阅读说明：本技术 用于电气动锤钻的复合齿轮 (Composite gear for electro-pneumatic hammer drill ) 是由 D·塞尔特曼 J·芬费尔 于 2020-06-17 设计创作，主要内容包括：本发明披露了一种用于电气动锤钻的复合齿轮,其中,该复合齿轮具有基体,该基体由第一材料构成,并且其中,该环齿沿着第一弧段由该复合齿轮的带齿本体构成,并且沿着剩下的第二弧段由基体自身构成,其中,该带齿本体由与该第一材料不同的第二材料构成。(A composite gear for an electropneumatic hammer drill is disclosed, wherein the composite gear has a base body composed of a first material, and wherein the ring gear is composed of a toothed body of the composite gear along a first arc and of the base body itself along a remaining second arc, wherein the toothed body is composed of a second material different from the first material.)

1. A composite gear (10) for an electropneumatic hammer drill (100), wherein the composite gear (10) comprises a basic body (1) consisting of a first material (M1) and a ring gear (3),

characterized in that the ring gear (3) is formed by the toothed body (5) of the composite gear (10) along a first circular arc (K1) and by the basic body (1) itself along a remaining second circular arc (K2), wherein the toothed body (5) is composed of a second material (M2) which is different from the first material (M1).

2. Compound gear (10) according to claim 1,

characterized in that the first circular arc (K1) has a central angle (ZW) of less than 90 degrees, preferably less than 45 degrees.

3. Compound gear (10) according to claim 1 or 2,

characterized in that the basic body (1) has a groove (7) into which the toothed body (5) is at least partially introduced.

4. Compound gear (10) according to one of the preceding claims,

characterized in that, in order to compensate for the unbalance caused by the toothed body (5), the compound gear (10) has a balancing weight (9).

5. Compound gear (10) according to one of the preceding claims,

characterized in that the first material (M1) is a plastic and/or the second material (M2) is a steel material.

6. Compound gear (10) according to one of the preceding claims,

characterized in that exactly one toothed body (5) is provided, which comprises a plurality of teeth (3') of the ring gear (3).

7. Compound gear (10) according to one of the preceding claims,

characterized in that the compound gear (10) comprises a hub (2) for defining the timing of the compound gear (10).

8. Compound gear (10) according to claim 6,

characterized in that the hub (2) is in the form of an insert and preferably has an internal toothing (4) with eight teeth.

9. An electro-pneumatic hammer drill (100) with a compound gear (10) according to one of the preceding claims, wherein the compound gear (10) has been mounted in a transmission unit (30) of the hammer drill (100) in such a way that only that part of the ring gear (3) formed by the toothed body (5) is directly subjected to the increased torque of the impact mechanism (20) of the hammer drill (100).

Technical Field

The invention relates to a composite gear for an electropneumatic hammer drill, wherein the composite gear comprises a basic body and a ring gear part, wherein the basic body is made of a first material.

Background

Compound gears of the type mentioned at the outset are known in principle from the prior art.

Disclosure of Invention

The object of the present invention is to provide a composite gear, in particular for use in a drive unit of an electropneumatic hammer drill, which has a high stability and at the same time a low weight.

The purpose is realized by that: the ring gear is formed by a toothed body of the composite gear along a first circular arc and by the matrix itself along a remaining second circular arc, wherein the toothed body is composed of a second material different from the first material.

The present invention combines the following findings: the gearwheels, in particular when they are used in the drive unit of an electropneumatic hammer drill in cooperation with the percussion mechanism, are directly subjected to a torque which depends on the crank angle. The torque increases periodically, and can vary up to an order of magnitude along a 360 degree circumference. Since the ring gear of the composite gear according to the invention is formed along the first circular arc by a toothed body, preferably consisting of steel, the ring gear weight gain, which is highly loadable but also heavy, can be limited to a minimum. Thus, the composite gear according to the present invention has high stability and low weight. Preferably, the ring gear is formed along the first circular arc only by the toothed body of the compound gear.

It has been found to be advantageous that the first circular arc has a central angle of less than 90 degrees, preferably less than 45 degrees.

In a particularly preferred embodiment, the base body has a groove into which the toothed body is at least partially introduced. In particular, the toothed body is held in the basic body (both in the circumferential direction and in the radial direction) in a form-fitting manner. The toothed body can be held in the basic body in the radial direction by a press fit, for example by being pressed in. Preferably, exactly one toothed body is provided, which comprises a plurality of teeth of the ring gear.

In a particularly preferred embodiment, the compound gear has a balancing weight in order to compensate for the weight imbalance caused by the toothed body. Preferably, the balancing weight is provided as a separate weight arranged on the opposite side of the toothed body on the compound gear. Alternatively or in addition, the balancing weight may be formed integrally with the base body, for example by material thickening.

It has been found advantageous that the first material is a plastic, such as a thermoplastic or thermoset. The second material is preferably a metal, in particular a hardened metal. Particularly preferably, the second material is a steel material. Preferably, the composite gear is lighter than 150 grams in weight.

In a further preferred configuration, the compound gear has a central hub which is preferably arranged to define the timing of the compound gear. The hub may be in the form of an insert and preferably has an internal tooth portion with eight teeth. The insert can be held in the base body in a form-fitting, press-fitting or material-bonding manner. The hub in the form of an insert is preferably composed of metal, in particular hardened metal, preferably steel.

