CN209507003U

CN209507003U - The fragment transferring device of punching

Info

Publication number: CN209507003U
Application number: CN201822155750.2U
Authority: CN
Inventors: 伍森荣; 周毅; 胡长瑞
Original assignee: Guangdong Parfu Electric Machinery Co Ltd
Current assignee: Guangdong Parfu Electric Machinery Co Ltd
Priority date: 2018-12-21
Filing date: 2018-12-21
Publication date: 2019-10-18
Anticipated expiration: 2028-12-21

Abstract

The utility model relates to a kind of fragment transferring devices of punching, comprising: rack, control module, push component, feeding assembly and rotor component, the push component are used to punching being pushed into the rotor component；The feeding assembly is used for push component punching without interruption；The rotor component includes sleeve, shaft and the second driver, the sleeve is mounted on the rack, and it is located at side of the described sleeve pipe far from the pushing block, second driver and the control module are electrically connected, one end of the shaft is connect with the output end of second driver, the other end of the shaft is equipped with the pallet being placed in the sleeve, the pallet is for punching described in support, the pallet is equipped with the switch portion for driving the punching rotation, the axis of the shaft is overlapped with the axis of the sleeve, the fragment transferring device of above-mentioned punching can effectively improve production efficiency, it can guarantee punching overlapping precision with higher simultaneously.

Description

The fragment transferring device of punching

Technical field

The utility model relates to motor manufacturing equipment technical fields, more particularly to a kind of fragment transferring device of punching.

Background technique

In the punching processing of motor, punching is first usually subjected to fragment, later overlaps several punchings to certain thickness, Rotor processing is carried out to punching again, it is to eliminate the accumulated error after punching overlapping, i.e., poor with plate, but the current above process is by people Hand operation, causes production efficiency lower, while not can guarantee the overlapping precision of punching.

Utility model content

Based on this, it is necessary in view of the above technical problems, provide a kind of fragment transferring device of punching, it can be effectively improved Production efficiency, while can guarantee punching overlapping precision with higher.

To achieve the above object, the utility model provides a kind of fragment transferring device of punching, the fragment of the punching Transferring device includes: rack, control module, push component, feeding assembly and rotor component, the control module, the charging Component, the push component and the rotor component are set in the rack；The push component includes pushing block, bottom plate and One driver, the bottom plate are mounted on the rack, and the pushing block and first driver are installed on the bottom plate, For driving the pushing block to move in a straight line, first driver electrically connects first driver with the control module It connects；The feeding assembly includes casing, and for described sleeve pipe for accommodating punching, described sleeve pipe is mounted on the rack along the vertical direction Top that is upper and being located at the bottom plate, between described sleeve pipe has along longitudinal direction between one end and the bottom plate of the rack Gap, the height in the gap are greater than the height of the punching, and the pushing block enters the gap and successively releases the punching；Institute Stating rotor component includes sleeve, shaft and the second driver, and the sleeve is mounted on the rack, and it is remote to be located at described sleeve pipe Side from the pushing block, second driver and the control module are electrically connected, one end of the shaft and described the The output end of two drivers connects, and the other end of the shaft is equipped with the pallet being placed in the sleeve, and the pallet is used for Punching described in support, the pallet are equipped with the switch portion for driving punching rotation, the axis of the shaft with it is described The axis of sleeve is overlapped.

The fragment transferring device of above-mentioned punching compared with the background art, at least has the advantages that when in use, first Several punchings are successively overlayed in casing, the punching positioned at least significant end is fallen in gap, then, control module control first Driver starting, the first driver drive pushing block to release, and the punching in gap is pushed away to dropping down onto sleeve and by tray supporting, is connect , control module controls the starting of the second driver, and the second driver drive shaft rotates by a certain angle, meanwhile, pass through switch portion It drives punching to rotate jointly, continues to repeat aforesaid operations to next punching dropped down onto gap later, until the punching in sleeve Overlapping completes the fragment rotor process of the punching of a rotor to setting thickness.In this way, above process automatic operation, The production efficiency of motor is effectively increased, meanwhile, control module is by the second driver of control, to realize each rotor operation Rotation angle is accurately controlled, to can ensure that punching overlapping precision with higher, to eliminate the same plate after punching overlapping Difference.

