JP4196541B2 - Pulley unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pulley unit. This pulley unit is mounted on an auxiliary machine that is driven via a belt from a crankshaft of an engine such as an automobile. Examples of the auxiliary machine include an automobile alternator, an air conditioner compressor, a water pump, and a cooling fan.
[0002]
[Prior art]
In the conventional pulley unit, the pulley around which the belt is wound and the driven shaft are combined to absorb the rotational power input from the belt and prevent it from being transmitted to the driven shaft. Some rotor shafts have built-in one-way clutches.
[0003]
[Problems to be solved by the invention]
By the way, an alternator for an automobile is required to increase the speed and output high power. In order to do so, it is easy to increase the speed by reducing the pulley diameter, but in this case, it becomes difficult to incorporate the above-described one-way clutch.
[0004]
On the other hand, it has been conventionally considered that a one-way clutch for absorbing rotational fluctuation and a planetary speed increasing mechanism for increasing rotational power are incorporated in the pulley unit. In this case, the structure is complicated, and the one-way clutch and the planetary speed increasing mechanism are coaxially arranged adjacent to each other in the opposed annular space between the pulley and the rotor shaft arranged concentrically with each other. For this reason, the overall outer dimensions of the pulley unit are too large.
[0005]
In view of such circumstances, an object of the present invention is to provide a pulley unit having both a rotational fluctuation absorbing function and a speed increasing function of a pulley while keeping the outer dimensions compact.
[0006]
[Means for Solving the Problems]
The first pulley unit of the present invention transmits rotational power received from a belt to a driven shaft that is rotatably supported at a fixed position, and includes a pulley driven to rotate by the belt , Two pairs of eccentric rings, which are mounted via two rolling bearings at two circumferentially spaced locations and are integrally coupled in a state of maintaining a separation distance and having an eccentric hole at a position eccentric from the center; A rotor shaft coupled to the driven shaft so as to be capable of synchronous rotation and rotatably inserted into each eccentric hole of the pair of eccentric rings, and the pair of eccentrics on the inner circumference of the intermediate region in the axial direction of the pulley A one-way clutch disposed in a separated region of the ring, and the one-way clutch is formed integrally with a pulley or fitted and fixed to an inner peripheral surface of the pulley, and the outer ring The inner ring is inserted concentrically with the inner ring, and the inner ring and the pulley are interposed at several circumferential positions in the opposed annular space, and power transmission between the inner and outer rings is allowed according to the rotational speed difference between the inner and outer rings. And a state switching element for switching to a state or a shut-off state, wherein the rotor shaft is in rolling contact with a required angle region on the inner peripheral surface of the inner ring of the one-way clutch .
[0008]
According to a second pulley unit of the present invention, in the first configuration, an external gear meshes with the outer peripheral surface of the rotor shaft, and an inner gear inner surface of the one-way clutch meshes with the external gear of the rotor shaft. Each tooth gear is provided.
[0009]
According to a third pulley unit of the present invention, in the second configuration described above, the pulley and the inner ring of the one-way clutch are separated from each other by the ratio of the number of teeth of the internal gear of the inner ring and the number of teeth of the external gear of the rotor shaft. The speed increasing ratio of the rotational power transmitted to the rotor shaft is set.
[0010]
In short, in the present invention, the pulley and the rotor shaft eccentrically arranged with respect to the rotation center of the inner ring are brought into rolling contact with the required angle region of the inner ring of the one-way clutch arranged concentrically on the inner circumference of the pulley. Rotational power input to the rotor shaft is transmitted at an increased speed to the rotor shaft. With such a speed increasing structure, the configuration is simple and the outer dimensions are small compared to the structure using the planetary speed increasing mechanism of the conventional example.