According to the invention, an electropneumatic hammer drill is likewise provided, in which the compound hammer has a compound gear of the type described above, wherein the compound gear is mounted in the drive unit of the hammer drill in such a way that only that part of the ring gear which is formed by the toothed body is directly subjected to the torque which is added by the percussion mechanism of the hammer drill. By referring to the features described with reference to the compound gear, an electro-pneumatic hammer drill may be advantageously developed.

Drawings

Further advantages will become apparent from the following description of the drawings. Various exemplary embodiments of the invention are illustrated in the accompanying drawings. The figures, description and claims contain many combinations of features. It will also be convenient for those skilled in the art to consider these features separately and combine them to produce useful further combinations.

In the drawings, the same and similar components are denoted by the same reference numerals. In the drawings:

FIG. 1 illustrates a first preferred exemplary embodiment of a compound gear according to the present invention; and

fig. 2 shows an electro-pneumatic hammer drill with the compound gear of fig. 1.

Detailed Description

A preferred exemplary embodiment of a compound gear 10 according to the present invention is illustrated in fig. 1. The compound gear 10 may be used in a transmission unit 30 (see fig. 2) of an electro-pneumatic hammer drill 100.

The composite gear wheel 10 has a basic body 1, which is made of a first material M1, which in this case is, for example, a thermoplastic, and a ring gear part 3. The ring gear 3 is formed along the first circular arc K1 only by the toothed body 5 of the compound gear 10. Exactly one toothed body 5 is provided, which comprises a plurality of teeth 3' of the ring gear 3. The second toothed body 5 is formed of a second material M2, which is different from the first material M1. Here illustrated, the second material M2 is a steel material.

As can be seen from fig. 1A, the ring toothing 3 is formed by the basic body 1 itself along the remaining second circular arc K2. Both the first arc K1 and the second arc K2 are each associated with the rotational axis D of the compound gear 10 and together form a full circle.

In the exemplary embodiment illustrated in fig. 1A, first circular arc K1 has a central angle ZW of less than 45 degrees, in this case, for example, about 40 degrees. This central angle corresponds to a relatively high torque carrying sector (see fig. 2B).

The compound gear 10 in fig. 1A also has a hub 2 for defining the timing of the compound gear 10.

FIG. 1B shows the compound gear 10 of FIG. 1A in an exploded view. It is clear that the toothed body 5 is in the form of a separate part from the basic body 1. In order to retain the toothed body 5 in the base body 1, the base body 1 has a groove 7 into which the toothed body 5 has been at least partially introduced (fig. 1A shows the toothed body 5 introduced into the groove 7). As can be appreciated from fig. 1B, the toothed body 5 has a cut-out 6. This aspect is intended to reduce weight. On the other hand, the toothed body 5 can be fastened in the radial direction R by this cut-out 6 and the cut-out 6' formed in the basic body 1. This can be achieved, for example, by inserting a pin (the pin is not shown in the figures) or by co-casting the cut-outs 6, 6'.

As can be appreciated from fig. 1B, to compensate for the imbalance caused by the toothed body 5, the compound gear 10 has a balancing weight 9. The balancing weight 9 is in the form of a separate body (in this case made of steel) which, in the assembled condition of the composite gear 10 (see fig. 1A), is located completely within the basic body 1. For example, the balancing weight 9 may be held in the base body 1 in the radial direction R by a pin, which is not shown here and is intended to be introduced into the pin hole 9' formed in the base body 1.

As already mentioned, compound gear 10 includes a hub 2 for defining the timing of compound gear 10. In this case, the hub 2 is in the form of an insert which is held in the base body in a form-fitting manner (by means of the external toothing 8).

Finally, fig. 1C shows the hub 2 in detail. The hub 2 has an internal toothing 4, for example with eight teeth 4', which are distributed uniformly over the inner circumference IU of the hub. The teeth 4' are arranged at 45 degree intervals, which substantially corresponds to the central angle ZW of the first circular arc K1 of the toothed body 5. As a result, the gear can be mounted in the transmission unit 30 of the hammer drill 100 in such a way that only that part of the ring gear 3 which is formed by the toothed body 5 is directly subjected to the increased torque of the percussion mechanism 20 of the hammer drill 100.

Fig. 2A now shows such an electro-pneumatic hammer drill 100. The electric hammer drill preferably has a brushless electric motor 40 which is connected to the impact mechanism 20 via a transmission unit 30. The impact mechanism has, in its own right, a piston 21 which acts on a pneumatic spring 23. The transmission unit 30 has a compound gear 10 which is driven about a gear rotation axis D. In fig. 2B, a diagram of the torque in the transmission unit 30 (more precisely at the measuring point 35) versus the crank angle KW is shown. The crank angle KW is defined about the rotational axis D. It is apparent that in the range of 0 degrees to 180 degrees, the torque M is low (Mmin) and the torque peak (Mmax) is generated in the range of 280 degrees to 320 degrees. This torque is absorbed by the toothed body 5, which has an exemplary central angle ZW of 40 degrees.

List of reference numerals

1 base body

2 hub insert

3 ring tooth part

4 internal tooth part

4' tooth

5 toothed body

6, 6' cut-out

7 groove

8 external tooth

9 balance weight

9' pin hole

10 composite gear

20 impact mechanism

21 piston

23 pneumatic spring

30 drive unit

35 measuring point

40 electric motor

100 hammer drill

D axis of rotation

K1 first arc

Second arc of K2

KW crank angle

M torque

M1 first Material

M2 second Material

R radial direction

IU inner circumference

ZW central angle