JP2005282768A - Power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmission device which has a simpler structure in comparison with that using a one-way clutch provided in conventional examples, wherein a micro-variation in a rotation angular velocity can be efficiently absorbed. <P>SOLUTION: The power transmission device of a pulley unit or the like comprising a pulley 2 (outer annular body) and rotor shaft 3 (inner annular body) is constructed by mounting connectors 7 which connect the pulley 2 with the rotor shaft 3 in a plurality of positions at even intervals in the circumference of the pulley 2 and the rotor shaft 3. The connector 7 extends and contracts such as to permit a phase shifting between the pulley 2 and the rotor shaft 3 during transmitting a rotating power between the pulley 2 and rotor shaft 3 corresponding to variations in an input rotation angular velocity. <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 power of the engine is transmitted from the crankshaft to the accessory via the belt, the belt tends to slip due to minute fluctuations in the rotational angular velocity of the crankshaft, and noise tends to be generated. This will be described an alternator, which is one of the auxiliaries for example.

  In the crankshaft, the rotational angular velocity always fluctuates slightly due to the engine operation process. On the other hand, since the rotor of the alternator has a large rotational inertia, inertia torque is applied to the rotor. For this reason, the tension on the tension side and the loose side of the belt spanned between the rotor of the alternator and the crankshaft tends to fluctuate, and the belt slipping as described above may occur.

Therefore, as a conventional technique, there has been proposed a pulley unit in which a one-way clutch is incorporated between a pulley around which a belt is wound and a rotor shaft that is coupled to an alternator rotor so as to be integrally rotatable (for example, Patent Document 1). reference.). This pulley unit suppresses belt slippage and generates abnormal noise by the one-way clutch transmitting or shutting off the rotational power from the pulley to the rotor shaft in response to fluctuations in the rotational angular velocity of the crankshaft. This makes it possible to improve the durability of the belt.
JP 2001-90751 A

  The present invention provides a power transmission device such as a pulley unit that includes an outer ring body such as a pulley and an inner ring body such as a rotor shaft, and has a simpler configuration than the conventional example using the one-way clutch. It is an object to efficiently absorb minute fluctuations in angular velocity.

  The present invention is a power transmission device that transmits rotational power between an outer ring and an inner ring arranged concentrically with the outer ring, and a plurality of circumferentially equidistant intervals between the outer ring and the inner ring. A connecting member that connects the two rings is attached to the location, and each connecting member expands and contracts so as to allow a phase shift of both rings according to fluctuations in the angular velocity of the input rotation when transmitting rotational power between the rings. It is characterized by having been made.

  There are cases where the outer ring is on the rotational power input side and the inner ring is on the rotational power output side, and vice versa. The inner ring body may be hollow or solid.

  According to the present invention, for example, when the rotational angular velocity of the outer ring is slightly changed with the outer ring as the rotational power input side, when the rotational angular velocity increases, the inner ring and the outer ring are caused by the inertia torque of the inner ring. Since the body tends to rotate relative to the opposite direction, the connecting member is pulled and extended in the rotation direction. Thereby, since the phase shift between the outer ring and the inner ring is allowed and transmission of the rotational power from the outer ring to the inner ring is interrupted, the increase in the rotational angular velocity of the outer ring is absorbed. When the connecting member is pulled to a predetermined position, the outer ring and the inner ring are integrated to transmit the rotational power. On the other hand, when the rotation angular velocity of the outer ring decreases, the rotation force of the inner ring makes the rotation speed of the inner ring faster than the outer ring due to the inertial force of the inner ring, so that the connecting member rotates. Stretched in the direction. Thereby, since the phase shift between the outer ring and the inner ring is allowed and the transmission of the rotational power from the outer ring to the inner ring is blocked, the decrease in the rotational angular velocity of the outer ring is absorbed. In this way, minute fluctuations in the rotational angular velocity of the outer ring can be efficiently absorbed.

  In addition, according to the present invention, since the one-way clutch that has to be the complicated and expensive structure described in the conventional example is not used, a simple configuration in which only a plurality of connecting members are used is used. It is possible to reduce the component cost and manufacturing cost of the apparatus.

  Preferably, each said connection member can be arrange | positioned along the line extended in a radial direction from the rotation center of the said inner side ring body in the axial direction one end surface side of both said ring bodies. In this case, since the space occupied in the axial direction and the radial direction of the connecting member can be reduced, the power transmission device can be made compact in the axial direction and the radial direction.

  Preferably, at least one end of each connecting member can be hinged to the one axial end surface of the one ring body via a pin. In this case, when the connecting member expands and contracts, the attachment portions of the connecting member with respect to the both rings are not twisted, so that the durability of the connecting member is improved.

  Preferably, the connecting members on the outer ring side of the connecting members are shifted to one side in the circumferential direction so that the connecting members can be inclined at a predetermined angle with respect to the line extending in the radial direction. In this case, since the entire length of each connecting member is easily expanded and contracted, the phase shift between both rings can be facilitated and the allowable phase shift angle can be increased, and the absorption of rotational fluctuation is improved.