[0011]
In addition, the fluctuation of the rotational power of the pulley includes a minute deceleration fluctuation and a minute acceleration fluctuation. First, the minute deceleration fluctuation is absorbed by the state switching of the one-way clutch arranged concentrically on the inner circumference of the pulley. On the other hand, the minute acceleration fluctuation is absorbed by the swing of the pulley and the one-way clutch with the rotation center of the rotor shaft as a fulcrum. Thereby, even if the input rotational power fluctuates, stable rotational power can be transmitted to the driven shaft.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The details of the present invention will be described based on embodiments shown in the drawings.
[0013]
1 to 5 show an embodiment of the present invention. 1 is a front view of the pulley unit, FIG. 2 is an arrow view of the section (2)-(2) in FIG. 1, and FIG. 3 is an arrow view of the section (3)-(3) in FIG. FIG. 4 is an exploded perspective view of the pulley unit, and FIG. 5 is a front view showing an operation for absorbing minute acceleration fluctuations of the pulley unit.
[0014]
The illustrated pulley unit includes a pulley 1, a pair of eccentric rings 2 and 3, a rotor shaft 4, and a one-way clutch 5.
[0015]
The pulley 1 is formed with a wave-like groove around which a V-rib-shaped belt 6 is wound, and for example, rotational power of a crankshaft of an automobile engine is transmitted through the belt 6.
[0016]
The pair of eccentric rings 2 and 3 are mounted on the inner peripheral surface of the pulley 1 at two locations separated in the axial direction via rolling bearings 7A and 7B, respectively. The pair of eccentric rings 2 and 3 have eccentric holes 2a and 3a, respectively, at positions eccentric to the center. These eccentric rings 2 and 3 are integrally coupled by a bolt 9 in a state where the eccentric rings 2 and 3 are arranged in parallel in the axial direction at a predetermined interval using a spacer 8.
[0017]
The rotor shaft 4 is rotatably inserted into the eccentric holes 2a and 3a of the pair of eccentric rings 2 and 3 via the two rolling bearings 10A and 10B. It is fixed to a driven shaft (for example, an alternator rotor) 11. An external gear 4 a is provided in the axial intermediate region on the outer peripheral surface of the rotor shaft 4.
[0018]
The one-way clutch 5 is interposed in the center in the axial direction on the inner peripheral surface of the pulley 1, and includes an inner ring 51, a synthetic resin annular cage 52, a plurality of rollers 53, and an elliptical coil spring 54 as an elastic member. , And two retaining rings 55 for positioning the rollers 53 in the axial direction. Here, the pulley 1 itself is used as an outer ring.
[0019]
The inner ring 51 is inserted concentrically into the inner periphery of the pulley 1, and flat key-like cam surfaces 51 a are provided at several places on the outer peripheral surface. In this example, there are eight cam surfaces 51a, and therefore the outer diameter shape of the inner ring 51 is an octagon. An inner gear 51 b that meshes with the outer gear 4 a of the rotor shaft 4 is provided on the inner peripheral surface of the inner ring 51.
[0020]
The annular cage 52 is disposed in the annular space facing the inner ring 51 and the pulley 1 and is externally positioned with respect to the inner ring 51 in the circumferential direction and the axial direction. In a region corresponding to the cam surface 51a of 51, a pocket 52a penetratingly formed inside and outside in the radial direction is provided. The annular retainer 52 is formed in a shape that fits and fits the polygonal outer peripheral surface shape of the inner ring 51 to prevent the annular retainer 52 from rotating in the circumferential direction with respect to the inner ring 51. Yes.
[0021]
One roller 53 is stored in each pocket 52a of the annular cage 52 in a state where the circumferential rolling range is restricted.
[0022]
The coil spring 54 is attached to a protrusion 52b projecting from the inner wall surface of each pocket 52a of the annular cage 52, and a wedge-shaped space that forms the roller 53 with the cam surface 51a and the inner peripheral surface of the pulley 1. It pushes to the narrow side (lock side).
