JP5081060B2 - Power transmission device - Google Patents

Description

  The present invention relates to a power transmission device that transmits a rotational force transmitted from a drive source such as an automobile engine to a driven device such as a compressor, and more particularly to an improvement of a power transmission unit to a shaft of the driven device.

  As a power transmission device that transmits a rotational force transmitted from a driving source such as an automobile engine to a driven device such as a compressor, for example, a device described in Patent Document 1 is known. In this power transmission device, as shown in FIG. 5, the rotational force transmitted from a drive source (not shown) such as an automobile engine to the shaft 102 (main shaft) of the driven device 101 (for example, a compressor) It is transmitted via a pulley 103, a torque transmission part 104, and a hub 105. The hub 105 is fixed to the shaft 102 in the rotational direction by a spline or a serration mechanism, and a screw part formed at the end of the shaft 102. It is fixed in the axial direction via a nut 107 screwed to 106 and a washer 108 interposed between the nut 107 and the hub 105. The washer 108 is subjected to a surface hardening treatment, and the washer 108 is press-fitted into the hub 105 or provided with a rotation preventing portion so as to transmit the rotational force between the hub 105 and the washer 108. . Reference numeral 109 in FIG. 5A denotes a pressing member, and the arm portion 112 of the elastic member 111 fixed to the pulley 103 with a bolt 110 is sandwiched between the hub 105 using the elastic spring force of the pressing member 109. Thus, the torque transmission unit 104 is configured between the pulley 103 and the hub 105. The pressing member 109 is fixed to the hub 105 by rivets 113 by caulking.

In such a power transmission device, the hub 105 is not directly fastened to the shaft 102 but is fastened to the shaft 102 by a nut 107 via a washer 108. In general, since settling due to fastening is caused by plastic deformation of a material, it is considered that it occurs roughly when the surface pressure exceeds the elastic region of the material. As for the contact surface pressure, when the fastening axial force is constant, the contact surface pressure is the maximum surface pressure at the minimum portion of the area of the contact portion. Further, it is considered that the elastic limit of the material and the material hardness are in a proportional relationship, and the higher the hardness is, the higher the elastic limit is, and it is difficult for the settling to occur. In the fastening portion as described above, the contact surface includes (1) a step surface at the base of the shaft screw portion 106 (annular step surface 114 with respect to the central screw portion 106) and a member to be fastened (in the case of the above structure, the hub 105). (2) the contact surface between the seat surface of the nut 107 and the washer 108, and the nut contact seat surface of (2) is sufficient compared to the annular step surface 114 of (1). Therefore, countermeasures for part (1) are necessary for sag. Considering further, the annular stepped surface 114 of the shaft 102 has an increased hardness due to the influence of heat treatment due to the subsequent installation portion (working portion) such as spline or serration. Therefore, the hardness of the member that comes into contact with the annular step surface 114 of the shaft 102 is the most important for avoiding settling, and the above-described hardening washer 108 shown in the prior art is required. That is, as compared with the case where the hub 105 is directly fastened to the annular stepped surface 114 of the shaft 102, the fastening at the fastening portion is prevented by fastening the hub 105 via the washer 108 subjected to the curing process. Yes.
JP 2007-107548 A

However, the structure disclosed in Patent Document 1 still has the following problems.
(1) First, the rotational force transmission structure between the washer 108 and the hub 105 is expensive as shown below. When the washer 108 is press-fitted into the hub 105, it is necessary to increase the dimensional accuracy and surface roughness of the outer peripheral surface of the washer serving as the press-fitting surface and the boss portion inner surface of the hub 105, and the press-fitting process, the washer caulking process, etc. The assembly process was also complicated.

(2) Further, in the type in which the washer 108 is fitted into the hub 105, a special washer receiving portion is provided on the hub 105, or a washer periphery stopper is provided on the inner peripheral surface of the washer receiving portion and the outer peripheral surface of the washer 108. There was a need.

  Therefore, the object of the present invention is to pay attention to such problems in the conventional structure, and at the fastening part for fastening the hub to the shaft side, it is possible to reduce component costs and reduce assembly man-hours while realizing prevention of settling. Is to provide a simple power transmission device.

