U.S. patent application number 13/319631 was filed with the patent office on 2012-05-24 for hand-held power tool, in particular electric hand-held power tool.
This patent application is currently assigned to Robert Bosch GmbH. Invention is credited to Manfred Lutz, Joerg Maute, Joachim Schadow.
Application Number | 20120125648 13/319631 |
Document ID | / |
Family ID | 42357389 |
Filed Date | 2012-05-24 |
United States Patent
Application |
20120125648 |
Kind Code |
A1 |
Schadow; Joachim ; et
al. |
May 24, 2012 |
Hand-Held Power Tool, in Particular Electric Hand-Held Power
Tool
Abstract
A hand-held power tool is provided with a housing comprising two
separate and interconnected housing parts, one of which is designed
as a handle part for holding and guiding the hand-held power tool.
At least one housing part is associated with a vibration reduction
element designed as a spring element. The vibration reduction
element is arranged in an intermediate space between the handle
part and the other housing part.
Inventors: |
Schadow; Joachim;
(Stuttgart, DE) ; Maute; Joerg; (Sindelfingen,
DE) ; Lutz; Manfred; (Filderstadt, DE) |
Assignee: |
Robert Bosch GmbH
Stuttgart
DE
|
Family ID: |
42357389 |
Appl. No.: |
13/319631 |
Filed: |
April 12, 2010 |
PCT Filed: |
April 12, 2010 |
PCT NO: |
PCT/EP2010/054740 |
371 Date: |
February 7, 2012 |
Current U.S.
Class: |
173/46 |
Current CPC
Class: |
B25F 5/02 20130101; B25F
5/006 20130101 |
Class at
Publication: |
173/46 |
International
Class: |
E02F 3/96 20060101
E02F003/96 |
Foreign Application Data
Date |
Code |
Application Number |
May 11, 2009 |
DE |
102009002975.3 |
Claims
1. A hand-held power tool, comprising a housing which has at least
two separate housing parts configured to be connected to one
another, wherein one housing part is designed as a handle part
configured to hold and guide the hand-held power tool and wherein
there is arranged a vibration reduction element which interacts
with at least one housing part wherein the vibration reduction
element is configured as a separate spring element which is
arranged in a space between the handle part and a further housing
part.
2. The hand-held power tool as claimed in claim 1, wherein the
spring element is configured as a leaf spring.
3. The hand-held power tool as claimed in claim 2, wherein the leaf
spring forms a spring ring which is put around a housing part.
4. The hand-held power tool as claimed in claim 1, wherein the
spring element is configured as a helical spring.
5. The hand-held power tool as claimed in claim 1, wherein the
spring element is active in the direction of the housing
longitudinal axis.
6. The hand-held power tool as claimed in claim 1, wherein the
spring element is active in the circumferential direction.
7. The hand-held power tool as claimed in claim 1, wherein the
spring element is active in the radial direction.
8. The hand-held power tool as claimed in claim 1, wherein the
housing part interacting with the handle part (4) forms a motor
housing for accommodating a drive motor (3).
9. The hand-held power tool as claimed in claim 1, wherein the
handle part is of pot-shaped design and encloses the further
housing part.
10. The hand-held power tool as claimed in claim 9, wherein the
spring element is arranged in the region of the pot base or acts on
the pot base.
11. The hand-held power tool as claimed in claim 1, wherein the
spring element is arranged in an annular space which lies between
the inner side of the handle part and the outer side of the further
housing part enclosed by the handle part.
12. The hand-held power tool as claimed in claim 11, further
comprising a damping element is arranged between the handle part
and the further housing part.
13. The hand-held power tool as claimed in claim 12, wherein the
damping element is arranged between the inner side of the handle
part and the outer side of the further housing part.
14. The hand-held power tool as claimed in claim 12, wherein the
damping element forms a sliding element which is connected to one
of the housing parts and permits a relative movement of the other
housing part.
15. (canceled)
Description
[0001] The invention relates to a hand-held power tool, in
particular an electric hand-held power tool, according to the
preamble of claim 1.
