Eccentric drive for power tools

Abstract

The invention relates to a power tool, in particular a tube press, comprising a drive, an output shaft, a threaded spindle drive and a linear actuator, wherein a torque generated by the drive can be transmitted to the linear actuator via the output shaft and the threaded spindle drive connected to the output shaft. The power tool comprises an eccentric gear for torque adjustment between the drive and the threaded spindle drive, wherein the eccentric gear comprises a drive eccentric which can be driven by the drive, an eccentric gear wheel which can be driven by the drive eccentric, and a compensation coupling which can be driven by the eccentric gear wheel and serves to transmit torque from the eccentric gear wheel to the output shaft.

Description

Technical Field

[0001] The present invention relates to a power tool, particularly a pipe press, comprising a driver, an output shaft, a threaded spindle driver, and a linear actuator, wherein torque generated by the driver can be transmitted to the linear actuator via the output shaft and the threaded spindle driver connected to the output shaft. Background Technology

[0002] Various power tools are known in the prior art for deformation and cutting processes. These specialized power tools can be used, for example, to cut reinforcing bars, mechanically connect pipes, or press hose clamps. Mechanical connection tasks also include so-called crimping, flanging, and extrusion.

[0003] To achieve the high pressing force required for steel pipe crimping, commercially available crimping machines, for example, have a press head driven by a cylinder. Here, the cylinder is typically hydraulically driven to move the press head. An electric motor then drives a hydraulic pump, which outputs the linear motion of the cylinder. Alternatively, commercially available mechanical pressing / cutting and crimping tools replace the hydraulic system, generating pressing pressure by means of a threaded spindle drive and an electric motor. Here, the rotational motion of the electric motor is converted into linear motion by means of a threaded spindle. These power tools typically include a transmission mechanism connecting the spindle and the electric motor and used to reduce the required motor torque, thereby enabling a smaller motor size.

[0004] However, existing power tools with hydraulically driven linear actuators are often too complex to develop, too large or too long to operate, inefficient, and too heavy. Furthermore, existing power tools with hydraulically driven linear actuators require relatively long times for a single work cycle, which may be, for example, a deformation cycle or a cutting cycle. Summary of the Invention

[0005] Therefore, the object of the present invention is to provide a power tool, particularly a pipe press, including a driver, an output shaft, a threaded spindle driver, and a linear actuator, to solve the above-mentioned problems.

[0006] In particular, this objective is achieved by providing a power tool of the present invention, especially a pipe press, which includes: a driver, an output shaft, a threaded spindle driver, and a linear actuator, wherein the torque generated by the driver can be transmitted to the linear actuator via the output shaft and the threaded spindle driver connected to the output shaft.

[0007] According to the present invention, the power tool includes an eccentric transmission device for torque adjustment between the driver and the threaded spindle driver, wherein the eccentric transmission device includes a drive eccentric member that can be driven by the driver, an eccentric gear that can be driven by the drive eccentric member, and a compensating coupling that can be driven by the eccentric gear and is used to transmit torque from the eccentric gear to the output shaft.

[0008] The compensating connector can be configured here as a torsional rigid compensating connector.

[0009] Using eccentric drives eliminates the need for hydraulically driven linear actuators, thus simplifying the development of power tools and making them smaller, more efficient, and easier to operate. Furthermore, eccentric drives significantly shorten the duration of work cycles. Additionally, they allow for relatively high gear ratios to be achieved in a single transmission stage. Moreover, they enable very high gear ratios (i.e., for example, from 1 to 1000) to be achieved in a single gear stage.

[0010] An eccentric transmission device can also be called a circular thrust transmission device or a cycloidal transmission device. Furthermore, an eccentric transmission device can also be called a planetary transmission device, which is configured without a sun gear and directly drives the planetary gears via an eccentric element.

[0011] The eccentric transmission is essentially configured as a planetary transmission, although the sun gear can be omitted. The eccentric gear of the eccentric transmission is directly driven by the eccentric component.

