JPH08121336A - Power transmission structure of clutcheless compressor - Google Patents

Abstract

PURPOSE: To provide a power transmission structure which transmits a load torque to a vehicle engine after relieving a variation of the load torque on a clutchless compressor side, and also shuts off the transmission of overload. CONSTITUTION: A rotation of a vehicle engine is transmitted to a pulley 6 through a belt 7, and the rotation of the pulley 6 is transmitted to a rotating shaft 4 through a buffering rubber 10, a driving force transmission body 8, and a coiled fastening spring 12. Also the coiled fastening spring 12 is wound and fixed to the projected end part 4-1 of the rotating shaft 4. The extended end part 12-1 of the coiled fastening spring 12 is engaged with the hook recessed part 8-1 of the driving force transmission body 8. Then the buffering rubber 10 transmits a load torque to the pulley 6 after relieving the load toque on the compressor side. When an overload is generated, the coiled fastening spring 12 is rotated relative to the rotating shaft 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission structure in a clutchless compressor for transmitting a driving force of an external drive source to a rotary shaft via a pulley.

[0002]

2. Description of the Related Art In a clutchless compressor that does not use an electromagnetic clutch for connecting and disconnecting power transmission between an external drive source and a rotary shaft of the compressor, an on-off shock is experienced especially when mounted on a vehicle. The drawback of bad feeling can be eliminated. Further, it is possible to reduce the weight and cost of the entire compressor. However, in such a clutchless compressor, the fluctuation of the load torque on the compressor side is not alleviated and spreads to the vehicle engine, so that the rotational speed of the vehicle engine fluctuates.

In the clutchless compressor disclosed in Japanese Utility Model Laid-Open No. 63-142460, an engaging recess is provided on an annular projecting wall formed on the pulley, and an engaging recess is provided on the peripheral surface of the hub. Is provided. One end of the drive lever is inserted into the engagement recess on the protruding wall side, and the other end of the drive lever is inserted into the engagement recess on the hub side via an annular leaf spring. The rotation of the pulley is transmitted to the rotating shaft via the drive lever and the leaf spring. The fluctuation of the load torque on the compressor side is alleviated by the swing of the drive lever and the elastic deformation of the leaf spring, and the fluctuation of the rotation speed of the vehicle engine due to the fluctuation of the load torque is suppressed. When the load torque on the compressor side becomes excessive, the other end of the drive lever comes off the recess of the leaf spring, and the transmission of the overload to the pulley side is cut off.

[0004]

However, the structure in which a plurality of drive levers are swingably supported and the swing displacement of the drive levers is received by a leaf spring is complicated. With such a complicated structure, the number of parts and the number of assembly steps increase,
The cost of the clutchless compressor increases. Further, when an overload occurs, the drive lever is continuously disengaged from the recess of the leaf spring, and the compressor cannot be operated.

The present invention provides a power transmission structure for a clutchless compressor which can suppress the influence of load torque fluctuations on the compressor side in spite of a simple structure and can operate the compressor even after an overload occurs. The purpose is to

[0006]

To this end, according to the first aspect of the invention, a self-returning torque limiter is interposed between the projecting end portion of the rotary shaft projecting from the housing and the driving force transmitting body to transmit the driving force. A cushioning rubber is interposed between the body and the pulley,
The transmission of the pulley is transmitted to the driving force transmission body via the cushioning rubber.

According to the second aspect of the invention, the tightening spring is wound around the protruding end of the rotary shaft, and one end of the tightening spring is engaged with the driving force transmitting body to form the torque limiter. In the invention of claim 3, a tightening spring is wound around the projecting end of the rotary shaft projecting from the housing to form a torque limiter, and the extended end of the one end of the tightening spring is extended to the pulley side. The rotation of the pulley is transmitted to the rotation shaft via the extending end portion so as to be elastically displaceable in the circumferential direction.

According to the invention of claim 4, the swash plate is tiltably supported by the rotary support fixed to the rotary shaft, and the swash plate is responsive to the difference between the pressure in the crank chamber and the suction pressure via the single-headed piston. The target is a variable displacement compressor that controls the inclination angle of the crankshaft to supply the pressure in the discharge pressure region to the crank chamber and releases the pressure in the crank chamber to the suction pressure region to regulate the pressure in the crank chamber. The extension end, which is an extension of one end of the winding spring, is hung on the pulley side so as to urge it in a direction projecting from the housing.

