AUTONOMOUSLY NAVIGING VEHICLE

Abstract

Autonomously navigating vehicle (10) equipped with a chassis (12a), a cover (12b) and a suspension mechanism (80) inserted between the chassis (12a) and the cover (12b) by a locking element (12b1) at one end, and having at least one mounting shaft (82) attached to the chassis (12a) at the other end, wherein the vehicle (10) travels on drive wheels attached to the chassis (12a), wherein the suspension mechanism (80) of the autonomously navigating vehicle (10) comprises: a tubular element (84) which is movably attached to the mounting shaft (82); a first mounting shaft retaining element (12a1) provided on the chassis (12a) to pivot the mounting shaft (82) with the pipe element (84); a lower shaft end section (821) provided on the lowest part of the mounting shaft (82); and a second mounting shaft retaining element (12a2) provided on the chassis (12a) below the first mounting shaft retaining element (12a1) to hold the mounting shaft (82); wherein an inner surface of the second mounting shaft retaining element (12a2) contains a crown-equivalent area (12a21) and a curve-equivalent area (12a22), continuous with the crown-equivalent area (12a21), the inner surface of the second fastening shaft retaining element (12a2) is formed in an arc shape when viewed in a vertical cross-section passing through the vertex equivalent region (12a21), and the second mounting shaft retaining element (12a2) holds the mounting shaft (82), wherein the lower shaft end section (821) abuts at least one of the vertex-equivalent area (12a21) and the curve-equivalent area (12a22), and wherein the autonomously navigating vehicle (10) is characterized in that the inner surface is configured such that a curvature of the arc shape in the vertical cross-section with respect to the vertex equivalent region (12a21) decreases from an outer perimeter of the inner surface in the direction of the vertex equivalent region (12a21).

Description

BACKGROUND OF THE DISCLOSURETechnical Area

[0001] The disclosure relates to an autonomously navigating vehicle, in particular to an autonomously navigating vehicle equipped with a suspension mechanism for connecting a chassis and a cover. State of the art

[0002] An autonomously navigating vehicle of this type is equipped with a suspension mechanism that slidably connects a chassis and a cover, and the present applicant has already proposed such a mechanism in WO 2017 / 109879 A1. According to the technology described in WO 2017 / 109879 A1, a suspension mechanism is inserted between a chassis and a cover in the direction of the gravity axis and is fixed at one end to a locking element of the cover and provided at another end with at least one fixing shaft to be fixed to the chassis.

[0003] The present applicant has previously proposed such an autonomously navigating vehicle in US 2019 / 0310641 A1. According to the technology described in US 2019 / 0310641 A1, the autonomously navigating vehicle includes a chassis, a shaft connected to the chassis and cables for moving back / forward, left / right, and up / down, and a cover connected to the shaft via a ball joint. When an obstacle comes into contact with the cover during vehicle operation and a certain amount of external force is applied to the cover, the shaft moves in the back / forward, left / right, and up / down directions because such obstacles are detected by increasing the distances between the magnet and the components provided in the chassis and the shaft.

[0004] The disclosure provides an autonomously navigating vehicle in which a chassis and a cover are connected by a suspension mechanism similar to that of WO 2017 / 109 879 A1 and US 2019 / 0 310 641 A1.

[0005] However, in the autonomously navigating vehicles described in US 2019 / 031 0641 A1, a damping performance at the time of impact is reduced with respect to a holding performance of the wave because an angle formed by the contact surface of the chassis and the wave is arranged almost vertically, which means that the holding performance of the wave and the damping performance at the time of impact cannot be easily adjusted individually.

[0006] EP 3 470 311 B1 discloses an autonomous vehicle in which a suspension mechanism comprises a tubular member movably mounted on a mounting shaft, an outer peripheral surface of approximately hemispherical shape, and a first mounting shaft support member provided on the chassis for pivotally supporting the mounting shaft, an outer peripheral surface of the tubular member abutting against its inner surface, a lower end portion of the shaft shape with a sliding surface provided at the lowest part of the mounting shaft, a second mounting shaft support member provided on the chassis below the first mounting shaft support member and having an apex equivalent portion of approximately conical shape and a support member for supporting the mounting shaft, the lower end portion of the sliding surface of the shaft abutting against the apex equivalent portion or the inclination equivalent portion, and a biasing member,which prestresses the tubular element and the lower end section of the shaft away from each other.

[0007] WO 2013 / 125992 A1 discloses a robotic lawnmower comprising a chassis, a body movably mounted on the chassis by means of at least one suspension, and at least one collision sensor for detecting an obstacle by sensing movement of the body relative to the chassis when the lawnmower collides with the obstacle, and for providing sensor signals indicative thereof to cause the lawnmower to react. The suspension includes a joystick element by which the body is attached to the chassis, and an elastic positioning element that holds the joystick element in a neutral position. The elastic positioning element also enables movement of the joystick element when the lawnmower collides with an obstacle and the body moves relative to the chassis, as well as a return of the joystick element to the neutral position after the collision. SUMMARY