The power transmission device according to the present invention is a power transmission device that transmits a rotational force transmitted from a drive source to a shaft of a driven device via a hub, and the fastening means that connects the hub and the shaft includes a shaft. A nut screwed into a threaded portion formed at an end of the plate, a plate fastened to the shaft by the nut, and an anti-slip washer interposed between the plate and a fastening seating surface of the shaft A coupling means for coupling the plate and the hub, wherein the hardness of the anti-slip washer is higher than the hardness of the plate , and the coupling means includes the hub, the plate, and the drive to the hub. A hub having a rivet that is caulked together with a torque transmitting portion that transmits a rotational force from a power source, and the thickness of the anti-sticking washer is the hub at the portion where the anti-sticking washer is mounted The contact area between the anti-stick washer and the plate is equal to or smaller than the distance between the plates, the contact area between the anti-stick washer and the fastening seat surface of the shaft It is characterized by being larger than .

In such a power transmission device, in order to fasten and fix the hub in the axial direction with respect to the shaft, a plate that is fastened to the shaft side by a nut is provided, and furthermore, a fastening seating surface (that is, a plate and a shaft) An anti-settling washer is interposed between the annular stepped surface of the shaft and the plate and the anti-settling washer are fastened to the shaft by a nut , and the plate and the hub are connected by a coupling means. Also in this, since the plate only needs to be provided on the side surface side of the hub, no significant limitations on the shape and structure, simple and can be configured to a member of inexpensive construction, and coupling of the hub usually also such as rivets Therefore, it is possible to reduce the cost of parts and the number of assembly steps. Moreover, since the anti-settling washer can be formed into a ring-shaped and small-sized small part, it is extremely unlikely to hinder the reduction of parts cost and the number of assembly steps. In the form of Soshiteko the annular shaft being up hardness influenced by the heat treatment for the installation of the most important become a contact portion, a spline or serration or the like for fatigue avoidance in engagement as described above The anti-sticking washer is brought into contact with the stepped surface. By providing the anti-sticking washer with a hardness higher than the hardness of the plate, the anti-sticking is achieved efficiently and reliably. Further , since the hardness of the anti-settling washer that is smaller than that of the plate may be increased, the curing process can be easily performed.

This set-off washer is made harder than the plate by , for example, surface hardening treatment. As the surface hardening treatment, a known method may be adopted as appropriate.

  Moreover, it is preferable that the outer diameter of the anti-sticking washer is larger than the outer diameter of the fastening seat surface of the shaft. As a result, the area of the contact surface between the anti-stick washer and the plate is made sufficiently larger than the area of the contact surface between the anti-stick washer and the fastening seat surface of the shaft, and the contact surface side with the plate is reduced. It is possible to reliably avoid the problem of looseness on this side as surface pressure.

  Further, the anti-sticking washer can adopt a structure provided in a recess formed in the hub. As a result, even if a settling washer is provided, the entire portion can be made compact. In this case, it is preferable that the anti-stick washer is positioned in the radial direction between the outer peripheral portion of the anti-stick washer and the inner peripheral portion of the recess. If comprised in this way, a shaft screw part can be easily inserted now in the anti-sticking washer fixed to the predetermined position with respect to the hub.

Further, the thickness of the anti-sticking washer is equal to or smaller than the distance between the hub and the plate at the portion where the anti-sticking washer is mounted . If comprised in this way, the installation position (assembly position) of a plate does not need to be influenced at all by the presence of an anti-sticking washer, and it becomes possible to reliably prevent the occurrence of play in the connection between the plate and the hub.

In the power transmission device according to the present invention, the above-mentioned coupling means, to use the rivets. Due to the use of rivets, a predetermined connection between the plate and the hub is easily achieved by caulking. Further, in this case, if the rivet adopts a structure in which the hub, the plate, and a torque transmission portion that transmits the rotational force from the drive source to the hub are employed, assembly becomes easier. The number of assembly steps can be further reduced.

