Power tool with two motors

Abstract

A power tool, particularly a hammer drill, includes: a housing; a tool assembly for receiving and holding the tool; an impact device for generating impact pulses and transmitting these impact pulses to the tool; and a rotating device for generating torque and transmitting this torque to the tool, wherein a working axis is provided through the impact device. The power tool includes a first drive unit and a second drive unit, the first drive unit having a first rotation axis for driving the rotating device, and the second drive unit having a second rotation axis for driving the impact device, wherein the first drive unit and the second drive unit are arranged relative to each other within the housing such that the first rotation axis of the first drive unit is arranged at a first angle to the second rotation axis of the second drive unit and at a second angle to the working axis.

Description

Technical Field

[0001] The present invention relates to a power tool, particularly a hammer drill, comprising: a housing; a tool assembly for receiving and holding the tool; an impact device for generating impact pulses and transmitting these impact pulses to the tool; and a rotating device for generating torque and transmitting this torque to the tool, wherein a working axis is provided through the impact device. Background Technology

[0002] Various power tools in the form of hammer drills are known from the prior art. A hammer drill is a machine used to drill holes in mineral materials such as rock or concrete. The components of a hammer drill include a rotary drive and an impact mechanism. The rotary drive rotates the drilling tool, held by the hammer drill, about a rotational axis (also called the working axis). The impact mechanism generates impact pulses on the drilling tool along the working axis or impact axis. These impact pulses cause the cutting edge of the drilling tool to break the material being processed. Typically, these hammer drills known from the prior art have only one electric motor as the drive unit, which drives both the rotary drive and the impact mechanism via a relatively complex transmission system.

[0003] However, these existing power tools configured as hammer drills typically suffer from the following problem: the design of the transmission mechanism for distributing the torque generated by the drive element to the rotary drive and the impact mechanism is overly complex. "Complex" means that constructing and operating the transmission requires a large number of mechanical parts. Due to this complexity, the manufacture, production, and maintenance of such a transmission can be very expensive. Furthermore, the likelihood of such a complexly designed transmission failing or even completely malfunctioning is relatively high.

[0004] Therefore, the object of the present invention is to enable power tools, particularly hammer drills, to be used to solve the problems mentioned above. Summary of the Invention

[0005] This objective is achieved by the subject matter of independent claim 1, and in particular by providing a power tool, especially a hammer drill, comprising: a housing; a tool assembly for receiving and holding the tool; an impact device for generating impact pulses and transmitting these impact pulses to the tool; and a rotating device for generating torque and transmitting this torque to the tool, wherein a working axis is provided through the impact device.

[0006] According to the present invention, the power tool includes a first drive unit and a second drive unit. The first drive unit has a first rotation axis for driving the rotating device, and the second drive unit has a second rotation axis for driving the impact device. The first drive unit and the second drive unit are arranged relative to each other in the housing such that the first rotation axis of the first drive unit is arranged at a first angle to the second rotation axis of the second drive unit and at a second angle to the working axis.

[0007] Therefore, a single complex transmission component can be eliminated, making the power tool significantly simpler and more robust overall.

[0008] Advantageous configurations of the invention are described in the dependent claims.

[0009] According to an advantageous exemplary embodiment, both the first angle and the second angle can be configured as acute angles, wherein the value of the first angle can be from 50° to 80° and the value of the second angle can be from 10° to 30°.

[0010] Therefore, the mounting space within the housing can be used in a particularly efficient manner, and the power tool as a whole can have a compact configuration.

[0011] According to another advantageous exemplary embodiment, the first drive unit may include a first transmission device, and the second drive unit may include a second transmission device.

[0012] This method simply achieves that the transmission ratio from the first drive unit to the rotating device is unrelated to or independent of the transmission ratio from the second drive unit to the impact device.

[0013] According to an advantageous exemplary embodiment, the power tool may include a gear in the form of a bevel gear for connecting the first drive unit to the rotating device.

[0014] This allows for a near-optimal connection between the first drive unit and the rotating device.

[0015] Further advantages will become apparent from the following description of the accompanying drawings.

[0016] Various exemplary embodiments of the present invention are shown in the accompanying drawings.

[0017] The accompanying drawings, description, and patent claims 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

[0018] In the accompanying drawings, identical and similar parts are indicated by the same reference numerals. Specifically:

[0019] Figure 1 A cross-sectional side view of a power tool in the form of a hammer drill according to the present invention is shown. The power tool has a first drive unit and a second drive unit, an impact device, and a rotation device.

