Hand-power tool with an oscillation-damping device

Abstract

A hand-power tool includes at least one oscillation-damping device that has at least one damping spring, a damping mass, and a mechanism housing. The oscillation-damping device has at least two retaining parts that at least partly enclose the damping mass.

Claims

1. A portable power tool, comprising: at least one vibration absorbing device which includes: an absorption mass; at least one absorption spring defining a spring direction along which the at least one absorption spring transmits a spring force to the absorption mass; at least two holding parts at least partially enclosing the absorption mass such that the at least two holding parts surround at least one point of the absorption mass on a plane oriented perpendicularly to the spring direction; and at least one spring receptacle connected in a form-fitting and mechanically fixed manner to the absorption mass; and a mechanism housing.

2. The portable power tool as claimed in claim 1, wherein the at least one absorption spring is configured to exert a fastening force on the mechanism housing, the at least one absorption spring and the mechanism housing being configured such that the fastening force counteracts and prevents a movement of at least a portion of the vibration absorbing device in at least one operating state.

3. The portable power tool as claimed in claim 1, wherein the holding parts are formed as identical parts having identical external dimensions.

4. The portable power tool as claimed in claim 1, wherein the holding parts are configured to guide the absorption spring such that the holding parts exert a bearing force on the absorption spring in a direction perpendicular to the spring direction.

5. The portable power tool as claimed in claim 1, wherein the mechanism housing includes a housing cover which has a fastening mechanism configured to fasten at least a portion of the vibration absorbing device such that the portion of the vibration absorbing device cannot move in relation to the housing cover.

6. The portable power tool as claimed in claim 1, wherein the at least one spring receptacle exerts an acceleration force on the absorption mass in a first operating state and exerts an opposition force on the holding part in a second operating state.

7. The portable power tool as claimed in claim 6, further comprising: at least one support element configured to exert a support force on the at least one spring receptacle in a direction opposite the acceleration force exerted by the absorption spring.

8. The portable power tool as claimed in claim 1, wherein the absorption spring is arranged entirely in an axial region of the absorption mass that is bounded by two planes oriented perpendicularly to the spring direction and which intersect the absorption mass.

9. The portable power tool as claimed in claim 1, wherein the at least one spring receptacle includes a contact surface abutting the absorption mass, and the at least one spring receptacle is configured such that the form-fitting connection transmits a first force between the at least one spring receptacle and the absorption mass over the contact surface in a force direction, and the contact surface extends perpendicular to the force direction.

10. A vibration absorbing system for a portable power tool, comprising: at least one vibration absorbing device which includes: an absorption mass; at least one absorption spring defining a spring direction along which the at least one absorption spring transmits a spring force to the absorption mass; at least two holding parts at least partially enclosing the absorption mass such that the at least two holding parts surround at least one point of the absorption mass on a plane oriented perpendicularly to the spring direction; and at least one spring receptacle connected in a form-fitting and mechanically fixed manner to the absorption mass; and a mechanism housing.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) Further advantages can be gathered from the following description of the drawing. The drawing illustrates two exemplary embodiments of the disclosure. The drawing, the description and the claims contain numerous features in combination. A person skilled in the art will expediently view the features individually and combine them to form practical further combinations.

(2) In the drawing:

(3) FIG. 1 shows a portable power tool according to the disclosure, having a vibration absorbing device which is fastened to a housing cover,

(4) FIG. 2 shows a section through the portable power tool from FIG. 1,

(5) FIG. 3 shows a housing cover and the vibration absorbing device of the portable power tool from FIG. 1,

(6) FIG. 4 shows a section (A-A) through the housing cover and the vibration absorbing device,

(7) FIG. 5 shows a plan view of a partial section through the vibration absorbing device of the portable power tool from FIG. 1,

(8) FIG. 6 shows a front view of a section (B-B) through the vibration absorbing device of the portable power tool from FIG. 1,

(9) FIG. 7 shows a side view of the vibration absorbing device of the portable power tool from FIG. 1,

(10) FIG. 8 shows a partial section through an alternative exemplary embodiment of the vibration absorbing device from FIG. 1 with a spring receptacle which is movable in relation to the absorption mass, and

(11) FIG. 9 shows a front view of a section (C-C) through the vibration absorbing device from FIG. 8.

DETAILED DESCRIPTION

(12) FIG. 1 shows a portable power tool 10a according to the disclosure having a vibration absorbing device 12a, a drive mechanism 18a and having a mechanism housing 20awhich has a metal housing cover 22a. The portable power tool 10a is formed as a rotary and demolition hammer. The mechanism housing 20a encloses a chamber 24a in which the drive mechanism 18a and the vibration absorbing device 12a are arranged. Furthermore, the portable power tool 10a has a main handle 44a, an application tool fastening 46a, a motor housing 48aand an auxiliary handle 50a. The main handle 44a is connected to the mechanism housing 20aand the motor housing 48a on a side of the mechanism housing 20a that is remote from the application tool fastening 46a. The auxiliary handle 50a is connected to the mechanism housing 20a on a side facing the application tool fastening 46a.