In one embodiment, the push component further includes two guide pads being fixedly mounted on the bottom plate, Guide groove is formed between two guide pads, the pushing block is moved in a straight line along the guide groove.

In one embodiment, the feeding assembly further includes seat board, and the seat board is erected on two guide pads, Described sleeve pipe is fixedly mounted on the seat board, and it is logical that corresponding with the pore of described sleeve pipe first is opened up in the middle part of the seat board Hole.

In one embodiment, the push component further includes the first locating part and the second locating part, first limit Position part is set to the feeding assembly close to the side of the pushing block, and second locating part is equipped with first driver close to institute The side of pushing block is stated, first locating part and second locating part limit the linear motion range of the pushing block jointly.

In one embodiment, the rotor component further includes position detection unit, and the position detection unit includes Position sensor and position needle, the shaft are equipped with the first jack with the axis vertical take-off of the shaft, and the position needle is inserted It connects in first jack, the position needle is for triggering the position sensor, the position sensor and the control Module is electrically connected.

In one embodiment, the fragment transferring device of the punching further includes discharge component, the discharge component packet Thimble and third driver are included, the middle part of the shaft is equipped with along axial slot, and the opposite sides of the shaft, which is equipped with, to be used for The guide hole that the slot is in communication with the outside, the guide hole are arranged along the axis of the shaft, and the thimble is plugged on the slot In hole, the axis of the thimble is overlapped with the axis of the sleeve, the output end of the third driver by the guide hole with The thimble connection, the third driver is for driving the thimble to move up and down along the guide hole, the third driver It is electrically connected with the control module.

In one embodiment, the thimble is close to one end of the third driver equipped with second in the horizontal direction Jack is plugged with card needle in second jack, and the card needle is also cross two guide holes, the output of the third driver It is connected with snap-gauge on end, the second through-hole passed through for the shaft is opened up on the snap-gauge, the snap-gauge is resisted against the card needle Bottom.

In one embodiment, the discharge component further includes spring, and the spring is socketed in the shaft, described One end of spring is pressed on the bottom of the pallet, and the other end of the spring is pressed on the top of the card needle.

In one embodiment, the fragment transferring device of the punching further includes pushing component, the pushing component packet Fourth drive, the 5th driver and pressure head are included, the fourth drive is mounted on the rack, the 5th driving installation On the output end of the fourth drive, the pressure head is mounted on the output end of the 5th driver, the 4 wheel driven The top that dynamic device is used to that the pressure head to be driven to be moved to the sleeve in the horizontal direction, the 5th driver are described for driving Pressure head moves up and down, and the punching in the sleeve is pushed, the fourth drive and the 5th driver with The control module is electrically connected.

In one embodiment, the fragment transferring device of the punching further includes display, and the display is set to institute It states in rack, the display and the control module are electrically connected.

Detailed description of the invention

Fig. 1 is the structural schematic diagram of the fragment transferring device of punching described in an embodiment of the present invention；

Fig. 2 is the structural schematic diagram of the push component in the fragment transferring device of punching shown in Fig. 1；

Fig. 3 is the structural schematic diagram of the rotor component in the fragment transferring device of punching shown in Fig. 1；

Fig. 4 is the part partition structural schematic diagram of the fragment transferring device of punching shown in Fig. 1；

Fig. 5 is the structural schematic diagram of the pushing component in the fragment transferring device of punching shown in Fig. 1.

10, rack, 11, electric box, 20, push component, 21, bottom plate, 22, pushing block, the 23, first driver, 24, guiding Block, the 25, second locating part, 30, feeding assembly, 31, casing, 32, seat board, 40, rotor component, 41, sleeve, 42, shaft, 421, Pallet, 422, switch portion, 423, position needle, 424, slot, 425, guide hole, the 43, second driver, 50, discharge component, 51, top Needle, 511, card needle, 52, third driver, 53, snap-gauge, 54, spring, 60, pushing component, 61, fourth drive, the 62, the 5th drives Dynamic device, 63, pressure head, 70, display.

Specific embodiment

The utility model is more fully retouched below with reference to relevant drawings for the ease of understanding the utility model, It states.The better embodiment of the utility model is given in attached drawing.But the utility model can come in many different forms It realizes, however it is not limited to embodiments described herein.On the contrary, the purpose of providing these embodiments is that making practical new to this The disclosure of type understands more thorough and comprehensive.

