JP2005273743A - Power transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmission, which has superior reliability for a long period, capable of preventing noises generated from a belt and a pulley and improving its durability in a pulley unit. <P>SOLUTION: In the pulley unit 1, plate-shaped outer projected pieces 15 and 16 having radially inward flexibility on an inner periphery of the pulley 2 and plate-shaped inner projected pieces 17 and 18 having radially outward flexibility on an outer periphery of a rotor shaft 3 are formed so as to be alternately arranged at a circumferential direction respectively, and rubber bodies 19 to 22 are stored in housing spaces A1 to A4 between the outer projected pieces 15 and 16 and the inner projected pieces 17 and 18. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a power transmission device such as a pulley unit. This type of power transmission device can be installed in, for example, an engine crankshaft or accessories driven from the crankshaft via a belt. Examples of the auxiliary machines include an automobile alternator, an air conditioner compressor, a water pump, and a cooling fan.

  When the rotational driving force of the engine is transmitted from the crankshaft (driving side) to the auxiliary machine (driven side) via the belt, the belt slips due to minute fluctuations in the rotational angular velocity of the crankshaft, and noise is generated. Tend to occur. This will be described an alternator, which is one of the auxiliaries for example.

  If the engine as a drive source, the operation process of the engine crankshaft during its rotation, there is always a slight change of the rotational angular velocity. On the other hand, since the rotor of the alternator has a large rotational inertia (moment of inertia), inertia torque is applied to the rotor. For this reason, when the alternator rotor is driven by a crankshaft with minute fluctuations in the rotational angular velocity, the belt loosens and tension changes, causing tension fluctuations, while the belt is subjected to the inertia torque of the rotor. As a result, there is a tendency that the belt slips and noise is generated or the durability is lowered.

As a conventional technique, protrusions are provided at several circumferential positions on the inner peripheral surface of the pulley around which the belt is wound and the outer peripheral surface of the rotor shaft connected to the rotor of the alternator so as to be integrally rotatable. There has been proposed a power transmission device in which an elastic body such as a rubber or a spring is disposed in a space where projecting pieces are opposed in the circumferential direction (see, for example, Patent Document 1).
JP 2002-303333 A

  The present invention provides a power transmission device that is excellent in reliability over a long period of time by preventing occurrence of abnormal noise in the belt and improving durability.

  The present invention is a power transmission device that transmits rotational power between both inner and outer rings arranged concentrically, and has a flexible outer side that projects radially inwardly on the inner circumferential surface of the outer ring. The projecting pieces and flexible inner projecting pieces protruding radially outwardly on the outer circumferential surface of the inner ring body are alternately arranged in the circumferential direction, and the both projecting pieces are disposed between the opposed rings. An elastic body is stored in a storage space formed therebetween.

  In the above configuration, for example, when the outer ring becomes a driving ring and the angular velocity of the outer ring varies, the outer protruding piece approaches the inner protruding piece in the circumferential direction as the outer ring rotates. The outer projecting piece presses the elastic body against its elasticity and the elastic body is compressed between the outer projecting piece and the inner projecting piece, and the elastic body presses the inner projecting piece in the circumferential direction.

  In this case, as the outer protruding piece moves, the outer protruding piece bends slightly against the elasticity of the elastic body due to its flexibility. In this way, the elastic body is compressed and elastically deformed, and the outer protruding piece bends to absorb the increased fluctuation in the angular velocity of the outer ring body.

  When the angular velocity of the outer ring decreases and fluctuates, the inner protruding piece approaches the outer protruding piece as the inner ring rotates, and the inner protruding piece presses the elastic body against its elasticity, While being compressed between the outer protruding piece and the inner protruding piece, the elastic body presses the outer protruding piece in the circumferential direction.

  In this case, the inner protruding piece is slightly bent against the elasticity of the elastic body as it moves. In this way, the elastic body is compressed and elastically deformed, and the inner projecting piece is bent, so that the decrease fluctuation of the angular velocity of the outer ring body is absorbed.

  By the way, in this type of power transmission device, it has been necessary to reduce the elasticity (strength) of the elastic body so far in order to improve the damper performance. However, if an elastic body with low elasticity is used for this type of power transmission device, for example, if the outer ring body fluctuates in acceleration / deceleration, too much energy is accumulated in the elastic body, and the secular deterioration of the elastic body is accelerated. There was concern about the occurrence.

