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.

Description

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

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

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.

This object is achieved according to the invention by the features of claim 1. The dependent claims specify expedient developments.

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.

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.

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.

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.

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.

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.

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.

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.

Further advantages and expedient embodiments can be seen from the further claims, from the description of the figures and from the drawings, in which:

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,

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,

FIG. 3 shows the spring element from FIG. 2 arranged in the annular space, in a sectional illustration,

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,

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,

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.

In the figures, the same components are provided with the same reference numerals.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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)