JP2018028188A - Turn angle detection device of construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To elongate a life of a lever for transmitting the turn displacement of the other side member to an angle sensor.SOLUTION: In a turn angle detection device 23 having an angle sensor 24 provided at a pin connecting part 15 between a boom 9 which is connected via a connecting pin 20 so as to be turnable, and an arm 10, and provided at an end part of the connecting pin 20, and a lever 25 for transmitting the turn displacement of the arm 10 to the angle sensor 24, the lever 25 includes an attachment baseboard 26 attached to an arm boss 17 of the arm 10, and a rod member 28 disposed between the attachment baseboard 26 and the angle sensor 24. A ring part 28D provided at a base end side of the rod member 28 is fixed to the attachment baseboard 26 by using a rod member fixing rivet 29, and a middle region which is shifted to a sensor attachment part 28E side rather than the ring part 28D of the rod member 28 is held by a holder member 30. The sensor attachment part 28E of the rod member 28 is attached to a rotating shaft 24B of the angle sensor 24.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a rotation angle detection device that is mounted on a construction machine such as a hydraulic excavator and is preferably used to detect a rotation angle between two members that are rotatably connected via a connecting pin.

  A hydraulic excavator, which is a typical example of a construction machine, includes a self-propelled lower traveling body, an upper revolving body that is pivotably mounted on the lower traveling body, and a front that is provided so as to be able to move up and down in front of the upper revolving body. And the device.

  A front device of a hydraulic excavator typically includes a boom that is pivotally attached to a pivot frame of an upper swing body via a connection pin, and an arm that is pivotally attached to the tip side of the boom via a connection pin. The bucket includes a bucket (working tool) rotatably attached to the distal end side of the arm via a connecting pin, and earth excavation work or the like is performed using the bucket. Further, in a crane-type hydraulic excavator in which a hanging load hook is stored in a bucket link, a crane operation can be performed using this hanging load hook by removing the hanging load hook from the bucket link.

  Here, an angle sensor is provided for each of the pin coupling portion between the boom and the swing frame, the pin coupling portion between the boom and the arm, and the pin coupling portion between the arm and the bucket that constitute the front device of the hydraulic excavator. Is provided, and a rotation angle between two members rotatably connected via a connecting pin is always detected by an angle sensor (see, for example, Patent Document 1).

  Thereby, the rotation angle of the boom with respect to the turning frame, the rotation angle of the arm with respect to the boom, and the rotation angle of the bucket with respect to the arm are detected by the angle sensor. And the position of the front-end | tip part of a bucket is calculated based on the detected rotation angle, for example, control which moves the front-end | tip part of a bucket in the range which does not interfere with a cab at the time of excavation work is performed. Also, the attitude of the front device is detected based on the detected rotation angle, for example, a control that issues an alarm or the like to the operator so that the front device does not become an unreasonable posture (a posture in which the vehicle body becomes unstable) during crane work, for example. Is done.

JP 2001-330022 A

  Here, the angle sensor by a prior art is attached to the edge part of the connection pin which connects between the front-end | tip of a boom and an arm, for example. The angle sensor and the arm are connected by a lever, and the rotational displacement of the arm with respect to the boom is transmitted to the angle sensor via the lever.

  By the way, the above-mentioned lever is usually formed by a flat plate-like plate attached to the arm and a round bar-like rod member attached to the angle sensor, and these plate and the bar member provide welding means. Are joined together. Thus, for example, when the distance between the arm and the angle sensor changes due to dimensional tolerance when the front device is assembled, or when stress is applied to the lever due to vibration transmitted from the front device to the lever during excavation work However, this stress can be absorbed by the bending deformation of the bar member.

  However, in the structure in which the plate member attached to the arm and the rod member attached to the angle sensor are joined by welding, such as a lever according to the prior art, a crack is caused by a weld defect in the joint portion, so that breakage of the lever is prevented. It becomes easy to invite. In particular, since the thickness (plate thickness) of the plate constituting the lever and the diameter of the bar member are small, it is difficult to weld the plate and the bar member, and welding is performed at the joint between the plate and the bar member. Defects are likely to occur. Furthermore, since the cross-sectional shape greatly changes at the joint between the plate and the bar member, the stress tends to concentrate on the joint between the plate and the bar member, and the life of the lever is reduced.

  The present invention has been made in view of the above-described problems of the prior art, and provides a rotation angle detection device for a construction machine that can extend the life of a lever that transmits the rotation displacement of the other side member to the angle sensor. The purpose is to do.

  In order to solve the above-described problems, the present invention is applied to a construction machine including one side member and another side member that are rotatably connected via a connection pin, and the other side member is connected to the one side member. An angle sensor provided at an end of the connecting pin to detect a rotation angle, and a rotation displacement of the other side member provided between the other side member and the angle sensor is transmitted to the angle sensor. And a lever for detecting a rotation angle of a construction machine.

