JP5142857B2 - Vibration absorbing joint and portable brush cutter having the same - Google Patents

Description

  The present invention relates to a vibration absorbing joint that transmits rotation of an output shaft of a prime mover to a transmission shaft and absorbs torsional vibration of the transmission shaft, and a portable brush cutter having the same.

  FIG. 11 shows a conventional example of a portable brush cutter. In the illustrated example, the portable brush cutter 1 ′ is provided with a cutting blade mechanism section 3 including a circular saw blade-shaped cutting blade 4, a gear case (bevel gear unit) 19, a safety cover 5, and the like at the front end of the operation rod 2. At the rear end, with a centrifugal clutch provided with a recoil starter 8 and a fuel tank 9 as a prime mover connected to a rod-like or tubular metal transmission shaft 7 housed in the operation rod 2 for driving the cutting blade 4 An internal combustion engine (small air-cooled two-cycle gasoline engine) 6 is attached.

  Further, a U-shaped handle 10 for operating the cutting blade mechanism 3 to perform the brushing work is attached near the center of the operation rod 2, and left and right ends of the U-shaped handle 10 are respectively left and right. A grip 11 and a right grip 12 are attached.

  In the portable brush cutter 1 ′ having such a configuration, torsional vibration is generated in the transmission shaft 7 due to torque fluctuation, rotation speed fluctuation, and load fluctuation applied to the cutting blade 4 during acceleration and deceleration. More specifically, since the transmission shaft 7 is thin and long (for example, a diameter of 6 mm and a length of about 1500 mm), when the engine speed and the load on the cutting blade 4 increase, the transmission shaft 7 is twisted (rotation delay). Occurs. Further, when the load is suddenly reduced, the transmission shaft 7 causes a springback phenomenon, overruns in the rotational direction and twists. In this way, torque transmission, rotation speed fluctuation, load fluctuation, springback phenomenon, etc. during acceleration / deceleration of the engine cause the transmission shaft 7 to twist or return in the rotational direction and the opposite direction, resulting in torsional vibration.

  Then, the torsional vibration of the transmission shaft 7 propagates to the operator's hand through the operation rod 2 and the handle 10. Such vibration not only shortens the life of the product due to early wear of parts, but also leads to a decrease in operability and an increase in fatigue. It has become.

  As one of the anti-vibration measures, for example, the following Patent Document 1 proposes that a joint member formed of anti-vibration rubber is interposed between the centrifugal clutch and the transmission shaft.

  Further, as another vibration isolation measure, Patent Document 2 below proposes that a one-way clutch be interposed between the centrifugal clutch and the transmission shaft.

  Furthermore, as another anti-vibration measure, it is considered that a torsion coil spring is interposed between the centrifugal clutch and the transmission shaft.

  However, although the conventional anti-vibration measure using the joint member, the one-way clutch, or the torsion coil spring formed of the anti-vibration rubber can provide a temporary anti-vibration effect, it is still not sufficient.

  In particular, when a joint member formed of vibration-proof rubber is used, problems are likely to occur in the durability of the joint member of vibration-proof rubber, and even when a torsion coil spring is used, the torsional direction of the transmission shaft, Since the torsion coil spring is elastically deformed (twisted) indefinitely according to the torsion amount (twist angle), the torsion coil spring is easily damaged, and there is a problem in durability.

  Therefore, the inventors of the present invention can effectively suppress the torsional vibration of the transmission shaft, as described in Patent Document 3 below, in order to solve the above-mentioned problem, as well as durability and the like. We propose a vibration-absorbing joint that can improve the vibration.

  The vibration absorbing joint according to this proposal basically transmits the rotation of the output shaft of the prime mover to the transmission shaft through the torsion coil spring, and absorbs the torsional vibration of the transmission shaft by the torsion coil spring. And a rotation restricting means for restricting the torsion coil spring from being twisted more than a predetermined angle. In a more preferred specific aspect, the torsion coil spring is slidably fitted to a spline male tooth provided on the transmission shaft. A second cylindrical coupling body provided with spline female teeth to be mated, and a first cylindrical coupling which is rotated integrally with the output shaft and slidably fitted into the second cylindrical coupling body Between the body, the second cylindrical coupling body, and the spring receiving portion provided in the first cylindrical coupling body, and one end portion is locked to the locking portion provided in the spring receiving portion. And the other end is provided on the second tubular connector. Is provided with a locked torsion coil spring in the locking unit, the Second cylindrical connecting body and the first tube-like connecting member, it becomes is provided the rotation restricting means.

