JPH0711550Y2 - Anti-vibration device for power brush cutter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a vibration isolator for a power brush cutter, and more particularly to a vibration isolator with improved assemblability in a power brush cutter.

[Prior Art] In a power brush cutter, there is a problem of vibration transmitted from a power unit attached to one end side of an outer pipe via a clutch device to the outer pipe.

Japanese Utility Model Application Laid-Open No. 58-24131 discloses transmission from a power unit to an outer pipe by interposing a connecting member including a cylindrical rigid body and a cylindrical elastic body between the clutch case of the clutch body and the outer pipe. A vibration damping device for a power brush cutter that alleviates vibration is disclosed.
In this vibration isolator, the cylindrical rigid body is fitted and inserted into the outer tube and the clutch case on both sides, and is fixed to the outer tube by a screw at the outer tube side fitting insertion portion, and the cylindrical elastic body is made of the cylindrical rigid body. It is interposed between and fixed to the outer circumference of the clutch case side fitting portion and the inner circumference of the clutch case. The vibration transmitted from the power unit through the clutch case is absorbed by the elastic deformation of the tubular elastic body, and is prevented from being transmitted to the clutch case side fitting insertion portion of the tubular rigid body. Thereby, the vibration transmitted from the power unit to the outer pipe can be suppressed.

Further, the tubular elastic body in Japanese Utility Model Laid-Open No. 58-24131 has a flange portion on the outer tube side, and the clutch case is adapted to fit into the tubular elastic body until it comes into contact with the flange portion.

[Problems to be solved by the device]

The problems of the vibration isolator of the power brush cutter disclosed in Japanese Utility Model Laid-Open No. Sho 58-24131 are as follows.

(A) A plurality of screws are used to fix the outer tube side fitting insertion portion of the tubular rigid body of the connecting member to the outer tube, and the screw insertion holes and the screw holes are fitted into the outer tube and outer tube side fitting. Machining the insertion portion requires high accuracy and requires an insertion hole and a screw hole for each screw, which leads to complication and complication of the machining.

(B) During work, a large twist or bending load acts on the outer pipe, so the insertion hole and the screw hole processed in the outer pipe and the outer pipe side fitting insertion portion become notches for stress concentration, resulting in fatigue and cracking. Cause

(C) Since the outer tube side fitting insertion portion of the tubular rigid body needs to have a smaller diameter than the outer tube, there is a slight gap between the outer tube and the outer tube, and due to this gap, the outer tube and the tubular shape are cylindrical. Relative displacement causes mutual wear with the rigid body, and promotes rattling.

(D) Since the clutch case needs to be fitted to the tubular elastic body until it comes into contact with the flange portion of the tubular elastic body, high accuracy in terms of dimensions is required. Further, the collar portion complicates the shape of the tubular elastic body, and complicates the manufacturing.

An object of the invention of claim 1 is to provide an anti-vibration device for a power brush cutter that can solve the problems (a) to (c).

An object of the invention of claim 2 is to provide an anti-vibration device for a power brush cutter capable of solving the above-mentioned problem (d).

[Means for Solving the Problems]

The invention will be described using the reference numerals of the drawings corresponding to the embodiments.

In the power brush cutter (10) which is the premise of claim 1, the rotational power of the power section (12) is generated by the clutch body (26) and the transmission shaft (3).
It is transmitted to the cutting blade (20) through the clutch body (2).
6) and transmission shaft (34) are clutch case (28) respectively
And is covered by the outer tube (14). Connection member (40)
Is a cylindrical rigid body (42) fitted into the outer tube (14) and the clutch case (28) on both sides and fixed to the outer tube (14) at the outer tube side fitting part (46). The tubular rigid body (42) includes a tubular elastic body (44) interposed between the outer periphery of the clutch case side fitting insertion portion (48) and the inner periphery of the clutch case (28) and fixed to the both. There is.

And, in the vibration isolator of the power brush cutter (10) according to claim 1,
The outer pipe side fitting insertion part (46) of the cylindrical rigid body (42) has a knurled groove (50) on the outer peripheral surface, and is fixed to the outer pipe (14) by press fitting into the inner periphery of the outer pipe (14). ing. The outer tube (14) and the clutch case (28) are axially spaced so as not to contact each other.

In the vibration isolator of the power brush cutter (10) of the second aspect, the outer peripheral surface of the cylindrical elastic body (44) is a cylindrical side surface over the entire axial direction. That is, the cylindrical elastic body (44) has an outer peripheral surface of a cylindrical side surface from one end to the other end in the axial direction, and no radial protrusion such as a collar portion or a protrusion is present on the outer peripheral surface. The screw (51) penetrates the tubular elastic body (44) in the radial direction to fix the clutch case (28) and the clutch case side fitting insertion portion (48) of the tubular rigid body (42).