[0008] The invention is provided by the appended claim 1. Advantageous embodiments of the invention are found in the dependent claims. According to an exemplary embodiment of the disclosure, an autonomously navigating vehicle is provided, which is equipped with a chassis, a cover, and a suspension mechanism interposed between the chassis and the cover by a locking member at one end, and which has at least one attachment shaft fixed to the chassis at the other end, the vehicle traveling on drive wheels fixed to the chassis.The suspension mechanism of the autonomously navigating vehicle includes a tubular member movably attached to the fixing shaft; a first fixing shaft support member provided on the chassis for pivotally supporting the fixing shaft with the tubular member; a lower shaft end portion provided at the lowest part of the fixing shaft; and a second fixing shaft support member provided on the chassis below the first fixing shaft support member for supporting the fixing shaft. The second fixing shaft support member includes a vertex-equivalent portion and an inner surface defined as a portion of a vertical cross section passing through the vertex-equivalent portion and formed in an arc shape. The inner surface includes a curve-equivalent portion continuous with the vertex-equivalent portion.The second fixing shaft holding member holds the fixing shaft with the lower end portion abutting against at least one of the crest equivalent region and the curve equivalent region. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Embodiments will now be described by way of example only with reference to the accompanying drawings, which are intended to be illustrative and not restrictive, and in which like elements are numbered alike in several figures. Fig. 1 is a conceptual diagram showing an overview of an autonomously navigating vehicle according to an exemplary embodiment of the disclosure. Fig. 2 is a plan view of the autonomous navigating vehicle of Fig. 1. Fig. 3 is an explanatory view of a work area used by the autonomous navigating vehicle of the Fig. 1 is used. Fig. Figure 4 is a schematic side sectional view of the suspension mechanism used to attach the cover to the chassis of the autonomously navigating vehicle of Fig. 1 is attached. Fig. 5 is a side sectional view showing operation of the suspension mechanism of Fig. 4 shows. Fig. 6 is a side sectional view similarly showing operation of the suspension mechanism of Fig. 4 shows. Fig. Fig. 7 is a side sectional view similarly showing operation of the suspension mechanism of Fig. 4 shows. Fig. Fig. 8 is a schematic view showing various configurations of the second fixing shaft support member of the suspension mechanism of Fig. 4 shows. Fig. 9 is a schematic diagram showing the relationship between the force applied to the fixing shaft and the stroke value of the cover according to the different Fig. 8 shows the configurations shown. DESCRIPTION OF THE EMBODIMENTS

[0010] In the following drawings, the scale, number, and the like may be different in each structure and the actual structure to make each configuration easy to understand. An exemplary embodiment of an autonomously navigating vehicle of the disclosure will be described below with reference to the drawings. The autonomously navigating vehicle (hereinafter referred to as "vehicle") is configured as a lawnmower. <Gesamtkonfiguration von autonom navigierendem Fahrzeug 10>

[0011] Fig. 1 is a conceptual diagram showing an overview of an autonomously navigating vehicle. According to an exemplary embodiment of the disclosure, the autonomously navigating vehicle (hereinafter referred to as "vehicle") 10 is equipped with a body 12 including a chassis (body frame) 12a and a cover 12b slidably (or detachably) attached to the chassis 12a, two relatively small-diameter front wheels 14 fixed by stays 12c to the left and right sides of the chassis 12a toward its front end in the front-rear direction, and left and right relatively large-diameter rear wheels 16 directly attached to the chassis 12a toward its rear end.

[0012] A lawnmower blade (working unit, specifically, a rotating blade) 20 is mounted near the central portion of the chassis 12a of the vehicle 10, and an electric motor (drive motor; hereinafter referred to as "working motor") 22 is installed above the blade 20. The blade 20 is connected to the working motor 22 and is rotated by the working motor 22.

[0013] A blade height adjustment mechanism 24, manually operable by a user, is connected to the blade 20. The blade height adjustment mechanism 24 is equipped with a handle and is configured to allow the user to adjust the vertical height of the blade 20 from the ground surface GR by manually rotating the handle.

[0014] Two electric motors (drive motors; hereinafter referred to as "drive motors") 26L and 26R are mounted on the chassis 12a of the vehicle 10 behind the blade 20. The drive motors 26L and 26R are connected to the left and right rear wheels 16, and while the front wheels 14 operate as free wheels, the rear wheels 16, which operate as driven wheels, are independently rotated on the left and right sides either normally (rotate to move forward) or reverse (rotate to move backward). The blade 20, the working motor 22, the drive motors 26, and other components are covered by the cover 12b.

[0015] In this embodiment, the vehicle 10 is of such weight and size that it can be transported by the user. An on-board charger 30 and a connected on-board battery 32 are housed in the rear of the utility vehicle 10, and two battery charging ports 34 are attached to the chassis 12a so that they protrude forward from a forward end position. The battery charging ports 34 are connected to the on-board charger 30. The working motor 22 and the drive motors 26 are also connected to and powered by the on-board battery 32.

[0016] The left and right magnetic sensors 36L and 36R are installed toward the front end of the body 12 of the vehicle 10, and a single magnetic sensor 36C is installed toward the rear end. The magnetic sensors 36 output signals indicating the magnetic field strength.

[0017] A contact sensor (first detection unit) 40 is attached to the body 12 to detect contact of the vehicle 10 with buildings, paving stones, people, and other obstacles, and to detect, for example, the user lifting the cover 12b from the chassis 12a upward. The contact sensor 40 is explained in more detail below.

[0018] A housing box installed near the center of the chassis 12a houses a circuit board 42 carrying an electronic control unit (control unit; hereinafter referred to as "ECU") 44, which includes a microcomputer equipped with a central processing unit (CPU), inputs / outputs (I / O), a memory (read-only memory (ROM), an electrically erasable programmable read-only memory (EEPROM), and a random access memory (RAM)), and other components.

[0019] Thereon, near the ECU 44, circuit board 42 is provided with an angular velocity sensor 46 that generates an output indicative of angular velocity (yaw rate) about a center of gravity Z-axis (axis of gravity) of the vehicle 10, an acceleration sensor 50 that generates an output indicative of acceleration acting on the vehicle 10 in orthogonal three-axis (x, y, and z) directions, a direction sensor 52 that generates an output indicative of absolute orientation in response to geomagnetism, and a GPS sensor 54 that receives radio waves from GPS satellites and generates an output indicative of the current position of the vehicle 10.

