JP5545865B2 - Rotary sensor mounting structure - Google Patents

Description

The present invention relates to a rotary sensor mounting structure for detecting a rotation angle (rotation amount) of a lift arm with respect to a hydraulic cylinder case .

Conventionally, a rotary sensor for detecting a rotation angle of a lift arm with respect to a hydraulic cylinder case has been known. For example, as described in Patent Document 1. The rotary sensor disclosed in Patent Document 1 is fixed to a hydraulic cylinder case , a sensor shaft that is mounted so that the axis of rotation of the lift arm coincides with the axis, and rotates integrally with the lift arm. A sensor main body for detecting a rotation angle of the lift arm with respect to the hydraulic cylinder case via the sensor shaft. In the mounting structure of the rotary sensor having such a configuration, in order to obtain an accurate detection result, it is necessary to arrange the sensor shaft and the rotary shaft on a straight line with high accuracy.

Therefore, in the rotary sensor mounting structure described in Patent Document 1, a seat, a bracket, or the like is interposed between the hydraulic cylinder case and the sensor body, and the spigot portions formed at a plurality of locations of the bracket are used. Thus, the sensor main body can be fixed to the hydraulic cylinder case in a state in which the sensor shaft and the rotation shaft are aligned with each other. However, when the mounting structure described in Patent Document 1 is adopted, it is necessary to secure a space for arranging the seats, brackets, and the like. Therefore, the axial direction of the sensor shaft (hereinafter referred to as “sensor axial direction”) is described. )) Is disadvantageous in that it cannot be made compact.

On the other hand, Patent Document 2 discloses a mounting structure for a rotary sensor that can make the dimension in the sensor axial direction compact. Specifically, the projection is provided at two places different from the rotation axis of the lift arm , and the plate on which the two notches that can contact the projection are formed is fixed to the rotation axis so as not to be relatively rotatable. Yes. In the case of such a configuration, the bracket or the like in which the spigot portion is formed is unnecessary, so that the interval between the arrangement of the rotation shaft and the sensor shaft in the sensor axis direction can be set narrower than before. However, when the mounting structure described in Patent Document 2 is adopted, it is necessary to mount the rotary sensor to the hydraulic cylinder case in a state where the notch of the plate is pressed against the protrusion, so that it is difficult to adjust the mounting position. It was disadvantageous in some ways. Specifically, it is necessary to fix the sensor body to the hydraulic cylinder case with the other hand while holding the plate by hand etc. and aligning the mutual positions of the sensor shaft and the rotary shaft. It was over. Furthermore, when such an attachment structure is employed, a spring or the like is required separately to hold the plate notch against the projection, which is disadvantageous in that the number of parts increases.

JP-A-9-68420 JP 2008-82875 A

The present invention has been made in view of the situation as described above, and the size in the sensor axial direction can be made compact, and the rotary sensor can be easily attached to the lift arm and the hydraulic cylinder case . In addition, a rotation sensor mounting structure that can be realized with a small number of parts is proposed.

The rotary sensor according to claim 1 , wherein the lift arm is rotatably supported with respect to the hydraulic cylinder case, and is fixed to the rotation axis of the lift arm and the hydraulic cylinder case via a mounting bracket. In a rotary sensor mounting structure for detecting a rotation angle of the lift arm with respect to the hydraulic cylinder case, the rotation axis of the lift arm rotating shaft being mounted so that the axis of the sensor shaft is the same axis. Two pins projecting from the end of the lift arm toward the rotary sensor side are extended in a direction parallel to the rotational axis at a position away from the center, and the two pins are In the rotating shaft, two insertion holes are drilled, and the pin is fitted and fixed in the insertion hole, and the shaft-shaped member extends from the end of the rotating shaft of the lift arm to the rotary sensor side. As The sensor shaft is provided with a plate which is a substantially rectangular plate-like member in which two holes are formed on the plate surface facing the lift arm so as to match the two pins. The plate surface facing the rotation axis of the plate is formed with an insertion hole for the sensor shaft at the center of the plate, and other than the insertion hole at the center. The two holes are opened as positions and shapes corresponding to the pins, and the tip portions of the two pins are inserted through the two holes .