[0012] According to an advantageous embodiment of the invention, an involute tooth portion may exist between the ring gear and the eccentric gear fixedly connected to the housing.

[0013] Instead of the sliding motion that occurs at the corresponding contact points of the teeth in ring gears and eccentric gears, a more efficient rolling motion is generated by using involute teeth. Furthermore, this minimizes the number of rolling bearings necessary on the top of the ring gear or on the ring gear itself.

[0014] The outer diameter of the eccentric gear basically corresponds to the inner diameter of the ring gear. The transmission ratio between the eccentric gear and the ring gear is maximized when the difference in the number of teeth between them is minimal. Here, the minimum value is a difference in the number of teeth of one.

[0015] According to another advantageous embodiment of the invention, the compensating coupler can be configured as a parallel crank coupler.

[0016] This crank coupling can also be called a pin coupling or a slider coupling.

[0017] By using a parallel crank coupling, the relatively slow rotational speed of the output shaft relative to the eccentric gear is not limited.

[0018] According to another advantageous embodiment of the invention, the eccentric transmission device can be configured as a single stage, and the transmission ratio is 1:10 to 1:100.

[0019] According to another advantageous embodiment of the invention, the eccentric gear and the ring gear may have a tooth number difference of 1 to 2 teeth.

[0020] According to another advantageous embodiment of the invention, the ring gear may have between 20 and 200 teeth.

[0021] According to another advantageous embodiment of the invention, the maximum inner diameter of the ring gear can be between 20 mm and 200 mm.

[0022] According to another advantageous embodiment of the invention, the ring gear of the eccentric transmission device can be rotatably mounted in the housing.

[0023] According to another advantageous embodiment of the invention, the eccentric transmission device can be at least partially constructed of a sintered metal material. The use of a sintered material allows for improved slidability of the components, that is, particularly within the eccentric transmission device.

[0024] According to another advantageous embodiment of the invention, the eccentric drive can be at least partially constructed of a polymer. The use of polymers allows for more advantageous and easier production of the eccentric drive. Furthermore, imbalance and friction can be reduced, and efficiency can be improved.

[0025] Further advantages will become apparent from the following description of the accompanying drawings.

[0026] Various exemplary embodiments of the present invention are shown in the accompanying drawings.

[0027] The accompanying drawings and description contain many combinations of features. Those skilled in the art will also readily consider these features individually and combine them to produce useful further combinations. Attached Figure Description

[0028] In the accompanying drawings, identical and similar parts and components are indicated by the same reference numerals.

[0029] Specifically:

[0030] Figure 1 A side view of a power tool in the form of a tube press is shown;

[0031] Figure 2A cross-sectional side view of a power tool in an exemplary form of a tube press is shown, the power tool having a driver, an output shaft, a threaded spindle driver, a linear actuator, and an eccentric drive.

[0032] Figure 3 A perspective cross-sectional view of a power tool in an exemplary form of a tube press is shown, the power tool having a driver, an output shaft, a threaded spindle driver, a linear actuator, and an eccentric drive.

[0033] Figure 4 A three-dimensional cross-sectional view of the eccentric transmission device, a portion of the output shaft, and the first and second bearings is shown.

[0034] Figure 5 A front view of an eccentric drive mechanism is shown, which has a drive eccentric element, an eccentric gear, and a ring gear.

[0035] Figure 6 A three-dimensional cross-sectional view of the driver, output shaft, first bearing, drive eccentric component, and eccentric gear is shown.

[0036] Figure 7 A cross-sectional side view of the driver, output shaft, first bearing, drive eccentric component, and eccentric gear is shown.

