shaft (3), a large diameter cylindrical portion (5b) around which the belt (7) is wound, and a disk portion connecting these (5c).

  The belt slip detection device (8) includes a movable body (11) that can rotate relative to the pulley (5) and rotates together with the belt (7), and the movable body (11) is connected to the pulley (5) and the belt (7). A leaf spring (12) as an urging means that is pressed against both, and a rotation sensor that is provided on the small diameter cylindrical portion (5a) of the pulley (5) and detects the relative rotation of the movable body (11) with respect to the pulley (5) (13) and processing means (14) for creating a signal for reducing the load on the belt (7) in accordance with the signal from the rotation sensor (12).

  The movable body (11) is made of a conductor so that its radially outer portion is in contact with the end surface of the belt (7) and its radially intermediate portion is in contact with the end surface of the large-diameter cylindrical portion (5b) of the pulley (5). As shown in FIG. 2, a plurality are arranged at equal intervals in the circumferential direction.

  One end of the leaf spring (12) is supported by a flange portion (5d) provided at the end of the small diameter cylindrical portion (5a) of the pulley (5), and the other end is applied to the movable body (11). Thus, the movable body (11) is biased by the leaf spring (12) so as to contact the end surface of the pulley (5) and the end surface of the belt (7), and the end surface of the pulley (5) and the belt (7 ), The movable body (11) rotates integrally with the belt (7).

  The rotation sensor (13) counts the number of ON / OFF states in the energized state. When the movable body (11) is in the position indicated by the solid line in FIG. 2, the ON signal is indicated by a two-dot chain line in FIG. When the movable body (11) is present at the indicated position, an OFF signal is output, and the number of repetitions is counted to detect the relative speed of the movable body (11) with respect to the pulley (5).

  The processing means (14) is connected so as to output a signal to the control unit of the automobile, and the relative speed of the movable body (11) with respect to the pulley (5) obtained by the rotation sensor (13) is a predetermined value ( For example, when the slip amount exceeds 2%, a signal for reducing the power generation of the alternator is output to the control unit of the automobile. As a result, the load on the belt (7) is reduced and the belt slip is eliminated, so that the life of the belt (7) is prevented from being reduced.

  The above processing means (14) reduces the load on the belt (7) when the relative speed exceeds a predetermined value. The load may be increased or decreased. The pulley unit (1) can be applied to, for example, a compressor in addition to an alternator. In this case, the compressor breakage can be detected from the belt slip, and the compressor breakage is detected early. can do. The pulley unit (1) is applicable to various devices other than this.

FIG. 1 is a longitudinal sectional view showing an embodiment of a pulley unit according to the present invention. FIG. 2 is a cross-sectional view of the main part.

Explanation of symbols

(1) Pulley unit
(3) Rotating shaft
(5) Pulley
(7) Belt
(8) Belt slip detector
(11) Movable body
(13) Rotation sensor
(14) Processing means

Claims (1)

In a pulley unit comprising a pulley around which a belt is wound and a rotating shaft that rotates as the pulley rotates,
A movable body that can rotate relative to the pulley and that rotates together with the belt; a sensor that detects relative rotation of the movable body relative to the pulley; and a processing unit that generates a signal that reduces the load on the belt in accordance with a signal from the sensor. A pulley unit characterized by comprising.

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