According to a second aspect of the present invention, in the rotary sensor mounting structure according to the first aspect, the sensor shaft is configured as a screw shaft in which a screw is formed on an outer peripheral surface, and an outer periphery of a tip end portion of the sensor shaft on the lift arm side. In this case, two planes parallel to the shaft center are cut to form a flat portion, and a through hole is formed in the center of the plate surface of the plate in accordance with the cross-sectional shape of the tip of the sensor shaft. The tip of the shaft can be inserted, and in the state where the tip of the sensor shaft is fitted in the through hole of the plate, a nut is screwed into the tip of the sensor shaft, and the plate is fixed to the sensor shaft. is there.

The present invention is advantageous in that the dimensions in the sensor axis direction can be made compact, the attachment to the lift arm and the hydraulic cylinder case can be easily performed, and the sensor can be realized with a small number of parts.

It is a left view which shows the whole structure of the tractor to which the attachment structure of the rotation type sensor which concerns on one Embodiment of this invention is applied. It is a left view which shows the attachment structure of the rotation type sensor which concerns on one Embodiment of this invention. It is a rear view which shows the attachment structure of the rotation type sensor which concerns on one Embodiment of this invention. It is a rear view which shows the attachment structure of the rotation type sensor which concerns on another one Embodiment of this invention. It is a disassembled perspective view which shows the fixing method to the sensor axis | shaft of the plate in the attachment structure of the rotation type sensor which concerns on another one Embodiment of this invention.

  First, an overall configuration of a tractor 1 to which a rotary sensor mounting structure according to an embodiment of the present invention is applied will be described with reference to FIG.

  The tractor 1 is a work vehicle capable of performing various operations by attaching a work device to the traveling machine body 10 as necessary. The tractor 1 of this embodiment is equipped with a rotary tiller 9 as a working device. A traveling machine body 10 of the tractor 1 is supported from below by front wheels 2 and 2 and rear wheels 3 and 3. A mission case 4 is provided at the rear of the traveling machine body 10 of the tractor 1. The transmission case 4 accommodates a transmission or the like for appropriately shifting the power obtained from the engine and transmitting it to each part. A hydraulic cylinder case 30 that houses a hydraulic cylinder is placed and fixed on the transmission case 4. The hydraulic cylinder case 30 supports the rotation base of the lift arm 60. When the hydraulic cylinder in the hydraulic cylinder case 30 is driven, the lift arm 60 can be rotated up and down around the rotation axis C (see FIGS. 2 and 3).

  A rotary tiller 9 is attached to the end (front end) of the lift arm 60 opposite to the rotating base via the link mechanism 5. By driving the hydraulic cylinder in the hydraulic cylinder case 30, the rotary tiller 9 is raised or lowered via the lift arm 60, the link mechanism 5, etc., and the height of the rotary tiller 9 with respect to the ground is adjusted. It is configured to be able to.

A rotary sensor 50 is attached to the side of the lift arm 60 and the hydraulic cylinder case 30 (left side in the present embodiment). The rotation type sensor 50 has a rotation shaft 61 (FIGS. 2 and 3) of the lift arm 60 by an attachment structure 80 (FIGS. 2 and 3) which is an embodiment of the “rotation type sensor attachment structure” according to the present invention. 3) and the hydraulic cylinder case 30. The lift arm 60 is fixed to the rotation shaft 61 so as not to rotate relative to the rotation shaft 61, and rotates integrally with the rotation shaft 61 about a rotation axis C corresponding to the axis of the rotation shaft 61. .

  With reference to FIG.2 and FIG.3, the structure of the rotation type sensor 50 is demonstrated. The rotation type sensor 50 is a sensor for detecting the rotation angle of the lift arm 60 with respect to the hydraulic cylinder case 30, and is constituted by, for example, a rotation type potentiometer. The rotary sensor 50 includes a sensor shaft 51 (see FIG. 3) and a sensor main body 52. However, the “rotary sensor” according to the present invention is not limited to a potentiometer, and may be a rotary encoder, for example.

  The sensor shaft 51 is a shaft-shaped member, and is provided so that one end portion (tip portion) protrudes from the sensor main body 52 toward the rotating shaft 61 side. The axis (axis) of the sensor shaft 51 coincides with the rotation axis C of the lift arm 60 (rotation shaft 61), that is, is mounted on the same axis, and will be described later. The lift arm 60 (the rotation shaft 61) is integrally rotated.

