CN107191497B

CN107191497B - Sleeve, shaft-sleeve connection and hand-held power tool having a shaft-sleeve connection

Info

Publication number: CN107191497B
Application number: CN201611273131.2A
Authority: CN
Inventors: Z·科奇什
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2015-12-30
Filing date: 2016-12-30
Publication date: 2021-10-26
Anticipated expiration: 2036-12-30
Also published as: CN107191497A; DE102016225938A1

Abstract

The invention proceeds from a bushing having a bushing axis and a multi-ribbed inner contour which is designed for the form-locking transmission of a torque. It proposes: the multi-edged inner contour is designed to be conically widened in an axially distal region relative to an axially proximal region in which the multi-edged inner contour extends parallel to the sleeve axis, in particular, an insertion surface is provided between two adjacent edges of the conically widened multi-edged inner contour, which insertion surface forms, in particular centrally, a ridge line extending obliquely to the sleeve axis between the adjacent edges, which ridge line is arranged, in particular, closer to the sleeve axis than to the adjacent edges.

Description

Sleeve, shaft-sleeve connection and hand-held power tool having a shaft-sleeve connection

Technical Field

The invention relates to a sleeve, a shaft-sleeve connection and a hand-held power tool having a shaft-sleeve connection.

Background

DE 29809694U 1 discloses a polygonal, form-fitting shaft-sleeve connection having an entry ramp arranged on the sleeve, which entry ramp enables a polygonal outer polygonal contour of the shaft to be rotated appropriately about the axis of rotation or the longitudinal axis of the sleeve during axial connection with the sleeve, so that the polygonal outer contour is perfectly aligned with the polygonal inner contour of the sleeve, so that the shaft can always be inserted axially into the sleeve in order to be able to transmit torque in the inserted state, without having to be rotated manually beforehand in order to perfectly align the polygonal outer contour of the shaft and the polygonal inner contour of the sleeve with one another. However, the entry ramp is structurally complex and easily damaged, and moreover a sharp entry ramp poses a certain risk of injury to the user.

Disclosure of Invention

The invention relates to a sleeve having a sleeve axis and a multi-edged inner contour, in particular distributed over the circumference of the sleeve, which is designed to transmit torque in a form-fitting manner.

It proposes: the multi-edge inner contour widens conically in the axial distal region relative to an axial proximal region, in which the multi-edge inner contour is formed substantially parallel to the sleeve axis and advantageously tangentially thereto. Furthermore, an insertion surface or an insertion rotation-assisting surface is provided between two edges of the conically widening multi-edged inner contour, in particular between two edges adjacent in the circumferential direction of the sleeve. The insert surface forms a ridge line intermediate adjacent edges. The ridge is radially closer to the sleeve axis than the adjacent edge.

For example, a plurality of, advantageously half, in particular all adjacent edges of the polygonal inner contour have such insertion surfaces, which each have a ridge line. A multi-edged inner contour is understood to mean a polygonal inner contour of the sleeve, which is provided for the transmission of a torque of a shaft connected to the sleeve in a form-fitting manner and/or for the transmission of a torque to a shaft connected to the sleeve, for example a shaft having a multi-edged outer contour corresponding to the proximal multi-edged inner contour of the sleeve. This configuration of the sleeve makes it possible to provide a shaft-sleeve connection which can be connected to one another during the axial connection process, irrespective of whether the shaft and the sleeve or the shaft axis and the sleeve axis are initially in rotational alignment with one another, in particular when the shaft and the sleeve are not in perfect alignment, without additional manual rotation of the polygonal interlocking connection of the aligned shaft and sleeve relative to one another.