  Such a power transmission device according to the present invention can be applied to any power transmission device that transmits a rotational force from a drive source to a shaft of a driven device via a hub, and is used, for example, for a compressor. It is suitable as a power transmission device. Especially, it is suitable as a power transmission device used for a compressor of a vehicle air conditioner, which is mass-produced and has a strong demand for parts cost reduction and assembly man-hours.

  However, the power transmission device according to the present invention is suitable for a fastening structure of a torque transmission unit having a torque limiter function and a shaft of a driven device, but is not suitable for an armature boss and a driven in an electromagnetic clutch which is another power transmission method. The present invention can also be applied to a fastening structure with a device shaft (for example, a compressor shaft), and the same operations and effects as described above can be obtained.

  As described above, according to the power transmission device of the present invention, it is possible to achieve a reduction in component cost by simplifying the production of components, and to improve productivity by simplifying the structure of each component. Further, assembly can be simplified, thereby reducing assembly man-hours and improving productivity.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
< Reference Example 1>
1 to 3 show a power transmission device according to Reference Example 1 of the present invention. FIG. 1A is a longitudinal sectional view, FIG. 1B is a front view of a hub portion, and FIG. Indicates an elastic member used in the torque transmitting portion, and FIG. 3 shows a pressing member. In FIG. 1, reference numeral 1 denotes the entire power transmission device. In this reference example, the driven device is applied as, for example, a power transmission device to a compressor 2 used in a vehicle air conditioner. Rotational force transmitted from a drive source (not shown) such as an automobile engine is transmitted to the shaft 6 (drive shaft) of the compressor 2 as a driven device via the pulley 3, the torque transmission unit 4, and the hub 5. Is done. The hub 5 is fitted to the shaft 6 with a dimensional allowance in the axial direction, and is fixed to the shaft 6 by a spline, a serration, a key / key groove mechanism or the like in the rotational direction. The shaft 6 is rotated integrally with the shaft 6.

  The fastening means for connecting the hub 5 and the shaft 6 and fastening them in the axial direction is a nut 8 screwed into a screw portion 7 formed at the end of the shaft 6, and the shaft 6 by the nut 8, particularly the shaft. A plate-like plate 10 fastened to a fastening seat surface 9 formed as a stepped portion 6, and a rivet 11 as a connecting means for connecting the plate 10 and the hub 5.

  The torque transmission unit 4 includes an elastic member 13 fixed to the pulley 3 with a bolt 12, and a pressing member 14 that sandwiches a distal end portion of an arm portion 13 a of the elastic member 13 between the hub 5 using an elastic spring force. The pressing member 14 is caulked and fixed together with the plate 10 and the hub 5 by a rivet 11. The planar shapes of the elastic member 13 and the pressing member 14 are formed as shown in FIGS. 2 and 3, and the distal end portion of the arm portion 13 a of the elastic member 13 and the distal end portion of the corresponding pressing member 14 are mutually related. Positioning uneven portions 13b and 14b are provided. The rotational force (torque) transmitted from the drive source to the pulley 3 is transmitted from the pulley 3 through the pressing member 14 to the pressing member 14, the hub 5, and the plate 10, but an excessive torque greater than a predetermined torque is transmitted. When trying to do so, the arm portion 13a of the elastic member 13 held between the hub 5 and the pressing member 14 comes off, and the torque transmission is cut off. These mechanisms serve as a so-called torque limiter. It is configured.

  The plate 10 coupled to the hub 5 via the rivet 11 is fastened to the shaft 6 by tightening the nut 8 while being pressed against the fastening seating surface 9 of the shaft 6. At the same time, the axial position with respect to the shaft 6 is fixed. The hardness of the plate 10 is higher than the hardness of the hub 5 by the surface hardening process. As the surface hardening treatment, a known method may be adopted as appropriate.

