JPH0116717B2 - - Google Patents

Description

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

In cab-over type automobiles, 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.
In the case of this method, when the driver's cab is set to a normal state and the vehicle is in a running state, the hydraulic cylinder directly receives vertical vibrations in the driver's cab, which deteriorates the ride comfort of the vehicle. You will end up letting it happen.

To solve this problem, so-called lost motion (lost motion) has traditionally been applied to the hydraulic cylinder.
However, this configuration is complicated and expensive.

On the other hand, there is a method of mechanically disconnecting the driver's cab from the hydraulic cylinder to perform the 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 rotates around the rod axis to ensure that the pin enters the groove in its proper position. There is the trouble of having to provide a detent to prevent this from happening, and since 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 cross-sectional view of the support 3 in FIG. 1, and FIG. 3 shows a cross-sectional view taken along a line in FIG. 2. However, unlike FIG. 1, FIGS. 2 and 3 show a state in which the piston 5 is retracted the most toward the hydraulic actuator 4.

As shown in FIG. 1, the cab lifting device according to the present invention is composed of a hydraulic actuator 4, a piston 5 in the hydraulic actuator 4, a support 3, and a switching valve for operating the hydraulic actuator 4. In FIG. 1, illustration of the switching valve is omitted for convenience of explanation.

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

As shown in FIGS. 2 and 3, the support 3 has a structure in which holes 3k and 3m are bored in the direction of a vertical line erected on the side of the driver's cab 1. , the pin 3a is fitted, the member 3b is fitted or attached to the pin 3a, the outer shape of the member 3b is spherical, and the spherical part is fitted to one end of the rod 3j. Bearing material 3
c is pivoted to allow rocking rotation.

The piston 5 in the hydraulic actuator 4 has an axial center portion that is hollow or tubular, and a collar 5a is screwed onto the tubular portion at the tip of the piston 5.
b, a convex spherical surface is formed in a symmetrical shape in the outer circumferential direction of the piston 5, and the center of the spherical shape is
When the front surface 5c of the collar 5a is in contact with the side edge 3g provided on the rod 3j, the intersection point 3h of the axis of the pin 3a and the axis 3i of the rod 3j (which is also the spherical center of the outer spherical surface of the member 3b) This is consistent with the following.

Rails 3e, 3e are formed on the parts of the support 3 on both sides of the space 3f in which the rod 3j rotates around the axis of the pin 3a.
The surface forms a concave spherical surface centered at the intersection point 3h.

To explain its operation in the above configuration, in the state shown in Fig. 3, that is, the state in which the piston 5 is retracted the shortest, the driver's cab has returned to the position where the car is ready to be driven. In this state, when the car is driven, the driver's cab 1 generally vibrates in the vertical direction with respect to the chassis 2, but in this case, the support 3 fixed to the driver's cab 1 vibrates with respect to the piston 5. This means that it can freely vibrate vertically. This is because the rod 3j is configured to be able to freely vibrate in the vertical direction in the portion of the perforation 5d, and as a result, the ride quality caused by the vibration can be made comfortable by an independent shock absorbing device.

When inspecting or repairing the engine, etc. located at the bottom of the driver's cab 1 from the above-mentioned normal driving position, when the hydraulic actuator 4 is activated and the piston 5 is extended, the front surface of the collar 5a
c eventually comes into contact with the side edge 3g, and as the piston 5 further extends, the piston 5 touches the flange 5.
a, lift the driver's cab 1 via the rod 3j, pin 3a and support 3 as shown in FIG.

In this way, in the process of the piston 5 lifting the cab 1, the center of gravity of the cab 1 is
The driver's cab 1 rotates counterclockwise in FIG. The piston 5 supports this weight and pushes it 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 against the vertical line due to its own weight. The piston 5 will try to rotate clockwise, and once it enters this state, the piston 5 must be able to support the movement of the driver's cab 1 in a tensile manner.

Hereinafter, before the center of gravity of the driver's cab 1 passes through the vertical line, the operation of the process of passing through the vertical line will be explained.

As described above, as the piston 5 is pushed up, the front surface 5c of the collar 5a comes into contact with the side surface end 3g of the rod 3j, and when the piston 5 is pushed up further after this contact, the piston 5 pushes the driver's cab 1. Since the driver's cab 1 is pushed up as shown in FIG. 1 and tilted as shown in FIG. It rotates counterclockwise.

As a result, due to this rotation, the back surface 5b of the collar 5a slides into the rails 3e, 3e,
When the piston 5 further extends from this state, the weight of the driver's cab 1 acts in the direction of pulling the piston 5 as described above. 3e, 3e
is pressed against the back surface 5b by the gravity, and as a result, the pressing force is supported by the hydraulic actuator 4 via the collar 5a and the piston 5, and the driver's cab 1 is tilted to a predetermined position. I will do it.