[0009]

The fluctuation of the load torque on the compressor side is alleviated by the elastic deformation of the buffer rubber and transmitted to the pulley side. When the load torque on the compressor side becomes excessive, torque transmission in the torque limiter is cut off. When the overload is eliminated, the torque limiter returns to the torque transferable state.

According to the second aspect of the present invention, the fluctuation of the load torque on the compressor side is transmitted to the pulley side via the winding tightening spring wound around the protruding end of the rotating shaft, the driving force transmitting body and the buffer rubber. . When the load torque on the compressor side becomes excessive, the tightening spring wound around the protruding end of the rotary shaft rotates relative to the rotary shaft, and the torque transmission in the torque limiter is cut off.

According to the third aspect of the present invention, the fluctuation of the load torque on the compressor side is alleviated by the elastic deformation action at the extension end of the winding spring and is transmitted to the pulley side. When the load torque on the compressor side becomes excessive, torque transmission in the torque limiter is cut off. This winding tightening spring also has a cushioning function.

According to the fourth aspect of the invention, the elastic deformation action of the extending end portion of the winding tightening spring applies a preload in the thrust direction to the rotating shaft. This winding tightening spring also has a preloading function.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment embodying the present invention will now be described with reference to FIG.
~ It demonstrates based on FIG. As shown in FIG. 1, a front housing 2 is joined to the front end of the cylinder block 1, and a rear housing 3 is joined to the rear end of the cylinder block 1. A rotary shaft 4 is rotatably supported between a front housing 2 forming a crank chamber 2-1 and a cylinder block 1. The front end of the rotary shaft 4 projects from the crank chamber 2-1 to the outside.

A support cylinder 2-2 is integrally formed with the front housing 2, and an angular bearing 5 is supported by the support cylinder 2-2 so as to be slidable in the axial direction of the rotary shaft 4. A pulley 6 is fixed to the outer ring of the angular bearing 5. The pulley 6 is composed of a connecting board 6-1 fixed to the outer ring of the angular bearing 5 and a pulley body 6-2 fixed to the connecting board 6-1. The pulley body 6-2 is connected via a belt 7 to a vehicle engine (not shown) that is an external drive source.

The angular bearing 5 receives both the thrust load and the radial load. A disc spring type preloading spring 11 is interposed between the inner ring of the angular bearing 5 and the front housing 2. The preload applying spring 11 biases the angular bearing 5 in a direction in which the rotary shaft 4 projects from the front housing 2.

As shown in FIGS. 1 and 2, an annular cushion rubber 10 is bonded to the inner peripheral surface of the connecting substrate 6-1 with an adhesive material. An annular driving force transmission body 8 is bonded to the inner peripheral surface of the cushioning rubber 10 with an adhesive material. The protruding end portion 4-1 of the rotary shaft 4 protruding from the crank chamber 2-1 to the outside has an annular driving force transmission body 8.
Is inserted through the center hole of the. A nut 9 is screwed onto the tip of the protruding end 4-1. The spring force of the preloading spring 11 is the angular bearing 5, the pulley 6, the cushion rubber 1
0, the driving force transmitting body 8 and the nut 9 are transmitted to the rotating shaft 4.

As shown in FIGS. 2 and 3, a coiled winding spring 12 is attached to the protruding end 4-1 of the rotary shaft 4. The tightening spring 12 is tightly connected to the projecting end 4-1 by its spring force. One end of the winding tightening spring 12 extends in the tangential direction of the projecting end 4-1 and this extending end 12-1 is hooked in the hook recess 8-1 of the driving force transmission body 8. . The rotation of the pulley 6 is made by the cushioning rubber 1
0, the driving force transmitting body 8 and the winding tightening spring 12 are transmitted to the rotating shaft 4. The winding tightening spring 12 is a right-handed spring and coincides with the rotation direction of the rotary shaft 4.