[Action]

In the invention of claim 1, the outer tube side fitting insertion part (46) is knurled by press-fitting the outer tube side fitting insertion part (46) of the cylindrical rigid body (42) into the inner peripheral side of the outer tube (14). It is inserted into the outer tube (14) while being compressed and deformed so as to fill the (50).

The vibration of the power unit (12) is transmitted to the outer peripheral side of the cylindrical elastic body (44) via the clutch case (28), and the cylindrical elastic body (44)
Receives the vibration, elastically deforms, absorbs the vibration, and suppresses the transmission of the vibration to the clutch case side fitting insertion part (48) of the tubular rigid body (42).

In the invention of claim 2, the clutch case (28) is fitted on the outer periphery of the cylindrical side surface of the cylindrical elastic body (44), and the screw (51)
Thus, the cylindrical elastic body (44) and the cylindrical rigid body (42) are fixed to the clutch case side fitting insertion portion (48).

〔Example〕

 The present invention will be described below with reference to the embodiments shown in the drawings.

FIG. 3 is a perspective view of the power brush cutter 10. The power unit 12 includes an engine, and has a clutch device at one end of a linear outer tube 14.
Mounted via 16. The gear device 18 is attached to the other end of the outer pipe 14, the cutting blade 20 is attached to the rotating shaft (not shown) of the gear device 18 below the gear device 18, and the cutting device 20 is connected to the inside of the outer pipe 14 from the clutch device 16. It is rotated by the rotational power transmitted through the transmission shaft 34 (FIGS. 1 and 2) and the gear device 18. The safety cover 22 is attached to the outer pipe 14 so as to cover the cutting blade 20 on the side of the operator who operates the power brush cutter 10, and prevents pebbles and the like from scattering toward the operator. The two grips 24 are fitted in the end portion of the outer tube 14 on the power unit 12 side with a space and are gripped by an operator.

FIG. 1 is a vertical sectional view of a connecting portion between the outer pipe 14 and the clutch device 16. The clutch device 16 has a clutch body 26 and a clutch case 28 that covers the outside of the clutch body 26. The clutch drum 30 of the clutch body 26 is powered by engagement with an inner peripheral side clutch shoe (not shown). Rotational power from the portion 12 is transmitted, and the boss 32 is integrally and rotatably fixed to the center of the clutch drum 30 so as to project from the clutch drum 30 toward the outer pipe 14. The transmission shaft 34 extends in the outer pipe 14 along its center line and is fitted into the boss 32 at one end so as to rotate integrally with the boss 32 by the spline. The ball bearing 36 is fitted between the inner circumference of the clutch case 28 and the outer circumference of the boss 32 to rotatably support the boss 32 on the clutch case 28. The retaining ring 38 is fitted on the inner circumference of the clutch case 28 to prevent the ball bearing 36 from coming off.

The connecting member 40 includes a tubular rigid body 42 and a tubular elastic body 44, and the tubular rigid body 42 has a large diameter portion 46 and a small diameter portion 48 which are fitted and inserted into the outer pipe 14 and the clutch case 28, respectively. . The tubular elastic body 44 is fitted between the inner periphery of the clutch case 28 and the outer periphery of the small diameter portion 48, and the outer diameter of the tubular elastic body 44 is equal to the outer diameter of the outer tube 14. 2 is a view taken along the line II-II in FIG.
The knurled groove 50 is formed on the outer periphery of the large diameter portion 46,
Are press-fitted on the inner peripheral side of the outer pipe 14.

In FIG. 1, the retaining screw 51 is inserted through the washer 52 and then through the through holes of the clutch case 28 and the tubular elastic body 44, and is screwed into the screw hole of the small diameter portion 48 to form the tubular elastic body. 44
Also, the small diameter portion 48 is prevented from coming off from the clutch case 28. The tightening screw 54 is inserted into the confronting part of the clutch case 28, and the confronting parts are mutually tightened to form the clutch case.
The inner circumference of 28 is crimped to the outer circumference of the cylindrical elastic body 44.

The operation of the embodiment will be described.

In order to connect and fix the tubular rigid body 42 to the outer tube 14, the tubular rigid body 42
The large diameter portion 46 of 42 is pressed into the outer tube 14. The large diameter portion 46 is inserted into the outer pipe 14 while being compressed and deformed so as to fill the knurled groove 50. Press-fitting is carried out by a machine without human intervention.

The vibration of the power unit 12 is transmitted to the outer peripheral side of the cylindrical elastic body 44 via the clutch case 28 of the clutch device 16, and the cylindrical elastic body 44
Receives the vibration, elastically deforms, absorbs the vibration, and suppresses the transmission of the vibration to the small diameter portion 48 of the tubular rigid body 42.