  A feature of the configuration adopted by the present invention is that the lever is a mounting substrate that is attached to the other side member and extends toward the angle sensor, a base end side is a substrate fixing portion that is fixed to the mounting substrate, and a distal end side is A rod member serving as a sensor attachment portion attached to the angle sensor, a rod member fixing rivet for fixing the substrate fixing portion of the rod member to the attachment substrate, and the sensor attachment than the substrate fixing portion of the rod member In order to hold an intermediate part biased to the part side, the holder member is fixed to the mounting substrate.

  According to the present invention, the board fixing portion of the bar member can be fixed to the mounting board using the bar member fixing rivet without using welding means. Thereby, compared with the structure which joins a rod member and an attachment board | substrate by welding, for example, generation | occurrence | production of the crack by a welding defect and the stress concentration accompanying the sudden change of a cross-sectional shape of a junction part can be avoided. As a result, the stress acting on the lever can be absorbed by the bending deformation of the rod member, and the life of the lever can be extended.

1 is a front view showing a hydraulic excavator equipped with a rotation angle detection device according to a first embodiment of the present invention. It is an enlarged front view which expands and shows the pin coupling | bond part of the boom and arm in FIG. It is sectional drawing which looked at the boom, the arm, the connection pin, the rotation angle detection device, etc. from the direction of arrows III-III in FIG. It is a perspective view which shows the lever of a rotation angle detection apparatus alone. It is a disassembled perspective view which shows the attachment board | substrate which comprises a lever, a bar member, a bar member fixed rivet, a holder member. It is a side view of a lever simple substance. It is the front view which looked at the lever from the arrow VII-VII direction in FIG. It is sectional drawing which looked at the attachment board | substrate, the rod member, the holder member, the holder fixing rivet, etc. from the arrow VIII-VIII direction in FIG. It is the front view which looked at the lever by 2nd Embodiment from the same position as FIG. It is a disassembled perspective view similar to FIG. 5 which shows the lever provided with the attachment board | substrate by 3rd Embodiment.

  Hereinafter, a case where the rotation angle detection device for a construction machine according to an embodiment of the present invention is applied to a pin coupling portion between a boom and an arm of a hydraulic excavator will be described as an example, and will be described in detail with reference to FIGS. explain.

  1 to 8 show a first embodiment of the present invention. A hydraulic excavator 1, which is a typical example of a construction machine, includes a self-propelled crawler-type lower traveling body 2, an upper revolving body 3 that is turnably mounted on the lower traveling body 2, and a front side of the upper revolving body 3. It includes a front device 8 which will be described later and which performs soil excavation work and the like.

  The upper swing body 3 includes a swing frame 4 serving as a base, a counterweight 5 provided on the rear end side of the swing frame 4, a prime mover and a hydraulic pump mounted on the swing frame 4 positioned on the front side of the counterweight 5. A mounted device (not shown) such as a heat exchange device, an exterior cover 6 provided on the revolving frame 4 so as to cover the mounted device, and a cab 7 provided on the left front side of the revolving frame 4 and defining a cab. It is comprised including.

  The front device 8 is provided on the front side of the revolving frame 4 constituting the upper revolving structure 3 so as to be able to move up and down. The front device 8 includes a boom 9 whose base end side (foot portion) is pivotally coupled to the front side of the revolving frame 4 so as to be pivotable upward and downward, and is pivotally coupled to the distal end side of the boom 9. The arm 10 is configured to include a bucket 11 as a work tool that is pivotally coupled to the distal end side of the arm 10. The boom 9 is driven by the boom cylinder 9A, the arm 10 is driven by the arm cylinder 10A, and the bucket 11 is driven by the bucket cylinder 11A.

  Here, bucket links 12 and 13 are provided between the bucket 11 and the rod of the bucket cylinder 11 </ b> A, and the expansion and contraction of the bucket cylinder 11 </ b> A is transmitted to the bucket 11 via the bucket links 12 and 13. The bucket link 12 is configured to include left and right link plates 12A (only the left side is illustrated) facing each other in the left and right directions, and a hanging load hook 14 is rotatably provided between the link plates 12A. ing.

  The hanging load hook 14 is disposed between the left and right link plates 12 </ b> A constituting the bucket link 12. The suspended load hook 14 is held at the retracted position stored between the link plates 12A when the excavator 1 is used to excavate earth and sand. Further, when carrying out crane work using the hanging load hook 14, the hanging load hook 14 is configured to be taken out of the bucket link 12.

  Next, the pin coupling portion 15 that rotatably connects the boom 9 as one side member and the arm 10 as the other side member constituting the front device 8 will be described.

  As shown in FIG. 3, the pin coupling portion 15 includes a pair of left and right brackets 16 provided on the distal end side of the boom 9, an arm boss 17 provided on the arm 10, and a connecting pin 20 described later. It is configured.