A rotary support 14 is fixed to the rotary shaft 4. A swash plate 15 is supported on the rotary shaft 4 so as to be slidable and tiltable in the axial direction of the rotary shaft 4. As shown in FIG. 4, the swash plate 15 is a support arm 14-1 on the rotary support 14.
And the pair of guide pins 16 and 17 are linked to each other, the rotating shaft 4
Can be tilted in the axial direction and can rotate integrally with the rotary shaft 4. The tilting of the swash plate 15 is guided by the slide guide relationship between the support arm 14-1 and the guide pins 16 and 17, and the slide support action of the rotary shaft 4.

The rear end of the rotary shaft 4 has a deep groove ball bearing member 18
And, it is supported by the inner peripheral surface of the accommodation hole 20 in the cylinder block 1 via the blocking body 19. An intake passage 21 is formed in the center of the rear housing 3. The suction passage 21 communicates with the accommodation hole 20, and the suction passage 21 on the accommodation hole 20 side.
A positioning surface 22 is formed around the opening. The tip of the blocking body 19 can contact the positioning surface 22. When the tip of the blocking body 19 abuts the positioning surface 22, the blocking body 19 is restricted from moving in the direction away from the swash plate 15, and the communication between the suction passage 21 and the accommodation hole 20 is blocked.

Due to the decrease of the swash plate inclination angle, the swash plate 15 becomes the blocking member 1.
As it moves to the 9 side, the swash plate 15 comes into contact with the transmission cylinder 23 and pushes the transmission cylinder 23 and the deep groove ball bearing member 18 toward the positioning surface 22 side. The deep groove ball bearing member 18 receives a load not only in the radial direction of the rotating shaft 4 but also in the thrust direction.
Therefore, the blocking body 19 is biased toward the positioning surface 22 side against the spring force of the suction passage opening spring 24, and the tip of the blocking body 19 contacts the positioning surface 22.

The minimum inclination angle of the swash plate 15 is slightly larger than 0 °. This minimum tilt angle state is brought about when the blocking body 19 is arranged in the closed position that blocks the communication between the suction passage 21 and the accommodation hole 20. The maximum inclination of the swash plate 15 is the rotation support 14
It is regulated by the contact between the inclination regulating protrusion 14-2 and the swash plate 15.

The rotational movement of the swash plate 15 is converted into a forward / backward reciprocating movement of the single-headed piston 26 in the cylinder bore 1-1 via the shoe 25. As shown in FIGS. 1 and 5, the rear housing 3 has a suction chamber 3-1 and a discharge chamber 3-2 defined therein. The refrigerant gas in the suction chamber 3-1 pushes the suction valve 29 away from the suction port 28 by the returning movement of the single-headed piston 26 and flows into the cylinder bore 1-1. The refrigerant gas flowing into the cylinder bore 1-1 pushes the discharge valve 31 out of the discharge port 30 by the forward movement of the single-headed piston 26, and the discharge chamber 3
It is discharged to -2.

A thrust bearing 27 is interposed between the rotary support 14 and the front housing 2. The compression reaction force from the cylinder bore 1-1 is generated by the single-headed piston 26,
It is received by the front housing 2 via the shoe 25, the swash plate 15, the guide pins 16 and 17, the rotary support 14 and the thrust bearing 27.

The suction chamber 3-1 is provided with a receiving hole 20 through a through hole 32.
Is in communication with. When the blocking body 19 is arranged in the closed position, the passage 32 is blocked from the suction passage 21. Rotating shaft 4
A passage 33 is formed inside. The passage 33 communicates the crank chamber 2-1 with the inside of the cylinder of the blocking body 19. Blocker 1
At the tip of 9, a pressure release port 19-1 is formed. The pressure release port 19-1 communicates the accommodation hole 20 with the inside of the cylinder of the blocking body 19.

The crank chamber 2-1 and the discharge chamber 3-2 are connected by a pressure supply passage 34. An electromagnetic opening / closing valve 35 is interposed on the pressure supply passage 34. The valve body 35-2 closes the valve hole 35-3 by exciting the solenoid 35-1 of the electromagnetic opening / closing valve 35. When the solenoid 35-1 is demagnetized, the valve body 35-2 opens the valve hole 35-3.

