JP4289187B2 - Power transmission device - Google Patents

Description

  The present invention relates to a power transmission device such as a pulley unit, and more particularly to a power transmission device that can extract an output rotation with little fluctuation from an input rotation including fluctuation such as pulsation.

  Vehicles such as automobiles are equipped with auxiliary equipment such as an alternator, an air conditioner compressor, a water pump, and a cooling fan that are driven from a crankshaft of an engine via a belt. When the rotational power of the engine is transmitted from the crankshaft to the auxiliary machine via the belt, the belt tends to slip due to fluctuations in the rotational speed of the crankshaft, and abnormal noise tends to be generated.

  This will be explained by taking an alternator as one of the auxiliary machines as an example. Due to the operation process of the engine, the rotation speed of the crankshaft always varies during the rotation. 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, when the alternator rotor is driven by a crankshaft with fluctuations in rotational speed, the slack side and the tension side of the belt are alternately switched to generate a fluctuation in tension, while the inertia torque of the rotor is applied to the belt. As a result, the belt tends to slip and generate abnormal noise, or the durability tends to decrease.

  Therefore, conventionally, a power transmission device using a one-way clutch as a power transmission member between a rotor shaft of an alternator and a pulley around which the belt is wound has been proposed (see Patent Document 1).

  However, in the one-way clutch type power transmission device, the clutch locked state and the free state are repeated according to the fluctuation of the input rotation, and the non-transmission state is interposed between the transmission states. When switching from the free state to the locked state due to large rotational fluctuations on the input side, the rollers and sprags as the wedge members suddenly engage with each other, so relatively large fluctuations appear in the rotation on the output side, and the effect of absorbing rotational fluctuations Is insufficient.

For such a one-way clutch type power transmission device, a power transmission member is axially displaceable in a state where the power transmission member is fitted between the pulley and the rotor shaft in the rotational direction, and the transmission Spring-type power consisting of coil springs arranged on both sides of the body in the axial direction and configured to absorb the rotational fluctuation by displacing the transmission body in the axial direction against the spring force of the coil spring according to the fluctuation of the input rotation A transmission device has been proposed.
JP 2001-90751 A

  In the case of the spring-type power transmission device, the spring constant needs to be adjusted in order to set the pressing force of the coil spring that presses the transmission body in the axial direction to a required value. The spring constant of the coil spring is changed by changing the helical diameter of the coil spring. However, it is not always easy to change the spring constant of the coil spring. Further, in order to ensure the spring strength of the coil spring, it is necessary to increase the size of the coil spring, but it is difficult to ensure a space for accommodating the coil spring. In order to secure the space for accommodating the coil spring, it may be necessary to change the size of the pulley or the rotor shaft.

  A power transmission device according to the present invention is a power transmission device including two rotating bodies arranged to face radially inward and outward, and a power transmitting member disposed between both rotating bodies, the outer rotating body described above. Is provided with a first fitting portion that forms one of a spiral shape and a linear shape on the inner peripheral surface, and the inner rotating body has a second fit that forms the other shape of the spiral shape and the linear shape on the outer peripheral surface. The power transmission member includes a third fitting portion having a shape corresponding to the first fitting portion on the outer peripheral surface, and a fourth fit having a shape corresponding to the second fitting portion on the inner peripheral surface. It is characterized by comprising an annular transmission provided with a joint and a plurality of springs arranged in series or in parallel on both sides in the axial direction of the annular transmission.

  According to the above configuration, by changing the number of springs arranged on both sides in the axial direction, the manner of arrangement, etc., the spring constant of the whole spring is changed, and the annular transmission is easily pressed. The spring force can be set to a desired value.

  For example, in the case of disc springs, if they are arranged in parallel, that is, the conical surface of each disc spring is arranged so as to overlap the plate surface of another disc spring, the spring constant increases. When the disc springs are arranged in series, that is, the small diameter portions and the large diameter portions of adjacent disc springs are in contact with each other, the spring constant is reduced. Moreover, it is also possible to arrange by combining a parallel arrangement and a serial arrangement.

  When multiple disc springs are used side by side, it is possible to effectively utilize the narrow space in the axial direction, and slip occurs between the plate surfaces of the disc springs that overlap each other. It becomes resistance to the movement of the direction, and the attenuation effect of the rotation fluctuation is large.

  The above-mentioned spring is a corrugated annular spring made of a washer-like spring plate formed into a waveform in the circumferential direction, or a wave formed in a spiral shape with a washer-like spring plate in a spiral shape. A spiral spring may be used.