[0020] Wheel speed sensors 56 that generate outputs indicative of wheel speeds of the left and right rear wheels 16 are installed near the left and right rear wheels 16 of the vehicle 10.

[0021] A current sensor 62 that generates an output indicative of power consumption from onboard battery 32 is installed on onboard battery 32.

[0022] The utility vehicle 10 is equipped with a main switch 64 for instructing work mode and an emergency stop switch 66 for instructing emergency stop, both of which can be operated by the operator. Furthermore, the top of the cover 12b has a large cutout in which a keyboard, touch panel, or other input device 68 is installed for inputting instructions and the like by the user. A display 70 is installed near the input device 68. The input device 68 and the display 70 are connected to the ECU 44, and the display 70 displays the work mode and various other information according to the instructions from the ECU 44.

[0023] The outputs of the magnetic sensors 36, the contact sensor 40, the angular velocity sensor 46, and other sensors, as well as the outputs of the main switch 64 and other switches, are sent to the ECU 44. Based on these outputs, the ECU 44 supplies the drive motors 26 with power from the onboard battery 32 and outputs control values ​​to control navigation of the vehicle 10 by controlling the operation of the drive motors 26.

[0024] The ECU 44 detects (recognizes) a working area (work scope) AR from the outputs of the magnetic sensors 36 and accordingly supplies power to the working motor 22 to operate the working area AR.

[0025] As in Fig. As shown in Figure 3, the work area AR is delimited by a boundary cable (electric cable) 72 laid around its perimeter (boundary). A charging station 74 for charging the on-board battery 32 of the vehicle 10 is installed in the work area AR. (In Fig. 3, sizes of the vehicle 10, etc. are exaggerated.)

[0026] The vehicle 10 of the exemplary embodiment of the disclosure is characterized by a suspension mechanism connecting the chassis 12a and the cover 12b of the vehicle 10, including the configuration described above. This characteristic aspect will be described below with reference to Fig. 4 and later drawings.

[0027] Fig. 4 is a schematic side sectional view of the suspension mechanism, and Fig. 5 to Fig. 7 are side section views similar to Fig. 4, showing the operation of the suspension mechanism.

[0028] The suspension mechanism (hereinafter referred to as reference numeral 80) is arranged in the direction of the gravity axis between the chassis 12a and the cover 12b and is, as shown in Fig. 4, is attached at one end to a locking element 12b1 of the cover 12b and has at another end at least one fastening shaft 82 which is attached to the chassis 12a.

[0029] Although not shown in the drawings, a total of three suspension mechanisms 80 are installed in the vehicle 10, one above the front wheels 14 and one each above the left and right rear wheels 16.

[0030] As referred to in this specification, “gravity axis direction” means the direction of the gravity axis (vertical axis direction; Z-axis direction) in an orthogonal coordinate system when the vehicle 10, as shown in Fig. 1, on the ground surface GR is written.

[0031] As shown, the suspension mechanism 80 includes a tubular member 84, a first fixing shaft support member 12a1, a lower shaft end portion 821, a second fixing shaft support member 12a2, and a biasing member 86.

[0032] The tubular member 84 is movably mounted on the mounting shaft 82 and is shaped to have an outer peripheral surface 841 with an approximately hemispherical surface shape when viewed from the side, but the disclosure is not limited thereto. The tubular member 84 is formed with a through hole 842 in the center for movably mounting itself on the mounting shaft 82, specifically for inserting the mounting shaft 82. Furthermore, the lower part of the tubular member 84 is reduced in diameter, and a rim 843 is formed therein orthogonal to the direction of the gravity axis to protrude horizontally.

[0033] The first fixing shaft support member 12a1 formed on the chassis 12a has an inner surface 12a11 with an approximately hemispherical surface shape in side view, and is configured to pivotally support the fixing shaft 82 by abutting the outer peripheral surface 841 of the tubular member 84 on the inner surface 12a11. The inner surface 12a11 of the first fixing shaft support member 12a1 is shaped to have a shape corresponding to (i.e., a complementary shape) the outer peripheral surface 841 of the tubular member 84.

[0034] Thus, the first fixing shaft holding member 12a1 is connected to the tubular member 84 by a ball joint structure, while, as shown in Fig. 6 and Fig. 7, the fastening shaft 82 pivotally (and movably) holds between the chassis 12a and the cover 12b (more precisely between the locking element 12b1 of the cover 12b and the chassis 12a located thereunder).

[0035] The lower shaft end portion 821 is provided at the lowest part of the fixing shaft 82 in the direction of the gravity axis and is configured to have an approximately sliding surface shape in a side view. Specifically, the sliding surface shape of the lower shaft end portion 821 is formed to have an approximately hemispherical surface shape in a side view.

[0036] The upper part of the lower shaft end portion 821 is expanded in diameter, and a rim 8211 formed there orthogonal to the gravity axis direction to protrude in the horizontal direction faces the edge 843 of the tubular member 84 in the gravity axis direction. The lower shaft end portion 821 may be provided integrally with the fixing shaft 82 or provided as a separate body.

[0037] The second fixing shaft support member 12a2 is provided on the chassis 12a below the first fixing shaft support member 12a1 in the direction of the gravity axis and is configured to have a crest-equivalent portion 12a21 and an inner surface having a curve-equivalent portion 12a22 continuous with the crest-equivalent portion 12a21. The fixing shaft 82 is supported by abutting the lower shaft end portion 821, which has an approximately sliding surface shape in side view, against either the crest-equivalent portion 12a21 or the curve-equivalent portion 12a22 of the second fixing shaft support member 12a2.