  The sensor main body 52 is the main body of the rotary sensor 50, and includes a detection unit. The detection unit in the sensor main body 52 can generate a signal corresponding to the rotation angle and extract the detection signal through a signal line (not shown). The sensor body 52 supports the sensor shaft 51 described above so as to be rotatable in the circumferential direction. The sensor body 52 is fixed to the hydraulic cylinder case 30 via the mounting bracket 41, the fixed plate 42, and the like.

  Specifically, the mounting bracket 41 is a member formed by bending a plate material into a crank shape, and has a plate surface portion 41a on one side and a plate surface portion 41b on the other side. The plate surface portion 41 a is disposed near the inside of the traveling aircraft body 10, and the plate surface portion 41 b is disposed near the outside of the traveling aircraft body 10. The plate surface portion 41a closer to the inside is fixed to the left side surface portion of the hydraulic cylinder case 30 by using bolts 43 or the like. The sensor main body 52 is fixed to the outer plate surface portion 41b via the fixed plate 42.

In addition, although the sensor main body 52 of this embodiment is being fixed to the hydraulic cylinder case 30 via the attachment bracket 41, the fixed plate 42, etc., this invention is not limited to this. In other words, the sensor body may be directly fixed to the hydraulic cylinder case, or may be indirectly fixed to the hydraulic cylinder case. For example, instead of the above configuration, the sensor main body 52 may be fixed to the mission case 4. That is, the sensor body may be fixed to a member that is stationary with respect to the hydraulic cylinder case when the lift arm rotates.

  With such a configuration, when the lift arm 60 is rotated with respect to the hydraulic cylinder case 30 by driving the hydraulic cylinder, the sensor shaft 51 rotates with respect to the sensor body 52, and the sensor shaft 51 is lifted. It rotates (rotates) by the same angle as the arm 60. Therefore, the angle detected by the detection unit of the sensor body 52 via the sensor shaft 51 is the rotation angle (detection result) of the lift arm 60 with respect to the hydraulic cylinder case 30. From the detection result of the rotary sensor 50, the height of the rotary tiller 9 with respect to the ground can be grasped. The detection result is fed back to the control device of the tractor 1 and used when correcting an error from a value set by an operation lever or the like. In this way, the tractor 1 adjusts the amount of rotation of the lift arm 60 with high accuracy.

  With reference to FIG.2 and FIG.3, the spring pin (roll pin) 81 * 81 and plate 82 with which the attachment structure 80 is provided are demonstrated in detail.

  The spring pins 81 and 81 are shaft-shaped members provided so as to protrude from the end portion (left end portion in the present embodiment) of the rotation shaft 61 of the lift arm 60 toward the rotary sensor 50 (sensor body 52). is there. The spring pin 81 is an embodiment of the “projection” according to the present invention. The spring pins 81 and 81 of the present embodiment are parallel to the rotation axis C from positions separated from the rotation axis C in the left side view of the rotation shaft 61, that is, from two places different from the rotation axis C. It projects (extends) toward the right direction. More specifically, the left end surface of the rotation shaft 61 is point-symmetric with respect to the rotation axis C in the left side view, that is, two distances from the rotation axis C that are equal to each other and 180 degrees out of phase. Insertion holes 61a and 61a are formed (drilled) at the positions, respectively. The spring pins 81 and 81 are fitted into the insertion holes 61a and 61a and fixed.

  The plate 82 is a substantially rectangular plate-shaped member. The central portion of the plate surface of the plate 82 is fixed (fixed) to the sensor shaft 51 so as not to be relatively rotatable. More specifically, an insertion hole is formed in the central portion of the plate 82, and the sensor shaft 51 is inserted into the insertion hole and fixed by welding, caulking, or the like. However, the fixing method is not limited to this.

  The pair of plate surfaces of the plate 82 form a surface perpendicular to the sensor shaft 51 direction. Two holes 82a and 82a are formed on the plate surface of the plate 82 facing the lift arm 60 (rotating shaft 61) in addition to the insertion hole at the center. The two holes 82a and 82a are formed in positions and shapes corresponding to the spring pins 81 and 81, respectively. That is, the holes 82a and 82a are located at point-symmetrical positions with respect to the center of the plate surface of the plate 82 in the left side view, that is, at two positions whose distances from the center of the insertion hole are equal and 180 degrees out of phase. Opened. The tips of the spring pins 81 and 81 can be inserted (penetrated) into the holes 82a and 82a.