In addition, in the above action, while the car is running,
Alternatively, even if the driver's cab 1 shakes laterally when lifting the driver's cab as shown in Fig. 1, since the member 3b supports the rod 3j on a spherical axis, the shaking will be caused by the spherical axis. This prevents the support 3, the piston 5, or the hydraulic actuator 4 from being damaged or having their durability deteriorated due to the shaking.

In the above action, the end 4a of the hydraulic actuator 4 is pivotally connected to the chassis 2, but conversely, the end 4a is pivotally connected to the driver's cab 1 side, and the support 3
It will be easily understood from the above description that it may be fixedly attached to the chassis 2 side.

As is clear from the above description, in the cab lifting device of the present invention, in the configuration of the normal hydraulic actuator 4, the piston 5 can freely rotate around the axial center of the piston. , the collar 5a forms a back surface 5b that is symmetrical in the outer circumferential direction of the piston 5, so even if the piston 5 rotates around the axis, the shape of the back surface 5b relative to the rails 3e, 3e is always the same shape. It's summery. As a result, the back surface 5b can always slide onto the rails 3e, 3e when the piston 5 is in the required position, even if the piston 5 is not provided with a complicated device such as a rotation stopper around the axis center. possible, and the piston 5 and rod 3j
Lost motion is made possible by separating the two.

Further, the driver's cab lifting device in the present invention has a rear surface 5.
b and the rails 3e, 3e mutually have spherical shapes, the mutual contact during the sliding motion is a surface contact, and as a result, it is possible to extremely reduce the surface pressure at the contact, and the brim 5a and/or the rails 3e, 3e, and in order to reduce the surface pressure of the contact, an appropriate bearing material or the like is used to moderate the frictional force in the contact. It is also possible to lower the amount.

In addition, in the driver's cab lifting device according to the present invention, when the member 3b supports the rod 3j on a spherical surface, the support 3, the rod 3j, the piston 5
Alternatively, the hydraulic actuator 4 is prevented from being subjected to unreasonable stress caused by the horizontal shaking of the driver's cab 1, etc., thereby contributing to improving the durability of the support and the like.

[Brief explanation of drawings]

FIG. 1 shows a side view of a driver's cab lifting device as an embodiment of the present invention installed in a car, and FIG. 2 shows a cross-sectional view of the support 3 in FIG. 1. , FIG. 3 shows a Rollo sectional view in FIG. 2. The symbols used in the examples are as follows. 1: Cab, 2: Chassis, 3: Support, 3
a: pin, 3b: member, 3c: bearing material, 3d: perforation, 3e: rail, 3f: space, 3g: side edge, 3h: intersection, 3i: axis, 3j: rod, 3
k and 3m: perforation. 4: Hydraulic actuator,
4a: End. 5: Piston, 5a: Brim, 5b:
Back, 5c: Front, 5d: Perforation.

Claims (1)

[Scope of Claims] 1. An end portion 4a of a hydraulic actuator 4 is pivotally connected to either the cab 1 or the chassis 2, and a support 3 is fixed to the other of the chassis or the cab, In the support device,
A rod 3j that is capable of rotating and swinging is pivotally connected at least about a vertical line erected on the side of the driver's cab, the rod is provided with a side end 3g, and the piston 5 of the hydraulic actuator is provided with a side end 3g. A collar 5a that selectively abuts the end is fixed, a hole 5d is bored in the collar in the same direction as the axial direction of the piston, and the rod is provided with a sliding movement in the axial direction in the hole. The rear surface 5b of the rib in the axial direction is provided with a convex spherical surface that is symmetrical in the outer circumferential direction of the piston, and the center of the spherical surface is such that the rib is in contact with the end of the side surface. In the state of contact, the space 3f coincides with the intersection 3h of the vertical line and the axial center 3i of the rod, and the piston swings and rotates around the vertical line with the collar abutting the side edge. Rails 3e, 3e are fixedly installed on both sides, and the surfaces of the rails form a concave spherical surface centered at the intersection 3h, and the ribs abut against the side edges, so that the piston moves during the operation. A driver's cab lifting device characterized in that when the platform is lifted, the back surface slides onto the rail. 2. The rod 3j is pivotally attached to the support 3 by fixing the pin 3a in the vertical direction on the support 3,
The pin is provided with a member 3b having a spherical outer shape,
2. A driver's cab lifting device according to claim 1, wherein one end of said rod is pivotally connected to said spherical portion of said member. 3. The configuration in which the collar 5a is fixed to the piston 5 is achieved by cutting a screw into a tubular inner hole formed at the tip of the piston and bored in the axial direction of the piston,
The driver's cab lifting device according to claim 1 or 2, wherein the collar is screwed onto the threaded portion.