[0038] The biasing element 86 even includes a compression coil elastically disposed between the tubular element 84 and the lower shaft end portion 821, specifically between the edge 843 of the tubular element 84 and the edge 8211 of the lower shaft end portion 821, to urge the tubular element 84 and the lower shaft end portion 821 away from each other, i.e., to bias them vertically in the direction of the axis of gravity. A skirt 844 is provided below the edge 843 of the tubular element 84 to align the biasing element 86 in the illustrated vertical position.

[0039] As in Fig. 4, the first fastening shaft holding element 12a1 and the second fastening shaft holding element 12a2 are connected by screws or other connecting elements 90. For simplification of illustration, Fig. 4 only one connecting element 90 is shown.

[0040] Since the connecting members 90 are sufficient to connect the first fixing shaft holding member 12a1 and the second fixing shaft holding member 12a2 as much as possible, they may instead be sealing members or the like.

[0041] The suspension mechanism 80 is additionally equipped with an upper shaft end portion 822 and a third fixing shaft support member 12b11.

[0042] The upper shaft end portion 822 is provided at the uppermost part of the fixing shaft 82 in the direction of the gravity axis and is configured to have an approximately spherical surface shape, even formed as a sphere, in side view. The upper shaft end portion 822 may be provided integrally with the fixing shaft 82 or provided as a separate body.

[0043] The third fixing shaft support member 12b11 is installed in the locking member 12b1 of the cover 12b and is actually enclosed by the locking member 12b1. It has an inner surface 12b111 with a surface shape that is approximately spherical in side view, and the fixing shaft 82 is pivotally supported by the upper shaft end portion 822 having a surface shape that is approximately spherical in side view abutting the inner surface 12b111.

[0044] More specifically, a cavity is formed in the locking element 12b1, and the upper shaft end portion 822 is fitted into the cavity. The cavity is formed such that the inner surface 12b111 has an approximately spherical surface shape in side view, which corresponds to (ie, is complementary to) the upper shaft end portion 822 having an approximately spherical surface in side view.

[0045] Thus, the third fixing shaft support member 12b11 and the upper shaft end portion 822 are connected by a ball joint structure, while, as shown in Fig. 6 and Fig. 7, the fastening shaft 82 is pivotally held between the chassis 12a and the cover 12b (more precisely, between the chassis 12a and the locking element 12b1 of the cover 12b).

[0046] Furthermore, as in Fig. 4, a sealing sleeve 92 made of rubber or other sealing material is bridged between the upper end portion 822 of the fixing shaft 82 and both the fixing position of the tubular member 84 and the chassis 12a, whereby from the third fixing shaft holding member 12b11 to the chassis 12a is covered by the sleeve 92.

[0047] To this end, below the position where the fixing shaft 82 is provided with the third fixing shaft support member 12b11, two vertically spaced flanges 823 and 824 are provided, projecting in a horizontal direction orthogonal to the gravity axis direction. The collar 92 is secured between a recess formed between the flanges 823 and 824 and an outer wall near the position where the first and second fixing shaft support members 12a1 and 12a2 of the chassis 12a are connected. Therefore, since the sealing collar 92 covers the third fixing shaft support member 12b11 across to the chassis 12a, moisture penetration therebetween is prevented.

[0048] Furthermore, a ferromagnetic magnetic body 94 including a permanent magnet or the like is installed near the lower end portion 821 of the fixing shaft 82, and a contact sensor (first detector) 40 including a magnetic sensor is installed on the underside of the chassis 12a in the direction of the gravity axis. The suspension mechanism 80 is made of synthetic resin, and the cover 12b and the chassis 12a are also made of synthetic resin.

[0049] The output of the contact sensor 40 is sent to the ECU 44, where it is compared with an appropriate threshold value to detect movement of the mounting shaft 82 in the horizontal direction orthogonal to the gravity axis direction. Displacement between the cover 12b and the chassis 12a is detected based on the comparison result, thereby detecting contact of the vehicle 10 with an obstacle. In the event that contact of the vehicle 10 with an obstacle is detected, the ECU 44 is configured to control the drive motors 26 so that the drive motors 26 rotate and change the traveling direction of the vehicle 10 when contact of the vehicle 10 with an obstacle is detected.

[0050] In addition, a magnetic body including a permanent magnet or an element to be detected, such as a metal part, is arranged on the cover 12b, and a lift sensor (second detector) 60 including a magnetic sensor is installed on the chassis 12a. According to the exemplary embodiment of the disclosure, the second detector 60 is configured to detect an upward lift of the cover 12b in the gravity axis direction based on the movement of the fixing shaft 82 in the gravity axis direction, thereby detecting that the cover 12b has been lifted, in addition to realizing the aforementioned effects.

[0051] The output of the lift sensor 60 is also sent to the ECU 44, where it is compared with an appropriate threshold value to detect movement of the fixing shaft 82 in the gravity axis direction. Whether the cover 12b has been lifted upward in the gravity axis direction, for example, by the user, is detected based on the comparison result. Furthermore, since a difference in the displacement amount, displacement direction, and displacement time of the cover 12b may be caused by a difference in the displacement amount, displacement direction, and displacement time, it is also possible that when the cover 12b is lifted, the upward lifting may be detected by the change in the output signal of the contact sensor 40 instead of the output signal of the lift sensor 60, as compared to the state where there is contact with an obstacle.Namely, the upward lifting of the cover 12b can be detected not only by the lift sensor 60, but also by the change in the output signal of the contact sensor 40. When the upward lifting is detected, the ECU 44 is configured to control the working motor 22 to stop the operation process. That is, the working motor 22 can stop operation when the upward lifting is detected.