  According to the present invention, in a power transmission device such as a pulley unit including an outer ring body such as a pulley and an inner ring body such as a rotor shaft, both of the power transmission devices are simpler than a conventional example using a one-way clutch. When power is transmitted between the rings, the minute fluctuations in the rotational angular velocity can be efficiently absorbed.

  The best mode for carrying out the present invention will be described below with reference to the drawings. In this embodiment, a pulley unit is taken as an example of a power transmission device.

  Referring to FIGS. 1 and 2, a pulley unit 1 includes a pulley 2 as an outer ring body and an inner ring that is arranged concentrically on the inner peripheral side of the pulley 2 and transmits rotational power between the pulley 2. A rotor shaft 3 as a body, and a rolling bearing 4 disposed in the middle in the axial direction between the pulley 2 and the rotor shaft 3 are provided. The rolling bearing 4 is a lubricant-sealed deep groove ball bearing.

  A wave-like groove for winding the belt 6 is formed on the outer peripheral surface of the pulley 2. To the inner periphery of the rotor shaft 3, for example, a rotating shaft of an auxiliary machine provided in an automobile and a crankshaft of an engine are coupled so as to be integrally rotatable.

  Connecting members 7 for connecting the pulley 2 and the rotor shaft 3 are attached to a plurality of locations (four locations in the figure) at equal intervals in the circumferential direction on the one end surface side in the axial direction of the pulley 2 and the rotor shaft 3.

  Each connecting member 7 is formed in a band plate shape, and its outer end 7a and inner end 7b are formed to bulge out in a round shape. Each connecting member 7 is arranged along a line 10 extending radially from the rotation center O of the rotor shaft 3, and an outer end 7 a of each connecting member 7 is connected to the pulley 2 via a pin 8 and an inner end. 7 b is hinged to the rotor shaft 3 via pins 9. Each connecting member 7 expands and contracts in the longitudinal direction while inclining in one of the forward and reverse directions of the rotation direction according to a minute increase / decrease in the input rotation when transmitting the rotational power between the pulley 2 and the rotor shaft 3. Therefore, the phase shift between the pulley 2 and the rotor shaft 3 is allowed. That is, the connecting member 7 is formed of an appropriate material that can be expanded and contracted in the longitudinal direction.

  The operation of the pulley unit 1 will be described with reference to FIGS. 3 and 4.

  Here, a case where the pulley unit 1 is used as, for example, an alternator of an automobile will be described as an example. The alternator is an AC generator that is driven by a belt 6 from an engine of an automobile vehicle, and is constituted by a rotor, a stator, a regulator, a rectifier, and the like (not shown).

  The rotor shaft 3 is attached to the rotor of the alternator, and the pulley 2 is rotationally driven by a belt 6 that is rotationally driven by the crankshaft of the engine. In this example, the pulley 2 is the rotational power input side, and the rotor shaft 3 is the rotational power output side. In general, since the rotational speed of the crankshaft slightly fluctuates at a predetermined cycle, the rotational angular velocity of the pulley 2 that is rotationally driven from the crankshaft through the belt 6 fluctuates slightly in accordance with the predetermined cycle. Therefore, in this embodiment, the minute fluctuations in the rotational angular velocity of the pulley 2 can be efficiently absorbed. This will be described below.

  When the rotational angular velocity of the pulley 2 increases, the rotor shaft 3 and the pulley 2 tend to rotate relative to each other in the opposite direction due to the inertia torque of the rotor shaft 3, so that as shown by the arrow direction in FIG. The end 7a side is pulled in the rotation direction, and each connecting member 7 extends in the longitudinal direction while tilting by a predetermined angle X in the rotation direction with the pin 9 on the inner end 7b side as a fulcrum. As a result, a phase shift between the pulley 2 and the rotor shaft 3 is allowed and transmission of rotational power from the pulley 2 to the rotor shaft 3 is interrupted, so that an increase in the rotational angular velocity of the pulley 2 is absorbed.

  On the other hand, when the rotational angular speed of the pulley 2 decreases, the rotational inertial force of the rotor shaft 3 causes the rotational speed of the rotor shaft 3 to become faster than the pulley 2 so as to overtake the pulley 2, so that the direction of the arrow in FIG. As described above, when the inner end 7b side of each connecting member 7 is pulled in the rotational direction, each connecting member 7 extends in the longitudinal direction while being inclined by a predetermined angle Y in the rotational direction with the pin 8 on the outer end 7a side as a fulcrum. As a result, a phase shift between the pulley 2 and the rotor shaft 3 is allowed and transmission of rotational power from the pulley 2 to the rotor shaft 3 is interrupted, so that a decrease in the rotational angular velocity of the pulley 2 is absorbed.

  In this way, minute fluctuations in the rotational angular velocity of the pulley 2 are efficiently absorbed. Here, the elongation of the connecting member 7 will be described. As shown in FIG. 5, when the pulley 2 is rotated by an angle θ with respect to the rotor shaft 3, the elongation δ of the connecting member 7 is expressed by the following equation.