  Each bracket 16 of the boom 9 is provided with a reinforcing plate 16A on the outer surface thereof, and a pin insertion hole 16B through which the connecting pin 20 is inserted is formed through each bracket 16 and the reinforcing plate 16A so as to penetrate left and right. Has been. Each bracket 16 is disposed so as to sandwich the arm boss 17 from both the left and right sides, and each bracket 16 and the arm boss 17 are connected to each other so as to be relatively rotatable about a connecting pin 20.

  The arm boss 17 is integrally provided on the base end side of the arm 10 and is formed in a cylindrical shape extending in the left and right directions. The inner peripheral side of the arm boss 17 is a pin insertion hole 17A, and bushes 19 to be described later are disposed on both end sides in the axial direction of the pin insertion hole 17A. Arc-shaped flange plates 17B are integrally provided at both ends of the arm boss 17 in the axial direction, and the outer peripheral edges of the left and right flange plates 17B are welded to the left and right side plates 10B of the arm 10, respectively. A lever mounting base 17C for mounting a lever 25 described later is fixed to the outer surface of one (left side in FIG. 3) flange plate 17B by means such as welding.

  The stopper protrusion 18 is fixed to the reinforcing plate 16A of one of the brackets 16 (left side in FIG. 3) by means of welding or the like, and is outward (in a direction away from the bracket 16) from the reinforcing plate 16A. It protrudes. The stopper projection 18 is formed in, for example, a stepped cylindrical shape, and is configured to stop the connection pin 20 with respect to the bracket 16 by being fitted into a long groove hole 21 </ b> A of a rotation stop flange 21 described later. A female screw hole 18 </ b> A is screwed on the inner peripheral side of the stopper protrusion 18.

  The pair of bushes 19 are disposed on both the left and right sides of the arm boss 17. Each bush 19 is formed as a cylindrical body made of a hard metal material having excellent wear resistance, for example. Each bush 19 is fitted to the inner peripheral side of the arm boss 17 by using means such as press-fitting, for example, and the inner peripheral side of each bush 19 is a pin insertion hole into which the connecting pin 20 is slidably inserted. 19A.

  The connecting pin 20 connects each bracket 16 and the arm boss 17 and is formed in a columnar shape using a metal material. The connecting pin 20 is slidably inserted into a pin insertion hole 19A of each bush 19 provided in the arm boss 17 at an axial intermediate portion, and both end sides in the axial direction are inside the pin insertion holes 16B of the brackets 16. Is inserted.

  One end side of the connecting pin 20 in the axial direction is a large diameter portion 20A, and the large diameter portion 20A is provided with a stopper projection 18 in a state where both end sides of the connecting pin 20 are inserted into the pin insertion holes 16B of the brackets 16. The bracket 16 protrudes outside the reinforcing plate 16A. A bottomed hole 20B extending in the axial direction is formed on the end face of the large diameter portion 20A, and an angle sensor 24 described later is accommodated in the bottomed hole 20B.

  A detent flange 21 is fixed to the outer periphery of the large-diameter portion 20A of the connecting pin 20. The detent flange 21 is made of a substantially flat metal plate, and one end in the length direction of the detent flange 21 is integrated with the outer peripheral surface of the large-diameter portion 20A using means such as welding. It is fixed to. On the other hand, a long groove hole 21 </ b> A extending along the length direction is formed on the other end side in the length direction of the locking flange 21.

  Here, the locking flange 21 locks the connecting pin 20 with respect to the one bracket 16 by fitting the long groove hole 21A to the stopper projection 18 provided on the one bracket 16 (reinforcing plate 16A). It has a configuration. Further, a retaining plate 22 is attached to the protruding end of the stopper protrusion 18 in a state where the long groove hole 21 </ b> A of the stopper flange 21 is fitted to the stopper protrusion 18. The retaining plate 22 is formed in a disk shape having a diameter larger than the groove width of the long groove hole 21A, and a bolt 22A inserted through the central portion of the retaining plate 22 is screwed into the female screw hole 18A of the stopper protrusion 18, thereby It is fixed to the protruding end of the protrusion 18. Accordingly, the connecting pin 20 is stopped by the stopper protrusion 18 and the stop flange 21 and is prevented from being removed in the axial direction by the retaining plate 22.

  Next, the rotation angle detection device 23 used in the present embodiment will be described.

  The rotation angle detection device 23 is provided between the arm 10 and the connecting pin 20 and detects the rotation angle of the arm 10 (other side member) relative to the boom 9 (one side member). The rotation angle detection device 23 includes a later-described angle sensor 24 provided on the connecting pin 20 and a later-described lever 25 provided between the arm 10 and the angle sensor 24.

  The angle sensor 24 is provided in the bottomed hole 20 </ b> B of the large-diameter portion 20 </ b> A that becomes the end of the connecting pin 20. The angle sensor 24 has a cylindrical casing 24A inserted into the bottomed hole 20B, and a rotation shaft 24B for angle detection provided rotatably in the casing 24A. The angle sensor 24 has a detection unit (not shown) such as a potentiometer that detects the rotational position of the rotary shaft 24B, and detects the rotation angle θ of the arm 10 relative to the boom 9 with the connecting pin 20 as the center. is there.