[0052] The operation (effect) of the suspension mechanism 80 according to this embodiment will be described below with reference to Fig. 5 to Fig. 7 explained.

[0053] When no external force acts on the cover 12b relative to the chassis 12a, the suspension mechanism 80 acts to keep the fixing shaft 82 in the initial state parallel to the gravity axis direction, as shown in Fig. 5, because the tubular member 84 and the lower shaft end portion 821 are biased away from each other by the biasing member 86. When no external force acts on the cover 12b relative to the chassis 12a, the suspension mechanism 80 operates to keep the fixing shaft 82 in the initial state parallel to the direction of the gravity axis, as shown in Fig. 5, by the action of the biasing element 86, the tubular element 84 and lower shaft end portion 821 are pushed away from each other.

[0054] Namely, the suspension mechanism 80 acts to catch and immobilize the lower shaft end portion 821 at the crest equivalent portion 12a21 of the second fixing shaft holding member 12a2, thereby holding the fixing shaft 82 by means of the crest equivalent portion 12a21.

[0055] On the other hand, as in Fig. 6, the suspension mechanism 80, when a horizontal external force acts on the cover 12b relative to the chassis 12a, such as when the vehicle 10 hits an obstacle, while swinging the upper end of the fixing shaft 82 by the first fixing shaft holding member 12a1, as shown in Fig. 6 to hold the fixing shaft 82 when the lower shaft end portion 821 of the sliding mold escapes from the crest equivalent region 12a21 of the second fixing shaft holding member 12a2 and moves along the curve equivalent region 12a22.

[0056] Further, when the user applies, for example, an external force to move the cover 12b upward in the gravity axis direction relative to the chassis 12a, the suspension mechanism 80 operates as shown in Fig. 7 to move the fixing shaft 82 upward in the gravity axis direction until the tubular member 84 moves relatively downward along the fixing shaft 82 to abut against the first fixing shaft holding member 12a1 in the limit position.

[0057] This rise limit of the fixing shaft 82 is determined by the axial lengths of the fixing shaft 82 and the tubular member 84. Furthermore, the pivot angle θ of the fixing shaft 82 in the second fixing shaft holding member 12a2 ( Fig. 6) Limit of the contact angle between the tubular element 84 and the first fastening shaft holding element 12a1, so that the desired pivot angle can be realized by a suitable selection of the shape of these elements. <Konfiguration des zweiten Befestigungswellen-Halteelements 12a2>

[0058] The configuration (characteristic shapes for various functions and performances of the suspension mechanism 80) of the second fixing shaft support member 12a2 of the suspension mechanism 80 according to this embodiment will be described below with reference to Fig. 4 to Fig. 9 explained.

[0059] Fig. Fig. 8 is a schematic view showing various configurations of the second fixing shaft support member of the suspension mechanism of Fig. 4 shows. For better understanding and simplification, Fig. 8 conceptually shows four curves with four different appearances. Here in Fig. 8, the curve shown in a dashed line 12a2A, the curve shown in a solid line 12a2B, the curve shown in a double-dashed line 12a2C, and the curve shown in a single-dashed line 12a2D each show the profile of the second fixing shaft holding member 12a2 in the vertical cross section of the fixing shaft 82. Fig. 9 is a schematic diagram showing the relationship between the applied force of the fixing shaft and the stroke value of the cover according to the different Fig. 8 configurations shown. Here in Fig. 9, the curve shown in a dashed line A corresponds to the dashed line 12a2A of Fig. 8, the curve shown in a solid line B corresponds to the solid line 12a2B of Fig. 8, the curve shown in a double-dotted line C corresponds to the double-dotted line 12a2C of Fig. 8 and the curve shown in a single-dotted line D corresponds to the single-dotted line 12a2D of Fig. 8.

[0060] As in Fig. 4, Fig. 8 and Fig. As shown in FIG. 9, the second fixing shaft support member 12a2 includes a vertex equivalent portion 12a21 and an inner surface 12a22 defined as a portion of a vertical cross section passing through the vertex equivalent portion 12a21 and formed in an arc shape. The inner surface 12a22 includes a curve equivalent portion 12a22 continuous with the vertex equivalent portion 12a21, and the second fixing shaft support member 12a2 supports the fixing shaft 82 with the lower shaft end portion 821 abutting against at least one of the vertex equivalent portion 12a21 and the curve equivalent portion 12a22.The curve equivalent portion 12a22 has a shape corresponding to the lower shaft end portion 821, which has an approximately sliding surface shape in side view, more specifically, a shape on which the lower shaft end portion 821 can easily move, and the crest equivalent portion 12a21 is capable of making the lower shaft end portion 821 immobile.

[0061] Thus, the second fixing shaft support member 12a2 is configured to receive the lower shaft end portion 821 on one or the other of the crest equivalent portion 12a21 and the curve equivalent portion 12a22, that is, to support the fixing shaft 82 with the lower shaft end portion 821 immobilized by the crest equivalent portion 12a21 or slidable by the curve equivalent portion 12a22.

[0062] The shape of the lower shaft end portion 821 is not limited to an approximately hemispherical shape in side view, but may have any shape as long as it is capable of moving smoothly on the curve equivalent portion 12a22 of the second fixing shaft holding member 12a2.

[0063] As in Fig. 4, Fig. 8 and Fig. 9, the configuration of the tip portion of the second fixing shaft holding member 12a2 is an important contributor to the load or force generated when the fixing shaft 82 is tilted, since it is possible to achieve different performances of damping (for example, the restoring force of the shaft when the vehicle hits an obstacle) and holding (for example, the holding force or the initial force or the rigidity of the shaft in the initial state) depending on different configurations ( Fig. 8 and Fig. 9 show four different configurations and their corresponding performances).