PRIOR ART
[0002] Described in DE 10 2005 016 453 A1 is an electric hand-held
power tool which is embodied as an angle grinder and which has an
electric drive motor in a motor housing. For holding and guiding
the hand-held power tool, a pot-shaped handle part is
flange-mounted on the rear end face of the motor housing, wherein a
damping ring is arranged between motor housing and handle part in
order to dampen vibrations which emanate from the drive motor or
occur during the machining of a workpiece.
DISCLOSURE OF THE INVENTION
[0003] The object of the invention is to achieve an effective
reduction of vibrations in the handle part of a hand-held power
tool with simple design measures.
[0004] This object is achieved according to the invention by the
features of claim 1. The dependent claims specify expedient
developments.
[0005] The hand-held power tool according to the invention is
preferably an electric hand-held power tool, the drive unit of
which is designed as an electric drive motor which is arranged in a
motor housing. Adjoining the motor housing is a handle part, via
which the hand-held power tool is held and guided. A vibration
reduction element which has the task of reducing vibrations in the
handle part is located between the handle part and a further
housing part--as a rule the motor housing.
[0006] According to the invention, the vibration reduction element
is designed as a spring element which is arranged in a space
between the handle part on the one side and the further housing
part on the other side. To provide a spring element embodied as a
separate component as vibration reduction element has the advantage
that, firstly, the handle part is supported on the further housing
part and, secondly, amplitudes and frequencies of the vibrations
which emanate from the further housing part are shifted from
critical to noncritical values, such that the objective and
subjective vibration load in the handle part is reduced.
[0007] In principle, it is sufficient to provide only one or more
spring elements between the handle part and the further housing
part. However, it is also possible to additionally use damping
elements as vibration reduction elements.
[0008] Various spring types can be used as the spring element, for
example leaf springs, helical springs, disk springs, corrugated
springs, diaphragm springs or the like. On account of its
embodiment as a separate component in the space between the handle
part and the further housing part, the spring element is
expediently connected, for example screwed, to at least one of the
housing parts involved. However, it is also possible to allow the
spring element to bear against one housing part or against both
housing parts without a further fastening measure, where in this
case stops, recesses or other positive-locking devices are
expediently provided in order to fix the spring element to one
housing part or to both housing parts in a positive-locking manner
in the axial direction, in the radial direction and/or in the
circumferential direction.
[0009] The force is transmitted in one or more axial directions,
depending on where the spring element is fitted and on the type of
spring element. Transmission of force between the handle part and
the further housing part in the axial direction, that is to say in
the direction of the longitudinal axis of the hand-held power tool,
is possible in principle. In addition, support of the handle part
in the radial direction and in the circumferential direction is
also possible.
[0010] According to an advantageous embodiment, the handle part is
of hollow-cylindrical or pot-shaped design and is pushed onto the
further housing part, wherein an annular space is expediently
formed between the lateral surface of the further housing part and
the inner side of the handle part in order to avoid direct contact
between the walls of the handle part and of the further housing
part. There can also be a space in the region of the pot base or of
the end face of the further housing part in order to also avoid at
this location direct contact and a direct vibration transmission
associated therewith.
[0011] In a preferred embodiment, a first spring element, via which
mainly forces in the axial direction are transmitted, is arranged
in the region of the rear end face of the further housing part. At
least one further spring element is located in the annular space
between the lateral surface of the further housing part and the
inner side of the handle part, support in the radial direction and
if need be also in the circumferential direction being achieved via
this further spring element. A leaf spring element, for example, is
used in the region of the rear axial end face of the further
housing part and the pot base; either a helical spring active in
the radial direction or a corrugated spring element which extends
either over the entire circumference or over a partial angular
range in the circumferential direction can be used in the space
between the outer lateral surface of the housing part and the inner
side of the enclosing handle part. A spring element which is
preferably active in the axial direction can also be arranged on
the free end face of the handle part, said spring element being
supported on a step of the further housing part and extending
likewise either over the entire circumference or only over a
limited angular segment in the circumferential direction.
[0012] According to a further advantageous embodiment, a damping
element is arranged between the handle part and the housing part in
addition to the at least one spring element, which damping element
performs in particular the function of a sliding element and
permits a relative movement between the handle part and the further
housing part. The sliding element performs a supporting function in
the radial direction, the vibrations which emanate from the further
housing part being reduced on account of the damping properties.
