EP2855097A1

EP2855097A1 - Percussion mechanism unit

Info

Publication number: EP2855097A1
Application number: EP13721338.5A
Authority: EP
Inventors: Helge SPRENGER; Rainer Nitsche; Thomas Winkler; Thilo Henke; Christian Bertsch; Ulli Hoffmann; Achim Duesselberg
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2012-05-25
Filing date: 2013-05-06
Publication date: 2015-04-08
Anticipated expiration: 2033-05-06
Also published as: RU2014152475A; CN104334317A; EP2855097B1; WO2013174643A1

Abstract

The invention relates to a percussion mechanism unit (10a-c), in particular for a rotary and/or percussion hammer (12a; 12c), having a control unit (14a-c) which is provided to control a drive unit (16a-c) and/or a pneumatic percussion mechanism (18a-c). An operating mode sensor (20a-c), which is provided to signal at least one operating mode to the control unit (14a-c), is proposed.

Description

description

Percussion unit

State of the art

There are already percussion units, especially for drilling and / or impact hammers, with a control unit, which is intended to control a drive unit and / or a pneumatic percussion known.

Disclosure of the invention

The invention relates to a percussion unit, in particular for a drill and / or percussion hammer, with a control unit, which is intended to control a drive unit and / or a pneumatic striking mechanism.

An operating mode sensor, which is provided to signal the control unit at least one operating mode, is proposed. A "percussion unit" is to be understood in this context, in particular a unit which is provided for operating a striking mechanism

Schlagwerkinheit may in particular have a control unit. The

Schlagwerkinheit may have a drive unit and / or a gear unit, which is provided to drive the percussion. In this context, a "control unit" is to be understood as meaning, in particular, a device of the percussion mechanism unit which is provided for controlling and / or regulating, in particular, the drive unit and / or percussion mechanism, The control unit may preferably be designed as an electrical control unit, in particular as an electronic control unit. In this context, a "hammer drill and / or percussion hammer" is to be understood as meaning, in particular, a machine tool which is provided for machining a workpiece with a rotating or non-rotating tool, the tool being guided by the tool Machine tool can be acted upon with shock pulses. The machine tool is preferably designed as a hand tool machine guided by a user by hand. In this context, a "percussion mechanism" is to be understood in particular to mean a device which has at least one component which is provided for generating and / or transmitting a shock pulse, in particular an axial impact pulse, on a tool arranged in a tool holder In particular, a racket, a firing pin, a guide element, such as in particular a hammer tube and / or a piston, such as in particular a pot piston, and / or another, the skilled person appear reasonable sense component.

