JPS5849431B2 - cab lifting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for lifting the cab of a cab-over type vehicle, which is necessary when inspecting or repairing the engine room of the vehicle.

In a cab-over type automobile, the driver's cab is provided above the engine room, so the driver's cab must be lifted up when inspecting or repairing the engine room.

Therefore, one of the conventional cab lifting devices is to use a hydraulic cylinder, but this method number ζ
In such cases, when the driver's cab is set in a normal state and the vehicle is running, the hydraulic cylinder is directly subjected to vertical vibrations in the driver's cab, which deteriorates the ride comfort of the vehicle. It will end up being put away.

To solve this problem, conventional techniques have been used to prevent the hydraulic cylinder from experiencing so-called lost motion.
) is employed to escape the vibrations, but this structure is complicated and expensive.

On the other hand, there is a method of mechanically disconnecting the driver's cab from the hydraulic cylinder to achieve this lost motion, but this conventional method involves fitting a pin orthogonally to the piston rod of the hydraulic cylinder. Since the pin is configured to selectively lock into or disengage from an arcuate groove provided in the driver's cab, the piston rod is rotated around the rod axis so that the pin can be inserted into the groove in its proper position. A rotation stopper must be provided to prevent it from rotating.

Since there is surface contact and the contact between the groove and the pin is a line contact, countermeasures against stress on the contact surface become a problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a driver's cab lifting device for an automobile that eliminates the above-mentioned problems.

To explain the present invention based on an embodiment, FIG. 1 shows a side view of a driver's cab lifting device as an embodiment of the present invention when it is attached to an automobile, and FIG. 1 shows a side sectional view of the support 3 in FIG. 1, and FIG. 3 shows a cross section in FIG. 1, and FIG. 3 also corresponds to the Rollo cross section in FIG. 2. There is.

However, unlike FIG. 2, FIG. 3 shows a state in which the piston rod 5 is fully retracted toward the hydraulic actuator 4.

As shown in FIG. 1, the cab lifting device according to the present invention includes a hydraulic actuator 4, a pinuton rod (hereinafter referred to as "rond") 5 in the hydraulic actuator 4, and a support 3.
and a switching valve that operates the hydraulic actuator 4; however, in FIG. 1, the switching valve is shown for convenience of explanation.
It is omitted.

In the embodiment of FIG. 1, the axial end 4a of the hydraulic actuator is pivotally connected to the chassis 2 of the vehicle, and the support 3
is fixed on the driver's cab 1, and in such a posture,
As the rod 5 extends upward, the driver's cab 1 can be tilted around a fulcrum pivoted at the front of the chassis 2, as shown in FIG.

As shown in FIGS. 2 and 3, the structure of the support 3 is such that the trunnions 3a on both sides pivotally support the trunnion shaft 3b via their respective bearings 3C, and at the axial center of the trunnion shaft 3b, A hole 3d is bored perpendicular to the center line of the trunnion shaft 3b, and the hole 3d is configured to slidably guide the movement of the rod 5 in the axial direction. A taper is formed, and the trunnion shaft 3
A female spherical receiving surface 3e is formed on the lower side of the trunnion shaft 3b, centered at the intersection 3h of the axial centerline of b and the axial centerline of the perforation 3d.

In the trunnion shaft 3b, the tip of the rod 5 is fitted into the borehole 3d to allow sliding movement in the axial direction, the collar 5a is fixed to the rod 5 by a pin 5d, and the pin 5e is fixed to the rod 5. The front surface 5c of the collar 5a has a male taper with the same taper as the side edge 3g, and the rear surface of the collar 5a has the same taper as the side edge 3g. 5b forms a male-shaped spherical surface having a radius of curvature that is the same as or slightly smaller than the radius of curvature of the spherical shape on the receiving surface 3e, and the rear surface 5b
The spherical surface is formed around the outer circumferential direction of the rod 5, and as shown in FIG. The configuration is such that they have a consistent spherical shape.

To explain its function in the above configuration, it is in the state shown in Figure 3, that is, in the state in which the rod 5 is retracted the shortest, and at this time the driver's cab has returned to the position where it is ready to drive the car. In this state, when the car is driven, the driver's cab 1 generally vibrates relative to the chassis 2, but in this case, the support 3 fixed to the driver's cab 1 can freely move up and down with respect to the rod 5. The riding comfort resulting from the vibrations can be made comfortable by means of an independent device with a spring structure (not shown).

When inspecting or repairing the engine, etc. located at the bottom of the driver's cab 1 from the above-mentioned normal driving position, operate the hydraulic actuator 4 and extend the rod 5.
The front surface 5C of the brim 5a eventually comes into contact with the side edge 3g, and as the rod 5 further extends, the rod 5 becomes
The driver's cab 1 is lifted up as shown in FIG. 1 via the collar 5a, trunnion shaft 3b, and support 3.

In this way, in the process of Tanodo 5 lifting the driver's cab 1, the center of gravity of the driver's cab 1 rotates counterclockwise around the pivot point on which the driver's cab 1 is tilted. From the initial start of operation until the center of gravity is on the vertical line of the pivot center, the weight of the driver's cab 1 is supported by the rods 5 and pushed up.

On the other hand, when the center of gravity passes over the vertical line passing through the pivot center and moves to the left of the vertical line (Fig. 1), the cab 1 moves further counterclockwise due to its own weight. After entering this state, the rod 5 must be able to support the movement of the driver's cab 1 in a tensile manner.