[0064] In Fig. 8 and Fig. 9, the dashed line 12a22A is the profile of the tip portion of the second fixing shaft holding member 12a2, which has a Fig. 4, in which the curve-equivalent region 12a22 of the inner surface is formed as a flat surface with which the lower shaft end portion 821 is in contact. As shown in Fig. 8 and Fig. As shown in Figure 9, the curve equivalent region 12a22 has a shape with the smallest curvature (namely, having the largest radius of curvature) relative to the center of the vertex equivalent region 12a21 compared to the other three profiles (the solid line 12a22B, the double-dotted line 12a22C, and the single-dotted line 12a22D). The corresponding dashed line A of the dashed line 12a22A shows that the configuration has the largest applied force and the smallest stroke value of the cover 12b.

[0065] In Fig. 8 and Fig. 9, concerning the solid line 12a22B and the solid line B, compared with the dashed line 12a22A of Fig. 8 and the dashed line A of Fig. 9, the curve equivalent region 12a22 has a larger stroke value of the cover 12b and a smaller applied force of the fixing shaft 82, and has a smaller offset value (the offset value will be explained below). The curve equivalent region 12a22 is configured such that the curve equivalent region 12a22 includes a crest-side end portion 12a22E continuous with the crest-side equivalent region 12a21 and a circumferential end portion 12a22P, which is an outer periphery of the inner surface 12a22. In the vertical cross section passing through the vertex equivalent region 12a21, the curve equivalent region 12a22 is formed by a circular arc having a predetermined radius (the radius of curvature RC) and passes through the vertex-side end portion 12a22E and the circumferential end portion 12a22P.In other words, the circular arc (namely, the curve equivalent region 12a22) can be referred to as the arc drawn from the apex-side end portion 12a22E to the circumferential end portion 12a22P in the vertical cross section. The inner surface of the second fixing shaft support member 12a2 is defined by rotating the circular arc around a rotation axis RA passing through a center CV of the apex equivalent region 12a21 in the vertical cross section, as shown in FIG. Fig. 8. Moreover, the solid line 12a22B represents that the inner surface is configured such that the curvature of the arc shape (the circular arc of the curve equivalent region 12a22) in the vertical cross section with respect to the vertex equivalent region 12a21 decreases from the outer periphery of the inner surface toward the vertex equivalent region 12a21.

[0066] As in Fig. 8, a center CA of the circular arc is also located on an opposite side of the circular arc with the rotation axis RA as a boundary. Here, it is considered that the offset line O where the center CA of the circular arc is located is offset from the rotation axis RA to modify the configuration of the curve-equivalent region 12a22 to have a greater curvature, rather than being a very flat surface with which the lower shaft end portion 821 comes into contact, like the configuration of the curve-equivalent region 12a22 shown by the dashed line 12a22A.

[0067] In such a configuration, regarding the configuration of the curve equivalent region 12a22, the offset value (the distance between the offset line O and the rotation axis RA) and the curvature value (the radius of curvature RC) can be selectively adjusted as needed for a specific countermeasure related to the damping performance and holding performance of the vehicle. By adjusting the configuration of the curve equivalent region 12a22, an appropriate load can be set according to the displacement value of the mounting shaft in accordance with the radius of curvature RC.

[0068] In addition, two further examples of the curve equivalent region 12a22 with different functions due to different configurations of the curve equivalent region 12a22 are shown as follows. In Fig. 8 and Fig. 9, the curve equivalent area 12a22 with respect to the double-dotted line 12a22C and the double-dotted line C compared to the solid line 12a22B of Fig. 8 and the solid line B of Fig. 9, a higher stroke value of the cover 12b and a lower applied force of the fixing shaft 82, and a smaller offset value. The double-dotted line 12a22C represents that the inner surface is configured such that a curvature of the arc shape in the vertical cross section decreases from the vertex-equivalent region 12a21 toward the outer periphery of the inner surface.

[0069] In Fig. 8 and Fig. 9, the curve equivalent area 12a22 with respect to the single-dotted line 12a22D and the single-dotted line D compared to the double-dotted line 12a22C of Fig. 8 and the double-dotted line C of Fig. 9 has a higher stroke value of the cover 12b and a lower applied force of the fixing shaft 82 and has a smaller offset value.

[0070] In such a configuration, in order to modify the configuration of the curve equivalent region 12a22 as an actual requirement, the value of the offset (the distance between offset line O and rotation axis RA) and the value of the curvature (the radius of curvature RC) can be selectively adjusted to achieve a special countermeasure with respect to the damping performance and the holding performance of the vehicle.

[0071] According to the exemplary embodiment of the disclosure, the autonomously navigating vehicle 10 includes a plurality of suspension mechanisms 80, for example, it includes three suspension mechanisms 80, one of which is attached to the front wheel and two of which are attached to the rear wheels, as mentioned above. The three suspension mechanisms 80 attached to different locations of the vehicle 10 may have different configurations of the second attachment shaft support member 12a2, that is, the inner surface is configured such that a curvature of the arc shape in the vertical cross section is different depending on the plurality of suspension mechanisms 80. For example, the suspension mechanism 80 having higher damping performance than holding performance, for example, the curve equivalent region 12a22 indicated by the double-dashed line 12a22C in Fig. 8, are mounted on the front part (e.g., the front wheels 14) of the vehicle 10, so that the load of the fixing shaft 82 increases according to the displacement of the fixing shaft 82 to ensure cushioning of the impact in the front-back direction; whereas the suspension mechanism 80, which has a higher restraining performance than a cushioning performance, e.g., the curve equivalent area 12a22 indicated by the solid line 12a22B in Fig.8, can be mounted on the rear part (e.g., on each rear wheel 16) of the vehicle 10, so that the load can be increased at a position where the displacement of the mounting shaft 82 is comparatively smaller to avoid erroneous detection of the obstacle detection function. In such a configuration, suspension mechanisms 80 with different functions can be selected to be mounted on different parts of the vehicle 10 according to actual requirements.