It should be noted that it can directly on the other element when element is referred to as " being fixed on " another element Or there may also be elements placed in the middle.When an element is considered as " connection " another element, it, which can be, is directly connected to To another element or it may be simultaneously present centering elements.On the contrary, when element is referred to as " directly existing " another element "upper", There is no intermediary elements.Term as used herein " vertical ", " horizontal " and similar statement simply to illustrate that Purpose." first " described in the utility model, " second ", " third ", " the 4th ", " the 5th " do not represent specific quantity and suitable Sequence is only used for the differentiation of title.

As shown in Figure 1 to Figure 3, the fragment transferring device of a kind of punching, comprising: rack 10, control module are (in attached drawing not Show), push component 20, feeding assembly 30 and rotor component 40.Control module, feeding assembly 30, push component 20 and rotor Component 40 is set in rack 10；Push component 20 includes that bottom plate 21, pushing block 22 and the first driver 23, bottom plate 21 are mounted on machine On frame 10, pushing block 22 and the first driver 23 are installed on bottom plate 21, and the first driver 23 is for driving pushing block 22 to do straight line Movement, the first driver 23 are electrically connected with control module；Feeding assembly 30 includes casing 31, and casing 31 is used to accommodate punching, Casing 31 is mounted on the top in rack 10 and being located at bottom plate 21, the one end and bottom plate of casing 31 close to rack 10 along the vertical direction There is gap along longitudinal direction, the height in gap is greater than the height of punching, and pushing block 22 successively releases punching into gap between 21； Rotor component 40 includes that sleeve 41, shaft 42 and the second driver 43, sleeve 41 are mounted in rack 10, and it is remote to be located at casing 31 Side from pushing block 22, the second driver 43 are electrically connected with control module, and one end of shaft 42 is defeated with the second driver 43 Outlet connection, the other end of shaft 42 are equipped with the pallet 421 being placed in sleeve 41, and pallet 421 is used for support punching, pallet 421 are equipped with the switch portion 422 for driving punching to rotate, and the axis of shaft 42 is overlapped with the axis of sleeve 41.

The fragment transferring device of above-mentioned punching when in use, first successively overlays several punchings in casing 31, is located at most The punching of low side is fallen in gap, and then, control module controls the starting of the first driver 23, and the first driver 23 drives pushing block 22 release, and the punching in gap is pushed away and drops down onto sleeve 41 and is supported by pallet 421, then, the second driving of control module control Device 43 starts, and 43 drive shaft 42 of the second driver rotates by a certain angle, meanwhile, drive punching to revolve jointly by switch portion 422 Turn, continue to repeat aforesaid operations to next punching dropped down onto gap later, until the punching in sleeve 41 is overlapped to setting thickness Degree, that is, complete the fragment rotor process of the punching of a rotor.In this way, above process automatic operation, effectively increases electricity The production efficiency of machine, meanwhile, control module by the second driver 43 of control, with realize the rotation angle of each rotor operation by To accurately controlling, thus can ensure that punching overlapping precision with higher, it is poor to eliminate the same plate after punching overlapping.

Further, the fragment transferring device of punching further includes electric box 11, and control module is set in electric box 11.

Preferably, the first driver 23 is electric cylinder, and the air-leg of electric cylinder is connect with pushing block 22.Certainly, first Driver 23 can also be other electrically-actuated devices, such as motor, motor can be connect by transmission mechanism with pushing block 22 with realize drive Pushing block 22 moves in a straight line, and transmission mechanism can have for screw body, gear and rack teeth mechanism etc. switchs to straight line fortune for rotary motion Dynamic mechanism.

Preferably, the second driver 43 is servo motor, and certainly, the second driver 43 can also be other motor types, such as Stepper motor.Fig. 3 is referred to, the second driver 43 is matched with shaft 42 by belt (not showing that in attached drawing) and gear in figure It closes and realizes connection, but the second driver 43 and the connection type of shaft 42 are not limited to that, as can also be by shaft coupling by the The output end of two drivers 43 is connect with shaft 42.

Preferably, pallet 421 uses cross-shaped structure, and switch portion 422 is set in any end of pallet 421, wherein is dialled Transfer part 422 can be driving lever.