Furthermore, it is proposed that: the ridge extends obliquely to the sleeve axis and widens conically in particular in relation to the axial proximal region in the case of the distal end of the sleeve. Instead of a constant conical widening, the ridge can also have a varying widening, so that the torsional properties are adjustable during the axial connection process of the sleeve and the shaft toward one another or into one another. If the polygonal connecting structures are not yet perfectly aligned with one another when the shaft is inserted into the sleeve or the sleeve is slipped onto the shaft, a twisting of the shaft and the sleeve relative to one another, which is proportional to their axial insertion depth or the slip depth, is advantageously achieved by the conically widening ridges. Although the polygonal inner and outer contours of the shaft and sleeve are not in full rotational alignment with one another, they can be pushed or pushed into one another without becoming caught or snagged. Furthermore, it is possible to ensure that the sleeve and the shaft are inserted starting from an angular position in which the axes of the shaft and the sleeve deviate from each other at least to a limited extent.

Furthermore, it is proposed that: the taper of the widening of the ridge line is less than the taper of the widening of the adjacent edge of the widening multi-edge inner profile. In this way, a reliable guidance of the corner points or insertion points of the shaft or a reliable screwing-in of the polygonal outer contour of the shaft is achieved when the shaft and the sleeve are axially connected, so that a complete coincidence with the corresponding polygonal inner contour of the sleeve is achieved.

Furthermore, it is proposed that: the insertion surface between adjacent edges of the widened multi-edged inner contour projects relative to the sleeve axis. This allows an initially gentle and finally accelerated screwing-in of the shaft and the sleeve to be achieved during the axial connection process at constant speed.

Furthermore, it is proposed that: the insertion surface between the ridge line and the adjacent edge is designed to be flat, in particular as a flat surface pair. This reduces the complexity of manufacturing the insert face. A reliable and stable twisting is likewise achieved for the complete alignment of the polygonal inner contour and the polygonal outer contour. But it is also possible: the surface pairs are designed to be concave, so that, for example, when the shaft and the sleeve are axially connected at a constant speed, an initial acceleration and a final deceleration of the screwing-in can be achieved. The insertion face may be configured to widen gradually from the proximal end region towards the distal end of the sleeve, with reference to the radial distance relative to the sleeve axis. The widening may be greater than the widening of the ridge line and less than the widening of the adjacent edge.

Furthermore, it is proposed that: the insertion surfaces are each configured mirror-symmetrically with respect to a plane of symmetry extending through the ridge line and the sleeve axis.

Furthermore, a shaft-sleeve connection having the above-described sleeve and having a shaft with a multi-edged outer contour which is configured complementarily to the proximal multi-edged inner contour of the sleeve is claimed. The fit between the proximal multi-sided inner profile and the multi-sided outer profile is, for example, a clearance fit. Not only the sleeve but also the shaft can have an insertion chamfer at its distal end which makes the connection easy.

In addition, a hand-held power tool, for example a screwdriver, having the sleeve and/or the shaft-sleeve connection is claimed, which in particular has a bit receptacle embodied as the sleeve, which is preferably used to receive a bit shank embodied as the shaft.

Furthermore, a garden appliance, for example a motor-driven garden appliance, is claimed, which has the above-mentioned sleeve and/or the above-mentioned shaft-sleeve connection. The garden appliance may be embodied detachably, for example for extending the range of action, for shortening for keeping, etc., or for receiving different accessories, such as hedge shears accessories, trimmer accessories, chain saw accessories or the like. The garden appliance may have a detachable protective tube and a driving or driven shaft detachably inserted in the protective tube.

Since the shaft-sleeve connection is typically arranged within the protective tube or is retracted within the protective tube from a separating surface of the detachable protective tube, a self-alignment of the shaft and the sleeve, which is achieved by the insertion aid, or an automatic rotation relative to one another is particularly advantageous. The shaft and the sleeve advantageously can be arranged in a protected manner completely within the protective tube and/or can be arranged to be retracted relative to the parting plane of the protective tube, without the user having to carry out the connection by eye on the interface of the shaft and the sleeve during the connection.

