Rotation angle measuring device for the upper rotating body of construction machinery

Abstract

The present invention provides a slewing angle measuring device for the upper slewing body of construction machinery that can accurately measure the slewing angle of the upper slewing body without the sensor's measurement reference point shifting. [Solution] An encoder fixing bracket 18b is attached to the door handle of the upper rotating body 16, and a wire encoder 18 is attached to the encoder fixing bracket 18b. Meanwhile, a pole fixing bracket 19a is attached to the inside of the travel frame of the lower traveling body 17, and a wire fixing pole 19 is attached to the pole fixing bracket 19a. A wire 18a is extended from the wire encoder 18 and connected to the wire fixing pole 19. The rotation angle of the upper rotating body 16 is calculated based on the length of the wire 18a stretched between the wire encoder 18 and the wire fixing pole 19.

Description

[Technical Field]

[0001] The present invention relates to a device for measuring the rotation angle of an upper rotating body for construction machinery. More specifically, the present invention relates to a device for measuring the rotation angle of an upper rotating body for construction machinery that can accurately measure the rotation angle of the upper rotating body without the measurement reference point of the sensor shifting. [Background technology]

[0002] Hydraulic excavators such as backhoes are composed of an upper rotating body to which the boom, arm, bucket, etc. are attached, and a lower traveling body to which the crawler equipment, etc. are attached. A slewing bearing is installed between the upper rotating body and the lower rotating body, and the upper rotating body is configured to rotate relative to the lower traveling body.

[0003] Figure 5 is an explanatory diagram illustrating the schematic mechanism of a slewing bearing. The inner ring is directly connected to the lower running body, and the outer ring is directly connected to the upper running body. An internal gear is formed along the circumferential direction on the inner surface of the inner ring, and this internal gear meshes with a small gear of a slewing motor fixed to the upper slewing body. Therefore, when the slewing motor rotates, the upper slewing body rotates relative to the lower running body.

[0004] Since the rotation radius R1 of the upper rotating body and the rotation radius R2 of the rotating motor are known, the rotation angle θ1 of the upper rotating body is equal to the value obtained by multiplying the rotation angle θ2 of the rotating motor by the ratio of the radii of rotation radius R1 to the rotation radius R2 (= R2 / R1). In other words, if the rotation angle θ2 of the rotating motor can be measured, the rotation angle θ1 of the upper rotating body can be automatically determined.

[0005] However, since a hydraulic hose is connected to the slewing motor and a small gear is connected to the end of the rotating shaft, it is generally not easy to measure the rotation angle θ2 of the slewing motor via the rotating shaft using a rotary encoder or the like.

[0006] By the way, in a swivel joint mechanism that supplies hydraulic oil (hydraulic pressure) to the traveling motor of the lower traveling body, a magnetic sensor is attached to a member that rotates integrally with the upper slewing body, and a magnet is attached to a member that rotates integrally with the lower traveling body. It is known an invention related to a method for measuring the slewing angle of the upper slewing body using a swivel joint mechanism, in which the slewing angle of the upper slewing body can be measured based on the magnetic flux density detected by the magnetic sensor (for example, see Patent Document 1).

[0007] Also, as another method for measuring the slewing angle of the upper slewing body, an angular velocity sensor (IMU sensor such as a gyro sensor) and a GNSS receiving antenna are respectively attached to the upper slewing body. First, the predicted slewing angle obtained by successively adding (integrating) the values obtained by multiplying the measured value of the angular velocity sensor by the time width from the measurement start time to the measurement end time, and then, the reference slewing angle based on the azimuth information of the reference position obtained from the GNSS receiving antenna are respectively obtained. Then, the ratio (correction coefficient) of the predicted slewing angle to the reference slewing angle is obtained, and by multiplying the measured value of the angular velocity sensor by the correction coefficient, it is possible to measure the slewing angle of the upper slewing body. An invention related to a method for measuring the slewing angle of the upper slewing body using an angular velocity sensor and GNSS (Global Navigation Satellite System) is known (for example, see Patent Document 2).

[0008] Also, as another method for measuring the slewing angle of the upper slewing body, a transmitter that emits radio waves is attached to the lower traveling body, and a plurality of receivers that receive radio waves are attached to the upper slewing body. It is known an invention related to a method for measuring the slewing angle of the upper slewing body using the received radio wave intensity, in which the slewing angle of the upper slewing body can be calculated based on the intensity of the radio waves received by each of the plurality of receivers (for example, see Patent Document 3).