Referring to figure 2., in one embodiment, push component 20 further includes two guide pads being fixedly mounted on bottom plate 21 24, guide groove (not identifying in attached drawing) is formed between two guide pads 24, pushing block 22 is moved in a straight line along guide groove.It is led by setting Slot moves in a straight line pushing block 22 along the guiding of guide groove, improves the moving stability of pushing block 22.

Referring to Figure 1, in one embodiment, feeding assembly 30 further includes seat board 32, and seat board 32 is erected at two guide pads 24 On, casing 31 is fixedly mounted on seat board 32, and the middle part of seat board 32 opens up first through hole (attached drawing corresponding with the pore of casing 31 In do not show that).Punching is fallen from casing 31 and is dropped down onto guide groove through first through hole, is then released by pushing block 22.

Fig. 2 is referred to, in one embodiment, push component 20 further includes the first locating part (not showing that in attached drawing) and the Two locating parts 25, the first locating part are set to feeding assembly 30 close to the side of pushing block 22, and the second locating part 25 is equipped with the first driving Device 23 is close to the side of pushing block 22, the linear motion range of the first locating part and the common limitation pushing block 22 of the second locating part 25.

Fig. 3 is referred to, in one embodiment, rotor component 40 further includes position detection unit, and position detection unit includes Position sensor (not showing that in attached drawing) and position needle 423, shaft 42 is equipped with inserts with the first of the axis vertical take-off of shaft 42 Hole (does not identify) in attached drawing, and position needle 423 is plugged in the first jack, and position needle 423 is used for trigger position sensor, position Sensor and control module are electrically connected.Since the second driver 43 is usually connect by transmission mechanism with shaft 42, second 43 drive shaft 42 of driver is easy to appear error when rotating.Above-mentioned position detection unit is used to detect 42 rotational case of shaft, Ensure that each swing circle of shaft 42 is all 360 °, specifically, follows shaft 42 to rotate by position needle 423, position needle 423 is every It is primary to be rotated by 360 ° rear trigger position sensor, position sensor controls trigger signal feedback to control module, control module Second driver 43 stops.Above-mentioned setting effectively improves the rotor precision of rotor component 40, further increases the overlapping essence of punching Degree, it is poor to eliminate the same plate after punching overlapping.

Referring to Figure 1 and Fig. 4, in one embodiment, the fragment transferring device of punching further includes discharge component 50, discharging group Part 50 includes thimble 51 and third driver 52, and the middle part of shaft 42 is equipped with along axial slot 424, the opposite sides of shaft 42 Equipped with the guide hole 425 for slot 424 to be in communication with the outside, guide hole 425 is arranged along the axis of shaft 42, and thimble 51 is plugged on slot In hole 424, the axis of thimble 51 is overlapped with the axis of sleeve 41, and the output end of third driver 52 passes through guide hole 425 and thimble 51 connections, for third driver 52 for driving thimble 51 to move up and down along guide hole 425, third driver 52 and control module are electrical Connection.When the overlapping thickness of punching reaches setting value, control module controls third driver 52 and starts, and thimble 51 drives in third It is ejected from sleeve 41 to moving up to stacking punching under the driving effect of dynamic device 52 along guide hole 425, later by manually will Punching, which stacks, removes, and later, control module is resetted in control third driver 52.Discharge component 50 can realize discharging automation, Further improve the working efficiency of the fragment transferring device of punching.

Preferably, third driver 52 is electric cylinder, and the air-leg of electric cylinder is connected by guide hole 425 and thimble 51 It connects.Certainly, third driver 52 can also be other electrically-actuated devices, and such as motor, motor can pass through transmission mechanism and pushing block 22 connects It connects to realize that driving pushing block 22 moves in a straight line, transmission mechanism can have for screw body, gear and rack teeth mechanism etc. and will rotate fortune Turn is the mechanism of linear motion.

Continuing with referring to Fig. 1 and Fig. 4, specifically, thimble 51 is equipped in the horizontal direction close to one end of third driver 52 The second jack (in attached drawing not identify), be plugged with card needle 511 in the second jack, card needle 511 also cross two guide holes 425, It is connected with snap-gauge 53 on the output end of third driver 52, the second through-hole passed through for shaft 42 is opened up on snap-gauge 53 (in attached drawing Do not identify), snap-gauge 53 is resisted against the bottom of card needle 511.When third driver 52 starts, third driver 52 is by snap-gauge 53 It jacks up, while punching is stacked upward jack-up so that thimble 51 be driven to move up by the upward pushing tow card needle 511 of snap-gauge 53.