  In the power transmission device 1 configured as described above, the assembly of the shaft 6 and the torque limiter portion is performed, for example, as follows. The shaft 6 is inserted into the shaft hole of the hub 5, and the fastening seat surface 9, which is the base step surface of the screw portion 7 of the shaft 6 (annular step surface provided with the screw portion 7 at the center), is inserted from the hub 5. The plate 10 having a high hardness is brought into contact, and then fastened with a nut 8 that is screwed into the threaded portion 7 at the tip of the shaft. Torque transmission between the plate 10 and the hub 5 is performed by a rivet 11 with high productivity. Since the hardness of the plate 10 is sufficiently high, sufficient fastening axial force for preventing loosening of the screw of the shaft 6 is ensured. This increase in hardness can be achieved by subjecting the mere disk-shaped plate 10 to a surface hardening treatment, so that the productivity of the plate 10 is not lowered.

As described above, since the settling due to fastening is caused by plastic deformation of the material, it is considered to occur when the surface pressure exceeds the elastic region of the material. Regarding the contact surface pressure, since the fastening axial force is constant, the minimum portion of the area of the contact portion is the maximum surface pressure. In addition, the elastic limit of the material and the material hardness are in a proportional relationship, and the higher the hardness, the higher the elastic limit and the less likely it is to set. In the above-described fastening portion structure, the contact surface includes (1) a ring-shaped fastening seat surface 9 at the base of the screw portion 7 of the shaft 6 and a contact surface of the plate 10 abutted thereon, and (2) a seat surface of the nut 8. Although it is a contact surface with the plate 10, the nut contact seat surface in (2) is sufficiently larger than the seat surface 9 for annular fastening in (1). The contact surface is the rule. The annular fastening seating surface 9 of the shaft 6 has an increased hardness due to the influence of heat treatment due to the subsequent installation of splines, serrations and the like, as described above. Therefore, the hardness of the member that comes into contact with the annular fastening seating surface 9, that is, the hardness of the plate 10 is the most important for avoiding settling in fastening. In this reference example 1, in place of the press-fit washer in the conventional structure shown in FIG. The plate 10 having a hardness higher than 5 was used. Thus, by increasing the hardness of the plate 10, settling due to fastening is appropriately avoided. In addition, by adopting a structure that is fastened via a disk-shaped plate 10 having a very simple shape, a press-fitted portion or the like can be dispensed with, and high accuracy of components is eliminated, reducing component costs and assembling steps. Can be reduced.

FIG. 4 shows a power transmission device 21 according to a second embodiment of the present invention. In FIG. 4, parts having substantially the same structure as the reference example 1 described above are denoted by the same reference numerals as those in FIG. In the second embodiment, an anti-settling washer 24 is interposed between the hub 22 and the plate 23, and the anti-settling washer 24 is provided in a recess 25 formed in the hub 22. When the nut 8 is tightened, the anti-settling washer 24 is brought into contact with an annular fastening seat surface 27 forming a stepped portion of the shaft 26 via the plate 23, whereby the anti-settling washer 24 and the plate 23 and the hub 22 coupled to the plate 23 by the rivet 11 are fastened to fix the position in the axial direction. That is, the settling prevention washer 24, the plate 23, and the hub 22 are integrated, and torque transmission similar to that of the reference example 1 is achieved. In the second embodiment, the hardness of the plate 23 is made of a general material without being particularly increased. Instead, the hardness of the anti-settling washer 24 is made higher than the hardness of the plate 23 by a surface hardening process or the like. Yes.

The reason why the settling can be avoided is that the same relationship as the relationship between the plate 10 and the fastening seating surface 9 in Reference Example 1 is established between the anti-settling washer 24 and the annular fastening seating surface 27 of the shaft 26, and the settling prevention is achieved. By increasing the hardness of the washer 24, settling of the settling washer 24 due to fastening is prevented. Although the axial force due to fastening is similarly applied between the anti-slip washer 24 and the plate 23, the anti-slip washer 24 has a larger outer diameter than the annular fastening seat surface 27 of the shaft 26. The contact area between the plate 23 and the plate 23 is kept larger, and the contact pressure at the contact surface is kept smaller than the contact pressure between the anti-settling washer 24 and the fastening seat surface 27, and the plate 23 is subjected to the hardening process. Even if it is made of a general material that is not present, settling on the plate 23 side is prevented. In this case, since the surface hardening process only needs to be performed on the anti-sticking washer 24, the cost of the surface hardening process itself can be made lower than that of the first reference example. As described above, also in the second embodiment, a part that requires high accuracy is not required, and the simple construction of the plate 23 and the anti-sticking washer 24 achieves the target anti-sticking while reducing the component cost. Reduction and assembly man-hours can be reduced.