[0037] Figure 8 A perspective view of a drive eccentric component with a compensating counterweight is shown;

[0038] Figure 9 A side view of the drive eccentric component with compensating counterweight is shown; and

[0039] Figure 10 A cross-sectional side view of the drive eccentric component is shown. Detailed Implementation

[0040] Figures 1 to 3 A power tool 1 according to the invention is shown, which is a pipe press in an exemplary embodiment. Instead of being an embodiment of a pipe press, the power tool 1 can also be implemented as any other cutting or shaping tool. In particular, the power tool 1 according to the invention can also be implemented as a dispensing device for chemicals such as adhesives or sealing compounds. Such a dispensing device can also be called a dispenser.

[0041] like Figure 1 It can be seen that the power tool 1 implemented as a pipe press basically has a housing 2, tool accessories 3 and power supply 4.

[0042] The housing 2 of the power tool 1 is basically cylindrical and includes a front end 2a, a rear end 2b, a left side surface 2c, a right side surface 2d, an upper side 2e, and a lower side 2f. The central portion 2g of the housing 2 serves as a handle to allow the power tool 1 to be held and controlled. Figures 1 to 3 Only the left surface 2c is shown in the image.

[0043] The power source 4 is located at the rear end 2b of the housing 2 of the power tool 1. In this exemplary embodiment, the power source 4 is in the form of a rechargeable battery (also referred to as a power pack or battery). The power source 4, in the form of a rechargeable battery, can be detachably connected to the rear end 2b of the housing 2 of the power tool 1 via an interface 5. Power is supplied to the power tool 1 or its power-consuming devices by means of the rechargeable battery 4.

[0044] In an alternative embodiment of the invention, the power source 4 of the power tool 1 may also be implemented as a cable for connecting the power tool 1 to the mains power source (i.e., an electrical socket).

[0045] Tool fitting 3 for removably receiving and holding tool 6 is positioned at the front end 2a of housing 2 of power tool 1. In this exemplary embodiment, tool 6, in the form of a deformable tool, is positioned at tool fitting 3. In this exemplary embodiment, deformable tool 6 is implemented as a so-called indenter. The deformable tool 6 implemented as an indenter is primarily used for processing, and particularly deforming, pipelines (i.e., pipes or fittings). Pipelines are not shown in the drawings.

[0046] The power switch 7 is located on the lower side 2f of the housing 2 of the power tool 1. The power tool 1 can be started and stopped by means of the power switch 7.

[0047] The driver 8, drive shaft 9, eccentric transmission 10, output shaft 11, threaded spindle driver 12, and linear actuator 13 are substantially located inside the housing 2 of the power tool 1. In this exemplary embodiment, the driver 8 is implemented as a brushless electric motor.

[0048] like Figure 2 , Figure 3 , Figure 6 and Figure 7 As shown, the driver 8, implemented as a brushless electric motor, is connected to the eccentric transmission 10 via a drive shaft 9. Through the connection with the drive shaft 9, the torque generated in the driver 8 is transmitted from the driver 8 to the eccentric transmission 10.

[0049] The speed ratio between the driver 8 and the output shaft 11 can be generated by means of the eccentric transmission device 10.

[0050] Especially Figure 4As shown, the eccentric transmission device 10 also essentially includes a drive eccentric element 14, an eccentric gear 15, a ring gear 16, and a compensating coupling 17. See also Figures 8 to 10 The drive eccentric element 14 has a compensating counterweight 18 (also referred to as a balancing counterweight or counterweight), which is connected to the driver 8 via the drive shaft 9. A bearing 30 is positioned between the drive eccentric element 14 and the driver 8, see [reference needed]. Figure 6 and Figure 7 The eccentric gear 15 includes an aperture 15a for the ball bearing 19. The drive eccentric member 14 is fitted into the ball bearing 19 and thereby connected to the eccentric gear 15 to rotate together with it. The rotation of the drive eccentric member 14 in the rotational direction R also causes the eccentric gear 15 to rotate accordingly in an oscillating motion.