[0023]
By the way, the pulley unit in this embodiment is input to the pulley 1 and the speed increasing structure for increasing the rotational power input to the pulley 1 from the crankshaft (not shown) via the belt 6 and transmitting it to the rotor shaft 4. It is characterized in that it is configured to have a rotational fluctuation absorbing structure that absorbs fluctuations in rotational power.
[0024]
Next, the operation of the pulley unit configured as described above will be described.
[0025]
First, in the process of increasing the rotational speed of the pulley 1, the roller 53 of the one-way clutch 5 is rolled to the narrow side of the wedge-shaped space to be locked, and the pulley 1 and the inner ring 51 of the one-way clutch 5 are integrated. And rotate synchronously. The pulley 1 and the inner ring 51 of the one-way clutch 5 rotate around the center of a pair of eccentric rings 2 and 3 rotatably supported on the outer periphery of the rotor shaft 4, and the inner ring 51 of the one-way clutch 5. As the motor rotates, the rotor shaft 4 is driven to rotate about its own center. As a result, the rotor shaft 4 is accelerated more than the rotational speed of the pulley 1 and the inner ring 51 of the one-way clutch 5. This speed increase ratio is determined by the ratio between the number of teeth of the internal gear 51b in the inner ring 51 of the one-way clutch 5 and the number of teeth of the external gear 4a in the rotor shaft 4, but the setting is arbitrary.
[0026]
On the other hand, in the process of decreasing the rotational speed of the pulley 1, the roller 53 of the one-way clutch 5 is rolled to the wide side of the wedge-shaped space to be in a free state, and transmission of rotational power from the pulley 1 to the rotor shaft 4 is interrupted. Thus, the rotor shaft 4 continues to rotate only with the rotary inertia force. At this time, although the inner ring 51 of the one-way clutch 5 is rotated by the rotation of the rotor shaft 4, the inner ring 51 rotates relative to the pulley 1.
[0027]
During rotation as described above, when the rotational speed of the pulley 1 fluctuates slightly, the roller 53 of the one-way clutch 5 is rolled to the wide side of the wedge-shaped space at that moment, As a result, the transmission of rotational power from the pulley 1 to the rotor shaft 4 is interrupted, and the rotor shaft 4 continues to rotate only by the rotational inertia force. Thereby, the minute deceleration fluctuation of the pulley 1 is absorbed.
[0028]
On the other hand, when the rotational speed of the pulley 1 fluctuates slightly, the tension on the tension side of the belt 6 increases at that moment, so that the pulley 1, the one-way clutch 5 and the eccentric ring 2, as shown by the phantom line in FIG. 3 swings around the rotor shaft 4 by a required angle with the rotation center of the rotor shaft 4 as a fulcrum. Thereby, the minute acceleration fluctuation | variation of the pulley 1 is absorbed.
[0029]
In this way, a constant rotational power can be transmitted to the driven shaft 11 by absorbing the fluctuation of the rotational power input to the pulley 1.
[0030]
By the way, the pulley unit as described above can be used for, for example, an automobile alternator, an air conditioner compressor, a water pump, a cooling fan, and the like. If it is used for an alternator, the alternator can be rotated at a high speed, which is advantageous in increasing power generation efficiency.
[0031]
As described above, in this embodiment, a simple speed increasing structure in which the rotation center of the inner ring 51 of the pulley 1 and the one-way clutch 5 and the rotation center of the rotor shaft 4 are arranged eccentrically, and the inner periphery of the pulley 1 are arranged. Since a general one-way clutch 5 that is concentrically disposed on the shaft 1 and a simple rotational fluctuation absorbing structure that utilizes the swing motion of the pulley 1 due to the eccentric arrangement of the pulley 1 and the rotor shaft 4 are employed. Compared to a structure using a one-way clutch and a planetary speed increasing device as in the example, the configuration can be simplified and the cost can be reduced.
[0032]
In addition, this invention is not limited only to embodiment mentioned above, Various application and deformation | transformation can be considered.