  On the other hand, in this invention, the structure which formed the protrusion which has flexibility in each of the inner peripheral surface of an outer ring body, and the outer peripheral surface of an inner ring body, and accommodated the elastic body in the storage space between protrusions Thus, for example, when there is an increase / decrease variation in the outer ring, not only the elastic body but also the protrusions that flex according to these movements, the energy associated with the increase / decrease variation in the outer ring Therefore, it is not necessary to reduce the elasticity of the elastic body. Or depending on the case, the elasticity (or spring constant) of the elastic body can be lowered as compared with the conventional case, and further improvement of the damper performance can be realized.

  In this way, the required damper performance can be obtained while the elasticity of the elastic body is ensured with a simple configuration in which the projecting pieces are formed on the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring. The service life of the entire device can be extended.

  In particular, when the power transmission device of the present invention is applied to, for example, a pulley unit, when a pulley as an outer ring is driven from the crankshaft side of the engine via a belt, for example, an inner ring via the spring and the damper is driven. As the rotor shaft rotates.

  The belt tension fluctuates, and the belt tension fluctuation is received by elastic deformation of the elastic body and the projecting piece in a situation where the rotor shaft cannot follow the tension fluctuation due to the inertia torque. The belt does not slip with respect to the pulley. As a result, the occurrence of abnormal noise between the belt and the pulley is suppressed or eliminated, and the durability of the belt is improved.

  According to the present invention, in a power transmission device that transmits the rotational driving force of an engine to an auxiliary machine such as an alternator via a belt from a crankshaft, for example, in a pulley unit, the generation or suppression of the generation of abnormal noise of the belt is improved. Thus, it is possible to provide a power transmission device with excellent reliability over a long period of time.

  The best mode of the present invention will be described below with reference to the drawings. In this embodiment, the power transmission device is applied to a pulley unit used for a vehicle auxiliary machine. FIG. 1 is a side sectional view showing the overall configuration of the pulley unit, and FIGS. 2 and 3 are front sectional views.

  A pulley unit 1 shown in these drawings includes a pulley 2 as an outer ring, and a rotor shaft 3 as an inner ring that is arranged on the inner peripheral side of the pulley 2 and transmits rotational power to and from the pulley 2. A power transmission medium member 4 that is arranged in the middle of the pulley 2 and the rotor shaft 3 in the axial direction to mediate power transmission from the pulley 2 to the rotor shaft 3, and the shaft of the pulley 2 and the rotor shaft 3. Rolling bearings 5 and 6 are provided between both ends in the direction.

  The rolling bearings 5 and 6 are interposed one by one on both sides in the axial direction of the annular space between the pulley 2 and the rotor shaft 3, and respectively hold an outer ring 7, an inner ring 8, a plurality of balls 9, and hold them. This is a general deep groove ball bearing comprising a crown-shaped cage 10 and a seal ring 11.

  On the outer peripheral surface of the pulley 2, a wavy groove 2 b for winding the belt V is formed. A plate-like drive-side first projecting piece 15 projecting inward in the radial direction as an outer projecting piece at several circumferential positions in the middle of the inner circumferential surface of the pulley 2, preferably at two positions facing each other at 180 °. , The drive side second projecting piece 16 is integrally formed. A radially inward flange 2a is provided on the other axial end of the inner periphery of the pulley 2 (corresponding to the free end of the rotor shaft 3).

  The inner peripheral surfaces 15c and 16c of the drive side first and second projecting pieces 15 and 16 are slidable or non-slidable on the outer peripheral surface 25 of the rotor shaft 3, and the circumferential side surface 15a of the drive side first projecting piece 15 is provided. 15b are formed parallel to each other along the radial direction, and the circumferential side surfaces 16a, 16b of the second projecting piece 16 are formed parallel to each other along the radial direction.

  The rotor shaft 3, for example the crankshaft axis of rotation and an engine auxiliary machine comprising a vehicle is integrally rotatably coupled. A driven side first projecting piece 17 projecting radially outward as an inner projecting piece is provided at several circumferential positions in the middle of the outer peripheral surface of the rotor shaft 3, preferably at two positions facing each other at 180 °. The second projecting pieces 18 are integrally formed.

