Patent Description:
Conventionally, there has been proposed a technology that installs a positioning unit that detects the position of a vehicle body in a roll-over protection structure (ROPS) frame of a tractor (see, for example, Patent Document <NUM>). The ROPS frame is a guard provided around a driver seat area so as to protect the driver in the event of a fall in a tractor without a ceiling and pillars to support the ceiling, and is erected in an inverted U shape at the back of the driver seat area on the vehicle body, for example.

This document discloses a work vehicle comprising: a vehicle body to which a work instrument is connected at a back portion of a driver seat area; and a roll-over protection structure (ROPS) frame erected at a back portion of a driver seat area in the vehicle body, wherein the work vehicle further comprises: a positioning unit that detects a position of the vehicle body based on a signal sent from a positioning satellite, and a support unit that is fixed to an upper portion of the ROPS frame and supports the positioning unit from below, and the positioning unit has a harness connection portion that is connected to a harness for sending information to outside, the support unit is located protruding backwardly from the harness connection portion of the positioning unit.

The information acquired by the positioning unit (e.g., position information of tractor) is sent to a controller via a harness. For example, if a connection portion with a harness (hereinafter referred to as "harness connection portion") is provided at the back portion of the positioning unit; when a work instrument connected to the back of the tractor body is raised while the positioning unit is fixed to the upper portion of the ROPS frame, there is a risk of the harness connection portion of the positioning unit coming into contact with the work instrument and being damaged.

The present invention has been made to solve the above problem; it is therefore an object of the present invention to provide a work vehicle that can reduce the risk of the harness connection portion of the positioning unit coming into contact with the work instrument and being damaged.

A work vehicle according to one aspect of the present invention includes: a vehicle body to which a work instrument is connected at a back; and a ROPS frame erected at a back portion of a driver seat area in the vehicle body wherein the work vehicle further includes: a positioning unit that detects a position of the vehicle body based on a signal sent from a positioning satellite, and a support unit that is fixed to an upper portion of the ROPS frame and supports the positioning unit from below, wherein the positioning unit has a harness connection portion that is connected to a harness for sending information to outside, and wherein the harness connection portion is located at a back portion of the positioning unit, and wherein the support unit is located protruding backwardly from the harness connection portion of the positioning unit.

The above configuration can reduce the risk the harness connection portion of the positioning unit coming into contact with the work instrument and being damaged.

The following is a description of an embodiment of the present invention based on the drawings. In the present embodiment, a tractor will be described as an example of a work vehicle. In addition to the tractor, examples of the work vehicle include riding work vehicles such as a rice transplanter, a combine harvester, a civil engineering and construction work device, and a snowplow.

In this description, directions are defined as follows. First, the direction in which the tractor as the work vehicle proceeds during work is defined as "front" and the opposite direction is defined as "back". The right side toward the proceeding direction of the tractor is defined as right, and the left side is defined as left. The direction perpendicular to the front-back and left-right directions of the tractor is defined as a vertical direction. In this case, the direction of gravity is downward and the opposite side is upward. In the drawings, the front direction is indicated by F, the back direction by B, the left direction by L, the right direction by R, the upward direction by U, and the downward direction by D.

<FIG> is a schematic side view of a tractor <NUM> which is an example of a work vehicle of the present embodiment. <FIG> is a block diagram of a vehicle travel system including the tractor <NUM>.

As shown in <FIG>, the vehicle travel system is composed of the tractor <NUM>, a wireless communication terminal <NUM>, and a reference station <NUM>. The tractor <NUM> can travel according to the operation of the driver or can travel autonomously based on an instruction or the like from the wireless communication terminal <NUM>. The wireless communication terminal <NUM> is a terminal for giving various instructions, etc. to the tractor <NUM>. The reference station <NUM> is provided so as to obtain position information of the tractor <NUM>.

As shown in <FIG>, the tractor <NUM> includes a vehicle body <NUM>. At the back of the vehicle body <NUM>, a work instrument <NUM> can be mounted. That is, the tractor <NUM> is equipped with the vehicle body <NUM> to which work instrument <NUM> is connected at the back. The work instrument <NUM> can be, for example, but is not limited to, cultivators, plows, and fertilizer application equipment.

The front portion of the vehicle body <NUM> is supported by a pair of left-right front wheels <NUM>. The back portion of the vehicle body <NUM> is supported by a pair of left-right back wheels <NUM>. In the front portion of the vehicle body <NUM>, a hood <NUM> is located. An engine <NUM> as a drive source is located below the hood <NUM>. The engine <NUM> is composed of a diesel engine, for example, but is not limited to this and may be composed of a gasoline engine, for example. In addition to or instead of the engine <NUM>, an electric motor may be used as the drive source.

In the upper center portion in the front-back direction in the vehicle body <NUM>, a driver seat area <NUM> is provided for a man operator (driver). The driver seat area <NUM> is equipped with a steering wheel <NUM> for the driver to make a steering operation, and a driver seat <NUM> for the driver. Although not shown in the drawing, the driver seat area <NUM> is provided with control levers, pedals, etc. operated by the driver.

A three-point link mechanism is provided on the back side of the vehicle body <NUM>. The three-point link mechanism is composed of a pair of left-right lower links <NUM> and an upper link <NUM>. The work instrument <NUM> is configured to be mountable to the three-point link mechanism. A raising-lowering device (not shown) with a hydraulic system such as a lifting cylinder is provided at the back side of the vehicle body <NUM>. The raising-lowering device raises and lowers the three-point link mechanism, thereby making it possible to raise and lower the work instrument <NUM>.

In the vehicle body <NUM>, a ROPS frame <NUM> is provided at the back portion of the driver seat area <NUM> (driver seat <NUM>). The ROPS frame <NUM> is a safety frame (guard) provided for the purpose of protecting the man operator in the event that the tractor <NUM> tips over, as described above. The ROPS frame <NUM> is composed of a hollow frame, and is erected in an inverted U-shape at the back portion of the driver seat area <NUM>. That is, the tractor <NUM> is equipped with the ROPS frame <NUM> that is erected at the back portion of the driver seat area <NUM> in the vehicle body <NUM>. The height of the ROPS frame <NUM> can be set as needed within the range specified by the regulations.

