JP2007100923A - Power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmission device utilizing screw fastening, wherein the trouble of being unable to cut off power even during the operation of a torque limiter is avoided. <P>SOLUTION: The power transmission device 10 comprises rotatable parts 1, 2 to which rotation driving force is transmitted from a driving source, and a power cutoff member 3 for cutting off the transmission of overtorque between each rotatable part and a rotating shaft 4 of a driven device. The power cutoff member is screw-fastened to the rotating shaft for integral rotation. Each rotatable part is installed to be held between the power cutoff member and the rotating shaft. A plate spring 8 is also installed between the power cutoff member and the rotatable part. Besides, at the front end of the rotating shaft, a caulked portion 204a is provided for preventing fall-off of a portion of the power cutoff member. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power transmission device, and more particularly, is suitably used by being incorporated into a compressor for a vehicle car air conditioner that is operated from an external power source such as an engine via a belt or the like.

  A refrigerant compressor of a car air conditioner for a vehicle is driven from an external power source such as an engine via a belt, a pulley, etc., but an electromagnetic clutch is inserted between them to disconnect the engine and the compressor. May be. However, if the electromagnetic clutch is not inserted, the cost is reduced and the electromagnetic clutch is often omitted. In this case, in a power transmission device for a compressor for a car air conditioner that is operated from an external power source such as an engine via a belt or the like, a torque limiter for avoiding problems such as belt breakage when the compressor is burned. Is installed.

  Some torque limiters use screw joints as part of the power transmission path, and use excessive axial force generated in the screw joints due to excessive torque when the compressor is burned (for example, Patent Documents). 1). As described above, in the conventional power transmission device that transmits power to the compressor, a power shut-off device (torque limiter) is used to avoid problems such as belt breakage for power transmission when the compressor seizes. is set up. A power shut-off device (torque limiter) having a structure in which a part of the power transmission part is screw-fitted has been proposed in the past, and the torque limiter method using this screw-fitting is an excessively large amount generated when the compressor is burned. This is a method of breaking the power transmission path by breaking a part of the power transmission path by using an excessive axial force generated in the screw fitting portion by torque. That is, this torque limiter system uses an excessive torque generated by the seizure phenomenon of the compressor and has a structure in which the power shut-off member is divided by a pulling force by an excessive axial force generated by screw fastening. However, when the power cut-off member is broken, depending on the shape of the broken portion, the screw portion of the power cut-off member may be retightened. In this case, there is no gap space formed between the power shut-off member and the seat surface of the inner hub that houses the power shut-off member, and the seat surface of the inner hub serves as the screw portion of the power shut-off member and the shaft of the compressor. There was a problem that the power could not be cut off because it was sandwiched between the end faces.

  A conventional power transmission device 50 having the above problem will be described with reference to FIGS. FIG. 8 is a partial side sectional view of a conventional embodiment of a power transmission device using screw fastening, and FIGS. 9 and 10 show that a torque limiter (power cutoff member) of the power transmission device 50 of FIG. It is a fragmentary sectional side view which shows two states after fracture | rupture. The configuration of the power transmission device 50 shown in FIG. 8 is such that the rotation of a power source such as an engine is transmitted to a pulley by a belt or the like and further transmitted to the power transmission device 50 in which the pulley is assembled. The configuration of the power transmission device 50 is basically the same as that of the power transmission device of the present invention shown in FIG. 1 and the like and will be described later, and will not be described in detail here. In the power transmission device 50, the power is first transmitted to the hub, and then transmitted in the order of the power shut-off member and the rotation shaft of a compressor or the like screwed to the power shut-off member.

  In the conventional power transmission device 50 of FIG. 8, the screw portion 303 of the power shut-off member 3 is screwed to the screw portion 402 of the rotary shaft 4 and moved in the direction of the driven device or the rotary shaft (rightward in FIG. 8). Let them assemble. Thereby, the inner hub 204 of the hub 2 is sandwiched between the power cutoff member 3 and the rotating shaft 4 and compressed. In this way, due to the axial compression force generated by the screw coupling between the power cut-off member 3 and the rotary shaft 4, the contact surface between the power cut-off member 3 and the inner hub 204 and the contact surface between the inner hub 204 and the rotary shaft 4 are used. A frictional force is formed. Due to this frictional force, the power shut-off member 3 and the hub 2 rotate together with the rotating shaft 4.