A suction passage 21 for introducing the refrigerant gas into the suction chamber 3-1 and a discharge port 1-2 for discharging the refrigerant gas from the discharge chamber 3-2.
And are connected by an external refrigerant circuit 36. A condenser 37, an expansion valve 38 and an evaporator 39 are provided on the external refrigerant circuit 36. The expansion valve 38 controls the refrigerant flow rate according to the fluctuation of the gas pressure on the outlet side of the evaporator 39. A temperature sensor 40 is installed near the evaporator 39. The control computer C controls the demagnetization of the solenoid 35-1 based on the detected temperature information obtained from the temperature sensor 40. The control computer C commands the demagnetization of the solenoid 35-1 when the detected temperature becomes equal to or lower than the set temperature under the ON state of the air conditioner operation switch 41. The temperature below this set temperature is the evaporator 39
Reflects the situation in which frost is likely to occur. or,
The control computer C turns on the air conditioner operation switch 41.
Under the state, the solenoid 35-1 is demagnetized by the specific rotation speed fluctuation detection information from the rotation speed detector 42 of the vehicle engine. Further, the control computer C demagnetizes the solenoid 35-1 by turning off the air conditioner operation switch 41. When the solenoid 35-1 is demagnetized, the pressure supply passage 34
Opens, and the discharge chamber 3-2 and the crank chamber 2-1 communicate with each other. Therefore, the refrigerant gas in the discharge chamber 3-2 flows into the crank chamber 2-1, and the pressure in the crank chamber 2-1 increases. Crank chamber 2
Due to the pressure increase in -1, the inclination of the swash plate 15 shifts to the minimum inclination side. When the tip of the blocking body 19 comes into contact with the positioning surface 22, the swash plate inclination angle becomes minimum, and the refrigerant gas from the external refrigerant circuit 36 to the suction chamber 3-1 is blocked.

Since the minimum inclination of the swash plate is not 0 °, the discharge from the cylinder bore 1-1 to the discharge chamber 3-2 is performed even when the inclination of the swash plate is minimum. The refrigerant gas in the suction chamber 3-1 is sucked into the cylinder bore 1-1 and discharged into the discharge chamber 3-2. That is, when the swash plate tilt angle is at a minimum, the discharge chamber 3-2, the pressure supply passage 34, the crank chamber 2-1, the passage 33, the pressure release port 19-1, the suction chamber 3-2, and the cylinder bore 1-1 are passed. There is a circulation passage inside the compressor. The lubricating oil flowing with the refrigerant gas lubricates the inside of the compressor via the circulation passage.
There is a pressure difference between the discharge chamber 3-2, the crank chamber 2-1, and the suction chamber 3-1. The pressure difference and the passage cross-sectional area at the pressure release passage 19-1 stably hold the swash plate 15 at the minimum inclination angle.

When the solenoid 35-1 is excited, the pressure supply passage 34 is closed. Since there is a pressure difference between the inside of the crank chamber 2-1 and the inside of the suction chamber 3-1, the pressure in the crank chamber 2-1 is reduced based on the pressure released through the passage 33 and the pressure release port 19-1. Do it. Due to this pressure reduction, the tilt angle of the swash plate 15 shifts from the minimum tilt angle to the maximum tilt angle.

In the clutchless compressor which performs such an operation, the fluctuation of the load torque on the compressor side is transmitted from the rotary shaft 4 to the pulley 6 via the winding tightening spring 12, the driving force transmitting body 8 and the buffer rubber 10. It The buffer rubber 10 is elastically deformed in the circumferential direction, and the fluctuation of the load torque on the compressor side causes
Is relieved by the elastic deformation action of and is transmitted to the pulley 6 side.

When the load torque on the compressor side becomes excessive, if the excessive load torque spreads to the vehicle engine side, the vehicle engine stalls. In this embodiment, when an excessive load torque is generated, the winding tightening spring 12 expands in diameter, and relative rotation occurs between the winding tightening spring 12 and the rotary shaft 4. Therefore, the excessive load torque does not spread to the vehicle engine side, and the engine stall does not occur. When the overload is removed, the winding tightening spring 12 and the rotary shaft 4 rotate integrally. That is, the winding tightening spring 12 is a self-returning torque limiter that cuts off torque transmission against overload and returns to the state of transmitting torque after overload is removed. Therefore, the compressor can be operated after the overload is removed.

