JP2000356253A - Power transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power transmission prevented from the breaking of a belt caused by a slip of the belt. SOLUTION: A pulley 3 is separated into a pulley body 3A and a pulley outer diameter part 3B forming a surface part over which a belt is laid, and both of them are jointed by an adhesive layer 7. When a compressor is locked, for instance, to increase load torque of the shaft 2 side and the belt starts slipping on the pulley outer diameter part 3B, frictional heat is generated between the belt and the pulley outer diameter part 3B in association with the slip of the belt, and the frictional heat is conducted to the adhesive layer 7 through the pulley outer diameter part 3B high in heat conductivity. At this time, if a thermoplastic resin is used as the adhesive layer 7, the thermoplastic resin is fused receiving the frictional heat, so that adhesive strength of the pulley body 3A and pulley outer diameter part 3B is lowered to put the pulley body 3A and pulley outer diameter part 3B in a relatively rotatable state, and the pulley outer diameter part 3B can be rotated receiving rotational power transmitted through the belt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission device for transmitting rotational power, and more particularly to an overload torque cutoff mechanism for cutting off transmission of overload torque.

[0002]

2. Description of the Related Art As a prior art, for example, Japanese Patent Application Laid-Open No. H10-4
A power transmission mechanism disclosed in Japanese Patent No. 7244 is known. This power transmission mechanism transmits the rotational force transmitted to the pulley to the shaft of the compressor, and an interposition member having an elastic deformation portion made of a thermoplastic resin is disposed between the pulley and the shaft. Have been. The interposition member is connected to one of the pulley and the shaft, and is always pressed against the other so as to be integrally rotatable. With this configuration, when the load torque on the shaft side fluctuates, the elastic deformation portion elastically deforms to absorb the torque fluctuation, and when the load torque becomes excessive, the elastic deformation is caused by the frictional heat caused by the relative sliding of the press contact portion. The melting of the deformed portion interrupts the transmission of the overload torque from the shaft to the pulley.

[0003]

However, in the above configuration, the set value at which the press-contact portion starts to slide relative to the load torque on the shaft side is set sufficiently high in order to avoid malfunction during normal operation. There is a need. For this reason, for example, in a vehicle layout in which the belt winding angle of the pulley is small, or in a vehicle in which the belt tension is set low, it is difficult to completely prevent the occurrence of belt slippage, and there is a possibility that the belt may be worn out due to belt wear. Was. The present invention has been made based on the above circumstances, and an object of the present invention is to provide a power transmission device that can prevent a belt from being broken due to a belt slip.

[0004]

The pulley has a pulley body rotatably supported and a surface portion on which the belt is looped and provided separately from the pulley body. A pulley outer diameter portion rotatably assembled to the pulley body and joined to the pulley body via a joining material, wherein the joining material has friction generated when relative sliding between the pulley and the belt occurs. It is characterized in that the bonding strength is reduced by receiving heat. According to this configuration, when the joining force of the joining material is reduced and the joining state between the pulley body and the outer diameter portion of the pulley is released, the pulley body and the outer diameter portion of the pulley can be relatively rotated. This allows the outer diameter portion of the pulley to rotate by receiving the rotational power transmitted via the belt, so that belt slippage with respect to the outer diameter portion of the pulley is eliminated and belt breakage can be prevented.

The pulley body has a flat bearing on an outer diameter surface, and an outer diameter portion of the pulley is fitted on an outer peripheral surface of the flat bearing, and the outer diameter portion of the pulley is flat by a joining material. It is joined to the bearing. In this case, when the joining force of the joining material is reduced and the joining state between the flat bearing and the outer diameter portion of the pulley is released, the outer diameter portion of the pulley can idle with respect to the flat bearing. This allows
Belt slippage with respect to the pulley outer diameter portion is eliminated, and belt breakage can be prevented.

(Means of Claim 3) The outer diameter portion of the pulley can be made of a steel plate or an aluminum alloy in order to enhance thermal conductivity. Thus, even when the belt winding angle is small, the frictional heat generated by the belt slip can be transmitted to the entire circumference of the pulley in a short time, and the belt slip can be eliminated in a short time.

(Means of Claim 4) As the joining material, for example, a thermoplastic resin or a resin-based adhesive can be used. Here, in the case of a thermoplastic resin, by receiving and melting the frictional heat generated by the belt slip, the joining force is reduced and the joining state between the pulley main body and the outer diameter portion of the pulley is released. In the case of a resin-based adhesive, the adhesive force is reduced due to frictional heat generated by belt slippage, and the bonded portion is released by receiving shearing stress in the rotating direction. As a result, the joining force disappears and the joining state between the pulley body and the outer diameter portion of the pulley is released.

(Means of Claim 5) As the joining material, for example, a low melting point metal such as solder can be used. The low-melting-point metal such as solder melts by receiving the frictional heat generated by the slip of the belt, so that the joining force is reduced and the joining state between the pulley body and the outer diameter portion of the pulley can be released.