The ROPS frame <NUM> is so configured that two longitudinal frames 60b extending in the vertical direction are each connected to one end of the transverse frame 60a (see <FIG>, etc.) extending in the left-right direction. The coupling portion between the transverse frame 60a and the longitudinal frame 60b is rounded (curvature). This results in the inverted U-shaped ROPS frame <NUM> described above.

As shown in <FIG>, tractor <NUM> is provided with a governor unit <NUM> that can adjust the rotational speed of engine <NUM> and a transmission unit <NUM> that changes the speed and transmits the rotational drive power from the engine <NUM> to the drive wheels. The governor unit <NUM> and transmission unit <NUM> are controlled by a control unit <NUM>.

The tractor <NUM> is equipped with a steering unit <NUM>. The steering unit <NUM> is provided, for example, at the midpoint of the rotational axis of the steering wheel <NUM> and is configured to adjust the rotational angle (steering angle) of the steering wheel <NUM>. By the control unit <NUM> controlling the steering unit <NUM>, the tractor <NUM> can not only drive straight ahead, but also turn the steering wheel <NUM> at a desired angle, and can make a turn at a desired turning radius.

The tractor <NUM> is further equipped with an antenna unit <NUM>. The antenna unit <NUM> is a positioning unit that detects the position of vehicle body <NUM> based on a signal sent from a positioning satellite (navigation satellite) <NUM> shown in <FIG>.

The antenna unit <NUM> and the control unit <NUM> are electrically connected by a harness WH. This can send various information or instructions between the antenna unit <NUM> and the control unit <NUM> via the harness WH. For example, the vehicle body <NUM>'s position information detected by the antenna unit <NUM> is input to the control unit <NUM> via the harness WH.

Details of the antenna unit <NUM> are described below. The antenna unit <NUM> has an inertial measurement unit (IMU) <NUM>, a GNSS (Global Navigation Satellite System) antenna <NUM>, a wireless communication unit <NUM>, a wireless communication antenna <NUM>, and a base station antenna <NUM>.

The inertial measurement unit <NUM> is equipped with a <NUM>-axis gyro sensor and a <NUM>-way accelerometer, which detects angular velocity and acceleration in three dimensions. The detected value of the inertial measurement unit <NUM> is input to the control unit <NUM>. The control unit <NUM> can obtain the attitude information of the tractor <NUM> based on the above detected value. The above attitude information includes, for example, the azimuth angle of a machine body (yaw angle), the left-right tilt angle of the machine body (roll angle), and the front-back tilt angle in the direction where the machine body is proceeding (pitch angle).

The GNSS antenna <NUM> receives radio signals sent from a positioning satellite <NUM> that forms a satellite positioning system (GNSS). In the satellite positioning system, in addition to GPS (Global Positioning System; U. ), Quasi-Zenith Satellite System (Japan), GLONASS satellite (Russia) or the like can be used as positioning satellites.

The wireless communication unit <NUM> sends and receives various signals via a wireless communication network formed in combination with the wireless communication terminal <NUM> and other devices. In the present embodiment, the wireless communication unit <NUM> is a Wifi (registered trademark) unit with a frequency band of <NUM>. Signals sent from the wireless communication terminal <NUM> are received by the wireless communication antenna <NUM> and, and are input to the control unit <NUM> via the wireless communication unit <NUM>. In addition, signals from the control unit <NUM> are sent via the wireless communication unit <NUM> and the wireless communication antenna <NUM> to a wireless communication unit <NUM>, etc. of the wireless communication terminal <NUM>.

Here, for example, RTK (Real Time Kinematic) positioning is used in the present embodiment, as a positioning method using the satellite positioning system. In the RTK positioning, the carrier phase (satellite positioning information) from the positioning satellites <NUM> is measured by both of a reference station positioning antenna <NUM> of the reference station <NUM> installed at the reference point, and the GNSS antenna <NUM> of the tractor <NUM> that is on the mobile station side of the target for which the position information is sought. At the reference station <NUM>, correction information is generated each time the satellite positioning information is measured from the positioning satellite <NUM>, or each time a set period elapses. The above correction information is sent from a reference station radio communication unit <NUM> to the base station antenna <NUM> of the tractor <NUM>. Using the correction information sent from the reference station <NUM>, the control unit <NUM> of the tractor <NUM> corrects the satellite positioning information measured by the GNSS antenna <NUM>, thereby to seek the current position information of the tractor <NUM>. The control unit <NUM> seeks, for example, latitude information and longitude information as the current position information of the tractor <NUM>.

The positioning method used is not limited to the RTK positioning described above, and other positioning methods such as DGPS (differential GPS positioning) may also be used. Further, the reference station <NUM> can send and receive various information not only to and from the tractor <NUM>, but also to and from the wireless communication terminal <NUM>.

The wireless communication terminal <NUM> is composed of, for example, a tablet type personal computer having a touch screen, and the like. The wireless communication terminal <NUM> is provided with a wireless communication unit <NUM> and a route generating unit <NUM> that generates a target travel route. Based on various information input at the touch screen, the route generating unit <NUM> can generate the target travel route for autonomous driving of the tractor <NUM>. The route generating unit <NUM> is composed of a CPU (Central Processing Unit), for example, owned by the personal computer.

The wireless communication terminal <NUM> sends various information to the tractor <NUM> for autonomous driving of the tractor <NUM>, such as the target travel route. The control unit <NUM> of the tractor <NUM> controls the transmission unit <NUM>, the steering unit <NUM>, etc., based on the tractor <NUM>'s current position information required from receiving signals, etc., of the GNSS antenna <NUM> and on the vehicle body <NUM>'s attitude information (displacement information, orientation information) required from the detected value at the inertial measurement unit <NUM>. This allows the tractor <NUM> to travel autonomously along the target travel route generated by the route generating unit <NUM>.

