JP2003278788A - Power transmission mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmission mechanism excellent in reliability and durability by stabilizing a force with which a plate spring is pressed into contact with the curved recess part of a hub. <P>SOLUTION: The power transmission mechanism has a pulley, a shaft disposed concentric with the pulley, and the hub secured to the shaft. A pair of plate spring mounting parts for engaging the ends of the plate spring is provided on the inner peripheral surface of the pulley, and the curved recess part with which the plate spring is pressed into contact is provided on the outer peripheral surface of the hub. The center portion of the plate spring is deflected and pressed into contact with the curved recess part of the hub to transmit motive power from the pulley to the hub. The mounting part side engaging surface of the plate spring mounting part for engaging the plate spring and a plate spring side engaging surface at the end of the plate spring for engaging the engaging surface of the mounting part are formed as substantially cylindrical surfaces. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission mechanism having a function as a torque limiter, and more particularly to a power transmission mechanism most suitable for use in a compressor of an air conditioner for a vehicle such as an automobile among compressors.

[0002]

2. Description of the Related Art Conventionally, as a power transmission mechanism having a function as a torque limiter, for example, a leaf spring fixed to a shaft of a compressor and a drive lever provided on an inner peripheral side of a pulley are connected by a rivet. , Proposal to protect the compressor by cutting off the rivet when excessive torque is applied to the shaft to cut off power transmission to the shaft (Japanese Utility Model Laid-Open No. 63-142460), or compression The rotation transmission plate provided on the shaft of the machine and the side surface of the pulley are connected via a load breaking material,
When excessive torque is applied to the shaft, it has been proposed that the load breaking material is broken to cut off the power transmission to the shaft to protect the compressor (for example, Japanese Utility Model Publication No. 6-39105). ).

However, in the proposal disclosed in Japanese Utility Model Laid-Open No. 63-142460, an increase in the number of parts may cause an increase in cost and the mechanism becomes complicated. Further, if the drive lever is provided on the inner peripheral side of the pulley, the pulley diameter may be increased, and the compressor may be increased in size. On the other hand, in the proposal disclosed in Japanese Utility Model Publication No. 6-39105, since the repeated stress is applied to the breaking member, the breaking member may change over time, and the breaking member may be broken under a torque load of a predetermined value or less, The reliability of the power transmission mechanism may be reduced.

In order to solve the problems of the conventional power transmission mechanism, the present applicant has previously made a pair of leaf spring mounting portions 102 provided on the inner peripheral surface side of the pulley 101 as shown in FIG. The end portion of the leaf spring 103 is engaged with the plate spring 103, the center of the leaf spring is bent, and the curved concave portion 104 is provided on the outer peripheral surface of the hub.
The pulley 101 is pressed against the hub 105 to transmit power to the hub 105, and when an excessive torque acts on the shaft, a phase shift occurs between the hub and the pulley and the end of the curved recess 104 of the hub causes the leaf spring 103 to move. It has been proposed that the hub 105 and the pulley 101 can be disconnected by bending the pulley 105 toward the pulley side to cut off power transmission (Japanese Patent Laid-Open No. 2000-249160). According to the previous proposal by the applicant, it is possible to realize a power transmission mechanism having excellent reliability while achieving simplification of the structure and cost reduction.

[0005]

However, there is room for further improvement in the previous proposal by the applicant. In other words, in the previous proposal by the applicant, the end portion of the leaf spring is engaged with the substantially V-shaped notch 106 provided in the leaf spring mounting portion 102, but the leaf spring is used during torque transmission. The end portion of the spring 103 may vibrate slightly. When such a slight vibration is applied, the end of the leaf spring 103 and the notch 106 of the leaf spring mounting portion 102 may be welded or worn. Further, rust may occur at the end of the leaf spring 103 and the notch 106. If the above welding, wear, rust, etc. occur, the durability of the device may be reduced. In addition, the curved concave portion 104 of the hub 105
There is a possibility that variations may occur in the breaking torque that is pressed against the.