Since the rotating shaft 4 may be displaced in the thrust direction and rattling, it is necessary to prevent the rattling by applying a preload to the rotating shaft 4 in the thrust direction. In the compressor of this embodiment, if a preload is applied in the direction in which the rotary shaft 4 is projected from the front housing 2, this preload is applied to the front housing 2 via the thrust bearing 27.
Accepted by. The preload applying spring 11 applies a preload to the rotating shaft 4 via the angular bearing 5, the pulley 6, the buffer rubber 10, the driving force transmitting body 8 and the nut 9. The magnitude of the preload of the preload applying spring 11 is adjusted by the screwing position of the nut 9. The preload increases as the nut 9 approaches the front housing 2 side. That is, it is easy to adjust the preload.

Next, the embodiment shown in FIG. 6 will be described. In this embodiment, a hooking recess 6-3 is formed in the connecting substrate 6-1 of the pulley 6. One end of the tightening spring 12 wound around the protruding end 4-1 of the rotary shaft 4 extends in the tangential direction of the rotary shaft 4, and the extending end 12-2 is the hooking recess 6-3. Have been hung on. An annular preload transmission plate 13 is interposed between the nut 9 and the extending end portion 12-2. The other structure is the same as that of the first embodiment.

The fluctuation of the load torque on the compressor side is transmitted to the pulley 6 through the engagement between the extended end 12-2 of the winding spring 12 and the latch recess 6-3. The extended end portion 12-2 is elastically displaced in the circumferential direction of the pulley 6, and this elastic displacement action alleviates the fluctuation of the load torque and transmits it to the pulley. The spring force of the preload applying spring 11 is the angular bearing 5, the pulley 6,
It is transmitted to the rotary shaft 4 via the extended end portion 12-2, the preload transmission plate 13 and the nut 9. That is, the winding tightening spring 12 has not only a torque limiter function but also a load torque fluctuation relaxing function and a preload transmission function.

Next, the embodiment shown in FIG. 7 will be described. The extended end portion 12-3 of the winding spring 12 is engaged with the end surface of the annular driving force transmission body 43 fixed to the inner peripheral surface of the buffer spring 10, and the preloading spring of each of the above-described embodiments is engaged. Is omitted.
The angular bearing 5 is fixed to the support cylinder 2-2. The spring force at the extending end 12-3 urges the rotating shaft 4 in a direction projecting from the front housing 2. That is, the extending end portion 12-3 of the winding tightening spring 12 applies a preload to the rotating shaft 4, and the winding tightening spring 12 has not only a torque limiter function but also a preload applying function.

Next, the embodiment shown in FIG. 8 will be described. In this embodiment, the preload transmission flange 6-4 is formed on the inner peripheral surface of the connection board 6-1.
Are formed. Position restriction ring 4 on protruding end 4-1
A thrust bearing 45 is interposed between the No. 4 and the preload transmission flange 6-4. An annular cushion rubber 10 is fixed to the preload transmission flange 6-4.
A clutch plate 46 is fastened to this. A clutch plate 47 is supported on the projecting end 4-1 so as not to be relatively rotatable and slidable. A clutch plate 47 is pressed against the clutch plate 46 by the spring force of a compression spring 48. Nut 9
Serves as a spring bearing for the compression spring 48. Clutch plates 46, 4
7 and the compression spring 48 constitute a self-returning type torque limiter.

The fluctuation of the load torque on the compressor side is transmitted to the pulley 6 via the clutch plate 47, the clutch plate 46 and the buffer rubber 10. The preload of the preload applying spring 11 is transmitted to the rotary shaft 4 via the angular bearing 5, the connecting substrate 6-1, the preload transmission flange 6-4, the thrust bearing 45 and the position regulating ring 44. The cushioning rubber 10 reduces the fluctuation of the load torque on the compressor side and transmits it to the pulley 6 side, and the self-returning torque limiter composed of the clutch plates 46, 47 and the compression spring 48 blocks overload transmission. Although the spring action direction of the compression spring 48 is the same as the spring action direction of the preload applying spring 11, the presence of the preload transmission flange 6-4 and the thrust bearing 45 causes the spring action of the both springs 48, 11 to the rotating shaft 4. Be independent. That is, the pressure contact force between the clutch plates 46 and 47 and the preload can be optimally set independently of each other.