(13) FIG. 2 shows a section through the mechanism housing 20a, which has a housing shell 52a in addition to the housing cover 22a. Arranged in the chamber 24a are the vibration absorbing device 12a and the drive mechanism 18a. The drive mechanism 18a has a percussion mechanism 28a, a first and a second transmission element 54a, 56a for drilling operation and a switching mechanism 58a. The percussion mechanism 28a is formed as a hammer percussion mechanism. The first transmission element 54a is formed additionally as an eccentric element of the percussion mechanism 28a. Furthermore, the percussion mechanism 28a has a piston 59a, a hammer tube 60a and, not illustrated in more detail, a striker and an anvil. The second transmission element 56a drives the hammer tube 60a in rotation. The rotational movement of the hammer tube 60a can be switched off by the switching mechanism 58a in a manner that appears to be practical to a person skilled in the art.

(14) The housing cover 22a of the mechanism housing 20a is arranged on a side of the housing shell 52a that is opposite the motor housing 48a. It closes a fitting opening located there, and thus the chamber 24a. The portable power tool 10a has a seal (not illustrated in more detail), which is arranged between the housing cover 22a and the housing shell 52a. As a result, the vibration absorbing device 12a and the drive mechanism 18a are protected from contamination. The chamber 24a is formed as a grease chamber, that is to say that joint, permanent lubrication is ensured in the chamber 24a. The vibration absorbing device 12a and the drive mechanism 18a are arranged in the chamber 24a, which is closed by the housing cover 22a.

(15) As is shown in FIGS. 3 to 7, the housing cover 22a has three fastening means 26a. The fastening means 26a are formed as integrally formed webs. The fastening means 26a have fastening surfaces 62a oriented perpendicularly to a spring direction 30a. The fastening means 26a fasten the vibration absorbing device 12a in the spring direction after the fitting of the subassembly, that is to say after the vibration absorbing device 12a has been inserted into the cover, and during operation. To this end, during fitting, the vibration absorbing device 12a is compressed in the spring direction 30a and inserted into the housing cover 22a. As a result, absorption springs 14a of the vibration absorbing device 12a bring about a fastening force on the housing cover 22a by prestressing in the spring direction 30a after the fitting of the subassembly and during operation. The fastening force fastens the vibration absorbing device 12a to the housing cover 22a in a force-fitting manner perpendicularly to the spring direction 30a. Thus, the vibration absorbing device 12a and the housing cover 22a form a preassemblable subassembly, that is to say that the vibration absorbing device 12a and the housing cover 22a form together, and separately from the housing shell 52a, an inherently stable unit.

(16) Following fitting of the housing cover 22a on the housing shell 52a, the housing shell 52a brings about a fastening force on the vibration absorbing device 12a in a region which is not illustrated in more detail. The fastening force acts perpendicularly to the spring direction 30a. Alternatively or in addition, the vibration absorbing device 12a could be latched, screwed, adhesively bonded and/or connected to the housing cover 22a in some other way that appears to be practical to a person skilled in the art.

(17) The percussion mechanism 28a and the vibration absorbing device 12a are arranged partially on identical planes, which are oriented perpendicularly to a spring direction 30a, that is to say that the percussion mechanism 28a and the vibration absorbing device 12a are arranged partially adjacent to one another. A region of the vibration absorbing device 12a that faces the application tool fastening 46a is arranged between the housing cover 22a and the percussion mechanism 28a. This region is free of functional components apart from the vibration absorbing device 12a.

(18) The vibration absorbing device 12a is formed in a mirror-symmetrical manner in a rest state. It has four absorption springs 14a, an absorption mass 16a, two holding parts 32a, two spring receptacles 36a and two spring receptacle fastenings 64a. The two holding parts 32a are formed as identical parts, that is to say that they have an identical but mirror-inverted form with respect to one another. In addition, the holding parts 32a have a slight oversize with respect to the housing cover 22a. Outer sides 66a of the holding parts 32a, which face or are remote from the application tool fastening, fasten the vibration absorbing device 12a in the housing cover 22a. The absorption springs 14a, the absorption mass 16a, the two spring receptacles 36a and the two spring receptacle fastenings 64a are arranged between the holding parts 32a. The spring receptacles 36a and the spring receptacle fastenings 64a are produced at least partially from plastics material.

(19) The holding parts 32a have guide surfaces 68a, which guide the absorption mass 16a in the spring direction 30a during operation. For this purpose, the holding parts 32a enclose the absorption mass 16a on a plane which is formed perpendicularly to the spring direction 30a. In this exemplary embodiment, the holding parts 32a enclose the absorption mass 16a entirely.