Furthermore, a garden appliance or a hand-held power tool is claimed, which has a drive unit and an interface for receiving exchangeable accessories. The garden tool or hand-held power tool has at least one drive shaft which can be connected to the output shaft at least via the above-mentioned sleeve, in particular via the above-mentioned shaft-sleeve connection. For this purpose, the drive or driven shaft has at least one end the above-described sleeve, which is advantageously connected to the drive or driven shaft in a material-locking, friction-locking or similar manner. The drive shaft or the driven shaft can be detachably connected at least by the sleeve and/or the shaft-sleeve connection in at least one protective tube, in particular in a protective tube which is detachable in the region of the shaft-sleeve connection. The drive shaft and the driven shaft can also be inserted in the at least one protective tube. The protective tube is fastened, for example, to a motor housing of the hand-held power tool or the garden appliance, and the further protective tube or a further part of the protective tube is fastened to an accessory of the hand-held power tool or the garden appliance.

The drive shaft and the driven shaft can be coupled to each other in a simple manner by automatic rotational alignment of the sleeve and the shaft when the sleeve and the shaft are axially connected. It is also possible to connect different garden-tool accessories that can be removed in a simple, safe and reliable manner. The shaft-sleeve connection according to the invention is particularly suitable for garden appliances having at least one protective tube and having a drive or driven shaft inserted therein, for example a multi-functional garden appliance on which, for example, trimmer attachments, pole trimmer attachments, hedge trimmer attachments, grass trimmer attachments or pruner attachments can be mounted, and/or also for garden appliances which are embodied in two parts, for example in the form of trimmers, trimmer cutters or the like, in particular for ease of transport or for reducing the space required for storage.

Drawings

Other advantages result from the following description of the figures. In which embodiments of the invention are shown. The figures, description and claims all contain a number of combinations of features. Those skilled in the art can also, in a satisfactory manner, treat these features individually or combine them into other combinations of significance.

Figure 1 is a perspective view, longitudinal section and front view of the sleeve,

figure 2 is a perspective, side and front view of the shaft,

figure 3 is a view of the shaft-sleeve connection,

figure 4 shows a hand-held power tool with a sleeve as described above,

fig. 5 shows a garden appliance with a sleeve and/or a shaft-sleeve connection as described above.

Detailed Description

1a-c show a sleeve 10 according to the invention in three views; fig. 1a is a perspective view, fig. 1b is a longitudinal section view, and fig. 1c is a plan view of the distal end 12 of the sleeve 10. The sleeve 10 has a sleeve axis 14 and a multi-edge inner contour 18a, b distributed over the circumference 16 of the sleeve 10. The multi-edged inner contour 18a, b is hexagonal in configuration and thus has six edges 20a, b. It is also conceivable for the inner polygonal profile 18a, b to be any other polygonal multi-edged profile, the number of edges 20a, b of which differs from six, for example a multi-edged inner profile 18a, b with three to twelve edges 20 or the like. The edge 20a extends parallel to the sleeve axis 14 in the proximal region 28. Starting from the proximal region 28, the edge 20b widens conically in the axial direction in the distal region 26. The widening of the edge increases from a first end 29 of the proximal region 28 facing the distal region 26 to the distal end 12 of the sleeve 10. The polygonal inner contour 18a is formed in the proximal end region 28 in such a way that it is provided for the transmission of the torque 22 from the sleeve 10 to the shaft 100 (see fig. 2) or vice versa in a form-fitting manner.