  In such a proposed vibration absorbing joint, torque fluctuations and rotational speed fluctuations during acceleration / deceleration, as well as torsional vibrations of the transmission shaft caused by load fluctuations and springback phenomenon on the transmission shaft are absorbed by the built-in torsion coil spring. In addition, since the torsion coil spring is restricted from being twisted by a predetermined angle or less by the rotation restricting means, the torsional vibration of the transmission shaft, which is an unpleasant vibration that propagates to the hand of the operator, is effectively prevented. The angle at which the torsion coil spring is twisted (elastic deformation amount) can be reduced as compared with the case where the rotation restricting means is not provided, and as a result, the torsion coil spring is damaged. It becomes difficult to improve durability and the like.

  However, even with such a proposed vibration absorbing joint using a torsion coil spring, stress concentration on the end of the torsion coil spring is inevitable, so it is difficult to expect an excessive life. Since space is required, there is a difficulty in miniaturization.

Conventionally, a vibration absorbing joint using a plurality of compression coil springs has been considered, as can be seen in Patent Document 4 below.
Japanese Utility Model Publication No. 56-53618 JP 2003-88220 A JP 2007-61029 A Japanese Utility Model Publication No. 52-034256

  However, the conventional vibration-absorbing joint using a plurality of compression coil springs is more durable than the one using a torsion coil spring, but it has a large number of parts, is complicated in configuration, and is heavy and heavy. was there.

  Further, in a vibration absorbing joint using a conventional compression coil spring or torsion coil spring, it is virtually impossible to replace each component individually, and when the compression coil spring or torsion coil spring is damaged, Since it is necessary to replace the entire vibration absorbing joint, it is uneconomical and difficult to maintain.

  The present invention has been made to solve the conventional problems as described above, and the object of the present invention is to effectively suppress torsional vibration of the transmission shaft and improve durability. In addition, a vibration absorbing joint that can be replaced easily, such as a coil spring, can be easily maintained, can be rationally simplified, and can be reduced in size and weight, and a portable mowing equipped with the same. To provide a payment machine.

In order to achieve the above object, the vibration absorbing joint according to the present invention basically transmits the rotation of the output shaft of the prime mover to the transmission shaft via the clutch drum and absorbs torsional vibration of the transmission shaft. A drive-side rotary member having a drive-side rotary shaft that serves as an output shaft of the clutch drum, and is disposed coaxially with the drive-side rotary shaft so as to be rotatable relative to the drive-side rotary shaft. A driven-side rotating member having a driven-side rotating shaft provided with a fitting portion for transmitting rotation of the rotating shaft, and the driven-side rotating shaft is configured such that the driven-side rotating shaft (45) is the clutch drum. (34) A plurality of compression coils formed between the driving side rotating member and the driven side rotating member so as to absorb a torsional vibration of the transmission shaft. Each of the springs rotates on the drive side And the drive-side rotating member, the driven-side rotating member, and the plurality of compression coil springs are detachably assembled to each other. It is a feature.

  In a preferred aspect, the driving side rotating member is provided with a driving side abutting portion that abuts and presses against one end side in the length direction of each compression coil spring, and the driven side rotating member has the driving side abutting portion. A spring receiving portion with which the other end in the length direction abuts is provided.

In a preferred embodiment, the drive side contact portion and the spring receiving portion are disposed in the clutch drum, and each compression coil is disposed between the bottom surface portion of the clutch drum and a spring receiving holder having the spring receiving portion. A spring holding surface portion is provided that holds the spring in an arcuate or linear guide shape so as to be extendable and contractible in the length direction.

In a preferred embodiment, the driving-side rotating shaft, as retaining means for said drive-side rotation shaft of the front SL driven-side rotating shaft, removable locking member, such as C-ring is at least one used.