Below, from just before the center of gravity of the driver's cab 1 passes through the vertical line,
The effect of this passing process will be explained.

When the driver's cab 1 is tilted counterclockwise around the pivot center, the base 5 is aligned with the support 3 at the intersection 3.
It rotates relatively clockwise around h (Fig. 2).

In this case, the state shown in FIG. 2 shows the state just before the center of gravity of the driver's cab 1 passes through the vertical line passing through the pivot center, as described above, and as this state progresses, the rod 5 As it extends further, the collar 5a further rotates clockwise around the intersection 3h.

In this rotation of the brim 5a, the back surface 5b of the brim 5a has a spherical shape with the same or almost the same radius of curvature as the receiving surface 3e.
As the rod 5 extends, the rod b slides into the receiving surface 3e, and as the rod 5 further extends from this state, the weight of the driver's cab acts in the direction of pulling the rod 5, as described above. Therefore, when this state is entered, the receiving surface 3e fixed to the driver's cab 1 is pressed against the back surface 5b by the gravity, and as a result, the pressing force is applied via the collar 5a and the rod 5. , the driver's cab 1 is tilted to a predetermined position while being supported by the hydraulic actuator 4.

In the above action, the end portion 4a of the hydraulic actuator 4
is pivotally attached to the chassis 2, but from the above explanation, it is also possible to conversely have the end portion 4a pivoted to the driver's cab 1 side and the support 3 to be fixedly attached to the chassis 2 side. It will be easily understood.

As is clear from the above explanation, in the cab lifting device of the present invention, the rod 5 can freely rotate around the axial center of the rod 5 in the structure of the normal hydraulic actuator 4. However, since the collar 5a forms a back surface 5b that is symmetrical in the outer circumferential direction of the rod 5, even if the rod 5 rotates around the axis, the receiving surface 3 of the back surface 5b
The shape for e is always the same shape.

As a result, even if the rod 5 does not have a complicated device such as a rotation stopper around the center of the axis, the back surface 5b can be
This allows it to slide onto the receiving surface 3e when always in a required position.

Further, in the driver's cab lifting device of the present invention, since the back surface 5b and the receiving surface 3e are mutually spherical, the mutual contact during the sliding is a surface contact, and as a result, the counter pressure during the contact is extremely reduced. It has the advantage of being able to be made smaller, making it easier to select materials for the collar 5a and/or the receiving surface 3e, and reducing the surface pressure of the contact.
It is also possible to appropriately reduce the frictional force in the contact by using an appropriate bearing material or the like.

Further, in the driver's cab lifting device according to the present invention, the collar 5
When the front surface 5c in a is made into a convex taper, even if a foreign object gets on the front surface 5c, the foreign object will inevitably roll or slide down due to the tapered shape. In the state where the front surface 5c is in contact as shown in FIG. 2, there is no possibility that the foreign object will be caught between the two and the rear surface 5b will not be able to enter the receiving surface 3e. It is something.

Moreover, in the driver's cab lifting device according to the present invention, when the front surface 5c is formed in a tapered shape as described above,
Furthermore, when the side end 3g is also tapered in the same way as the tapered shape, it becomes possible to sufficiently reduce the surface pressure of the rod 5 supporting the driver's cab 1 at the side end 3g, so that the rib 5
This makes it possible to easily select materials for the shaft a and the trunnion shaft 3b, and reduce the manufacturing cost.

[Brief explanation of the drawing]

FIG. 1 shows a side view of the driver's cab lifting device according to the present invention installed in an automobile, FIG. 2 shows a side sectional view of the support 3 in FIG. 1, and FIG. , which shows the ii break in Figure 1 or the Roro break in Figure 2, but in this case, the rod 5 in Figure 3 is
corresponds to the position of the rod 5 when the rod 5 is retracted the most from the state shown in FIG. The symbols used in the examples are as follows. 1: Cab, 2: Chassis, 3: Support, 3a: Trunnion, 3b: Trunnion shaft, 3c: Bearing, 3d: Perforation,
3e: receiving surface, 3f: space, 3g: side edge, 3h: intersection, 4: hydraulic actuator, 4a: end, 5: piston rod, 5a: collar, 5b: back, 5c: front, 5d
and 5e: pin.

Claims (1)

[Claims] 1. Either the cab 1 or the chassis 2 includes:
The end 4a of the hydraulic actuator 4 is pivotally mounted, a support 3 is fixed to either the chassis or the driver's cab, and the piston rod 5 of the hydraulic actuator has a side end that is a part of the support. A rib 5a that selectively abuts against the piston rod 3g is fixed, and the rear surface 5b of the rib facing toward the hydraulic actuator forms a spherical shape symmetrical around the outer diameter of the piston rod, and Between the tool and the piston rod, there is a shaft support structure in which the piston rod rotates and oscillates in a pendulum shape with respect to the support tool about a fixed point 3h in the support tool; , a receiving surface 3e is formed on both sides of the space 3f in which the piston rond rotates and swings, the receiving surface has a spherical shape centered on the fixed point and pivotally supporting the spherical surface of the back surface, When the piston rond rotates and oscillates in the operating state in which the piston rond contacts the side edge and lifts the cab,
A driver's cab lifting device characterized in that the back surface is guided on the receiving surface. 2. The driver's cab lifting device according to claim 1, wherein the front surface 5c of the flange 5a has a tapered shape convex toward the intersection 3h. 3. The driver's cab lifting device according to claim 2, wherein the shape of the side end portion 3g is a female taper having the same taper as the front surface of the flange 5a.