The racket can transmit the impact pulse directly to the tool or indirectly. Preferably, the racket can transmit the impact pulse to a firing pin, which transmits the impact pulse to the tool. The racket is preferably movably mounted in the hammer tube. The racket may preferably be moved back cyclically in a direction of impact in the direction of the firing pin and in an opposite direction of return. The piston is preferably mounted on a side facing away from the impact direction of the racket also movable in the hammer tube. The racket and the piston can define a space with the hammer tube. The piston can be cyclically moved in the direction of impact and return direction, in particular by an eccentric. The piston is preferably cyclically moved in the direction of impact and against the direction of impact with a beat frequency and / or a percussion speed. In this context, a "percussion speed" is to be understood as meaning, in particular, a speed of an eccentric which preferably moves the piston via a connecting rod The percussion speed corresponds to the beat frequency and is subsequently used equivalently The piston movement can be a pressure of one in a space between pistons and "bats", change the volume of air forming a pressure cushion and, due to the pressure fluctuations, accelerate the beater in the direction of impact and in the return direction. "Provided" should be understood in particular to be specially designed and / or specially equipped. In this context, a "mode of operation" is to be understood as meaning, in particular, a configuration of the percussion mechanism that is intended for a specific operating state. in which it is intended for impact operation. hen is. In this context, a "striking operation" is to be understood as meaning, in particular, an operating state of the percussion mechanism in which the impact mechanism preferably applies regular impact impulses.A "idling operation" is to be understood in this context to mean, in particular, an operating condition of the percussion mechanism which is prevented by failure characterized by regular impact pulses and / or in which only very weak impact pulses are exerted by the racket on the firing pin. In this context, "very weak" is to be understood in particular as meaning that an impact strength corresponds to less than 50%, preferably less than 25%, particularly preferably less than 10% of an impact strength in impact mode The device may in particular be designed to open and / or close venting and / or idling openings of the percussion mechanism in order to switch the mode of operation In particular, the idling orifices may be provided for equalizing the pressure of the space formed by the racket and the piston with the hammer tube with an environment.When the idling orifices are fully or partially opened in idle mode, one may be caused by movement of the piston on the racket out at least reduced acceleration. Impact operation can be avoided. The racket can perform little or no movements in the direction of impact and / or return direction. There are no or only very weak impact impulses. If the idle openings are closed in impact mode, the club can experience cyclic acceleration due to the cyclical movement of the piston. The racket may begin to apply impact pulses to the firing pin so that the impact mode begins. The onset of hitting mode in hitting mode may depend on operating parameters, particularly percussion speed. In particular, a beating mode in the beat mode at a high hammer speed can be omitted. A maximum percussion speed at which the percussion mode starts in percussion mode depends on various operating parameters, in particular ambient air pressure. In this context, "signaling" is to be understood as meaning in particular an information transmission, in particular electrical and / or electronic and at least partially deviating from a purely mechanical activation of an operating state Operation mode sensor may be provided in particular to signal to the control unit that a change of the operating mode of the impact mechanism has taken place. In particular, the operating mode sensor can signal that the device for switching the operating mode has switched over the striking mechanism to an operating mode. The control unit can advantageously recognize that an operating mode change has taken place. In particular, the control unit can check whether the operating state corresponds to the operating mode. The control unit may restart the percussion mechanism upon detection of the beat mode in the absence of beat operation. In particular, the control unit can reduce the percussion speed to the start of the percussion mechanism during an operating mode change from the idle mode to the striking mode. Preferably, further sensors are provided in order to signal the idling operation and / or the impact operation to the control unit. It is proposed that the operating mode sensor is provided to determine at least one position of a switching element. In this context, a "switching element" is to be understood as meaning, in particular, a component which is intended to switch an operating mode depending on its position, Preferably, the switching element is designed as an idling sleeve , which is intended, depending on their position, to open and / or close all or part of the idling openings and / or ventilation openings of the impact mechanism to an operating mode. In this context, a "position" of the changeover element is to be understood as meaning, in particular, an impact position and an idle position The impact position may, in particular, be provided for switching the impact mechanism into impact mode Preferably, a tool holder movably supported in the direction of impact can be supported directly on the switching element or via further components , the tool holder with the switching element can shift against the force of the spring element up to a stop against the impact direction. Move the tool holder in the direction of impact up to another stop and assume the idling position. The operating mode sensor can preferably determine whether the switching element has assumed the idling position, particularly preferably whether the switching element has taken the impact position. The operating mode sensor may advantageously signal to the control unit that the striking mechanism is in strike mode. Of the

Operating mode sensor can determine the position of the control sleeve indirectly or preferably directly. In this context, the term "indirectly" should in particular be understood to mean that the operating mode sensor detects the position of a part connected to the control sleeve. "Direct" in this context means, in particular, that the operating mode sensor directly detects the position of a part of the control sleeve , The operating mode sensor can determine the position of the control sleeve particularly easily and reliably. It is further proposed that the operating mode sensor has a Hall sensor. In this context, a "Hall sensor" is to be understood as meaning, in particular, a sensor known to the person skilled in the art, which is traversed by a current and intended to detect a magnetic field perpendicular to a current flow The Hall sensor is preferably mounted in such a way that in the striking position of the switching element the magnetized part of the switching element passes into a measuring range of the Hall sensor The operating mode sensor can detect the operating mode in a particularly simple and contactless manner particularly well protected against contamination.