The object of the present invention is based on the previous proposal by the present applicant, which has solved the problems of the conventional power transmission mechanism as described above, and the welding and wear of the end portion of the leaf spring and the leaf spring mounting portion It is to provide a power transmission mechanism capable of preventing rust and improving durability and reliability.

[0007]

In order to solve the above problems, a power transmission mechanism of the present invention has a pulley, a shaft arranged concentrically with the pulley, and a hub fixed to the shaft. A pair of leaf spring mounting portions that engage with end portions of the leaf springs on the inner peripheral surface of the pulley, and curved concave portions on the outer peripheral surface of the hub where the leaf springs are in pressure contact, and the central portion of the leaf springs is provided. In a power transmission mechanism in which power is transmitted from a pulley to a hub by being bent and brought into pressure contact with a curved concave portion of a hub, an attachment portion side engagement surface with which a leaf spring of the leaf spring attachment portion is engaged, and the engagement It is characterized in that the leaf spring side engaging surface of the leaf spring end engaged with the surface is formed as a substantially cylindrical surface.

The leaf spring side engagement surface can be formed from an outer surface of a cylindrical portion provided at an end portion of the leaf spring. The cylindrical portion can be provided by joining a separate cylindrical member to the end portion of the leaf spring, but can also be provided integrally with the end portion of the leaf spring. If the cylindrical portion is integrally provided at the end of the leaf spring, the increase in the number of parts can be prevented.

It is preferable to interpose a surface layer different from that of the leaf spring or the attachment portion between the leaf spring side engagement surface and the attachment portion side engagement surface. Such a surface layer can be provided on the engaging surface on the leaf spring side and / or on the engaging surface on the mounting portion side.

The surface layer can be formed of, for example, a resin layer. The resin forming the resin layer is not particularly limited, but it is preferable to use a resin having a good slip property and a low friction coefficient, for example, a fluorine resin.

The surface layer can also be formed as a nitriding layer. The nitriding method is not particularly limited, but a salt bath nitriding treatment such as sulphidizing nitriding treatment can be applied.

The power transmission mechanism according to the present invention can be utilized in a wide range of industrial fields, and is most suitable for a compressor, for example, a compressor of a vehicle (automobile) air conditioner.

In the power transmission mechanism as described above, both the mounting portion side engagement surface and the leaf spring side engagement surface are formed of substantially cylindrical surfaces, so that the slipperiness of both engagement surfaces is improved. it can. Therefore, even if slight vibration occurs in the leaf spring during torque transmission, welding and wear of both engaging surfaces are reliably prevented, fluctuations in the pressure contact force of the leaf spring to the curved recess are prevented, and the cutoff torque is maintained constant. Therefore, it is possible to realize a power transmission mechanism having excellent durability and reliability. Further, if a different surface layer is interposed between the mounting portion side engagement surface and the leaf spring side engagement surface, welding and wear can be prevented more effectively, and
It can prevent the generation of rust.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the power transmission mechanism of the present invention will be described below with reference to the drawings. Further, in the following embodiments, a case where the power transmission mechanism is applied to a compressor (for example, a swash plate type compressor used in an air conditioner for an automobile) will be described. 1 to 5
FIG. 3 shows a power transmission mechanism according to an embodiment of the present invention. In the figure, 1 indicates a power transmission mechanism. The power transmission mechanism 1 is attached to the housing 2 of the compressor. The inner ring of the ball bearing 3 is fixed to the housing 2. A pulley 4 is fixed to the outer ring of the ball bearing 3. A small diameter portion 8 of a shaft 7 of the compressor, which is arranged concentrically with the pulley 4, is fitted in the central portion 6 of the hub 5. And
The shaft is fixed to the hub 5 by screwing the nut 10 into the thread groove formed on the end of the shaft 7.