  The driven side first and second projecting pieces 17 and 18 protrude radially outwardly from the outer peripheral surface of the rotor shaft 3 so as to be disposed between the driving side first and second projecting pieces 15 and 16, The first and second projecting pieces 17 and 18 and the drive-side first and second projecting pieces 15 and 16 are arranged alternately in the circumferential direction. The circumferential side surfaces 17a and 17b of the driven side first protrusion 17 are formed in parallel to each other along the radial direction. The circumferential side surfaces 18a and 18b of the second projecting piece 18 are formed in parallel to each other along the radial direction.

  In the opposed annular space between the pulley 2 and the rotor shaft 3, between the respective facing pieces 17, 18 on the rotor shaft 3 side and the respective protruding pieces 15, 16 on the pulley 2 side in the circumferential direction (four locations in the figure) Storage spaces A1, A2, A3, and A4 are formed between the two.

  The power transmission mediating member 4 is an elastic body housed in each of the drive side first and second projecting pieces 15 and 16, the driven side first and second projecting pieces 17 and 18, and the housing spaces A1, A2, A3 and A4. It is comprised from the rubber bodies 19, 20, 21, and 22 which are.

  In the pulley unit 1 configured as described above, when the belt V rotates with the rotation of a crankshaft (not shown), the pulley 2 is driven to rotate with the rotation. Then, the rotor shaft 3 is rotated by the power transmitted from the pulley 2 via the power transmission mediating member 4.

  Here, the process in which the pulley 2 rotates and the rotational power is transmitted to the rotor shaft 3 via the power transmission medium member 4 will be described in the case where the angular velocity of the pulley 2 increases and varies due to the pulsating rotation of the crankshaft. In this case, as indicated by the phantom line in FIG. 2, with the clockwise rotation of the pulley 2, the driving-side first protrusion 15 of the pulley 2 approaches the driven-side first protrusion 17 and the driving-side first protrusion The circumferential side surface 15a of the piece 15 presses the rubber body 19 against its elasticity, and the rubber body 19 is compressed between the circumferential side surface 15a and the opposing side surface 17b of the driven side first projecting piece 17, or The rubber body 19 presses the driven second protrusion 17 of the rotor shaft 3 in the circumferential direction. In this case, the first driving piece 15 on the driving side is slightly bent by the elasticity of the rubber body 19 due to its flexibility as it moves in the clockwise direction.

  On the other hand, the driving side second projecting piece 16 of the pulley 2 approaches the driven side second projecting piece 18, and the circumferential side surface 16a of the driving side second projecting piece 16 presses the rubber body 21 against its elasticity to rubber. The body 21 is compressed between the circumferential side surface 16a and the opposed side surface 18b of the driven second projection piece 18, and the rubber body 21 presses the driven second projection piece 18 of the rotor shaft 3 in the circumferential direction.

  In this case, the driving-side second projecting piece 16 is slightly bent by the elasticity of the rubber body 21 due to its flexibility as it moves in the clockwise direction.

  In this way, the rubber bodies 19 and 21 are compressed and elastically deformed, and the drive-side first projecting piece 15 and the drive-side second projecting piece 16 are bent to absorb the increased fluctuation in the angular velocity of the pulley 2. Thus, it is possible to prevent slippage and abnormal noise between the pulley 2 and the belt V.

  When the angular velocity of the pulley 2 decreases and fluctuates due to the pulsating rotation of the crankshaft, the driven-side first projecting piece 17 of the rotor shaft 3 moves along with the clockwise rotation of the rotor shaft 3 as shown by the phantom line in FIG. The circumferential side surface 17a of the driven side first projecting piece 17 approaches the driving side second projecting piece 16 and presses the rubber body 20 against its elasticity, so that the rubber body 20 is connected to the circumferential side surface 17a and the driving side second projecting piece 17. The rubber body 20 presses the drive-side second projecting piece 16 of the pulley 2 in the circumferential direction while being compressed between the opposing side surfaces 16 b of the projecting piece 16.

  In this case, the driven first projecting piece 17 is slightly bent by the elasticity of the rubber body 20 due to its flexibility as it moves in the clockwise direction.

  On the other hand, the driven-side second protrusion 18 of the rotor shaft 3 approaches the drive-side first protrusion 15 and the circumferential side surface 18a of the driven-side second protrusion 18 presses the rubber body 22 against its elasticity. While the rubber body 22 is compressed between the circumferential side surface 18a and the opposing side surface 15b of the driving side first projecting piece 15, the rubber body 22 presses the driving side first projecting piece 15 of the pulley 2 in the circumferential direction. In this case, the driven second projecting piece 18 is slightly bent by the elasticity of the rubber body 22 due to its flexibility as it moves in the clockwise direction.