It is further proposed that the operating mode sensor has a magnetic switch. In this context, a "magnetic switch" is to be understood as meaning, in particular, a switch which is switched by a magnetic field, in particular a reed relay known to the person skilled in the art The magnet switch is preferably mounted such that in the striking position of the switching element the magnetized part of the switching element reaches the measuring range of the Hall sensor

Magnetic switch can generate an electrical signal for signaling the operating mode switch it directly. On an electronics or other components for the evaluation and / or preparation of a sensor signal can be dispensed with. Of the

Operating mode sensor can be particularly simple. It is further proposed that the operating mode sensor has an inductive proximity sensor. In this context, an "inductive proximity sensor" is to be understood as meaning, in particular, a sensor known to the person skilled in the art, which detects an approach of a conductive material and / or metal by a change in an inductance The mode-of-operation sensor can detect an approximation of the switching element directly, a magnetization of the switching element can be dispensed With, the inductive proximity sensor is preferably arranged such that the switching element is in the striking position of the inductive proximity sensor The operation mode sensor can detect the impact mode of the striking mechanism particularly well.

It is further proposed that the operating mode sensor has a capacitive sensor. In this context, a "capacitive sensor" is to be understood as meaning, in particular, a sensor known to a person skilled in the art, which detects a change in a capacitance when approaching a material.The capacitive sensor can, in particular, detect an approximation of non-metallic and / or non-conductive materials, in particular The changeover element can be formed from a nonconductive and / or nonmetallic material, in particular from a plastic material, Preferably, the capacitive sensor is arranged such that the changeover element adjoins the capacitive sensor in the plastics material Approaching position

Operating mode sensor can detect the impact mode of the striking mechanism particularly well.

It is further proposed that the operating mode sensor has an optical sensor. In this context, an "optical sensor" is to be understood as meaning, in particular, a sensor known to a person skilled in the art, which is based on a measurement of light in or near the visible region, such as infrared and / or ultraviolet radiation. The optical sensor may preferably be a light barrier, in particular a fork light barrier. The optical sensor can detect the presence of an opaque material. The operating mode sensor can directly detect an approach of the switching element. The switching element may be formed of non-transparent material, in particular of plastic. Preferably, the optical sensor is arranged so that the switching element approaches the optical sensor in the impact position. The operation mode sensor can detect the impact mode of the striking mechanism particularly well.

It is further proposed that the operating mode sensor has a sensor for a mechanical measured variable and / or a mechanical switch. In this context, a "mechanical measured variable" is to be understood as meaning, in particular, a force and / or pressure and / or deformation and / or position The operating mode sensor may comprise a mechanical switch, in particular a microswitch known to the person skilled in the art The switching-over element can mechanically switch the switch preferably in the striking position by a force The operating-mode sensor can have a force sensor, in particular a piezoelectric sensor Preferably, the force sensor can be arranged on a stop of the switching element The switching element can form a switch with the stop The stop can have a switching contact which closes a circuit with the switching element as soon as the switching element is supported on the stop.

The operation mode sensor can detect the position of the switching element in a particularly simple and direct manner. The mode of operation sensor may include a potentiometer. In particular, the operating mode sensor with the control sleeve can form a potentiometer. The potentiometer can change its resistance depending on a position of the control sleeve. The operation mode sensor may be the

Detect the position of the control sleeve continuously. The operation mode sensor may detect intermediate positions between the impact position and an idle position.