  On the other hand, the portable brush cutter according to the present invention is provided with a cutting blade mechanism portion including a cutting blade and a gear box at the front end of the operating rod, and the cutting blade is provided in the operating rod at the rear end of the operating rod. A prime mover for driving via the transmission shaft is attached, and the vibration absorbing joint having the above-described configuration is interposed between the output shaft of the prime mover and the transmission shaft.

In a preferred aspect of the vibration-absorbing joint according to the present invention configured as described above, a plurality of compression coil springs are concentric with the drive-side rotation shaft, respectively, between the drive-side rotation member and the driven-side rotation member. Since the crack drum is held so as to expand and contract in the direction along the tangent line, the rotation of the crack drum rotates from the driving side abutting portion of the pressing plate rotating integrally with the driving side rotating shaft via the plurality of compression coil springs. It is transmitted to the spring receiving part of the spring receiver holding body, and further transmitted from the driven side rotating shaft that rotates integrally with the spring receiver holding body to the transmission shaft through a fitting portion composed of, for example, spline female teeth → spline male teeth. It is done. Further, the rotation transmission from the transmission shaft to the clutch drum is in the reverse order.

  As described above, the plurality of compression coil springs are held between the driving side rotating member and the driven side rotating member so as to expand and contract in the direction along the tangent line of the driving side rotating shaft, respectively. The compression coil spring acts as a torsional buffer. For this reason, torque fluctuations and rotation speed fluctuations during acceleration / deceleration, as well as torsional vibrations of the transmission shaft caused by load fluctuations and springback phenomenon on the transmission shaft are absorbed by the plurality of compression coil springs. The torsional vibration of the transmission shaft, which is an unpleasant vibration that propagates to a person's hand, can be effectively suppressed.

  In addition, a plurality of compression coil springs are used so that each compression coil spring shares a buffer function (work), and each compression coil spring has a length while maintaining an arcuate or linear guide shape. Since it expands and contracts in the direction, the coil spring is less likely to be damaged and the durability is improved as compared with the case where a torsion coil spring (usually only one) is used.

  Further, the driving side rotating shaft is formed into a cylindrical body so that the driven side rotating shaft can be removably inserted from the inside of the clutch drum, and the driven side rotating shaft is prevented from being detached from the driving side rotating shaft. As a means, at least one detachable locking member such as a C-ring is used, so that the driving side rotating member, the driven side rotating member, and the plurality of compression coil springs can be attached to and detached from each other. Therefore, parts such as a coil spring can be replaced, and maintenance and the like can be easily performed.

  Further, since the compression coil springs are arranged in the clutch drum and the like are reasonably simple, the size and weight can be reduced.

  In addition, since the compression coil spring is used, the rotation restricting means that is necessary when the torsion coil spring is used is not necessary. In this respect, the number of parts can be reduced and the configuration can be simplified. .

  Moreover, in the portable brush cutter provided with the vibration absorbing joint, it is possible to effectively reduce and suppress unpleasant vibration that propagates to the operator's hand through the operating rod and the handle.

Hereinafter, embodiments of the vibration absorbing joint of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing the main part of a portable brush cutter to which an embodiment of the vibration absorption joint according to the present invention is applied, and FIG. 2 is a front half-section of the main part of the vibration absorption joint shown in FIG. FIG. 3 is a rear perspective view in which a part of the main part of the vibration absorbing joint shown in FIG. 1 is disassembled.

  The portable brush cutter 1 shown in the figure has substantially the same overall configuration as the portable brush cutter 1 ′ shown in FIG. 11 described above, and has a cutting blade mechanism including a cutting blade 4 and a gear box 19 at the front end of the operation rod 2. An internal combustion engine 6 with a centrifugal clutch 33 (compact air cooling 2 for driving the cutting blade 4 via a transmission shaft 7 housed in the operation rod 2 at the rear end of the operation rod 2. A cycle gasoline engine) is attached via a fixture 23, and the vibration absorbing joint 30 of this embodiment is interposed between the centrifugal clutch 33 and the transmission shaft 7.