  In this way, the rubber bodies 20 and 22 are compressed and elastically deformed, and the driven-side first projecting piece 17 and the driven-side second projecting piece 18 are bent to absorb the decrease variation of the angular velocity of the pulley 2. become.

  By the way, in this type of pulley unit, there are cases where convex portions protruding in the radial direction are formed on the inner peripheral surface of the pulley and the outer peripheral surface of the rotor shaft, and the rubber body is stored in the storage space between the convex portions. However, the conventional convex part is a rigid body, and even if the pulley is accelerated or decelerated, the convex part is not configured to bend. For this reason, if it is going to improve the damper performance of a pulley unit, it is necessary to reduce the elasticity (strength) of a rubber body. However, if a low-elasticity rubber body is used for this type of pulley unit, it is considered that when the pulley is fluctuated in acceleration / deceleration, too much energy is accumulated in the rubber body and the rubber body deteriorates over time. .

  Therefore, as in the embodiment of the present invention, the driving side first and second projecting pieces 15 and 16 having flexibility on the inner peripheral surface of the pulley 2 and the outer peripheral surface of the rotor shaft 3, respectively, The second projecting pieces 17 and 18 are formed, and the rubber bodies 19, 20, 21 and 22 are housed in the housing spaces A 1, A 2, A 3 and A 4 between the projecting pieces 15, 16, 17 and 18.

  With this configuration, not only the rubber bodies 19, 20, 21, and 22 but also the projecting pieces 15, 16, 17, and 18 that bend in accordance with these movements, the load of energy accompanying the speed increase / decrease fluctuation of the pulley 2. Therefore, it is not necessary to reduce the elasticity of the rubber bodies 19, 20, 21, 22.

  Accordingly, the elasticity of the rubber bodies 19, 20, 21, and 22 is maintained with a simple configuration in which the projecting pieces 15, 16, 17, and 18 are formed on the inner peripheral surface of the pulley 2 and the outer peripheral surface of the rotor shaft 3. The required damper performance can be obtained, and the service life of the entire pulley unit 1 can be extended. Furthermore, since the damper performance of the pulley unit 1 can prevent slippage and abnormal noise between the pulley 2 and the belt V, the durability of the belt V can be improved.

  In the above-described embodiment, the rubber bodies 19, 20, 21, and 22 are housed as elastic bodies in the housing spaces A1, A2, A3, and A4. However, the present invention is not limited to this, and the rubber bodies 19, 20, 21, and 22 are constructed. Instead of this, it is also possible to use a coil spring having the projecting pieces 15, 16, 17, 18 as spring seats. In this case as well, necessary damper performance can be obtained without reducing the elasticity (strength) of the coil spring, the service life of the entire pulley unit 1 can be extended, and slipping between the pulley 2 and the belt V can be prevented. The occurrence of abnormal noise can be prevented and the durability of the belt V can be improved.

Side surface sectional drawing which shows the whole structure of the pulley unit which concerns on the best form of this invention Front cross-sectional view of pulley unit showing the case of increasing fluctuation of pulley angular velocity Front cross-sectional view of pulley unit showing the case of decreasing fluctuation of pulley angular velocity

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pulley unit 2 Pulley 3 Rotor shaft 4 Power transmission mediating member 5,6 Rolling bearing 15 Drive side 1st protrusion 16 Drive side 2nd protrusion 17 Driven side 1st protrusion 18 Driven side 2nd protrusion 19-22 Rubber body

Claims (2)

  A power transmission device that transmits rotational power between both inner and outer rings arranged concentrically, and an outer protrusion having flexibility that protrudes radially inward on the inner peripheral surface of the outer ring, In addition, flexible inner protrusions projecting radially outward on the outer peripheral surface of the inner ring body are alternately arranged in the circumferential direction, and are formed between the both protrusion pieces between the two ring bodies facing each other. A power transmission device characterized in that an elastic body is stored in a storage space.   The outer ring is constituted by an alternator pulley having a belt winding part on the outer periphery and a belt for transmitting the rotational power of the engine is wound on the belt winding part, while the inner ring is formed by the pulley. The power transmission device according to claim 1, wherein the power transmission device is configured by an alternator rotor shaft disposed radially inward.

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