As shown in <FIG>, the tractor <NUM> is further equipped with a support unit <NUM>. The support unit <NUM> is fixed to the upper portion of the ROPS frame <NUM>, and supports the antenna unit <NUM> from below. The antenna unit <NUM> is thus fixed to the upper portion of the ROPS frame <NUM> via the support unit <NUM>.

In the present embodiment, from the viewpoint of reducing the effect of the tractor <NUM>'s vibration on the position detection accuracy of the antenna unit <NUM>, the antenna unit <NUM> is supported by the support unit <NUM> so that the gravitational center of the antenna unit <NUM> is located in the ROPS frame <NUM>'s center in the front-back direction. Details of the configuration of the support unit <NUM> are described below.

<FIG> is a perspective view of the antenna unit <NUM> and the support unit <NUM> seen from above, with the antenna unit <NUM> fixed to the ROPS frame <NUM> via the support unit <NUM>. <FIG> is a plan view of the antenna unit <NUM> and support unit <NUM>. <FIG> is a perspective view of the support unit <NUM>, with the antenna unit <NUM> in <FIG> omitted. In the present embodiment, the support unit <NUM> functions not only as a support member to support the antenna unit <NUM>, but also functions as a protective member to protect a harness connection portion <NUM> (see <FIG>) of the antenna unit <NUM>. Herein, the harness connection portion <NUM> is to be described.

As shown in <FIG>, the harness connection portion <NUM> of the antenna unit <NUM> is a connector (coupler) connected to the harness WH described above. The terminal on one end side of the harness WH is connected to the harness connection portion <NUM>, and the terminal on the other end side is connected to the control unit <NUM> (see <FIG>), thereby to make it possible to electrically connect the antenna unit <NUM> and the control unit <NUM>. Then, various information acquired at the antenna unit <NUM> (position information, correction information, posture information, etc.) can be sent via the harness WH to the outside (herein, the control unit <NUM>). Thus, the antenna unit <NUM> has a harness connection portion <NUM> that is connected to the harness WH for sending information to the outside.

The harness connection portion <NUM>'s position in the antenna unit <NUM> is not limited, but in the present embodiment, the harness connection portion <NUM> is positioned at the back portion of the antenna unit <NUM>. This is due to the following reason.

For example, in a configuration where the harness connection portion <NUM> is provided on the bottom face of the antenna unit <NUM> and the harness WH connected to the harness connection portion <NUM> is caused to pass through the inside of the ROPS frame <NUM>, it is necessary to provide a hole, which is used for the harness WH to pass through, on the upper face of the ROPS frame <NUM> (the face in contact with the bottom face of the antenna unit <NUM>). There is a concern that providing the hole in the ROPS frame <NUM> may reduce the strength of the ROPS frame <NUM>.

In the configuration where the harness connection portion <NUM> is located at the back portion of the antenna unit <NUM>, as in the present embodiment, the harness WH connected to the harness connection portion <NUM> can be pulled around outside the ROPS frame <NUM>. Therefore, there is no need to provide the hole in the ROPS frame <NUM> for the harness WH to pass through. This can prevent the strength of the ROPS frame <NUM> from being reduced due to drilling of the hole in the ROPS frame <NUM>. In addition, since the harness WH can be pulled around behind the ROPS frame <NUM>, the harness WH does not become an obstacle for the driver operating in the driver seat area <NUM> in front of the ROPS frame <NUM>.

As shown in <FIG>, the support unit <NUM> is located protruding from the harness connection portion <NUM> of the antenna unit <NUM>. Details of the support unit <NUM> will be described below, but in the present embodiment, a protective pipe <NUM>, which is a protective member of the support unit <NUM>, has a back end located behind the harness connection portion <NUM> (see <FIG>). From this, it can be said that the support unit <NUM> having the protective pipe <NUM> is located protruding backward from the harness connection portion <NUM>.

With such a positional relation between the antenna unit <NUM> and the support unit <NUM>; even when the work instrument <NUM> (see <FIG>) connected to the back of the vehicle body <NUM> is raised, the support unit <NUM> can prevent the harness connection portion <NUM> of the antenna unit <NUM>, which is fixed to the ROPS frame <NUM> via the support unit <NUM> (in particular, the protective pipe <NUM> described below), from coming into contact with the work instrument <NUM>. This reduces the risk of the harness connection portion <NUM> coming into contact with the work instrument <NUM> and being damaged.

For example, it can be so configured that the upper portion of the ROPS frame <NUM> can turn backward (bendable) so as to prevent the upper portion of the ROPS frame <NUM> from contacting the upper portion of the barn doorway when the tractor <NUM> is to be stored in the barn. Even when the antenna unit <NUM> is fixed via the support unit <NUM> to the ROPS frame <NUM> with the above configuration, the support unit <NUM> can prevent the harness connection portion <NUM> of the antenna unit <NUM> from coming into contact with the work instrument <NUM> when the upper portion of the ROPS frame <NUM> turns backward. Therefore, even when it is so configured that the upper portion of the ROPS frame <NUM> can turn backward, supporting the antenna unit <NUM> using the support unit <NUM> of the present embodiment can reduce the risk of the harness connection portion <NUM> coming into contact with the work instrument <NUM> and being damaged.

In particular, the harness connection portion <NUM> is located protruding backward from a back face 50B of the antenna unit <NUM>. The back face 50B refers to ae backward-facing face in the antenna unit <NUM>.

When the harness connection portion <NUM> is located protruding backward from the back face 50B of the antenna unit <NUM>, the harness connection portion <NUM> may be damaged by contact with the outside. Therefore, so as to prevent the harness connection portion <NUM> from contacting the work instrument <NUM>, the configuration of the present embodiment, in which the support unit <NUM> is located more backwardly than the harness connection portion <NUM>, is very effective.