[0037]

As described above in detail, in the invention of claim 1, a self-returning torque limiter is interposed between the projecting end of the rotary shaft projecting from the housing and the driving force transmitting body.
A cushioning rubber is interposed between the driving force transmitting body and the pulley, and the transmission of the pulley is transmitted to the driving force transmitting body via the cushioning rubber, so that fluctuations in the load torque on the compressor side are alleviated. Can be transmitted to the side, and the compressor can be operated after the overload is removed.

According to the second aspect of the present invention, since the tightening spring is wound around the protruding end of the rotary shaft and one end of the spring is engaged with the driving force transmitting body to form the torque limiter, the load on the compressor side is reduced. It is possible to reduce the torque fluctuation and transmit it to the pulley side, and the compressor can be operated after the overload is eliminated.

According to the third aspect of the invention, a torque limiter is constructed by winding a tightening spring around the projecting end of the rotary shaft projecting from the housing, and one end of the tightening spring is extended to extend the end. Is attached to the pulley side so that it can be elastically displaced in the circumferential direction, and the rotation of the pulley is transmitted to the rotating shaft through the extended end portion. Can be transmitted to.

In the fourth aspect of the present invention, since the extended end of the winding spring, which extends from one end of the spring, is hooked on the pulley so as to urge the rotary shaft in the direction of protruding from the housing, the torque limiter is used. A preload may be applied to the rotating shaft.

[Brief description of drawings]

FIG. 1 is a side sectional view of an entire compressor according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an enlarged side sectional view of an essential part.

FIG. 4 is a sectional view taken along line BB of FIG.

5 is a cross-sectional view taken along the line CC of FIG.

FIG. 6 is an enlarged side sectional view of an essential part showing another example.

FIG. 7 is an enlarged side sectional view of an essential part showing another example.

FIG. 8 is an enlarged side sectional view of an essential part showing another example.

[Explanation of symbols]

2 ... Front housing, 2-2 ... Support cylinder which is a part of housing, 4 ... Rotating shaft, 4-1 ... Projection end part, 5 ... Angular bearing which is a bearing member, 6 ... Pulley, 8, 43
... driving force transmitting body, 10 ... cushioning rubber, 11 ... preload applying spring, 12 ... winding tightening spring constituting a torque limiter, 1
2-1, 12-2, 12-3 ... Extending end portions, 46, 47 ... Clutch plates forming a torque limiter, 48 ... Compression springs forming a torque limiter.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Kawamura 2-chome, Toyota-cho, Kariya city, Aichi stock company Toyota Industries Corp.

Claims (4)

[Claims] 1. A clutchless compressor for transmitting a driving force of an external drive source to a rotating shaft via a pulley, wherein a self-reset type is provided between a protruding end of the rotating shaft protruding from a housing and a driving force transmitting body. A power transmission structure in a clutchless compressor in which a torque limiter is interposed, a cushioning rubber is interposed between a driving force transmission body and a pulley, and transmission of the pulley is transmitted to the driving force transmission body via the cushioning rubber. 2. The power transmission in the clutchless compressor according to claim 1, wherein the torque limiter is a winding spring which is wound around a protruding end of a rotary shaft and whose one end is engaged with a driving force transmitting body. Construction. 3. In a clutchless compressor for transmitting the driving force of an external drive source to a rotary shaft via a pulley, a torque limiter is constructed by winding a tightening spring around the protruding end of the rotary shaft protruding from the housing. The extension end of the winding tightening spring, which extends from one end, is hooked on the pulley so as to be elastically displaceable in the circumferential direction, and the rotation of the pulley is transmitted to the rotary shaft via the extension end. Power transmission structure for the clutchless compressor. 4. A compressor supports a swash plate tiltably on a rotary support fixed to a rotary shaft, and adjusts the swash plate according to the difference between the pressure in the crank chamber and the suction pressure via a single-headed piston. It is a variable displacement compressor that controls the tilt angle and supplies the pressure in the discharge pressure region to the crank chamber and releases the pressure in the crank chamber to the suction pressure region to regulate the pressure in the crank chamber. The clutchless compressor according to any one of claims 2 and 3, wherein one end of the winding tightening spring is extended so as to be biased in a projecting direction, and the extended end is hooked on the pulley side. Power transmission structure in.