JP2808863B2 - Vibration drill - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vibration drill that rotates a tip tool and vibrates in an axial direction.

[Conventional technology]

Conventional vibration drills generate the vibration,
The one generally configured as shown in FIG. 7 is used. That is, an attachment means 7 for attaching a tip tool is provided at one end, and the other end is movable in the axial direction. A spindle 1 connected to a driving unit 6 comprising a motor, a speed reduction mechanism, etc., a rotating cam 15 having a large number of teeth formed in a ring shape with irregularities in the axial direction, and teeth corresponding to the rotating cam 15. And a slide cam 16 that is spring-biased toward the rotating cam 15 and is loosely fitted to the spindle 1.

In this type, when an axial load is applied to the tip tool, the rotating cam 15 fixed to the spindle 1 moves to a position where it engages with the slide cam 16, and the rotation of the rotary cam 15 causes the slide cam 16 urged to be elastically resilient. Move axially against force. When the rotation cam 15 finishes rotating for one tooth, the slide cam 16 momentarily meshes with the next tooth. At this time, an impact force corresponding to the magnitude of the elastic force is applied to the rotating cam 15. In this way, each time the rotary cam 15 makes one rotation, an impact is given to the tip tool a number of times corresponding to the number of meshing teeth to vibrate. Therefore, the rotation speed of the spindle 1 and the vibration frequency per time are in a proportional relationship.

In the case of driving this vibration drill using a battery as a power source, changing the frequency according to the material to be processed is effective in efficiently using the battery capacity. That is, the frequency is increased for drilling a hard target, and the frequency is decreased for drilling a soft target. As a result, when the object is soft, the number of rotations is reduced, so that the load is reduced and power can be saved.

However, when the frequency is changed using the already incorporated rotation speed switching means, if the "high speed" rotation is selected, the rotation cam 15 and the slide cam 16 are disengaged from each other due to too high speed, and a desired impact force cannot be obtained. If the drilling speed was reduced or "slow" rotation was selected, the frequency per hour would be too low to increase the drilling speed.

To solve this problem, for example, Japanese Patent Application Laid-Open No. 62-9908
As proposed in 6, the teeth of the rotating cam and the slide cam are alternately arranged with high and low teeth, and the position of the slide cam is regulated to engage the rotating cam and the slide cam. A regulating means for controlling the amount is provided. This regulating means operates in conjunction with the means for switching the number of revolutions of the spindle. That is, the rotation speed is "low speed"
When the rotational speed is switched to "high speed", the members with high tooth height are regulated to mesh with each other at the tooth tip portion.

When the rotation speed is "low speed", the high and low tooth heights mesh with each other, so the frequency per rotation of the spindle increases, and when the rotation speed is "high speed", the tooth height increases. Since only high ones mesh with each other, the frequency of vibration per rotation of the spindle is reduced.

[Problems to be solved by the invention]

In the vibration drill as described above, if the frequency per rotation is increased, the load on the motor increases due to the engagement of the high tooth height. Then, it must be driven at a low speed in order to obtain a driving force capable of driving this. For this reason,
The frequency per hour for obtaining the desired drilling speed cannot be obtained. Further, even if "high speed" rotation is selected because the frequency per rotation is small, the frequency per time for obtaining a desired perforation speed cannot be obtained. Further, the amount of engagement between the rotary cam and the slide cam changes, so that the vibration amplitude and cam shape of the slide cam change, thereby changing the magnitude of the impact force according to the magnitude of the elastic force. For this reason, in order to obtain a desired perforation speed, there are many fluctuation factors for this and it is difficult to design.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to easily obtain a frequency per hour for obtaining a desired drilling speed and reduce a variation factor for the drilling speed. To provide a vibration drill that can be easily designed.

[Means for solving the problem]

In order to achieve the above object, a vibration drill of the present invention is rotatably supported in an axially movable state, provided with an attaching means for attaching a tip tool at one end, and a shaft at the other end. A spindle connected to the drive unit in a state capable of moving in the center direction, and an inner cam portion and an outer cam having a large number of teeth which are uneven in the axial direction and having different numbers of teeth concentrically A rotary cam having a portion and fixed to the spindle, an inner slide cam having teeth corresponding to the inner cam portion, being spring-biased toward the inner cam portion and being loosely fitted to the spindle, An outer slide cam having teeth corresponding to the outer cam portion and being spring-biased toward the outer cam portion to be loosely fitted to the inner slide cam, and either an inner or outer slide cam. Switching means for selectively engaging the inner cam portion or the outer cam portion; and To have.

[Action]

According to this configuration, the tooth length is made the same, the engagement amount between the rotary cam and the slide cam is made constant, the impact force according to the magnitude of the elastic force is made constant, and independent cams having different numbers of teeth are selectively used. The frequency can be changed by engaging with.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 6.

Reference numeral 1 denotes a spindle, which is formed with a six-stage shaft portion, has attaching means 7 for attaching a tip tool at one end, and a driving portion 6 at the other end.
Are connected to the output side by engagement of a spline or the like. The bearings 8 and 8 are supported by the bearings 8 and 8 so as to be movable in the axial direction. The speed reducer of the drive unit 6 is formed by superimposing a three-stage planetary mechanism, a pinion 6b fixed to an output shaft of a motor 6a is connected to an input side, and a spline shaft part of the spindle 1 is connected to an output side carrier 6c. 1a etc. are connected. The attachment means 7 is composed of a drill chuck or the like, and is screwed to a screw portion 1b provided at the tip of the spindle 1. This axial movement is performed by a rotary cam 2 (to be described later) fixed to a fourth stage (hereinafter, counted from the shaft provided with the threaded portion 1b).
Alternatively, it can be made to a position where the shaft end face of the second stage is regulated by the bearing 8.