As shown in <FIG>, with the antenna unit <NUM> fixed to the ROPS frame <NUM> via the support unit <NUM>, the harness connection portion <NUM> of the antenna unit <NUM> is located behind the ROPS frame <NUM>. That is, the support unit <NUM> supports the antenna unit <NUM> so that the harness connection portion <NUM> is located behind the ROPS frame <NUM>.

This configuration ensures that the harness WH, which is connected to the harness connection portion <NUM>, can be pulled around behind the ROPS frame <NUM>. Thus, it is possible to reliably distribute the harness WH that becomes the obstacle for the driver operating in the driver seat area <NUM> in front of the ROPS frame <NUM>.

Details of the configuration of the support unit <NUM> described above will now be described based on <FIG> and <FIG>, with reference to <FIG>. <FIG> is a perspective view of the support unit <NUM> seen from below. <FIG> is a side view of the support unit <NUM>. The support unit <NUM> has a support plate <NUM>, which is a support member, a protective pipe <NUM>, a fixing plate <NUM>, and a fixing stay <NUM>.

The support plate <NUM> is a base to which the antenna unit <NUM> is fixed and is located below the antenna unit <NUM>. In the present embodiment, a through hole 71P (see <FIG>), which passes through in the vertical direction, is provided at an arbitrary location on the support plate <NUM>. In the present embodiment, there are three through holes 71P in the support plate <NUM>, but the number of through holes 71P is not particularly limited. Inserting a first bolt <NUM> (see <FIG> and <FIG>) into the through hole 71P from the opposite side of the antenna unit <NUM> and screwing the first bolt <NUM> with a nut (not shown) provided on the antenna unit <NUM> side fixes the antenna unit <NUM> to the support plate <NUM>. That is, the antenna unit <NUM> is supported from below by the support plate <NUM>. Therefore, the support unit <NUM> can be said to have the support plate <NUM> that supports the antenna unit <NUM> from below. The above screwing means that the bolt is turned to join with the nut.

As shown in <FIG> and <FIG>, the support plate <NUM> is composed of a flat plate with edges. The above edges include a front edge 71F protruding forward, a left edge <NUM> located on the left side and approximately along the front-back direction, a back portion edge 71B located at the back portion and approximately along the left-right direction, and a right edge 71R located on the right side and approximately along the front-back direction. As a result, the support plate <NUM> is pentagonal home plate shaped in plan view. The support plate <NUM> may be any other polygonal shape, such as a square, or any shape other than a polygon (circle, oval, etc.) in plan view. The support plate <NUM> is made of metal, such as stainless steel, for example, but may also be made of resin as long as being able to secure strength.

The protective pipe <NUM> is a hollow metal pipe and is mounted to a portion of the edge of the support plate <NUM>. More particularly, the protective pipe <NUM> is mounted to the back portion edge 71B, the left edge <NUM> and right edge 71R of the support plate <NUM> by welding or any other operation. Like the support plate <NUM>, the protective pipe <NUM> may also be made of resin. In this case, any method can be selected for fixing the support plate <NUM> and the protective pipe <NUM>, such as a method using fixing jigs (bolts and nuts). Details of the protective pipe <NUM> are described below.

The fixing plate <NUM> is located along a front face <NUM> of the ROPS frame <NUM> and is fixed to the protective pipe <NUM> by welding or any other operation. The front face <NUM> of the ROPS frame <NUM> refers to a face positioned on the front side (the face turning forward) in the transverse frame 60a and longitudinal frame 60b of the ROPS frame <NUM>.

The fixing plate <NUM>, in the left-right direction, has two through holes (not shown) that pass through in the front-back direction. In the fixing plate <NUM>, the above through holes are so formed as to correspond to the positions of two front positioning nuts <NUM> fixed to the ROPS frame <NUM> (see <FIG>). The front positioning nut <NUM> is composed of a nut having a long through-hole in the front-back direction (so-called high nut), and is welded or otherwise connected to a lower face 60a1 of the transverse frame 60a of the ROPS frame <NUM>. On the lower face 60a1 of the transverse frame 60a, the front positioning nut <NUM> is located at the front side of the center in the front-back direction.

Therefore, inserting the second bolt <NUM> (see <FIG> and <FIG>) from the front into the above through hole of the fixing plate <NUM> and screwing the second bolt <NUM> with the front positioning nut <NUM> of the ROPS frame <NUM> can fix the fixing plate <NUM> to the ROPS frame <NUM>.

The fixing stay <NUM> is a metal plate used to fix the support plate <NUM> to the ROPS frame <NUM>. The fixing stay <NUM> is formed by bending both end portions of a single elongated metal plate in a direction that brings them closer together at an angle of approximately <NUM>°. In <FIG>, one end portion of the fixing stay <NUM> has a first through-hole 74a that passes through in the vertical direction, and the other end portion has a second through-hole 74b that passes through in the front-back direction.

A U-shaped metal fitting 71C, which is U-shaped in lateral view, is mounted to the lower face of the support plate <NUM>. A through hole 71C1, which passes through in the vertical direction, is formed in the bottom face of the U-shaped metal fitting 71C.

As shown in <FIG>, a back positioning nut <NUM> is welded or otherwise coupled to the lower face 60a1 of the transverse frame 60a of the ROPS frame <NUM>. The back positioning nut <NUM> is composed of a nut (high nut) having a long through-hole in the front-back direction. On the lower face 60a1 of the transverse frame 60a, the back positioning nut <NUM> is located backward of the center in the front-back direction and approximately in the center in the left-right direction.