(20) Alternatively, the holding parts 32a could enclose the absorption mass 16a by more than 180 degrees. The holding parts 32a guide the absorption mass 16a on surfaces which are arranged furthest away from the center of gravity 70a of the absorption mass 16a, as a result of which small guide forces and a low degree of friction can be achieved. Alternatively or in addition, a housing cover could also guide the absorption mass 16a and/or the absorption spring 14a. Furthermore, the holding parts 32a each have spring fastenings 72a, which fasten the absorption springs 14a. For this purpose, the absorption springs 14a are screwed onto the spring fastenings 72a.

(21) The four absorption springs 14a are each connected in a mechanically fixed manner on one side to the holding parts 32a and on one side to the spring receptacles 36a. The spring receptacles 36a have a cruciform cross section as seen perpendicularly to the spring direction 30a (FIG. 5). On a side facing the center of gravity 70a of the absorption mass 16a, the spring receptacles 36a extend into recesses 74a in the absorption mass 16a. In this case, the spring receptacles 36a are supported on the absorption mass 16a. During fitting, the spring receptacle fastenings 64a are pushed onto the absorption mass 16a and fix the spring receptacles 36a such that a form-fitting connection is established between the spring receptacles 36a and the absorption mass 16a. The spring forces of the absorption springs 14a fasten the spring receptacle fastening 64a.

(22) In addition, the vibration absorbing device could have damping elements (not illustrated in more detail), which damp a striking of the absorption mass 16a against an end stop. For example, the damping elements could be arranged between the spring receptacles 36a and the holding parts 32a inside the absorption springs 14a in a guide for the holding parts 32a or on the housing cover 22a.

(23) The absorption mass 16a has a uniform cross section in the spring direction 30a. The cross section is formed by means of an extrusion process. Absorption masses are cut down from a bar by a machine and in the same work step are provided with recesses for accommodating spring receptacles. Alternatively or in addition, an absorption mass could have a plurality of mass parts. Advantageously, at least one of the mass parts likewise has a uniform cross section. Particularly advantageously, at least one of the mass parts has a preferably largely standardized cross section in at least one direction.

(24) FIGS. 8 and 9 show a further exemplary embodiment of the disclosure. In order to differentiate the exemplary embodiments, the letter a in the reference signs of the exemplary embodiment in FIGS. 1 to 7 has been replaced by the letter b in the reference signs of the exemplary embodiment in FIGS. 8 and 9. The following descriptions are limited substantially to the differences between the exemplary embodiments, it being possible to refer to the description of the other exemplary embodiments, in particular in FIGS. 1 to 7, with regard to components, features and functions which remain the same.

(25) The exemplary embodiment in FIGS. 8 and 9 relates, as described in the exemplary embodiment of FIGS. 1 to 7, to a portable power tool 10b according to the disclosure having a vibration absorbing device 12b illustrated in FIGS. 8 and 9, a drive mechanism 18band a mechanism housing 20b having a housing cover 22b and a housing shell 52b. In an operationally ready state, the housing cover 22b closes a chamber 24b in which the drive mechanism 18b is arranged. The housing cover 22b has fastening means 26b, which fasten the vibration absorbing device 12b in the operationally ready state.

(26) The vibration absorbing device 12b has two absorption springs 14b, an absorption mass 16b, a first and a second holding part 32b, a first and a second spring receptacle 36b, 38b, and four support elements 40b, 42b. The holding parts 32b are pushed onto the absorption mass 16b. There, the holding parts 32b are secured by way of immobilizing elements 94b. The immobilizing elements 94b are formed as clamping sleeves, but could also be formed as other units that appear to be practical to a person skilled in the art. The holding parts 32b are mounted in a movable manner in the spring direction 30b on the absorption mass 16b, specifically between in each case two immobilizing elements 94b and a central shoulder 96b. The central shoulder 96b extends perpendicularly to the spring direction 30b.

(27) The first holding part 32b and the first spring receptacle 36b are arranged facing the application tool fastening 46b. In an operating state, the absorption mass 16b moves the second spring receptacle 38b in the direction of the application tool fastening 46b. In the process, the second spring receptacle 38b exerts an acceleration force on the absorption mass 16b. The acceleration force brakes the absorption mass 16b. The second spring receptacle 38b in the process transmits movement energy of the absorption mass 16b via the immobilizing elements 94b to the absorption springs 14b. The absorption springs 14b buffer store this energy. After the absorption springs 14b have stopped the absorption mass 16b in relation to the holding parts 32b, the absorption springs 14b return the energy to the absorption mass 16b and thus accelerate the absorption mass 16b. During this movement of the absorption mass 16b from a central position in the direction of the application tool fastening 46b, the first spring receptacle 36b supports an opposing force to the acceleration force on the first holding part 32b. Once the absorption mass 16b has crossed a central position, the same process occurs in a mirror-inverted manner in the opposite direction.

(28) The support elements 40b, 42b press the spring receptacles 36b, 38b against the absorption springs 14b in two different operating states. A force of the support elements 40b, 42b is in this case much smaller than the acceleration force of the absorption springs 14b. The support elements 40b, 42b are in this case oriented coaxially with the absorption springs 14b. The absorption springs 14b are arranged entirely in an axial region, that is to say laterally next to the absorption mass 16b.