[0020] Figure 2 A cross-sectional side view of the first drive unit, the second drive unit, the impact device, and the rotating device is shown; and

[0021] Figure 3 A cross-sectional side view of the first drive unit and the second drive unit, the impact device and the first transmission device, and the rotating device and the second transmission device is shown. Detailed Implementation

[0022] Figure 1 A power tool 1 according to the present invention is shown, which is a hammer drill in an exemplary embodiment.

[0023] The power tool 1 (which is configured as a hammer drill) has a housing 2, a tool assembly 3, and a power supply unit 4.

[0024] The housing basically includes a front end 2a, a rear end 2b, a left side, a right side, an upper side, and a lower side.

[0025] As in Figure 1 As can be seen, the power unit 4 and the first handle 5 are located at the rear end 2b of the housing 2. The first handle 5 is used by the user to hold and guide the power tool 1, and can also be referred to as the main handle.

[0026] The user is not shown in the attached diagram.

[0027] In this configuration, the first handle 5 includes an activation switch 5a for activating the power tool 1. The activation switch 5a is connected to the control unit 6 via a wire L, such that when the activation switch 5a moves in the direction of arrow B, the power tool 1 transitions from a disabled mode to an activated mode. Conversely, when the activation switch 5a moves in the direction of arrow A by means of a spring (not shown in the figures), the power tool 1 transitions from an activated mode to a disabled mode. The control unit 6 itself is connected to the power supply unit 4 via a wire L for open-loop and closed-loop control of various functions.

[0028] Power unit 4 is used to supply electrical energy to power tool 1. In the exemplary embodiment considered and shown in the accompanying drawings, power unit 4 takes the form of a rechargeable battery (also referred to as a power pack or battery) that can be detached from power tool 1. According to an alternative exemplary embodiment (not shown in the drawings), power unit 4 may also be configured as a cable for releasably connecting power tool 1 to the power grid (i.e., an electrical outlet).

[0029] like Figure 1 As is also evident, the tool assembly 3 is positioned at the front end 2a of the housing 2. The tool assembly 3 is used to receive and hold the tool 7. In this exemplary embodiment, the tool 7 is configured as a drill. Alternatively, the tool 7 may also be configured as a chisel.

[0030] Furthermore, the second handle 8 is positioned at the front end 2a of the housing 2 of the power tool 1. Together with the first handle 5, the second handle 8 is used to further hold and guide the power tool 1, and the second handle may also be referred to as an auxiliary handle. The second handle 8 can be removed from the power tool 1 by means of a connecting device 8a.

[0031] As in Figure 2 and Figure 3 As can be seen, the control unit 6, the impact device 9, the rotating device 10, the first drive unit 11, the first transmission device 12, the second drive unit 13, and the second transmission device 14 are all basically contained within the housing 2.

[0032] As mentioned above, the control unit 6 is specifically used to perform open-loop and closed-loop control of the functions of the power supply unit 4. In addition, the control unit 6 performs separate open-loop and closed-loop control for various functions (e.g., the corresponding rotational speeds of the first drive unit 11 and the second drive unit 13).

[0033] The impact device 9 is used to generate impact pulses and transmit these impact pulses to the tool 7. For this purpose, the impact device basically includes a guide tube 15, an anvil 16, and an excitation piston 17. As shown in the accompanying drawings, the anvil 16 and the excitation piston 17 are positioned inside the guide tube 15. In this arrangement, the anvil 16 is located in front of the excitation piston 17 in the direction of arrow A. The guide tube 15 is connected to the tool assembly 3 to rotate together with the tool assembly. Therefore, when the guide tube 15 rotates about the working axis N in the rotational direction R, the tool assembly 3 also rotates about the working axis N in the rotational direction R, and the tool 7 held in the tool assembly 3 also rotates in the same way.

[0034] The rotating device 10 generates torque and transmits it to the tool 7 (configured as a drill) via the guide tube 15 and the tool assembly 3. For this purpose, the rotating device 10 essentially includes a gear 18 positioned around the guide tube 15 to rotate together with it. In this exemplary embodiment, the gear 18 is configured as a bevel gear. Furthermore, the rotating device 10 includes a pinion 19 (also referred to as a drive gear) corresponding to the bevel gear 18. As will be described in more detail below, the pinion 19 drives the bevel gear 18. The pinion 19 may be positioned directly on the end 20 of the rotor, or it may be positioned on the end 21a of the drive shaft 21 connected to the end 20 of the rotor.