[0051] Furthermore, the eccentric gear 15 is positioned within the ring gear 16. The ring gear 16 is fixedly connected to the interior of the power tool 1's housing 2 in a rotational sense. See also Figure 5 The eccentric gear 15 and the ring gear 16 have involute teeth 20. The inner diameter DH of the ring gear 16 is 100 mm. According to an alternative embodiment, the inner diameter DH of the ring gear 16 can be between 20 mm and 200 mm.

[0052] Furthermore, the eccentric gear 15 includes a plurality of orifices 21 arranged in a circular pattern around the drive eccentric member 14. In the exemplary embodiment shown in the figure, the orifices 21 are in the form of eleven through holes. However, there may be more or fewer than eleven through holes. According to an alternative embodiment, the orifices 21 may also be formed as blind holes.

[0053] In this exemplary embodiment, the compensating coupler 17 is implemented as a parallel crank coupler having a connecting element 22. The respective through holes 21 of the eccentric gear 15 are used to receive the connecting element 22. In this exemplary embodiment, the connecting element 22 is implemented as a connecting pin.

[0054] Here, the diameter DA of the orifice 21, which is implemented as a through hole, is twice the diameter DK of the connecting element 22, which is implemented as a connecting pin.

[0055] Here, the diameter of the orifice 21 corresponds at least to the diameter of the connecting element 22 and to twice the value of the eccentricity E of the eccentric gear 15.

[0056] D 孔口 ≥ D 联接元件 + (2 x E)

[0057] D 孔口 Diameter of the orifice

[0058] D 联接元件 Diameter of the connecting element

[0059] E: Eccentricity of the eccentric gear.

[0060] Therefore, the compensating coupling 17 can be referred to as a parallel crank coupling, or alternatively as a pin or crank coupling.

[0061] like Figure 4 As can be seen, the free end 22a of each connecting pin 22 protrudes from the through hole 21 of the eccentric gear 15 in the direction of arrow A. The free end 22a of each connecting pin 22 is then connected to the output shaft 11 in such a way that torque can be transmitted from the connecting pin 22 of the compensating connector 17 to the output shaft 11.

[0062] The output shaft 11 has a substantially cylindrical shape. The output shaft 11 is mounted inside the housing 2 of the power tool 1 by means of a main bearing 23 and a secondary bearing 24. The main bearing 23 is implemented as a rolling bearing or a ball bearing, while the secondary bearing 24 is implemented as a sliding bearing. According to an alternative exemplary embodiment, both the main bearing 23 and the secondary bearing 24 can be implemented as rolling bearings or sliding bearings. According to an alternative embodiment, only a single bearing may be provided.

[0063] As described above, the output shaft 11 is connected to the compensating coupling 17 of the eccentric transmission device 10. The output shaft 11 is adjacent to the threaded spindle driver 12. Here, the threaded spindle driver 12 is connected to the output shaft 11. The rotational motion of the output shaft 11 can be converted into linear motion by means of the threaded spindle driver 12.

[0064] Especially from Figure 2 and Figure 3 As can be seen, the threaded spindle driver 12 is connected to the linear actuator 13.

[0065] The linear actuator 13 basically includes a compression spring 25 and a push rod 26. Here, the compression spring 25 serves as the return spring for the linear actuator 13.

[0066] A force flow diversion device 27 is provided at the linear actuator 13. With the help of the linear actuator 13 and the force flow diversion device 27, the linear force of the linear actuator 13 is transmitted to the tool accessory 3, so that the tool 6 in the form of a pressure head can move between the open position and the closed position.

[0067] The driver 8, implemented as an electric motor, can rotate at a speed between 10,000 rpm and 30,000 rpm at the maximum extension and retraction speed of the linear actuator 13. In particular, the driver 8 is provided with a speed between 15,000 rpm and 18,000 rpm.