It is further proposed that the operating mode sensor is provided to determine a contact pressure. Under a "contact pressure" should in this Zu- In particular, a force can be understood with which a tool arranged in the tool holder of the power tool is pressed against a workpiece. The contact pressure can trigger the operating mode change, in particular when a threshold value is exceeded. In particular, the contact pressure can switch the impact mechanism from the idle mode to the beat mode. The threshold value can be determined in particular by the spring element which exerts a force in the direction of impact on the switching element. The operating mode sensor can be provided to measure the contact pressure in the force flow of the spring element and / or of the switching element, in particular with a piezoelectric sensor. The operating mode sensor can advantageously detect the operating mode by comparing the contact pressure with the threshold value. The threshold value can be advantageously adjustable.

It is further proposed that the operating mode sensor is provided to determine a pressing force of at least one handle. In this context, a "pressure force" is to be understood as meaning, in particular, a force component in the direction of impact in the handle, with which the user presses the hand tool machine against the workpiece The operating mode sensor preferably determines the pressure force in the handle and a further pressure force in an additional handle The pressure forces can be components of the contact pressure The pressure can be estimated from the pressure forces A measurement of the pressure force in the handle can be particularly simple In particular, the operating mode sensor can measure a deformation of a spring and / or damping element of the handle with a sensor known to the person skilled in the art as a strain gauge sensor, a measurement of the contact pressure can be dispensed with.

It is further proposed that the operating mode sensor is provided to take into account a signal of a position sensor. In this context, a "position sensor" should be understood as meaning, in particular, a sensor which is intended to measure the direction of a weight force. A weight of the handheld power tool can be taken into account when determining the contact pressure. Further, a hand tool with a percussion unit is proposed with the properties described. The hand tool may have the described properties.

drawing

Further advantages emerge from the following description of the drawing. In the drawing, three embodiments of the invention are shown. The drawing, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

Show it:

1 is a schematic representation of a hammer and percussion hammer with a percussion unit with an operating mode sensor,

Fig. 2 is a schematic representation of a hammer and percussion hammer with a percussion unit with an operating mode sensor in a second embodiment and

Fig. 3 is a schematic representation of a drilling and percussion hammer with a percussion unit with a mode of operation sensor in a third embodiment.

Description of the embodiments

FIG. 1 shows a drilling and percussion hammer 12a with a striking mechanism unit 10a. The impact mechanism unit 10a comprises a control unit 14a which is provided to control a drive unit 16a of a pneumatic percussion mechanism 18a.

The drive unit 16a includes a motor 46a with a gear unit 48a which, depending on a switching position for a drilling operation, rotatably drives a hammer tube 50a and / or for an impact mode an eccentric 52a. The hammer tube 50a is rotatably connected to a tool holder 54a, in which a tool 56a can be clamped. The tool holder 54a and the tool 56a may be driven for a drilling operation via the hammer tube 50a with a rotating working movement 58a. When a beater 60a for impact operation in a direction of impact 62a becomes toward the tool holder 54a accelerates, it exerts a shock pulse in an impact on a between the racket 60a and the tool 56a arranged firing pin 64a, which is passed from the firing pin 64a to the tool 56a. The tool 56a exerts a striking working movement 66a by the impact pulse. A piston 68a is also movably mounted in the hammer tube 50a on the side of the racket 60a facing away from the direction of impact 62a. The piston 68a is periodically moved in the hammer tube 50a in the striking direction 62a and back again by means of a connecting rod 70a from the striking gear speed driven eccentric 52a. The piston 68a compresses in a striking mode a pressure pad 78a enclosed in a space 76a between the piston 68a and the beater 60a in the hammer tube 50a. Upon movement of the piston 68a in the direction of impact 62a, the beater 60a is accelerated in the direction of impact 62a. The impact mode can start. By a rebound on the firing pin 64a and / or by a return movement of the piston 68a against the direction of impact 62a between the piston 68a and the racket

60a and / or by a counter-pressure in a space 80a between the racket 60a and the firing pin 64a, the racket 60a can be moved back against the direction of impact 62a and then accelerated again in the direction of impact 62a for a next impact pulse. Whether the working movement 66a takes place in the beat mode depends on operating parameters, in particular a percussion speed. In a region between the beater 60a and the striker 64a, breather ports 82a are disposed in the hammer tube 50a so that the air trapped between the beater 60a and the striker 64a can escape. In a region between the beater 60a and the piston 68a are in