[0035] Both the first drive unit 11 and the second drive unit 13 are in the form of electric motors and essentially include a stator and a rotor that can be driven around the stator. (As in...) Figure 2 and Figure 3 As can be seen, one end 20 of the rotor protrudes from the stator. In this arrangement, the first rotation axis S passes through the center of the rotor of the first drive unit 11. The rotor of the first drive unit 11 is configured to rotate about the first rotation axis S. The second rotation axis T passes through the center of the rotor of the second drive unit 13. The rotor of the second drive unit 13 is configured to rotate about the second rotation axis T.

[0036] A first drive unit 11, configured as an electric motor, is connected to the rotating device 10. A second drive unit 13, configured as an electric motor, is then connected to the impact device 9.

[0037] According to the first exemplary embodiment, refer to Figure 2 The first drive unit 11 is connected to the rotating device 10 via a drive shaft 21. The drive shaft 21 is fixed to the end 20 of the rotor protruding from the stator so that they rotate together. The rotational motion of the rotor is transmitted to the drive shaft 21. A pinion 19 is fixed to the end 21a of the drive shaft 21 opposite to the first drive unit 11. The arrangement of the pinion 19 relative to the bevel gear 18 is such that the rotational motion of the rotor of the first drive unit 11 is transmitted via the pinion 19 to the bevel gear 18, the guide tube 15, the tool assembly 3, and finally to the tool 7. The teeth of the pinion 19 engage with the teeth of the bevel gear 18 and drive the bevel gear. By means of the direct or indirect connection of the first drive unit 11, the rotational speed of the rotor and the rotational speed of the pinion 19 are directly transmitted to the bevel gear 18. The bevel gear 18 and the pinion 19 are configured to have a certain transmission ratio relative to each other. The gear ratio is determined by the number of teeth on pinion 19 and the number of teeth on bevel gear 18; or the ratio of the number of teeth on pinion 19 to the number of teeth on bevel gear 18. In this exemplary embodiment, the ratio of the number of teeth on pinion 19 to the number of teeth on bevel gear 18 is 0.2 (i.e., described in words as 0.2). The number of teeth on pinion 19 is the same as the number of teeth on bevel gear 18. According to an alternative embodiment, the ratio of the number of teeth on pinion 19 to the number of teeth on bevel gear 18 may be between 2 and 0.1. In particular, the ratio of the number of teeth on pinion 18 to the number of teeth on bevel gear 19 is between 0.1 and 0.5.

[0038] The length L of the first drive unit 11, drive shaft 21, and pinion 19 together is 100 mm. According to an alternative exemplary embodiment, the length L may be between 50 mm and 300 mm, and particularly between 80 mm and 200 mm.

[0039] According to the second exemplary embodiment, refer to Figure 3 The first drive unit 11 is connected to the rotating device 10 via a first transmission device 12. Here, the first transmission device 12 essentially includes a gear ring 22, a first planetary gear 23a and a second planetary gear 23b, a planetary gear carrier 24, a transmission ball bearing 25, and a drive shaft 21. The gear ring 22 is fixedly connected to the housing 2 of the power tool 1. Both the first planetary gear 23a and the second planetary gear 23b are positioned within the gear ring 22. A pinion 19 positioned at the end 20 of the rotor of the first drive unit 11 drives the two planetary gears 23a and 23b. The planetary gear carrier 24 is configured to rotate by means of the two planetary gears 23a and 23b. The planetary gear carrier 24 is then connected to the drive shaft 21, resulting in the drive shaft 21 also being configured to rotate. The transmission ball bearing 25 supports the drive shaft 21. Another pinion 19 is positioned at the end of the drive shaft 21 opposite to the planetary gear carrier 24. This pinion 19 transmits the rotational motion of the drive shaft 21 to the bevel gear 18 and causes the guide tube 15 to rotate about the working axis N.

[0040] The second drive unit 13 is connected to the impact device 9 via a second transmission device 14 in such a way that the torque generated in the first drive unit 11 is transmitted to the excitation piston 17. For this purpose, the second transmission device 14 includes a pinion 19', a gear 27, an eccentric member 28, and a connecting rod 29. The connecting rod 29 may also be referred to as a connecting rod, push rod, or main rod.