  Here, the rotation shaft 24B of the angle sensor 24 is arranged concentrically with the shaft center of the connecting pin 20, and a lever mounting hole 24C penetrating in the radial direction is formed at the protruding end of the rotation shaft 24B protruding from the casing 24A. Is formed. The rotation shaft 24B of the angle sensor 24 and the arm 10 are connected via a lever 25 described later, and when the boom 9 and the arm 10 are rotated relative to each other about the connecting pin 20, the boom 9 is moved. The rotation angle θ of the arm 10 is configured to be detected by the angle sensor 24.

  Next, the lever 25 used in the present embodiment will be described with reference to FIGS.

  The lever 25 is provided between the arm 10 and the angle sensor 24 and detects the rotation angle θ of the arm 10 with respect to the boom 9. Here, the lever 25 includes a mounting board 26, a bar member 28, a bar member fixing rivet 29, and a holder member 30, which will be described later.

  The mounting board 26 is mounted on a lever mounting base 17 </ b> C provided on the arm boss 17 and extends toward the angle sensor 24. The mounting substrate 26 is formed as a substantially J-shaped bent plate having a thickness of about 2 mm, for example, by bending a rectangular plate made of a stainless steel plate or the like. The mounting board 26 is formed with a bent portion 26A at an intermediate portion in the length direction, and has a short flat plate-like fixing plate 26B and a long bar member mounting plate 26C with the bent portion 26A interposed therebetween. .

  The fixing plate 26 </ b> B of the mounting substrate 26 is provided with an elongated hole insertion hole 26 </ b> D that extends in the length direction of the mounting substrate 26. The bolt 27 inserted through the bolt insertion hole 26D is screwed to the lever mounting base 17C of the arm boss 17, whereby the fixing plate 26B of the mounting board 26 is fixed to the lever mounting base 17C, and the bar member mounting plate 26C is an angle sensor. 24 (see FIG. 3).

  One oblong rivet fitting hole 26E and two rivet fitting holes 26F are provided on the distal end side (the side opposite to the bent portion 26A) of the rod member mounting plate 26C of the mounting substrate 26. The oval rivet fitting hole 26E is formed in the shape of a long hole extending in the width direction orthogonal to the length direction of the mounting substrate 26, and is disposed at the center in the width direction of the bar member mounting plate 26C. The oval rivet fitting hole 26E is for fitting a shaft portion 29A of a rod member fixing rivet 29 described later.

  On the other hand, the rivet fitting hole 26F is located on the tip side of the oval rivet fitting hole 26E, and is arranged with a gap in the width direction of the rod member mounting plate 26C. Each of these rivet fitting holes 26F is for fitting a shaft portion 32A of a holder fixing rivet 32 described later.

  The rod member 28 has a proximal end fixed to the mounting substrate 26 and a distal end attached to the angle sensor 24. The bar member 28 is formed as a bent bar bent into a substantially J shape by bending a single round bar made of stainless steel for springs and having an outer diameter of about 3 mm and excellent in elasticity. The rod member 28 is formed with a bent portion 28A at a substantially central portion in the length direction, a substrate side rod portion 28B positioned on the mounting substrate 26 side with the bent portion 28A interposed therebetween, and an angle sensor 24 with the bent portion 28A interposed therebetween. It is comprised by the sensor side stick | rod part 28C located in the side.

  A ring portion 28D as a substrate fixing portion is formed at the end of the substrate-side bar portion 28B. The ring portion 28D is formed in a ring shape by winding and bending the end portion of the substrate side rod portion 28B around a shaft body or the like (not shown). The ring portion 28D is configured such that the shaft portion 29A of the rod member fixing rivet 29 is inserted into the inner peripheral side of the ring portion 28D, and the inner diameter dimension of the ring portion 28D is slightly larger than the outer diameter dimension of the shaft portion 29A. Yes. In this way, by forming the ring portion 28D by curving the end portion of the substrate-side rod portion 28B, the rod member 28 can be easily formed simply by bending a single round rod material. It can be configured.

  On the other hand, the sensor side bar portion 28C extends in a direction orthogonal to the axis center of the rotation shaft 24B constituting the angle sensor 24, and an end portion of the sensor side bar portion 28C serves as a sensor attachment portion 28E. The sensor attachment portion 28E is attached to the angle sensor 24 by being inserted into a lever attachment hole 24C formed in the rotation shaft 24B of the angle sensor 24.

  The bar member fixing rivet 29 fixes the ring portion 28 </ b> D of the bar member 28 to the mounting substrate 26. The rod member fixing rivet 29 includes a cylindrical shaft portion 29A and a disk-shaped head portion 29B provided on one end side of the shaft portion 29A. The shaft portion 29A of the rod member fixing rivet 29 is inserted into the ring portion 28D of the rod member 28 and the oval rivet fitting hole 26E of the mounting substrate 26.