  In the present embodiment, the spring pins 81 and 81 are provided at two locations around the rotation axis C, but the number of locations where the protrusions are provided is not limited to two. That is, the protrusions may be provided at three or more locations around the rotation axis C. In this case, the positions and shapes of the holes formed in the plate are also changed as appropriate according to the positions and shapes of the protrusions. For example, it is possible to adopt a configuration in which three protrusions and holes are provided, or two of the provided holes as a configuration in which two protrusions and four or six holes are provided. It is also possible to engage with the projection.

  With reference to FIG. 3, the procedure for attaching the rotary sensor 50 to the lift arm 60 (rotating shaft 61) and the hydraulic cylinder case 30 will be described.

The rotary sensor 50 is attached according to the following procedures (1) to (3).
(1) First, the rotary sensor 50 and the fixed plate 42 are fixed (assembled) to the mounting bracket 41 using bolts 44 and 44 or the like. Further, the plate 82 is fixed to the tip of the sensor shaft 51. Further, the spring pins 81 and 81 are fitted into the insertion holes 61 a and 61 a of the rotating shaft 61 and fixed.
(2) Subsequently, the holes 82a and 82a of the plate 82 are fitted to the spring pins 81 and 81 so that the rotation axis C and the axis of the sensor shaft 51 coincide with each other. Thereby, the sensor shaft 51 and the rotation shaft 61 of the lift arm 60 are engaged with each other so as not to be relatively rotatable. That is, the sensor shaft 51 and the lift arm 60 are in a state of rotating integrally with the rotation axis C as a fulcrum.
(3) Subsequently, the plate surface portion 41a closer to the inner side of the mounting bracket 41 is fixed to the left side surface portion of the hydraulic cylinder case 30 using bolts 43 or the like. At this time, since the mutual alignment of the sensor shaft 51 and the rotation axis C has already been performed in the process (2), the position of the plate surface portion 41a and the hydraulic cylinder case 30 can be easily adjusted. it can. Thus, the rotary sensor 50 can be attached with the rotational axis C and the axis of the sensor shaft 51 easily matched with high accuracy.

  As described above, the mounting structure 80 of the rotary sensor 50 in the present embodiment is supported by the lift arm 60 so as to be rotatable with respect to the hydraulic cylinder case 30, and the rotational axis C of the lift arm 60 and the hydraulic cylinder case 30. Attaching the rotary sensor 50 that detects the rotation angle of the lift arm 60 with respect to the hydraulic cylinder case 30 is attached so that the axis of the sensor shaft 51 of the rotary sensor 50 fixed to the same is the same axis. In the structure, the end of the lift arm 60 (strictly in the present embodiment, the rotational shaft 61) is located at a position separated from the rotational axis C of the lift arm 60 (strictly, the rotational shaft 61 in the present embodiment). A plurality of spring pins 81 and 81 projecting from the portion toward the rotary sensor 50 are provided, and a plurality of sensor pins 51 are provided on the plate surface facing the lift arm 60 (rotating shaft 61). A plate 82 in which a plurality of holes 82a and 82a are formed in accordance with the spring pins 81 and 81 is fixed so as not to rotate relative to the center of the sensor shaft 51. The plate 82 is fixed to the plurality of spring pins 81 and 81. The rotation type sensor 50 is attached to the hydraulic cylinder case 30 by inserting a plurality of holes 82a and 82a.

Therefore, by using a spigot or the like formed on the bracket between the lift arm and the sensor main body or between the hydraulic cylinder case and the sensor main body, a seat, a bracket or the like is interposed. Compared with a configuration in which the sensor shaft and the rotation shaft are aligned with each other, the dimensions in the sensor axis direction are compact. Moreover, it becomes easy to perform the operation | work which fixes the sensor main body 52 to the hydraulic cylinder case 30. FIG. That is, since it is not necessary to simultaneously adjust the position of the sensor shaft 51 (plate 82) with respect to the lift arm 60 (spring pins 81, 81) and the position of the sensor body 52 with respect to the hydraulic cylinder case 30, the rotational sensor 50 Installation can be performed easily. Furthermore, the mounting structure of the rotary sensor 50 according to the present embodiment can be realized with a small number of parts, and the manufacturing cost can be reduced. Further, since the rotary sensor 50 can be attached to the lift arm 60 and the hydraulic cylinder case 30 without using a jig, the attachment structure of a rotary encoder or the like that is easy to attach and detach and requires frequent maintenance. This is particularly effective when applied to the above.

  Although a preferred embodiment of the present invention has been described above, the following configuration may be used instead of the above embodiment.