The relative movement between the handle part and the further
housing part preferably takes place in the axial direction and/or
in the circumferential direction, if need be also in the radial
direction.
[0013] Further advantages and expedient embodiments can be seen
from the further claims, from the description of the figures and
from the drawings, in which:
[0014] FIG. 1 shows a hand-held power tool comprising a multi-piece
housing consisting of a motor housing for accommodating a drive
motor and a handle part which is of pot-shaped design and is pushed
onto the motor housing, wherein a vibration reduction element
embodied as a spring element is arranged in an annular space
between the lateral surface of the motor housing and the inner side
of the handle part, and comprising an additional damping element
which is arranged adjacent to the free axial end face of the handle
part,
[0015] FIG. 2 shows a further exemplary embodiment, comprising a
leaf spring between the base of the pot-shaped handle part and the
axial rear end face of the motor housing, and comprising a second
spring element in the annular space, said second spring element
extending in the circumferential direction,
[0016] FIG. 3 shows the spring element from FIG. 2 arranged in the
annular space, in a sectional illustration,
[0017] FIG. 4 shows a further exemplary embodiment comprising a
leaf spring element between the base of the handle part and the
rear axial end face of the motor housing and comprising a sliding
element in the annular space between motor housing and handle
part,
[0018] FIG. 5 shows a further exemplary embodiment comprising a
spring element between the free axial end face of the handle part
and comprising a step on the motor housing,
[0019] FIG. 6 shows a further exemplary embodiment comprising a
spring element designed as a corrugated spring in the annular space
between motor housing and handle part.
[0020] In the figures, the same components are provided with the
same reference numerals.
[0021] The electric hand-held power tool 1 shown in FIG. 1 has a
two-piece housing 5, consisting of a motor housing 2 with an
electric drive motor 3 arranged therein and a handle part 4 which
is of pot-shaped design and is pushed onto the motor housing 2. The
inside diameter of the handle part 4 is greater than the outside
diameter of the motor housing 2, as a result of which an annular
space is formed between the lateral surface of the motor housing 2
and the inner side of the handle part 4. The base 4a of the handle
part 4 is also at an axial distance from the rear axial end face 2a
of the motor housing 2. In this way, direct contact between the
motor housing 2 and the handle part 4 is to be avoided in order to
ensure that vibrations can spread from the motor housing 2 to the
handle part 4 only in a reduced manner.
[0022] The handle part 4 is supported on the motor housing 2 via a
spring element 6 which is arranged in the annular space between
motor housing 2 and handle part 4. In the exemplary embodiment
according to FIG. 1, the spring element 6 is designed as a helical
spring or if need be also as a corrugated spring and extends in the
radial direction, with respect to the longitudinal axis 8 of the
hand-held power tool 1. The spring element 6 supports the handle
part 4 on the motor housing 2 in the radial direction. If need be,
the spring element 6 also additionally acts in the circumferential
direction and therefore holds the handle part 4 in a desired
angular position with respect to the motor housing 2.
[0023] As viewed in the axial direction, the spring element 6 is
located close to the free end face of the pot-shaped handle part 4.
For securing and positioning in the axial direction, recesses into
which the spring element 6 is inserted are incorporated in the
lateral surface of the motor housing 2 and on the inner side of the
handle part 4.
[0024] A plurality of such spring elements can be distributed over
the axial length and if need be also over the circumference in
order to accordingly support the handle part 4 on the motor housing
2 over the axial length thereof and over the circumference.
[0025] Directly adjacent to the free end face, the handle part 4 is
supported with the inner side thereof on a sliding element 7 which
is put onto the lateral surface of the motor housing 2 or is
fastened there. The sliding element 7 permits a movement of the
handle part 4 relative to the motor housing 2, specifically in both
the axial direction and the circumferential direction and if need
be also in the radial direction. The sliding element 7 also
performs the function of a damping element and accordingly consists
of a damping material in order to ensure that vibrations of the
motor housing are transmitted only in a reduced manner when the
handle part 4 is in position. The sliding element 7 is an optional
component, which if need be can also be dispensed with.