In the power brush cutter without the vibration isolator, the end of the outer pipe is fitted to the inner circumference of the clutch case, and the diameter of the end of the outer pipe and the inner circumference of the clutch case are set to be the same. Then, since the outer diameter of the tubular elastic body 44 is set equal to the outer diameter of the outer tube 14, the connecting member 40 of the embodiment is applied as it is to the outer tube and the clutch case of the power brush cutter without the vibration isolator. It is possible.

In the embodiment, in the connecting member 40, the large diameter portion 46 as the outer tube side fitting insertion portion is the small diameter portion 48 as the clutch case side fitting insertion portion.
Although it has a larger diameter, the present invention only requires that the outer tube side fitting insertion portion has a knurled groove formed on the outer peripheral surface and is press-fitted into the inner circumference of the outer tube. The size relationship between the diameter of the clutch case side fitting portion and the diameter of the clutch case side fitting portion is arbitrary.

[Effect of device]

According to the first aspect of the present invention, the tubular rigid body of the connecting member is fixed to the outer pipe by press-fitting the outer pipe side fitting insertion portion having the knurled groove on the outer peripheral surface, not by the screw. is doing.

(A) High accuracy is required to form the insertion hole and the screw hole of the fixing screw to the outer pipe on the outer pipe and the outer pipe side fitting insertion portion, and it is necessary for the insertion hole and the screw hole for a plurality of screws. Since it is possible to omit the processing, the manufacturing efficiency and simplification, and the manufacturing cost can be reduced.

(B) Since there is no insertion hole or screw hole for the fixing screw to the outer tube, stress is not concentrated on those holes, and the durability of the outer tube and the cylindrical rigid body is improved.

(C) Since there is no rattling between the outer tube and the outer tube side fitting insertion portion of the cylindrical rigid body, it is possible to prevent wear due to relative displacement between the two and suppress an increase in rattling.

(D) A knurled groove is formed in the outer pipe side fitting insertion portion of the cylindrical rigid body as the press-fitting portion, and when press-fitting, the outer pipe side fitting insertion portion is compressed and deformed so as to expand toward the knurling groove. It is possible to smoothly press fit the tube-side fitting portion and increase the strength of the outer tube-side fitting portion due to work hardening.

In the invention of claim 2, since the outer peripheral surface of the cylindrical elastic body is a cylindrical side surface over the entire axial direction without having a collar portion, the shape of the cylindrical elastic body is simple and the manufacturing is simplified. It Further, even if the clutch case is not fitted to the end portion of the tubular elastic body on the outer pipe side, the tubular elastic body fulfills the function of absorbing vibrations, so that it is possible to reduce the accuracy in size and positioning.

[Brief description of drawings]

1 is a longitudinal sectional view of a connecting portion between an outer tube and a clutch device, and FIG. 2 is a II-II of FIG.
The arrow view and FIG. 3 are perspective views of the power brush cutter. 10 …… Power brush cutter, 12 …… Power unit, 14 …… Outer tube, 20 ……
Cutting blade, 26 …… Clutch body, 28 …… Clutch case, 34
...... Transmission shaft, 40 ...... Connection member, 42 ...... Cylindrical rigid body, 44 ......
Cylindrical elastic body, 46 …… Large diameter part (outer tube side fitting insertion part), 48 …… Small diameter part (clutch case side fitting insertion part), 50 …… Knurled groove, 51 …… Tightening screw (screw).

Claims (2)

[Scope of utility model registration request] 1. Rotational power of a power section (12) is transmitted to a cutting blade (20) via a clutch body (26) and a transmission shaft (34), and the clutch body (26) and the transmission shaft (34). Are covered with the clutch case (28) and the outer pipe (14), respectively, and the connecting member (40) is fitted and inserted into the outer pipe (14) and the clutch case (28) on both sides, respectively. The cylindrical rigid body (42) fixed to the outer pipe (14) at the insertion portion (46), the outer circumference of the clutch case side fitting insertion portion (48) of the cylindrical rigid body (42), and the clutch case (28). Cylindrical elastic body (44) interposed between and fixed to the inner circumference of the
In the power brush cutter (10) including, the outer tube side fitting insertion part (46) of the tubular rigid body (42) has a knurled groove (50) on the outer peripheral surface thereof, and the outer tube (14) It is fixed to the outer pipe (14) by press fitting into the inner periphery, and the outer pipe (14) and the clutch case (28) are axially spaced so as not to contact each other. Anti-vibration device for power brush cutters. 2. An outer peripheral surface of the cylindrical elastic body (44) is a cylindrical side surface over the entire axial direction, and a screw (51) penetrates the cylindrical elastic body (44) in the radial direction, and the clutch case ( 2
8. The vibration damping device for a power brush cutter according to claim 1, wherein the cylindrical rigid body (42) and the clutch case side fitting insertion portion (48) of the tubular rigid body (42) are fixed.