  Then, the other end side of the shaft portion 29A protruding to the back surface 26G side of the mounting substrate 26 through the oval rivet fitting hole 26E is caulked using a tool such as a hammer (not shown). As a result, a caulking portion 29C is formed at the other end of the shaft portion 29A, and the caulking portion 29C is retained with respect to the oval rivet fitting hole 26E of the mounting substrate 26, whereby the ring portion of the bar member 28 is secured. 28D is fixed to the bar member mounting plate 26C of the mounting substrate 26.

  Here, the ring portion 28 </ b> D of the rod member 28 is formed by bending the substrate-side rod portion 28 </ b> B of the rod member 28. For this reason, when the shaft portion 29A of the rod member fixing rivet 29 is inserted into the inner peripheral side of the ring portion 28D, the center of the shaft portion 29A is relative to the axial center line of the rod member 28 (substrate-side rod portion 28B). May be decentered. Therefore, a circular rivet fitting hole is formed instead of the oval rivet fitting hole 26E at the center in the width direction of the attachment substrate 26 (rod member attachment plate 26C), and the rod member is formed in the rivet fitting hole. When the shaft portion 29 </ b> A of the fixed rivet 29 is fitted, the rod member 28 is fixed to the mounting substrate 26 with the axial center line of the rod member 28 shifted in the width direction with respect to the central portion of the mounting substrate 26. Will be. On the other hand, by forming an oval rivet fitting hole 26E extending in the width direction of the mounting board 26 in the bar member mounting plate 26C of the mounting board 26, the center of the shaft portion 29A of the bar member fixing rivet 29 is Even if it is deviated from the axial center line of the member 28, the position where the shaft portion 29A is fitted can be adjusted in the width direction along the oval rivet fitting hole 26E. Thereby, the bar member 28 can be fixed to the center portion in the width direction of the mounting substrate 26.

  In this way, the ring portion 28D can be formed on the rod member 28, and the ring portion 28D can be fixed to the mounting substrate 26 using the rod member fixing rivet 29. Therefore, the rod member 28 is attached to the mounting substrate 26 using welding means. There is no need to join it. As a result, it is possible to avoid the occurrence of cracks due to welding defects and stress concentration due to the change in the cross-sectional shape of the joint portion between the rod member 28 and the mounting substrate 26. Further, as compared with the case where the bar member 28 and the mounting board 26 are joined by welding, the bar member 28 and the mounting board 26 can be easily joined using the bar member fixing rivet 29. .

  The holder member 30 is fixed to the tip end side of the rod member mounting plate 26 </ b> C of the mounting substrate 26. The holder member 30 holds a part of the board-side bar portion 28B of the bar member 28 that is biased toward the sensor mounting portion 28E rather than the ring portion 28D. Here, the holder member 30 includes a holder main body 31 and a holder fixing rivet 32 which will be described later.

  The holder main body 31 is formed in a rectangular plate shape that extends in the width direction of the mounting substrate 26 as a whole by using, for example, a stainless steel plate that is thinner than the mounting substrate 26. Here, the holder main body 31 includes a bent portion 31A having a triangular cross section located at the center in the length direction and a pair of substrate contact portions 31B disposed on both sides in the length direction with the bent portion 31A interposed therebetween. The bent portion 31A is formed by bending, for example. Each board contact portion 31B is provided with a rivet fitting hole 31C, and each rivet fitting hole 31C corresponds to each rivet fitting hole 26F of the mounting board 26.

  Here, as shown in FIG. 8, the bent portion 31 </ b> A of the holder main body 31 sandwiches the board-side bar portion 28 </ b> B of the bar member 28 between the holder member 26 and the bar member mounting plate 26 </ b> C. Each substrate contact portion 31B of the holder main body 31 is in contact with the rod member mounting plate 26C of the mounting substrate 26. In this case, when the bent portion 31A of the holder body 31 is formed in a triangular cross section, the substrate side rod portion 28B of the rod member 28 is sandwiched between the bent portion 31A and the rod member mounting plate 26C. The outer peripheral surface of the side bar portion 28B is supported at three points by the bent portion 31A and the bar member mounting plate 26C. Therefore, the bent portion 31A of the holder main body 31 stably holds the substrate-side rod portion 28B in a state where it covers the outer peripheral surface of the substrate-side rod portion 28B, and the rod member 28 is displaced (deformed) in the width direction of the mounting substrate 26. ).

  The holder fixing rivet 32 fixes each substrate contact portion 31 </ b> B of the holder body 31 to the rod member mounting plate 26 </ b> C of the mounting substrate 26. The holder fixing rivet 32 includes a cylindrical shaft portion 32A and a head portion 32B provided on one end side of the shaft portion 32A. The shaft portion 32A of the holder fixing rivet 32 is inserted into the rivet fitting hole 31C of each substrate contact portion 31B and the rivet fitting hole 26F of the mounting substrate 26.