  FIG. 9 and FIG. 10 are diagrams for explaining the configuration after the power cut-off member 50 is operated and the power cut-off member 3 is broken in the conventional embodiment. In FIG. 9, when the power cut-off member 3 breaks at the breakage portion 301, fracture surfaces 308 and 309 are formed, and the power cut-off member is divided into a flange portion 302 and a screw member 306. The fracture surfaces 308 and 309 are not necessarily flat. Therefore, in FIG. 9, when the flange-side fracture surface 308 rotates the screw-member-side fracture surface 309, the screw member 306 of the power cut-off member advances toward the compressor (driven device) side. Due to this phenomenon, the gap B9 formed in FIGS. 8 and 9 disappears, the end surface 307 of the screw member 306 of the power cut-off member interferes with the anti-contact surface 204e of the hub, and the hub seat 204c is further screwed by the axial force. The member 306 is sandwiched between the end surface 307 of the member 306 and the shaft contact surface 403 on the rotating shaft side, and power is transmitted. That is, even if the power cut-off member 3 is operated and broken, there is a problem that the power cannot be cut off and the power is retransmitted to the driven device such as the rotary shaft 4 and the compressor.

JP 2003-206950 A

  The present invention has been made in view of the above-described circumstances, and provides a power transmission device capable of avoiding a problem that power cannot be shut off even when the torque limiter is operated in the torque limiter system using the screw fastening. Objective.

  According to the first aspect of the present invention, the power transmission device (10) includes a rotatable rotating portion (1, 2) to which a rotational driving force from a driving source is transmitted in order to achieve the above-described object. And a power shut-off member (3) for shutting off transmission of excessive torque between the rotating portion and the rotating shaft (4) of the driven device. The power cut-off member is screwed to the rotation shaft and can be rotated together. The rotating part is installed so as to be sandwiched between the power cut-off member and the rotating shaft. An elastic member (8) is further provided between the power shut-off member and the rotating part.

  With this configuration, in the torque limiter system using the screw fastening, since the elastic member (8) is installed between the power shut-off member and the rotating portion, the power shut-off member is operated and divided. Then, the elastic member acts by moving the part of the divided power cut-off member away from the rotating part by its elastic force, and prevents each part of the divided power cut-off member from interfering with each other. As a result, the problem that the power cannot be shut off due to the re-fastening of the power break portion is avoided, and the power can be cut off reliably when the compressor is burned.

According to a second aspect of the present invention, when the power shut-off member is activated in the form according to the first claim, the power shut-off member is not screw-coupled to the rotating shaft (302). ) And a second portion (306) screwed to the rotating shaft. Further, at that time, the first portion is configured to be freely movable with respect to the second portion.
According to this embodiment, since the first portion is freely movable with respect to the second portion, it is possible to avoid the first portion from interfering with the second portion when the power cut-off member is operated, and accordingly, the power Even if the blocking member breaks, it is possible to avoid the problem that the power cannot be blocked.

According to a third aspect of the present invention, in the form according to the second aspect, the first portion is configured to be freely movable in the axial direction of the rotating shaft. To do.
According to this embodiment, the first portion can move in the axial direction and can be separated from the second portion, so that the first portion can be prevented from interfering with the second portion.

According to a fourth aspect of the present invention, in the form according to any one of the first to third aspects, the elastic force of the elastic member acts on the power cutoff member in the axial direction of the rotating shaft. It is characterized by doing.
According to this embodiment, since the elastic force of the elastic member acts in the axial direction with respect to the power cut-off member, when the power cut-off member is activated and divided, a part of the divided power cut-off member is moved in the axial direction. Therefore, it is possible to avoid the problem that the power cannot be cut off even if the power cut-off member breaks.

According to a fifth aspect of the present invention, in the form according to any one of the second to fourth aspects, when the power cut-off member is operated, the elastic member has the first portion as the first portion. It acts on the first part so as to be away from the two parts.
According to this embodiment, since the elastic member acts so that the divided first portion is separated from the second portion, the first portion and the second portion can be prevented from interfering with each other. Even if the blocking member breaks, it is possible to avoid the problem that the power cannot be blocked.

According to the sixth aspect of the present invention, in the form according to any one of the first to fifth aspects, the stopper means (204a, 1000) is provided so as to prevent the power shut-off member from falling off. . An interval (204b) is provided between the stopper means and the power cut-off member.
According to the present embodiment, the stopper means prevents the divided part (first part) of the power shut-off member from falling off from the power transmission device, and the interval is provided. It can be avoided that the two portions interfere with each other.