The widened polygonal inner contour 18b in the distal region 26 of the sleeve 10 is designed as an insertion aid 27, in particular as an insertion rotation aid. An insertion surface 30, in particular an insertion surface of revolution, is provided between adjacent edges 20b of the widened polygonal inner contour 18 b. Insert surface 30 forms a ridge 32 intermediate adjacent edges 20b of widened multi-edged inner contour 18 b. With reference to a common point on the sleeve axis 14, the ridge line 32 is radially closer to the sleeve axis 14 than the adjacent edge 20b of the widened multi-ribbed inner profile 18 b. The number of ridges 32 corresponds to the number of adjacent edges 20a, b. Thus, fig. 1a-c show six ridge lines 32, similar to the polygonal multi-edged inner profile 18a, b of a polygon with six edges 20a, b. However, a smaller number of insertion surfaces 30 and ridges 32 is also conceivable. For example, only one insertion surface with one ridge 32 or three insertion surfaces 30 with three ridges 32 can be provided between adjacent edges 20b of the widened hexagonal multi-edged inner contour 18 b. Advantageously, the three ridges 32 are arranged at an angle of 120 ° apart with respect to the circumferential direction 16. In this way, a centering and insertion rotation can be achieved with fewer ridges 32 than the edges 20a, b when connecting the shaft 100 to the sleeve 10. Other combinations of inset surface 30 and ridge line 32 numbers other than the number of edges 20a, b of multi-edged inner profiles 18a, b are also contemplated.

In this embodiment, the ridge 32 is embodied in the distal end region 26 of the sleeve 10 axially from the first of the proximal end region 28The end 29 widens conically as far as the distal end 12. The conical widening of the ridge line 32 has a smaller inclination relative to the sleeve axis 14 than the inclination of the adjacent edge 20b of the widened multi-edged inner contour 18b relative to the sleeve axis 14. The insertion surface 30 between the ridge 32 and the adjacent edge 20b of the widened polygonal inner contour 18b is designed as a flat, in particular planar, surface pair: (

) Or part of the surfaces facing each other. The insertion surface may be convex, concave, or of any shape relative to the sleeve axis 14. In the case of a flat or concave design, the ridge 32 forms a further edge 34. The ridge 32 or edge 34 intersects the sleeve axis 14 at an acute angle. The insertion surface 30 is configured as a mirror-symmetrical pair of surfaces, with reference to the symmetry plane 24 extending through the respective ridge line 32 and the sleeve axis 14.

By virtue of the fact that the ribs 20a extend parallel to the sleeve axis 14 in the proximal region 28, a multi-ribbed inner contour 18a for transmitting the torque 22 is formed in this region 28. The torque transmission surfaces 38 between adjacent edges 18a are at least substantially likewise embodied flat. The torque transmission surface corresponds in this case to the greatest extent to the driving contour of a conventional hexagon socket head.

In an intermediate region 40 between the distal end 12 and the proximal second end 42 of the sleeve 10, the sleeve 10 has an axial limiting wall 44. A further receptacle 46 for a drive or driven shaft extends between the proximal second end 42 and the delimiting wall 44, viewed axially. The further receptacle 46 is provided in this case with a transition fit with respect to the drive shaft or the driven shaft. Furthermore, the drive shaft or the driven shaft is connected to the sleeve 10 in a material-locking manner. However, it is also conceivable to have a further shaft-sleeve connection with a corresponding fit, or to form the sleeve 10 integrally with the drive or driven shaft. The outer diameter 48, 50 of the sleeve 10 is reduced in the region of the bounding wall 44 via a chamfer (Phase) 52. The outer diameter 50 in the region of the further receptacle 46 is therefore smaller than the outer diameter 48 in the region of the multi-edge inner contour 18a, b. The chamfer 52 and/or the outer contour of the sleeve 10 can be used to center the sleeve 10 within the protective tube 402. The limiting wall 44 also has a through opening 54, through which air can escape when connecting the drive or driven shaft to the sleeve 10. The radially circumferential edge 56 is chamfered at the distal end 12, the delimiting wall 44 and the proximal second end 42 of the sleeve 10.