  Then, in a state where the ring portion 28D of the bar member 28 is fixed to the bar member mounting plate 26C of the mounting substrate 26 by the bar member fixing rivet 29, the bar member is interposed between the bar member mounting plate 26C and the bent portion 31A of the holder body 31. 28 substrate-side bar portions 28B are sandwiched. In this state, the shaft portions 32A of the holder fixing rivets 32 are inserted into the rivet fitting holes 31C of the holder main body 31 and the rivet fitting holes 26F of the mounting substrate 26, respectively. The other end side of the shaft portion 32A protruding to the back surface 26G side of the mounting substrate 26 through the rivet fitting hole 26F is caulked using a tool (not shown) such as a hammer. As a result, a caulking portion 32C is formed at the other end of the shaft portion 32A. The caulking portion 32C is prevented from being removed from the rivet fitting hole 26F of the mounting substrate 26, so that the holder body 31 is attached to the mounting substrate 26. It is fixed to the rod member mounting plate 26C.

  In this way, the ring portion 28D of the rod member 28 is fixed to the rod member mounting plate 26C of the mounting substrate 26 using the rod member fixing rivet 29, and is closer to the sensor mounting portion 28E side than the ring portion 28D of the rod member 28. The biased midway portion is held by the holder member 30 on the bar member mounting plate 26C of the mounting substrate 26. Thereby, the rod member 28 is bent and deformed (elastically deformed) in the plate thickness direction (direction indicated by arrow A in FIG. 6) of the mounting substrate 26 by its own elasticity, and the holder member 30 moves in the width direction of the mounting substrate 26. The deformation is restricted.

  Thus, the lever 25 according to the present embodiment uses the welding means by fixing the ring portion 28D provided on the base end side of the bar member 28 to the mounting substrate 26 using the bar member fixing rivet 29. Therefore, since it is not necessary to fix the rod member 28 to the mounting substrate 26, the rod member 28 having excellent elasticity can be formed using stainless steel for springs which is difficult to weld. Thereby, the rod member 28 is attached to the attachment substrate 26 in a state in which it can be bent and deformed (elastically deformed) with respect to the thickness direction of the attachment substrate 26 (the direction indicated by the arrow A in FIG. 6). Therefore, for example, as shown in FIG. 3, the distance L between the end surface of the lever mounting base 17 </ b> C provided on the arm boss 17 and the center of the lever mounting hole 24 </ b> C of the angle sensor 24 is a dimension when the front device 8 is assembled. Even if a stress is applied to the rod member 28 due to a change in the tolerance range and the distance L is changed, the stress can be absorbed by the deflection of the rod member 28.

  The protective cover 33 is attached to the anti-rotation flange 21 so as to cover the rotation angle detection device 23. The protective cover 33 is formed as a covered cylinder having a substantially elliptical shape, and is attached to the locking flange 21 using a plurality of spacers 33A and bolts 33B. The protective cover 33 protects the angle sensor 24, the lever 25, and the like from earth and sand during excavation work by covering the angle sensor 24, the lever 25, and the like that constitute the rotation angle detection device 23.

  The rotation angle detection device 23 according to the present embodiment has the above-described configuration, and the operation thereof will be described below.

  When the excavator 1 performs a crane operation using the hanging load hook 14 and an excavation operation using the bucket 11, the rotation angle of the arm 10 with respect to the boom 9 is detected by the rotation angle detection device 23.

  That is, when the arm cylinder 10A extends or contracts and the arm 10 rotates about the connecting pin 20 on the distal end side of the boom 9, the rotation axis 24B of the angle sensor 24 provided at the end of the connecting pin 20 On the other hand, the turning motion of the arm 10 is transmitted via the lever 25. Thereby, the angle sensor 24 can detect the rotation angle θ of the arm 10 with respect to the boom 9 based on the rotation displacement of the rotation shaft 24B.

  In this case, the lever 25 of the rotation angle detecting device 23 according to the present embodiment includes an attachment board 26 attached to the arm boss 17 of the arm 10 and a bar member 28 provided between the attachment board 26 and the angle sensor 24. And a ring portion 28D provided on the base end side of the bar member 28 is fixed to the mounting substrate 26 by using a bar member fixing rivet 29, and more than the ring portion 28D of the bar member 28. An intermediate portion (substrate-side bar portion 28B) that is biased toward the sensor attachment portion 28E is held by the holder member 30.

  Therefore, the lever 25 according to the present embodiment does not need to fix the bar member 28 to the mounting substrate 26 by using welding means. Therefore, the bar member 28 having excellent elasticity using spring stainless steel which is difficult to weld is used. The rod member 28 can be sufficiently bent and deformed (elastically deformed) in the thickness direction of the mounting substrate 26. As a result, for example, as shown in FIG. 3, the distance L between the end surface of the lever mounting base 17 </ b> C provided on the arm boss 17 and the center of the lever mounting hole 24 </ b> C of the angle sensor 24 is determined when the front device 8 is assembled. It changes within the range of the dimensional tolerance, and the change of the distance L may cause a force to act on the rod member 28 to generate a stress. Even if stress is generated in the bar member 28, a material having high mechanical performance can be used for the bar member 28, so that the stress can be kept within the allowable stress value. Further, for example, even when a force is applied to the rod member 28 due to vibration transmitted from the front device 8 to the lever 25 during the operation of the hydraulic excavator 1, the same effect can be obtained.