[0068] List of reference numerals

[0069] 1 Power Tools

[0070] 2 shells

[0071] 2a Front end of the shell

[0072] Rear end of 2b housing

[0073] The left side surface of the 2c housing

[0074] The right side surface of the 2D shell

[0075] The upper side of the 2e housing

[0076] 2f lower side of the shell

[0077] 3 Tools and Accessories

[0078] 4 power supplies

[0079] 5 interfaces

[0080] 6 tools

[0081] 7 Enable Switch

[0082] 8 drives

[0083] 9 drive shafts

[0084] 10 Eccentric Transmission Device

[0085] 11 output shaft

[0086] 12-thread spindle drive

[0087] 13 linear actuators

[0088] 14 drive eccentric components

[0089] 15 eccentric gears

[0090] The orifice in the 15a eccentric gear

[0091] 16 ring gears

[0092] 17 Compensation Connector

[0093] 18 Compensating counterweights

[0094] 19 ball bearings

[0095] 20 Involute teeth

[0096] 21. The orifice in the eccentric gear

[0097] 22 Connecting elements

[0098] 22a Free end on connecting element

[0099] 23 main bearing

[0100] 24 sets of bearings

[0101] 25 compression spring

[0102] 26 thrust rods

[0103] 27. Force flow steering device

[0104] 30 bearing

[0105] Diameter of DA orifice

[0106] DK connector diameter

[0107] Inner diameter of DH ring gear

[0108] Eccentricity of E-type eccentric gear

Claims

1. A power tool (1) comprising a driver (8), an output shaft (11), a threaded spindle driver (12), and a linear actuator (13), wherein, The torque generated by the driver (8) can be transmitted to the linear actuator (13) via the output shaft (11) and the threaded spindle driver (12) connected to the output shaft (11). The feature is that it includes an eccentric transmission device (10) for torque adjustment between the driver (8) and the threaded spindle driver (12), wherein the eccentric transmission device (10) includes a drive eccentric member (14) drivable by the driver (8), an eccentric gear (15) drivable by the drive eccentric member (14), and a compensating connector (17) drivable by the eccentric gear (15) and used to transmit torque from the eccentric gear (15) to the output shaft (11), the compensating connector (17) being implemented with a connecting element. (22) Parallel crank coupling, the free end (22a) of each connecting element (22) of the compensating coupling protrudes from the orifice (21) of the eccentric gear (15), and the free end (22a) of each connecting element (22) is further connected to the output shaft (11) in such a way that torque can be transmitted from the connecting element (22) of the compensating coupling (17) to the output shaft (11), an involute tooth portion (20) is included between the ring gear (16) fixedly connected to the housing (2) and the eccentric gear (15), and the eccentric gear (15) is positioned in the ring gear (16).

2. The power tool (1) as described in claim 1. Its features are, The eccentric transmission device (10) is configured as a single stage, and the transmission ratio is from 1:10 to 1:

100.

3. The power tool (1) as described in claim 1. Its features are, The eccentric gear (15) and the ring gear (16) have a tooth difference of 1 to 2 teeth.

4. The power tool (1) as described in claim 1. Its features are, The ring gear (16) has between 20 and 200 teeth.

5. The power tool (1) as described in claim 1. Its features are, The maximum inner diameter of the ring gear (16) is between 20 mm and 200 mm.

6. The power tool (1) as described in claim 1. Its features are, The ring gear (16) of the eccentric transmission device (10) is rotatably mounted in the housing (2).

7. The power tool (1) as described in claim 1. Its features are, The eccentric drive device (10) is at least partially made of sintered metal material.

8. The power tool (1) as described in claim 1. Its features are, The eccentric drive (10) is at least partially made of polymer.

9. The power tool (1) as described in claim 1 or 2. Its features are, The eccentric gear (15) includes at least one aperture (21) for receiving a connecting element (22), wherein the diameter (DA) of the aperture (21) corresponds at least to the diameter (DK) of the connecting element (22) and to twice the value of the eccentricity (E) of the eccentric gear (15).

10. The power tool (1) as described in claim 1. Its features are, The power tool (1) is a pipe press.

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