A nut <NUM> (see <FIG>) is located within a space enclosed by the lower face of the support plate <NUM> and the U-shaped metal fitting 71C, and a third bolt <NUM> is inserted from below into the first through-hole 74a of the fixing stay <NUM> and the through hole 71C1 of the metal fitting 71C and screwed with the nut <NUM>. In addition, a fourth bolt <NUM> is inserted from the back into the second through-hole 74b of the fixing stay <NUM> and screwed with the back positioning nut <NUM> (see <FIG>) fixed to the ROPS frame <NUM>. This fixes the support plate <NUM> to the ROPS frame <NUM> via the fixing stay <NUM>.

As described above, the second bolt <NUM> is used thereby to fix the fixing plate <NUM> to the ROPS frame <NUM>, and the third bolt <NUM> and the fourth bolt <NUM> are used thereby to fix the support plate <NUM> via the fixing stay <NUM> to the ROPS frame <NUM>, thereby making it possible to firmly fix the support unit <NUM> to the ROPS frame <NUM>.

Details of the protective pipe <NUM> are described next. The protective pipe <NUM> is composed of a left pipe <NUM> located to the left of the support plate <NUM>'s center in the left-right direction and a right pipe 72R located to the right of the center are connected in the left-right direction in front of the ROPS frame <NUM> and below the support plate <NUM>. A more detailed description is as follows.

With a start point 72L1 (see <FIG>) defined as a position on the left side of the center of the back portion edge 71B of the support plate <NUM> in the left-right direction, the left pipe <NUM> extends to an end portion 71a (see <FIG>) as a left back end portion of the support plate <NUM>. The left pipe <NUM> extends from the end portion 71a of the support plate <NUM> along the left edge <NUM> to the front of the ROPS frame <NUM>. The left pipe <NUM> is disconnected from the left edge <NUM> on the way extending from the end portion 71a of the support plate <NUM> to the front of the ROPS frame <NUM>. The left pipe <NUM> bends downward along the front face <NUM> in front of the ROPS frame <NUM>, extends to a position lower than the transverse frame 60a of the ROPS frame <NUM>, and then is bent rightward and connected with the right pipe 72R.

With the start point 72R1 (see <FIG>) defined as a position on the right side of the center of the back portion edge 71B of the support plate <NUM> in the left-right direction, the right pipe 72R extends to an end portion 71b (see <FIG>) as a right back end portion of the support plate <NUM>. The right pipe 72R extends from the end portion 71b of the support plate <NUM> along the right edge 71R to the front of the ROPS frame <NUM>. The right pipe 72R is disconnected from the right edge 71R on the way extending from the end portion 71b of the support plate <NUM> to the front of the ROPS frame <NUM>. The right pipe 72R bends downward along the front face <NUM> in front of the ROPS frame <NUM>, extends to a position lower than the transverse frame 60a of the ROPS frame <NUM>, and then is bent leftward and connected with the left pipe <NUM>.

The start point 72L1 of the left pipe <NUM> and the start point 72R1 of the right pipe 72R are closed by a closing plate <NUM> (see <FIG> and <FIG>). The closing plate <NUM> is a U-shaped flat plate viewed from the back, and is fixed to the back portion edge 71B of the support plate <NUM> by welding or any other operation. The closing plate <NUM> is located between the start point 72L1 and the start point 72R1. As a result, the start point 72L1 and the start point 72R1 are positioned spaced apart from each other in the left-right direction.

As described above, the support unit <NUM> has the protective pipe <NUM> that is mounted to some of the edges of the support plate <NUM> (back portion edge 71B, left edge <NUM>, and right edge 71R). The protective pipe <NUM> is mounted to the back portion of the support plate <NUM>, specifically to the back portion edge 71B, and extends to the left and right.

Mounting the annular protective pipe <NUM> to some of the edges of the support plate <NUM> can reinforce the support plate <NUM> and thus the support unit <NUM>. With this, even when the work instrument <NUM> (see <FIG>) rises and collides with the support unit <NUM>, the risk of damage to the support unit <NUM> can be securely reduced. Thus, the harness connection portion <NUM> can be reliably protected by the support unit <NUM>.

The protective pipe <NUM> is so configured as to extend forward from each of the left and right end portions 71a, 71b of the back portion edge 71B of the support plate <NUM> along each of the left and right edges <NUM>, 71R of the support plate <NUM>, and to connect in front of the ROPS frame <NUM> and in the left-right direction at a position lower than the support plate <NUM>.

In front of the ROPS frame <NUM> and below the support plate <NUM>, the protective pipe <NUM> is located extending in the left-right direction. With this, even when the driver in the driver seat area <NUM> in front of the ROPS frame <NUM> stands up and the driver's head portion contacts the support unit <NUM>, the possibility of the driver's head portion coming into contact with the protective pipe <NUM> located below the support plate <NUM> is greater than the possibility of the driver's head portion coming into contact with the support plate <NUM>. The protective pipe <NUM> is annular and has a rounded outer surface; therefore, even when the driver's head portion contacts the protective pipe <NUM>, the head portion is less likely to be damaged than when the driver's head portion contacting an edge (e.g., front edge 71F (see <FIG>)) of the support plate <NUM>. That is, the protective pipe <NUM> reduces the damage to the driver's head portion and protects the driver's head portion.

As shown in <FIG> and <FIG>, the tractor <NUM> of the present embodiment is equipped with a first fixing member <NUM>. The first fixing member <NUM> is a member that fixes, to the support unit <NUM> (especially, the support plate <NUM>), a portion of the harness WH connected to the harness connection portion <NUM> of the antenna unit <NUM>. The first fixing member <NUM> is composed of a wiring clamp (wire saddle), for example, but may also be composed of other fixing fixtures such as bands and clips.

The portion of the harness WH is fixed to the support unit <NUM> (especially, the support plate <NUM>) by the first fixing member <NUM>, thus stabilizing the pulling around (distributing) of the harness WH.