According to a seventh aspect of the present invention, in the form according to any one of the first to sixth aspects, the elastic member is a disc spring, rubber, or coil spring.
According to this form, the form which actualizes an elastic member more is disclosed.

According to an eighth aspect of the present invention, in the form according to any one of the first to seventh aspects, the rotating portion includes a hub (2). The hub is connected to the power cut-off member, and is further installed so as to be sandwiched between the power cut-off member and the rotating shaft.
According to the present embodiment, the present invention is further embodied by the configuration in which the rotating unit includes the hub.

According to a ninth aspect of the present invention, in any one of the first to eighth aspects, the vehicle is connected to a compressor of a vehicle car air conditioner as a driven device. .
According to this form, the form which actualizes the use of this invention more is disclosed.
In the above description of the present invention, symbols or numbers in parentheses () are attached to show correspondence with the embodiments described below.

  Embodiments of a power transmission device according to the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a schematic side sectional view of a first embodiment of a power transmission device according to the present invention, and FIG. 2 is a partially enlarged side sectional view around a power cutoff member of FIG. 3 and 4 are partially enlarged side sectional views of two states in which the power cut-off member is broken by operating in the first embodiment. The reference numerals of the element parts in FIGS. 1 to 4 correspond to the reference numerals of the same element parts in the conventional examples of FIGS.

  A power transmission device 10 according to the first embodiment of the present invention shown in FIG. 1 is used in a car air conditioner for a vehicle, and transmits the rotational force of an external drive source such as an engine to a compressor of the car air conditioner. It is a device and comprises a power cut-off member (torque limiter) 3. In the power transmission device 10, rotational power from the outside is transmitted to the pulley 1 via a belt (not shown) or the like, and the uneven portion 201 made of an elastic member installed on the outer periphery of the hub 2 is provided on the uneven portion 101 of the pulley. Is transmitted to the inner hub 204 of the hub 2. For example, the pulley-side uneven portion 101 and the hub-side uneven portion 201 may be configured to be fitted by a plurality of uneven portions corresponding to each other. The power is further transmitted from the hub 2 to the power shut-off member 3, but in the present embodiment, the inner hub 204 and the power shut-off member 3 are in the fitting portion of the inner hub and the fitting portion of the power shut-off member. Inlay mating. Here, the pulley 1 and the hub 2 correspond to a rotating portion in claims.

  Torque transmission between the inner hub 204 and the power cut-off member 3 is not shown, but for example, a hexagonal fitting portion that is the outer periphery of the flange portion 302 of the power cut-off member 3 and a hexagonal fitting portion of the hub 2 It is not shown in this embodiment, but it is fastened with a non-circular shape such as a square, two-sided width, octagon, decagon, twelve, etc. Or may be fastened with screws installed on both sides to transmit torque. The power transmitted from the hub 2 to the power cut-off member 3 is transmitted from the power cut-off member 3 to a rotary shaft 4 of a compressor (not shown) that is screwed to the power cut-off member 3 to rotate the compressor.

  In FIG. 2, the inner hub 204 and the power shut-off member 3 are fastened by an axial force generated by being screwed by a screw portion 303 of the power shut-off member and a screw portion 402 of the rotary shaft 4 of the compressor. The fastening axial load is supported by the hub seat 204c of the inner hub 204, and the hub contact surface 204d of the hub 2 and the shaft contact surface 403 of the rotary shaft 4 are in contact with each other. A gap B9 is set between the end surface 307 of the power shut-off member 3 on the compressor (or rotating shaft) side and the hub non-contact surface 204e of the hub seat 204c of the inner hub 204, and faces each other via the gap B9. ing. A disc spring 8 is installed on the back surface 305 of the flange portion 302 of the power shut-off member 3 (between the flange portion 302 of the power shut-off member 3 and the inner hub 204). A caulking portion 204a (a stopper means in claims) for preventing the direction from coming off is set, and a gap A (interval) 204b is set between the flange portion 302 and the caulking portion 204a.