(Means of Claim 6) The power transmission device according to claims 1 to 5 is provided in a compressor of a refrigeration cycle,
The rotary power transmitted to the pulley is constantly transmitted to the shaft of the compressor. In this case, even if the load torque on the shaft side suddenly increases due to the lock of the compressor or the like, since the outer diameter portion of the pulley can rotate with respect to the pulley body,
The overload torque on the shaft side is not transmitted to the outer diameter portion of the pulley, and does not affect the operation state (engine speed) of the vehicle engine via the belt.

[0010]

Next, an embodiment of the present invention will be described with reference to the drawings. (First Embodiment) FIG. 1 is a half sectional view of a power transmission device 1. The power transmission device 1 transmits rotational power of a vehicle engine to a shaft 2 of a compressor, and as shown in FIG.
A pulley 3 that rotates by transmitting the rotational power of the engine, a connecting member 5 connected to the pulley 3 via a rubber body 4,
It comprises a hub 6 fixed to the shaft 2 of the compressor.

The pulley 3 is separated into a pulley body 3A and a pulley outer diameter portion 3B, and both are joined by an adhesive layer 7 (joining material of the present invention). The pulley body 3A is made of, for example, resin and constitutes most of the entire pulley, and is rotatably supported by a housing 9 of the compressor via a bearing 8. The pulley outer diameter portion 3B forms a surface portion around which the belt is wound, and is made of a metal plate having a high thermal conductivity (for example, aluminum), and corresponds to the contact surface shape of the belt as shown in FIG. The cross section is processed into an uneven shape.
The pulley body 3A that supports the pulley outer diameter portion 3B
Of the pulley outer diameter portion 3B is also processed into a concave-convex section. As the adhesive layer 7, for example, a thermoplastic resin or a resin-based adhesive can be used. As shown in FIG. 1, the adhesive layer 7 is interposed in a layered manner over the entire surface of the pulley main body 3A and the outer surface of the pulley.

The rubber member 4 interposed between the pulley 3 and the connecting member 5 absorbs torque fluctuations on the shaft 2 side, and is provided at a plurality of positions, for example, in the circumferential direction. The connecting member 5 has one end joined to the rubber body 4 and the other end joined to the hub 6, and transmits the rotation of the pulley 3 to the hub 6. Hub 6
Is fixed to an end of the shaft 2 with a bolt 10 and rotates integrally with the shaft 2.

Next, the operation of this embodiment will be described. The rotational power transmitted from the vehicle engine to the pulley 3 via the belt is transmitted to the connecting member 5 via the rubber member 4, and further transmitted to the compressor shaft 2 via the hub 6 which rotates integrally with the connecting member 5. The shaft 2 is rotated by the transmission. Here, for example, when the compressor locks and the load torque on the shaft 2 increases, and the load torque becomes larger than the rotation torque transmitted to the pulley 3 via the belt, the pulley outer diameter portion 3B
The belt starts to slip.

When frictional heat is generated between the belt and the outer diameter portion 3B of the pulley due to the slippage of the belt, the frictional heat is transmitted to the adhesive layer 7 via the outer diameter portion 3B having a high thermal conductivity. At this time, if, for example, a thermoplastic resin is used as the adhesive layer 7, the thermoplastic resin is melted by receiving frictional heat, so that the adhesive force between the pulley body 3A and the outer diameter portion 3B of the pulley decreases. Then, the joined state between the pulley body 3A and the pulley outer diameter portion 3B is released.

When a resin-based adhesive is used as the adhesive layer 7, since the adhesive force is reduced by receiving frictional heat, the rotational force acting between the pulley body 3A and the pulley outer diameter portion 3B is reduced. Shear forces act on the bonding surface. As a result, when the adhesive surface is released by receiving the shearing force, the joined state between the pulley main body 3A and the pulley outer diameter portion 3B is released. This allows
The pulley body 3A and the outer diameter portion 3B of the pulley can rotate relative to each other, and the outer diameter portion 3B of the pulley can rotate by receiving the rotational power transmitted via the belt.

(Effect of First Embodiment) By the above operation,
Belt slippage with respect to the pulley outer diameter portion 3B is eliminated, and belt breakage can be prevented. As a result, even when the compressor is locked, excessive torque fluctuations on the shaft 2 side are not transmitted to the vehicle engine, and fluctuations in the engine speed due to fluctuations in load torque can be prevented. Further, in the present embodiment, since the pulley outer diameter portion 3B can be relatively rotated with respect to the pulley main body 3A, the pulley main body 3A is made of resin, so that the weight of the entire pulley can be reduced. However, the pulley body 3A does not necessarily need to be made of resin, and may be formed of aluminum, iron, or the like.

(Second Embodiment) FIG. 2 is a half sectional view of the power transmission device 1. As shown in FIG. 2, the power transmission device 1 of the present embodiment includes a metal bearing 11 on an outer diameter surface of a pulley body 3 </ b> A, and a pulley outer diameter portion 3 </ b> B is rotatable on an outer circumference surface of the metal bearing 11. And the pulley outer diameter part 3
B is joined to the metal bearing 11 by the adhesive layer 7. Accordingly, the outer peripheral portion of the pulley outer diameter portion 3 </ b> B is formed as an inner peripheral surface of a cylinder fitted to the metal bearing 11.