As shown in <FIG> and <FIG>, the tractor <NUM> of the present embodiment is further equipped with a second fixing member <NUM>. The second fixing member <NUM> is a member that fixes a portion of the harness WH to the outer surface of the ROPS frame <NUM>. Conceivable examples of the outer surface of the ROPS frame <NUM> include a back face 60a2 (see <FIG>) of the transverse frame 60a of the ROPS frame <NUM>, but the outer surface can also be the upper face of the transverse frame 60a or the outer surface (side face or back face) of the longitudinal frame 60b (see <FIG>). The second fixing member <NUM> is composed of a wiring clamp, for example, but may also be composed of other fixing jigs such as bands, clips, etc. The second fixing member <NUM> may also include a metal fitting that supports the wiring clamp on the outer surface of the ROPS frame <NUM>.

Using the second fixing member <NUM> can pull around the harness WH along the outer surface of the ROPS frame <NUM>. Therefore, compared to the configuration where the harness WH is so pulled around as to pass through the inside of the ROPS frame <NUM>, for example, pulling around of the harness WH is easier. Also, the outer surface of the ROPS frame <NUM> has no need to form the hole for the harness WH to pass through, as in the configuration where the harness WH is so pulled around as to pass through the inside of the ROPS frame <NUM>. This avoids reduction in strength of the ROPS frame <NUM>. Further, merely unfixing the second fixing member <NUM> can easily remove the harness WH from the outer surface of the ROPS frame <NUM>, facilitating maintenance of the harness WH.

<FIG> is a perspective view schematically showing another configuration of the support unit <NUM>. The support unit <NUM> may be fixed to the ROPS frame <NUM> in a manner to support the antenna unit <NUM> in front of the ROPS frame <NUM>. The above support unit <NUM> is so configured as to have a first flat plate portion <NUM>, a second flat plate portion <NUM>, and a coupling portion <NUM>.

The first flat plate portion <NUM> is a flat plate that extends in the front-back and left-right directions and is located in front of the ROPS frame <NUM>. The antenna unit <NUM> is fixed to the first flat plate portion <NUM> from below by bolts or the like. The antenna unit <NUM> is thus supported from below by the first flat plate portion <NUM>. The above first flat plate portion <NUM> is located at the same height as an upper face 60a3 of the transverse frame 60a of the ROPS frame <NUM>, but may be higher than the upper face 60a3.

The second flat plate portion <NUM> is a flat plate that extends in the left-right direction and is located in contact with the lower face 60a1 of the transverse frame 60a of the ROPS frame <NUM>. The second flat plate portion <NUM> is fixed to the lower face 60a1 of the transverse frame 60a by welding or any other operation, but may also be fixed by bolts or the like. In the vertical direction, the coupling portion <NUM> connects the back end of the first flat plate portion <NUM> with the front end of the second flat plate portion <NUM>.

The support unit <NUM> having the first flat plate portion <NUM>, the second flat plate portion <NUM>, and the coupling portion <NUM> may be formed by bending a single metal plate. Further, the support unit <NUM> may be formed in a manner to connect, by welding or otherwise, the first flat plate portion <NUM> with the coupling portion <NUM> and the second flat plate portion <NUM> with the coupling portion <NUM>.

Fixing the antenna unit <NUM> on the first flat plate portion <NUM>, which is located forward of the ROPS frame <NUM>, allows the antenna unit <NUM> itself to be located forward of the ROPS frame <NUM>. Therefore, even when the work instrument <NUM> (see <FIG>) is raised, the harness connection portion of the antenna unit <NUM><NUM> can be prevented from coming into contact with the work instrument <NUM>. As a result, the risk of the harness connection portion <NUM> coming into contact with the work instrument <NUM> and being damaged can be reduced.

In addition, when the antenna unit <NUM> is fixed to the ROPS frame <NUM>, which has the upper portion turnable backward, using the support unit <NUM> shown in <FIG>; before the turning of the ROPS frame <NUM>, the antenna unit <NUM> is located in front of the ROPS frame <NUM>. Therefore, when the upper portion of the ROPS frame <NUM> is turned backward, the ROPS frame <NUM> is likely to come into contact with the work instrument <NUM> before the antenna unit <NUM>, and the antenna unit <NUM> is less likely to come into contact with the work instrument <NUM>. Therefore, even when the antenna unit <NUM> is fixed to the ROPS frame <NUM>, which has the upper portion turnable backward, using the support unit <NUM> shown in <FIG>, the risk of the harness connection portion <NUM> of the antenna unit <NUM> coming into contact with the work instrument <NUM> and being damaged can be reduced.

As shown in <FIG>, the lower face 60a1 of the transverse frame 60A of the ROPS frame <NUM> may have an insertion hole 60P. Then, the harness WH, which is connected to the harness connection portion <NUM> of the antenna unit <NUM>, may be distributed via the insertion hole 60P through the inside of the ROPS frame <NUM>.

Generally, there is a concern that the strength of the ROPS frame <NUM> may be reduced when the ROPS frame <NUM> is configured to be provided with the insertion hole 60P; however, appropriately selecting the material or the like of the ROPS frame <NUM> can secure the minimum necessary strength of the ROPS frame <NUM>. Therefore, on condition that the strength of the ROPS frame <NUM> should be secured, providing the ROPS frame <NUM> with the insertion hole 60P and causing the harness WH to pass through the inside of the ROPS frame <NUM> via the insertion hole 60P can prevent appearance quality deterioration due to the harness WH's exposure to the outside.

In addition, since the insertion hole 60P is formed on the lower face 60a1 of the ROPS frame <NUM> (transverse frame 60a), rainwater falling from above, water during vehicle washing, mud, etc. are unlikely to penetrate into the inside of the ROPS frame <NUM> through the insertion hole 60P. Thus, corrosion of the harness WH due to water and other elements entering the inside of the ROPS frame <NUM> can be reduced.

Provided that the strength of the ROPS frame <NUM> should be secured, the insertion hole 60P may be formed on the back face 60a2 of the ROPS frame <NUM> (e.g., transverse frame 60A).