2a-c illustrate the shaft 100 in three views; fig. 2a is a perspective view, fig. 2b is a side view, and fig. 2c is a front view of the distal end 102 of the shaft 100. Shaft 100 has a shaft axis 104 and a multi-faceted outer profile 106 corresponding to proximal multi-faceted inner profile 18a of sleeve 10. The engagement of proximal polygonal inner contour 18a with polygonal outer contour 106 is embodied as a clearance fit. The polygonal outer contour 106 of the shaft 100 is in this case hexagonal in shape corresponding to the proximal polygonal inner contour 18a of the sleeve 10 and has six outer edges 108a extending parallel to the shaft axis 104. The surface 110 between the outer edges 108a is embodied flat. The faces extend tangentially and axially relative to the sleeve axis 104. The shaft 100 has a chamfer 112 in the region of the distal end 102. The chamfering 112 is carried out in such a way that the polygonal outer contour 106 remains unchanged despite the chamfering. An insertion point 118 is formed on a radial edge 116 extending in the circumferential direction 114 of the shaft 100. The number of insertion points 118 corresponds to the number of outer edges 108a of multi-edged outer contour 106. The first region 120 of the shaft 100 is used for torque transmission with the shaft 100 to be connected with the sleeve 10. The first region 120 may be made of a solid material, for example, and may in particular be made of an at least surface-hardened solid material. The second region 122 of the shaft 100 is hollow. This second region 122 serves as a receptacle 124 for the connection to a drive or driven shaft and is implemented according to this embodiment analogously to the receptacle 46 of the sleeve 10. The outer edge 108b of the polygonal outer contour 106 is interrupted in this second region 122. The second region 122 may also be used to center the shaft 100 within the protective tube 402.

Fig. 3 shows a sleeve 10 and a shaft 100 that may be joined to form a shaft-sleeve connection 200. Irrespective of whether the sleeve 10 and the shaft 100 are rotationally aligned with one another, when the sleeve 10 and the shaft 100 are axially inserted into one another, the conically widening polygonal inner contour 18b of the sleeve 10, via the insertion surface 30 and the conically widening ridge 32, causes the sleeve 10 and the shaft 100 to rotate 202 relative to one another in such a way that the widened polygonal inner contour 18b and the polygonal outer contour 106 are rotationally aligned with one another: outer multi-edged profile 106 is perfectly aligned with inner proximal multi-edged profile 18a so that they can be axially inserted into each other for torque transmission.

The process of interconnecting the sleeve 10 and the shaft 100 will be described in detail below. It is assumed that proximal multi-faceted inner profile 18a of sleeve 10 and multi-faceted outer profile 106 of shaft 100 are not initially fully rotationally aligned with one another. Furthermore, the angular positions 204 of the shaft axis 104 and the sleeve axis 14 may also differ from one another at least to a limited extent. When the sleeve 10 and the shaft 100 are axially inserted, the at least one insertion point 118 of the shaft 100 encounters the ridge 32 conically widening toward the distal end 12 of the sleeve 10 or the at least one insertion surface 30 of the conically widening multi-ribbed inner contour 18b of the sleeve 10. When the shaft 100 is pushed further axially into the sleeve 10, the ridge 32 tapering conically towards the first end 29 of the proximal region 28 and/or the insertion surface 30 arranged between the ridge 32 and the adjacent edge 20b results: at least one insertion point 118 is rotated in such a way that it is completely aligned with the edges 20a, b at the latest when the proximal region 28 is reached in the axial direction. Polygonal outer profile 106 is thus also perfectly aligned with proximal polygonal inner profile 18a, so that shaft 100 can be inserted into proximal region 28 of polygonal inner profile 18 a. The sometimes initially different angular position 204 of the sleeve axis 14 and the shaft axis 104 relative to one another can likewise be compensated until they are aligned parallel to one another. The shaft-sleeve connection 200 is connected in such a way that a positive transmission of force or torque between the polygonal inner contour and the polygonal outer contour of the sleeve 10 and the shaft 100 is ensured.

In order to avoid an axial cohesive connection, in particular to avoid an axial weld between the sleeve 10 and the shaft 100, an insert, for example a metal ring or a plastic part, can be provided between the distal end 102 of the shaft 100 and the central region 40 of the sleeve 10.