The adhesive layer 7 is not necessarily interposed in a layered manner over the entire surface of the metal bearing 11 and the pulley outer diameter portion 3B facing each other. As shown in FIG. It is possible to regulate the relative rotation between the metal bearing 11 and the outer diameter portion 3B of the pulley by being embedded in the concave portions 11a and 3a respectively formed on the facing surfaces of the diameter portion 3B. It is desirable to provide a plurality of (at least one) the rotation restricting portion by the adhesive layer 7 in the circumferential direction of the pulley 3. The metal bearing 11 is made of a material having excellent slidability, such as phosphor bronze, and is fixed to the outer diameter surface of the pulley body 3A by press fitting or bonding.

Next, the operation of this embodiment will be described. As in the first embodiment, the rotational power transmitted from the vehicle engine to the pulley 3 via the belt is transmitted to the shaft 2 of the compressor, and the shaft 2 rotates. Here, for example, when the compressor locks and the load torque on the shaft 2 side increases, and the load torque becomes larger than the rotation torque transmitted to the pulley 3 via the belt, the belt is moved with respect to the pulley outer diameter portion 3B. Begin to slip.

When frictional heat is generated due to the belt slip, the frictional heat is transmitted to the bonding layer 7 through the pulley outer diameter portion 3B having a high thermal conductivity. If so, the thermoplastic resin melts due to frictional heat. Further, when a resin-based adhesive is used, the adhesive force is reduced by frictional heat.
As in the case of the embodiment, a rotational shear force acts on the adhesive surface and the adhesive surface is released. As a result, the joining state between the metal bearing 11 and the pulley outer diameter portion 3B is released, and the metal bearing 11
The outer diameter portion 3B of the pulley is in a state in which the outer diameter portion 3B is able to idle, so that the outer diameter portion 3B of the pulley can rotate by receiving the rotational power transmitted through the belt.

(Effects of the Second Embodiment) In this embodiment, as in the first embodiment, the slippage of the belt with respect to the outer diameter portion 3B of the pulley is eliminated, and the belt can be prevented from being cut. As a result, even when the compressor is locked, excessive torque fluctuations on the shaft 2 side are not transmitted to the vehicle engine, and fluctuations in the engine speed due to fluctuations in load torque can be prevented. In this embodiment, since the metal bearing 11 is provided on the outer diameter surface of the pulley body 3A, the metal bearing 1
When the joining state between the outer diameter portion 1 and the pulley outer diameter portion 3B is released, the pulley outer diameter portion 3B can rotate smoothly with respect to the metal bearing 11. Thereby, the pulley outer diameter portion 3
It is possible to prevent the pulley body 3A from being damaged by the rotation of B.

(Modification) In the above-described embodiment, an example in which a thermoplastic resin or a resin-based adhesive is used as the adhesive layer 7 has been described. Good. For example, a low melting point metal such as solder may be used as the bonding material.

[Brief description of the drawings]

FIG. 1 is a half sectional view of a power transmission device (first embodiment).

FIG. 2 is a half sectional view of a power transmission device (second embodiment).

FIG. 3 is a sectional view of a main part of a pulley (second embodiment).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power transmission device 2 Shaft (rotated body) 3 Pulley 3A Pulley main body 3B Pulley outer diameter part 7 Adhesive layer (joining material) 11 Metal bearing (flat bearing)

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Toshihiro Hayashi 1-1-1, Showa-cho, Kariya-shi, Aichi Pref. F term (for reference) 3J049 AA04 BD07 BF06 BH01 CA03

Claims (6)

[Claims] 1. A power transmission device comprising a pulley to which rotational power is transmitted from the outside via a belt, and constantly transmitting the rotational power transmitted to the pulley to a rotating body, wherein the pulley is rotatable. And a pulley body provided separately from the pulley body to form a surface portion around which the belt is wound, and rotatably assembled to the pulley body, and via a joining material, A pulley outer diameter portion to be joined to the main body, wherein the joining material receives frictional heat generated when the pulley and the belt slide relative to each other, and the joining force is reduced. Transmission device. 2. The pulley body has a flat bearing on an outer diameter surface, and the outer diameter portion of the pulley is fitted on an outer peripheral surface of the flat bearing.
The power transmission device according to claim 1, wherein the outer diameter portion of the pulley is joined to the flat bearing by the joining material. 3. The power transmission device according to claim 1, wherein the outer diameter portion of the pulley is made of a steel plate or an aluminum alloy. 4. The power transmission device according to claim 1, wherein the bonding material is a thermoplastic resin or a resin-based adhesive. 5. The power transmission device according to claim 1, wherein the joining material is a low melting point metal. 6. The power transmission device according to claim 1, wherein
Power provided in a compressor of a refrigeration cycle, wherein rotational power of a vehicle engine is transmitted to the pulley via the belt, and rotational power transmitted to the pulley is constantly transmitted to a shaft of the compressor. Transmission device.