[0041] The pinion 19' is fixed to the end 20' of the rotor of the second drive unit 13, which protrudes from the stator of the second drive unit 13, so that they rotate together. The positioning of the gear 27 of the second transmission device 14 relative to the pinion 19' is such that the gear 27 is driven by the pinion 19'. Furthermore, the arrangement of the eccentric member 28 relative to the gear 27 is such that the gear 27 drives the eccentric member 28. The connecting rod 29 connects the excitation piston 17 to the eccentric member 28, so that the movement of the eccentric member 28 is transmitted to the excitation piston 17. The excitation piston 17 moves along the guide tube 15 in the direction of arrow A or B via the eccentric member 28. By means of the movement of the excitation piston 17 in the guide tube 15, the anvil 16 is driven by a pneumatic spring present between the excitation piston 17 and the anvil 16. Furthermore, the anvil 16 transmits the impact pulse to the tool assembly 3 and the tool 7.

[0042] As shown in the accompanying drawings, the first drive unit 11 and the second drive unit 13 are arranged relative to each other in the housing 2 such that the first rotation axis S of the first drive unit 11 is arranged at a first angle α with the second rotation axis T of the second drive unit 13 and at a second angle β with the working axis N. According to this exemplary embodiment, the value of the first angle α is 60°, and the value of the second angle β is 20°. According to an alternative embodiment, the value of the first angle α can be between 50° and 80°, and the value of the second angle β can be between 10° and 30°.

[0043] In this exemplary embodiment, the first rotation axis S and the second rotation axis T are located in the same plane. According to an alternative exemplary embodiment, the first rotation axis S and the second rotation axis T may also be located in different planes.

[0044] List of reference numerals

[0045] 1 Power tools

[0046] 2. Shell

[0047] 2a Front end of the casing

[0048] 2b Rear end of the housing

[0049] 3. Tool assemblies

[0050] 4 Power Supply Unit

[0051] 5 First Handle

[0052] 5a Enable switch

[0053] 6 Control Unit

[0054] 7 tools

[0055] 8 second handle

[0056] 8a Connection device

[0057] 9. Impact device

[0058] 10 Rotating device

[0059] 11 First Drive Unit

[0060] 12 First transmission device

[0061] 13 Second drive unit

[0062] 14 Second transmission device

[0063] 15. Guide tube

[0064] 16 Anvils

[0065] 17 Excitation Piston

[0066] 18 gears

[0067] 19. The small gear on the rotor

[0068] 19' The small gear on the rotor

[0069] 20. End of rotor

[0070] 20' rotor end

[0071] 21 drive shafts

[0072] 21a End of drive shaft

[0073] 22 Gear Ring

[0074] 23a First Planetary Gear

[0075] 23b Second Planetary Gear

[0076] 24 Planetary Gear Carrier

[0077] 25 Transmission ball bearings

[0078] 27 Gears

[0079] 28 Eccentric parts

[0080] 29 Connecting rod

[0081] L-wire

[0082] N working axis

[0083] R Rotation direction

[0084] S First rotation axis of the first drive unit

[0085] The second rotation axis of the second drive unit

Claims

1. A power tool (1), comprising: Housing (2); tool assembly (3) for receiving and holding tool (7); impact device (9) for generating impact pulses and transmitting these impact pulses to tool (7); and rotating device (10) for generating torque and transmitting the torque to tool (7), wherein a working axis (N) is provided through the impact device (9). The first drive unit (11) and the second drive unit (13) are provided. The first drive unit has a first rotation axis (S) for driving the rotating device (10), and the second drive unit has a second rotation axis (T) for driving the impact device (9). The arrangement of the first drive unit and the second drive unit (11, 13) relative to each other in the housing (2) is such that the first rotation axis (S) of the first drive unit (11) is arranged at a first angle (α) with the second rotation axis (T) of the second drive unit (13) and at a second angle (β) with the working axis (N). The feature is that both the first angle (α) and the second angle (β) are configured as acute angles, wherein the value of the first angle (α) can be from 50° to 80°, and the value of the second angle (β) can be from 10° to 30°.

2. The power tool (1) as described in claim 1. Its features are, The first drive unit (11) includes a first transmission device (12), and the second drive unit (13) includes a second transmission device (14).

3. The power tool (1) as described in claim 1 or 2. Its features are, The power tool includes a bevel gear (18) for connecting the first drive unit (11) to the rotary device (10).

4. The power tool (1) as described in claim 1 or 2. Its features are, The power tool (1) is a hammer drill.

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