JP2005083106A - Working machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily install a stroke sensor for detecting a boom angle, in a state of being protected by a cover from sediment and contact with an upper frame or the like and moreover by after-fitting. <P>SOLUTION: A hydraulic shovel is provided with a cylinder protective cover 16 outside a boom cylinder 6 for derricking a boom in a working device. One end of a wire 18 is fastened to the inside of the cylinder protective cover 16, and a sensor body part 20 comprising a wire reel 21 and a signal converter 22 is provided at the upper part of a cylinder tube 6b always covered with the cylinder protective cover 16, and constituted to detect the moving quantity of the cylinder protective cover 16 as the stroke of the boom cylinder 6. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a work machine such as a hydraulic excavator having a crane function.

  A conventional technique and problems will be described by taking a hydraulic excavator as an example.

  FIG. 8 shows a small hydraulic excavator called a mini excavator. Reference numeral 1 denotes a crawler-type lower traveling body. An upper revolving body 2 is mounted on the lower traveling body 1 so as to be rotatable about a vertical axis to form an excavator body (machine main body). The working device A is mounted on

  In the working device A, an arm 4 is attached to the tip of a boom 3 attached to the upper swing body 2 so as to be raised and lowered, and a bucket 5 is attached to the tip of the arm 4 so as to be rotatable around a horizontal axis. A boom cylinder 6 between the boom 3 and the boom 3, an arm cylinder 7 between the boom 3 and the arm 4, and a bucket cylinder 8 between the arm 4 and the bucket 5. 3, the relative rotation movement of the arm 4 with respect to the boom 3, and the relative rotation movement of the bucket 5 with respect to the arm 4, the entire work apparatus A bends and stretches to perform excavation operation.

  In the figure, a swing-type excavator that swings the working device A to the left and right is illustrated, and a swing bracket 10 is attached to the upper frame 9 of the upper swing body 2 so as to be rotatable about the vertical axis. The boom 3 is attached to the bracket 10. In FIG. 8, reference numeral 11 denotes a driver seat provided on the upper swing body 2.

  Such a hydraulic excavator is well known in that a suspension hook 12 is attached to the bucket 5 of the working device A and a crane function for lifting the load W is provided.

  Further, in this excavator with a crane function, it is necessary to monitor the ground angle of the boom 3 and the angle of the arm 4 with respect to the boom 3 from the necessity of preventing overload during crane operation.

  Therefore, angle sensors 13 and 14 are provided at the boom mounting portion with respect to the upper swing body 2 and the connecting portion between the boom 3 and the arm 4, respectively.

  The angle sensors 13 and 14 are configured so that, for example, the relative rotation amount of the two joined members is taken into a sensor main body such as a potentiometer by a link and converted into an electrical signal, and this detection signal is provided in the upper swing body 2. The load is calculated by inputting to a controller (not shown).

  As another angle detection method, there is known a method of detecting the stroke of the boom cylinder 6 or the arm cylinder 7 and converting the cylinder stroke into a boom angle (see Patent Documents 1 and 2).

  On the other hand, for each of the cylinders 6, 7, and 8, in particular, a cylinder protection cover provided outside the cylinder in order to protect the piston rod from earth and sand is known (see Patent Document 3).

FIG. 9 illustrates the protective cover 15 of the boom cylinder 6. One end of the cover 15 is fixed to the tip of the piston rod 6a so as to cover almost the outer half of the piston rod 6a, and slides integrally with the piston rod 6a to protect the rod 6a over the entire expansion / contraction range. To do.
Japanese Patent Laid-Open No. 62-83995 Japanese Utility Model Publication No. 1-92505 Japanese Utility Model Publication No. 62-35071

  However, the conventional hydraulic excavator has the following problems regarding the angle detection of the boom 3 and the arm 4.

  Taking the angle detection part of the boom 3 as an example, as shown in FIG. 9, the angle sensor 13 is provided on the side surface of the joint part of the upper frame 9 and the boom 3, so that it is easy to come into contact with earth and sand.

  In particular, in the case of a swing type excavator, the angle sensor 13 is attached to the swing bracket 10, so that it is easy to come into contact with a structure such as the upper frame 9 during the swing, which may cause damage.

  As a countermeasure against this point, it is conceivable to provide a dedicated protective cover for the angle sensor 13, but adding the protective cover increases the cost for installing the sensor, and in a small machine such as a mini excavator, the space is reduced. It is difficult to add a cover because of limitations.

  On the other hand, when a method of detecting the stroke of the boom cylinder 6 with a built-in stroke sensor as shown in Patent Document 2, there is no risk of damage to the sensor, and a sensor protective cover is not required.

  However, the built-in sensor makes the cylinder itself expensive, and it is disadvantageous in terms of cost for a machine that performs only the original excavation work such as an excavator and may not be used as a crane at all. Moreover, since it is a built-in type, it cannot be retrofitted to an existing machine (cylinder).