  3 and 4 are views for explaining a state after the power cut-off member (torque limiter) 3 of FIG. 2 according to the first embodiment is operated. In FIG. 2, when the power cut-off member 3 operates and breaks at the breaking portion 301, the power cut-off member 3 is separated into a flange portion 302 and a screw member 306 (a first portion and a second portion in the claims). Since the surface of the fractured portion 301 is not necessarily flat as in the conventional example, the fracture surface 308 on the flange side may contact the fracture surface 309 on the screw member side and interfere with each other. At this time, the divided screw member 306 is rotated to advance in the axial direction (compressor side). However, since the gap A204b is set between the flange portion 302 and the caulking portion 204a, the flange portion 302 can be easily moved by the gap A204b. By the repulsive force of the disc spring 8 installed at 305, the flange portion 302 is pushed and moved in the direction toward the distal end portion of the rotating shaft 4 (leftward in FIG. 2) until it contacts the crimping portion 204a (the screw member 306 is moved). (It is not rotated because it is screw-coupled to the rotating shaft 4) (see FIG. 4).

  When the power cut-off member (torque limiter) 3 is operated, the flange portion 302 loses the restraining force. Therefore, the flange portion 302 is pushed forward (in the direction of the rotating shaft tip) by the disc spring 8 and the inner hub 204 is caulked. Move to section 204a. In this state, the flange portion 302 moves away from the fracture surface 309 of the screw member 306 of the divided power shut-off member 3, so that the power is surely shut off without being coupled again with the screw member 306 of the power shut-off member. . In the present embodiment, the movement of the screw member 306 in the direction in which the hub 2 is sandwiched is restricted, the gap B9 is secured without sandwiching the hub seat 204c, and the hub seat 204c is idled without being restricted in rotation. It becomes possible. Since the hub seat 204c of the inner hub 204 is not sandwiched between the screw member 306 of the power cut-off member 3 and the stepped shaft contact surface 403 of the rotary shaft 4, the screw connection between the power cut-off member 3 and the rotary shaft 4 is achieved. Does not act on the inner hub 204, so the power is completely cut off.

FIG. 5 is a partially enlarged side sectional view corresponding to FIG. 2 of the power transmission device according to the second embodiment of the present invention. In the first embodiment, a disc spring is installed on the back surface of the flange portion 302. However, the present invention is not limited to this, and an elastic member other than the disc spring, for example, an elastic member 8 such as rubber is provided. May be installed. Although not shown, when the coil spring or the like is in a free state, the same effect can be obtained with materials and parts of the extending mechanism.
Since the configuration of the second embodiment other than the above is basically the same as that of the first embodiment, the description thereof is omitted.

FIG. 6 is a partially enlarged side sectional view corresponding to FIG. 2 of the power transmission device according to the third embodiment of the present invention. In the present embodiment, the stopper structure (means) prevents the flange portion 302 from coming off in the axial direction by the rivet 1000, not the crimp structure by the crimp portion 204a of the first embodiment. The same effect can be obtained by this configuration.
Since the configuration of the third embodiment other than the above is basically the same as that of the first embodiment, the description thereof is omitted.

FIG. 7 is a partially enlarged side sectional view corresponding to FIG. 2 of the power transmission device according to the fourth embodiment of the present invention. In the present embodiment, the stopper structure is not the caulking structure and the rivet structure of the first and second embodiments, but is a stopper structure in which the flange portion 302 is prevented from coming off in the axial direction by the bolt 1000. The same effect can be obtained by this configuration.
Since the configuration of the fourth embodiment other than the above is basically the same as that of the first embodiment, the description thereof is omitted.

  With reference to the drawings of the second to fourth embodiments described above, ie with reference to FIGS. 5 to 7, from FIG. 5 which is the same as or similar to the element parts of the first embodiment disclosed in FIGS. The element part 7 is designated by the same reference numeral.

Next, effects and operations of the above embodiment will be described.
The following effects can be expected from the power transmission device according to the first embodiment of the present invention.
・ In the torque limiter system using screw fastening, the inner hub that transmits power from the pulley is coupled to the inner hub in the rotational direction, and in the axial direction, only the gap can be moved by the caulking stopper means. In the structure including the installed power cut-off member, the elastic member of the disc spring is installed on the back surface of the flange portion of the power cut-off member, so that when the torque limiter is operated, the flange portion is separated from the screw member. As a result, it can be separated by a repulsive force of a spring or the like, and as a result, the problem that the power cannot be shut off due to re-fastening of the power breaking portion is avoided, and the power can be cut off reliably when the compressor is burned.

  Effects similar to those of the first embodiment can be expected from the power transmission devices of the second to fourth embodiments of the present invention.

In the above embodiment, the example in which the present invention is used as a power transmission device for a compressor of a car air conditioner for a vehicle is shown. However, the present invention may be applied to other uses. It is not limited to car air conditioners.
In the embodiment described above or shown in the accompanying drawings, the power of the drive source has been described as being transmitted via a belt and a pulley, but the present invention is not limited to this, For example, power may be transmitted via another mechanism such as a gear.