Hammer tube 50a idle openings 84a arranged. The tool holder 54a is slidably mounted in the direction of impact 62a and is supported via the firing pin 64a and a control disk 100a on a switching element 22a designed as an idle sleeve. A spring element 86a exerts a force in the direction of impact 62a on the switching element 22a. In a beat mode in which the

Tool 56a is pressed by the user against a workpiece, the tool holder 54a moves against the force of the spring member 86a, the switching element 22a in an impact position so that it covers the idling openings 84a. When the tool 56a is set down from the workpiece, the tool holder 54a and the switching element 22a are thus impacted by the spring element 86a. direction 62a shifted into an idling mode that the switching element 22a in an idle position, the idling openings 84a releases. A pressure in the pressure pad 78a between the piston 68a and the beater 60a may escape through the idle ports 84a. The racket 60a is not accelerated in idle mode or only slightly accelerated by the pressure pad 78a. In idle mode, the racket 60a exerts no or only small impact pulses on the firing pin 64a. The hammer 12a has a hand tool housing 92a with a handle 40a on which it is guided by a user.

An operation mode sensor 20a is provided to detect a position of the switching element 22a relative to the hammer tube 50a. In particular, the operation mode sensor 20a is provided for determining whether the switching element 22a is in the striking position. The operation mode sensor 20a signals the control unit 14a the beat mode. The operation mode sensor 20a includes a signal processing unit 96a disposed on the control unit 14a. The operation mode sensor 20a has an inductive proximity sensor 28a connected to the signal processing unit 96a, which is connected to the signal processing unit 96a via a signal connection (not shown). The proximity sensor 28a is disposed in an idling position of the switching element 22a opposite to the control disk 100a. When the control disk 100a and the switching element 22a are moved to the stroke position, the control disk 100a moves away from the proximity sensor 28a. Of the

Operating mode sensor 20a signals the beat mode when the switching element 22a is in the strike position and the control disk

100a away from the proximity sensor 28a. Alternatively, an assembly of the proximity sensor 28a is conceivable in which the control disk 100a approximates the proximity sensor 28a in impact position, so that the operating mode sensor 20a signals the impact mode when approaching the control disk 100a to the proximity sensor 28a. Alternatively, the proximity sensor 28a may be arranged to detect an approach of the switching element 22a itself rather than an approach of the control disk 100a.

The operation mode sensor 20a is further provided to detect a pressing force 38a of the handle 40a. By determining the pressing force 38a is the operating mode sensor 20a, a further parameter for detecting the operating mode available. The operation mode sensor 20a may evaluate the pressing force 38a instead of the position of the switching element 22a or in addition to the position of the switching element 22a. The operation mode sensor 20a has a potentiometer 106a connected to the signal processing unit 96a, which is connected to a pivot 104a of the handle 40a. The handle 40a rotates with increasing pressure force 38a about the pivot 104a. An electrical resistance of the potentiometer 106a is dependent on the pressing force 38a of the handle 40a. If an adjustable threshold value is exceeded, the operating mode sensor 20a signals the beat mode.

The operating mode sensor 20a also has a position sensor 42a. The position sensor 42 a is used to measure the direction of a weight force. Of the

Operation mode sensor 20a takes into account the weight force in setting the threshold values of the pressing force 38a to signal the beat mode.

By a vector addition of the pressure force 38a and the weight force, a contact pressure 36a can be determined, which causes the switch to the impact mode.

The following description and the drawings of further exemplary embodiment are essentially limited to the differences between the exemplary embodiments, reference being made in principle to the drawings and / or the description of the other exemplary embodiments with respect to identically named components, in particular with regard to components having the same reference numbers can be. To distinguish the embodiments, instead of the letter a of the first embodiment, the letters b and c are the

Reference numerals of further embodiments nachgestellt.