<FIG> is a perspective view showing still another configuration of the support unit <NUM>. <FIG> is a side view of the support unit <NUM> in <FIG>. The support unit <NUM> may be configured to support the antenna unit <NUM> so that the harness connection portion <NUM> of the antenna unit <NUM> overlaps the ROPS frame <NUM> when viewed from above. Here, "the <NUM> harness connection portions overlaps with the ROPS frame <NUM> viewed from above" means that all of the harness connection portions <NUM> overlap the ROPS frame <NUM> (especially, the transverse frame 60a) when viewed from above. This means that, when viewed from above, the harness connection portion <NUM> is located between the upper portion of the front face <NUM> of the ROPS frame <NUM> and the upper portion of the back face 60a2.

The support unit <NUM> is so configured as to have a support stand <NUM> and a fixing stay <NUM>. The antenna unit <NUM> is fixed to the support stand <NUM> from below by bolts or the like. The antenna unit <NUM> is thus supported from below by the support stand <NUM>. The fixing stay <NUM> is L-shaped in lateral view and is fixed to the support stand <NUM> by welding or any other operation, thereby to support the support stand <NUM> from below. Also, the fixing stay <NUM> is fixed to the upper face 60a3 of the transverse frame 60a of the ROPS frame <NUM> by welding or any other operation.

With the support unit <NUM>, the harness connection portion <NUM> of the antenna unit <NUM> is located in a manner to overlap the ROPS frame <NUM> viewed from above; therefore, even when the work instrument <NUM> (see <FIG>) is raised, the above prevents the harness connection portion <NUM> of the antenna unit <NUM> from coming into contact with the work instrument <NUM>. As a result, the risk of the harness connection portion <NUM> coming into contact with the work instrument <NUM> and being damaged can be reduced.

Even when the support unit <NUM> in <FIG> is applied to the ROPS frame <NUM> whose upper portion is turnable backward, turning the upper portion of ROPS frame <NUM> backward causes the ROPS frame <NUM> to come into contact with the work instrument <NUM> earlier than the harness connection portion <NUM> of the antenna unit <NUM>. Therefore, even when the upper portion of the ROPS frame <NUM> is turned backward, the risk of the harness connection portion <NUM> coming into contact with the work instrument <NUM> and being damaged can be reduced.

<FIG> is a perspective view schematically showing still another configuration of the support unit <NUM>. <FIG> is a side view of the support unit <NUM> in <FIG>. The support unit <NUM> is common to <FIG> in supporting the antenna unit <NUM> so that the harness connection portion <NUM> of the antenna unit <NUM> overlaps the ROPS frame <NUM>, viewed from above. The difference from <FIG> is that the support unit <NUM> supports the antenna unit <NUM> by <NUM>° turning the antenna unit <NUM> to the right from the position in <FIG> by. So as to realize the configuration where the support unit <NUM> supports the antenna unit <NUM> so that the harness connection portion <NUM> overlaps the ROPS frame <NUM>; as shown in <FIG> and <FIG>, the position of fixing the fixing stay <NUM> to the ROPS frame <NUM> by welding or the like is shifted backward from the position shown in <FIG> and <FIG>.

The support unit <NUM> may support the antenna unit <NUM> by <NUM>° turning the antenna unit <NUM> to the left from the position in <FIG>. If the harness connection portion <NUM> overlaps the ROPS frame <NUM> when viewed from above, the turning angle of the antenna unit <NUM> from the position in <FIG> is not limited to <NUM>° described above, but may be any other angle.

Even when the support unit <NUM> is so configured as to support the antenna unit <NUM>, as shown in <FIG>, the same effect as in <FIG> can be acquired. That is, the harness connection portion <NUM> is so located as to overlap the ROPS frame <NUM> when viewed from above; therefore, even when the work instrument <NUM> (see <FIG>) is raised, the harness connection portion <NUM> of the antenna unit <NUM> is prevented from coming into contact with the work instrument <NUM>, making it possible to reduce the risk of damage to the harness connection portion <NUM>. Even when the support unit <NUM> of <FIG> is applied to the ROPS frame <NUM> whose upper portion is turnable backward, the risk of the harness connection portion <NUM> coming into contact with the work instrument <NUM> and being damaged can be reduced when the upper portion of the ROPS frame <NUM> turns backward.

<FIG> is a perspective view schematically showing still another configuration of the support unit <NUM>. The support unit <NUM> may be configured to turn the antenna unit <NUM>. The support unit <NUM> is so configured as to have a support pipe <NUM> and a turn plate <NUM>.

The support pipe <NUM> is so configured as to extend below the transverse frame 60a of the ROPS frame <NUM> in the left-right direction and to bend downward near the longitudinal frame 60b. Both ends of the support pipe <NUM> are fixed to the longitudinal frame 60b by a fixing member <NUM>.

The turn plate <NUM> is so configured as to have a metal plate 222a that is inverted U-shaped viewed from the back, and a support plate 222b connected to the upper portion of the metal plate 222a and extending forward. The metal plate 222a is located behind the transverse frame 60a of the ROPS frame <NUM>. In the left and right directions, the metal plate 222a has two insertion holes 222a1 through which the support pipe <NUM> is inserted. The antenna unit <NUM> is fixed to the support plate 222b by bolts or the like. As a result, the antenna unit <NUM> is supported from below by the support plate 222b.

The support pipe <NUM> is inserted through the insertion hole 222a1 of the metal plate 222a of the turn plate <NUM>, so the turn plate <NUM> is turnable with the support pipe <NUM>, which extends in the left-right direction, as the rotational axis. The support pipe <NUM> itself does not rotate.

<FIG> shows a state seen after turning the turn plate <NUM>. In the state in <FIG>, since the metal plate 222a of the turn plate <NUM> is located behind the transverse frame 60a, the turn plate <NUM> turns so that the antenna unit <NUM> supported by the support plate 222b passes behind the ROPS frame <NUM>. In this configuration, after the turning of the turn plate <NUM>, the antenna unit <NUM> supported by the support plate 222b can be located in front of the ROPS frame <NUM>. Therefore, even when the work instrument <NUM> (see <FIG>) is raised, the harness connection portion <NUM> of the antenna unit <NUM> is prevented from coming into contact with the work instrument <NUM>, thereby reducing the risk of damage to the harness connection portion <NUM>.