  In the above embodiment, the plate 82 is fixed to the tip of the sensor shaft 51 by welding or caulking. However, instead of this configuration, the plate may be fixed to the sensor shaft using a nut. The attachment structure 70 shown in FIGS. 4 and 5 is a specific example in the case of such a configuration.

  The sensor shaft 71 shown in FIGS. 4 and 5 is configured as a screw shaft having a screw formed on the outer peripheral surface, and two surfaces parallel to the shaft center are formed on the outer periphery of the tip end portion of the sensor shaft 71 on the lift arm 60 side. The flat portions 71a and 71a are formed by cutting. In addition, a through hole 72b is formed in the center of the plate surface of the plate 72 so as to match the cross-sectional shape of the tip of the sensor shaft 71 so that the tip of the sensor shaft 71 can be inserted. In this way, with the tip end of the sensor shaft 71 fitted in the through hole 72 b of the plate 72, the nut 73 is screwed onto the tip of the sensor shaft 71 via the flat washer 74, and the plate 72 is attached to the sensor shaft 71. Fixed. As described above, since the flat portions 71a and 71a are formed on the sensor shaft 71, the plate 72 and the sensor shaft 71 cannot be rotated relative to each other. In addition, holes 72a and 72a for inserting spring pins 81 and 81 are opened on both sides of the through hole 72b of the plate 72. The holes 72a and 72a correspond to the holes 82a and 82a of the plate 82 in the above-described embodiment.

  As described above, the plate 72 is fixed to the sensor shaft 71 having a screw formed on the outer peripheral surface using the nut 73. With this configuration, the plate 72 can be easily attached to and detached from the sensor shaft 71. Therefore, the maintainability of the rotary sensor 50 is improved. In addition, the plate 72 can be used as a member shared with other detection type rotary sensors, and the manufacturability is improved.

  In the above embodiment, the case where the present invention is applied to the mounting structure of the rotary sensor 50 that detects the rotation angle of the lift arm 60 with respect to the hydraulic cylinder case 30 in the tractor 1 has been described. It is not limited. That is, the present invention can be widely applied to a mounting structure of a rotary sensor that detects a rotation angle between various relative rotating members.

30 Hydraulic cylinder case 50 Rotating sensor 51 Sensor shaft 52 Sensor body 60 Lift arm 80 Mounting structure (Rotating sensor mounting structure)
81 Projection 82 Plate 82a Hole C Rotation axis

Claims (2)

A lift arm is rotatably supported with respect to the hydraulic cylinder case, a rotation axis of the lift arm, and a shaft axis of a sensor shaft of the rotary sensor fixed to the hydraulic cylinder case via a mounting bracket Are mounted so as to have the same axial center, and in the mounting structure of the rotary sensor for detecting the rotation angle of the lift arm with respect to the hydraulic cylinder case,
Two pins projecting from the end of the lift arm toward the rotary sensor side are spaced apart from the rotation axis of the rotation axis of the lift arm toward the direction parallel to the rotation axis. Extension,
The two pins have two insertion holes in the rotation shaft, and the pins are fitted and fixed in the insertion hole, and are rotated from the end of the rotation shaft of the lift arm. Projects as a shaft-shaped member on the sensor side,
The sensor shaft includes a plate which is a substantially rectangular plate-like member in which two holes are formed on the plate surface facing the lift arm so as to match the two pins. And fix them so that they cannot rotate relative to each other.
On the plate surface facing the rotation axis of the plate, an insertion hole for the sensor shaft is drilled in the center of the plate,
Two holes other than the insertion hole in the central portion are opened as positions and shapes corresponding to the pins, and the tip portions of the two pins are inserted and penetrated into the two holes. Mounting structure of the rotary sensor. In the rotation sensor mounting structure according to claim 1,
The sensor shaft is configured as a screw shaft in which a screw is formed on the outer peripheral surface, and on the outer periphery of the tip end portion on the lift arm side of the sensor shaft, two planes parallel to the shaft center are cut to form a plane portion,
In the center of the plate surface of the plate, a through hole is formed in accordance with the cross-sectional shape of the tip of the sensor shaft, and the tip of the sensor shaft can be inserted,
A structure for mounting a rotary sensor, wherein a nut is screwed onto the tip of the sensor shaft and the plate is fixed to the sensor shaft in a state where the tip of the sensor shaft is fitted in the through hole of the plate .

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