Figure 2 shows a schematic representation of a hammer and percussion hammer 12b with a percussion unit 10b with a mode of operation sensor 20b with a control unit 14b, a drive unit 16b and a pneumatic hammer mechanism 18b in a second embodiment. The percussion unit

10b differs from the first embodiment in particular in that the operating mode sensor 20b has a switch 32b connected to a signal processing unit 96b. The switch 32b is designed as a microswitch guided and signals a beat position of a switching element 22b. The switch 32b is disposed in an idling position of the switching element 22b opposite to the control disk 100b, so that a control disk 100b operates the switch 32b. When the control disk 100b and the switching element 22b are moved to the stroke position, the control disk 100b moves away from the

Switch 32b, so that this opens. The operation mode sensor 20b signals the impact mode when the switching element 22b is in the impact position and the control disk 100b moves away from and opens the switch 32b. Alternatively, an assembly of the switch 32b is conceivable in which the control disk 100b approaches the switch 32b in impact position, so that the operating mode sensor 20b signals the impact mode when the control disk 100b actuates the switch 32b. Alternatively, the switch 32b may be arranged to be operated by the switching element 22b instead of the control disk 100b.

Figure 3 shows a schematic representation of a hammer and percussion hammer 12c with a percussion unit 10c with a mode of operation sensor 20c, with a control unit 14c, a drive unit 16c and a pneumatic hammer mechanism 18c in a third embodiment. The impact mechanism unit 10c differs from the first embodiment in particular in that the

Operating mode sensor 20c has a connected to a signal processing unit 96c Hall sensor 24c. The Hall sensor 24c detects a non-contact magnetic area 98c of a control disk 100c and signals a striking position of a switching element 22c. The Hall sensor 24 c is disposed in an idle position of the switching element 22 c with respect to the control disk 100 c, so that the Hall sensor 24 c detects the magnetic region 98 c. When the control disk 100c and the switching element 22c are moved to the stroke position, the control disk 100c moves away from the Hall sensor 24c. Of the

Operation mode sensor 20c signals the beat mode when the switching element 22c is in the beat position and the control disk

100c away from the Hall sensor 24c. Alternatively, an assembly of the Hall sensor 24c is conceivable in which the control disk 100c approaches the Hall sensor 24c in impact position, so that the operating mode sensor 20c signals the impact mode when the control disk 100c has approached the Hall sensor 24c. Alternatively, the Hall sensor 24c may be arranged to be detects an approach of a magnetic portion of the switching element 22c instead of the magnetic portion 98c of the control disk 100c.

Claims

claims

Impact unit, in particular for a drilling and / or percussion hammer (12a, 12c), with a control unit (14a-c), which is intended to drive unit (16a-c) and / or a pneumatic percussion (18a-c) to be controlled, characterized by an operating mode sensor (20a-c) which is provided to signal the control unit (14a-c) at least one operating mode.

Impact unit according to claim 1, characterized in that the

Operating mode sensor (20a-c) is provided to determine at least one position of a switching element (22a-c).

Impact unit according to one of the preceding claims, characterized in that the operating mode sensor (20c) has a Hall sensor (24c).

Impact unit according to one of the preceding claims, characterized in that the operating mode sensor (20a) has an inductive proximity sensor (28a).

Impact unit according to one of the preceding claims, characterized in that the operating mode sensor (20b) has a sensor for a mechanical measured variable and / or a mechanical switch (32b).

Impact unit according to one of the preceding claims, characterized in that the operating mode sensor (20a) is provided to determine a contact pressure (36a). Impact unit at least according to claim 6, characterized in that the operating mode sensor (20a) is provided to determine a pressure force (38a) at least one handle (40a) and / or an additional handle.

Impact unit according to one of the preceding claims, characterized in that the operating mode sensor (20a) is provided to take into account a signal of a position sensor (42a). 9. Hand tool with a percussion unit according to one of the preceding claims.