[0072] On the other hand, the suspension mechanism having the configuration of the curve equivalent region 12a22 shown with the single-dotted line 12a22D, which has the largest stroke value of the cover 12b (the largest damping performance) among the four examples, may be suitable for use when the vehicle 10 runs on a comparatively flat road (the possibility of obstacle collision may be very small), since the initial force may be comparatively lower and the load of displacement may be comparatively larger.

[0073] As illustrated in the embodiment of the disclosure, the curve equivalent region includes a crown-side end portion continuous with the crown equivalent region and a circumferential end portion that is an outer periphery of the inner surface. In the vertical cross section passing through the crown equivalent region, the curve equivalent region is formed by a circular arc with a predetermined radius and passes through the crown-side end portion and the circumferential side end portion. The inner surface is defined by rotating the circular arc around a rotation axis passing through a center of the crown equivalent region in the vertical cross section. As such, an appropriate load can be set according to the displacement amount of the fixing shaft according to the radius of the circular arc.

[0074] As shown in the embodiment of the disclosure, the curve-equivalent region is configured such that the center of the circular arc is located on the opposite side of the circular arc with the rotation axis as the boundary. Thus, erroneous detection can be prevented by setting a higher initial load on the fixing shaft in the initial state.

[0075] As shown in the embodiment of the disclosure, the inner surface is configured such that a curvature of the arc shape in the vertical cross section with respect to the apex-equivalent region decreases from an outer periphery of the inner surface toward the apex-equivalent region. Thus, in a case where an obstacle collides with the vehicle, the load on the mounting shaft can increase in accordance with the displacement of the mounting shaft, thereby improving the damping performance at the time of collision and reducing the impact transmitted to the chassis.

[0076] As shown in the embodiment of the disclosure, the inner surface is configured so that the curvature of the arc shape in the vertical cross section decreases from the apex-equivalent region toward the outer periphery of the inner surface. Thus, the load can be increased at a position where the displacement of the mounting shaft is comparatively smaller, and erroneous detection of the obstacle detection function can be prevented even in a case where the vehicle is traveling on uneven roads.

[0077] As shown in the embodiment of the disclosure, the inner surface is configured such that the curvature of the arc shape in the vertical cross-section differs depending on whether the vertical cross-section extends in the front-backward direction of the traveling direction and whether the vertical cross-section extends in the left-right direction of the traveling direction. Thus, an appropriate load can be set even when the possibility of collision with an obstacle and the impact of the obstacle collision differ depending on the impact applied from the front-backward direction and the left-right direction.

[0078] As illustrated in the embodiment of the disclosure, the suspension mechanism of the autonomously navigating vehicle further includes a biasing member elastically disposed between the tubular member and the lower shaft end portion to bias the tubular member and the lower shaft end portion away from each other. Thus, the chassis and the cover can be reliably connected by the suspension mechanism, and the holding performance of the fixing shaft can be improved, whereby the holding configuration of the fixing shaft can effectively prevent vibration of the cover and reduce vehicle running noise.

[0079] As illustrated in the embodiment of the disclosure, the autonomously navigating vehicle includes a plurality of suspension mechanisms, and the inner surface is configured such that the curvature of the arc shape in the vertical cross section varies depending on the plurality of suspension mechanisms. Thus, an appropriate load can be set depending on the configuration positions of the suspension mechanisms of the vehicle. For example, the suspension mechanism having higher damping performance than holding performance may be mounted on the front part (e.g., on the front wheel) of the vehicle so that the load on the fixing shaft increases according to the displacement of the fixing shaft to ensure cushioning of the impact in the front-backward direction; whereas the suspension mechanism having higher holding performance than damping performance may be mounted on the rear part (e.g.,The suspension mechanism can be mounted on a position where the displacement of the mounting shaft is comparatively smaller (e.g., on the rear wheels) of the vehicle, allowing the load to be increased at a position where the displacement of the mounting shaft is comparatively smaller, thus avoiding erroneous detection of the obstacle detection function. In such a configuration, suspension mechanisms with different functions can be selected to be mounted on different parts of the vehicle according to actual requirements.

[0080] As shown in the embodiment of the disclosure, the predetermined radius of the circular arc of the curve-equivalent region is set so that a load applied to the mounting shaft is constant with respect to a displacement amount of the lower shaft end portion. Thus, an impact or contact with an obstacle can be accurately detected.

[0081] In view of the foregoing, the autonomously navigating vehicle, as illustrated in the embodiment of the disclosure, is equipped with a suspension mechanism disposed between the chassis and the cover. The suspension mechanism is provided with a first fixing shaft support member and a second fixing shaft support member that detects when an obstacle comes into contact with (or impacts) the vehicle. The disclosure describes that the portion of the second fixing shaft support member provided with a contact sensor is designed to have different configurations with their own special functions, such as the arc shapes in the vertical cross section of the fixing shaft, which are characterized by different curvatures and have particular advantages in terms of damping performance and holding performance.According to the disclosure, the angle between the contact surface of the chassis and the shaft, which contributes greatly to the load when the shaft is tilted, can be maintained at an angle tilted by a certain amount from the vertical position even when the shaft is tilted, making it possible to maintain a sufficiently high load after the cover is moved. By configuring the size of the radius of the arc shape and the offset amount between the center of the vertex equivalent region and the rotation axis of the arc shape, it is possible to arbitrarily adjust the holding force in the adjusted state and the load after the cover is moved, thereby improving both the holding performance and the damping performance of the autonomous navigating vehicle according to the assembly of the suspension mechanisms as required.