  More specifically, a centrifugal clutch 33 is connected to an output shaft (crankshaft) 31 of the internal combustion engine 6 via a cooling fan 32. The centrifugal clutch 33 is not shown in detail, but a clutch arm 33b rotated by the output shaft 31, a shoe 33c provided at the tip of the clutch arm 33b, and the shoe 33c are frictionally engaged. Thus, the clutch drum 34 that rotates integrally is provided.

  The vibration-absorbing joint 30 of the present embodiment is basically rotatable relative to the drive-side rotary member 30A having the drive-side rotary shaft 35 serving as the output shaft of the clutch drum 34 and the drive-side rotary shaft 35 on the same axis. And two driven coil springs between the driving side rotating member 30A and the driven side rotating member 30B so as to absorb the torsional vibration of the transmission shaft 7. 40, 40 are arranged on the same circumference with an angular interval of 180 ° so as to expand and contract in a direction along the tangent line of the drive side rotation shaft 35, and the drive side rotation member 30A, the driven side rotation member 30B and the two compression coil springs 40, 40 are detachably assembled to each other.

  The drive-side rotary shaft 35 is a cylindrical body into which the driven-side rotary shaft 45 is removably inserted from the inside of the clutch drum 34, and one end side thereof is integrated with the clutch drum 34 by welding or the like. More specifically, the drive-side rotating shaft 35 includes a rear-side small-diameter portion 35c that is externally fitted with a clutch drum 34 (a central hole) and a pressing plate 52 (a central hole), which will be described later, and is joined by welding or the like. Has a front small-diameter portion 35a on which is mounted and held, and an intermediate large-diameter portion 35b between the rear small-diameter portion 35c and the front small-diameter portion 35a. The drive side rotating shaft 35 (the whole vibration absorbing joint 30 as a whole) is rotatably supported by the case member 22 (fan cover and clutch case) via a bearing 26.

  On the other hand, the driven-side rotary shaft 45 is a cylindrical body that is removably inserted into the drive-side rotary shaft 35 from the inside of the clutch drum 34, and the drive-side rotary shaft 45 is disposed at the rear end of the drum 34 side. A rear side on which a flange-like portion 45b abutted and locked to the rear end portion of the shaft 35 and a spring receiving holder 60 comprising a spring receiving plate 62 and a spring holding plate 65, which will be described later, are fitted and joined by welding or the like. A small-diameter portion 45c is provided, and the front side of the flange-like portion 45b is an internal fitting portion 45a that is fitted into the drive side rotation shaft 35 so as to be relatively rotatable.

  Here, the flange 45b functions as a rear retaining means for the driven side rotational shaft 45 with respect to the driving side rotational shaft 35, and is a detachable C-ring as a front side (transmission shaft 7 side) retaining means. 37 is used.

  Further, spline female teeth 7 b (fitting portions) that are slidably fitted to the spline male teeth 7 a provided on the transmission shaft 7 are provided on the inner peripheral portion of the driven side rotation shaft 45.

  As shown in FIG. 4 in addition to FIG. 1, the rear small diameter portion 35c on the drum 34 side of the drive side rotating shaft 35 has one end in the longitudinal direction of each compression coil spring 40, 40. Press with a predetermined thickness having drive side contact portions 52a and 52a that partially contact and press the front half (the rear end side when viewed in the rotational direction P) of the front half (the transmission shaft 7 side when viewed in the spring radial direction) The plate 52 is integrally attached together with the clutch drum 34 by welding or the like.

  In addition, rectangular windows 55A and 55A for holding the compression coil springs 40 and 40 in cooperation with a spring receiving holder 60 of a driven side rotation member 30B described later are provided at the bottom surface portion 34a of the clutch drum 34 at an angle of 180 degrees. A pair of spring holding surface portions 55a are provided which are formed at intervals and project from the rectangular windows 55A and 55A by being bent forward in a cross-sectional shape. The spring holding surface portion 55 a abuts against the center portion of the front side surface of the compression coil springs 40, 40.