  When a plurality of corrugated annular springs are used, it is desirable that each corrugated annular spring is coupled to each other by welding or the like in a state where the corrugated convex portions face each other adjacent corrugated annular springs. In this configuration, the corrugated convex portion of one corrugated annular spring does not fit into the corrugated concave portion of the other corrugated annular spring, and a sufficiently wide expansion / contraction range of each corrugated annular spring can be secured.

  In addition, in a plurality of corrugated annular springs, by sandwiching a washer-shaped member between adjacent corrugated annular springs, the corrugated convex portion of one corrugated annular spring fits into the corrugated concave portion of another adjacent corrugated annular spring. May be prevented. When it is desired to increase the spring constant of the plurality of corrugated annular springs, the corrugated phases may be matched so that the corrugated plate surfaces of the corrugated annular springs are in contact with the corrugated plate surfaces of the adjacent corrugated annular springs. .

  Corrugated annular springs and corrugated spiral springs are relatively easy to manufacture, and even when an excessive load is applied from the annular transmission, the axially facing portions are in close contact with each other and deformed flatly. Therefore, there is no plastic deformation or damage.

  According to the present invention, the spring constant can be changed within a narrow space in the axial direction, and the force for pressing the annular transmission can be set to a required value without changing the size of the accommodation space.

  The best mode of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a sectional view of a half of the power transmission device according to the best embodiment, and FIG. It is a perspective view of the annular transmission which is a part of. The power transmission device is installed in an input unit of an alternator that is an auxiliary machine for an engine of an automobile or the like.

  Referring to these drawings, a pulley (drive-side rotator) 1 has a pulley groove 1a around which a belt (not shown) wound around an outer peripheral surface of the pulley (not shown) is wound. A spline (linear fitting portion as a first fitting portion) 1s having a linear shape in the axial direction is provided on the surface. The rotor shaft (driven rotor) 2 is disposed on the radially inner side of the pulley 1 and includes a helical spline (spiral fitting portion as a second fitting portion) 2n on the outer peripheral surface.

  The rolling bearing 3 is a deep groove ball bearing that supports the rotor shaft 2 on the pulley 1. The rolling bearing 3 is provided on the step portion 2 a on the outer peripheral surface of the rotor shaft 2, and is fixed in the axial direction by a retaining ring 2 b. The pulley 1 is positioned in the axial direction.

  The annular transmission body 4 is provided in an annular space 5 between the outer peripheral surface of the rotor shaft 2 and the inner peripheral surface of the pulley 1 in a state that can be displaced within a certain range in the axial direction, and is included in the input rotation to the pulley 1. The rotational power of the pulley 1 can be transmitted to the rotor shaft 2 while absorbing fluctuations such as pulsation.

  The annular transmission body 4 is provided with a spiral spline (spiral fitting portion as a third fitting portion) 4n spiraling in the axial direction corresponding to the helical spline 2n of the rotor shaft 2 on the inner peripheral surface. A straight spline (linear fitting portion as a fourth fitting portion) 4s that is linear in the axial direction corresponding to the linear spline 1s of the pulley 1 is provided on the surface.

  In the above configuration, in the present embodiment, the power transmission member is arranged in parallel on the annular transmission body 4 and on both sides in the axial direction of the annular transmission body 4 and presses the annular transmission body 4 in the axial direction. It comprises springs 6 and 7.

  The disc spring 6 on one side in the axial direction (left side in FIG. 1) has a truncated cone shape having a conical convex plate surface 6a and a conical concave plate surface 6b, and each conical convex plate surface 6a serves as the annular transmission 4. Further, the conical convex plate surface 6a and the conical concave plate surface 6b are arranged in parallel so as to extend outward in the axial direction. The outer ends of these disc springs 6 are received by spring receivers 8 that are in contact with the inner diameter edge 1 b of the pulley 1.

  The disc spring 7 on the other side in the axial direction (the right side in FIG. 1) has a conical convex plate surface 7 a and a conical concave plate surface 7 b, each having a truncated cone shape, and each conical convex plate surface 7 a from the annular transmission 4. Also, the conical convex plate surface 7a and the conical concave plate surface 7b are arranged in parallel so as to face outward in the axial direction. These disc springs 7 are received by spring receivers 9 that are in contact with the inner ring of the rolling bearing 3.

  Grease is applied to each of the linear splines 1s, 4s and the spiral splines 2n, 4n, which are sliding portions between the annular transmission 4 and the pulley 1 or the rotor shaft 2, or for friction reduction such as fluorine coating. Coating is applied. A seal 10 is provided on the inner diameter edge 1 b of the pulley 1 to seal the space between the pulley 1 and the rotor shaft 2.