  In the second embodiment, for example, if the anti-slip washer 24 is structured to be positioned in the radial direction between the outer peripheral part of the anti-slip washer 24 and the inner peripheral part of the recess 25 of the hub 22, the threaded part of the shaft 26. 28 is easier to insert.

  The height of the mounting portion of the anti-slip washer 24 formed by the hub 22 and the plate 23 (the distance between the hub 22 and the plate 23 at this portion) is equal to the thickness of the anti-slip washer 24 or the anti-slip washer. By making the thickness greater than 24, it is possible to prevent looseness when the rivet 11 is caulked.

In the reference example 1 and the example 2, the description has been given regarding the fastening between the portion that can function as a torque limiter and the shaft. However, for example, the fastening between the armature boss and the compressor shaft in an electromagnetic clutch, which is another power transmission method. However, the present invention can be similarly applied and the same effect can be obtained.

  The power transmission device according to the present invention can be applied to any power transmission device that transmits a rotational force from a drive source to the shaft of a driven device via a hub, and particularly for a compressor, especially for vehicle air conditioning. It is suitable as a power transmission device used for the compressor of the device.

It is the longitudinal cross-sectional view (FIG. 1 (A)) of the power transmission device which concerns on the reference example 1 of this invention, and the front view (FIG. 1 (B)) of the hub part. It is a top view of the elastic member in the torque transmission part of the power transmission device of FIG. It is a top view of the press member in the torque transmission part of the power transmission device of FIG. It is a longitudinal cross-sectional view of the power transmission device which concerns on Example 2 of this invention. It is the longitudinal cross-sectional view (FIG. 5 (A)) of the conventional power transmission device, and the front view (FIG. 5 (B)) of the hub part.

Explanation of symbols

1, 2 21 Power transmission device 2 Compressor 3 as driven device Pulley 4 Torque transmission portion 5, 22 Hub 6, 26 Shaft 7, 28 Screw portion 8 Nut 9, 27 Fastening seat surface 10, 23 Plate 11 As coupling means Rivets 12 Bolts 13 Elastic members 13a Elastic member arms 14 Pressing members 24 Anti-slip washers 25 Recesses

Claims (7)

In the power transmission device that transmits the rotational force transmitted from the drive source to the shaft of the driven device via the hub, the fastening means that connects the hub and the shaft is a screw portion formed at the end of the shaft A nut that is screwed to the shaft, a plate that is fastened to the shaft by the nut, an anti-slip washer that is interposed between the plate and a fastening seating surface of the shaft, and the plate and the hub A coupling means for increasing the hardness of the anti-settling washer than the hardness of the plate , and the coupling means transmits the rotational force from the driving source to the hub, the plate, and the hub. A rivet that is caulked together with the transmission portion, and the thickness of the anti-stick washer is equal to the distance between the hub and the plate at the portion where the anti-wash washer is mounted. Kamada is smaller than the contact area between the permanent set preventing washer and the plate comprises a being greater than the contact area between the fastening seat of the said permanent set preventing washer shaft Power transmission device. The power transmission device according to claim 1 , wherein the anti-sticking washer is harder than the plate by a surface hardening process. The outer diameter of the settling prevention washer, the being larger than the outer diameter of the fastening seat of the shaft, a power transmission device according to claim 1 or 2. The power transmission device according to any one of claims 1 to 3 , wherein the settling washer is provided in a recess formed in the hub. The power transmission device according to claim 4 , wherein the anti-sticking washer is positioned in a radial direction between an outer peripheral portion of the anti-sticking washer and an inner peripheral portion of the recess. The power transmission device according to any one of claims 1 to 5 , which is used for a compressor. The power transmission device according to claim 6 , which is used for a compressor of a vehicle air conditioner.

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