  On the other hand, as shown in FIGS. 5 and 6 in addition to FIGS. 1 to 3, a compression coil is provided on the flange-like portion 45 b and the rear small-diameter portion 45 c on the drum 34 side of the driven-side rotating shaft 45. The direction of rotation of two rectangular windows 62A formed at an angular interval of 180 ° with which the other ends in the length direction of the springs 40, 40 (the front end as viewed in the rotation direction P) abut. A spring receiving holder 60 comprising a rectangular spring receiving plate 62 having a predetermined thickness having a front end surface as viewed in P) and a spring holding plate 65 having a spring holding surface portion 65a having an arcuate cross section is integrally formed by welding or the like. It is attached. The spring receiving portion 62a is partially in contact with the rear half of the compression coil spring 40 (on the output shaft 31 side in the spring radial direction).

Accordingly, as shown in FIG. 6, the driven-side rotating member 30B is composed of a driven-side rotating shaft 45 and a spring receiving holder 60, and the compression coil springs 40, 40 are clutch drums of the driving-side rotating member 30A. In the state where the rectangular window 55A and the spring holding surface portion 55a provided on the bottom surface portion 34a of the 34 and the rectangular window 62A and the spring holding surface portion 65a of the spring receiving holder 60 of the driven side rotating member 30B are prevented from being bent. It is held so as to be stretchable in the length direction.

In the vibration absorbing joint 30 of the present embodiment configured as described above, the two compression coil springs 40 and 40 are respectively connected between the driving side rotating member 30A and the driven side rotating member 30B. Are held so as to expand and contract in a direction along the tangent line, so that the two compression coils from the drive side contact portions 52a and 52a of the pressing plate 52 where the rotation of the crack drum 34 rotates integrally with the drive side rotation shaft 35. The spline female teeth 7b → spline male teeth 7a are transmitted from the driven side rotating shaft 45 which is transmitted to the spring receiving portions 62a and 62a of the spring receiving and holding body 60 via the springs 40 and 40 and rotates together with the spring receiving holding body 60. Is transmitted to the transmission shaft 7 via. The rotation transmission from the transmission shaft 7 to the clutch drum 34 is in the reverse order.

As described above, the two compression coil springs 40 and 40 are held between the driving side rotating member 30A and the driven side rotating member 30B so as to expand and contract in the direction along the tangent line of the driving side rotating shaft 35, respectively. As a result, the two compression coil springs 40 and 40 function as a torsional buffer. For this reason, torque fluctuations and rotation speed fluctuations during acceleration / deceleration, as well as torsional vibrations of the transmission shaft caused by load fluctuations and springback phenomenon with respect to the transmission shaft are absorbed by the compression coil springs 40 and 40. The torsional vibration of the transmission shaft, which is an unpleasant vibration that propagates to the hand, can be effectively suppressed.

  Further, two compression coil springs 40, 40 are used so that each compression coil spring 40, 40 shares a buffer function (work), and each compression coil spring 40, 40 is not curved. Since it extends and contracts in the length direction, the coil spring is less likely to be damaged and the durability is improved as compared with the case where a torsion coil spring (usually only one) is used.

  Further, the drive-side rotary shaft 35 is formed in a cylindrical shape so that the driven-side rotary shaft 45 can be removably inserted from the inside of the clutch drum, and the driven-side rotary shaft 45 is connected to the drive-side rotary shaft 35. As a retaining means, a C-ring 37 is used on the front side of the clutch drum 34, and the driving side rotating member 30A, the driven side rotating member 30B, and the compression coil springs 40, 40 are detachably assembled. Therefore, parts such as a coil spring can be replaced, and maintenance and the like can be easily performed.

  In addition, since the compression coil springs 40, 40 are arranged in the clutch drum 34 and the like can be reasonably simply combined, a reduction in size and weight can be achieved.

  In addition, since the compression coil spring is used, the rotation restricting means that is necessary when the torsion coil spring is used is not necessary. In this respect, the number of parts can be reduced and the configuration can be simplified. .

  Moreover, in the portable brush cutter 1 provided with the vibration absorbing joint, it is possible to effectively reduce and suppress unpleasant vibrations that propagate to the operator's hand through the operating rod and handle.