Prior Art Documents

Patent Documents

[0009]

Patent Document 1

Patent Document 2

[0010] The physical quantity to be measured in the method for measuring the rotation angle described in Patent Document 1 is magnetic flux density. The physical quantity to be measured in the method for measuring the rotation angle described in Patent Document 2 is centrifugal force when an object rotates. The physical quantity to be measured in the method for measuring the rotation angle described in Patent Document 3 is the intensity of radio waves.

[0011] Therefore, when determining an angle from a physical quantity being measured, at least two processing steps are required: (1) converting the physical quantity to be measured into an electrical signal via a sensor, and (2) substituting that electrical signal into a calibration formula stored in a computer to convert it into an angle. However, when measurements are taken outdoors, noise can cause the measurement reference point of the sensor to shift in processing step (1), a phenomenon known as drift. When drift occurs, the error caused by the drift will be added to the true measured value.

[0012] In particular, in a measurement method that calculates the turning angle by sequentially adding (integrating) the values ​​obtained by multiplying the measured value of the angular velocity sensor by a time width from the start time to the end time of measurement, as described in Patent Document 2 above, errors caused by the drift phenomenon are also added sequentially from the start time to the end time of measurement, and in the worst case, the measured turning angle may deviate significantly from the actual turning angle.

[0013] Therefore, the present invention has been made in view of the problems of the prior art described above, and its purpose is to provide a slewing angle measuring device for the upper slewing body of construction machinery that can accurately measure the slewing angle of the upper slewing body without the measurement reference point of the sensor shifting. [Means for solving the problem]

[0014] To achieve the above objective, the present invention provides a slewing angle measuring device for an upper slewing body of a construction machine, comprising a lower base body (17) that serves as a base and an upper slewing body (16) that is rotatably arranged on the lower base body (17). The device measures the slewing angle (θ6) of the upper slewing body (16) in the vertical direction, and is characterized in that the slewing angle (θ6) is measured based on the length (L) of a wire (18a) stretched between a wire encoder (18) attached to the upper slewing body (16) and a rod-shaped wire fixing pole (19) installed at a position away from the upper slewing body (16).

[0015] In the above configuration, one end of the wire (18a) is attached to the upper rotating body (16), and the other end is installed at a position away from the upper rotating body (16). Therefore, the length (L) of the wire (18a) corresponds one-to-one with the rotation angle (θ6) of the upper rotating body (16).

[0016] Furthermore, the wire encoder (18) that measures the length (L) of the wire (18a) measures the rotation angle of the wire winder by counting the binarized signal (digital signal of 1 or 0) when the measurement light passes through the slit window ("1") / is blocked ("0"). Also, since the slit with the window is directly connected to the rotation axis of the wire winder, the slit remains stationary while the wire (18a) is stationary. In other words, as long as the upper rotating body (16) is stationary, the measurement reference point of the wire encoder (18) will not drift. Thus, since the measured length (L) of the wire (18a) is always constant as long as the upper rotating body (16) is stationary, the rotation angle measuring device according to the present invention can accurately measure the rotation angle of the upper rotating body even when the construction machine is placed in a noisy environment.

[0017] A second feature of the slewing angle measuring device for the upper slewing body of construction machinery according to the present invention is that the upper slewing body (16) has a recess (70a) formed on its surface into which the wire (18a) fits, and the back surface has a flexible belt (70) that can be detachably attached to the upper slewing body (16).

[0018] In the above configuration, the wire (18a) moves along the recess (70a) of the flexible belt (70), thus restricting the winding direction of the wire (18a) to a fixed direction. As a result, the length (L) of the wire (18a) does not fluctuate with respect to the rotation angle (θ6) of the upper rotating body (16). This makes it possible to accurately measure the rotation angle.

[0019] A third feature of the slewing angle measuring device for the upper slewing body of construction machinery according to the present invention is that the wire fixing pole (19) is installed on the lower base body (17).

[0020] In the above configuration, the wire fixing pole (19) can be installed near the upper rotating body (16). This relaxes the requirements for the total length of the wire (18a) and expands the availability of the wire encoder (18).

[0021] A fourth feature of the slewing angle measuring device for the upper slewing body of a construction machine according to the present invention is that the lower base body (17) has a means for traveling.

[0022] In the above configuration, the crawler device or other means of travel such as wheels will provide space for attaching the bracket device (19a) of the wire fixing pole (19). Therefore, it becomes possible to install the wire fixing pole (19) near the upper rotating body (16). This relaxes the requirements for the total length of the wire (18a) and expands the availability of the wire encoder (18).