  Here, if the rod member 28 is joined to the mounting substrate 26 by welding, stress concentration occurs due to the occurrence of cracks due to welding defects or the change in cross-sectional shape at the joint between the mounting substrate 26 and the rod member 28. As a result, there is a risk of damage to the welded joint.

  On the other hand, in the present embodiment, the ring portion 28D provided on the base end side of the rod member 28 is fixed to the mounting substrate 26 using the rod member fixing rivet 29, and the ring portion 28D of the rod member 28 is also fixed. Further, the intermediate portion (substrate-side bar portion 28B) that is biased toward the sensor mounting portion 28E side is held by the holder member 30. As a result, compared with the case where the bar member 28 is joined to the mounting substrate 26 using welding means, it is possible to suppress the concentration of stress on the fixing portion between the bar member 28 and the mounting substrate 26, and the lever 25. Durability can be increased and its life can be extended.

  In addition, the lever 25 of the rotation angle detection device 23 according to the present embodiment forms a ring portion 28D curved in a ring shape on the proximal end side of the rod member 28, and the mounting substrate 26 has an inner portion of the ring portion 28D. An oblong rivet fitting hole 26E having a long hole shape with which the rod member fixing rivet 29 inserted on the circumferential side is fitted is provided.

  As a result, the bar member 28 having the ring portion 28D can be easily formed simply by bending the single round bar, so that the manufacturing cost of the lever 25 can be reduced. In addition, even when the shaft portion 29A of the rod member fixing rivet 29 is inserted into the inner peripheral side of the ring portion 28D, even if the center of the shaft portion 29A is deviated from the axial center line of the rod member 28, the shaft portion 29A. The bar member 28 can be fixed to the center portion in the width direction of the mounting substrate 26 by adjusting the position where the two are fitted in the width direction along the oval rivet fitting hole 26E.

  Further, the lever 25 of the rotation angle detection device 23 according to the present embodiment sandwiches the bent portion 31A having a triangular section and the bent portion 31A with the holder member 30 sandwiching the rod member 28 with the mounting substrate 26. And a holder main body 31 having a pair of substrate abutting portions 31B that abut on the mounting substrate 26 and holder fixing rivets 32 for fixing the substrate abutting portions 31B of the holder main body 31 to the mounting substrate 26. ing.

  As a result, when the bar member 28 (substrate-side bar portion 28B) is sandwiched between the bent portion 31A having a triangular cross section and the mounting substrate 26, the outer peripheral surface of the bar member 28 is set to the bent portion 31A and the mounting substrate 26. 3 points can be supported. As a result, the bent portion 31A of the holder body 31 stably holds the substrate-side rod portion 28B in a state of covering the outer peripheral side of the substrate-side rod portion 28B, and the rod member 28 is displaced in the width direction of the mounting substrate 26 ( Deformation).

  Next, FIG. 9 shows a second embodiment of the present invention. The feature of the second embodiment resides in that a notch is provided in the bent portion of the holder main body constituting the holder member. In the second embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and description thereof is omitted.

  The holder member 34 used in the second embodiment includes a holder main body 35 and a holder fixing rivet 32, which will be described later, in substantially the same manner as the holder member 30 according to the first embodiment. However, the holder member 34 is different from that according to the first embodiment in that a notch 36 is provided in the bent portion 35A of the holder main body 35.

  The holder body 35 is formed in a rectangular plate shape extending in the width direction of the mounting substrate 26, and has a bent portion 35A having a triangular cross section located at the center in the length direction and both sides in the length direction across the bent portion 35A. And a pair of substrate abutting portions 35B disposed on the surface. The bent portion 35A of the holder main body 35 stably holds the substrate-side rod portion 28B in a state of covering the outer peripheral surface of the substrate-side rod portion 28B, and the rod member 28 is displaced (deformed) in the width direction of the mounting substrate 26. To limit. Each board contact portion 35B is provided with a rivet fitting hole 35C, and each rivet fitting hole 35C corresponds to each rivet fitting hole 26F of the mounting board 26.

  The cutout portion 36 is provided in the bent portion 35 </ b> A of the holder main body 35. That is, the notch 36 is formed by notching a portion of the bent portion 35A located on the opposite side of the bar member fixing rivet 29 into a substantially V shape. As a result, the length of the bar member 28 sandwiched between the bent portion 35A and the mounting substrate 26 (bar member mounting plate 26C) is shortened, and the bar member 28 correspondingly extends in the plate thickness direction of the mounting substrate 26. The structure can be greatly bent and deformed.

  The rotation angle detection device according to the second embodiment has the holder member 34 as described above, and there is no particular difference in basic operation from that according to the first embodiment.