  Therefore, the present invention provides a work machine that can be easily installed by retrofitting in a state where the angle detection sensor can be protected from earth and sand by a cover.

  According to the first aspect of the present invention, a working device is mounted on the machine body, and the working device is configured so that the coupled two members rotate relative to each other by a hydraulic cylinder to perform bending and stretching operations. In a working machine provided with a cylinder protection cover that slides integrally with the piston rod to protect the cylinder, a stroke sensor that detects the slide stroke of the cylinder protection cover as a stroke of the hydraulic cylinder is provided. The movable part provided inside the cylinder protective cover so as to be able to move integrally with the cover, and the movement amount of the movable part so as to be detected while being covered from the outside by the cylinder protective cover. It consists of a sensor main body provided in a cylinder tube of a hydraulic cylinder.

  According to a second aspect of the present invention, in the configuration of the first aspect, an upper swing body is mounted on the lower traveling body so as to be pivotable about a vertical axis to constitute a machine body, and the upper swing body includes a boom and an arm. A working device equipped with a bucket is mounted, and a movable portion of a stroke sensor is provided inside a cylinder protective cover provided on a boom cylinder for raising and lowering the boom, and a sensor main body is provided on a cylinder tube.

  According to a third aspect of the present invention, in the configuration of the first or second aspect, one end of a wire is fastened to the inside of the cylinder protective cover to form a movable portion, and the amount of movement of the wire is converted into an electric signal as the amount of movement of the movable portion A sensor body to be converted is provided on the cylinder tube to constitute a stroke sensor.

  According to a fourth aspect of the present invention, in the configuration of the first or second aspect, a rack gear serving as a movable portion is provided inside the cylinder protective cover, and the sensor main body that converts the amount of rotation of the pinion meshing with the rack gear into an electric signal is a cylinder. A stroke sensor is provided on the tube.

  According to a fifth aspect of the present invention, in the configuration of the first or second aspect, a non-contact type sensor main body for detecting a moving amount of the detected body, wherein a detected body as a movable portion is provided inside the cylinder protective cover. Is provided on the cylinder tube to constitute a stroke sensor.

  According to the present invention, the movable portion of the stroke sensor is provided inside the cylinder protective cover that protects the hydraulic cylinder (the boom cylinder of the hydraulic excavator in claim 2), and the sensor main body is provided in the cylinder tube. The stroke (the angle of the member driven by the cylinder. The boom angle in claim 2) is detected, that is, the cylinder protection cover is used for both the protection of the cylinder and the protection of the stroke sensor. It can be installed at a low cost without being added with a sensor-specific cover in a state where it can be protected from earth and sand.

  In addition, the cylinder is much cheaper than when using a sensor built-in cylinder, and can be easily retrofitted to existing machines.

  An embodiment of the present invention will be described with reference to FIGS.

  In the following embodiments, a case where a hydraulic excavator is applied and a stroke of the boom cylinder 6 for raising and lowering the boom 3 is detected is illustrated. Moreover, in the following embodiment, the same part as FIG. 8, 9 is attached | subjected and shown, and the duplication description is abbreviate | omitted.

1st Embodiment (refer FIGS. 1-3)
A cylinder protective cover 16 is provided outside the boom cylinder 6.

  Like the conventional cylinder protection cover 15 (FIG. 9), one end of the cylinder protection cover 16 is fixed to the tip of the piston rod 6a so as to cover the outer half of the piston rod 6a, and is integrated with the piston rod 6a. Slide to protect the rod 6a over the entire expansion / contraction range. FIG. 2A shows a cylinder extended state, and FIG. 2B shows a reduced state.

  In the first embodiment, the wire type stroke sensor 17 is provided in a state of being protected from the outside by the cylinder protection cover 16.

  That is, one end of the wire 18 is fixed to the inner upper part of the cylinder protective cover 16, and the movement amount of the wire fixing part 19 as a movable part is detected by the sensor main body 20 via the wire 18. Yes.

  The sensor main body 20 includes a wire reel 21 that winds the wire 18, and a signal converter (for example, a potentiometer) 22 that converts the amount of wire wound around the wire reel 21 into an electrical signal. It is installed on the upper part of the cylinder tube 6b that is always covered.

  In this configuration, when the boom cylinder 6 expands and contracts, the wire fastening portion 19 moves integrally with the piston rod 6a and the wire 18 is pulled, and this wire movement amount is the movement amount of the cylinder protective cover 16, that is, the boom cylinder 6 This is detected by the sensor body 20 as a stroke.

  This detection signal is input to a controller (not shown), and the ground angle of the boom 3 for calculating the load at the time of crane work is calculated from the detected value.

  As described above, the stroke sensor 17 is protected by the cylinder protective cover 16 for protecting the boom cylinder 6, that is, the cylinder protective cover 16 is also used as a protective cover for the stroke sensor 17. This eliminates the need to add a sensor-specific cover while ensuring protection from earth and sand.

