CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2019-171941 filed Sep. 20, 2019, the disclosure of which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a work vehicle including left and right axle cases of a rigid axle type, the left and right axle cases coaxially supporting left and right axles for driving left and right wheels, respectively.

BACKGROUND ART

An example work vehicle configured as above is disclosed in JP 2009-67082 A. JP 2009-67082 A describes a rigid axle suspension for suspending left and right wheels, the rigid axle suspension including (i) a pair of left and right arms for positioning the left and right wheels in the front-rear direction, (ii) a pair of left and right coil springs and a pair of left and right dampers for absorbing shock from a road surface, and (iii) a lateral rod for positioning the left and right wheels in the left-right direction.

The work vehicle disclosed in JP 2009-67082 A further includes (i) a body frame having a rear end portion supporting a pair of left and right arms at an upper position and a pair of left and right arms at a lower position in such a manner that each pair of left and right arms are swingable on the core of a lateral shaft, (ii) an auxiliary frame connected with the pair of left and right arms, the auxiliary frame supporting left and right rear axle cases, and (iii) coil springs and dampers connected with each other in such a manner as to reduce up-down movement of the auxiliary frame. The lateral rod is, in particular, oriented laterally by (i) connecting a first end thereof with the body frame (“base frame” in the patent literature) and (ii) connecting a second end thereof with the auxiliary frame.

SUMMARY OF INVENTION

Technical Problem

The work vehicle disclosed in JP 2009-67082 A is configured such that the lateral rod has a first end connected with a bracket provided for the body frame and a second end connected with a bracket provided for the auxiliary frame.

A lateral rod receives a strong lateral force for positioning left and right wheels in the lateral direction relative to the body frame. The brackets disclosed in JP 2009-67082 A each need to have a great strength.

While an off-road multipurpose work vehicle is running, its wheels often become moved up and down greatly. Even for a work vehicle including coils and dampers as disclosed in JP 2009-67082 A, the wheels can reach their mechanical limits if lifted suddenly and greatly.

A work vehicle including wheels that can reach their mechanical limits if lifted suddenly and greatly as described above will unfortunately let the driver feel the shock, and thus has room for improvement. Further, the use of brackets, for example, for supporting a lateral rod involves an increase in the number of parts used and structural complexity.

This has led to a demand for a work vehicle that allows a lateral rod to be supported without an increase in the number of parts used and that regulates lateral displacement of left and right wheels.

Solution to Problem

A work vehicle according to the present invention comprises: a left wheel provided for a vehicle body; a right wheel provided for the vehicle body; a body frame provided for the vehicle body; a left axle connected with the left wheel; a right axle connected with the right wheel; a left axle case and a right axle case, the left and right axle cases being of a rigid axle type and supporting the left and right axles so that the left and right axles are coaxial with respect to each other; a left suspension mechanism via which the body frame supports the left axle case; a right suspension mechanism via which the body frame supports the right axle case; a first projection projecting downward from a left or right portion of the body frame; a second projection projecting upward from that position on either (i) the left and right axle cases or (ii) a frame body integrated with the left and right axle cases which is opposite to the first projection in a left-right direction; and a lateral rod having a first end connected with the first projection and a second end connected with the second projection.

With the above configuration, the lateral rod has (i) a first end connected with a first projection projecting downward from the body frame and (ii) a second end connected with a second projection projecting upward from that position on either the axle cases or the frame body which is opposite to the first projection in the left-right direction. The above configuration thus allows a lateral rod to be provided without use of brackets. The first projection is present on the body frame, whereas the second projection is present on either an axle case or the frame body. Placing a lateral rod between the first and second projections allows the body frame and left and right wheels to be positioned in the left-right direction.

In particular, if the work vehicle has received an external force that acts in such a manner as to laterally displace the axle cases, the second projection on an axle case allows the force to be transmitted from the lateral rod directly to the axle cases, thereby achieving a strong regulation.

With the above configuration, the work vehicle allows a lateral rod to be supported without an increase in the number of parts used and regulates lateral displacement of left and right wheels.

The work vehicle may further comprise a first opposing portion at that portion of either the left and right axle cases or the frame body which is located below the first projection; a first buffer member on either a lower surface of the first projection or the first opposing portion; a second opposing portion at that portion of the body frame which is located above the second projection; and a second buffer member on either an upper surface of the second projection or the second opposing portion.

With the above configuration, if the wheels have become lifted greatly, the first buffer member (which is present between the first projection and the first opposing portion) and the second buffer member (which is present between the second projection and the second opposing portion) prevent the wheels from disadvantageously reaching their mechanical limits and absorb the shock at the same time. Further, the first projection and the second projection, each of which has a great strength, rigidly support the lateral rod and thereby strongly regulate lateral displacement of left and right wheels.

With the above configuration, the first projection and the second projection overlap with the axle cases in a plan view. Thus, if the wheels have become lifted greatly, the force caused by the axle cases being lifted can be received by the buffer members located at such positions that the force is linearly applied to the buffer members, thereby allowing the force to be reliably received with a great strength.

The work vehicle may further be configured such that the first opposing portion is an upper surface of the frame body; the first buffer member is present on the lower surface of the first projection; the second opposing portion is a lower surface of a bar-shaped member projecting downward from the body frame; and the second buffer member is present on the second opposing portion.

With the above configuration, if the wheels have become lifted greatly, the first buffer member on the lower surface of the first projection comes into contact with the upper surface of the frame body, while the second buffer member on the lower surface of the bar-shaped member comes into contact with the upper surface of the second projection.

The above configuration allows the first buffer member and the second buffer member to be separated from the ground in the upward direction. The above configuration thus prevents muddy water and dust from adhering to and thereby degrading the first buffer member and the second buffer member in the case where the first buffer member and the second buffer member are each made of a rubber, for example.

The work vehicle may further be configured such that the first buffer member and the second buffer member are present at respective heights that are asymmetrical to each other in the left-right direction with respect to a center of the vehicle body as viewed in a front-rear direction.

For instance, with the lower end of the first projection being lower in position than the upper end of the second projection, while the first buffer member and the second buffer member are present at respective heights that are asymmetrical to each other with respect to the center of the vehicle body, the lateral rod can be oriented substantially horizontally as viewed in the front-rear direction. Orienting the lateral rod horizontally as such allows the lateral rod to receive force in a compressing direction and a tensile direction along its longitudinal direction. If an external force is applied that acts in such a manner as to laterally displace the left and right rear wheels, the lateral rod regulates the displacement strongly.

The work vehicle may further be configured such that the left and right wheels are rear wheels provided at a rear portion of the vehicle body.

With the above configuration, the lateral rod allows the body frame and the left and right rear wheels to be positioned in the left-right direction even for a work vehicle in which the respective axles of the rear wheels are supported respectively by the left and right axle cases of a rigid axle type.