On the inner peripheral surface of the pulley 4, more specifically, on the inner peripheral surface of the rim 11 of the pulley 4, a pair of leaf spring mounting portions 14 for fixing the end portions 13 of the leaf springs 12 are arranged at equal intervals. It is provided in pairs. The leaf spring mounting portion 14 has an end portion 13 of the leaf spring 12.
Mounting portion side engaging surface 1 with which the cylindrical portion 20 provided on the
5 are provided. A leaf spring side engagement surface 21 formed as an outer peripheral surface of the cylindrical portion 20 is engaged with the engagement surface 15. That is, the engagement surface 21 is formed as a cylindrical surface, and the engagement surface 15 with which the cylindrical portion 20 having the engagement surface 21 is engaged is also formed as a cylindrical surface. That is, in this embodiment, the mounting portion side engagement surface 15 and the leaf spring side engagement surface 21 are formed as substantially cylindrical surfaces. In addition,
In the present embodiment, the leaf spring 12 and the cylindrical portion 20 are composed of separate members, but the cylindrical portion 20 may be provided integrally with the end portion 13 of the leaf spring 12.

Between the engagement surface 15 and the engagement surface 21,
Pulley 4 in which the cylindrical portion 20 and the mounting portion 14 are integrally formed
And surface layers 22 and 23 different from the above are interposed. In this embodiment, as shown in FIG. 5, the surface layer 22 is formed on the engagement surface 15, and the surface layer 23 is formed on the engagement surface 21. The surface layers 22 and 23 are resin layers made of fluorine resin. In this embodiment, the surface layers 22 and 23 are formed on both the engaging surfaces 15 and 21, but the surface layer may be formed only on one of the engaging surfaces.

On the outer peripheral surface of the rim 16 of the hub 5, a curved concave portion 17 that curves toward the inside of the hub 5 is provided corresponding to the leaf spring 12. An elastic member 19 made of rubber or low-rigidity resin is provided between the rim 16 and a circumferential wall 18 provided inside the rim 16. The elastic member 19 absorbs a slight vibration of the rim 16 when the hub 5 rotates. However, the elastic member 1
9. The wall 18 can be omitted. Even if the elastic member 19 and the like are omitted, the object of the present invention can be achieved and the same operation and effect can be achieved.

In the present embodiment, the leaf spring mounting portion 14
When the cylindrical portion 20 of the end portion 13 of the leaf spring 12 is engaged with the engaging surface 15 of the and the central portion of the spring 12 is bent toward the hub 5 side,
The cylindrical portion 20 rotates along the engaging surface 15 so that the surface 12a of the spring 12 is pressed against the surface 17a of the curved concave portion 17, and the pulley 4
The driving force from the shaft is transmitted to the shaft 7 via the hub 5.

In this embodiment, for example, when some abnormality occurs in the compressor and a torque exceeding the set value is applied to the hub 5, the pulley 4 and the hub 5 are out of phase with each other, and the end of the curved recess 17 is a plate. As shown in FIG. 3, the leaf spring 12 comes into contact with the spring 12, the deflection direction is reversed from the curved recess 17 side to the inner peripheral surface side of the pulley 4, the connection between the pulley 4 and the hub 5 is released, and the power is cut off. It Therefore, the compressor is protected because no more excessive load is applied to the compressor. Further, when a trouble such as seizure occurs in the compressor and the compressor is locked, belt damage due to slip of the vehicle-side drive belt can be prevented. After repairing the abnormal portion, the leaf spring 12 can be easily returned to the connected state by aligning the phases of the pulley 4 and the hub 5 and bending the leaf spring 12 toward the curved recess 17 side.

Further, in the present embodiment, the leaf spring 12
Plate spring side engaging surface 21 and the attaching portion side engaging surface 1 of the attaching portion 14.
Since 5 is substantially formed of a cylindrical surface, the slipperiness between both engaging surfaces can be greatly improved. Therefore, the leaf spring 1
The friction between the leaf spring 12 and the mounting portion 14 when the 2 is bent toward the curved recess 17 side or the anti-curved recess side can be significantly reduced. Further, as a result of the frictional resistance between the engagement surface 15 and the engagement surface 21 being significantly reduced, even if the leaf spring 12 vibrates during torque transmission, welding and wear of the engagement surface 15 and the engagement surface 21 can be prevented. . Therefore, it is possible to prevent the pressure contact force of the leaf spring 12 from being applied to the curved concave portion 17, so that the breaking torque is maintained constant, and the reliability and durability of the device can be improved.