  In the above configuration, the rotational power of the pulley 1 is such that the linear spline 1 s of the pulley 1 and the linear spline 4 s of the annular transmission 4 are fitted, and the helical spline 4 n of the annular transmission 4 and the helical spline of the rotor shaft 2. It is transmitted to the rotor shaft 2 by 2n fitting.

  When the pulley 1 is rotating normally, the annular transmission 4 is positioned in the middle in the axial direction shown in FIG. 1, but the pulley 1 suddenly fluctuates in speed toward the front side indicated by the arrow a in FIG. Then, the annular transmission 4 tries to follow the rotation of the pulley 1 and resists the spring force of the disc spring 6 on one axial side, and the helical spline n of the annular transmission 4 and the helical spline 2n of the rotor shaft 2. Is displaced in the axial direction (to the left in FIG. 1) along the fitting surface.

  Then, while the annular transmission 4 is displaced in one axial direction, a delay occurs in the rotation of the rotor shaft 2 with respect to the pulley 1. I don't get it. In short, the rotational fluctuation included in the input rotation is absorbed as energy for displacing the annular transmission 4 in the axial direction. Therefore, the action of a sudden tension on the belt due to the rotation fluctuation can be prevented, and the life of the belt and the pulley 1 can be extended.

In the above case, since the disc springs 6 and 7 are arranged in parallel, the overall spring constant k is such that the number of the disc springs 6 and 7 is n, the axial load is P, and the deflection amount is δ.
k = n (P / δ) (1)
Thus, even if the value is large and the load acting on the disc spring 6 (or 7) from the annular transmission body 4 is large, it is possible to cope with this with a large repulsive force.

  When the plurality of disc springs 6 and 7 are compressed and deformed, slip occurs between the plate surfaces 6a and 6b of the disc springs 6 and 7 that overlap each other. The friction caused by this slip becomes resistance to the axial movement of the annular transmission 4 and enhances the effect of damping the rotational fluctuation.

When the load acting on the disc spring 6 (or 7) from the annular transmission 4 is small, the disc springs 6 and 7 are connected in series, that is, the conical convex plate surface 6a (small diameter portion) of the adjacent disc springs 6 and 7. What is necessary is just to lower | hang the whole spring constant by arranging so that the conical concave plate surface 6b (large diameter part) may contact | connect. The spring constant k in the case of series is
k = (1 / n) · (P / δ) (2)
Thus, the value is significantly smaller than that in the parallel case.

  The plurality of disc springs 6 and 7 may be arranged by combining a parallel arrangement method and a serial arrangement method. In this case, the spring constant is intermediate between the spring constant when all of the plurality of disc springs 6 and 7 are arranged in parallel and the spring constant when all of the plurality of disc springs 6 and 7 are arranged in series. Value.

  When the rotation of the pulley 1 suddenly fluctuates in the deceleration direction (the direction indicated by the arrow B in FIG. 1), the annular transmission 4 tries to follow the rotation of the pulley 1 and resists the spring force of the disc spring 7 to rotate the rotor. It moves in the deceleration direction B along the fitting surface between the spiral spline 2n of the shaft 2 and the spiral spline 4n of the annular transmission 4, and is displaced in the other axial direction (rightward in FIG. 1). Absorbs fluctuations included in one rotation.

  The spring that presses the annular transmission body 4 in the axial direction is not limited to the disc springs 6 and 7, and other types of springs made of a spring plate material can be used as shown in FIGS. 3 to 5. FIG. 3 is a side view of a main part of a power transmission device according to another embodiment of the present invention, showing a half part in cross section. FIG. 4 is a perspective view showing a single spring used in the main part of FIG.

  In the form shown in FIG. 3, a plurality of corrugated annular springs 11 and 12 are provided on both sides in the axial direction of the annular transmission 4. As shown in FIG. 4, the corrugated annular springs 11 and 12 are formed by forming a washer-like spring plate into a corrugated shape along the circumferential direction. The corrugated annular springs 11 and 12 are arranged along the circumferential direction. Corrugated convex portions 11a and 12a projecting to the one side in the axial direction and corrugated convex portions 11b and 12b projecting to the other axial direction are provided for each fixed angle.

  The plurality of corrugated annular springs 11 (or 12) are axially juxtaposed on both sides in the axial direction of the annular transmission 4, and are adjacent to the other corrugated annular springs 11 (or 12) and corrugated convex portions 11a, 11b (or 12b). 12a) are connected to each other, for example, by welding. In FIG. 3, the code | symbol 13 has shown the connection part of waveform convex part 11a, 11b (or 12b, 12a).