[0082] The embodiment and example of the disclosure are described above; however, the disclosure is not limited to the above-described embodiment and can be modified and changed in various ways within the scope of the gist of the disclosure. The embodiment and its modifications are included within the scope and gist of the disclosure and are included in the disclosure described in the claims and their equivalent scopes. <Gewerbliche Anwendbarkeit>

[0083] The autonomously navigating vehicle according to this disclosure can advantageously be used as an unmanned, autonomously navigating vehicle. DESCRIPTION OF REFERENCE SYMBOLS

[0084] 10 autonomously navigating vehicle (vehicle), 12 body, 12a chassis, 12a1 first fixing shaft support member, 12a11 inner surface, 12a2 second fixing shaft support member, 12a21 crown equivalent region, 12a22 curve equivalent region, 12a22E crown side end portion, 12a22P circumferential side end portion, 12b cover, 12b1 locking member, 12b11 third fixing shaft support member, 12b111 inner surface, 14 front wheels, 16 rear wheels, 20 blade, 22 electric motor (working motor), 24 blade height adjustment unit, 26 electric motor (driving motor), 30 on-board charger, 32 on-board battery, 34 battery charging port, 36L, 36R, 36C Magnetic sensors, 40 Contact sensor, 44 Electronic control unit (ECU), 46 Angular velocity sensor, 50 Acceleration sensor, 52 Direction sensor, 54 GPS sensor, 56 Wheel speed sensor, 60 Stroke sensor, 62 Current sensor, 68 Input device, 70 Display, 72 Boundary wire, 74 Charging station, 80 Suspension mechanism, 82 Mounting shaft,821 lower shaft end section, 8211 rim, 822 upper shaft end section, 823, 824 flanges, 84 tubular element, 841 outer peripheral surface, 843 rim, 90 connecting element, 92 sleeve, 94 magnetic body, AR working area,

Claims

[1] An autonomously navigating vehicle (10) equipped with a chassis (12a), a cover (12b), and a suspension mechanism (80) interposed between the chassis (12a) and the cover (12b) by a locking member (12b1) at one end, and having at least one fixing shaft (82) fixed to the chassis (12a) at the other end, the vehicle (10) traveling on drive wheels fixed to the chassis (12a), the suspension mechanism (80) of the autonomously navigating vehicle (10) comprising: a tubular member (84) movably mounted to the mounting shaft (82); a first fixing shaft support member (12a1) provided on the chassis (12a) for pivotally supporting the fixing shaft (82) with the tubular member (84); a lower shaft end portion (821) provided at the lowermost part of the fixing shaft (82); and a second fixing shaft support member (12a2) provided on the chassis (12a) below the first fixing shaft support member (12a1) for supporting the fixing shaft (82); wherein an inner surface of the second fixing shaft holding member (12a2) includes a vertex equivalent region (12a21) and a curve equivalent region (12a22) continuous with the vertex equivalent region (12a21), the inner surface of the second fixing shaft holding member (12a2) is formed in an arc shape when viewed in a vertical cross section passing through the vertex equivalent region (12a21), and the second fastening shaft holding element (12a2) holds the fastening shaft (82), wherein the lower shaft end portion (821) abuts against at least one of the apex-equivalent region (12a21) and the curve-equivalent region (12a22), and wherein the autonomously navigating vehicle (10) characterized byis that the inner surface is configured such that a curvature of the arc shape in the vertical cross section with respect to the vertex equivalent region (12a21) decreases from an outer periphery of the inner surface toward the vertex equivalent region (12a21). [2] Autonomously navigating vehicle (10) according to claim 1, wherein the curve-equivalent region (12a22) includes a vertex-side end portion (12a22E) continuous with the vertex-equivalent region (12a21) and a circumferential side end portion (12a22P) which is an outer periphery of the inner surface, when viewed in the vertical cross section passing through the vertex equivalent region (12a21), the curve equivalent region (12a22) is formed by a circular arc having a predetermined radius and passing through the vertex-side end portion (12a22E) and the circumferential side end portion (12a22P), and the inner surface is defined by rotating the circular arc about a rotation axis (RA) passing through a center (CV) of the vertex equivalent region (12a21) when viewed in the vertical cross-section. [3] Autonomously navigating vehicle (10) according to claim 2, wherein, viewed in the vertical cross section, the circle center (CV) of the circular arc is located on a side of the fixing shaft (82) which, with the rotation axis (RA) as a boundary, is opposite to the curve equivalent region (12a22). [4] The autonomously navigating vehicle (10) of claim 1, wherein the suspension mechanism (80) of the autonomously navigating vehicle (10) further comprises: a biasing member (86) elastically interposed between the tubular member (84) and the lower shaft end portion (821) to bias the tubular member (84) and the lower shaft end portion (821) away from each other. [5] The autonomously navigating vehicle (10) according to claim 1, wherein the autonomously navigating vehicle (10) comprises a plurality of suspension mechanisms (80), and the inner surface is configured such that a curvature of the arc shape, viewed in the vertical cross section, is different depending on the plurality of suspension mechanisms (80). [6] The autonomously navigating vehicle (10) according to claim 2, wherein the predetermined radius of the circular arc of the curve equivalent region (12a22) is set so that a load applied to the fixing shaft (82) is constant with respect to a displacement amount of the lower shaft end portion (821).

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