  In the above embodiment, two compression coil springs are used, but it is needless to say that three or more compression coil springs may be used.

  8, 9 and 10 show a vibration absorbing joint 70 using three compression coil springs. The basic configuration of the vibration absorbing joint 70 of this embodiment is the same as that of the vibration absorbing joint 30 of the above embodiment, but changes are made depending on the number of compression coil springs used. That is, the rear small diameter portion 35c on the drum 34 side of the driving side rotating shaft 35 of the driving side rotating member 70A includes three compression coil springs 80, as can be understood by referring to FIG. 9 in addition to FIG. Drive-side contact portion 82a that partially contacts and presses the front half (the transmission shaft 7 side as viewed in the spring radial direction) of one end side in the length direction of 80 and 80 (the rear end side as viewed in the rotation direction P). , 82a and 82a having a predetermined thickness and a trifurcated pressing plate 82 are integrally attached together with the clutch drum 34 by welding or the like.

  Further, rectangular windows 85A, 85A, 85A for holding the compression coil springs 80, 80, 80 in cooperation with the spring receiving holder 90 of the driven side rotating member 70B are 120 degrees on the bottom surface portion 34a of the clutch drum 34. A pair of spring holding surface portions 85a that are bent forward and projecting in a cross-sectional C shape from the rectangular windows 85A, 85A, 85A are provided. The spring holding surface portion 85 a abuts against the front side center portion of the compression coil springs 80, 80, 80.

  On the other hand, as shown in FIG. 10 in addition to FIG. 8, the compression coil springs 80, 80, 80 are provided on the flange-like portion 45 b and the rear small diameter portion 45 c on the drum 34 side of the driven side rotation shaft 45. Spring receiving portions 92a, 92a, 92a (the rotation direction P of the three rectangular windows 92A formed at an angular interval of 120 °) with which the other end in the length direction (the front end side when viewed in the rotation direction P) abuts. A spring receiving holder 90 having a spring holding surface portion 95a having a circular arc cross section provided at the center of each rectangular window 92A. Etc. are attached integrally. The spring receiving portion 92a partially abuts the rear half of the compression coil spring 80 (on the output shaft 31 side in the spring radial direction).

Accordingly, the compression coil springs 80 are rectangular windows 85A and spring holding surface portions 85a provided on the bottom surface 34a of the clutch drum 34 of the driving side rotating member 70A and the rectangular windows of the spring receiving and holding body 90 of the driven side rotating member 70B. 95A and the spring holding surface portion 95a are held so as to be extendable and contractible in the length direction.

  Thus, even when three compression coil springs are used, substantially the same operational effects as in the above embodiment can be obtained.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited to the said embodiment, For example, when wanting to extend the full length of the compression coil spring with which the limited space is mounted to the maximum In the embodiment, the guide shape of the spring storage portion in which the storage members of the spring are arranged in a rectangle along the tangent line of the drive side rotation shaft is arranged along the inner circumferential surface of the clutch drum concentric with the drive side rotation shaft. The length of the compression coil spring is changed to that of the clutch drum by changing to a guide shape arranged on the fan surface and applying a compression coil spring that has a small spring constant and can be easily bent, or a compression coil spring having an arcuate free shape itself. It can be extended to a length close to the semicircular circumference of the inner peripheral surface. In addition, when it is desired to adjust the curvature of the compression coil spring accompanying the rotational movement, an appropriate inclination can be added in advance to the contact surface and the holding surface of the spring. Various changes can be made in the design without departing from the spirit of the invention.