  However, according to the second embodiment, the bar member 28 is greatly bent in the plate thickness direction of the mounting substrate 26 by the amount of the notch 36 provided in the bent portion 35A of the holder main body 35 constituting the holder member 34. It can be deformed.

  Next, FIG. 10 shows a third embodiment of the present invention. A feature of the third embodiment resides in that a circular circular rivet fitting hole is provided in the rod member mounting plate of the mounting substrate in place of the oblong elliptical rivet fitting hole. Note that in the third embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and description thereof is omitted.

  The mounting board 26 'used in the third embodiment has a fixed plate 26B and a bar member mounting plate 26C with a bent portion 26A sandwiched therebetween, almost like the mounting board 26 according to the first embodiment. Two rivet fitting holes 26F are formed in the rod member mounting plate 26C. However, the rod member mounting plate 26C of the mounting board 26 'is provided with a circular rivet fitting hole 26E' formed of a circular hole instead of the oval rivet fitting hole 26E according to the first embodiment. Thus, it is different from that according to the first embodiment.

  One circular rivet fitting hole 26E 'is provided at the center in the width direction of the rod member mounting plate 26C. The circular rivet fitting hole 26E ′ is for fitting the shaft portion 29A of the rod member fixing rivet 29 inserted into the ring portion 28D of the rod member 28. Here, the circular rivet fitting hole 26 </ b> E ′ has a hole diameter slightly larger than the outer diameter of the shaft portion 29 </ b> A of the rod member fixing rivet 29. Accordingly, even when the shaft portion 29A of the rod member fixing rivet 29 is inserted into the ring portion 28D of the rod member 28, even if the center of the shaft portion 29A is deviated from the axial center line of the rod member 28, the rod The position where the shaft portion 29A of the member fixing rivet 29 is fitted can be adjusted within the range of the circular rivet fitting hole 26E ′. As a result, the rod member 28 can be fixed to the central portion in the width direction of the mounting substrate 26 '.

  In the embodiment, the rotation angle detection device 23 provided in the pin coupling portion 15 between the boom 9 and the arm 10 is described as an example of the rotation angle detection device. However, the present invention is not limited to this. For example, a rotation angle detection provided at a pin coupling portion between the swing frame 4 and the foot portion of the boom 9, a pin coupling portion between the arm 10 and the bucket 11, or the like. It can also be applied to devices.

  Moreover, in embodiment, the case where the rod member 28 is formed using the stainless steel for springs is illustrated. However, the present invention is not limited to this, and the rod member 28 may be formed using, for example, high tensile steel having excellent elasticity.

9 Boom (one side member)
10 Arm (other side member)
DESCRIPTION OF SYMBOLS 20 Connection pin 23 Rotation angle detection apparatus 24 Angle sensor 25 Lever 26,26 'Mounting board 26E Oval rivet fitting hole 28 Bar member 28D Ring part (board | substrate fixing | fixed part)
28E Sensor mounting portion 29 Bar member fixing rivet 30, 34 Holder member 31, 35 Holder body 31A, 35A Bending portion 31B, 35B Substrate contact portion 32 Holder fixing rivet 36 Notch

Claims (5)

Applied to a construction machine having one side member and another side member rotatably connected via a connection pin, and for detecting the rotation angle of the other side member with respect to the one side member, Rotation of a construction machine comprising: an angle sensor provided at an end; and a lever provided between the other side member and the angle sensor that transmits a rotation displacement of the other side member to the angle sensor. In the angle detector,
The lever is
A mounting substrate attached to the other member and extending toward the angle sensor;
A base member whose base end side is a substrate fixing portion fixed to the mounting substrate, and whose tip side is a sensor mounting portion attached to the angle sensor;
A rod member fixing rivet for fixing the substrate fixing portion of the rod member to the mounting substrate;
In order to hold an intermediate portion of the bar member that is biased toward the sensor mounting portion side with respect to the substrate fixing portion, a holder member fixed to the mounting substrate is used. Moving angle detector. The substrate fixing part of the bar member is formed by a ring part in which the base end side of the bar member is curved in a ring shape,
The mounting board is provided with an oblong rivet fitting hole having a long hole shape into which the rod member fixing rivet inserted into the inner peripheral side of the ring portion of the rod member is fitted. The rotation angle detection device for a construction machine according to claim 1. The holder member is
A holder body having a bent portion having a triangular cross-section sandwiching the rod member with the mounting substrate and a pair of substrate contacting portions disposed on both sides of the bent portion and contacting the mounting substrate;
2. The rotation angle detection device for a construction machine according to claim 1, wherein the rotation angle detection device is constructed of a holder fixing rivet that fixes each of the substrate contact portions of the holder body to the mounting substrate.   The bent portion of the holder main body constituting the holder member is provided with a notch portion that allows the rod member to bend and deform in the plate thickness direction of the mounting substrate. 4. A rotation angle detection device for a construction machine according to 3.   The rotation angle detecting device for a construction machine according to claim 1, wherein the bar member is formed using stainless steel for a spring.

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