Continuing with referring to Fig. 1 and Fig. 4, further, discharge component 50 further includes spring 54, and spring 54 is socketed in shaft 42 On, one end of spring 54 is pressed on the bottom of pallet 421, and the other end of spring 54 is pressed on the top of card needle 511.In thimble 51 Under pushing tow state, spring 54 is compressed between pallet 421 and card needle 511, controls third driver 52 in control module While reset, the elastic force of spring 54 acts on card needle 511, to accelerate the falling speed of thimble 51, realizes the fast of thimble 51 Reply immediately position.

Referring to Figure 1 and Fig. 5, in one embodiment, the fragment transferring device of punching further includes pushing component 60, pushing group Part 60 includes fourth drive 61, the 5th driver 62 and pressure head 63, and fourth drive 61 is mounted in rack 10, the 5th driving It is mounted on the output end of fourth drive 61, pressure head 63 is mounted on the output end of the 5th driver 62, fourth drive 61 It is moved to the top of sleeve 41 in the horizontal direction for drive ram 63, the 5th driver 62 in drive ram 63 for moving down It is dynamic, the punching in sleeve 41 is pushed, fourth drive 61 and the 5th driver 62 are electrically connected with control module.It is rushing After piece is released by pushing block 22, punching free-falling is into sleeve 41, during punching free-falling, inevitably will receive various outer Power influences, cause punching cannot level overlay in sleeve 41, and then rotor is caused to fail.Above-mentioned pushing component 60 can be in punching After falling to sleeve 41, control module controls fourth drive 61 and starts, and pressure head 63 is made to move to the surface of sleeve 41, then controls Molding block controls the starting of the 5th driver 62, and drive ram 63 moves down, and the punching in sleeve 41 is pushed, control module exists later The starting of the second driver 43 is controlled, rotor operation is carried out, after completing rotor operation, it is multiple that control module control pushes component 60 Position.Above-mentioned pushing component 60 can ensure that punching energy level overlays in sleeve 41, effectively improve the fragment transferring device of punching Functional reliability.

Preferably, fourth drive 61 is electric cylinder, and the air-leg of electric cylinder is connect with pushing block 22.Certainly, the 4th Driver 61 can also be other electrically-actuated devices, such as motor, motor can be connect by transmission mechanism with pushing block 22 with realize drive Pushing block 22 moves in a straight line, and transmission mechanism can have for screw body, gear and rack teeth mechanism etc. switchs to straight line fortune for rotary motion Dynamic mechanism.

Preferably, the 5th driver 62 is electric cylinder, and the air-leg of electric cylinder is connect with pushing block 22.Certainly, the 5th Driver 62 can also be other electrically-actuated devices, such as motor, motor can be connect by transmission mechanism with pushing block 22 with realize drive Pushing block 22 moves in a straight line, and transmission mechanism can have for screw body, gear and rack teeth mechanism etc. switchs to straight line fortune for rotary motion Dynamic mechanism.

Referring to Figure 1, in one embodiment, the fragment transferring device of punching further includes display 70, and display 70 is set to In rack 10, display 70 and control module are electrically connected.It is various that aforementioned display device 70 can allow operator more intuitively to check Control parameter effectively improves the operation convenience of the fragment transferring device of punching.

Each technical characteristic of embodiment described above can be combined arbitrarily, for simplicity of description, not to above-mentioned reality It applies all possible combination of each technical characteristic in example to be all described, as long as however, the combination of these technical characteristics is not deposited In contradiction, all should be considered as described in this specification.

Above-described embodiments merely represent several embodiments of the utility model, the description thereof is more specific and detailed, But it cannot be understood as the limitations to utility model patent range.It should be pointed out that for the common skill of this field For art personnel, without departing from the concept of the premise utility, various modifications and improvements can be made, these are belonged to The protection scope of the utility model.Therefore, the scope of protection shall be subject to the appended claims for the utility model patent.