Sectional drawing which shows the principal part of the portable brush cutter to which embodiment of the vibrational absorption joint which concerns on this invention was applied. FIG. 2 is a half cross-sectional perspective view showing a main part of the vibration absorbing joint shown in FIG. 1. The rear perspective view which decomposes | disassembles and shows a part in the principal part of the vibrational absorption joint shown by FIG. The rear view with which it uses for description of the drive side rotation member shown by FIG. The rear view with which it uses for description of the driven side rotation member shown by FIG. The perspective view which shows the driven side rotation member shown by FIG. The perspective view which shows the assembly state of the vibrational absorption joint shown by FIG. The rear perspective view which decomposes | disassembles and shows a part in the principal part of the portable brush cutter to which other embodiment of the vibration absorption coupling which concerns on this invention was applied. The rear view with which it uses for description of the drive side rotation member shown by FIG. The rear view with which it uses for description of the driven side rotation member shown by FIG. The perspective view which shows an example of the conventional portable brush cutter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Portable brush cutter 2 Operating rod 3 Cutting blade mechanism 4 Cutting blade 6 Internal combustion engine (prime mover)
7 Transmission shaft 7a Spline male teeth 7b Spline female teeth 30 Vibration absorbing joint 30A Drive side rotary member 30B Drive side rotary member 31 Output shaft 33 Centrifugal clutch 34 Clutch drum 35 Drive side rotary shaft
37C ring (prevention means)
40 Compression coil spring 45 Driven side rotating shaft
52 pressing plate 52a driving side contact portion 55a spring holding surface portion 60 spring receiving holder 62 spring receiving plate 62a spring receiving portion 65 spring holding plate 65a spring holding surface portion 70 vibration absorbing joint 70A driving side rotating member 70B driven side rotating member 80 compression Coil spring 82a Driving side contact portion 85a Spring holding surface portion 90 Spring receiving holder 92a Spring receiving portion 95a Spring holding surface portion O Center (rotation) axis

Claims (5)

The vibration absorbing joint is adapted to transmit the rotation of the output shaft (31) of the prime mover (6) to the transmission shaft (7) through the clutch drum (34) and to absorb the torsional vibration of the transmission shaft (7). (30)
A drive-side rotating member (30A) having a drive-side rotating shaft (35) serving as an output shaft of the clutch drum (34), and coaxially arranged with the driving-side rotating shaft (35) so as to be relatively rotatable. A driven side rotating member (30B) having a driven side rotating shaft (45) provided with a fitting portion (7b) for transmitting the rotation of the driving side rotating shaft (35) to the transmission shaft (7) ; With
The driving side rotating shaft (35) is a cylindrical body into which the driven side rotating shaft (45) is detachably inserted from the inside of the clutch drum (34).
In order to absorb the torsional vibration of the transmission shaft (7), a plurality of compression coil springs (40) are provided between the driving side rotating member (30A) and the driven side rotating member (30B), respectively. It is arranged so as to expand and contract in a direction along a concentric circle or tangent to the side rotation shaft (35),
The vibration absorbing joint, wherein the driving side rotating member (30A), the driven side rotating member (30B), and the plurality of compression coil springs (40) are detachably assembled to each other.   The driving side rotating member (30A) is provided with a driving side abutting portion (52a) that abuts and presses against one end in the length direction of each compression coil spring (40), and the driven side rotating member (30B). The vibration absorbing joint according to claim 1, wherein a spring receiving portion (62a) with which the other end in the length direction of each compression coil spring (40) abuts is provided. The drive side contact portion (52a) and the spring receiving portion (62a) are disposed in the clutch drum (34), and the bottom surface portion (34a) of the clutch drum (34) and the spring receiving portion (62a) are connected. Spring holding surface portions (55a, 65a, 65a, 65a, 65) that hold the compression coil springs (40) in an arcuate or linear guide shape so as to be extendable and contractable in the length direction between the spring receiving holders (60). ...) is provided, The vibration-absorbing joint according to claim 2. The driving side rotational shaft (35), as a retaining means for the pre-Symbol the driving side rotational shaft of the driven side rotary shaft (45) (35), C-ring (37) detachable locking member is at least one such The vibration absorbing joint according to any one of claims 1 to 3, wherein two are used. A cutting blade mechanism (3) including a cutting blade (4) and a gear box (19) is provided at the front end of the operating rod (2), and the cutting blade (4) is provided at the rear end of the operating rod (2). A portable brush cutter (1) to which is attached a prime mover (6) for driving through a transmission shaft (7) incorporated in the operating rod (2),
The vibration absorption joint (30) according to any one of claims 1 to 4 is interposed between the output shaft (31) of the prime mover (6) and the transmission shaft (7). A portable brush cutter.

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