  For this reason, since the dedicated cover can be omitted, the cost for installing the sensor can be reduced, and even a small machine such as a mini excavator having a small space can be easily installed.

  Further, the cylinder 6 is far less expensive than a built-in type in which a sensor is incorporated in the cylinder 6 itself, and can be easily retrofitted to an existing machine.

Second and third embodiments (see FIGS. 4 to 7)
In the second embodiment, a rack gear type stroke sensor 23 is used as shown in FIGS.

  The stroke sensor 23 includes a rack gear 24 as a movable portion provided in the cover length direction inside the cylinder protective cover 16, a pinion 25 that meshes with the rack gear 24 and rotates, and a rotation amount of the pinion 25. A sensor main body 27 is constituted by a converter (for example, a potentiometer) 26 that converts the electric signal.

  Similar to the first embodiment, the sensor main body 27 is installed on the upper part of the cylinder tube 6b that is always covered by the cylinder protective cover 16, and the movement amount of the rack gear 24 (= the movement amount of the cylinder protective cover 16) is the sensor main body. It is detected as a cylinder stroke by the unit 27.

  In the third embodiment, a non-contact type stroke sensor 28 is used as shown in FIGS.

  The stroke sensor 28 is provided on the inner side of the cylinder protection cover 16 in the length direction of the cover as a movable body 29 (for example, a strip-shaped sheet with scales) 29 and an upper portion of the cylinder tube 6a. It comprises an optical (or electromagnetic) sensor main body 30, and the amount of movement of the detected object 28 is detected by the sensor main body 30 as a cylinder stroke.

  According to both the second and third embodiments, basically the same operational effects as the first embodiment can be obtained.

  By the way, although the case where the stroke sensor was provided in the boom cylinder 6 was illustrated in the said embodiment, this invention is applicable similarly to the above also when providing a stroke sensor in the arm cylinder 7. FIG.

  The present invention is particularly suitable for a hydraulic excavator having a crane function, but can also be applied to other work machines having a crane function.

It is a side view which shows 1st Embodiment of this invention. (a) and (b) are the partially expanded views of the expansion state and contraction state of the boom cylinder in FIG. It is the III-III line expanded sectional view of Fig.2 (a). FIG. 4 is a view corresponding to FIG. 3 showing a second embodiment of the present invention. It is the VV line expanded sectional view of FIG. FIG. 6 is a view corresponding to FIG. 3 showing a third embodiment of the present invention. It is the VII-VII line expanded sectional view of FIG. It is a schematic side view of a hydraulic excavator. It is a partial enlarged view of the working device in the shovel.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lower traveling body 2 Upper revolving body A Work apparatus 3 Boom 4 Arm 5 Bucket 6 Boom cylinder 16 Cylinder protective cover 17 Stroke sensor 18 Wire 19 Wire fixing part 20 as a movable part 20 Sensor main part 21 Wire constituting the sensor main part Reel 22 Same as above, Signal converter 23 Stroke sensor 24 Rack as movable part of stroke sensor 27 Sensor body part 25 Pinion constituting sensor body part 26 Same as above Signal converter 28 Stroke sensor 29 Detected as movable part of stroke sensor Body 30 Sensor body

Claims (5)

  A working device is mounted on the machine body, and the working device is configured so that the coupled two members rotate relative to each other by a hydraulic cylinder to bend and extend, and slides integrally with the piston rod on the hydraulic cylinder. In a work machine provided with a cylinder protection cover that operates to protect the cylinder, a stroke sensor that detects a slide stroke of the cylinder protection cover as a stroke of the hydraulic cylinder is provided. Provided on the cylinder tube of the hydraulic cylinder so that the movable part provided inside can move integrally with the cover and the amount of movement of the movable part detected from the outside with the cylinder protective cover A working machine comprising: a sensor main body portion provided.   An upper swing body is mounted on the lower traveling body so as to be rotatable about the vertical axis to constitute a machine main body, and an operating device including a boom, an arm and a bucket is mounted on the upper swing body, and the boom is raised and lowered. 2. The work machine according to claim 1, wherein a movable portion of the stroke sensor is provided inside a cylinder protective cover provided on the boom cylinder to be operated, and a sensor main body is provided on the cylinder tube.   One end of the wire is fixed inside the cylinder protective cover to be a movable part, and a sensor body that converts the movement amount of the wire into an electric signal as the movement amount of the movable part is provided in the cylinder tube, thereby constituting a stroke sensor The work machine according to claim 1 or 2, wherein   A rack gear is provided as a movable part inside the cylinder protective cover, and a sensor body for converting the amount of rotation of the pinion meshing with the rack gear into an electric signal is provided on the cylinder tube to constitute a stroke sensor. The work machine according to claim 1 or 2.   A detection object as a movable part is provided inside the cylinder protective cover, and a non-contact type sensor body for detecting the amount of movement of the detection object is provided in the cylinder tube to constitute a stroke sensor. The work machine according to claim 1 or 2.

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