Reference numeral 2 denotes a rotary cam, which is made of a sintered alloy and has a large number of teeth having a saw-tooth cross-section that becomes uneven in the axial direction.
An inner cam portion 2a and an outer cam portion 2b, which are provided concentrically and have one to two teeth, are integrally formed. Then, it is fixed to the fourth shaft portion of the spindle 1.

Reference numeral 3 denotes an inner slide cam, which is made of a sintered alloy, and has a tooth 3a corresponding to the inner cam portion 2a on one end surface, and a hole 3b for loosely fitting the shaft portion of the fourth stage of the spindle 1 at the shaft center. A sliding portion 3c loosely fitted on an outer slide cam 4 described later on the outer periphery, and a key portion 3d engaged with a key groove 4b of the outer slide cam 4 described later on the sliding portion 3c, The teeth 3a are spring-biased toward the inner cam portion 2a, and are suspended by the inner spring 13.

Reference numeral 4 denotes an outer slide cam, which is made of a sintered alloy. One end face of the outer slide cam 2b has teeth 4a corresponding to the outer cam portion 2b, and an axial center portion of the inner slide cam 3 is loosely fitted to the key portion 3d. It has a hole 4c provided with a key groove 4b, and a protruding piece 4d engaging with a groove 9a of the gear case 9 on three sides on the outer periphery, and the teeth 4a are spring-biased toward the outer cam portion 2b. You. The outer slide cam 4 is regulated in the rotation direction of the spindle 1 by engagement with a groove 9 a provided in the axial direction of the gear case 9.

Reference numeral 5 denotes a switching means, which is engaged with the housing 10 and is supported so as to be rotatable at a predetermined angle around the axis of the spindle 1; And a switching plate 12 supported in a movable state. An annular cam portion 11a is provided on an inner surface of the switching handle 11 facing the distal end surface of the gear case 9. One end of the switching plate 12 is constantly pressed against the cam portion 11a by the outer slide cam 4 biased by a spring.

 Next, the operation of this device will be described.

FIG. 1 shows a state in which the switching handle 11 is in the initial position,
The switching plate 12 projects out of the gear case 9 and the cam portion 11a
Is in contact with As a result, the outer slide cam 4 protrudes from the spring-suspended inner slide cam 3c (as shown in FIG. 2) at a position in contact with the end of the switching plate 12, and an external force acts on the spindle 1 in the direction of the arrow. And the outer cam portion 2d. At this time, there is no engagement between the inner slide cam 3 and the inner cam portion 2a. Only the outer slide cam 4 vibrates in the axial direction as the rotary cam 2 rotates, and applies an impact force to the spindle 1 via the rotary cam 2 according to the elastic force of the outer spring 14. If the switching handle 11 is selected in this position, vibration having a large frequency can be obtained.

FIG. 3 shows that the switching plate 12 is driven by the cam portion 11a and moves into the gear case 9 in a state where the switching handle 11 is rotated by a predetermined angle from the initial position. As a result, the outer slide cam 4 is retracted from the spring-suspended inner slide cam 3 toward the drive unit 6 (the inner slide cam 3 projects from the outer slide cam 4 as shown in FIG. 4). ,
When an external force acts on the spindle 1 in the direction of the arrow, the spindle 1 meshes with the inner cam portion 2a. At this time, the outer slide cam 4 and the outer cam portion
There is no engagement of 2b. Only the inner slide cam 3 vibrates in the axial direction as the rotary cam 2 rotates, and applies an impact force to the spindle 1 via the rotary cam 2 according to the elastic force of the inner spring 13. If the switching handle 11 is selected in this position, vibration with a low frequency can be obtained.

In addition, when used in combination with the rotation speed switching means, if the frequency is selected for each of "high speed" and "low speed" rotations, four types of usage can be used, and the degree of freedom according to the processing object can be increased.

〔effect〕

In the vibration drill of the present invention, the impact force according to the magnitude of the elastic force is kept constant, and only the vibration frequency is changed by selectively engaging independent cams having different numbers of teeth. Thus, the frequency per time for obtaining the perforation is easily obtained, and a variation factor with respect to the perforation speed is reduced so that the design can be easily performed.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, and is a cross-sectional view of a selected state having a large frequency, FIG. 2 is a partial perspective view of FIG. 1 during a transition, and FIG. FIG. 4 is also a partial perspective view of FIG. 3 during a transient state, FIG. 5 is a sectional view taken along the line AA of FIG. 1, and FIG. Is a partial sectional view of a cam portion of the switching handle, and FIG. 7 is a partial sectional view of a conventional example. 1 ... spindle, 2 ... rotating cam, 2a ... inner cam section, 2b ... outer cam section, 3 ... inner slide cam, 4 ... outer slide cam, 5 ... switching means.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B25D 16/00 B23B 45/16

Claims (1)

(57) [Claims] 1. A driving unit which is supported so as to be movable in an axial direction, and has an attaching means for attaching a tip tool at one end and a movable end in an axial direction at the other end. Having an inner cam portion and an outer cam portion concentrically having different numbers of teeth, the rotation being fixed to the spindle. A cam having teeth corresponding to the inner cam portion, an inner slide cam spring-loaded toward the inner cam portion to be loosely fitted to the spindle, and a tooth corresponding to the outer cam portion. , The outer slide cam that is spring-biased toward the outer cam section and is loosely fitted to the inner slide cam, and selects either the inner or outer slide cam as the inner cam section or the outer cam section. A vibrating drill, comprising: switching means for engaging the same.