[0023] A fifth feature of the rotation angle measuring device for the upper rotating body of a construction machine according to the present invention is that the wire (18a) is covered.

[0024] In the above configuration, the upper rotating body (16) will not be damaged by the wire (18a) during measurement.

[0025] A sixth feature of the rotation angle measuring device for the upper rotating body of a construction machine according to the present invention is that the wire (18a) is non-metallic.

[0026] In the above configuration, the upper rotating body (16) will not be damaged by the wire (18a) during measurement.

[0027] A seventh feature of the slewing angle measuring device for the upper slewing body of a construction machine according to the present invention is that the upper slewing body (16) has a plurality of roller bodies (71) on its surface into which the wire (18a) is fitted.

[0028] In the above configuration, when the upper rotating body (16) rotates, it is possible to reduce the sliding resistance between the wire (18a) and the upper rotating body (16) while applying appropriate tension to the wire (18a). This allows the wire (18a) to be smoothly wrapped along the surface of the upper rotating body (16), and enables accurate measurement of the rotation angle of the upper rotating body (16). [Effects of the Invention]

[0029] According to the slewing angle measuring device for the upper slewing body of construction machinery of the present invention, the slewing angle of the upper slewing body can be measured with high accuracy without the measurement reference point of the sensor shifting. [Brief explanation of the drawing]

[0030] [Figure 1] This is a forward perspective explanatory diagram showing a slewing angle measuring device for the upper slewing body of a construction machine according to one embodiment of the present invention. [Figure 2] This is a rearward perspective explanatory diagram showing a slewing angle measuring device for the upper slewing body of a construction machine according to one embodiment of the present invention. [Figure 3]This is an explanatory diagram illustrating the measurement principle for detecting the rotation angle of the upper rotating body using a wire encoder. [Figure 4] This is an explanatory diagram showing how to calculate the turning angle from the wire length when the wire is in a bent state. [Figure 5] This is an explanatory diagram showing the schematic mechanism of a slewing bearing. [Figure 6] This is an explanatory diagram showing a wire body that regulates the winding direction of the wire. [Modes for carrying out the invention]

[0031] Embodiments of the present invention will be described in detail below with reference to the attached drawings.

[0032] Figure 1-2 is an explanatory diagram showing a rotation angle measuring device 100 for the upper rotating body of a construction machine according to one embodiment of the present invention. Figure 1 is a forward perspective explanatory diagram, and Figure 2 is a rear perspective explanatory diagram. For the sake of explanation, the construction machine is also shown in the diagram.

[0033] This slewing angle measuring device 100 for the upper slewing body of construction machinery is configured to measure the length L of the wire 18a using a wire encoder 18 and to calculate the slewing angle θ6 of the upper slewing body 16 based on the length L of the wire 18a.

[0034] The wire encoder 18 measures the rotation angle of the wire winder (not shown) by counting the binarized signal (digital signal of 1 or 0) when the measurement light passes through ("1") / is blocked ("0") the window of the slit (not shown). Since the slit is directly connected to the rotation axis of the wire winder, the slit remains stationary as long as the wire 18a remains stationary. In other words, as long as the upper rotating body 16 is stationary, the slit also remains stationary, so the measurement reference point of the wire encoder 18 does not drift. Thus, the length L of the wire 18a corresponds one-to-one with the rotation angle θ6 of the upper rotating body 16, and the rotation angle θ6 of the upper rotating body 16 can be uniquely and accurately determined from the length L of the wire 18a.

[0035] The slewing angle measuring device 100 for the upper slewing body of construction machinery comprises a wire encoder 18 attached to the upper slewing body 16, an encoder fixing bracket 18a for attaching the wire encoder 18, a wire fixing pole 19 attached to the lower traveling body 17, a pole fixing bracket 19a for attaching the wire fixing pole 19, and a magnetic tape 70 that restricts the winding direction of the wire 18a around the upper slewing body 16 to a fixed direction.

[0036] The wire encoder 18 is attached to the upper swivel body 16 by an encoder fixing bracket 18b. The encoder fixing bracket 18b is fixed to the door handle of the upper swivel body 16 by a U-bolt.

[0037] The wire fixing pole 19 is attached to the lower running body 17 by a pole fixing bracket 19a. The pole fixing bracket 19a is fixed to the inside of the running body frame of the lower running body 17 by bolts. The pole fixing bracket 19a is provided symmetrically at four locations on the inside of the running body frame of the lower running body 17.