Fig. 4 shows a motor-driven screwdriver 300 having a bit receiving portion 302 with a socket 10.

Fig. 5 shows a garden appliance 400 in the form of a multi-purpose garden appliance 404. The garden appliance 400 has a drive unit 406 with a drive shaft 408 inserted in the protection tube 402. The drive shaft 408 can be connected to the sleeve 10 according to the invention in a form-fitting manner and is preferably inserted into the protective tube 402. The drive unit 406 is connected to an accessory 410 in the form of a trimmer accessory 412 provided with a tool 414 for cutting grass. Other accessories 410 may be mounted on the drive unit as described above. The garden appliance 400 may likewise be a hand-held power tool 300. The accessory 410 likewise has a protective tube 402 in which a driven shaft 416 is received, advantageously: is received through the protective tube or through a guide element received in the protective tube. At the end of the output shaft 416 facing the drive unit 406, a shaft 100 is arranged, which is advantageously connected to the output shaft 416 in a material-locking manner. Thereby forming the shaft-sleeve connection 200 of the present invention when the attachment 410 is connected to the drive unit 406.

Claims

1. A sleeve (10) having a sleeve axis (14) and a multi-ribbed inner contour which is designed for the form-fitting transmission of a torque (22), characterized in that the multi-ribbed inner contour is conically widened in an axial distal region (26) relative to an axial proximal region (28) in which it is designed parallel to the sleeve axis (14), an insertion surface (30) being provided between two adjacent edges (20b) of the conically widened multi-ribbed inner contour which are adjacent in the circumferential direction of the sleeve, said insertion surface forming a ridge (32) which runs obliquely to the sleeve axis (14).

2. The sleeve (10) of claim 1, wherein an inset surface (30) is provided between all adjacent edges (20b) of the widened multi-ribbed inner profile.

3. The sleeve (10) according to claim 1 or 2, characterized in that the ridge (32) widens conically with respect to the axial proximal region (28) with respect to the distal end (12) of the sleeve (10).

4. The sleeve (10) as claimed in claim 1 or 2, characterized in that the taper of the widening of the ridge line (32) is smaller than the taper of the adjacent edge (20b) of the widened multi-edged inner contour with respect to the sleeve axis (14); and/or

The ridges have a varying conical widening.

5. The sleeve (10) of claim 1 or 2, wherein the intervening surface (30) between adjacent edges (20b) of the widened multi-edged inner profile is configured to be convex with respect to the sleeve axis (14).

6. The sleeve (10) as claimed in claim 1 or 2, characterized in that the insertion surface (30) between two adjacent edges (20b) is configured as a pair of flat surfaces which are divided by the ridge line (32).

7. The sleeve (10) of claim 1 or 2, wherein the insertion face (30) is mirror symmetric about a plane of symmetry (24) extending through the ridge line (32) and the sleeve axis (14).

8. The sleeve (10) of claim 1 or 2, wherein the insertion surface forms the ridge line in the middle of the adjacent edge (20 b).

9. The sleeve (10) of claim 1 or 2, wherein the ridge line is radially closer to the sleeve axis (14) than the adjacent edge (20 b).

10. A shaft-sleeve connection (200) having a sleeve (10) according to one of claims 1 to 9 and having a shaft (100), wherein the shaft (100) has a multi-ribbed outer contour (106) which is configured complementarily to a multi-ribbed inner contour of the sleeve (10) in the axial proximal region.

11. Hand-held power tool (300) having at least one sleeve (10) according to one of claims 1 to 9 and/or having a shaft-sleeve connection (200) according to claim 10.

12. A garden appliance (400) with at least one sleeve (10) according to any one of claims 1 to 9 and/or with a shaft-sleeve connection (200) according to claim 10.

13. A garden appliance (400) as claimed in claim 12, characterized in that the garden appliance is a multi-purpose garden appliance (412), a trimmer or a free cutter.