The turning of the turn plate <NUM> moves the antenna unit <NUM> to a lower position (the overall height of the tractor <NUM> is lowered). At the time of storing the tractor <NUM> in a barn, this allows the tractor <NUM> to be stored in a barn without the antenna unit <NUM> contacting the upper portion of the barn entrance. Further, the turn plate <NUM> turns such that the antenna unit <NUM> passes behind the ROPS frame <NUM>, thus preventing as much as possible the antenna unit <NUM> from interfering (having a contact) with the driver in the driver seat area <NUM> in front of the ROPS frame <NUM>.

The metal plate 222a of the turn plate <NUM> may be located in front of the transverse frame 60a. Then, the turn plate <NUM> is so configured as to rotate such that the antenna unit <NUM> passes in front of the ROPS frame <NUM>. Even with this configuration; after the turning of the turn plate <NUM>, the antenna unit <NUM>, which is supported by the support plate 222b, can be located in front of the ROPS frame <NUM>. Therefore, even when the work instrument <NUM> is raised, the harness connection portion <NUM> of the antenna unit <NUM> is prevented from contacting the work instrument <NUM>, making it possible to reduce the risk of damage to the harness connection portion <NUM>.

<FIG> is a perspective view schematically showing still another configuration of the support unit <NUM>. As shown in <FIG>, the support unit <NUM> may be configured to rotate the antenna unit <NUM> in combination with the support pipe <NUM> as a whole. The support unit <NUM> is so configured as to have the support pipe <NUM>, a turn plate <NUM>, and a hinge portion <NUM>.

The support pipe <NUM> is so configured as to extend in front of the transverse frame 60a of the ROPS frame <NUM> in the left-right direction, and to be bent downward near the longitudinal frame 60b. Both ends of the support pipe <NUM> are fixed to the longitudinal frame 60b via the hinge portion <NUM>.

The turn plate <NUM> is fixed to the support pipe <NUM> by welding or any other operation. The antenna unit <NUM> is fixed to the turn plate <NUM> by bolts or the like. The antenna unit <NUM> is thus supported from below by the turn plate <NUM>.

The hinge portion <NUM> is a turn mechanism by which the support pipe <NUM> is rotatably connected to the ROPS frame <NUM> (particularly longitudinal frame 60b). The hinge portion <NUM> allows the support pipe <NUM> to rotate relative to the ROPS frame <NUM>, with the left and right directions as the rotational axis.

<FIG> shows a state seen after the support pipe <NUM> is rotated together with the turn plate <NUM>. In the state shown in <FIG>; since the support pipe <NUM> is located in front of the transverse frame 60a of the ROPS frame <NUM>, the turn plate <NUM> is rotated together with the support pipe <NUM> so that the antenna unit <NUM> supported by the turn plate <NUM> passes in front of the ROPS frame <NUM>. In this configuration, after the turning of the turn plate <NUM>, the harness connection portion <NUM> (see <FIG>) of the antenna unit <NUM> supported by the turn plate <NUM> can be located in front of the ROPS frame <NUM>. Thus, even when the work instrument <NUM> (see <FIG>) is raised, the harness connection portion <NUM> is prevented from coming into contact with the work instrument <NUM>, making it possible to reduce the risk of damage to the harness connection portion <NUM>.

The antenna unit <NUM> moves to a lower position due to the turning of the turn plate <NUM>; therefore, at the time of storing the tractor <NUM> in the barn, the tractor <NUM> can be stored in the barn without the antenna unit <NUM> coming in contact with the upper portion of the barn entrance. Further, the hinge portion <NUM> allows the support pipe <NUM> to turn together with the turn plate <NUM> and to move to the lower position, so that, after the turning, the backward view from the driver in the driver seat area <NUM> can be widely secured (the backward view is not obstructed by the support pipe <NUM>). This makes it easier for the driver to visually check the back.

The support pipe <NUM> may be located backward of the transverse frame 60a. Then, it may be so configured that the turn plate <NUM> turns together with the support pipe <NUM> such that the antenna unit <NUM> passes behind the ROPS frame <NUM>. Even with this configuration, after the turning of the turn plate <NUM>, the harness connection portion <NUM> of the antenna unit <NUM> supported by the turn plate <NUM> can be located in front of the ROPS frame <NUM>. Therefore, even when the work instrument <NUM> is raised, the harness connection portion <NUM> is prevented from contacting the work instrument <NUM>, making it possible to reduce the risk of damage to the harness connection portion <NUM>.

The embodiment of the present invention has been described above, but the scope of the present invention is not limited thereto and can be carried out within an extended or modified range without departing from the the present invention as defined by the appended claims.

Claim 1:
A work vehicle (<NUM>) comprising:
a vehicle body (<NUM>) to which a work instrument is connected at a back; and
a roll-over protection structure (ROPS) frame (<NUM>) erected at a back portion of a driver seat area (<NUM>) in the vehicle body (<NUM>),
wherein the work vehicle (<NUM>) further comprises:
a positioning unit (<NUM>) that detects a position of the vehicle body (<NUM>) based on a signal sent from a positioning satellite, and
a support unit (<NUM>) that is fixed to an upper portion of the ROPS frame (<NUM>) and supports the positioning unit (<NUM>) from below, and
the positioning unit (<NUM>) has a harness connection portion (<NUM>) that is connected to a harness (WH) for sending information to outside,
the harness connection portion (<NUM>) is located at a back portion of the positioning unit (<NUM>), and
the support unit (<NUM>) is located protruding backwardly from the harness connection portion (<NUM>) of the positioning unit (<NUM>).