[0038] The magnetic tape 70 is attached to the upper rotating body 16 by magnetic force in a way that allows it to be easily attached and detached. A V-shaped groove 70a is formed on the surface along its longitudinal direction. However, the groove 70a only needs to accommodate the wire 18a, and its cross-sectional shape is not particularly important.

[0039] Figure 3 is an explanatory diagram illustrating the measurement principle for detecting the rotation angle θ6 of the upper rotating body 16 using a wire encoder 18. Figure 3(a) shows the initial state of the rotation angle θ6. Figure 3(b) shows the rotation angle θ6 when the upper rotating body 16 rotates counterclockwise.

[0040] As shown in Fig. 3(a), a wire encoder 18 is attached to the body of the upper swinging body 16. The wire 18a extending from the wire encoder 18 is fastened to the wire fixing pole 19. The wire fixing pole 19 may be located at a position that does not affect the swinging operation of the upper swinging body 16. For example, it is fixed to the lower traveling body 17 (Fig. 1-2). As a result, the wire encoder 18 is a moving point that swings together with the upper swinging body 16, while the wire fixing pole 19 is a fixed point (stationary point) that does not swing together with the upper swinging body 16.

[0041] The distance a between the turning center C6 and the wire encoder 18 is always a constant value. Also, the distance b between the turning center C6 and the wire fixing pole 19 is always a constant value. Further, the distance d between the corner B and the wire encoder 18 is always a constant value.

[0042] Let the angle θ0 formed by the wire encoder 18, the turning center C6, and the wire fixing pole 19, and let the initial wire length be L0. In this case, the angle θ0 is calculated as shown in the following formula 1 using the cosine theorem. Cosine theorem: L0 2 =a 2 +b 2 -2ab×COSθ0 Formula 1: θ0 = COS -1 {(a 2 +b 2 -L0 2 ) / 2ab}

[0043] As shown in Fig. 3(b), when the wire length is L, the turning angle θ6 is calculated as shown in the following formula 2 using the cosine theorem. Cosine theorem: L 2 =a 2 +b 2 -2ab×COS(θ6 + θ0) Formula 2: θ6 = COS -1 {(a 2 +b 2 -L 2 ) / 2ab}-θ0

[0044] Note that equation 2 above is valid only when the wire 18a is in a straight state. When the wire 18a is in a broken wire state (Figure 4), the turning angle θ6 cannot be calculated using equation 2 above. The method for calculating the turning angle θ6 from the wire length L when the wire 18a is in a broken wire state is described below.

[0045] Figure 4 is an explanatory diagram showing how to calculate the rotation angle θ6 from the wire length L when the wire 18a is in a broken wire state. Figure 4(a) shows how to calculate the rotation angle θ6 when the wire 18a is in a broken wire state once. Figure 4(b) shows how to calculate the rotation angle θ6 when the wire 18a is in a broken wire state twice.

[0046] As shown in Figure 4(a), the rotation angle θ6 is composed of angle θ6-1 and angle θ6-2. Angle θ6-1 can be calculated by substituting a with c and L with Ld in equation 2 above. Equation 3: θ6-1=COS -1 [{c 2 +b 2 -(Ld) 2} / 2cb]-θ0

[0047] On the other hand, the angle θ6-2 can be calculated using the Law of Cosines for triangle A·B·C6 as shown in equation 4 below. Equation 4: θ6-2=COS -1 {(a 2 +c 2 -d 2 ) / 2ca}

[0048] Therefore, from equations 3 and 4, the rotation angle θ6 is calculated as shown in equation 5 below. Equation 5: θ6 = θ6 - 2 + θ6 - 1 = COS -1 {(a 2 +c 2 -d 2 ) / 2ca}+COS -1 [{c 2 +b 2 -(Ld) 2} / 2cb]-θ0

[0049] As shown in Figure 4(b), the rotation angle θ6 is composed of angles θ6-1', θ6-2, and θ6-3. Angle θ6-1' can be calculated by substituting c with e and Ld with Ldf in equation 3 above. Equation 6: θ6-1'=COS -1 [{e 2 +b 2 -(Ldf) 2} / 2eb]-θ0

[0050] On the other hand, the angle θ6-2 has already been calculated using equation 4 above.