[0033]
(1) In the above embodiment, the types of the rolling bearings 7A and 7B between the pulley 1 and the pair of eccentric rings 2 and 3 and the rolling bearings 10A and 10B between the eccentric rings 2 and 3 and the rotor shaft 4 are deep grooves. It is not limited to a ball bearing, but can be an angular ball bearing, a roller bearing or a tapered roller bearing.
[0034]
(2) Although the roller type is exemplified as the one-way clutch 5 in the above embodiment, a sprag type one-way clutch may be used, and details of the one-way clutch 5 in the above embodiment may be used. Various modifications can be considered for the configuration.
[0035]
【The invention's effect】
In the pulley unit according to the first to third aspects of the invention, a simple speed increasing structure in which the rotation center of the inner ring of the pulley and the one-way clutch and the rotation center of the rotor shaft are arranged eccentrically, and a concentric shape on the inner periphery of the pulley A simple one-way clutch that uses a swinging motion of the pulley by using a general one-way clutch that is arranged on the pulley and a pulley and a rotor shaft that are eccentrically arranged. Compared to a structure using a planetary gearbox and a planetary speed increasing device, the configuration can be simplified and the cost of the pulley unit can be reduced.
[0036]
In particular, as in the invention of claim 2 , if the rolling contact of the rotor shaft with the inner ring of the one-way clutch is engaged with the gear, the processing becomes easy and it is possible to contribute to the improvement of productivity.
[0037]
Further, as in the third aspect of the invention, if the speed increasing ratio is determined by the gear ratio on the premise of the configuration of the second aspect, the speed increasing ratio can be easily set. Design and manufacture are easy.
[Brief description of the drawings]
FIG. 1 is a front view showing a pulley unit according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line (2)-(2) in FIG. 3) An arrow view of the cross section of the line [FIG. 4] An exploded perspective view of the pulley unit. [FIG. 5] A front view showing an operation of absorbing a slight acceleration fluctuation of the pulley unit.
DESCRIPTION OF SYMBOLS 1 Pulley 2, 3 Eccentric ring 4 Rotor shaft 5 One-way clutch 6 Belt 51 One-way clutch inner ring 51a Inner-ring cam surface 52 One-way clutch cage 53 One-way clutch roller

Claims (3)

A pulley unit that transmits rotational power received from a belt to a driven shaft that is rotatably supported at a fixed position,
A pulley driven to rotate by the belt;
A pair of two bearings that are mounted at two locations on the inner periphery of the pulley in the axial direction via rolling bearings and are integrally coupled while maintaining a separation distance and having an eccentric hole at a position eccentric from the center. With an eccentric ring,
A rotor shaft in which the driven shaft is coupled so as to be capable of synchronous rotation and is rotatably inserted into each eccentric hole of a pair of eccentric rings;
A one-way clutch disposed in the separation region of the pair of eccentric rings on the inner periphery of the intermediate axial region of the pulley;
The one-way clutch includes an outer ring formed integrally with the pulley or fitted and fixed to the inner peripheral surface of the pulley, an inner ring inserted concentrically with the outer ring, and an inner ring and a pulley. A state switching element that is interposed at several places in the circumference of the opposed annular space and that switches to a state in which power transmission between the inner and outer rings is allowed or cut off according to a difference in rotational speed between the inner and outer rings And
The pulley unit, wherein the rotor shaft is in rolling contact with a required angle region on an inner peripheral surface of an inner ring of the one-way clutch. The pulley unit of claim 1 ,
An outer gear is provided on the outer peripheral surface of the rotor shaft, and an inner gear that is engaged with the outer gear of the rotor shaft is provided on the inner peripheral surface of the inner ring of the one-way clutch. . The pulley unit according to claim 2 ,
The speed increasing ratio of the rotational power transmitted from the inner ring of the pulley and the one-way clutch to the rotor shaft is set by the ratio between the number of teeth of the inner gear of the inner ring and the number of teeth of the outer gear of the rotor shaft. A pulley unit characterized by that.

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