  In the embodiment described above or shown in the accompanying drawings, for example, in the first and second embodiments, the disc spring 8 and the caulking portion 204a and the elastic member 8 and the caulking portion 204a are combined. However, the configuration may be such that the elastic member 8 and the rivet 1000 of the third embodiment are combined, that is, various combinations of an elastic member such as a disc spring and stopper means such as a caulking portion are adopted. May be.

  The above-described embodiment is an example of the present invention, and the present invention is not limited by the embodiment, but is defined only by matters described in the claims, and other embodiments than the above are also possible. It can be implemented.

FIG. 1 is a schematic side sectional view of a first embodiment of a power transmission device according to the present invention. FIG. 2 is a partially enlarged side sectional view of the periphery of the power shut-off member of FIG. FIG. 3 is a partially enlarged side sectional view showing a state in which the power cut-off member is broken by operating in the first embodiment, and shows a state immediately after the break. FIG. 4 is a partial enlarged side cross-sectional view of the first embodiment in a state where the power cut-off member is activated and broken, and shows a state in which the flange portion 302 has advanced to the caulking portion 204a. FIG. 5 is a partially enlarged side sectional view similar to FIG. 2 of the second embodiment of the power transmission device according to the present invention. FIG. 6 is a partially enlarged side sectional view similar to FIG. 2 of the third embodiment of the power transmission device according to the present invention. FIG. 7 is a partially enlarged side sectional view similar to FIG. 2 of the fourth embodiment of the power transmission device according to the present invention. FIG. 8 is a partially enlarged side sectional view similar to FIG. 2 of a conventional power transmission device. FIG. 9 is a partially enlarged side cross-sectional view of the conventional example of FIG. 8 in a state where the power cut-off member is activated and broken, and shows a state immediately after the break. FIG. 10 is a partially enlarged side cross-sectional view of the conventional example of FIG. 8 in a state where the power shut-off member is activated and broken, and shows a state where the screw member has advanced to the hub seat.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pulley 101 (Pulley side) uneven part 2 Hub 201 (Hub side) uneven part 204 Inner hub 204a Caulking part 204b Gap A
204c Hub seat 204d Hub contact surface 3 Power cut-off member 302 Flange portion 303 Screw portion 306 Screw member 307 End surface 4 Rotating shaft 402 Screw portion 403 Shaft contact surface 8 Disc spring (elastic member)
9 Gap B
10 Power transmission device

Claims (9)

A rotatable rotating part (1, 2) to which a rotational driving force from a driving source is transmitted;
A power shut-off member (3) for shutting off transmission of excessive torque between the rotating part and the rotating shaft (4) of the driven device, wherein the power shut-off is capable of rotating integrally with the rotating shaft. A member,
In the power transmission device (10) comprising:
The rotating portion is installed so as to be sandwiched between the power shut-off member and the rotating shaft, and further includes an elastic member (8) installed between the power shut-off member and the rotating portion. A power transmission device comprising: When the power cut-off member is activated, the power cut-off member is divided into a first portion (302) that is not screwed to the rotating shaft and a second portion (306) that is screwed to the rotating shaft. The first portion is configured to be freely movable with respect to the second portion when the power cut-off member is operated. Item 4. The power transmission device according to Item 1.   The power transmission device according to claim 2, wherein the first portion is configured to be freely movable in an axial direction of the rotation shaft.   4. The power transmission device according to claim 1, wherein the elastic force of the elastic member acts on the power shut-off member in an axial direction of the rotating shaft. 5.   The elastic member acts on the first portion so that the first portion is separated from the second portion when the power cut-off member is operated. The power transmission device according to any one of claims.   Stopper means (204a, 1000) is further provided, and the stopper means prevents the power shutoff member from falling off when the power shutoff member is actuated, and the stopper means and the power shutoff member The power transmission device according to any one of claims 1 to 5, wherein a space (204b) is provided between the power transmission devices.   The power transmission device according to any one of claims 1 to 6, wherein the elastic member is a disc spring, rubber, or a coil spring. The rotating part includes a hub (2),
The hub is connected to the power shutoff member;
The power transmission device according to any one of claims 1 to 7, wherein the hub is installed so as to be sandwiched between the power shut-off member and the rotating shaft.   The power transmission device according to any one of claims 1 to 8, wherein the power transmission device is connected to a compressor of a car air conditioner for a vehicle as a driven device.

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