[0051] Furthermore, the angle θ6-3 is calculated using the Law of Cosines for triangle B·C·C6 as shown in equation 7 below. Equation 7: θ6-3=COS -1 {(c 2 +e 2 -f 2 ) / 2ce}

[0052] Therefore, from equations 3 and 4, the rotation angle θ6 is calculated as shown in equation 8 below. Formula 8: θ6=θ6-3+θ6-2+θ6-1'=COS -1 {(c 2 +e 2 -f 2 ) / 2ce}+COS -1 {(a 2 +c 2 -d 2 ) / 2ca}+COS -1 [{e 2 +b 2 -(Ldf) 2} / 2eb]-θ0

[0053] Although the derivation process is omitted, the rotation angle θ6 when the wire 18a is wound around the upper rotating body 16 in a bent state three times is calculated as shown in equation 9 below. Equation 9: θ6=θ6-4+θ6-3+θ6-2+θ6-1”=COS -1 {(c 2 +e 2 -g2 ) / 2ce}+COS -1 {(c 2 +e 2 -f 2 ) / 2ce+COS -1 {(a 2 +c 2 -d 2 ) / 2ca}+COS -1 [{c 2 +b 2 -(Ldfg) 2} / 2bc]-θ0

[0054] As can be seen from equations 2, 5, 8, and 9 above, the only value measured when measuring the rotation angle θ6 is the wire length L. Since the wire length L can be accurately measured by the wire encoder 18 and the wire fixing pole 19, the rotation angle θ6 can be accurately calculated by using the wire encoder 18 and the wire fixing pole 19.

[0055] While the slewing angle measuring device 100 for the upper slewing body of a construction machine according to one embodiment of the present invention has been described with reference to the drawings, the present invention is not limited to the above embodiment. That is, various modifications and changes can be made as long as they do not depart from the technical scope of the present invention. For example, the construction machine to which the present invention is applied may be a stationary construction machine. Also, the detachable flexible belt that restricts the winding direction of the wire 18a may be a bellows type instead of a magnetic type. Furthermore, the cross-sectional shape of the groove 70a may be U-shaped. Moreover, the wire 18a may be made of a non-metallic material, such as resin.

[0056] Alternatively, instead of the detachable flexible belt that restricts the winding direction of the wire 18a, roller bodies 71 (Figure 6) can be used. In this case, multiple roller bodies 71 will be fixed to the surface of the upper swivel body 16 at intervals using bolts 71f and nuts 71e. [Explanation of Symbols]

[0057] 16 Upper rotating body 17 Lower running body (lower base body) 18 Wire Encoders 18a wire 18b Encoder mounting bracket 19. Pole for securing wires 19b Pole mounting bracket 70 Magnetic Tape (Flexible Belt) 70a Groove (recess) 71 Roller Body 71a Roller 71b Roller shaft 71c roller bracket 71d Bracket Base 71e Nut 71f Bolt θ6 rotation angle

Claims

1. A measuring device (100) for measuring the rotation angle (θ6) of the upper rotation body (16) of a construction machine comprising a lower base body (17) that serves as a base and an upper rotation body (16) that is rotatably arranged on the lower base body (17), The rotation angle (θ6) of the upper rotating body (16) in the vertical direction is measured based on the length (L) of the wire (18a) stretched between a wire encoder (18) attached to the upper rotating body (16) and a rod-shaped wire fixing pole (19) installed at a distance from the upper rotating body (16). A device for measuring the rotation angle of an upper rotating body for construction machinery, characterized by the above features.

2. In the slewing angle measuring device for the upper slewing body of a construction machine according to claim 1, The upper rotating body (16) has a recess (70a) formed on its surface into which the wire (18a) fits, and its back surface has a flexible belt (70) that can be detachably attached to the upper rotating body (16). A device for measuring the rotation angle of an upper rotating body for construction machinery, characterized by the above features.

3. In the slewing angle measuring device for the upper slewing body of a construction machine according to claim 1, The wire fixing pole (19) is installed on the lower base body (17). A device for measuring the rotation angle of an upper rotating body for construction machinery, characterized by the above features.

4. In the slewing angle measuring device for the upper slewing body of a construction machine according to claim 1, The lower base body (17) has a means of travel. A device for measuring the rotation angle of an upper rotating body for construction machinery, characterized by the above features.

5. In the slewing angle measuring device for the upper slewing body of a construction machine according to claim 1, The wire (18a) is covered. A device for measuring the rotation angle of an upper rotating body for construction machinery, characterized by the above features.

6. In the slewing angle measuring device for the upper slewing body of a construction machine according to claim 1, The wire (18a) is nonmetallic. A device for measuring the rotation angle of an upper rotating body for construction machinery, characterized by the above features.

7. In the slewing angle measuring device for the upper slewing body of a construction machine according to claim 1, The upper rotating body (16) has a plurality of roller bodies (71) on its surface into which the wire (18a) is fitted. A device for measuring the rotation angle of an upper rotating body for construction machinery, characterized by the above features.

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