Claims

1. a kind of fragment transferring device of punching, which is characterized in that the fragment transferring device of the punching includes: rack, control Molding block, push component, feeding assembly and rotor component, the control module, the feeding assembly, the push component and institute Rotor component is stated to be set in the rack；The push component includes pushing block, bottom plate and the first driver, the bottom plate installation In the rack, the pushing block and first driver are installed on the bottom plate, and first driver is for driving It moves the pushing block to move in a straight line, first driver and the control module are electrically connected；The feeding assembly includes set Pipe, described sleeve pipe are mounted on the rack along the vertical direction for accommodating punching, described sleeve pipe and are located at the upper of the bottom plate Side, described sleeve pipe have gap along longitudinal direction between one end and the bottom plate of the rack, and the height in the gap is big In the height of the punching, the pushing block enters the gap and successively releases the punching；The rotor component include sleeve, Shaft and the second driver, the sleeve are mounted on the rack, and are located at side of the described sleeve pipe far from the pushing block, institute It states the second driver and the control module is electrically connected, the output end of one end of the shaft and second driver connects It connects, the other end of the shaft is equipped with the pallet being placed in the sleeve, and the pallet is for punching described in support, the support Disk is equipped with the switch portion for driving the punching rotation, and the axis of the shaft is overlapped with the axis of the sleeve.

2. the fragment transferring device of punching according to claim 1, which is characterized in that the push component further includes two The guide pad being fixedly mounted on the bottom plate forms guide groove between two guide pads, and the pushing block is done directly along the guide groove Line movement.

3. the fragment transferring device of punching according to claim 2, which is characterized in that the feeding assembly further includes seat Plate, the seat board are erected on two guide pads, and described sleeve pipe is fixedly mounted on the seat board, is opened in the middle part of the seat board If first through hole corresponding with the pore of described sleeve pipe.

4. the fragment transferring device of punching according to claim 1, which is characterized in that the push component further includes first Locating part and the second locating part, first locating part are set to the feeding assembly close to the side of the pushing block, and described second Locating part is equipped with first driver close to the side of the pushing block, and first locating part and second locating part are common Limit the linear motion range of the pushing block.

5. the fragment transferring device of punching according to claim 1, which is characterized in that the rotor component further includes position Detection unit, the position detection unit include position sensor and position needle, and the shaft is equipped with the axis with the shaft The first orthogonal jack of line, the position needle are plugged in first jack, and the position needle is passed for triggering the position Sensor, the position sensor and the control module are electrically connected.

6. the fragment transferring device of punching according to claim 1, which is characterized in that the fragment transferring device of the punching It further include discharge component, the discharge component includes thimble and third driver, and the middle part of the shaft is equipped with along axial slot Hole, the opposite sides of the shaft are equipped with the guide hole for the slot to be in communication with the outside, and the guide hole is along the shaft Axis setting, the thimble are plugged in the slot, and the axis of the thimble is overlapped with the axis of the sleeve, the third The output end of driver is connect by the guide hole with the thimble, and the third driver is for driving the thimble described in Guide hole moves up and down, and the third driver and the control module are electrically connected.

7. the fragment transferring device of punching according to claim 6, which is characterized in that the thimble drives close to the third One end of dynamic device is equipped with the second jack in the horizontal direction, is plugged with card needle in second jack, the card needle also cross Two guide holes are connected with snap-gauge on the output end of the third driver, open up on the snap-gauge and pass through for the shaft Second through-hole, the snap-gauge are resisted against the bottom of the card needle.

8. the fragment transferring device of punching according to claim 7, which is characterized in that the discharge component further includes bullet Spring, the spring are socketed in the shaft, and one end of the spring is pressed on the bottom of the pallet, the spring it is another End is pressed on the top of the card needle.

9. the fragment transferring device of punching according to claim 1-8, which is characterized in that the fragment of the punching Transferring device further includes pushing component, and the pushing component includes fourth drive, the 5th driver and pressure head, the 4 wheel driven Dynamic device is mounted on the rack, and the 5th driving is mounted on the output end of the fourth drive, the pressure head installation On the output end of the 5th driver, the fourth drive is described for driving the pressure head to be moved in the horizontal direction The top of sleeve, the 5th driver, will be under the punchings in the sleeve for driving the pressure head to move up and down Pressure, the fourth drive and the 5th driver are electrically connected with the control module.

10. the fragment transferring device of punching according to claim 1-8, which is characterized in that point of the punching Piece transferring device further includes display, and the display is set in the rack, and the display and the control module are electrical Connection.