Since the surface layer 22 is formed on the engagement surface 15 and the surface layer 23 is formed on the engagement surface 21, the engagement surface 15 and the engagement surface 21 are welded to each other. And wear can be more effectively prevented, and rust can be prevented from being generated on both engaging surfaces. Therefore, the pressure contact force of the leaf spring 12 to the curved recess can be further stabilized, and the reliability and durability of the device can be further improved.

[0022]

As described above, according to the power transmission mechanism of the present invention, the engaging surface of the leaf spring mounting portion on the mounting portion side and the leaf spring side engaging surface of the end portion of the leaf spring are both. Since it is formed of a substantially cylindrical surface, the slipperiness of the engaging surfaces is improved, and welding and wear of the engaging surfaces can be effectively prevented.
Therefore, the pressure contact force of the leaf spring with respect to the curved concave portion can be stabilized, so that the power transmission mechanism having excellent reliability and durability can be realized.

[Brief description of drawings]

FIG. 1 is a front view of a power transmission mechanism according to an embodiment of the present invention in a power transmission state.

FIG. 2 is a cross-sectional view taken along the line II-II of the power transmission mechanism in the state of FIG.

FIG. 3 is a front view of the power transmission mechanism according to the embodiment of the present invention in a power cut-off state.

FIG. 4 is a sectional view taken along the line IV-IV of the power transmission mechanism in the state of FIG.

5 is an enlarged view of part A in FIG. 1. FIG.

FIG. 6 is a front view of the power transmission mechanism according to the applicant's previous proposal.

[Explanation of symbols]

1 Power transmission mechanism 2 housing 3 ball bearings 4 pulley 5 hubs 6 Central part of hub 7 Compressor shaft 8 Small diameter part of shaft 9 thread groove 10 nuts 11 rims 12 leaf spring 12a side 13 End of leaf spring 14 Leaf spring mounting part 15 Leaf spring mounting side engagement surface 16 rims 17 curved recess 17a side 18 walls 19 Elastic member 20 Cylindrical part 21 leaf spring side engaging surface 22, 23 Surface layer

Claims (9)

[Claims] 1. A pair of plates having a pulley, a shaft arranged concentrically with the pulley, and a hub fixed to the shaft, the pair of plates engaging an end portion of a leaf spring on an inner peripheral surface of the pulley. Power is transmitted from the pulley to the hub by providing a spring mounting portion and a curved concave portion on the outer peripheral surface of the hub with which the leaf spring is in pressure contact, and by bending the central portion of the leaf spring into pressure contact with the curved concave portion of the hub. In the power transmission mechanism, the mounting portion side engaging surface with which the leaf spring of the leaf spring mounting portion is engaged and the leaf spring side engaging surface of the leaf spring end portion engaged with the engaging surface are substantially formed. A power transmission mechanism characterized by being formed on a cylindrical surface. 2. The power transmission mechanism according to claim 1, wherein a cylindrical portion is provided at an end portion of the leaf spring, and an outer peripheral surface of the cylindrical portion forms the leaf spring side engagement surface. 3. The power transmission mechanism according to claim 2, wherein the cylindrical portion is provided integrally with the leaf spring. 4. The power transmission mechanism according to claim 1, wherein a different surface layer is interposed between the leaf spring side engagement surface and / or the mounting portion side engagement surface. 5. The surface layer is formed on a leaf spring side engagement surface and / or a mounting portion side engagement surface.
Power transmission mechanism. 6. The surface layer comprises a resin layer.
Or a power transmission mechanism of 5. 7. The power transmission mechanism according to claim 6, wherein the resin layer is made of a fluororesin. 8. The power transmission mechanism according to claim 4, wherein the surface layer is a nitriding layer. 9. The power transmission mechanism according to claim 1, wherein the power transmission mechanism is a compressor power transmission mechanism.