  In the form shown in FIG. 3, when the annular transmission 4 is displaced in one axial direction, the undulating annular spring 11 (or 12) on the displacement side is compressed into a flat shape in the axial direction. When an excessive load is applied from the annular transmission 4, they are brought into close contact with each other and deformed into a flat shape so that they are not plastically deformed or damaged. For example, the corrugated annular springs 11 and 12 may be formed by punching a flat spring plate material into a washer shape and then forming the washer-shaped spring plate material into a waveform along the circumferential direction by a press or the like. Can be manufactured easily.

  A corrugated spiral spring 14 as shown in FIG. 5 may be provided on both sides of the annular transmission 4 in the axial direction. The corrugated spiral spring 14 is formed by continuously forming a washer-like spring plate material in a spiral shape, and is formed into a corrugated shape along the spiral direction. It has a corrugated convex portion 14a that projects and a corrugated convex portion 14b that projects to the other side in the axial direction. In the corrugated spiral spring 14, it is desirable that the corrugated convex portions 14 a and 14 b of each spiral winding portion are in a state of abutting against the corrugated convex portions 14 a and 14 b of other spiral winding portions adjacent to each other.

  The wave helical spring 14 can adjust the force of pressing the annular transmission 4 almost steplessly by changing its helical length. Further, since the corrugated spiral spring 14 is continuous in a spiral shape, the corrugated spiral spring 14 is not scattered during the assembly process and is easy to handle. When an excessive load is applied from the annular transmission 4, the spirally wound portions are brought into close contact with each other and deformed into a flat shape without causing plastic deformation or damage. In manufacturing, for example, after punching a flat spring plate material into a washer shape, a plurality of washer-shaped spring plate materials are connected to each other in a spiral shape, and the spiral spring plate material is moved along the spiral direction. What is necessary is just to shape | mold into a waveform and a troublesome process is not required.

  1 and 2, the annular transmission body 4 is fitted with the inner peripheral rotor shaft 2 by a linear spline along the axial direction, and the outer peripheral pulley 2 and May be fitted with a helical spline. The annular transmission 4 is fitted to the rotor shaft 2 by a helical spline 4n, and the pulley 1 is fitted to the helical spline 4n to the rotor shaft 2 by a helical spline in the reverse screw direction. Good. Furthermore, instead of the spiral spline provided between the annular transmission body 4 and the rotor shaft 2 or between the annular transmission body 4 and the pulley 1, it may be fitted with a screw having a large lead angle. In short, it is sufficient that at least one of the outer diameter side rotating body and the inner diameter side rotating body is fitted to the annular transmission body 4 by the helical fitting portion.

Sectional drawing of the half part of the power transmission device which concerns on the best form of this invention. The perspective view of the annular transmission body which is a part of apparatus of FIG. In the side view of the principal part of the power transmission device which concerns on the other form of this invention, the half part is shown in cross section. The perspective view of the spring used for the principal part of FIG. The perspective view of the spring used for the further another form of this invention.

Explanation of symbols

1 Pulley (drive-side rotating body)
1s spline (linear fitting part)
2 Rotor shaft (driven rotor)
2n Spiral spline (spiral fitting part)
4 annular transmission 4s spline (linear fitting part)
4n Spiral spline (spiral fitting part)
5 annular space 6, 7 disc spring 11, 12 corrugated annular spring 14 corrugated spiral spring

Claims (3)

A power transmission device comprising two rotating bodies arranged opposite to each other on the radially inner side and the outer side, and a power transmission member arranged between both rotating bodies,
The outer rotating body includes a first fitting portion having one of a spiral shape and a linear shape on the inner peripheral surface, and the inner rotating body has a spiral shape and a linear shape on the outer peripheral surface. A second fitting portion having the other shape;
The power transmission member includes a third fitting portion having a shape corresponding to the first fitting portion on an outer peripheral surface and a fourth fitting portion having a shape corresponding to the second fitting portion on an inner peripheral surface. And a plurality of springs arranged in series or in parallel on both sides in the axial direction of the annular transmission.   The said spring is a wave-like annular spring which consists of a washer-like spring board shape | molded by the waveform in the circumferential direction, and it has arrange | positioned two or more by the axial direction both sides of the said annular transmission body, It is characterized by the above-mentioned. Power transmission device.   The spring is a wave spiral spring formed in a spiral shape with a washer-like spring plate material in a spiral shape, and a plurality of springs are arranged on both sides in the axial direction of the annular transmission body. The power transmission device according to claim 1.

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