上記式において、ｌは連結部材７の外端７ａを支持するピン８の中心から内輪７ｂを支持するピン９の中心までの長さ、ｒはロータ軸３の回転中心Ｏから連結部材７の内輪７ｂを支持するピン９の中心までの長さである。

In the above formula, l is the length from the center of the pin 8 that supports the outer end 7a of the connecting member 7 to the center of the pin 9 that supports the inner ring 7b, and r is the rotational center O of the rotor shaft 3 to the inner ring of the connecting member 7. This is the length to the center of the pin 9 that supports 7b.

  As described above, in the present embodiment, the fluctuation of the rotational angular velocity of the pulley 2 can be efficiently absorbed with a simple configuration in which the pulley 2 and the rotor shaft 3 are simply connected by the plurality of connecting members 7. Can do. As a result, the amount of tension fluctuation between the tension side and the slack side of the belt 6 wound around the pulley 2 can be reduced, so that the torque borne by the belt 6 can be reduced and abnormal noise caused by slipping of the belt 6 can be reduced. Occurrence can be prevented. Therefore, it is possible to provide the pulley unit 1 that is inexpensive and can improve the durability of the belt as compared with the conventional example using the one-way clutch.

  In addition, since only a plurality of connecting members 7 are attached to one end of the pulley unit 1 in the axial direction, the space occupied in the axial direction and the radial direction of the connecting member 7 can be reduced. There is also an effect that the axial direction and the radial direction can be made compact as compared with those using a directional clutch.

  Hereinafter, other embodiments and application examples of the present invention will be described.

  (1) As shown in FIG. 6, each connecting member 7 is inclined by a predetermined angle Z with respect to the line 10 extending in the radial direction by disposing the outer end 7 a of each connecting member 7 in one circumferential direction. You may be in posture. In this case, it is possible to vary the phase shift between the pulley 2 and the rotor shaft 3 with respect to the extension of each connecting member 7, and it is possible to easily adjust the rotational fluctuation absorbing performance.

  (2) The connecting member 7 can have a rod shape, and the cross-sectional shape is not particularly limited, such as a circle or a corner. In addition, for example, as shown in FIG. 7, each connecting member 7 can be a coil spring 11. Moreover, as shown in FIG. 8, the U-shaped bending part 7c can be provided in the middle of the longitudinal direction of each connection member 7 shown in FIG. In these cases, since the total length of each connecting member 7 is easily expanded and contracted, the phase shift between the pulley 2 and the rotor shaft 3 can be easily allowed, and the allowed phase shift angle θ can be increased, so that the rotational fluctuation can be absorbed. improves.

  (3) For example, the rotor shaft 3 can be the rotational power input side and the pulley 2 can be the rotational power output side. As an example, a configuration in which the pulley unit 1 is attached to the crankshaft is conceivable. The operation in this case is basically the same as in the above embodiment.

  (4) Although not shown, the number of the connecting members 7 can be at least two and can be arranged at equal intervals around the circumference. Although not shown, each connecting member 7 can be provided not only on one end surface side in the axial direction of the pulley 2 and the rotor shaft 3 but also on the other end surface side. Further, the connecting member 7 can be formed of a material that can bend elastically while ensuring a predetermined strength, for example, an appropriate metal, rubber, resin, coil spring, or the like.

Sectional drawing which follows the axial direction of the pulley unit which concerns on embodiment of this invention Front view of FIG. Sectional view used to explain the operation when the rotational angular velocity of the pulley unit increases Sectional view used to explain the operation when the rotational angular velocity of the pulley unit decreases The figure for demonstrating elongation of the connection member shown in FIG. The figure corresponding to FIG. 2 with the pulley unit which concerns on other embodiment of this invention. The figure corresponding to FIG. 2 with the pulley unit which concerns on other embodiment of this invention. The figure corresponding to FIG. 2 with the pulley unit which concerns on other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Pulley unit 2 ... Pulley 3 ... Rotor shaft 4 ... Rolling bearing 7 ... Connecting member.

Claims (4)

A power transmission device for transmitting rotational power between an outer ring and an inner ring arranged concentrically therewith,
Attach connecting members that connect both rings to multiple locations at equal intervals in the circumferential direction between the outer ring and the inner ring, and connect each connecting member to the angular velocity of the input rotation when transmitting rotational power between the rings. A power transmission device that expands and contracts so as to allow a phase shift between both rings according to a change.   2. The power transmission device according to claim 1, wherein the connecting members are arranged along a line extending in a radial direction from a rotation center of the inner ring body on one end surface side in the axial direction of the two ring bodies. .   The power transmission device according to claim 2, wherein at least one end of each connecting member is hinge-coupled to an axial end surface of the one ring body via a pin.   4. The mounting member on the outer ring side of each connecting member is shifted to one side in the circumferential direction so that each connecting member is inclined at a predetermined angle with respect to a line extending in the radial direction. The power transmission device described in 1.

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