[0026] In the exemplary embodiment according to FIG. 2, too, a
spring element 6 is located in the annular space between the
lateral surface of the motor housing 2 and the inner side of the
handle part 4, but this spring element 6, as can also be seen from
the sectional illustration according to FIG. 3, is embodied as a
corrugated leaf spring. The spring element 6 extends in the
circumferential direction, suitable embodiments being both those
having a leaf spring which extends only over a limited angular
segment and those having an annular leaf spring in which the spring
element extends over the entire circumference. On account of the
corrugated structure of the leaf spring 6, a plurality of spring
peaks and spring valleys respectively bear in a distributed manner
over the circumference against the inner side of the handle part 4
and respectively against the lateral surface of the motor housing
2.
[0027] In a similar manner to the preceding exemplary embodiment, a
sliding element 7 is located adjacent to the free end face of the
handle part 4 on the lateral surface of the motor housing 2, said
sliding element 7 supporting the inner side of the handle part 4.
This sliding element 7 is also optionally present and can be
omitted if need be.
[0028] Located in the axial space between the base 4a of the handle
part 4 and the rear axial end face 2a of the motor housing 2 is a
further spring element 9 which is designed as a leaf spring and is
fixedly connected to the rear end face of the motor housing 2 via a
screw 10. The spring element 9 is also connected to the inner side
of the base 4a of the handle part 4 via a further screw 11. The
spring element 9 primarily acts axially in the direction of the
longitudinal axis 8, but also acts in the radial direction and
circumferential direction.
[0029] The spring element 6 in the annular space is inserted into
recesses in the lateral surface of the motor housing 2 and on the
inner side of the handle part 4 and is thereby fixed in the axial
direction. In principle, it is sufficient to arrange the spring
element 6 without a fixed connection to the motor housing or to the
handle part, even though it is possible to also provide a fixed
connection on one housing part or on both housing parts.
[0030] In the exemplary embodiment according to FIG. 4, too, a
spring element 9 designed as a leaf spring is located in the axial
intermediate region between the inner side of the base 4a of the
handle part 4 and the rear axial end face of the motor housing 2.
The spring element 9 is axially connected to the motor housing 2
via the screw 10. In its radially outer region, the spring element
9 has a bent-over section, via which the spring element is
connected to the radial inner side of the handle part 4 via a
further screw 11. The connection is therefore effected in the
region of the annular space between the motor housing 2 and the
inner side of the handle part 4. The connection can also be carried
out via other connecting measures, for example via a snap
connection, by adhesive bonding, ultrasonic welding, etc.
[0031] The sliding element 7, which is arranged adjacent to the
free end face of the handle part 4 on the lateral surface of the
motor housing 2, can be dimensioned in such a way that, in a
desired position, the inner side of the handle part 4 is at a
distance from the sliding element 7, such that the sliding element
7 comes into contact with the inner side of the handle part 4 only
during a radial deflection from the desired position.
[0032] In the exemplary embodiment according to FIG. 5, an
expediently circumferential spring element 6 extending in the axial
direction is arranged between the free axial end face of the handle
part 4 and the motor housing 2, said spring element 6 being
embodied, for example, as a bellows or as a corrugated spring. The
spring element 6 is held at its axial end faces on fastening parts
12 and 13, of which the fastening part 12 projects into an
accommodating pocket 14 which is formed on the motor housing 2 or
is fastened to the latter, whereas the second fastening part 13 is
connected to the end face of the handle part 4.
[0033] In the exemplary embodiment according to FIG. 6, the spring
element is located in the annular space between the outer lateral
surface of the motor housing 2 and the inner side of the handle
part 4. The spring element 6 can be formed over the circumference
or if need be can also extend in the circumferential direction only
over a limited angular segment, where in the latter case a
plurality of spring elements can in principle be arranged in the
annular space in a distributed manner over the circumference. The
spring element 6 is designed as a corrugated spring and transmits
forces in both the axial direction and the circumferential
direction and in the radial direction. The spring element 6 is
connected via fastening parts 15 and 16 both to the inner side of
the handle part 4 and to the lateral surface of the motor housing
2. The fastening parts 15, 16 can each be part of a bayonet catch
in order to enable the spring element 6 to be changed in a simple
manner.
* * * * *